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World History/Revolution, Change, and philosophy. 10.2 Students compare and contrast the Glorious Revolution of England, the American Revolution, and the French Revolution and their enduring effects worldwide on the political expectations for self-government and individual liberty.. 1. Compare the major ideas of philosophers and their effects on the democratic revolutions in England, the United States, France, and Latin America (e.g., John Locke, Charles-Louis Montesquieu, Jean-Jacques Rousseau, Simón Bolívar, Thomas Jefferson, James Madison). 2. List the principles of the Magna Carta, the English Bill of Rights (1689), the American Declaration of Independence (1776), the French Declaration of the Rights of Man and the Citizen (1789), and the U.S. Bill of Rights (1791). 3. Understand the unique character of the American Revolution, its spread to other parts of the world, and its continuing significance to other nations. 4. Explain how the ideology of the French Revolution led France to develop from constitutional monarchy to democratic despotism to the Napoleonic empire. 5. Discuss how nationalism spread across Europe with Napoleon but was repressed for a generation under the Congress of Vienna and Concert of Europe until the Revolutions of 1848.

World History/The Industrial Revolution. Objectives. 10.3 Students analyze the effects of the Industrial Revolution in England, France, Germany, Japan, and the United States. 1. Analyze why England was the first country to industrialize. 2. Examine how scientific and technological changes and new forms of energy brought about massive social, economic, and cultural change (e.g., the inventions and discoveries of James Watt, Eli Whitney, Henry Bessemer, Louis Pasteur, Thomas Edison). 3. Describe the growth of population, rural to urban migration, and growth of cities associated with the Industrial Revolution. 4. Trace the evolution of work and labor, including the demise of the slave trade and the effects of immigration, mining and manufacturing, division of labor, and the union movement. 5. Understand the connections among natural resources, entrepreneurship, labor, and capital in an industrial economy. 6. Analyze the emergence of capitalism as a dominant economic pattern and the responses to it, including Utopianism, Social Democracy, Socialism, and Communism. 7. Describe the emergence of Romanticism in art and literature (e.g., the poetry of William Blake and William Wordsworth), social criticism (e.g., the novels of Charles Dickens), and the move away from Classicism in Europe. The Industrial Revolution. In 1750, most people in Europe lived on small farms and produced most of their needs by hand. By the middle of the 19th century, many people lived in cities and most of their needs were produced by complex machines using steam power. The Industrial Revolution began in Great Britain and spread to Belgium, France, Germany, the United States and Japan. It was a fundamental change in the way goods were produced, and altered the way people lived. The Industrial Revolution is a major turning point in world history. Why Great Britain? Great Britain became the focus of the Industrial Revolution for a variety of reasons: the start of the Agrarian Revolution, an abundance of natural resources, available capital, and the political will to support innovation. The Agrarian Revolution was a change in farming methods that allowed for a greater production of food. This revolution was fueled by the use of new farming technology such as the seed drill and improved fertilizers. The results of this revolution in farming was a population explosion due to the higher availability of food. Also, the Enclosure Movement, which was the consolidation of many small farms into one large farm, left many people jobless and homeless. These people provided the workforce of the Industrial Revolution. Great Britain's geography provides them with an abundance of the natural resources needed for industrialization, such as iron ore and coal. Britain also had access to many navigable rivers and natural harbors which provided for the easy movement of goods both within the country, and overseas. The British overseas empire provided them with a strong economy, this produced the capital (money) needed to build railroads, factories, and mines. Politically, British entrepreneurs enjoyed a high degree of freedom from state control, compared to their counterparts in France, Russia and other parts of Europe. A relatively fair court system existed to enforce contracts and settle disputes among capital owners. These factors may have allowed new technologies and energy resources to take root and flourish. Britain experienced a revolution in energy use as they switched from animal power, to water power, to steam power in a few short years. The steam engine was the power source of the Industrial Revolution. Effects. Philosophy. The philosophy of Communism appeared as a reaction to the condition of the Working Class in industrial society. Karl Marx wrote in The Communist Manifesto (1848) that all of human history is based on the conflict between the bourgeoisie (those who control the means of production) and the proletariat (working class). He predicted that the proletariat would rise up in a violent revolution to overthrow the bourgeoisie and create a society with an equal distribution of goods and services. This socialist theory would form the basis for the Bolshevik, Chinese, and Cuban Revolutions in the 20th Century. The United States had a very strong reaction to these events. Imperialism. Due to the need for raw materials and new markets, the industrialized nations took control of Africa, India, South East Asia, and others. Imperialism had a negative effect on most of these cultures, and did not completely end until after World War II. Most of the benefits of imperialism accrued to the European nations. The Industrial Revolution was a major turning point in world history as it resulted in a complete change in society on all levels. Effects of the Industrial Revolutions were long reaching, and influenced many other cultures both positively and negatively.

World History/Causes and course of the First World War. Before the Great War. Factors Leading to War. Constant colonial tensions among the great powers had given rise to the possibility of a great war between the major European powers. For almost a hundred years, since the fall of Napoleon, a remarkable series of events kept the relative peace. But as 1914 approached, tensions began to rise in a number of countries, and key issues began to take their toll. The Changing of Imperialism. By 1914, Imperialism had begun to come at last to a turning point. The massive land grabs that had divided up Africa, given Britain such a huge empire, and led to the collapse of the Chinese Empire had finally run their course. There simply were very few places left on Earth containing massive amounts of land not already claimed by a western power. This was especially bad news to nations that were latecomers to the game of Imperialism, Germany and, to a lesser extent, Russia. Wilhelm II did not wish for Germany to miss out on the benefits of a colonial empire. Germany already had some territories in Africa, and after the Berlin Conference of 1885, they were major policy makers on the continent. However, Wilhelm II continually pushed for a larger role for Germany in Africa, leading ultimately to the Morocco Affair, and a heightening of tension. Turmoil in Russia. Russia was also undergoing immense changes. After three hundred years of Romanov rule, Russia was finally making a transition to a modern nation. However, the Romanov tsar, Nicholas II of Russia , was still clinging onto a good measure of authoritarian power. The struggle between Nicholas II and reform-minded progressives would eventually lead to the drama of the Russian Revolution. To make a bad situation worse, Russia was also in a bad geographic situation. Despite being the largest European power in terms of land area of their home nation, Russia was mostly poor and un-industrialized. Much of the nation was underdeveloped, and only slowly inching its way toward a more profitable existence. At the same time, Russia was dealing with an unfavorable political situation, already reeling from the loss of the Russo-Japanese War, as well as attempting to stay afoot of the fast-paced diplomacy of the west. The Sick Man of Europe. For several hundred years, the Ottoman Empire had been slowly collapsing under its own weight, watching helplessly as first one province and then another had broken away, or been stolen. Recently, in the Crimean War, the Ottomans had been forced to rely upon the aid of Britain and France to sustain itself in conflict against the Russians. The Empire had previously been called the "Sick Man of Europe", but prior to the war it was called the "Dying Man of Europe". Only sparse pieces of the Balkans remained in Ottoman control by 1914, and they were being encroached on from many fronts. The Austrians in the north clearly wanted to pacify provinces in the region, the Russians in the east wanted Istanbul itself to guarantee themselves a safe passage through to the Mediterranean from their Black Sea ports, and the people who lived in the Balkans were beginning to experience their own internal unrest. By 1914 it looked like conflict could erupt at any moment in the Balkans. Naval build up and the end of Splendid Isolation. In order to demonstrate their military capability, Germany embarked on a plan to build up her navy, constructing the High Seas Fleet, equipping it with the latest in military technology. This not only contributed to a rise in Germany's military power, but it also seriously alarmed Great Britain. Britain had long subscribed to the theory of "Splendid Isolation", under which Britain attempted to hold itself aloft from affair on the continent. Protected by the Royal Navy, the most powerful navy in Europe, Britain had remained inviolate to foreign powers for centuries; even Napoleon was unable to land an army on her shores. Under Splendid Isolation, Britain chose to abstain from permanent relationships with European powers and to continually work to maintain a balance between them, all the while protected from continental strife by her powerful navy. The construction of the German High Seas Fleet pushed Britain into a fury of shipbuilding, in an attempt to stay ahead of German production. The knowledge that they could no longer stand by in the distance and remain safe from European struggle, and the continuing threat created by German armament programs, propelled the British out of their self-imposed isolation. It also led to a souring of relations between both Britain and Germany. Assassination of Archduke Franz Ferdinand. On June 28, 1914, at approximately 11:00 am, Franz Ferdinand and his wife were killed in Sarajevo, the capital of the Austro-Hungarian province of Bosnia and Herzegovina, by Gavrilo Princip, a member of Young Bosnia and one of several (seven) assassins organized by The Black Hand (Crna Ruka). The event, known as the Assassination in Sarajevo, was one of the main triggers of World War I. War Breaks Out. Officially, the First World War began on June 28, 1914 in the Bosnian city of Sarajevo, with the assassination of Archduke Franz Ferdinand of the Austro-Hungarian Empire by Gavrilo Principe, a member of a secret Serbian society, The Black Hand, hoping to unite the Slavic speaking lands of the Austro-Hungarian Empire with the nearby Kingdom of Serbia. In retaliation, Austria, with the support of Germany, presented Serbia with a list of demands that would severely threaten the Kingdom's autonomy. The Austrian leaders had been waiting for this moment for several years, because they feared just the sort of Serbian groups that were now operating in Bosnia, and had been waiting for this chance to weaken Serbia for several years. After consultations with the Russians, Serbia rejected the demands, leading to war with Austria. Russia responded with a general mobilization, followed by Austria's ally Germany and Russia's ally France. The first stage of the war quickly escalated, with a general war breaking out between an alliance of Germany and Austria against Russia, France, and Serbia. The war presented the Germans with a special problem. Their own armies were scattered on the country's eastern and western borders against France to the west and Russia to the east, but the armies of France and Russia were concentrated against the Germans on their respective borders. In order to make the best out of this two front situation, the German generals began to carry out the Schlieffen Plan, developed by a German general in case of war with both France and Russia. The plan called for a quick and massive strike against the French while the massive Russian army was still mobilizing, hoping that their Austrian allies could stop the Russian advance long enough for them to finish off the French and move their troops by rail to defend the east. Unfortunately, the quickest way to strike the French capital, Paris, and knock the French out of the war involved a broad offensive through neutral Belgium. Great Britain, a nominal ally of France, promised to intervene in case Germany invaded Belgium, and declared war shortly after German forces crossed the border. The Germans initially expected the Belgians to put up very little resistance, but this proved to be incorrect and the longer than expected time required to defeat the Belgians allowed the French to regroup. While the Germans were pushing deep into Belgium, Serbian forces crossed the Danube in a daring attack against the Austrians. This offensive, like many others after it, failed, and the war zone along the Balkans would change very little during the first year. Meanwhile, the massive German offensive bearing down on France was beginning to run out of steam. First, the Russians scored several early victories against the Austrians and moved through Poland (then a Russian territory) on their way to attack Prussia and the vulnerable German capital, Berlin. The worried German generals withdrew several divisions to the eastern front, allowing the French to regroup and defeat the German lead elements at the Battle of the Marne, slightly more than 15 miles outside Paris. Though the German armies were stopped by the French, the Russian armies bearing down on Prussia were similarly defeated by German forces under Field Marshall Hindenburg at the Masurian Lakes, and then at Tannenberg. Though the Russian army was much larger than the German army, the Russian commander's decision to split his forces in a two-prong attack contributed to his defeat, and allowed the Germans to break apart the offensive piecemeal. Stalemate and Trench Warfare. Following these defeats, the war on both fronts bogged down. In the west, both French and British forces and the Germans built a massive series of trenches from the Swiss border to the North Sea to defend their positions. This period of "Trench Warfare" saw very little change in the battle lines, and several uses of poison gas by the Germans. With no major breakthroughs on either fronts, and furthermore the people in Russia were killed. German and British leaders looked to the Mediterranean to break the stalemate. This put the two remaining neutral powers, Italy and the Ottoman Empire (later Turkey) in a tough position. Before the war, the Italians had agreed to support Germany and Austria in case of war. However, British and French diplomats promised the Italians the Austrian territories adjacent to Venice if Italy declared war, which they did after the prodding of many Italian radicals, among them Mussolini. The Ottoman Empire also had to make a tough choice, because Britain was the Empire's traditional protector and Russia was the Empire's traditional enemy. Germany's offer of two battleships and Middle Eastern territories allowed the Turks to strike out at both simultaneously, beginning with a naval strike against the Russian naval base at Odessa. The Ottoman entry into the war encouraged neighboring Bulgaria to also enter the war in an alliance with Germany, leading to the rapid defeat and occupation of Serbia by the Austrians. Austria played an important part in the war and still is today a leading military nation. In 1915 the Ottomans launched an attack into Egypt in an attempt to capture the Suez Canal. The assault failed and the Ottomans retreated back into their empire. Once again in 1916 the Ottomans attempted to capture the canal, but this once again failed. This attack convinced the British to push their defence of the Canal further out, into the Sinai, and so starting in October, the British under Lieutenant General Sir Charles Dobell began operations into the Sinai desert and on to the border of Palestine. Initial efforts were limited to building a railway and a waterline across the Sinai. After several months building up supplies and troops, the British were ready for an attack. The first battle was the capture of Magdhaba on December 23 1916. This was a success, the fort was captured. In 1916, the Central Powers invaded Romania, and forced them to sign an unwilling peace. America Enters the War. By 1916, the two groups had been fighting for two years with neither side making significant gains. Food shortages had appeared in Germany (under blockade by Britain) and Russia, leading to much discontent. Responding to the British blockade, the Germans launched a naval offensive of their own, using submarines known as U-Boats to prey on allied shipping. The Lusitania. A British-American tourist cruise liner that was intentionally sunk by a German U-Boat. However, there was some ammunition onboard in the cargo area, and this was the German reason for sinking. The Zimmerman Telegram. A telegram from Germany to Mexico that encouraged Mexico to attack the United States. This telegram was provided to the United States by Great Britain and there has been some speculation on whether it was forged by Great Britain in order to get the previously neutral United States to join World War I Defeat of the Central Powers. Germany miscalculated by launching the u-boat campaign, which intended to win the war before the entry of USA. This miscalculation was a military suicide on the part of Germany as it led to the entry of USA. America with her vast resources entered the war on the side of allied forces leading them to a sweet victory against Germany.

World History/The Rise of Dictatorship and Totalitarianism. Quick Quiz Benito Mussolini and Fascism in Italy (1922-1939). Benito Mussolini, born into a poor blacksmith's family, was so named by his radically socialist father (his mother was a devout Catholic schoolteacher) after the executioner of a Mexican emperor. Shortly after becoming qualified as a teacher, Mussolini taught in a small school. Mussolini was a far-left socialist and advocated a violent revolution to overthrow the parliamentary monarchy within Italy and denounced nationalism. When World War I broke out in 1914, however, he broke with his party comrades when he celebrated the entry of his nation into the war – even though he had dodged the draft. Throughout the Great War, he fought earnestly to keep Italy involved, and, financed by large arms manufacturers and the British and French governments, operated a small, pro-war newspaper. When the war came to an end in 1919, Mussolini was quick to recognize the dissatisfaction of many of the homebound soldiers and countrymen concerning the Treaty of Versailles. In an effort to persuade Italy to enter the war on their side, the Allied Powers promised Italy significant territorial gains at the expense of the Austro-Hungarian Empire. The final settlement, however, was less favorable to Italian interests than that originally promised, and resulted in widespread malcontent regarding the post-war government. In March 1919, Mussolini created a radically nationalist and anti-communist party – Fasci Italiani di Combattimento. Mussolini, who loved the splendor and extravagance of Ancient Rome, adopted a Roman symbol of authority, the "fascio" (an axe wrapped in whipping rods) for his group of devotees. As inflation and economic decline spread throughout Europe and Italy following the war, factory workers began to go on strikes in northern Italy. In 1920, Mussolini’s group’s numbers were bolstered by ex-soldiers willing to break up these strikes. Mussolini marched 50,000 Fascist supporters (known as Blackshirts for their attire) in squads against the strikers and left-wing newspapers. The Blackshirts garnered their support from the financial contributions of industrialists and large landowners, who shared their anti-communist sentiments, but also believed that they could control the excesses of the Fascist party. The police often refused to stop the squads, allowing the Blackshirts freedom to inflict whatever damage they wished. The widespread destabilization of the previous social orders throughout Europe due to economic uncertainty in the aftermath of the war and the successful establishment of the Soviet Union as a socialist state led many to believe that democracy was weak and ineffectual, while monarchy was discredited as an oppressive and unresponsive system. A command economy was thought to be a progressive and scientific method of social organization. Fascism incorporated the futuristic and populist elements of Communist ideology, but also identified itself strongly with the nationalism that had created the modern European nation-states in the late 19th Century. Despite growing popularity and the introduction of proportional representation in the Parliament, Mussolini's party fared poorly at the polls, winning no seats in 1920 and only 35 in May 1921 (7% of the vote). The internal political situation however, swung in Mussolini's favor. The birth of the Communist Party of Italy, openly allied with Lenin's Soviet regime in Moscow, polarized Italian politics. Proportional representation caused stagnation in government, until a weak coalition finally came into place in February 1922. In October of that year, as Mussolini was giving one of his soon-to-be characteristic speeches from atop a balcony, he suddenly cried, “To Rome! To Rome!” The crowd of supporters, much to Mussolini’s surprise, echoed his cry. Blackshirts to the number of 40,000 organized to march on the capital. Mussolini, however, went into hiding, afraid of the impending collapse of his movement. When it became clear that the army would not oppose his action, however, Mussolini moved decisively. As Blackshirts began to occupy key posts in Rome on 27-28 October, the king, Victor Emmanuel III, to the chagrin of his elected cabinet, appointed Mussolini as Prime Minister so long as Mussolini halted the advance to Rome. Mussolini agreed. His word was not to be trusted, however, as he soon after marched on the city anyway, creating an incredible propaganda success for the Fascists. Over the next few years, he led a slow-motion coup d'état. By 1926, he had become the undisputed totalitarian dictator (“Il Duce,” or “the leader”) of Italy. Mussolini's regime embarked on a campaign of militarization and political maneuvering. First, he began to ready Italy for war. One of Mussolini’s driving ambitions was to restore the hegemony of the Roman Empire in a modern Italy. To that end, he encouraged couples to have as many children as possible as he organized large-scale expansions of the agricultural sector to feed them. He extended an olive branch to the Catholic Church by way of the Lateran Accords, which recognized papal authority over the Vatican and declared Catholicism the official religion of all of Italy, ending hundreds of years of estrangement. Mussolini seemed to have been a victim of his own propaganda as, in 1935, he deemed his newly-formed army strong enough to invade Ethiopia. The Italian army invaded from Italian-held Eritrea. The underestimation of the enemy proved fatal for thousands of ill-prepared Italians as the army met face-to-face with the “Lion of the Desert,” Omar Mukhtar (whose death by hanging at the hands of the Italians ended his twenty-year resistance). The poorly-armed Ethiopians were eventually defeated primarily due to terror tactics, such as poison gas and terror bombings. Mussolini’s sense of superiority did not seem hurt by his army's poor preparation, as, over the next few years, he became a close ally of Hitler's. In 1939, Mussolini signed the “Pact of Steel,” creating a formal alliance between Italy and Nazi Germany. Mussolini, while publicly effervescent, did not have the universal power and control enjoyed by Adolf Hitler and Joseph Stalin, a lack of gravitas which would later cost him his life. Nevertheless, Mussolini rode at the helm of the 20th century dictatorship, invented the terms Fascism and Totalitarianism, and pioneered the use of propaganda to control the masses in newspapers, posters, radio, and in movie cinemas. The Weimar Republic (1918-1933). Following the complete collapse of Germany's armed forces throughout the waning months of 1918, German generals and politicians desperately sought to surrender. The Allied Powers, however, would not negotiate with the autocratic Kaiser Wilhelm II, and insisted upon Germany to adopt a democratic government. In this disarray, Germany quickly fell along the slippery slope to revolution, appearing as though it might go the same direction as Russia – Marxist. After Kaiser Wilhelm II abdicated the throne on November 7, a new republic was declared, and a National Assembly convened at Weimar to circumvent the unrest in Berlin. The hastily-formed republican government took its name from the host city and surrendered. The Allied Powers, in turn, forced upon the defeated nation extremely harsh and punitive terms through the Treaty of Versailles. Clause 231 of the treaty, the so-called "war-guilt" clause, called for Germany to accept total and sole blame for the Great War (while, arguably, they merely joined) and to pay reparations to the “victimized” Allied Powers. Finally, it was established that Germany was to disband its air force permanently, and to have no more than 100,000 men in its armed forces. The Rhineland, along the Franco-German border, was demilitarized and put under French jurisdiction. The extremely valuable Saar region, home to most of Germany’s factories, was made autonomous. These harsh restrictions gave the fledgling Weimar Republic unwarranted disrespect. Many Germans had opposed the treaty, and it created large amounts of resentment within Germany. (Retrospectively, the Treaty of Versailles is seen as one of the most fundamental causes of the rise of Adolf Hitler and World War II.) The newfound lack of industry compounded the reparations Germany was forced to pay. To assuage its monetary woes, The Weimar Republic began to print paper money at exorbitant rates – rates so high, that, by 1923, the American Dollar was worth 4.2 trillion German Marks. Amidst the chaos of disappearing life savings and a tumultuous economy, Gustav Stresemann came to the forefront of Weimar Politik. Under his leadership, the Weimar Republic managed to regain marked stability in the period of 1923-1929. Peoples discontent about the Weimar government increased day by day. Hyperinflation was corrected, but Stresemann's death in 1929 and the catastrophic worldwide Great Depression the same year brought about the death of the Weimar Republic. This untimely fall led to the empowerment of a man who would vault Germany to an unprecedented world power, who would pursue the elimination of “undesirables” such as Jews and homosexuals, who would begin the second world war of the 20th Century. Hitler, who had been subverting many of his countrymen during the economically tumultuous 1920s, took advantage of the Weimar Republic’s fall. The Rise of Adolf Hitler in Germany (1914-1939). In August 1914, as the world took the fatal plunge into World War I, an unknown and unimportant young Austrian national named Adolf Hitler enlisted in the German Army. Born on April 20, 1889 into a troubled and strict Austrian family, Hitler was a failed artist and an ardent German nationalist (Austrians are ethnically German and indistinguishable from their cousins). His anti-semitic views already in place from his early life as a vagrant (he dropped out of high school and was refused admission to a Vienna art school), Hitler was eager to serve his adopted homeland. He had an exemplary record of service and received the prestigious Iron Cross, both First and Second Class, and also achieved the undistinguished rank of Corporal. Shocked and deeply angered by the German defeat in 1918, he personally put the sole blame on the so-called "November politicians" (referring to those who formed the Weimar Republic). He also put blame on the Jews for the downfall of Germany. After the war, Hitler remained in the army and after receiving intelligence and oratory training, became an intelligence official tasked with infiltrating political parties and reporting to his superiors on their activities. In March 1919, he was instructed to sit in on a meeting of the small nationalist German Worker's Party. He joined the party in September, and upon his discharge from the army in 1920, soon became the leader of the party which changed its name to the German National Socialist Worker's Party (NSDAP or Nazi for short, from its German name "Nationalsozialistische Deutsche Arbeiterpartei"). Over the next few years, Hitler's oratorical skills allowed the party to expand. It soon had its own private armed forces, known as the SA led by Ernst Rohm. Another important admirer was Erich Lundendorff, a Field Marshall from the First World War, whose help proved invaluable in setting up the Beer Hall Putsch. The Beer Hall Putsch and Mein Kampf (1923-1925). On November 8, 1923, Adolf Hitler and a group of SA raided a beer hall in Munich where the three most powerful politicians in Bavaria were giving speeches. Taking the men hostage, Hitler threatened them with death (and his own suicide) if they did not side with his intention to overturn Bavaria's government and then to march on Berlin. The men agreed (with little other choice). Hitler then made the colossal error of leaving the hall. He left Marshall Lundendorff in command, who upon the assurances of the three politicians that they only wished to return home to their families and would continue to support Hitler, allowed them to leave the hall. The men quickly denounced Hitler and mobilized the government's resistance to his "revolution". Adolf Hitler was enraged. He decided to march his SA the next morning against the Bavarian government. However, army regulars were already at the War Ministry when Hitler arrived and the rebellion was quickly scattered. Hitler was arrested and tried. He spoke so forcefully at his trial however, that the head judge had to harass the other two judges into even convicting him at all. He received a five year sentence. The abortive coup Hitler tried to carry out is referred to as the Beer Hall Putsch. In prison, Hitler dictated the book "Mein Kampf" (My Struggle) to his close friend and confidant, Rudolf Hess. The book was a savage "hymn of hate" denouncing Jews as "parasites" and laying down the foundation for the plan of military conquest Hitler would later attempt. It was all painfully clear: the rearmament of Germany, the invasion of Poland, the invasion of the Soviet Union; Hitler had written down for anyone who wished to read it his plan of action. Unfortunately, few non-Germans read the book, but all too many Germans did. Hitler was released after spending only eight months of his sentence, mostly because the authorities thought he was harmless. He found the Nazi party virtually moribund. In 1925, he formed the "Schutzstaffel" (SS) to be his personal body guard under the leadership of Heinrich Himmler. The Nazi Regime (1933-1939). Through the use of propaganda, Hitler became immensely popular among the German people. To end the depressions, Hitler followed a program of massive public works, including the infamous Autobahn, dams, roads, railroads, and civil improvements. His official announcement of rearmament in 1936 (although it had actually begun much earlier) stimulated the economy further, as it would in the United States during the Second World War. Culture evolved along a strict set of party rules. Men were the heads of work and home; a woman's place was as a cleaner and a mother. The Nazis encouraged large families to literally create men to serve in the army. The Nazis, through their policy of racism, wanted superiority in every sphere of life. When the Olympic Games came to Berlin in 1936, the Germans showed off their athletes in huge stadiums built for the purpose. Adolf Hitler practiced a policy of racial superiority of the Germans, whom he called Aryans, and people were sorted by the correct ethnic "purity". The ideal was the tall, blond, blue-eyed, muscular, and handsome Nordic youth (ironically, Hitler had brown hair). Hitler's regime followed a totalitarian policy; the SS and the secret police, the Gestapo, ruthlessly enforced loyalty to Hitler and rounded up the Nazi's enemies. In 1934, when the army had demanded as the price of its support the dissolution of the SA, Hitler had Ernst Rohm assassinated. Heinrich Himmler became the chief of secret police activities and the mastermind behind the terror. In 1935, the Nazis enacted the Nuremberg Laws, which placed extreme restrictions of Jews and their freedoms as human beings. The economic lives of the Jews were smashed. At this stage however, Hitler was not actively killing Jews but deporting them. The Nazis operated concentration camps at this time to deal primarily with political prisoners. The propaganda machine of the Nazis was similar to that of Stalin in the USSR. However, the Nazis, under propaganda minister Joseph Goebbels, used their propaganda to acquire not only acquiescence to Hitler's schemes, but also to convince the Germans of their policy of racial purity and antisemitism. Goebbels saw to it that, like in the Soviet Union, a picture of the Führer appeared in every building and home, and in many public places. Posters were one of the favorites of the Nazis. They also used the theater extensively to bring in support for the party's goals. Joseph Stalin takes power in the Soviet Union (1924-1934). When Vladimir Lenin died in 1924, he left a power vacuum behind in the wake of his death, centering on the continued use of the New Economic Policy (NEP). The primary contenders for political power were Joseph Stalin and Leon Trotsky. Leon Trotsky was a brilliant politician, and had been Commissar of War during the Civil War. He was a gifted orator and a dedicated Communist, especially to the cause of causing Marxist revolutions internationally, through the use of arms if need be. Ironically, Trotsky had originally been a member of the Menshevik faction of the Russian Social Workers Party, until Lenin, recognizing his genius, had won him over to the Bolshevik camp. Stalin, on the other hand, was a gifted organizer. He was referred to by many of his contemporaries in the party as "Comrade Index-card". However, Trotsky was obviously the more popular choice for the job as the head of the new communist state. Unfortunately for Trotsky, Stalin was also the party's General Secretary. Although primarily a bureaucratic job, the General Secretary actually held the most power in the party because he appointed regional and local party posts in government. Stalin was therefore in a position to appoint those who would support his bid for power. Stalin initially allied himself with the right and center factions of the Communist Party (if any part of a far-left party may be called "right") which supported the continued existence of the NEP. Allying himself with Lev Kamenev and Grigori Zinoviev, he threw his might against Trotsky, who was removed from his post as People's Commissar of War. Stalin now turned against Kamenev and Zinoviev, allying himself with Nicolai Bukharin. Trotsky was expelled from the Communist Party on November 12, 1927, and expelled from the Soviet Union in 1928. He eventually found his way to Mexico, where he was murdered in 1940, probably on Stalin's orders. Now Stalin turned on his allies again, abandoning Bukharin and calling for the abandonment of the NEP. By now, Stalin was the undisputed leading figure of the Communist Party. By the early 1930s, Stalin would truly become the dictator of the Soviet Union. The First Five-Year Plan and Collectivization (1927-1939). At the Fifteenth Congress of the Communist Party, Stalin openly advocated the end of the NEP and introduced a plan for rapidly industrializing the largely rural Soviet Union, remarking that the country was "fifty to one hundred years behind the advanced countries". The government then introduced Gosplan (The State General Planning Commission) which came up with basis for the Five-Year Plan, aimed to turn the country into a major industrial power within five years. The plan set ridiculously high quotas for development. Nonetheless, terrific economic growth was achieved, especially in the areas of coal and iron output. As a result, steel production grew exponentially. However, harsh penalties for not making quotas caused large-scale misrepresentation of growth to occur. Harsh totalitarian measures were introduced. Miners were expected to put in 16 and 18 hour work days, unheard of even the strictest parts of the major capitalist countries. Poor and hazardous working conditions caused countless deaths. Most of the massive industrial complexes constructed for the Five-Year Plan were built by slave-laborers, sentenced for trivial and often completely false crimes. Approximately 3.7 million people were sentenced for counter-revolutionary crimes, approximately 0.6 million were put to death, 0.7 million were expatriated, and 2.7 million were sent to forced labor camps (called the Gulag), often itself a death sentence. As another part of the Five-Year Plan, the government began to forcibly collectivize agriculture (that is, to create large-scale farms where peasants worked the land collectively). The state sought not only an increase in agricultural output, but also to export grain abroad, in order to gain financial capital to buy important technologies for the industrial parts of the Five-Year Plan. By 1936, 90% of the nation's farms had been collectivized. However, this was not done without cost. Peasants almost universally actively opposed collectivization. In the Ukraine, the peasants killed off livestock rather than give it to the authorities. Stalin was so incensed that he allowed a famine to occur which led to the deaths of millions of innocent Ukrainians. As a result, throughout the period of 1924-1953, agricultural output was generally low, not regaining output levels of the period of the NEP until 1940, and rising only marginally in the following years. In addition, Stalin saw fit to deal with richer peasant farmers (known as Kulaks) by deporting them to forced labor in Siberia. In practice however, any person critical of collectivization was deemed a Kulak and summarily deported. It is estimated that at least 2.5 million peasants (in addition to the above industrial workers) were deported, though the true number is believed to be much greater. The Great Purges and Politics in the Soviet Union (1930-1939). Throughout the period of collectivization and the Five-Year Plan, the Soviet government became increasingly tyrannical. Stalin, was extremely paranoid, began to turn on important members of the party he had once called supporters. In 1934, the last person who might have rivaled Stalin, Sergei Kirov, was shot in his office, most likely on Stalin's orders. Using the murder as a pretext, he began to engage in ruthless purges of the party membership. Ironically, most of the purged members were original members of the party and colleagues of Lenin, known as the Old Bolsheviks. Through a series of show trials, the defendants were sentenced to death and to forced labor in the Gulag. Often, after using torture to extract signed confessions and agreeing on lenient sentences for a confession of false charges in the court, Stalin would turn on his word and have the defendants executed. Zinoviev and Kamenev, Stalin's old allies, both met this fate. Through 1936-1937, a period known as the Great Terror, Stalin supposedly personally signed 40,000 death warrants. Stalin's dictatorship held incredible control over the general populace of the nation. Intense propaganda campaigns tried to indoctrinate the society with Communist thought. Stalin wanted to replace the national identities, such as the Russians, Ukrainians, or Belarussians, with the idea of a purely "Soviet" citizen. He also stipulated that all ethnic groups be treated equally. Under the Tsars, the Russians had been given preference. Now the heavy hand of Stalin was given equally to all nations. However, this did not prevent him from forcing the speakers of every language in the USSR to convert to the Cyrillic alphabet. Religion came under intense pressure as well, as atheism was the official policy of the state. Priests were rounded up and shipped to Gulag or executed. By the end of the terror, less than 1,000 churches remained out of at least 20,000. The NKVD, the Soviet secret police, hunted down citizens suspected of "counter-revolutionary" or "subversive" crimes. During the Great Terror, as many as 1 million people (the NKVD's own records admit 0.681 million) were executed for simply "opposing" Stalin's ideas and plans. False confessions were routinely extracted through torture and intimidation. The penalty for countless others (numbering by the most conservative estimates in the millions) was the Gulag. Fear was the order of the day in the Soviet Union. In addition, the Soviet state cultivated an extreme cult of personality around Stalin. Pictures of the dictator appeared at every street corner and in every building, including people's homes. School children ended the pledge of allegiance at the beginning of each day by saying "...and thank Comrade Stalin for this happy life". To be fair, social conditions did improve under Stalin. Unemployment fell to practically zero, and large bounds in the public health were introduced. However, there was no freedom whatsoever in Soviet society. Francisco Franco's Fascist Spain and the Spanish Civil War (1936-1945). Francisco Franco rose to power after the brutal turmoil of the Spanish Civil War. The conflict was between the residing leftist republican parties and the nationalist movement led by Franco. Some view the Spanish Civil War as a "dress rehearsal for World War II". The Struggle of dictatorship and democracy is evident in this conflict.

World History/Effects of the First World War. Direct Effects. The First World War left Europe in ruins. By the Treaty of Versailles, Germany, taking the blame for the war, was forced to pay massive reparations to the victorious Allies and lost lands to France and a restored Poland. The Austro-Hungarian Empire collapsed, with Czechoslovakia seceding, and other territories going to Poland, Serbia (now Yugoslavia), Italy, and Romania. These changes were made permanent by the Treaty of Saint-Germain, which also gave Yugoslavia the Austrian Adriatic Fleet. Bulgaria ceded small strips of territory to Romania, Yugoslavia, and Greece. The Great Influenza Epidemic. Most devastating, though, was a massive influenza outbreak that started on the front lines and spread throughout the world, carried by soldiers returning from the war. This outbreak killed more people in more countries than the war itself.

World History/Causes and course of the Second World War. Causes of World War II. France, Great Britain, and the U.S. had attained their wartime objectives in 1919. They had reduced Germany to a military cipher and had reorganized Europe and the world as they saw fit. The French and the British frequently disagreed on policy in the postwar period, however, and were unsure of their ability to defend the peace settlement. Disillusionment with war led to the practice of appeasement, or giving into an aggressor's demands to keep the peace. The U.S., disillusioned by the Europeans' failure to pay their war debts, retreated into isolationism. The Treaty of Versailles left many countries dissatisfied. Adverse conditions, such as reparations and unemployed veterans from World War I led to the circulation of new, radical ideas and solutions, such as fascism in Italy. This Fascist party, as Mussolini called it, later became a model for Hitler in Germany. The Failure of Peace Efforts. During the 1920s, attempts were made to achieve a stable peace. The first was President Woodrow Wilson's idea to establish the League of Nations (1920) as a forum in which nations could settle their disputes. The League's powers were limited to persuasion and various levels of moral and economic sanctions that the members were free to carry out as they saw fit. The United States never joined the League and Germany and the USSR were also never members. At the Washington Conference of 1921-2, the principal naval powers agreed to limit their navies according to a fixed ratio. The Locarno Conference (1925) produced a treaty guarantee of the German-French boundary and an arbitration agreement between Germany and Poland. In the Kellogg-Briande Pact (1928), 63 countries including all the Great Powers except the USSR, renounced war as an instrument of national policy and pledged to resolve all disputes among them "by pacific means." The signatories had agreed beforehand to exempt wars of "self-defense." The Rise of Fascism. One of the victors' stated aims in World War I had been "to make the world safe for democracy," and postwar Germany adopted a democratic constitution, as did most of the other states restored or created after the war. In the 1920s, however, the wave of the future appeared to be a form of nationalistic, militaristic totalitarianism known by its Italian name, fascism. It promised to minister to peoples' wants more effectively than democracy and presented itself as the one sure defense against communism. Benito Mussolini established the first Fascist, European dictatorship during the inter war period in Italy in 1922. Formation of the Axis Coalition. Adolf Hitler, the Leader of the German National Socialist (Nazi) party, preached a racist brand of fascism. Hitler promised to overturn the Versailles Treaty and secure additional "Lebensraum" ("living space") for the German people, who he contended deserve more as members of a superior race. In the early 1930s, the Great Depression hit Germany. The moderate parties could not agree on what to do about it, and large numbers of voters turned to the Nazis and Communists. In 1933 Hitler became the German Chancellor, and in a series of subsequent moves established himself as dictator. Japan did not formally adopt fascism, but the armed forces' powerful position in government enabled them to impose a similar type of totalitarianism. As dismantlers of the world status quo, the Japanese were well ahead of Hitler. They used a minor clash with Chinese troops near Mukden, also known as the Mukden or Manchurian crisis, in 1931 as a pretext for taking over all of Manchuria, where they proclaimed the puppet state of Manchukuo in 1932. In 1937-8 they occupied the main Chinese ports. Having denounced the disarmament clauses of the Versailles Treaty, created a new air force, and reintroduced conscription, Hitler tried out his new weapons on the side of right-wing military rebels in the Spanish civil war (1936-9). This venture brought him into collaboration with Mussolini who was also supporting the Spanish revolt after having seized (1935-6) Ethiopia in a small war. Treaties between Germany, Italy, and Japan in 1936-7 brought into being the Rome-Berlin-Tokyo Axis. For example, Japan and Germany signed the Anti-Comintern pact in 1936 and then Italy joined in 1937. This pact denounced communism and it showed their unity in the matter. The Axis thereafter became the collective term for those countries and their allies. German Aggression in Europe. Hitler launched his own expansionist drive with the annexation of Austria in March 1938. The way was clear: Mussolini supported him; and the British and French, overawed by German rearmament, accepted Hitler's claim that the status of Austria was an internal German affair. The U.S. had impaired its ability to act against aggression by passing a neutrality law that prohibited material assistance to all parties in foreign conflicts. In September 1938 Hitler threatened war to annex the western border area of Czechoslovakia, the Sudetenland and its 3.5. million ethnic Germans. The British Prime Minister Neville Chamberlain initiated talks that culminated at the end of the month in the Munich Pact, by which the Czechs, on British and French urging, relinquished the Sudetenland in return for Hitler's promise not to take any more Czech territory. Chamberlain believed he had achieved "peace for our time," but the word Munich soon implied abject and futile appeasement. Less than six months later, in March 1939, Hitler seized the remainder of Czechoslovakia. Alarmed by this new aggression and by Hitler's threats against Poland, the British government pledged to aid that country if Germany threatened its independence. A popular joke ran at the time: "A guarantee a day keeps Hitler away". France already had a mutual defense treaty with Poland. The turn away from appeasement brought the Soviet Union to the fore. Joseph Stalin, the Soviet dictator, had offered military help to Czechoslovakia during the 1938 crisis, but had been ignored by all the parties to the Munich Agreement. Now that war threatened, he was courted by both sides, but Hitler made the more attractive offer. Allied with Britain and France, the Soviet Union might well have had to fight, but all Germany asked for was its neutrality. In Moscow, on the night of August 23, 1939, the Nazi-Soviet Pact was signed. In the part published the next day, Germany and the Soviet Union agreed not to go to war against each other. A secret protocol gave Stalin a free hand in Finland, Estonia, Latvia, eastern Poland, and eastern Romania. The Worldwide Great Depression. The costs of carrying out World War I, as well as the costs to rebuild Western Europe after years of fighting, resulted in enormous debts on the part of the Western European powers to the United States. The enormous reparations put on Germany in the Treaty of Versailles also increased the debts. Coupled with ineffective governments in many of these European States (notably the Weinmar Republic, pre-Mussolini Italy and Socialist France) led to slow reconstruction and poor economic growth. With the crash of the New York Stock Market on 29 October, 1929, the United States recalled all foreign loans in the following days. Unable to repay these loans, the economies of the West collapsed, beginning the Great Depression. War in Europe. The German invasion of Poland on September 1, 1939 is regarded as the start of World War II. Due to official League of Nations law, France and the UK were obligated to intervene, but in reality did very little in a period known as the phony war. In Poland, however, fighting had begun. Germany was extremely successful in this war due to their new strategy known as blitzkrieg (meaning "lightning war"). This strategy involved the use of tanks, a relatively new technology at the time, to quickly overrun a country before they could set up their defenses properly. This strategy worked amazingly for Germany, with the German troops arriving near the Polish capitol of Warsaw in just 7 days. Germany and the USSR had made a nonaggression pact in the days leading up to the invasion, which was essentially an agreement to split eastern Europe between the two countries. The agreement was initially a shock to the world, as the two countries were governed by ideologies that were about as far apart from each other as possible. However, this fragile agreement did not last. Before that, though, the USSR used this opportunity to annex the Baltic states, parts of Romania, and tried to take land Finland in a disastrous campaign for the Russians known as the winter war. Germany then proceeded to take out Denmark and Norway in order to secure positions in the north sea. Then Germany shifted their attention to France. French strategy relied on using the Maginot line, a massive line of forts stretching the entirety of their border with Germany to protect their border with relatively few troops while positioning their best forces along the border with Belgium, as Germany had attacked through Belgium in the first world war. However, they left the Ardennes forest undefended, as they believed that the dense forest would provide enough of a natural barrier. Knowing this, Germany launched a daring attack that sent 50 tank divisions through the Ardennes. The Germans broke through, and managed to cut off the allied forces. The French forces there were wiped out, but they were able to defend long enough to let British forces escape through Dunkirk. But for France, all was lost. The bulk of their army had been wiped out, and within weeks France had to surrender. This was far from the end of French resistance, though, as aside from civilian resistance efforts, and forces fighting under the banner of "Free France" played a major role in the north African front in the coming years. In Europe, however, Germany had set up a puppet state called Vichy France in the south, while the north was fully annexed for defense purposes. Germany tried to make the odds seem as far in their favor as they could in the hopes that Britain would try to make peace, but the new Prime Minister Winston Churchill refused to give up. In order to take over the British Isles, Germany would first have to gain control of the English channel in both the air and sea to be able to land troops on the island. After intense air fighting over England that resulted in the bombing of major English cities, Britain stopped any chance of a naval invasion. The War in the Pacific. Mukden Incident and the Invasion of Manchuria (1931). After winning the Russo-Japanese War in 1905, Japan quickly became the dominant power in its region. Russia recognized Korea as a Japanese sphere of influence and removed all of its forces from there and Manchuria, the sparsely populated northeastern region of China. In 1910, Japan annexed Korea as its own with little protest or resistance. Still, Japan was a quickly growing country, both population-wise and economically. It founded the South Manchuria Railway company in Manchuria in 1906, and with that company was able to gain government-like control of the area. By 1931, the Depression had struck a blow to Japan. The government did little to help Japan's economy, and in the eyes of its citizens, was weak and powerless. Instead, the public favored the Japanese army, and soon the civilian government had lost control of its military. To the army, Manchuria seemed like an obvious solution to many of Japan's problems. Manchuria was vast and thinly populated, and would serve as excellent elbow room for an already overcrowded Japan. It was also thought that Manchuria was rich in forests, natural resources, and fertile land. The fact that the Japanese believed themselves to be far superior to the Chinese only moved Japan towards conflict faster. Additionally, the warlord of Manchuria went against Japanese expectations and declared his allegiance to a growing Chinese military movement. So, in 1931, the army staged an explosion at a section of railway near Mukden, a city in Manchuria, as a pretext to invade and annex China. Japan met little resistance, although it did not have support of its own government, and Manchuria was completely occupied by the end of the year. Japan subsequently set up the puppet state of Manchukuo to oversee the newly acquired region. The League of Nations vehemently protested Japan's aggression, but Japan then withdrew from it. Japan invades China (1937). The 1920s saw a weak and politically chaotic China. Warlords of the many provinces of China constantly feuded, and the central government was weak and decentralized, unable to do anything to stop conflict. In 1927 Chiang Kai-Shek gained control of the Kuomintang (the Chinese government) and its National Revolution Army. Chiang led an expedition to defeat southern and central Chinese warlords and gain the allegiance of northern warlords. He was successful, and he soon focused on what he perceived to be a greater threat than Japan, which was communism. But in 1937, the deposed warlord general of Manchuria kidnapped Chiang and refused to release him until he at least temporarily united with the communists against the Japanese threat. The Japanese army responded by staging the Battle of Lugou Bridge, which was supposed to provoke open war between China and Japan. It worked and the Sino-Japanese War began. The beginning of the conflict was marked by the Chinese strategy of giving up land in order to stall the Japanese. It is important to note that the Japanese was not to completely take over China; rather, the Japanese wanted to set up puppet governments in key regions that would protect and advance Japanese interests. The fall of Nanjing in the early stages of this conflict saw the beginning of Japanese war atrocities. 100,000-300,000 were killed in the six weeks after Nanjing was captured. Other war crimes committed included widespread rape, arson, and looting. Anti-Comintern Pact and Tripartite Pact. These were pacts between Germany, Italy, and Japan. The Anti-Comintern pact had been a pact that denounced communism and it was initially signed by Japan and Germany. However, later, as German and Italian relations improved, Italy also signed and this was made stronger later by the Rome-Berlin-Tokyo Axis in 1938. The Tripartite Pact also strengthened the alliance and it was basically a confirmation of the Rome-Berlin-Toyko Axis. Pearl Harbor and Simultaneous Invasions (early December 1941). On December 7, 1941, Japanese warplanes commanded by Vice Admiral Chuichi Nagumo carried out a surprise air raid on Pearl Harbor, Hawaii, the largest U.S. naval base in the Pacific. The Japanese forces met little resistance and devastated the harbor. This attack resulted in 8 battleships either sunk or damaged, 3 light cruisers and 3 destroyers sunk as well as damage to some auxiliaries and 343 aircraft either damaged or destroyed. 2408 Americans were killed including 68 civilians; 1178 were wounded. Japan lost only 29 aircraft and their crews and five midget submarines. However, the attack failed to strike targets that could have been crippling losses to the US Pacific Fleet such as the aircraft carriers which were out at sea at the time of the attack or the base's ship fuel storage and repair facilities. The survival of these assets have led many to consider this attack a catastrophic long term strategic blunder for Japan. The following day, the United States declared war on Japan. Simultaneously to the attack on Pearl Harbor, Japan also attacked U.S. air bases in the Philippines. Immediately following these attacks, Japan invaded the Philippines and also the British Colonies of Hong Kong, Malaya, Borneo and Burma with the intention of seizing the oilfields of the Dutch East Indies. Following the Japanese attack on Pearl Harbor, Germany declared war on the United States on December 11, 1941, even though it was not obliged to do so under the Tripartite Pact of 1940. Hitler made the declaration in the hopes that Japan would support him by attacking the Soviet Union. Japan did not oblige him, and this diplomatic move proved a catastrophic blunder which gave President Franklin D. Roosevelt the pretext needed for the United States joining the fight in Europe with full commitment and with no meaningful opposition from Congress. Some historians mark this moment as another major turning point of the war with Hitler provoking a grand alliance of powerful nations, most prominently the UK, the USA and the USSR, who could wage powerful offensives on both East and West simultaneously. Allied Defeats in the Pacific and Asia (late December 1941-1942). Simultaneous with the dawn raid on Pearl Harbor, the Japanese carried out an invasion of Malaya, landing troops at Kota Bharu on the east coast, supported by land based aircraft from bases in Vietnam and Taiwan. The British attempted to oppose the landings by dispatching Force Z, comprising the battleship HMS Prince of Wales and the battlecruiser HMS Repulse, with their escorting destroyers, from the naval base in Singapore, but this force was intercepted and destroyed by bombers before even reaching their objective. In a series of swift maneuvers down the Malay peninsula, thought by the British to be "impassable" to an invading force landing so far north, the Japanese advanced down to the Johor Straits at the southernmost tip of the peninsula by January 1942. The Japanese were even using tanks, which the British had incorrectly thought would not be able to penetrate the jungles. During a short two week campaign the Japanese crossed the Straits of Johor by amphibious assault and conducted a series of sharp battles, notably the battle of Kent Ridge when the Royal Malay Regiment put up a brave but futile effort to stem the tide. Singapore fell on February 15, 1942 and with its fall, Japan was now able to control the sea approaches from the Indian Ocean through the Malacca Straits. The natural resources of the Malay peninsula, in particular rubber plantations and tin mines, were now in the hands of the Japanese. Other Allied possessions, especially in the oil rich East Indies (Indonesia) were also swiftly captured, and all organised resistance effectively ceased, with attention now shifting to events closer to Midway, the Solomon Islands, the Bismark Sea and New Guinea. Allies Regroup and the Battle of Midway (1942). Following the attack on Pearl Harbour, the US military sought to strike back at Japan, and a plan was formulated to bomb Tokyo. As Tokyo could not be reached by land based bombers, it was decided to use an aircraft carrier to launch the attack close to Japanese waters. The Doolittle Raid was carried out by James H. (Jimmy) Doolittle and his squadron of B-25 medium bombers, launched from the USS Hornet. The raid achieved little strategically, but was a tremendous morale booster in the dark days of 1942. It also led to the decision by the Japanese military to attack the only logical base of the attackers, the tiny atoll of Midway. A powerful force of warships, with four large fleet carriers at its core (Akagi, Kaga, Hiryu and Soryu) attacked Midway. The US navy, with the aid of intercepted and decoded Japanese signals, were ready and launched a counter attack with the carriers USS Enterprise and USS Yorktown, destroying all four of the Japanese fleet carriers. This was a devastating blow to the Japanese and is considered the turning point of the Pacific War. The Japanese had largely roamed the Pacific Ocean, the South China Sea, the Malacca Straits and the Indian Ocean with impunity, launching raids from these same four carriers on Allied bases in these areas including Darwin, Colombo and along the Indian east coast. With the loss of these carriers and more importantly their cadre of irreplaceable hard core highly trained naval aviators, the Japanese could no longer maintain an effective offensive and became largely defensive from then on. Island Hopping (1943- Late 1944). Island hopping was a campaign of capturing key islands in the Pacific that were used as prerequisites, or stepping stones, to the next island with the eventual destination being Japan, rather than trying to capture every island under Japanese control. Allied forces often assaulted weaker islands first, while starving out the Japanese strongholds before attacking them. The Atomic Bomb (August 1945). On August 6, 1945, a lone B-29 bomber, named the Enola Gay, appeared over the skies of Hiroshima. Air raid sirens went off around the city and people ran for their shelters. However, minutes later, the all-clear symbol was given. Although it had been a seemingly harmless run, the B-29 had, in fact, dropped a single bomb (this bomb was called "Little Boy"). This bomb detonated about 1,900 feet over Hiroshima and leveled much of the city within a few thousandths of a second. Tens of thousands were killed immediately and many more would eventually die from the radiation poisoning. However, Japan did not surrender to the United States, so three days later, on August 9, 1945, a B-29 named Boxcar dropped an atom bomb on the city of Nagasaki (this bomb was called "Fat Man"). Although the bomb was actually more powerful than the Hiroshima bomb, the foggy weather conditions and the hilly terrain of Nagasaki somewhat shielded a portion of the city from the worst effects. This, in conjunction with other factors affecting the state of the war, led to a ceasefire with Japan, and surrender a month later.

World History/Consequences of the Second World War. The Second World War saw the most far-reaching transformation of world politics to date. The destructive technologies introduced during the war – foremost, the atomic bomb – made it very unlikely that a land-based conflict of similar scale and duration among the major nations could ever happen again, because of the potential for total destruction of all combatants. No advanced industrial nation has been invaded since 1945, and all wars since that time have been guerrilla conflicts in less-developed countries, conflicts involving less-developed countries with more advanced ones, or some combination of these two scenarios. From an economic standpoint, the war and its aftermath consumed much of the real and potential industrial production of the world over the period 1940–1960 (with the exception that the United States, its homeland untouched, was able to expand both its defense industries and its civilian economy very rapidly after 1945). Europe and Japan lay in ruins and would spend 15–20 years rebuilding the basis for economic life, with much assistance from the U.S. The Soviet Union and China, though victorious in the war, were also ravaged. Splitting of the world. Europe was split into two main camps by the "Iron Curtain", which divided Germany in half and separated Austria from Czechoslovakia and Hungary, and Italy from Yugoslavia. The Soviet Union absorbed eastern Poland, and "reassigned" large areas of German territory to Polish rule by way of compensation. Moscow intervened directly to install Communist parties in power in Poland, eastern Germany, Hungary and Czechoslovakia. Finland was able to keep its independence, but did not regain the lands it lost to the Soviets in the 1940 Winter War. Yugoslavia under Marshal Tito, already Communist, did not submit to direct influence from Moscow, choosing a more independent path and greatly angering Stalin. Elsewhere in the Balkans, Bulgaria, Romania and Albania also were brought into the Soviet bloc. To the west were the democracies allied to the USA: the UK, France, Italy, the Netherlands, Belgium, Norway, and West Germany. Washington became quite concerned, however, that local Communist parties might gain power in France, Italy and Greece in the late 1940s, given the battered state of the postwar European economy and the proximity of the Soviet Union. French leader Charles DeGaulle received strong backing from the U.S., and anti-Communist parties in Italy were heavily financed. In the end neither nation left the Western sphere of influence. In Asia, China, Vietnam, Korea and Mongolia were communist countries. Japan, first under occupation by the USA after WWII, had to reform its system – moving away from from militarism and expansionism and into democratic reforms. Military alliances were formed on both sides: First NATO, on April 4, 1949 in the USA geopolitical sphere and as a direct response due to the Cold War the Soviet Union (USSR), on May 14, 1955 created the Organization of Warsaw treaty, better known as Warsaw Pact. In an attempt to set up a body for possible dialog between Western, Eastern, and Developing countries and establish international law, the Organization of United Nations was established in 1945 by USA initiative. The failing of the League of Nations, also initiated by the USA was one of several precursor stages for WWII. Special consideration must be given to the geopolitical interests behind these organizations, especially who they favor. Even if ultimately, they are a stabilizing force. Other USA international initiatives include: the International Monetary Fund (IMF), the World Bank and more recently the World Trade Organization (WTO), that has its roots in the discussions to form the International Trade Organization (ITO) as an evolution from the General Agreement on Tariffs and Trade (GATT) of 1947.

Spanish/Lesson 6. Grammar - Object Pronouns. Direct Object Pronouns. While the subject of a sentence "initiates" an action (the verb), the direct object is the one that is "affected" by the action. A direct object pronoun is used to refer to the direct object of a previous sentence: The following table shows the six types of direct object pronouns: In spanish tú is used for informal situations, and usted must be used when a formal treatment is needed. Note: In Spain, "le" and "les" are used as the masculine direct object pronoun only when referring to people. If the antecedent of a direct object is masculine but non-human, "lo" or "los" are used instead. In most other Spanish speaking places, "lo" and "los" are used instead of "le" and "les". Indirect Object Pronouns. An indirect object is an object that would be asked for with "To whom...?" or "From whom...?". It is called "indirect" because it occurs usually together with a direct object which is affected directly by the action: The apple "is given" by the woman (direct). The boy gets the "given apple" (indirect - depends on the apple being given). Here is a table with all of the Spanish indirect object pronouns: Position Of Object Pronouns (Double Object Pronouns). So far we have only seen sentences with one object pronoun. If there is both a direct and an indirect object pronoun, the indirect pronoun usually comes first: Also, when both object pronouns are in the third person (either singular or plural), the indirect pronoun changes from le/les to se: In sentences that contain an infinitive or a participle, the object pronoun may be either placed before the conjugated verb or it maybe attached to the infinitive/participle: It is possible to have the two rules above working at the same time: A combination of direct and indirect pronouns that is attached to an infinitive/participle: Exercise:Object Pronouns Vocabulario (Vocabulary) - La comida (Food).   In Spain and some other countries, "comida" is the midday meal.   In other countries, for example Chile, "comida" is the last meal in the day. Instead of saying "desayuno, comida y cena" (Spain) or "desayuno, almuerzo y comida" (Chile, Colombia), it's safer to say "desayuno, almuerzo y cena". The word "comida" has several meanings Note that due to the pervasive influence of English, in many supermarkets there is a section called "Vegetales" instead of "Verduras". They mistranslate vegetable, forgetting that this is not the same as English vegetal (relating to plants).

Perl Programming. These books describe and explain Perl, a high-level, general-purpose, interpreted, dynamic programming language. Perl is noted for its idiomatically rich syntax, its extensive use of regular expressions and the large module archive CPAN.

Waves/1D Solutions. As you have learned in the previous sections, the linear waves you studied in the previous section tend to disperse. However, there are nonlinear waves described by nonlinear partial differential equations (PDE) which admits solutions with nondispersing wave packets. Here are two primary examples: Sine-Gordon. This is described by the PDE formula_1. The equation of a wave travelling along the positive x direction is given by y=0.25 x 0.001sin(500t-0.025x)determine the angular frequence

Calculus/Differentiation/Differentiation Defined. What is Differentiation? Differentiation is a process of finding a function that outputs the rate of change of one variable with respect to another variable. Informally, we may suppose that we're tracking the position of a car on a two-lane road with no passing lanes. Assuming the car never pulls off the road, we can abstractly study the car's position by assigning it a variable, formula_1 . Since the car's position changes as the time changes, we say that formula_1 is dependent on time, or formula_3 . This tells where the car is at each specific time. Differentiation gives us a function formula_4 which represents the car's speed, that is the rate of change of its position with respect to time. Equivalently, differentiation gives us the slope at any point of the graph of a non-linear function. For a linear function, of form formula_5 , formula_6 is the slope. For non-linear functions, such as formula_7 , the slope can depend on formula_1 ; differentiation gives us a function which represents this slope. The Definition of Slope. Historically, the primary motivation for the study of differentiation was the tangent line problem: for a given curve, find the slope of the straight line that is tangent to the curve at a given point. The word "tangent" comes from the Latin word "tangens", which means touching. Thus, to solve the tangent line problem, we need to find the slope of a line that is "touching" a given curve at a given point, or, in modern language, that has the same slope. But what exactly do we mean by "slope" for a curve? The solution is obvious in some cases: for example, a line formula_9 is its own tangent; the slope at any point is formula_10 . For the parabola formula_11 , the slope at the point formula_12 is formula_13 ; the tangent line is horizontal. But how can you find the slope of, say, formula_14 at formula_15 ? This is in general a nontrivial question, but first we will deal carefully with the slope of lines. The Slope of a Line. The slope of a line, also called the gradient of the line, is a measure of its inclination. A line that is horizontal has slope 0, a line from the bottom left to the top right has a positive slope and a line from the top left to the bottom right has a negative slope. The slope can be defined in two (equivalent) ways. The first way is to express it as how much the line climbs for a given motion horizontally. We denote a change in a quantity using the symbol formula_16 (pronounced "delta"). Thus, a change in formula_1 is written as formula_18 . We can therefore write this definition of slope as: An example may make this definition clearer. If we have two points on a line, formula_20 and formula_21 , the change in formula_1 from formula_23 to formula_24 is given by: Likewise, the change in formula_26 from formula_23 to formula_24 is given by: This leads to the very important result below. Alternatively, we can define slope trigonometrically , using the tangent function: where formula_31 is the angle from the rightward-pointing horizontal to the line, measured counter-clockwise. If you recall that the tangent of an angle is the ratio of the y-coordinate to the x-coordinate on the unit circle, you should be able to spot the equivalence here. Of a graph of a function. The graphs of most functions we are interested in are not straight lines (although they can be), but rather curves. We cannot define the slope of a curve in the same way as we can for a line. In order for us to understand how to find the slope of a curve at a point, we will first have to cover the idea of tangency. Intuitively, a tangent is a line which "just" touches a curve at a point, such that the angle between them at that point is 0. Consider the following four curves and lines: A secant is a line drawn through two points on a curve. We can construct a definition of a tangent as the limit of a secant of the curve taken as the separation between the points tends to zero. Consider the diagram below. As the distance formula_32 tends to 0, the secant line becomes the tangent at the point formula_33 . The two points we draw our line through are: and As a secant line is simply a line and we know two points on it, we can find its slope, formula_36 , using the formula from before: (We will refer to the slope as formula_36 because it may, and generally will, depend on formula_32 .) Substituting in the points on the line, This simplifies to This expression is called the difference quotient. Note that formula_32 can be positive or negative — it is perfectly valid to take a secant through any two points on the curve — but cannot be formula_13 . The definition of the tangent line we gave was not rigorous, since we've only defined limits of "numbers" — or, more precisely, of functions that output numbers — not of "lines". But we "can" define the "slope" of the tangent line at a point rigorously, by taking the limit of the slopes of the secant lines from the last paragraph. Having done so, we can "then" define the tangent line as well. Note that we cannot simply set formula_32 to 0 as this would imply division of 0 by 0 which would yield an undefined result. Instead we must find the limit of the above expression as formula_32 tends to 0: This last equation is just the point-slope form for the line through formula_46 with slope formula_10. Exercises. Solutions The Rate of Change of a Function at a Point. Consider the formula for average velocity in the formula_1 direction, formula_49 , where formula_18 is the change in formula_1 over the time interval formula_52 . This formula gives the average velocity over a period of time, but suppose we want to define the instantaneous velocity. To this end we look at the change in position as the change in time approaches 0. Mathematically this is written as: formula_53 , which we abbreviate by the symbol formula_4 . (The idea of this notation is that the letter formula_55 denotes change.) Compare the symbol formula_55 with formula_16 . The idea is that both indicate a difference between two numbers, but formula_16 denotes a finite difference while formula_55 denotes an infinitesimal difference. Please note that the symbols formula_60 and formula_61 have no rigorous meaning on their own, since formula_62 , and we can't divide by 0. The Definition of the Derivative. You may have noticed that the two operations we've discussed — computing the slope of the tangent to the graph of a function and computing the instantaneous rate of change of the function — involved exactly the same limit. That is, the slope of the tangent to the graph of formula_67 is formula_68 . Of course, formula_68 can, and generally will, depend on formula_1 , so we should really think of it as a "function" of formula_1 . We call this process (of computing formula_68) differentiation. Differentiation results in another function whose value for any value formula_1 is the slope of the original function at formula_1 . This function is known as the derivative of the original function. Since lots of different sorts of people use derivatives, there are lots of different mathematical notations for them. Here are some: Most of the time the brackets are not needed, but are useful for clarity if we are dealing with something like formula_83 , where we want to differentiate the product of two functions, formula_84 and formula_85 . The first notation has the advantage that it makes clear that the derivative is a function. That is, if we want to talk about the derivative of formula_76 at formula_87 , we can just write formula_88 . In any event, here is the formal definition: Examples. Example 1 The derivative of formula_89 is no matter what formula_1 is. This is consistent with the definition of the derivative as the slope of a function. Example 2 What is the slope of the graph of formula_92 at formula_93 ? We can do it "the hard (and imprecise) way", "without" using differentiation, as follows, using a calculator and using small differences below and above the given point: When formula_94 , formula_95 . When formula_96 , formula_97 . Then the difference between the two values of formula_1 is formula_99 . Then the difference between the two values of formula_26 is formula_101 . Thus, the slope formula_102 at the point of the graph at which formula_103 . But, to solve the problem precisely, we compute We were lucky this time; the approximation we got above turned out to be exactly right. But this won't always be so, and, anyway, this way we didn't need a calculator. In general, the derivative of formula_7 is Example 3 If formula_105 (the absolute value function) then formula_106 , which can also be stated as Finding this derivative is a bit complicated, so we won't prove it at this point. Here, formula_76 is not smooth (though it is continuous) at formula_109 and so the limits formula_110 and formula_111 (the limits as 0 is approached from the right and left respectively) are not equal. From the definition, formula_112 , which does not exist. Thus, formula_113 is undefined, and so formula_75 has a discontinuity at 0. This sort of point of non-differentiability is called a cusp. Functions may also not be differentiable because they go to infinity at a point, or oscillate infinitely frequently. Understanding the derivative notation. The derivative notation is special and unique in mathematics. The most common notation for derivatives you'll run into when first starting out with differentiating is the Leibniz notation, expressed as formula_68 . You may think of this as "rate of change in formula_26 with respect to formula_1" . You may also think of it as "infinitesimal value of formula_26 divided by infinitesimal value of formula_1" . Either way is a good way of thinking, although you should remember that the precise definition is the one we gave above. Often, in an equation, you will see just formula_120 , which literally means "derivative with respect to x". This means we should take the derivative of whatever is written to the right; that is, formula_121 means formula_68 where formula_123 . As you advance through your studies, you will see that we sometimes pretend that formula_124 and formula_60 are separate entities that can be multiplied and divided, by writing things like formula_126 . Eventually you will see derivatives such as formula_127 , which just means that the input variable of our function is called formula_26 and our output variable is called formula_1 ; sometimes, we will write formula_130 , to mean the derivative with respect to formula_26 of whatever is written on the right. In general, the variables could be anything, say formula_132 . All of the following are equivalent for expressing the derivative of formula_11 Exercises. Solutions Differentiation Rules. The process of differentiation is tedious for complicated functions. Therefore, rules for differentiating general functions have been developed, and can be proved with a little effort. Once sufficient rules have been proved, it will be fairly easy to differentiate a wide variety of functions. Some of the simplest rules involve the derivative of linear functions. Derivative of a constant function. For any fixed real number formula_139 , Intuition. The graph of the function formula_140 is a horizontal line, which has a constant slope of 0. Therefore, it should be expected that the derivative of this function is zero, regardless of the values of formula_1 and formula_139 . Proof. The definition of a derivative is Let formula_140 for all formula_1 . (That is, formula_84 is a constant function.) Then formula_147 . Therefore Let formula_149 . To prove that formula_150 , we need to find a positive formula_151 such that, for any given positive formula_152 , formula_153 whenever formula_154 . But formula_155 , so formula_153 for any choice of formula_151 . Examples. Note that, in the second example, formula_160 is just a constant. Derivative of a linear function. For any fixed real numbers formula_10 and formula_139 , The special case formula_163 shows the advantage of the formula_120 notation—rules are intuitive by basic algebra, though this does not constitute a proof, and can lead to misconceptions to what exactly formula_60 and formula_124 actually are. Intuition. The graph of formula_9 is a line with constant slope formula_10. Proof. If formula_169 , then formula_170. So, Constant multiple and addition rules. Since we already know the rules for some very basic functions, we would like to be able to take the derivative of more complex functions by breaking them up into simpler functions. Two tools that let us do this are the constant multiple rule and the addition rule. The Constant Rule. For any fixed real number formula_139 , The reason, of course, is that one can factor formula_139 out of the numerator, and then of the entire limit, in the definition. The details are left as an exercise. Example We already know that Suppose we want to find the derivative of formula_174 Another simple rule for breaking up functions is the addition rule. The Addition and Subtraction Rules. Proof From the definition: By definition then, this last term is formula_175 Example What is the derivative of formula_176 ? The fact that both of these rules work is extremely significant mathematically because it means that differentiation is linear. You can take an equation, break it up into terms, figure out the derivative individually and build the answer back up, and nothing odd will happen. We now need only one more piece of information before we can take the derivatives of any polynomial. The Power Rule. This has been proved in an example in Derivatives of Exponential and Logarithm Functions where it can be best understood. For example, in the case of formula_177 the derivative is formula_178 as was established earlier. A special case of this rule is that formula_179 . Since polynomials are sums of monomials, using this rule and the addition rule lets you differentiate any polynomial. A relatively simple proof for this can be derived from the binomial expansion theorem. This rule also applies to fractional and negative powers. Therefore Derivatives of polynomials. With these rules in hand, you can now find the derivative of any polynomial you come across. Rather than write the general formula, let's go step by step through the process. The first thing we can do is to use the addition rule to split the equation up into terms: We can immediately use the linear and constant rules to get rid of some terms: Now you may use the constant multiplier rule to move the constants outside the derivatives: Then use the power rule to work with the individual monomials: And then do some algebra to get the final answer: These are not the only differentiation rules. There are other, more advanced, differentiation rules, which will be described in a later chapter. Exercises. Solutions

Waves/Fourier Transforms. Fourier Transform. So far, you've learned how to superimpose a finite number of sinusoidal waves. However, a wave in general can't be expressed as the sum of a finite number of sines and cosines. Fortunately, we have a theorem called Fourier's theorem which basically states that under certain technical assumptions, any function, f(x) is equal to an integral over sines and cosines. In other words, Now, if we're given the wave function when t=0, φ(x,0) and the velocity of each sine wave as a function of its wave number, v(k), then we can compute φ(x,t) for any t by taking the inverse Fourier transform of φ(x,0) conducting a phase shift, and then taking the Fourier transform. Fortunately, the inverse Fourier transform is very similar to the Fourier transform itself. This tells us that, since waves which are very spread out, like the sine wave, have a narrow range of wave numbers, wave functions whose wave numbers are very spread out will only be significant at a narrow range of positions.

Organic Chemistry/Introduction to reactions/How to write organic reactions. Writing General Chemistry Reactions. In organic chemistry, a reaction may be written precisely as it is for general chemistry if only a basic amount of information is needed. For example, when a haloalkane is turned into an alkene, the reaction may be written: codice_1 Unfortunately, this method of notation does not tell anyone very much about the reaction, and it takes expertise to know exactly what is going on. A new student to organic chemistry probably would not notice that the product molecule contains one site of unsaturation due to a double bond between carbon atoms number one and number two. Because it is so general, this notation is good for general chemistry, but organic chemistry requires more precision. For most students, common practices in writing organic reactions will be different than used in general chemistry. Differences in Organic Chemistry Notation. Organic chemistry reactions are often not written as balanced equations. This is because many organic chemists - who are just as lazy as anyone else - tend to be more interested in the "organic product" of a reaction than in anything else going on in the reaction. Side products are often ignored, and just as often catalysts and solution notation may be highly abbreviated or left out altogether. As you gain familiarity with organic chemistry you will come to understand just what may be abbreviated or left out, but in the beginning this can be a source of frustration. Another difference is that modified Lewis drawings of molecules are often used instead of molecular formulas. This makes sense due to the fact that organic molecules are often rather large in size and complicated in structure, so that they can be more easily understood in the form of a drawing as opposed to a word-formula. A two-dimensional drawing reveals some of the three-dimensional shape of the molecule, but when necessary even three-dimensional drawings are used to depict reactants and products. <br> <br> Working with the above drawing of a molecule may be difficult, but it is still far easier than using its name, or attempting to guess at the structure and functionality of a molecule using just its chemical formula of codice_2. Examples of Organic Chemistry Notation. Typically organic chemistry molecules are drawn as modified Lewis structures. If you remember, a Lewis structure uses lines to connect chemical symbols together, illustrating a covalent bond, and also uses dots to represent non-bond electrons. This is shown in the diagram below of carbon dioxide. The drawing illustrates the four electrons of carbon participating in two double bonds with two oxygen atoms, and also the non-bonding electron pairs for each atom of oxygen. In organic chemistry, there are a lot of carbons in every molecule, generally, so organic chemists by convention do not draw every single carbon in every molecule. The same is true of hydrogens attached to the carbons; it is twice the annoyance to draw thirty hydrogens in a fatty acid than it is to draw the fifteen carbons. Therefore, in organic chemistry, carbon atoms are assumed to be wherever a line or line segment begins or ends. Furthermore, enough hydrogen atoms are assumed to be attached to any carbon not marked with a + or - sign (indicating an ionic charge) to bring that carbon's total number of bonds to four. At first this notation may be confusing, but the shorthand method rapidly proves its worth.

Computer Programming. Computer programming is the craft of writing useful, maintainable, and extensible source code which can be interpreted or compiled by a computing system to perform a meaningful task. Programming a computer can be performed in one of numerous languages, ranging from a higher-level language to writing directly in low-level machine code (that is, code that more directly controls the specifics of the computer's hardware) all the way down to writing microcode (which does directly control the electronics in the computer). Using programming languages and markup languages (such as XHTML and XForms) require some of the same skills, but using markup languages is generally not considered "programming." Nevertheless, many markup languages allow inclusion of scripts, e.g. many HTML documents contain JavaScript. There are exceptions where markup languages do represent programming such as SuperX++ (http://xplusplus.sourceforge.net/) and o:XML (http://www.o-xml.org/) Computer programming is one part of a much larger discipline known as software engineering, which includes several different aspects of making software including design, construction and quality control. The subject of this book is software construction, that is, programming. Computer programming is also a useful skill (though not always necessary) for people who are interested in . Whereas software engineering is interested specifically in making software, computer science tends to be oriented towards more theoretical or mathematical problems. Getting started. Many people think they must choose a specific programming language in order to become a programmer, believing that they can only do that language. They ask themselves, "Should I be a C programmer or a Java programmer?" That's completely the wrong question. The right question is "How can I become a good programmer?" Unfortunately the employment market has contributed greatly to misconceptions about computer programming by companies advertising for employees with a specific (therefore limited) computer language skill-set and responses being handled by human resources(HR), without someone with a programming background. There are a few points one can make about what a good programmer knows about specific computer languages. First - many languages are based on the same fundamental building blocks. Learning a language should be seen more as a way of acquiring those concepts than language or machine specific techniques. Second - good programmers are generally competent in more than one language because it is naturally interesting and useful to find different ways of solving problems. It is not necessary to master many different languages or even more than one—a programmer could excel in one language and have only a vague working idea how to program others. It is useful to know many different methods for solving computer problems, also known as algorithms. An algorithm is a list of well-defined instructions for completing a task, and knowing several languages means having the ability to list the computer instructions in many different ways. Since computer programming languages have so much in common, it is generally easy to learn a new programming language once you have mastered another. So how do you get started? One reasonable technique would be to just pick a language and run with it. Unfortunately, we cannot suggest what the right computer language might be for all people for all purposes. Ask ten programmers what language you should learn and you will get ten different responses. Given the collaborative nature of this wikibook, you'll probably get as many responses as there are programming language books on the site. Families of languages. There is a common misconception by people unfamiliar with computer programming that all programming languages are essentially the same. In one sense this is true because all digital electronic computers translate programming languages into strings of ones and zeros called binary, or Machine code. While mainstream, personal computer languages tend to be derived from a specific tradition and are very similar (hence the popularity of this misconception), some languages fall into different paradigms which provide for a radically different programming experience. Programming in Java is quite different from programming in , which is quite different from programming in Haskell or Prolog or Forth, etc. In the American Scientist article The Semicolon Wars, Brian Hayes classifies languages into four categories: imperative, object-oriented, functional, and declarative. Imperative and object-oriented languages tend to be used in the mainstream, whereas functional and declarative languages tend to be used in academic settings. Functional and declarative programming enthusiasts might argue that the paradigms are 20 years ahead of the mainstream and superior in many respects; however, mainstream language advocates would probably counter that such paradigms are hard to learn, or not very practical for their own unpopularity, among other things. We do not make any claims about who is right on this matter, but at the very least, we will suggest that building familiarity with the four major paradigms is an extremely valuable exercise. When it comes to computers, all things are made, and function primarily by, programming. Although programming is an essential part of the functionality of any computer or application, not all programming languages are the same. In fact, they are very different from one another with different uses, functionality, and different levels of complexity. A programming language, in the most basic way, is a set of rules or guidelines that is used to write the computer programs. Even though you are writing the program, you may need a certain type of software or program for the language that you use. There are many different types of programming languages that can be used and each has a different set of rules. Programming has two basic categories. There are low-level and high-level languages, the difference between the two is that low-level languages often use 0s and 1s, and this works because it gives the computer the ability to quickly understand what needs to be done or executed. High level languages are easier to write because they are much closer to the English language and are much more flexible to write with, although there are also different levels of this readability as well and different categories of these languages that can be written. A few examples would be Visual Basic, C++, and Java. Common concepts. Programming languages tend to have many general concepts in common. One can examine the recurring concepts and how they are expressed in various languages in the following table. To see a comparison of syntax in various programming languages, see these "Hello World" examples. For a list including various computer languages arranged together by syntax terms and patterns, see . Programming skills. Computer programming is really just about solving problems. It turns out that a large number of the problems you encounter in the real world are really just special cases of a more general problem. Luckily for you, many of these problems have been studied by computer scientists for a very long time, sometimes leading to provably unbeatable solutions, or sometimes solutions which are "good enough" for every day needs. In short, learning a language gives you skills, but learning data structures and algorithms shows you how to use these skills wisely. History of programming. Specific languages. The following languages deserve special mention, being significant languages in the development of structured programming languages and object-oriented programming. They are worth understanding for the concepts they introduced. Additional Information. Editors. An editor is simply a text program like Notepad. It is said that a programmer's best friend is the editor. A good editor is lightweight, has only essential tools and should support syntax highlighting for your language. Examples of good editors for which we have teaching books are : For more text editors, see Wikipedia's . Popular libraries. Unix native Windows "native" Cross platform

C Programming/Variables. Like most programming languages, C uses and processes variables. In C, variables are human-readable names for the computer's memory addresses used by a running program. Variables make it easier to store, read and change the data within the computer's memory by allowing you to associate easy-to-remember labels for the memory addresses that store your program's data. The memory addresses associated with variables aren't determined until after the program is compiled and running on the computer. At first, it's easiest to imagine variables as placeholders for values, much like in mathematics. You can think of a variable as being equivalent to its assigned value. So, if you have a variable "i" that is initialized (set equal) to 4, then it follows that "i + 1" will equal "5". However, a skilled C programmer is more mindful of the invisible layer of abstraction going on just under the hood: that a variable is a stand-in for the memory address where the data can be found, not the data itself. You will gain more clarity on this point when you learn about pointers. Since C is a relatively low-level programming language, before a C program can utilize memory to store a variable it must claim the memory needed to store the values for a variable. This is done by declaring variables. Declaring variables is the way in which a C program shows the number of variables it needs, what they are going to be named, and how much memory they will need. Within the C programming language, when managing and working with variables, it is important to know the "type" of variables and the "size" of these types. A type’s size is the amount of computer memory required to store one value of this type. Since C is a fairly low-level programming language, the size of types can be specific to the hardware and compiler used – that is, how the language is made to work on one type of machine can be different from how it is made to work on another. All variables in C are typed. That is, every variable declared must be assigned as a certain type of variable. Declaring, Initializing, and Assigning Variables. Here is an example of declaring an integer, which we've called some_number. (Note the semicolon at the end of the line; that is how your compiler separates one program "statement" from another.) int some_number; This statement tells the compiler to create a variable called codice_1 and associate it with a memory location on the computer. We also tell the compiler the type of data that will be stored at that address, in this case an integer. Note that in C we must specify the type of data that a variable will store. This lets the compiler know how much total memory to set aside for the data (on most modern machines an codice_2 is 4 bytes in length). We'll look at other data types in the next section. Multiple variables can be declared with one statement, like this: int anumber, anothernumber, yetanothernumber; In early versions of C, variables had to be declared at the beginning of a block. In C99 it is allowed to mix declarations and statements arbitrarily – but doing so is not usual, because it is rarely necessary, some compilers still don’t support C99 (portability), and it may, because it is uncommon yet, irritate fellow programmers (maintainability). After declaring variables, you can assign a value to a variable later on using a statement like this: some_number = 3; The assignment of a value to a variable is called "initialization". The above statement directs the compiler to insert an integer representation of the number "3" into the memory address associated with codice_1. We can save a bit of typing by declaring "and" assigning data to a memory address at the same time: int some_new_number = 4; You can also assign variables to the value of other variable, like so: some_number = some_new_number; Or assign multiple variables the same value with one statement: anumber = anothernumber = yetanothernumber = 8; This is because the assignment x = y returns the value of the assignment, y. For example, some_number = 4 returns 4. That said, x = y = z is really a shorthand for x = (y = z). Naming Variables. Variable names in C are made up of letters (upper and lower case) and digits. The underscore character ("_") is also permitted. Names must not begin with a digit. Unlike some languages (such as Perl and some BASIC dialects), C does not use any special prefix characters on variable names. Some examples of valid (but not very descriptive) C variable names: foo Bar BAZ foo_bar _foo42 _ QuUx Some examples of invalid C variable names: 2foo (must not begin with a digit) my foo (spaces not allowed in names) $foo ($ not allowed -- only letters, and _) while (language keywords cannot be used as names) As the last example suggests, certain words are reserved as keywords in the language, and these cannot be used as variable names. It is not allowed to use the same name for multiple variables in the same scope. When working with other developers, you should therefore take steps to avoid using the same name for global variables or function names. Some large projects adhere to naming guidelines to avoid duplicate names and for consistency. In addition there are certain sets of names that, while not language keywords, are reserved for one reason or another. For example, a C compiler might use certain names "behind the scenes", and this might cause problems for a program that attempts to use them. Also, some names are reserved for possible future use in the C standard library. The rules for determining exactly what names are reserved (and in what contexts they are reserved) are too complicated to describe here, and as a beginner you don't need to worry about them much anyway. For now, just avoid using names that begin with an underscore character. The naming rules for C variables also apply to naming other language constructs such as function names, struct tags, and macros, all of which will be covered later. Literals. Anytime within a program in which you specify a value explicitly instead of referring to a variable or some other form of data, that value is referred to as a literal. In the initialization example above, 3 is a literal. Literals can either take a form defined by their type (more on that soon), or one can use hexadecimal (hex) notation to directly insert data into a variable regardless of its type. Hex numbers are always preceded with "0x". For now, though, you probably shouldn't be too concerned with hex. The Four Basic Data Types. In Standard C there are four basic data types. They are codice_2, codice_5, codice_6, and codice_7. The codice_2 type. The int type stores integers in the form of "whole numbers". An integer is typically the size of one machine word, which on most modern home PCs is 32 bits (4 octets). Examples of literals are whole numbers (integers) such as 1, 2, 3, 10, 100... When int is 32 bits (4 octets), it can store any whole number (integer) between -2147483648 and 2147483647. A 32 bit word (number) has the possibility of representing any one number out of 4294967296 possibilities (2 to the power of 32). If you want to declare a new int variable, use the int keyword. For example: int numberOfStudents, i, j = 5; In this declaration we declare 3 variables, numberOfStudents, i and j, j here is assigned the literal 5. The codice_5 type. The codice_5 type is capable of holding any member of the execution character set. It stores the same kind of data as an codice_2 (i.e. integers), but typically has a size of one byte. The size of a byte is specified by the macro codice_12 which specifies the number of bits in a char (byte). In standard C it never can be less than 8 bits. A variable of type codice_5 is most often used to store character data, hence its name. Most implementations use the ASCII character set as the execution character set, but it's best not to know or care about that unless the actual values are important. Examples of character literals are 'a', 'b', '1', etc., as well as some special characters such as 'codice_14' (the null character) and 'codice_15' (newline, recall "Hello, World"). Note that the codice_5 value must be enclosed within single quotations. When we initialize a character variable, we can do it two ways. One is preferred, the other way is bad programming practice. The first way is to write: char letter1 = 'a'; This is "good" programming practice in that it allows a person reading your code to understand that letter1 is being initialized with the letter 'a' to start off with. The second way, which should "not" be used when you are coding letter characters, is to write: char letter2 = 97; /* in ASCII, 97 = 'a' */ This is considered by some to be extremely bad practice, if we are using it to store a character, not a small number, in that if someone reads your code, most readers are forced to look up what character corresponds with the number 97 in the encoding scheme. In the end, codice_17 and codice_18 store both the same thing – the letter 'a', but the first method is clearer, easier to debug, and much more straightforward. One important thing to mention is that characters for numerals are represented differently from their corresponding number, i.e. '1' is not equal to 1. In short, any single entry that is enclosed within 'single quotes'. There is one more kind of literal that needs to be explained in connection with chars: the string literal. A string is a series of characters, usually intended to be displayed. They are surrounded by double quotations (" ", not ' '). An example of a string literal is the "Hello, World!\n" in the "Hello, World" example. The string literal is assigned to a character array, arrays are described later. Example: const char MY_CONSTANT_PEDANTIC_ITCH[] = "learn the usage context.\n"; printf("Square brackets after a variable name means it is a pointer to a string of memory blocks the size of the type of the array element.\n"); The codice_6 type. codice_6 is short for floating point. It stores inexact representations of real numbers, both integer and non-integer values. It can be used with numbers that are much greater than the greatest possible codice_2. codice_6 literals must be suffixed with F or f. Examples are: 3.1415926f, 4.0f, 6.022e+23f. It is important to note that floating-point numbers are inexact. Some numbers like 0.1f cannot be represented exactly as codice_6s but will have a small error. Very large and very small numbers will have less precision and arithmetic operations are sometimes not associative or distributive because of a lack of precision. Nonetheless, floating-point numbers are most commonly used for approximating real numbers and operations on them are efficient on modern microprocessors. Floating-point arithmetic is explained in more detail on Wikipedia. codice_6 variables can be declared using the float keyword. A codice_6 is only one machine word in size. Therefore, it is used when less precision than a double provides is required. The codice_7 type. The double and float types are very similar. The float type allows you to store single-precision floating point numbers, while the double keyword allows you to store double-precision floating point numbers – real numbers, in other words. Its size is typically two machine words, or 8 bytes on most machines. Examples of double literals are 3.1415926535897932, 4.0, 6.022e+23 (scientific notation). If you use 4 instead of 4.0, the 4 will be interpreted as an int. The distinction between floats and doubles was made because of the differing sizes of the two types. When C was first used, space was at a minimum and so the judicious use of a float instead of a double saved some memory. Nowadays, with memory more freely available, you rarely need to conserve memory like this – it may be better to use doubles consistently. Indeed, some C implementations use doubles instead of floats when you declare a float variable. If you want to use a double variable, use the double keyword. sizeof. If you have any doubts as to the amount of memory actually used by any variable (and this goes for types we'll discuss later, also), you can use the sizeof operator to find out for sure. (For completeness, it is important to mention that sizeof is a unary operator, not a function.) Its syntax is: sizeof object sizeof(type) The two expressions above return the size of the object and type specified, in bytes. The return type is size_t (defined in the header <stddef.h>) which is an unsigned value. Here's an example usage: size_t size; int i; size = sizeof(i); size will be set to 4, assuming CHAR_BIT is defined as 8, and an integer is 32 bits wide. The value of sizeof's result is the number of bytes. Note that when sizeof is applied to a char, the result is 1; that is: sizeof(char) always returns 1. Data type modifiers. One can alter the data storage of any data type by preceding it with certain modifiers. long and short are modifiers that make it possible for a data type to use either more or less memory. The int keyword need not follow the short and long keywords. This is most commonly the case. A short can be used where the values fall within a lesser range than that of an int, typically -32768 to 32767. A long can be used to contain an extended range of values. It is not guaranteed that a short uses less memory than an int, nor is it guaranteed that a long takes up more memory than an int. It is only guaranteed that sizeof(short) <= sizeof(int) <= sizeof(long). Typically a short is 2 bytes, an int is 4 bytes, and a long either 4 or 8 bytes. Modern C compilers also provide long long which is typically an 8 byte integer. In all of the types described above, one bit is used to indicate the sign (positive or negative) of a value. If you decide that a variable will never hold a negative value, you may use the unsigned modifier to use that one bit for storing other data, effectively doubling the range of values while mandating that those values be positive. The unsigned specifier also may be used without a trailing int, in which case the size defaults to that of an int. There is also a signed modifier which is the opposite, but it is not necessary, except for certain uses of char, and seldom used since all types (except char) are signed by default. The long modifier can also be used with double to create a long double type. This floating-point type may (but is not required to) have greater precision than the double type. To use a modifier, just declare a variable with the data type and relevant modifiers: unsigned short int usi; /* fully qualified -- unsigned short int */ short si; /* short int */ unsigned long uli; /* unsigned long int */ const qualifier. When the const qualifier is used, the declared variable must be initialized at declaration. It is then not allowed to be changed. While the idea of a variable that never changes may not seem useful, there are good reasons to use const. For one thing, many compilers can perform some small optimizations on data when it knows that data will never change. For example, if you need the value of π in your calculations, you can declare a const variable of pi, so a program or another function written by someone else cannot change the value of pi. Note that a Standard conforming compiler must issue a warning if an attempt is made to change a const variable - but after doing so the compiler is free to ignore the const qualifier. Magic numbers. When you write C programs, you may be tempted to write code that will depend on certain numbers. For example, you may be writing a program for a grocery store. This complex program has thousands upon thousands of lines of code. The programmer decides to represent the cost of a can of corn, currently 99 cents, as a literal throughout the code. Now, assume the cost of a can of corn changes to 89 cents. The programmer must now go in and manually change each entry of 99 cents to 89. While this is not that big a problem, considering the "global find-replace" function of many text editors, consider another problem: the cost of a can of green beans is also initially 99 cents. To reliably change the price, you have to look at every occurrence of the number 99. C possesses certain functionality to avoid this. This functionality is approximately equivalent, though one method can be useful in one circumstance, over another. Using the const keyword. The const keyword helps eradicate magic numbers. By declaring a variable const corn at the beginning of a block, a programmer can simply change that const and not have to worry about setting the value elsewhere. There is also another method for avoiding magic numbers. It is much more flexible than const, and also much more problematic in many ways. It also involves the preprocessor, as opposed to the compiler. Behold... #define. When you write programs, you can create what is known as a "macro", so when the computer is reading your code, it will replace all instances of a word with the specified expression. Here's an example. If you write when you want to, for example, print the price of corn, you use the word codice_27 instead of the number 0.99 – the preprocessor will replace all instances of codice_27 with 0.99, which the compiler will interpret as the literal codice_7 0.99. The preprocessor performs substitution, that is, codice_27 is replaced by 0.99 so this means there is no need for a semicolon. It is important to note that codice_31 has basically the same functionality as the "find-and-replace" function in a lot of text editors/word processors. For some purposes, codice_31 can be harmfully used, and it is usually preferable to use codice_33 if codice_31 is unnecessary. It is possible, for instance, to codice_31, say, a macro codice_36 as the number 3, but if you try to print the macro, thinking that codice_36 represents a string that you can show on the screen, the program will have an error. codice_31 also has no regard for type. It disregards the structure of your program, replacing the text "everywhere" (in effect, disregarding scope), which could be advantageous in some circumstances, but can be the source of problematic bugs. You will see further instances of the codice_31 directive later in the text. It is good convention to write codice_31d words in all capitals, so a programmer will know that this is not a variable that you have declared but a codice_31d macro. It is not necessary to end a preprocessor directive such as codice_31 with a semicolon; in fact, some compilers may warn you about unnecessary tokens in your code if you do. Scope. In the Basic Concepts section, the concept of scope was introduced. It is important to revisit the distinction between local types and global types, and how to declare variables of each. To declare a local variable, you place the declaration at the beginning (i.e. before any non-declarative statements) of the block to which the variable is deemed to be local. To declare a global variable, declare the variable outside of any block. If a variable is global, it can be read, and written, from anywhere in your program. Global variables are not considered good programming practice, and should be avoided whenever possible. They inhibit code readability, create naming conflicts, waste memory, and can create difficult-to-trace bugs. Excessive usage of globals is usually a sign of laziness or poor design. However, if there is a situation where local variables may create more obtuse and unreadable code, there's no shame in using globals. Other Modifiers. Included here, for completeness, are more of the modifiers that standard C provides. For the beginning programmer, "static" and "extern" may be useful. "volatile" is more of interest to advanced programmers. "register" and "auto" are largely deprecated and are generally not of interest to either beginning or advanced programmers. static. static is sometimes a useful keyword. It is a common misbelief that the only purpose is to make a variable stay in memory. When you declare a function or global variable as "static", you cannot access the function or variable through the extern (see below) keyword from other files in your project. This is called "static linkage". When you declare a local variable as "static", it is created just like any other variable. However, when the variable goes out of scope (i.e. the block it was local to is finished) the variable stays in memory, retaining its value. The variable stays in memory until the program ends. While this behaviour resembles that of global variables, static variables still obey scope rules and therefore cannot be accessed outside of their scope. This is called "static storage duration". Variables declared static are initialized to zero (or for pointers, NULL) by default. They can be initialized explicitly on declaration to any "constant" value. The initialization is made just once, at compile time. You can use static in (at least) two different ways. Consider this code, and imagine it is in a file called jfile.c: static int j = 0; void up(void) /* k is set to 0 when the program starts. The line is then "ignored" * for the rest of the program (i.e. k is not set to 0 every time up() * is called) static int k = 0; j++; k++; printf("up() called. k= %2d, j= %2d\n", k , j); void down(void) static int k = 0; j--; k--; printf("down() called. k= %2d, j= %2d\n", k , j); int main(void) int i; /* call the up function 3 times, then the down function 2 times */ for (i = 0; i < 3; i++) up(); for (i = 0; i < 2; i++) down(); return 0; The codice_43 variable is accessible by both up and down and retains its value. The codice_44 variables also retain their value, but they are two different variables, one in each of their scopes. Static variables are a good way to implement encapsulation, a term from the object-oriented way of thinking that effectively means not allowing changes to be made to a variable except through function calls. Running the program above will produce the following output: up() called. k= 1, j= 1 up() called. k= 2, j= 2 up() called. k= 3, j= 3 down() called. k= -1, j= 2 down() called. k= -2, j= 1 Features of codice_45 variables : 1. Keyword used - static 2. Storage - Memory 3. Default value - Zero 4. Scope - Local to the block in which it is declared 5. Lifetime - Value persists between different function calls 6. Keyword optionality - Mandatory to use the keyword extern. extern is used when a file needs to access a variable in another file that it may not have #included directly. Therefore, "extern" does not allocate memory for the new variable, it just provides the compiler with sufficient information to access a variable declared in another file. Features of codice_46 variable : 1. Keyword used - extern 2. Storage - Memory 3. Default value - Zero 4. Scope - Global (all over the program) 5. Lifetime - Value persists till the program's execution comes to an end 6. Keyword optionality - Optional if declared outside all the functions volatile. volatile is a special type of modifier which informs the compiler that the value of the variable may be changed by external entities other than the program itself. This is necessary for certain programs compiled with optimizations – if a variable were not defined volatile then the compiler may assume that certain operations involving the variable are safe to optimize away when in fact they aren't. "volatile" is particularly relevant when working with embedded systems (where a program may not have complete control of a variable) and multi-threaded applications. auto. auto is a modifier which specifies an "automatic" variable that is automatically created when in scope and destroyed when out of scope. If you think this sounds like pretty much what you've been doing all along when you declare a variable, you're right: all declared items within a block are implicitly "automatic". For this reason, the "auto" keyword is more like the answer to a trivia question than a useful modifier, and there are lots of very competent programmers that are unaware of its existence. Features of codice_47 variables : 1. Keyword used - auto 2. Storage - Memory 3. Default value - Garbage value (random value) 4. Scope - Local to the block in which it is defined 5. Lifetime - Value persists while the control remains within the block 6. Keyword optionality - Optional register. register is a hint to the compiler to attempt to optimize the storage of the given variable by storing it in a register of the computer's CPU when the program is run. Most optimizing compilers do this anyway, so use of this keyword is often unnecessary. In fact, ANSI C states that a compiler can ignore this keyword if it so desires – and many do. Microsoft Visual C++ is an example of an implementation that completely ignores the "register" keyword. Features of codice_48 variables : 1. Keyword used - register 2. Storage - CPU registers (values can be retrieved faster than from memory) 3. Default value - Garbage value 4. Scope - Local to the block in which it is defined 5. Lifetime - Value persists while the control remains within the block 6. Keyword optionality - Mandatory to use the keyword

Computer Programming/Variables. An assignment statements in wikibook pseudocode is written as codice_1. let X := 10 But this is not needed in wikibook pseudocode.

English in Use. Welcome. Welcome to English in Use, a book about the actual use of the English language. It features sections about types of grammar, punctuation and formality. This wikibook is intended for use by native speakers of English or advanced learners of English as a second/foreign language. If you wish to learn English, then you should use one of the English books for students learning English as a second/foreign language. For new learners of English, try English for beginners book. If you have some experience of English but need to refresh your knowledge, try the English for B2 Students Wikibook. If you're preparing for the Cambridge FCE exam (Cambridge English: First), then head to the module. Those interested in English for business contexts should try the Business English Wikibook.

Computer Programming/Types. Computer Programming Types determine the kinds of values and how they can be used in the given programming environment. In most cases, a programming language defines a set of basic data types, e.g. for numbers, characters or strings. In higher languages, it is often possible to define new data types from the existing ones, for example, to represent a postal address (consisting of strings for street and city and integers for the postal code). When communicating data between different programs and computer systems it is important to either use types that both can recognize, or have a means of translating between them. Type Definition. A complete definition of a data type consists of up to three things: Primitive Types. There are a few basic data types seen in some programming languages:

Data Structures/Arrays. Arrays. An array is a collection, mainly of similar data types, stored into a common variable. The collection forms a data structure where objects are stored linearly, one after another in memory. Sometimes arrays are even replicated into the memory hardware. The structure can also be defined as a particular method of storing elements of indexed data. Elements of data are logically stored sequentially in blocks within the array. Each element is referenced by an index, or subscripts. The index is usually a number used to address an element in the array. For example, if you were storing information about each day in August, you would create an array with an index capable of addressing 31 values—one for each day of the month. Indexing rules are language dependent, however most languages use either 0 or 1 as the first element of an array. The concept of an array can be daunting to the uninitiated, but it is really quite simple. Think of a notebook with pages numbered 1 through 12. Each page may or may not contain information on it. The notebook is an "array" of pages. Each page is an "element" of the array 'notebook'. Programmatically, you would retrieve information from a page by referring to its number or "subscript", i.e., notebook(4) would refer to the contents of page 4 of the array notebook. <br>"The notebook (array) contains 12 pages (elements)" Arrays can also be multidimensional - instead of accessing an element of a one-dimensional list, elements are accessed by two or more indices, as from a matrix or tensor. Multidimensional arrays are as simple as our notebook example above. To envision a multidimensional array, think of a calendar. Each page of the calendar, 1 through 12, is an element, representing a month, which contains approximately 30 elements, which represent days. Each day may or may not have information in it. Programmatically then, calendar(4,15) would refer to the 4th month, 15th day. Thus we have a two-dimensional array. To envision a three-dimensional array, break each day up into 24 hours. Now calendar(4,15,9) would refer to 4th month, 15th day, 9th hour. <br>"A simple 6 element by 4 element array" Arrays guarantee constant time read and write access, formula_1, however many lookup operations (find_min, find_max, find_index) of an instance of an element are linear time, formula_2. Arrays are very efficient in most languages, as operations compute the address of an element via a simple formula based on the base address element of the array. Array implementations differ greatly between languages: some languages allow arrays to be re-sized automatically, or to even contain elements of differing types (such as Perl). Other languages are very strict and require the type and length information of an array to be known at run time (such as C). Arrays typically map directly to contiguous storage locations within your computer's memory and are therefore the "natural" storage structure for most higher level languages. Simple linear arrays are the basis for most of the other data structures. Many languages do not allow you to allocate any structure except an array, everything else must be implemented on top of the array. The exception is the linked list, that is typically implemented as individually allocated objects, but it is possible to implement a linked list within an array. Type. The array index needs to be of some type. Usually, the standard integer type of that language is used, but there are also languages such as Ada and Pascal which allow any discrete type as an array index. Scripting languages often allow any type as an index (associative array). Bounds. The array index consists of a range of values with a lower bound and an upper bound. In some programming languages only the upper bound can be chosen while the lower bound is fixed to be either 0 or 1 . In other programming languages both the upper and lower bound can be freely chosen . Bounds check. The third aspect of an array index is the check for valid ranges and what happens when an invalid index is accessed. This is a very important point since the majority of computer worms and computer viruses attack by using invalid array bounds. There are three options open: Declaring Array Types. The declaration of array type depends on how many features the array in a particular language has. The easiest declaration is when the language has a fixed lower bound and fixed index type. If you need an array to store the monthly income you could declare in C typedef double Income[12]; This gives you an array with in the range of 0 to 11. For a full description of arrays in C see C Programming/Arrays. If you use a language where you can choose both the lower bound as well as the index type, the declaration is—of course—more complex. Here are two examples in Ada: type Month is range 1 .. 12; type Income is array(Month) of Float; or shorter: type Income is array(1 .. 12) of Float; For a full description of arrays in Ada see Ada Programming/Types/array. Array Access. We generally write arrays with a name, followed by the index in some brackets, square '[]' or round '()'. For example, August[3] is the method used in the C programming language to refer to a particular day in the month. Because the C language starts the index at zero, August[3] is the 4th element in the array. august[0] actually refers to the first element of this array. Starting an index at zero is natural for computers, whose internal representations of numbers begin with zero, but for humans, this unnatural numbering system can lead to problems when accessing data in an array. When fetching an element in a language with zero-based indexes, keep in mind the "true" length of an array, lest you find yourself fetching the wrong data. This is the disadvantage of programming in languages with fixed lower bounds, the programmer must always remember that "[0]" means "1st" and, when appropriate, add or subtract one from the index. Languages with variable lower bounds will take that burden off the programmer's shoulder. We use indexes to store "related" data. If our C language array is called august, and we wish to store that we're going to the supermarket on the 1st, we can say, for example august[0] = "Going to the shops today" In this way, we can go through the indexes from 0 to 30 and get the related tasks for each day in august.

Spanish/Lesson 7. Grammar - Preterite (el pretérito indefinido). The following table shows the preterite of regular verbs. Regular -er and -ir verbs follow the exact same pattern. Note that the nosotros form is the same as in the present tense for -ar and -ir verbs, so you have to know the context to figure out the time. Also, note that the last letter of comí and viví has an accent mark. Here is a list of common verbs that have an irregular preterite: Exercise: Preterite Grammar - Imperfect (el pretérito imperfecto). The following table shows the imperfect of regular verbs. Note that regular -er and -ir verbs follow the exact same pattern: There are only three verbs that are irregular in the imperfect: Grammar - Preterite vs. Imperfect. Spanish has two tenses that correspond to the English "simple past". Roughly speaking, the Preterite is used to tell What happened - it refers to a specific event. The Imperfect is used to tell How things were - it refers to the general situation. Exercise: Preterite vs. Imperfect

C Programming/Arrays and strings. Arrays in C act to store related data under a single variable name with an index, also known as a "subscript". It is easiest to think of an array as simply a list or ordered grouping for variables of the same type. As such, arrays often help a programmer organize collections of data efficiently and intuitively. Later we will consider the concept of a "pointer", fundamental to C, which extends the nature of the array (array can be termed as a constant pointer). For now, we will consider just their declaration and their use. Arrays. C arrays are declared in the following form: type name[number of elements]; For example, if we want an array of six integers (or whole numbers), we write in C: int numbers[6]; For a six character array called "letters", char letters[6]; and so on. You can also initialize as you declare. Just put the initial elements in curly brackets separated by commas as the initial value: For example, if we want to initialize an array with six integers, with 0, 0, 1, 0, 0, 0 as the initial values: int point[6]={0,0,1,0,0,0}; Though when the array is initialized as in this case, the array dimension may be omitted, and the array will be automatically sized to hold the initial data: int point[]={0,0,1,0,0,0}; This is very useful in that the size of the array can be controlled by simply adding or removing initializer elements from the definition without the need to adjust the dimension. If the dimension is specified, but not all elements in the array are initialized, the remaining elements will contain a value of 0. This is very useful, especially when we have very large arrays. int numbers[2000]={245}; The above example sets the first value of the array to 245, and the rest to 0. If we want to access a variable stored in an array, for example with the above declaration, the following code will store a 1 in the variable x int x; x = point[2]; Arrays in C are indexed starting at 0, as opposed to starting at 1. The first element of the array above is point[0]. The index to the last value in the array is the array size minus one. In the example above the subscripts run from 0 through 5. C does not guarantee bounds checking on array accesses. The compiler may not complain about the following (though the best compilers do): char y; int z = 9; char point[6] = { 1, 2, 3, 4, 5, 6 }; //examples of accessing outside the array. A compile error is not always raised y = point[15]; y = point[-4]; y = point[z]; During program execution, an out of bounds array access does not always cause a run time error. Your program may happily continue after retrieving a value from point[-1]. To alleviate indexing problems, the sizeof() expression is commonly used when coding loops that process arrays. Many people use a macro that in turn uses sizeof() to find the number of elements in an array, a macro variously named "lengthof()", "MY_ARRAY_SIZE()" or "NUM_ELEM()", "SIZEOF_STATIC_ARRAY()", etc. int ix; short anArray[]= { 3, 6, 9, 12, 15 }; for (ix=0; ix< (sizeof(anArray)/sizeof(short)); ++ix) { DoSomethingWith("%d", anArray[ix] ); Notice in the above example, the size of the array was not explicitly specified. The compiler knows to size it at 5 because of the five values in the initializer list. Adding an additional value to the list will cause it to be sized to six, and because of the sizeof expression in the for loop, the code automatically adjusts to this change. Good programming practice is to declare a variable size , and store the number of elements in the array in it. size = sizeof(anArray)/sizeof(short) C also supports multi dimensional arrays (or, rather, arrays of arrays). The simplest type is a two dimensional array. This creates a rectangular array - each row has the same number of columns. To get a char array with 3 rows and 5 columns we write in C char two_d[3][5]; To access/modify a value in this array we need two subscripts: char ch; ch = two_d[2][4]; or two_d[0][0] = 'x'; Similarly, a multi-dimensional array can be initialized like this: int two_d[2][3] = ; The number of columns must be explicitly stated; however, the compiler will find the appropriate amount of rows based on the initializer list. There are also weird notations possible: int a[100]; int i = 0; if (a[i]==i[a]) printf("Hello world!\n"); a[i] and i[a] refer to the same location. (This is explained later in the next Chapter.) Strings. C has no string handling facilities built in; consequently, strings are defined as arrays of characters. C allows a character array to be represented by a character string rather than a list of characters, with the null terminating character automatically added to the end. For example, to store the string "Merkkijono", we would write char string[11] = "Merkkijono"; or char string[11] = {'M', 'e', 'r', 'k', 'k', 'i', 'j', 'o', 'n', 'o', '\0'}; In the first example, the string will have a null character automatically appended to the end by the compiler; by convention, library functions expect strings to be terminated by a null character. The latter declaration indicates individual elements, and as such the null terminator needs to be added manually. Strings do not always have to be linked to an explicit variable. As you have seen already, a string of characters can be created directly as an unnamed string that is used directly (as with the printf functions.) To create an extra long string, you will have to split the string into multiple sections, by closing the first section with a quote, and recommencing the string on the next line (also starting and ending in a quote): char string[58] = "This is a very, very long " "string that requires two lines."; While strings may also span multiple lines by putting the backslash character at the end of the line, this method is deprecated. There is a useful library of string handling routines which you can use by including another header file. This standard string library will allow various tasks to be performed on strings, and is discussed in the Strings chapter.

Calculus. Welcome to the Wikibook of Calculus This wikibook aims to be a high quality calculus textbook through which users can master the discipline. Standard topics such as "limits", "differentiation" and "integration" are covered, as well as several others. Please contribute wherever you feel the need. You can simply help by rating individual sections of the book that you feel were inappropriately rated!

Japanese/Kanji. Kanji () characters are based on Chinese characters transmitted to Japan during the spread of Buddhism in the 5th century. A large percentage (approx. 70%) of Japanese vocabulary comes from Chinese or Chinese-derived words. While the meaning of individual characters is fairly consistent between the languages, compound words often have different meanings. Kanji are inflected by hiragana that follow and particles give the case. Most words are written using kanji, though some have none and loan-words from other languages are generally written in katakana. The large number of homophones makes it highly desirable to use kanji and knowing them can help with memorising new words. Note that "writing" kanji skillfully is significantly harder than "reading" kanji skillfully, since one must "recall" characters, not simply "recognize" them. Further, with Input Methods allowing one to write Japanese on a computer phonetically (by recognizing the kanji, not needing to produce them), the practical need for kanji writing skills is lower than in the past, but it is still fundamental to mastery of Japanese. Study methods. Kanji can form a difficult hurdle for some in their study of Japanese. Their nature as graphic representations of concepts translating to sounds gives rise to the particularly diverse methods employed for the study of kanji. Fundamentally, one’s goal is to learn "Japanese," not "kanji" per se and this has two main implications. Firstly, as many words are written as compounds of multiple kanji it is not sufficient learn the individual two thousand odd characters, but also their combinations. Furthermore, just as learning vocabulary in any language, these must be learnt in the context of the language. Not only does it aid memorisation of terms, but enforces the understanding of their nuance. It is finally worth mentioning that one can learn to speak Japanese without learning to read or write it, just as with any language. If one is, however, ever to learn to read, it is advisable to start right away and learn the characters in parallel with vocabulary and phrases. Throughout, understand that one’s mastery of any skill is imperfect, impermanent, and incomplete (see 侘寂, "wabi-sabi") – while perfection is a worthy goal, it should not be expected nor demanded – mistakes should be expected, and accept that there are further levels of mastery: not 300 people a year pass the Kanji kentei level 1. Basic issues, regardless of study methods: Because there are so many kanji, and they are relatively sparse (of 1,945 kanji, most will not be used and reinforced in any sample of text, unlike kana) simply memorizing the forms and pronunciations (as one does for the 26 letters of the Latin alphabet or the 46 kana, twice) is less practical and effective, and one instead uses more structured mnemonic methods. There are three aspects to a particular kanji: There are a number of ways to learn the kanji. Rather than pick one, try to see how each of these works for you and combine them in your study. Rote. The most straightforward way of learning kanji is by rote. While few will succeed in retaining even a portion of the two thousand basic characters — not to mention their compounds — rote learning is a good way to practice mnemonic devices such as those mentioned in the following sections. Writing reinforces character details, builds muscle memory and improves handwriting. Thus, regardless of learning system, practicing "writing" the kanji is a valuable aspect of learning. Make flash-cards with one or more characters on one side, the meaning and reading on the other and drill yourself. Make another set of cards with the meaning on one side and the characters and readings on the other and drill yourself on writing the kanji. There are several programs and website applications that offer kanji drilling. Notable spaced recognition software include Anki and Mnemosyne. Forgetting a rarely used kanji is easy so it is important to regularly review these. Handwriting. Note that characters have a generally accepted stroke order. While this may seem an extra burden at first, the order is highly regular and will vastly improve your ability to read other people's handwriting, not to mention make yours more intelligible. As with the handwriting of most scripts, Japanese calligraphy has a long history and is greatly revered to this day. As kanji are somewhat more intricate than Latin characters, the quality of handwriting and the order the strokes are written in matter a great deal. In fact, without a commonly accepted system, cursive styles and hurried handwriting would be illegible, indeed. There is, of course, only one way to practice handwriting: By writing. Get yourself a nice notebook, preferable one with good sized squares, and practice, practice, practice. Context. The "Kanji in Context" texts from the Inter-University Center for Japanese Language Studies emphasizes the value of learning not so much kanji characters in isolation, but "kanji-based vocabulary," particularly as part of phrases or idioms. In this approach, when learning a kanji, one learns important words that it is part of. Further, one will learn kanji that make up a given word at the same time – for example, one will learn the "word" 日本 (Nihon, Japan) and, at the same time, the characters 日 (nichi, ni, sun) and 本 (hon, root). Recognising the constituent parts. As you progress in learning kanji, you'll start to see patterns emerge; constituent parts of characters that are common among many characters. Recognising these will allow you to see the characters as made up of shapes rather than just strokes and thus simplify retaining them. The general method is to systematically break up characters into graphical components, some of which may not be used as separate characters. Next, one systematically maps these elements to some mnemonic, and then builds a picture or story combining these. The principles at work are: Useful resources for diagnosing these constituent parts are the book and online version of "Kanji ABC". James Heisig's well-known series "Remembering the Kanji" is the best known study aid that uses this method. Alternatives include Smart Kanji Book which only includes common kanji and the primitives that form them and the Kanji Pict-o-graphix which uses a graphic approach instead of mnemonic stories. A further such resource is Genki’s Kanji Look and Learn. These may not be sufficient in themselves, as they focus purely on the characters, but can be valuable components of one’s learning, helping with remembering character forms and especially minor details. Chinese-derived reading. The vast majority of Chinese characters are composed as "phono-semantic compounds": one component (generally the radical) is semantic (about the meaning), and the other component is used for its phonetic value (sound) called . Note that this is how the character as used in "Chinese" is composed. As kanji usually have several readings, including a Chinese-derived one, this can be used to remember the character and one of its readings. Understanding this, and decomposing characters into Phonetic + Semantic components and relating them to similar characters using either of these components helps with remembering the character’s form, its meaning, and a Chinese-derived pronunciation ("on yomi," 音読み). For example, the character for small is 小 which has the Chinese-derived reading shō. The characters 少, 炒, 抄, 省, 称, 鈔 and 渉 all share that same Chinese reading. Again, keep in mind that these are only the "Chinese" readings and the each of these has other different readings as well. Attention to detail. It is easy to make minor mistakes with both recognizing and writing kanji. A high level of mastery requires attention to detail and continual polish (see 改善, "kaizen"). Even at lower levels, attention to detail yields overlearning and deepens understanding; if you are worrying about the stroke order, you are likely not forgetting the character outright. Minor errors can be made in writing (e.g. incorrect strokes, strokes touching when they should not, or incorrect stroke order) and pronunciation (e.g. incorrect voicing; especially "rendaku"/"euphonic changes"). To achieve a high level requires "detecting" and "correcting" such errors. Realizing that one has forgotten a kanji is easy enough. For other errors, one may not notice them, or one may feel a "lack of confidence" reflecting imperfect mastery. To detect such errors one must review regularly and ensure that all these details are correct. Particularly useful in subtle errors is to study the character in question with various related characters (both graphically, as in , and etymologically), and in the context of various words: this allows one to "contrast" the character, rather than trying to retain it in isolation. Readings. A single Kanji letter can be read (pronounced) in many different ways, depending on its context. These readings are categorized into two main groups - that of Chinese origin (on-yomi, ) and Japanese origin (kun-yomi, ). A third group, the nanoriyomi, is used for the names of people and places. It is often the case that a Kanji letter has more than one reading of Chinese origin. This is because the importing of Chinese letters (with their readings) did not occur just at one time from one region. Onyomi. Onyomi (音読み) is the Chinese-derived reading, which is most commonly used in compound words and for the numbers. It may be useful to note that in most kanji databases, the "on" reading is written in katakana instead of hiragana. 一 (イチ), 二 (ニ), 三 (サン), 四 (シ) are the first four numbers and all are onyomi. Kunyomi. Kunyomi (訓読み) is the Japanese reading, which can be read as a separate word or can be used in compounds. This reading is generally written in hiragana in kanji lists. 月 (つき, tsuki) and 日 (ひ, hi) are the moon and sun and are in kunyomi. Nanoriyomi. Nanoriyomi (名乗り読み) is the name reading, which is used for people's names and for places. Both "康", read as "やす" (e.g. 徳川家康), and "信", read as "のぶ" (e.g. 織田信長), are written in nanoriyomi. Kanji Repetition. The noma: (々), symbol indicates the repetition of a Kanji. The word われわれ indicates "us" or "our group" and is written as "我々" instead of "我我", although they are both the same. The same is true with "人々" (ひとびと), meaning people). JLPT. The Japanese Language Proficiency Test (), or JLPT, is a standardized test to evaluate and certify the language proficiency of non-native Japanese speakers. The JLPT has five levels beginning at level N5 and progressing to level N1 - the most difficult. Each level has a certain set of kanji. JLPT level N5. N5 tests students' recognition of 79 kanji and 482 words. JLPT level N4. N4 tests students' recognition of 166 kanji and 453 words. JLPT level N3. N3 tests students' recognition of 367 kanji and 1555 words. JLPT level N2. N2 tests students' recognition of 367 kanji and 1481 words. JLPT level N1. N1 tests students' recognition of 1231 kanji and 2773 words.

Spanish/Verbs. Otras temas de los verbos. Verbos con la voz pasiva. An action takes place without anyone being assigned responsibility for doing it. Verbos reflexivos. Reflexive verbs indicate that the action of the verb reflects back on the subject. External Links. Spanish Wikibook | ../Verb Tenses/ | ../Verbs List/

Spanish/Contributors. The Spanish Wikibook was created on August 2, 2003 by ; it was the first language book on Wikibooks. During December 2006, it underwent a complete archive and rewrite, by . A list of major contributors — past and present — can be found below.

Spanish/Lesson 8. Grammar - Formal Commands (el imperativo). Commands are used when you ask someone to do something or give instructions to people. In this lesson we learn the formal commands, which are the ones you say to persons where you use the usted or ustedes form. The following table shows the endings for the regular verbs. Note that the stem changes that occur in the yo form, (e->ie, e->i, o->ue, ar/er/ir->go cer->zco etc., ) apply for formal commands: The following verbs have irregular formal commands: Like in English, the command is usually put in the beginning of the sentence: Examples: Grammar - Informal Tú-Commands. In this lesson we learn the commands you say to someone you would address in the tú form. Spanish distinguishes two different types of tú-commands, the affirmative ("do something") and the negative ("don't do something"). Like the formal commands, we also apply stem changes here: The following verbs have irregular informal tú-commands for the affirmative and negative. <br> This can be memorized with the rhyming mnemonic device "di haz pon ten, sal sé ve ven." Examples:

Spanish/Infinitive. The infinitive is the simple, unconjugated form of a verb. It does not indicate who is doing the action or any time reference. "To be" is a verb in the English infinitive form. "Ser" is a verb in the Spanish infinitive form. When you look up a verb in the dictionary it is found in the infinitive form. In Spanish the infinitive forms always end with "ar", "er" or "ir". Examples: "amar" (to love), "temer" (to fear), "partir" (to leave). The infinitive can be used for a lot of things in Spanish grammar. It functions as a gerund in Spanish. In the following examples, I will use "nadar" (to swim):

Organic Chemistry/Introduction to reactions/Redox reactions. Oxidation and reduction. Two important types of reactions in organic chemistry are oxidation and reduction. In oxidation reactions, the oxidized species "loses electron density." In reduction reactions, the reduced species "gains electron density." Of course, these two actions happen in unison as one species is reduced and the other is oxidized. The term redox was coined from the fragments "red" (reduction) and "ox" (oxidation). A standard mnemonic for the terms is “OILRIG”: oxidation is loss, reduction is gain. Oxidation. Oxidation was first observed when oxygen drew electrons off of metals, which were then referred to as "oxidized". (Oxygen is more elecronegative than most other elements.) The term was then applied later to the part of any reaction where electrons are drawn off. Other elements that commonly oxidize in organic reactions include halogens like chlorine and bromine. Reduction. Reduction of a chemical species results in the gain of electrons for that species. This does not necessarily include any change in formal charge; any time an atom increases its electron density even a little bit it is said to be reduced. For example, if an oxygen is removed from a carbon and replaced by a hydrogen (assume the oxygen is also bonded to another atom), the formal charge of the carbon does not change. However, the carbon "sees" a greater share of the electrons from the single bond to hydrogen than it did for the single bond to oxygen. That is because hydrogen is less electronegative than oxygen and gives up its electrons a bit more easily than oxygen does. So a carbon bonded to hydrogen can take up more of its electron density than the same carbon bonded to oxygen. Oxidation numbers. It's possible to assign an “oxidation number” to each atom in a molecule. There are a two different approaches to this. For organic molecules it is generally possible to find all the oxidation numbers using a set of simplified rules. There is no single best set of rules, but as an example, given in order of decreasing priority: From this it is possible to find, for example, that the oxidation state of carbon in methanal: We find that: Denoting the oxidation number of carbon as , we have Carbon has oxidation number zero. Verify for yourself that in methane it has −4, and in ethane −3. An alternative and more general approach is to take the structure of the molecule, and break the bonds such that: As usual, a single bond holds two electrons and a double bond four. (There are further complications which we will not go into here.) The charge of each atom after this process is its oxidation number. Given that oxygen is more electronegative than carbon, which is more electronegative than hydrogen, verify that this gives the same results as before for methanal, methane, and ethane. Both methods give the result that in a neutral species containing only a single element (such as H2 or graphene) all atoms have oxidation state 0.

Organic Chemistry/Introduction to reactions/Functional groups in reactions. Functional groups in reactions make your life easier as an organic chemist because they draw your attention right to where the action is. Any time a reaction is going to occur, you can be almost certain that it is going to take place at a functional group. There are many functional groups of interest to organic chemists. Here are a few: 1. Halides These groups are all made up of a single atom in Group 17 of the Periodic Table, which is known as the halogen group, bonded to a carbon atom. They include fluorine, chlorine, bromine, and iodine. Astatine is also a halogen, but it is rarely discussed because it is not readily found in nature and is radioactive. Their electronegativities vary from fluorine with 4.0 to iodine with 2.5, which is approximately the same value that carbon has. Each of these atoms are able to form a single bond with a carbon atom, replacing hydrogen in alkanes and adding across multiple bonds in alkenes and alkyne. Of the four, fluorine is the most reactive and iodine is the least. Because of their intermediate reactivity, chlorine and bromine are often more useful in many reactions. 2. Carbonyl This group consists of an oxygen atom doubly bonded to a carbon atom. Carbonyl groups are important because the oxygen atom, with an electronegativity of 3.5, shifts electron density away from the rest of the molecule and towards itself. Carbonyls are a key ingredient in aldehydes, ketones, carboxylic acids, esters, and amides. 3. Hydroxyl This group consists of a hydrogen atom singly bonded to an oxygen atom. The electronegativity difference between hydrogen, which has an electronegatity of 2.1, and oxygen, 3.5, pulls electrons away from the hydrogen and makes it somewhat acidic. This acidic character varies depending on the composition of the rest of the molecule. Hydroxyl groups are found in alcohols, phenols, enols, and carboxylic acids.

Organic Chemistry/Introduction to reactions/Drawing reactions. Drawing reactions. There are various techniques you will run across for notation of organic reactions. Arrows. Curved arrows are used to show movement of electrons. They are not used to show where atoms, ions, or molecules move, just electrons. A curved arrow with two "hooks" on the end indicated movement of a pair of electrons. A curved arrow with one "hook" indicated movement of one electron. Double-headed arrows are used to represent equivalence between resonance structures. Two-way double half arrows are represent a reaction that can go forward or reverse. If one of the half arrows is longer than the other it means that the reaction pathway favors that direction with the longer arrow.

General Chemistry/Chemical Reactions. <includeonly> Chemical Reactions. </includeonly>

CACS/Preface. The Wikibook Introduction to computers and communications technology. Scope and Audience. This textbook is intended to provide a comprehensive overview of the field, useful to those who will practice in it, and those who need to deal with it peripherally. While it is not a technical work it does deal with technology and describes its structure, background, content, and business in some detail. This means that it while it can be a general survey, it cannot be necessarily simple. Every attempt is made to add no more complex details than are necessary to place a part of the field in context. But context here also means having a general understanding of the internals of an area, and so some complexity is unavoidable. Thus there are three goals established: These goals may at first seem contradictions, but they are not mutually exclusive. Instead they serve as boundaries to identify the material included for each topic. Another limit is imposed with respect to large or "mainframe" computers. The mainframe environment and history are briefly discussed in the introducyion to each part, but most material is based on the now ubiquitous personal or desktop computer environment. Professional Readers. Those who actively work in computers and communications tend to increase the depth of their knowledge and skills within a limited domain. As they accumulate greater experience and skill, their viewpoint tends to become increasingly that of a single role or area within the discipline. While this text can serve them for an initial survey of the field, its greatest value will be as a continued reference and context to provide a higher level view of those areas outside of their specialty. An online, collaborative text may be particularly valuable in this second role. All of the areas, disciplines, roles, and uses of this technology are changing. Indeed, the rate of change seems to increase geometrically, while the number of areas or specialties increases exponentially. Unlike a paper text, an online one can be maintained rapidly and constantly. Once the reader is familiar with the format and content of the work, future reference is easier. So when presented with a new feature, function, or technology there is an updated textbook that's just like the one they used before. While some may prefer a paper copy for initial use, an updated copy may be continually available. Non-Professional Readers. Very few professions today escape being affected by the application of computers and the related communication technology. For those who work in other disciplines an up to date survey and reference may also be valuable when they must deal with the impact of the technology within their own field. When forced to interact with the high priests of technology, they need not compete to get their viewpoint recognized while ignorant of the goals, practices, and terminology of the ordained. When a piece of these technologies interacts with your own business, this will not replace a user manual, or even the level of the "Topic X for Dummies". What it does is to provide the background and context that make those materials more useful. Terminology. There are four words used in this work that require some explanation. The words "platform, entity, element," and "component" are used loosely, but with some intent. Generally the term entity is used to describe the thing being considered or addressed by a topic, element is used to describe a feature or function of the entity being discussed, and component is used to describe a unit that is considered as a whole, and stands alone for some functions, while platform refers to the group of components that are prerequisite to the entity under discussion. Each term frequently represents the specific being discussed and its peers or similar units that operate at the same level. A specific area or topic may be treated at all four levels. Consider a single Web Page as an example. When describing the Client–Server model of the Internet, it is a "component". When considering HTML it is a part of the "platform". In a part of the discussion of Web Site Construction it is first an "element" of the site, and then an "entity" since there are several topics that directly discuss Web Pages. Structure. The question of how to organize a comprehensive technology overview is both fundamental and complex. You can probably think of ways to improve the organization chosen (I know I do every time I look at it). This section outlines of the survey's major organization into parts and briefly identifies the main subject for each part. The overview is organized into a decomposition hierarchy. The hierarchy is presented two layers at a time. Subject definitions are always presented twice, once with their parent subject and again in their own introduction. "For full detail, see the:" Subject areas and major parts are listed below: Some things fell off this hierarchy, and are contained in other areas of topics. These are: Authors. Any work with the broad and inclusive scope proposed cannot succeed without the contributions of many individuals, both experts and generalists. If this text is to be useful to the general audience, it also needs a lot of amateurs to insure that it stays readable. Thanks in advance to all contributors. As in any good Wiki, details of contribution will be kept for each subject on the page history. Major contributors who wish to be identified will be acknowledged on the CACS/Authors page. There is to be a separate page about writing sections of this book, and it is kept on the CACS/Author Guidelines page. To comment on direction or structure please use the Talk page of the part, chapter, section or topic.

CACS/Authors. This Wikibook is a the result of a collaborative effort by a number or contributors. All of them are gratefully acknowledged, and thanked for their good work. The only ones identified here are those who have chosen to share the blame for its shortcomings. You can contact any of them through their Wikibook user talk page or by eMail. Contributors in alphabetic order are:

CACS. Table of Contents. Appendices. __NOEDITSECTION__

CACS/Glossary. Glossary of Computer and Communications Terms For each term in the Glossary, there is a single data page. When a term is usually known by its acronym, it is defined on a page with that title. When needed, redirect pages will be used to get to that data page from any other frequently used names. Many terms contained here have more information than is displayed in a simple definition. When a word or phrase within a definition is shown in "italics", that word or phrase is also expected to appear in the glossary. A list of All terms is contained at the bottom of this page. Terms in the Glossary include: processes, languages, terms of art, acronyms, hardware devices, software package names, companies and organizations. Every effort is made to note those that are trademarks or proprietary names. All such use is intended to be made under "fair use" conditions and should not reduce the owner's rights or the terms of the GNU/GFDL license applied to this work as a whole. The full text of the free use license that applies here is located at Wikipedia License. "The following is Subject to Change. Currently each term is being set up on a subpage of the Glossary. This is mandated by their intended use in pop-up windows when reading the book." List of Terms. A. - - - - - - - B. - C. - /CSS/ G. - U. - - -

CACS/Glossary/HTML. Hypertext Markup Language (HTML) A document publishing language that mixes content, formatting rules, and processing "scripts" to create "Web Pages". The HTML source is interpreted and displayed by a "browser" on the end user's computer. HTML is an open specification maintained through a consortium of major vendors and corporations known as the "W3C". The most recent, full version of the "language specification" is HTML 4.01 and dates from December 1999. It can be downloaded from the W3C Web Site. HTML (or .htm) is also used as a file extension for a stored web page that uses the language.

Discrete Mathematics/Naive set theory. When we talk of set theory, we generally talk about "collections" of certain mathematical objects. In this sense, a "set" can be likened to a bag, holding a finite (or conceivably infinite) amount of things. Sets can be sets of sets as well (bags with bags in them). However, a set cannot contain duplicates -- a set can contain only one copy of a particular item. When we look at sets of certain types of numbers, for example, the natural numbers, or the rational numbers, for instance, we may want to speak only of these sets. These collections of numbers are, of course, very important, so we write special symbols to signify them. We write sets in curly brackets -- { and }. We write all of the "elements", or what the set contains, in the brackets, separated by commas. We generally denote sets using capital letters. For example, we write the set containing the number 0 and the number 1 as {0,1}. If we wish to give it a name, we can say B={0,1}. Special sets. The aforementioned collections of numbers, the naturals, rationals, etc. are notated as the following: Here we will generally write these in standard face bold instead of the doublestruck bold you see above. So we write here N instead of formula_1 (NB following Wikipedia conventions). Notations. We can write some special relations involving sets using some symbols. Containment relations. To say that an element is in a set, for example, 3 is in the set {1,2,3}, we write: We can also express this relationship in another way: we say that 3 is a "member" of the set {1,2,3}. Also, we can say the set {1,2,3} "contains" 3, but this usage is not recommended as it is also used to refer to subsets (see following). We can say that two sets are equal if they contain exactly the same elements. For example, the sets {2,3,1} and {3,1,2} both contain the numbers 1, 2 and 3. We write: We write the set with "no" elements as formula_11, or {}. Here, we use the notation {} for the "empty set" (NB following Wikipedia conventions). The concept of the subset. A very important concept in set theory and other mathematical areas is the concept of the subset. Say we have two sets A={0,1,2,3,4,5,6,7,8,9}, and B={0,1,2,3,4,5}. Now, B "contains some elements" of A, but not all. We express this relationship between the sets A and B by saying B is a "subset" of A. We write this If B is a subset of A, but A is not a subset of B, B is said to be a "proper subset" of A. We write this Note that if formula_13, then formula_12 Intersections and unions. There are two notable and fundamental special operations on sets, the "intersection" and the "union". These are somewhat analogous to multiplication and addition. Intersection. The intersection of two sets A and B are the elements "common" to both sets. For example, if A={1,3,5,7,9} and B={0,1,3}, their intersection, written formula_16 is the set {1,3}. If the intersection of any two sets are empty, we say these sets are "disjoint". Unions. The union of two sets A and B are the "all" elements in "both" sets. For example if A={1,3,5,7,9} and B={0,2,4,6,8}. We say the union, written formula_17 is the set {0,1,2,3,4,5,6,7,8,9}. Set comprehensions. When we write a set, we can do so by writing all the elements in that set as above. However if we wish to write an "infinite" set, then writing out the elements can be too unwieldy. We can solve this problem by writing sets in "set comprehension" notation. We do this by writing these sets including a "rule" and by a relationship to an "index set", say I. That is; where rule can be something like "x"2, or "x"=3"x". For example, this set forms the set of all even numbers: This set forms the set of all solutions to the general quadratic: Universal sets and complements. Universal sets. When we do work with sets, it is useful to think of a larger set in which to work with. For example, if we are talking about sets {-1,0,1} and {-3,-1,1,3}, we may want to work in Z in this circumstance. When we talk about working in such a larger set, such as Z in that instance, we say that Z is a "universal set", and we take all sets to be subsets of this universal set. We write the universal set to be formula_21, however it may be simpler to denote this as E. Complements. Given a set A in a larger universal set E, we define the complement of A to be all elements in E that are not in A, that is the complement of A is: We write the complement as A' or Ac. In this document we will use A'. Problem set. Based on the above information, write the answers to the following questions Answers. 2. No, the square root of 2 is "irrational", not a rational number<br> 4.1. Yes <br> 4.2. No<br> 6. Yes.<br> 8. 5 elements could be {3,5,7,9,11}.<br> 10. formula_37<br> Further ideas. These mentioned concepts are not the only ones we can give to set theory. Key ideas that are not necessarily given much detail in this elementary course in set theory but later in abstract algebra and other fields, so it is important to take a grasp on these ideas now. These may be skipped. Power set. The "power set", denoted P(S), is the set of "all" subsets of S. NB: The empty set is a subset of all sets. For example, P({0,1})= Cardinality. The "cardinality" of a set, denoted |S| is the amount of elements a set has. So |{a,b,c,d}|=4, and so on. The cardinality of a set need not be finite: some sets have infinite cardinality. The cardinality of the power set. If P(S)=T, then |T|=2|S|. Problem set. Based on the above information, write the answers to the following questions. (Answers follow to even numbered questions) Answers. 2. 23=8<br> 4. Set identities. When we spoke of the two fundamental operators on sets before, that of the "union" and the "intersection", we have a set of rules which we can use to simplify expressions involving sets. For example, given: how can we simplify this? Several of the following set identities are similar to those in standard mathematics This is incomplete and a draft, additional information is to be added

CACS/Index. "This page is not yet a normal Index." "The capabilities of search engines now satisfy some of the needs formerly addressed by a paper index." "That means that as this volume nears completion, the content or use of this page may need redesign." "Currently the page is more of a notepad or guide for an author than it is an aid to the ultimate reader." "For any index entry, there is simply a list of those pages, by full name, that have some bearing on the subject." "Having this cross reference will aid in updating topics that involve several pages as well as reviewing them to ensure consistency." "Please Direct comments and suggestions for the format and content of this page to its Talk Page."

Polish. The Polish language is a member of the Western Slavic group of the Indo-European family of languages. It is easiest to learn if one already knows some other related language. The most closely related are other Western Slavic languages: Czech, Slovak, Silesian, Kashubian and Sorbian. More distant are the Southern and Eastern Slavic languages like Bulgarian, Macedonian, Serbo-Croatian, Slovenian and Russian, Ukrainian, Belorusian, respectively. Polish is spoken by a total of approximately 40 million people, making it the second most widely spoken Slavic language in the world, after Russian. Speakers of related languages can pick it up without much effort. Someone who doesn't speak any Slavic language, but speaks some other Indo-European language, may still find many similarities between Polish grammar and the grammar of that language, as well as many similar words. This Wikibook is designed for anyone who wants to learn the basics of the Polish language. It is suitable for beginners and those who have been learning the language for a few years. Copyright. This document was originally copyright 2002 Tomasz Węgrzanowski & Anna (grammar) <[email protected]> It may be distributed under terms of GNU Free Documentation License. Since its original writing, it has been edited and redistributed on Wiktionary and, currently, Wikibooks. Further reading. __NOEDITSECTION__

General Biology/Gallery of Biologists/Charles Darwin. Charles Darwin (1809 - 1882), British naturalist, founder of the Theory of Evolution by means of natural selection. "Note: Darwin's books should be read with a historical mindset, as they do not always reflect current scientific opinion (though impressively, they often do). Scientifically speaking, the knowledge held in his books should be supplemented with other books in ." Links. Texts Online:

CACS/Glossary/ACWP. Actual Cost of Work Performed (ACWP) The total direct and indirect costs of accomplishing work completed to date. It usually refers either to a given time period or to a completed project phase, activity, or task. Some management techniques compare it to a budget to determine a "variance" or status. In other cases, when it is usually called "earned value", ACWP may be used to determine interim payments to a contractor.

CACS/Glossary/GRE. General Routing Encapsulation (GRE) A method or technique of adding an IP standard header and trailer to a message that does not follow "IP protocols". The encapsulated message is sent over a public network while received messages are stripped of the "wrapper" and processed. This permits non-standard data (from an application like "Notes" or "AppleTalk") and totally encrypted messages to use the Internet. The technology is an important element in "Virtual Private Network" (VPN) offerings.

CACS/Glossary/MPLS. Multiprotocol Label Switching (MPLS) is a system of protocols that uses abbreviated routing information based on the devices and connections of a single "Internet Service Provider (ISP)". These abbreviated codes are then attached to an IP message to improve the speed and efficiency of internally routed messages. The protocols and their overall use are documented by the "IETF" in RFC3031.

CACS/Glossary/PKI. Public Key Infrastructure (PKI) An evolving system of "protocols" that define the "Digital Certificates" and "Certificate Authorities" that identify and validate the parties in an "electronic commerce" transaction to each other.

CACS/Glossary/Tunneling. Tunneling – a software process that uses "General Routing Encapsulation (GRE)" programs to send encrypted or incompatible messages over a network, usually the "Internet". The concept refers to the use of the internet by two nodes of a "Virtual Private Network (VPN)", and their treatment of the internet as a 'tunnel' for their messages.

CACS/Glossary/VPN. Virtual Private Network (VPN) a service, usually offered by an "ISP", that uses various routing, encryption, and security technologies to allow the Internet to serve as the equivalent of a private or controlled network. This supports the connection of a corporate network with external elements for telecommuting or extended enterprise applications, or may entirely replace a proprietary network. VPN is also used to describe the collective software and methods used in the VPN service.

CACS/Glossary/Adobe. Adobe Systems Inc. A software vendor specializing in documents. Founded in 1982, their best known products are "Pagemaker, Acrobat Reader," and "Photoshop". Located in San Jose, California, their web address is http://www.adobe.com/main.html.

CACS/Glossary/ADP. Automatic Data Processing (ADP) a corporation, specializing in payroll and "human resources" business services and founded in 1949. As of 2002 they grossed over $15 billion, Headquartered in Roseland, NJ, their web address is www.adp.com. .ADP is also a file extension for an Access Database Project.

Discrete Mathematics/Functions and relations. Introduction. This article examines the concepts of a "function" and a "relation". A relation is any association or link between elements of one set, called the domain or (less formally) the "set of inputs", and another set, called the range or "set of outputs". Some people mistakenly refer to the range as the "codomain"(range), but as we will see, that really means the "set of all possible outputs"—even values that the relation does not actually use. (Beware: some authors do not use the term "codomain"(range), and use the term "range" instead for this purpose. Those authors use the term image for what we are calling "range". So while it is a mistake to refer to the "range" or "image" as the "codomain"(range), it is not necessarily a mistake to refer to "codomain" as "range".) For example, if the "domain" is a set Fruits = {apples, oranges, bananas} and the "codomain"(range) is a set Flavors = {sweetness, tartness, bitterness}, the flavors of these fruits form a relation: we might say that apples are related to (or associated with) both sweetness and tartness, while oranges are related to tartness only and bananas to sweetness only. (We might disagree somewhat, but that is irrelevant to the topic of this book.) Notice that "bitterness", although it is one of the possible Flavors (codomain)(range), is not really used for any of these relationships; so it is not part of the "range" (or "image") {sweetness, tartness}. Another way of looking at this is to say that a relation is a "subset of ordered pairs" drawn from the "set of all possible ordered pairs" (of elements of two other sets, which we normally refer to as the "Cartesian product" of those sets). Formally, R is a relation if for the domain X and codomain(range) Y. The inverse relation of R, which is written as R-1, is what we get when we interchange the X and Y values: Using the example above, we can write the relation in set notation: {(apples, sweetness), (apples, tartness), (oranges, tartness), (bananas, sweetness)}. The inverse relation, which we could describe as "fruits of a given flavor", is {(sweetness, apples), (sweetness, bananas), (tartness, apples), (tartness, oranges)}. (Here, as elsewhere, the order of elements in a set has no significance.) One important kind of relation is the "function". A function is a relation that has exactly one output for every possible input in the domain. (The domain does not necessarily have to include all possible objects of a given type. In fact, we sometimes intentionally use a "restricted domain" in order to satisfy some desirable property.) The relations discussed above (flavors of fruits and fruits of a given flavor) are not functions: the first has two possible outputs for the input "apples" (sweetness and tartness); and the second has two outputs for both "sweetness" (apples and bananas) and "tartness" (apples and oranges). The main reason for not allowing multiple outputs with the same input is that it lets us apply the same function to different forms of the same thing without changing their equivalence. That is, if f is a function with a (or b) in its domain, then a = b implies that f(a) = f(b). For example, z - 3 = 5 implies that z = 8 because f(x) = x + 3 is a function unambiguously defined for all numbers x. The converse, that f(a) = f(b) implies a = b, is not always true. When it is, there is never more than one "input" x for a certain "output" y = f(x). This is the same as the definition of function, but with the roles of X and Y interchanged; so it means the "inverse relation" f-1 must also be a function. In general—regardless of whether or not the original relation was a function—the inverse relation will "sometimes" be a function, and sometimes not. When f and f-1 are both functions, they are called one-to-one, injective, or invertible functions. This is one of two very important properties a function f might (or might not) have; the other property is called onto or surjective, which means, for any y ∈ Y (in the codomain), there is some x ∈ X (in the domain) such that f(x) = y. In other words, a "surjective" function f "maps onto" every possible output at least once. A function can be neither one-to-one nor onto, both one-to-one and onto (in which case it is also called bijective or a one-to-one correspondence), or just one and not the other. (As an example which is neither, consider f = {(0,2), (1,2)}. It is a function, since there is only one y value for each x value; but there is more than one input x for the output y = 2; and it clearly does not "map onto" all integers.) Relations. In the above section dealing with functions and their properties, we noted the important property that all functions must have, namely that if a function does map a value from its domain to its co-domain, it must map this value to only one value in the co-domain. Writing in set notation, if "a" is some fixed value: The literal reading of this statement is: the "cardinality" (number of elements) of the set of all values f(x), such that x=a for some fixed value a, is an element of the set {0, 1}. In other words, the number of "outputs" that a function f may have at any fixed "input" a is either zero (in which case it is "undefined" at that input) or one (in which case the output is unique). However, when we consider the "relation", we relax this constriction, and so a relation may map one value to more than one other value. In general, a relation is any subset of the Cartesian product of its domain and co-domain. All functions, then, can be considered as relations also. Notations. When we have the property that one value is related to another, we call this relation a "binary relation" and we write it as where R is the relation. For arrow diagrams and set notations, remember for relations we do not have the restriction that functions do and we can draw an arrow to represent the mappings, and for a set diagram, we need only write all the ordered pairs that the relation does take: again, by example is a relation and not a function, since both 1 and 2 are mapped to two values, (1 and -1, and 2 and -2 respectively) example let A=2,3,5;B=4,6,9 then A*B=(2,4),(2,6),(2,9),(3,4),(3,6),(3,9),(5,4),(5,6),(5,9) Define a relation R=(2,4),(2,6),(3,6),(3,9) add functions and problems to one another. Some simple examples. Let us examine some simple relations. Say f is defined by This is a relation (not a function) since we can observe that 1 maps to 2 and 3, for instance. Less-than, "<", is a relation also. Many numbers can be less than some other fixed number, so it cannot be a function. Properties. When we are looking at relations, we can observe some special properties different relations can have. Reflexive. A relation is "reflexive" if, we observe that for all values a: In other words, all values are related to themselves. The relation of equality, "=" is reflexive. Observe that for, say, all numbers a (the domain is R): so "=" is reflexive. In a reflexive relation, we have arrows for all values in the domain pointing back to themselves: Note that ≤ is also reflexive (a ≤ a for any a in R). On the other hand, the relation < is not (a < a is false for any a in R). Symmetric. A relation is "symmetric" if, we observe that for all values of a and b: The relation of equality again is symmetric. If "x"="y", we can also write that "y"="x" also. In a symmetric relation, for each arrow we have also an opposite arrow, i.e. there is either no arrow between "x" and "y", or an arrow points from "x" to "y" and an arrow back from "y" to "x": Neither ≤ nor < is symmetric (2 ≤ 3 and 2 < 3 but neither 3 ≤ 2 nor 3 < 2 is true). Transitive. A relation is "transitive" if for all values "a", "b", "c": The relation "greater-than" ">" is transitive. If "x" > "y", and "y" > "z", then it is true that "x" > "z". This becomes clearer when we write down what is happening into words. "x" is greater than "y" and "y" is greater than "z". So "x" is greater than both "y" and "z". The relation "is-not-equal" "≠" is not transitive. If "x" ≠ "y" and "y" ≠ "z" then we might have "x" = "z" or "x" ≠ "z" (for example 1 ≠ 2 and 2 ≠ 3 and 1 ≠ 3 but 0 ≠ 1 and 1 ≠ 0 and 0 = 0). In the arrow diagram, every arrow between two values "a" and "b", and "b" and "c", has an arrow going straight from "a" to "c". Antisymmetric. A relation is "antisymmetric" if we observe that for all values "a" and "b": Notice that antisymmetric is not the same as "not symmetric." Take the relation "greater than or equal to", "≥" If "x" ≥ "y", and "y" ≥ x, then "y" must be equal to "x". a relation is anti-symmetric if and only if a∈A, (a,a)∈R Trichotomy. A relation satisfies "trichotomy" if we observe that for all values "a" and "b" it holds true that: "a"R"b" "or" "b"R"a" The relation "is-greater-or-equal" satisfies since, given 2 real numbers "a" and "b", it is true that whether "a" ≥ "b" or "b" ≥ "a" (both if "a" = "b"). Problem set. Given the above information, determine which relations are reflexive, transitive, symmetric, or antisymmetric on the following - there may be more than one characteristic. (Answers follow.) "x" R "y" if Equivalence relations. We have seen that certain common relations such as "=", and congruence (which we will deal with in the next section) obey some of these rules above. The relations we will deal with are very important in discrete mathematics, and are known as "equivalence relations". They essentially assert some kind of equality notion, or "equivalence", hence the name. Characteristics of equivalence relations. For a relation R to be an "equivalence relation", it must have the following properties, viz. R must be: In the previous problem set you have shown equality, "=", to be reflexive, symmetric, and transitive. So "=" is an equivalence relation. We denote an equivalence relation, in general, by formula_3. Example proof. Say we are asked to prove that "=" is an equivalence relation. We then proceed to prove each property above in turn (Often, the proof of transitivity is the hardest). Thus = is an equivalence relation. Partitions and equivalence classes. It is true that when we are dealing with relations, we may find that many values are related to one fixed value. For example, when we look at the quality of "congruence", which is that given some number "a", a number congruent to "a" is one that has the same remainder or "modulus" when divided by some number "n", as "a", which we write and is the same as writing For example, 2 ≡ 0 (mod 2), since the remainder on dividing 2 by 2 is in fact 0, as is the remainder on dividing 0 by 2. We can show that congruence is an equivalence relation (This is left as an exercise, below Hint use the equivalent form of congruence as described above). However, what is more interesting is that we can group all numbers that are equivalent to each other. With the relation congruence "modulo" 2 (which is using n=2, as above), or more formally: we can group all numbers that are equivalent to each other. Observe: This first equation above tells us all the "even" numbers are equivalent to each other under ~, and all the "odd" numbers under ~. We can write this in set notation. However, we have a special notation. We write: and we call these two sets "equivalence classes". All elements in an equivalence class by definition are equivalent to each other, and thus note that we do not need to include [2], since 2 ~ 0. We call the act of doing this 'grouping' with respect to some equivalence relation "partitioning" (or further and explicitly "partitioning a set S into equivalence classes under a relation ~"). Above, we have partitioned Z into equivalence classes [0] and [1], under the relation of congruence modulo 2. Problem set. Given the above, answer the following questions on equivalence relations (Answers follow to even numbered questions) formula_6 Partial orders. We also see that "≥" and "≤" obey some of the rules above. Are these special kinds of relations too, like equivalence relations? Yes, in fact, these relations are specific examples of another special kind of relation which we will describe in this section: the "partial order". As the name suggests, this relation gives some kind of ordering to numbers. Characteristics of partial orders. For a relation R to be a partial order, it must have the following three properties, viz R must be: We denote a partial order, in general, by formula_7. Question: Example proof. Say we are asked to prove that "≤" is a partial order. We then proceed to prove each property above in turn (Often, the proof of transitivity is the hardest). Reflexive. Clearly, it is true that "a" ≤ "a" for all values a. So ≤ is reflexive. Antisymmetric. If "a" ≤ "b", and "b" ≤ "a", then a "must" be equal to "b". So ≤ is antisymmetric Transitive. If "a" ≤ "b" and "b" ≤ "c", this says that "a" is less than "b" and "c". So "a" is less than "c", so "a" ≤ "c", and thus ≤ is transitive. Thus ≤ is a partial order. Problem set. Given the above on partial orders, answer the following questions Answers. 2. Simple proof; Formalization of the proof is an optional exercise. Posets. A partial order imparts some kind of "ordering" amongst elements of a set. For example, we only know that 2 ≥ 1 because of the partial ordering ≥. We call a set A, ordered under a general partial ordering formula_8, a "partially ordered set", or simply just "poset", and write it (A, formula_8). Terminology. There is some specific terminology that will help us understand and visualize the partial orders. When we have a partial order formula_8, such that "a" formula_8 "b", we write formula_19 to say that a formula_8 but "a" ≠ "b". We say in this instance that a "precedes" b, or "a" is a predecessor of "b". If (A, formula_8) is a poset, we say that "a" is an immediate predecessor of "b" (or "a" immediately precedes "b") if there is no "x" in A such that "a" formula_19 "x" formula_19 "b". If we have the same poset, and we also have "a" and "b" in A, then we say "a" and "b" are "comparable" if "a" formula_8 "b" or "b" formula_8 "a". Otherwise they are "incomparable". Hasse diagrams. "Hasse diagrams" are special diagrams that enable us to visualize the structure of a partial ordering. They use some of the concepts in the previous section to draw the diagram. A Hasse diagram of the poset (A, formula_8) is constructed by Operations on Relations. There are some useful operations one can perform on relations, which allow to express some of the above mentioned properties more briefly. Inversion. Let R be a relation, then its inversion, R-1 is defined by R-1 := {(a,b) | (b,a) in R}. Concatenation. Let R be a relation between the sets A and B, S be a relation between B and C. We can concatenate these relations by defining Diagonal of a Set. Let A be a set, then we define the diagonal (D) of A by Shorter Notations. Using above definitions, one can say (lets assume R is a relation between A and B): R is "transitive" if and only if R • R is a subset of R. R is "reflexive" if and only if D(A) is a subset of R. R is "symmetric" if R-1 is a subset of R. R is "antisymmetric" if and only if the intersection of R and R-1 is D(A). R is "asymmetric" if and only if the intersection of D(A) and R is empty. R is a "function" if and only if R-1 • R is a subset of D(B). In this case it is a function A → B. Let's assume R meets the condition of being a function, then R is "injective" if R • R-1 is a subset of D(A). R is "surjective" if {b | (a,b) in R} = B. Functions. A function is a relationship between two sets of numbers. We may think of this as a "mapping"; a function "maps" a number in one set to a number in another set. Notice that a function maps values to one and only one value. Two values in one set could map to one value, but one value must never map to two values: that would be a relation, "not" a function. For example, if we write (define) a function as: then we say: and we have and so on. This function f maps numbers to their squares. Range and codomain. If D is a set, we can say which forms a née of f is usually a subset of a larger set. This set is known as the "codomain" of a function. For example, with the function f("x")=cos "x", the range of f is [-1,1], but the codomain is the set of real numbers. Notations. When we have a function f, with domain D and range R, we write: If we say that, for instance, "x" is mapped to "x"2, we also can add Notice that we can have a function that maps a point ("x","y") to a real number, or some other function of two variables -- we have a set of ordered pairs as the domain. Recall from set theory that this is defined by the "Cartesian product" - if we wish to represent a set of all real-valued ordered pairs we can take the Cartesian product of the real numbers with itself to obtain When we have a set of "n"-tuples as part of the domain, we say that the function is "n"-ary (for numbers "n"=1,2 we say unary, and binary respectively). Other function notation. Functions can be written as above, but we can also write them in two other ways. One way is to use an arrow diagram to represent the mappings between each element. We write the elements from the domain on one side, and the elements from the range on the other, and we draw arrows to show that an element from the domain is mapped to the range. For example, for the function f("x")="x"3, the arrow diagram for the domain {1,2,3} would be: Another way is to use set notation. If f("x")="y", we can write the function in terms of its mappings. This idea is best to show in an example. Let us take the domain D={1,2,3}, and f("x")="x"2. Then, the range of f will be R={f(1),f(2),f(3)}={1,4,9}. Taking the Cartesian product of D and R we obtain F={(1,1),(2,4),(3,9)}. So using set notation, a function can be expressed as the Cartesian product of its domain and range. f("x") This function is called "f", and it takes a "variable" "x". We substitute some value for "x" to get the second value, which is what the function maps x to. Types of functions. Functions can either be one to one (injective), onto (surjective), or bijective. "INJECTIVE Functions" are functions in which every element in the domain maps into a unique elements in the codomain. "SURJECTIVE Functions" are functions in which every element in the codomain is mapped by an element in the domain. "'BIJECTIVE Functions" are functions that are both injective and surjective. ---onto functions a function f form A to B is onto ,

CACS/Glossary/Aldus. Aldus a former software vendor, noted for the developement of "Pagemaker", which was sold to "Adobe" in 1994.

CACS/Glossary/ANI. Animated Cursor – a feature that modifies the displayed "cursor" based on the state of the component the cursor is located in or the properties of a "control" that the cursor points to. State variation usually alters the cursor when a wait state exists. Property variation identifies controls or text that are accessible or available for end-user manipulation. The "file extension" .ANI is used for the graphics and conditions that control the display.

CACS/Glossary/Apache. Apache A free, open source Web Server "HTTP" processing software package from the "Apache Software Foundation". Apache runs on "OS/2, NetWare, Unix," and "Windows NT". Version 2.0 dates from May 2002. The software source code may be downloaded from the Apache Website, which also contains Apache Documentation. For Apache related questions or issues, you can search this large unofficial Apache Forum hosted by Nabble which currently archives all the Apache projects' mailing lists for cross search and browsing. You can also post your question to the appropriate sub forum which will then forward your post to the corresponding Apache mailing list.

CACS/Glossary/ASF. Apache Software Foundation A collaborative non-profit working group dedicated to the education, development and delivery of open source web software. Its Web address is the Apache Foundation.

CACS/Glossary/Application. An Application is: Typically, the application uses a single set of libraries and is considered a single project.

CACS/Glossary/Assembler. An Assembler is:

CACS/Glossary/Assembly. Assembly is the process of creating an executable module from assembly language source code. Sometimes assembly is used as a shorthand reference for "Assembly Language Code".

CACS/Glossary/ASML. Assembly Language is the lowest level of symbolic "progarmming language" characterized by the use of a single "statement" for each machine "instruction". The language also permits the use of labels for routines, variables, and storage assignments. There is a different language for each computer "CPU". Some versions of Assembly Language support the use of "Macro Instructions". Assembley Language source code is usually stored with a "file extension" of .ASM.

Esperanto/Contents. The Wikibooks Esperanto Textbook is a collaborative project to create an online open-content textbook for , which we hope will become the definitive Esperanto textbook for English speakers. About the book. __NOEDITSECTION__

CACS/User Conundrum. Wiki Note "This note will be removed later. The entire essay may become a secion within an Introduction Chapter. Or, it might remain here and just have an "assigned reading" on the introduction. Please use the Talk page for this entry for additional discussion. Thanks. " =The Myth of the User= There are several terms widely used in the computer industry that are not clearly defined. The result is that everyone understands them and uses them, but the use may tend to complicate rather than illuminate a discussion. This outline looks just two of these terms in the context of an application within a fairly large corporation. Then it draws some conclusions about the impact of context on the use of terminology. Consider the terms User and Application. The User is defined as "the person who uses a computer". The Platform is "the hardware or software that supports an application or a system". The suggested application is one of monitoring and use of a particular resource pool across an area of the company. The Application. Project and unit managers share a common resource pool. They budget and track the use of the pool in their area. They use a series of spreadsheets that show their planned vs. actual use of many resources. The data is extracted for their status reports. The data is also uploaded through the company's networks for use in other summaries of the effective use of the resource pool. These support the manager and planning staff that are responsible for the pool. To make this work, a set of spreadsheet macros are in place to ensure data validity and consistency. These templates are put in place by the corporate IT staff. The "end-user" needs to record their work results, using the spreadsheets by an arbitrary cutoff time on Friday. The Software Hierarchy. Now consider the hierarchy of software engineering that puts this application in place. The example could be extended further. The extensions in Step 3 could be produced by an outside "Value Added Reseller" to produce a resource planning system. Step 1 could look into the earlier history in Hardware for PC Configuration, BIOS, Operating Systems, The C++ compiler, etc. But these 5 layers are quite complex enough to illustrate the terminology problems. "For those who are have never worked in this situation, this is NOT an uncommon example. Millions of people work in this environment every day at your bank, your university, or the manufacturer of your automobile." The Confusion. The above example is fine when it works. But, what about when it fails? As the end-user, I've got a problem in my spreadsheet, and an error message. I find something from the 1st level, the "User's Guide", and try to find a solution. But it is a hopeless quest. I can't use most of the options they discuss. I can't even inspect the VBA code that the guide says my error message comes from. The usually helpful System Admin who put this new update on my desk is equally puzzled, and other users haven't reported a problem. So, what went wrong? Every layer in the hierarchy has their own viewpoint. Everything in the layers above them is viewed as a "Platform" and constitutes a given. Every participant in the layers below them is the User and is considered with the same monolithic view. In some cases, the monolithic view is correct, but even then it is usually distorted. When I buy a new PC for home use, I have the seemingly unfiltered copy of the spreadsheet. But even here, the software was preinstalled by the people I bought the PC from. They chose certain options left by the 1st level spreadsheet team to make the installed software work with this particular configuration. Certain other options may be precluded by their choices. A really good practitioner working in the hierarchy will be partially aware one layer above and below their own level. They can influence the layer above them, through user groups or other methods. They can consider the needs of those one layer below them, and improve their product and documentation to help out, but only as limited by budgets and competitive factors. Conclusions. If you begin to understand the problem, then Welcome to the world of Computers!. But you can also understand how many niches in this world open opportunities for integrators and vendors. How a "Peoplesoft" vendor can package and sell an integrated solution for a business function. How a high-powered consulting firm can charge high prices to help corporate management try to cope. Why the industry keeps looking for something like an "XML" magic wand to make it fit together. And most of all, how some kind of mental framework is needed before you can see how the pieces fit together. This kind of a framework is called an "Architecture", and several of them are needed to see how the pieces fit together.

Calculus/Ordinary differential equations. Ordinary differential equations involve equations containing: and their solutions. In studying integration, you "already" have considered solutions to very simple differential equations. For example, when you look to solving for g(x), you are really solving the differential equation Notations and terminology. The notations we use for solving differential equations will be crucial in the ease of solubility for these equations. This document will be using three notations primarily: Terminology. Consider the differential equation Since the equation's highest derivative is 2, we say that the differential equation is of "order" 2. Some simple differential equations. A key idea in solving differential equations will be that of integration. Let us consider the second order differential equation (remember that a function acts on a value). How would we go about solving this? It tells us that on differentiating twice, we obtain the constant 2 so, if we integrate twice, we should obtain our result. Integrating once first of all: We have transformed the apparently difficult second order differential equation into a rather simpler one, viz. This equation tells us that if we differentiate a function once, we get formula_9. If we integrate once more, we should find the solution. This is the "solution" to the differential equation. We will get formula_12 for "all" values of formula_13 and formula_14. The values formula_13 and formula_14 are related to quantities known as "initial conditions". Why are initial conditions useful? ODEs (ordinary differential equations) are useful in modeling physical conditions. We may wish to model a certain physical system which is initially at rest (so one initial condition may be zero), or wound up to some point (so an initial condition may be nonzero, say 5 for instance) and we may wish to see how the system reacts under such an initial condition. When we solve a system with given initial conditions, we substitute them after our process of integration. Example. When we solved formula_5 say we had the initial conditions formula_18 and formula_19. (Note, initial conditions need not occur at f(0)). After we integrate we make substitutions: Without initial conditions, the answer we obtain is known as the "general solution" or the solution to the "family of equations". With them, our solution is known as a "specific solution". Basic first order DEs. In this section we will consider "four" main types of differential equations: There are many other forms of differential equation, however, and these will be dealt with in the next section Separable equations. A "separable" equation is in the form (using dy/dx notation which will serve us greatly here) Previously we have only dealt with simple differential equations with g("y")=1. How do we solve such a separable equation as above? We group "x" and "dx" terms together, and "y" and "dy" terms together as well. Integrating both sides with respect to y on the left hand side and x on the right hand side: we will obtain the solution. Worked example. Here is a worked example illustrating the process. We are asked to solve Separating Integrating Letting formula_35 where k is a constant we obtain which is the general solution. Verification. This step does not need to be part of your work, but if you want to check your solution, you can verify your answer by differentiation. We obtained as the solution to Differentiating our solution with respect to x, And since formula_36, we can write We see that we obtain our original differential equation, thus our work must be correct. Homogeneous equations. A "homogeneous" equation is in the form This looks difficult as it stands, however we can utilize the substitution so that we are now dealing with F(v) rather than F(y/x). Now we can express y in terms of v, as "y"="xv" and use the product rule. The equation above then becomes, using the product rule Then which is a separable equation and can be solved as above. However let's look at a worked equation to see how homogeneous equations are solved. Worked example. We have the equation This does not appear to be immediately separable, but let us expand to get Substituting "y"="xv" which is the same as substituting "v"="y"/"x": Now Canceling "v" from both sides Separating Integrating both sides which is our desired solution. Linear equations. A linear first order differential equation is a differential equation in the form Multiplying or dividing this equation by any non-zero function of "x" makes no difference to its solutions so we could always divide by "a"("x") to make the coefficient of the differential 1, but writing the equation in this more general form may offer insights. At first glance, it is not possible to integrate the left hand side, but there is one special case. If "b" happens to be the differential of "a" then we can write and integration is now straightforward. Since we can freely multiply by any function, lets see if we can use this freedom to write the left hand side in this special form. We multiply the entire equation by an arbitrary, "I"("x"), getting then impose the condition If this is satisfied the new left hand side will have the special form. Note that multiplying "I" by any constant will leave this condition still satisfied. Rearranging this condition gives We can integrate this to get We can set the constant "k" to be 1, since this makes no difference. Next we use "I" on the original differential equation, getting Because we've chosen "I" to put the left hand side in the special form we can rewrite this as Integrating both sides and dividing by formula_67 we obtain the final result We call "I" an "integrating factor". Similar techniques can be used on some other calculus problems. Example. Consider First we calculate the integrating factor. Multiplying the equation by this gives or We can now integrate Exact equations. An exact equation is in the form and, has the property that (If the differential equation does not have this property then we can't proceed any further). As a result of this, if we have an exact equation then there exists a function h("x", "y") such that So then the solutions are in the form by using the fact of the total differential. We can find then h("x", "y") by integration Basic second and higher order ODE's. The generic solution of a "n"th order ODE will contain "n" constants of integration. To calculate them we need "n" more equations. Most often, we have either or Reducible ODE's. 1. If the independent variable, "x", does not occur in the differential equation then its order can be lowered by one. This will reduce a second order ODE to first order. Consider the equation: Define Then Substitute these two expression into the equation and we get which is a first order ODE Example. Solve if at "x"=0,  "y"=D"y"=1 First, we make the substitution, getting This is a first order ODE. By rearranging terms we can separate the variables Integrating this gives We know the values of "y" and "u" when "x"=0 so we can find "c" Next, we reverse the substitution and take the square root To find out which sign of the square root to keep, we use the initial condition, D"y"=1 at "x"=0, again, and rule out the negative square root. We now have another separable first order ODE, Its solution is Since "y"=1 when "x"=0, "d"=2/3, and 2. If the dependent variable, "y", does not occur in the differential equation then it may also be reduced to a first order equation. Consider the equation: Define Then Substitute these two expressions into the first equation and we get which is a first order ODE Linear ODEs. An ODE of the form is called linear. Such equations are much simpler to solve than typical non-linear ODEs. Though only a few special cases can be solved exactly in terms of elementary functions, there is much that can be said about the solution of a generic linear ODE. A full account would be beyond the scope of this book If "F(x)=0" for all "x" the ODE is called homogeneous Two useful properties of generic linear equations are Variation of constants. Suppose we have a linear ODE, and we know one solution, "y=w(x)" The other solutions can always be written as "y=wz". This substitution in the ODE will give us terms involving every differential of "z" upto the "n"th, no higher, so we'll end up with an "n"th order linear ODE for "z". We know that "z" is constant is one solution, so the ODE for "z" must not contain a "z" term, which means it will effectively be an "n-1"th order linear ODE. We will have reduced the order by one. Lets see how this works in practice. Example. Consider One solution of this is "y=x2", so substitute "y=zx2" into this equation. Rearrange and simplify. This is first order for D"z". We can solve it to get Since the equation is linear we can add this to any multiple of the other solution to get the general solution, Linear homogeneous ODE's with constant coefficients. Suppose we have a ODE we can take an inspired guess at a solution (motivate this) For this function Dn"y"=pny so the ODE becomes "y=0" is a trivial solution of the ODE so we can discard it. We are then left with the equation This is called the "characteristic" equation of the ODE. It can have up to "n" roots, p1, p2 … pn, each root giving us a different solution of the ODE. Because the ODE is linear, we can add all those solution together in any linear combination to get a general solution To see how this works in practice we will look at the second order case. Solving equations like this of higher order uses exactly the same principles; only the algebra is more complex. Second order. If the ODE is second order, then the characteristic equation is a quadratic, with roots What these roots are like depends on the sign of "b"2-4"c", so we have three cases to consider. "1) b2 > 4c" In this case we have two different real roots, so we can write down the solution straight away. "2) b2 < 4c" In this case, both roots are imaginary. We could just put them directly in the formula, but if we are interested in real solutions it is more useful to write them another way. Defining k2=4c-b2, then the solution is For this to be real, the "A"'s must be complex conjugates Make this substitution and we can write, If "b" is positive, this is a damped oscillation. "3) b2 = 4c" In this case the characteristic equation only gives us one root, "p=-b/2". We must use another method to find the other solution. We'll use the method of variation of constants. The ODE we need to solve is, rewriting "b" and "c" in terms of the root. From the characteristic equation we know one solution is formula_100 so we make the substitution formula_113, giving This simplifies to D2"z"=0, which is easily solved. We get so the second solution is the first multiplied by "x". Higher order linear constant coefficient ODE's behave similarly: an exponential for every real root of the characteristic and a exponent multiplied by a trig factor for every complex conjugate pair, both being multiplied by a polynomial if the root is repeated. E.g., if the characteristic equation factors to the general solution of the ODE will be The most difficult part is finding the roots of the characteristic equation. Linear nonhomogeneous ODEs with constant coefficients. First, let's consider the ODE a nonhomogeneous first order ODE which we know how to solve. Using the integrating factor "e-x" we find This is the sum of a solution of the corresponding homogeneous equation, and a polynomial. Nonhomogeneous ODE's of higher order behave similarly. If we have a single solution, "yp" of the nonhomogeneous ODE, called a "particular" solution, then the general solution is "y=yp+yh", where "yh" is the general solution of the homogeneous ODE. Find "yp" for an arbitrary "F(x)" requires methods beyond the scope of this chapter, but there are some special cases where finding "yp" is straightforward. Remember that in the first order problem "yp" for a polynomial "F(x)" was itself a polynomial of the same order. We can extend this to higher orders. "Example:" Consider a particular solution Substitute for "y" and collect coefficients So "b2=0", "b1=-7", "b0=1", and the general solution is This works because all the derivatives of a polynomial are themselves polynomials. Two other special cases are where "Pn","Qn","An", and "Bn" are all polynomials of degree "n". Making these substitutions will give a set of simultaneous linear equations for the coefficients of the polynomials.

CACS/Glossary/Basic. Basic Language is a high level computer language that was intrroducd with the PC in the 1960s. BASIC is an acronym for Beginner's All-purpose Symbolic Instruction Code. Basic was originally an , but compilers were soon introduced. While there is an "ANSI Standard" Basic, most vendors use proprietary extensions. There is a subset or similar language used in "Web pages" called "Basic Script." Microsoft platform applications include another subset called "Visual Basic for Applications (VBA)". The .BAS "file extension" is frequently used for Basic source code.

CACS/Glossary/Binary. Binary is a number system in the base 2, which contains only the digits 0 and 1. Since computer memory is made up of off-on switches, all computer programs and data are ultimately encoded in binary. Binary refers to a program that has been compiled into an executable module. When the module is stored, the .BIN "file extension" is used. Some development platform compilers produce a binary module that must still be "linked" with other modules to produce an executable program.

CACS/Glossary/Borland. Borland is a software developer and vendor specializing in development tools, language compilers, and data base platforms. It was founded in 1983, and is located in Scotts Valley, California. Their Web address is Borland.com.

CACS/Glossary/Computer. A Computer is programmable machine containing memory, input and output devices, and a "central processor (CPU)"; and capable of executing a stored program. Each computer has a well defined "instruction set" that is used in "programming" it.

Spanish/Typing Spanish Characters. Windows. Language Settings (fastest). The idea of changing the language settings is that you can then type characters quickly and easily (for example by pressing Alt+a for typing á). Windows XP. This is a list that describes how to change the language settings for Windows XP. Now you should see a keyboard icon at your task bar at the bottom. Click on this icon to switch to the United States International keyboard layout. This keyboard layout has a new key (AltGr) and 5 "dead keys". The dead keys are explained below. An interactive diagram of this layout can be found in . The US International keyboard has two different Alt keys. The left Alt key continues to be the regular Alt key, normally associated with Windows menus. The right Alt key becomes what is called AltGr (or graphic Alt) key. This key lets you type very quickly special characters in Spanish and other languages by using "AltGr" and then typing a character from the list below. Note: + indicate typing one key after the other. - is typing two keys at the same time. Lower-Case Characters. á -> AltGr+a é -> AltGr+e í -> AltGr+i ó -> AltGr+o ú -> AltGr+u ü -> AltGr+y ñ -> AltGr+n ç -> AltGr+, å -> AltGr+w Upper-Case Characters. Á -> AltGr+Shift-a É -> AltGr+Shift-e Í -> AltGr+Shift-i Ó -> AltGr+Shift-o Ú -> AltGr+Shift-u Ü -> AltGr+Shift-y Ñ -> AltGr+Shift-n Ç -> AltGr+Shift-, Ð -> AltGr+Shift-d Other Symbols. ¿ -> AltGr+? ¡ -> AltGr+! « -> AltGr+[ Spaniards prefer «angular» quotes » -> AltGr+] Latin Americans prefer the “curly” ones ° -> AltGr+: Degree sign; ordinal sign, as in "4° año = cuarto año" € -> AltGr+5 ¢ -> AltGr+Shift-c £ -> AltGr+$ ¥ -> AltGr+- Dead Keys. The US International keyboard has five "dead keys". They add the symbol they have marked at the top of the following letter. '+a = á; '+e = é; ... "+a = ä; ...; "+u = ü ~+a = ã; ~+n = ñ ^+a = â; ... `+a = à; ... '+Shift-a = Á; '+Shift+e = É; ... "+Shift-u = Ü; ... ~+Shift-n = Ñ; ... To enter what's written on a dead key you need to add a space. ' followed by space generates an actual apostrophe. Other Operating Systems. Information on some other operation systems can be found here. Alt Number Codes. You can type a special character by pressing and holding down the "Alt" button and then typing a number code on the number pad of your keyboard. The most frequently used characters have both a three-digit and a four-digit code. Less frequent characters (such as Á) have only a four-digit code. This page contains a good overview of special characters for different languages Lower Case Characters. á -> Alt-160 or Alt-0225 ç -> Alt-135 or Alt-0231 é -> Alt-130 or Alt-0233 í -> Alt-161 or Alt-0237 ñ -> Alt-164 or Alt-0241 ó -> Alt-162 or Alt-0243 ú -> Alt-163 or Alt-0250 ü -> Alt-129 or Alt-0252 Upper Case Characters. Á -> Alt-0193 Ç -> Alt-128 or Alt-0199 É -> Alt-144 or Alt-0201 Í -> Alt-0205 Ñ -> Alt-165 or Alt-0209 Ó -> Alt-0211 Ú -> Alt-0218 Ü -> Alt-154 or Alt-0220 Punctuation Marks. ¿ Alt-168 or Alt-0191 ¡ Alt-173 or Alt-0161 Copy & Paste. This method can be useful if you are just writing a short text (for example an e-mail) and don't have a computer where you can/want change language settings. Just try to pull up a web page or a document that contains the special characters and paste them into your text. For longer texts, however, this can become quite tedious. Search & Replace. If you are working with a text editor you have the option to search for text and replace it with other text. This feature can be used to 'type' special characters. The idea is to "mark" a character for becoming a special character, for example typing "~a" when you mean "á". After you have written your text you replace marked characters (the "~a") with special characters (the "á"). Of course you have to either type in the Alt number code or paste the character, but the point is that you only have to do it "once" for the whole text and not for every single "á" that you want to type. Automated Search & Replace. If you know a programming language that allows string processing you can automate the "Search & Replace" process by a computer program which automatically replaces all your marked characters with the appropriate special characters after you are done with typing your text. Macintosh. Compared to Windows, typing Spanish characters on a Macintosh is relatively easy. So long as you are using a standard American or UK-style QWERTY keyboard, you may just use the following keyboard commands. (Note that you should release the Option (Opt) key before striking the second letter; for example, for á, hold down Option, strike E, release Option, strike A.) One good way to practice typing Spanish characters on a Mac is to use the Key Caps program, which should be in the Utilities folder in the Applications folder. This simple program will show you what characters you can type next if you hold down the Option and/or Shift keys. Lower-Case Characters. á -> Opt+E, A é -> Opt+E, E í -> Opt+E, I ó -> Opt+E, O ú -> Opt+E, U ü -> Opt+U, U ñ -> Opt+N, N ç -> Opt+C å -> Opt+A Upper-Case Characters. Á -> Opt+E, Shift+A É -> Opt+E, Shift+E Í -> Opt+E, Shift+I Ó -> Opt+E, Shift+O Ú -> Opt+E, Shift+U Ü -> Opt+U, Shift+U Ñ -> Opt+N, Shift+N Ç -> Opt+Shift+C Other Symbols. ¿ -> Opt+Shift+/ (forward slash; same key as ?) ¡ -> Opt+1 « -> Opt+\ (back slash; under the Delete key) » -> Opt+Shift+\ *Note that Spaniards prefer «angle quotes,» whereas Latin Americans prefer “curly quotes” as in English. ° -> Opt+Shift+8 Degree sign; ordinal sign, as in "4° año = cuarto año" € -> Opt+Shift+2 ¢ -> Opt+4 £ -> Opt+3 ¥ -> Opt+Y KDE/GNOME. In KDE and GNOME you can choose the international US keyboard layout. In KDE, go to Regional & Accessibility - Keyboard Layout in the "KDE Control Center". Add the international US keyboard layout to your active layouts. With the flag icon in your taskbar you can now switch between different layouts. In GNOME, find preferences in the system menu, and select "keyboard" from the preferences menu. Add the US English International layout to your layouts. Alt+Alt will cycle through the various layouts you have added. Alternatively, keyboard layout selection and management may be done via the GNOME "keyboard indicator" applet, which may be added to your panel. With the appropriate keyboard layout selected, you can type á by typing ' and then a: 'a á 'e é 'i í 'o ó 'u ú "u ü ~n ñ X Windows. In X Windows (the default windowing system for Linux which both KDE and Gnome run on top of) you can create a custom X keyboard layout with the special Spanish letters added; more information is here.

Spanish/Web Resources. Leer en línea (read online). Todos los enlaces llevan a páginas en español ("all links go to Spanish language pages"). Software (software). www.spanishconversationclub.com (Spansih as foreign language conversation club in London)

Spanish/History. Here is a little history about the development of this Wikibook, detailing milestones since the beginning of the project.

Biochemistry/Thermodynamics. Why Do Substances React? Chemical (and thus, biochemical) reactions only occur to a significant extent if they are energetically favorable. If the products are more stable than the reactants, then in general the reaction will, over time, tend to go forward. Ashes are more stable than wood, so once the energy of activation is supplied (e.g., by a match), the wood will burn. There are plenty of exceptions to the rule, of course, but as a rule of thumb it's pretty safe to say that if the products of a reaction represent a more stable state, then that reaction will go in the forward direction. There are two factors that determine whether or not reactions changing reactants into products are considered to be "favorable": these two factors are simply called enthalpy and entropy. Enthalpy. Simply put, enthalpy is the heat content of a substance ("H"). Most people have an intuitive understanding of what heat is... we learn as children not to touch the burners on the stove when they are glowing orange. Enthalpy is not the same as that kind of heat. Enthalpy is the sum of all the internal energy of a substance's matter plus its pressure times its volume. Enthalpy is therefore defined by the following equation: where (all units given in SI) If the enthalpy of the reactants while being converted to products ends up decreasing (Δ"H" < 0), that means that the products have less enthalpy than the reactants and energy is released to the environment. This reaction type is termed "exothermic". In the course of most biochemical processes there is little change in pressure or volume, so the change in enthalpy accompanying a reaction generally reflects the change in the internal energy of the system. Thus, exothermic reactions in biochemistry are processes in which the products are lower in energy than the starting materials. As an example, consider the reaction of glucose with oxygen to give carbon dioxide and water. Strong bonds form in the products, reducing the internal energy of the system relative to the reactants. This is a highly exothermic reaction, releasing 2805 kJ of energy per mole of glucose that burns (Δ"H" = -2805 kJ/mol). That energy is given off as heat. Entropy. Entropy (symbol "S") is the measure of randomness in something. It represents the most likely of statistical possibilities of a system, so the concept has extremely broad applications. In chemistry of all types, entropy is generally considered important in determining whether or not a reaction goes forward based on the principle that a less-ordered system is more statistically probable than a more-ordered system. What does that mean, really? Well, if the volcano Mt. Vesuvius erupted next to a Roman-Empire era Mediterranean city, would the volcano be more likely to destroy the city, or build a couple of skyscrapers there? It's pretty obvious what would happen (or, rather, what "did" happen) because it makes sense to us that natural occurrences favor randomness (destruction) over order (construction, or in this case, skyscrapers). Entropy is just a mathematical way of expressing these essential differences. When it comes to chemistry, there are three major concepts based on the concept of entropy: Changes in entropy are denoted as ΔS. For the reasons stated above (in the volcano situation), the increase of entropy (ΔS > 0) is considered to be favorable as far as the Universe in general is concerned. A decrease in entropy is generally not considered favorable unless an energetic component in the reaction system can make up for the decrease in entropy (see free energy below). Gibbs Free Energy. Changes of both enthalpy (ΔH) and entropy (ΔS) combined decide how favorable a reaction is. For instance, burning a piece of wood releases energy ("exothermic", favorable) and results in a substance with less structure (CO2 and H2O gas, both of which are less 'ordered' than solid wood). Thus, one could predict that once a piece of wood was set on fire, it would continue to burn until it was gone. The fact that it does so is ascribed to the change in its Gibbs Free Energy. The overall favorability of a reaction was first described by the prominent chemist Josiah Willard Gibbs, who defined the "free energy" of a reaction as where T is the temperature on the Kelvin temperature scale. The formula above assumes that pressure and temperature are constant during the reaction, which is almost always the case for biochemical reactions, and so this book makes the same assumption throughout. The unit of ΔG (for "Gibbs") is the "joule" in SI systems, but the unit of "calorie" is also often used because of its convenient relation to the properties of water. This book will use both terms as convenient, but the preference should really be for the SI notation. What Does ΔG Really Mean? If ΔG < 0 then the reactants should convert into products (signifying a forward reaction)... eventually. (Gibbs free energy says nothing about a reaction's "rate", only its "probability".) Likewise, for a given reaction if ΔG > 0 then it is known that the reverse reaction is favored to take place. A state where ΔG = 0 is called equilibrium, and this is the state where the reaction in both the forward and reverse directions take place at the same rate, thus not changing the net effect on the system. How is equilibrium best explained? Alright, as an example set yourself on the living room carpet with your most gullible younger relative (a little nephew, niece or cousin will work fine). Take out a set of Monopoly, take one ten dollar bill for yourself and give your little relative the rest. Now both of you give the other 5% of all that you have. Do this again, and again, and again-again-again until eventually... you both have the same amount of money. This is precisely what the equilibrium of a reaction means, though equilibrium only very rarely results in an even, 50-50% split of products and reactants. ΔG naturally varies with the concentration of reactants and products. When ΔG reaches 0, the reaction rate in the forward direction and the reaction rate in the reverse direction are the same, and the concentration of reactants and products no longer appears to change; this state is called the "point of chemical equilibrium". You and your gullible little relative have stopped gaining and losing Monopoly money, respectively; you both keep exchanging the same amount each turn. Note again that equilibrium is "dynamic". Chemical reaction does not cease at equilibrium, but products are converted to reactants and reactants are converted to products at exactly the same rate. A small ΔG (that is, a value of ΔG close to 0) indicates that a reaction is somewhat reversible; the reaction can actually run backwards, converting products back to reactants. A very large ΔG (that is, ΔG » 0 or ΔG « 0) is precisely the opposite, because it indicates that a given reaction is irreversible, i.e., once the reactants become products there are very few molecules that go back to reactants. Metabolic pathways. The food we consume is processed to become a part of our cells; DNA, proteins, etc. If the biochemical reactions involved in this process were reversible, we would convert our own DNA back to food molecules if we stop eating even for a short period of time. To prevent this from happening, our "metabolism" is organized in "metabolic pathways". These pathways are a series of biochemical reactions which are, as a whole, irreversible. The reactions of a pathway occur in a row, with the products of the first reaction being the reactants of the second, and so on: At least one of these reactions has to be irreversible, e.g.: The control of the irreversible steps (e.g., A → B) enables the cell to control the whole pathway and, thus, the amount of reactants used, as well as the amount of products generated. Some metabolic pathways do have a "way back", but it is not the same pathway backwards. Instead, while using the reversible steps of the existing pathway, at least one of the irreversible reactions is bypassed by another (irreversible) one on the way back from E to A: This reaction is itself controlled, letting the cell choose the direction in which the pathway is running. Free energy and equilibrium. For ΔG, the free energy of a reaction, standard conditions were defined: Under these standard conditions, ΔG0' is defined as the standard free energy change. For a reaction the ratio of products to reactants is given by keq' (=keq at pH 7.0): The relationship of ΔG0' and keq' is with In theory, we can now decide if a reaction is favorable (ΔG0' < 0). However, the reaction might need a "catalyst" to occur within a reasonable amount of time. In biochemistry, such a catalyst is called an "enzyme". The purpose of DNA melting or DNA denaturation is emphasizing and demonstrating the life cycles of all organisms and the origin of replication. The origin of replication specific structure varies from species to species. Furthermore, the particular sequence of the origin of replication is in a genome which is the human genes. Nevertheless, DNA replication is also part of origin of replication which examen in the living organism such as prokaryotes and eukaryotes. Thermodynamically, there are two important contributions on the DNA denaturation. One of them is the breaking all of the hydrogen bonds between the bases in the double helix; the other one is to overcome the stacking stability/energy of bases on top of each other. There are several methods to denature DNA; heat is known as the most common one use in laboratory. We just have to heat the sample to reach above its melting point, the unstack ability of DNA can be then monitored. Melting point and denaturation of DNA depend on several factors: the length of DNA, base-composition of DNA, the condition of the DNA and also the composition of buffer. For instance, the longer DNA will contain more H-bonds and more intermolecular forces compared to the shorter one; therefore, denaturations of longer DNA requires more time and more heat. Base-composition of DNA can also play as a key factor because A:T requires two hydrogen bonds and G:C interaction requires three hydrogen bonds. The region of DNA which contains more A:T will melt/denature more rapidly compared to G:C. We can also see how the condition of DNA is important because condition of DNA is related to whether the DNA is relax, supercoiled, linear or heavily nicked. It is important because it allow us to examine how much intermolecular forces existing in the double helix. Finally, condition of buffer is also playing an essential role to study DNA denaturation because it allow us to control the amount of ions present in the solution during the entire process. Biologically, DNA denaturation can happen inside the cell during DNA replication or translation. In both cases, DNA denaturation is an essential step and a beginning to start each of the process. Most of the time, denaturation happened because of binding of protein or enzymes to a specific region of DNA, the binding will likely lead to open or denature of the helix. However, the actual meaning of the DNA melting is the denaturation of DNA which changes the structure of DNA from double stranded into single stranded. The processes of DNA denaturation is unwinding the double stranded deoxyribonucleic acid and breaks it into two single stranded by breaking the hydrogen bonding between the bases. DNA denaturation is also known of DNA annealing because it is reservable . The main steps DNA annealing are double helical will go through the denaturation to become partially denatured DNA then it will separated the strands into two single strand of DNA in random coils.

Cell Biology/Organelles. ../Parts of the cell/ Organelles: (1) nucleolus (2) nucleus (3) ribosome (4) vesicle (5) rough endoplasmic reticulum (ER) (6) Golgi apparatus (7) Cytoskeleton (8) smooth ER (9) mitochondrion (10) vacuole (11) cytoplasm (12) lysosome (13) centrioles (14) vacuole Nucleus. The nucleus contains genetic material or DNA in the form of chromatin, or, during mitosis or late interphase, chromosomes. All transcription and replication of genetic material take place within the nucleus, as does RNA processing. The nucleolus also resides within the nucleus and is responsible for RNA transcription and folding. Translation of RNA transcripts takes place outside of the nucleus. Mitochondria. A mitochondrian is the organelle responsible for a cell's metabolism. It synthesizes ATP through a protein called ATP synthase. Mitochondria have a double membrane. An outer membrane and a folded inner membrane. The internal membrane, called the cristae is invaginated (folded or creased), to maximize surface area enabling it to hold more ATP syntheses. It is called as "the powerhouse of the cell" which is present in the eukaryotic organisms. It has matrix inside the inner membrane. It is in a rod shape structure. Ribosomes. Ribosomes are responsible for protein synthesis. They are comprised of interacting protein and nucleic acid chains. Broadly, ribosomes are comprised of a large and a small subunit. The small subunit functions to attach to the mRNA strand and hold it in place during translation, while the large subunit holds and manufactures the growing polypeptide chain. The large subunit is further subdivided into the A (aminoacyl), P (peptidyl), and E (exit) binding sites. Aminoacyl Binding Site The aminoacyl binding site binds a charged tRNA whose anticodon matches the codon in the A site. Peptidyl Binding Site The peptidyl binding site contains the molecular machinery that transfers the bound polypeptide from the tRNA to the polypeptide chain, and holds the growing chain in place. Exit Site The exit site is the terminal binding site for tRNA, where discharged tRNA's are released from the translation complex. Endoplasmic Reticulum. The Endoplasmic Reticulum (ER) acts as a transport from the nucleus and ribosomes to the Golgi apparatus. There are two types of endoplasmic reticulum: Smooth ER. Smooth ER act as transport for various things, mainly the RNA from the nucleus to the ribosomes (RNA is a small piece of the DNA code specifically designed to tell the ribosomes what to make). Smooth ER appears smooth in texture, hence the name. Smooth ER plays an important role in lipid emulsification and digestion in the cell. Rough ER. Rough ER are "rough" because of the ribosomes embedded in them. The rough ER takes the protein to the Golgi apparatus to be packaged into vacuoles Golgi Complex(apparatus). The Golgi Complex basically functions as a "packaging center" for the cell, attaching "address labels" (functional groups) to various cell products to direct them to their respective locations, and "packaging" the products into vacuoles to ensure delivery. Anatomically, the Golgi Complex consists of layers of lipid membrane stacked one on top of another, with a cis face and a trans face. As the molecular product being packaged moves through the complex, various enzymes act upon it to induce vacuole formation and functional group attachment. <br> Vacuole. Vacuoles are cellular storage places. Like the cell membrane, they are comprised of a lipid bilayer that functions as a selectively permeable barrier to regulate movement of materials into and out of the compartment. They can serve a variety of purposes, storing food, water, or waste products, or immune functions such as containing dangerous materials or maintaining turgor pressure (in plants). Vacuoles serve very different purposes in plant cells than they do in animal cells. Plant Cells In plants, vacuoles comprise a significant portion of the cell's total volume and often contribute significantly to the function of a differentiated cell. For example, vacuoles in stomata cells contain large numbers of potassium ions, which can be pumped in or out to open or close the stomata. Animal Cells In animal cells, vacuoles serve more subordinate roles, such as assisting in endo- and exocytosis or basic storage of food and waste. Central Vacuole The central vacuole is found only in plant cells. It is filled with water and is pressurised, like a balloon. This forces all the other organelles within the cell out toward the cell wall. This pressure is called "turgor pressure" and is what gives plants their "crisp" and firm structure. Peroxisomes. Peroxisomes perform a variety of metabolic processes and as a by-product, produce hydrogen peroxide. Peroxisomes use peroxase enzyme to break down this hydrogen peroxide into water and oxygen. Lysosomes. Lysosomes are vacuoles containing digestive and destructive membranes. In white blood cells, these are used to kill the bacteria or virus, while in tadpole-tail cells they kill the cell by separating the tail from the main body. They also do much of the cellular digestion involved in apoptosis, the process of programmed cell death.

Cell Biology/Genetic material. Cell Biology | Parts of the cell

Cell Biology/Energy supply. ../Parts of the cell/ Chloroplasts are the organelles used for photosynthesis (a process that incorporates light energy into storage as chemical energy) whereas mitochondria used in respiration (a process that releases stored chemical energy). It assumed that you already know the information about these organelles explained in the organelles section. If you have not read the entries on chloroplasts and mitochondria from there yet, please go back and read them now.

Cell Biology/Introduction/What is a cell. Cells are structural units that make up plants and animals; also, there are many single celled organisms. What all living cells have in common is that they are small 'sacks' composed mostly of water. The 'sacks' are made from a phospholipid bilayer membrane. This membrane is semi-permeable (allowing some things to pass in or out of the cell while blocking others). There exist other methods of transport across this membrane that we will get into later. So what is in a cell? Cells are 90% fluid (called cytoplasm) which consists of free amino acids, proteins, carbohydrates, fats, and numerous other molecules. The cell environment (i.e., the contents of the cytoplasm and the nucleus, as well as the way the DNA is packed) affect gene expression/regulation, and thus are VERY important aspects of inheritance. Below are approximations of other components (each component will be discussed in more detail later): Components of cytoplasm. The following is optional reading, as all cell components will be discussed in subsequent chapters.

Cell Biology/Introduction/Cell size. Size of Cells. Although it is generally the case that biological cells are too small to be seen at all without a microscope, there are exceptions as well as considerable range in the sizes of various cell types. Eukaryotic cells are typically 10 times the size of prokaryotic cells (these cell types are discussed in the next Chapter). Plant cells are on average some of the largest cells, probably because in many plant cells the inside is mostly a water filled vacuole. So, you ask, what are the relative sizes of biological molecules and cells? The following are all approximations: 0.1 nm (nanometer) diameter of a hydrogen atom 0.8 nm Amino Acid 2 nm Diameter of a DNA Alpha helix 4 nm Globular Protein 6 nm microfilaments 7 nm thickness cell membranes 20 nm Ribosome 25 nm Microtubule 30 nm Small virus (Picornaviruses) 30 nm Rhinoviruses 50 nm Nuclear pore 100 nm HIV 120 nm Large virus (Orthomyxoviruses, includes influenza virus) 150-250 nm Very large virus (Rhabdoviruses, Paramyxoviruses) 150-250 nm small bacteria such as Mycoplasma 200 nm Centriole 200 nm (200 to 500 nm) Lysosomes 200 nm (200 to 500 nm) Peroxisomes 800 nm giant virus Mimivirus 1 µm (micrometer) (1 - 10 µm) the general sizes for Prokaryotes 1 µm Diameter of human nerve cell process 2 µm E.coli - a bacterium 3 µm Mitochondrion 5 µm length of chloroplast 6 µm (3 - 10 micrometers) the Nucleus 9 µm Human red blood cell 10 µm (10 - 30 µm) Most Eukaryotic animal cells (10 - 100 µm) Most Eukaryotic plant cells 90 µm small Amoeba 120 µm Human Egg up to 160 µm Megakaryocyte up to 500 µm giant bacterium Thiomargarita up to 800 µm large Amoeba 1 mm (1 millimeter, 1/10th cm) 1 mm Diameter of the squid giant nerve cell up to 40mm Diameter of giant amoeba Gromia Sphaerica 120 mm Diameter of an ostrich egg (a dinosaur egg was much larger) 3 meters Length of a nerve cell of giraffe's neck What limits cell sizes?

Cell Biology/Introduction/The elements of life. The various elements that make up the cell are: The difference between these elements is their respective atomic weights, electrons, and in general their chemical properties. A given element can only have so many other atoms attached. For instance carbon (C) has 4 electrons in its outer shell and thus can only bind to 4 atoms; Hydrogen only has 1 electron and thus can only bind to one other atom. An example would be Methane which is CH4. Oxygen only has 2 free electrons, and will sometimes form a double bond with a single atom, which is an 'ester' in organic chemistry (and is typically scented). As for the organic molecules that make up a typical cell: Here is a list of Elements, symbols, weights and biological roles.

Cell Biology/Introduction/What is living. The question, "What is life?" has been one of many long discussions and the answer may depend upon your initial definitions. Life is cells. Cell theory consists of three basic points. Some definitions of life are: Seven Criteria. In biology, whether life is present is determined based on the following seven criteria: Another way of remembering the seven life processes for children is:- Movement Respiration Sensitivity Growth Reproduction Excretion Nutrition Note the beginning letter of all the seven life processes, it spells out MRS GREN. Virus Controversy. This definition of life has got some problems to it though: As an example, let's take viruses. Just by your intuition, what would you say: Are viruses alive or dead? Most people's intuitive answer is: Viruses are alive. When we suffer from any viral infection, we have the feeling that these viruses that cause our infection are alive. According to the seven principles as shown above, viruses are dead, as dead as a piece of plastic: They can't reproduce themselves. To understand that, we want to make a quick excursion to the replication mechanism of viruses: Viruses are really strange in their reproduction technique. Humans and other animals reproduce by the means of sexual intercourse, bacteria do something called binary fission: They divide. One cell divides itself into two, the two daughter cells divide again an so on. The point here is that both bacteria and animals or humans reproduce actively without any help from outside. Keep this point in mind as we move on to the viruses. Viruses need other cells to reproduce. They "drill" their way into another cell, called the host cell. Here, they release the genetic material they carry and, by a complex mechanism that shouldn't be explained further at this point, force their host cell to produce exact copies of the virus. After some time, the host cell is full of viruses and bursts, releasing the new viruses into the environment. Thus viruses need help to reproduce. They can't reproduce at all without a host cell and therefore do not fulfill the requirement "It should be able to reproduce itself". Looking at the other parts of the definition we find that viruses maintain some degree of homeostasis (1), being able to keep its protenatious and nucleic machinery separated from the outside world. Viruses also show adaptation(5), with their ability to mutate in order to affect new organisms. In addition to the reproduction problem, they also fail to meet the other requirements, showing no cellular organization (2) (or indeed cells at all), metabolism (3), or growth (4). This example is just to illustrate the problems that arise using this definition. Life is not something one can define as any other technical term in science. Life arose from dead matter around 4 billion years ago. When life can arise from dead matter, there can't be a precise border line between these two. The cell is alive, what about parts of it? Organelles are parts of eukaryotic cells (ones having a nucleus). They help the cell carry out its task. But, are they alive? Do they meet 7 criteria? When a cell divides into two, organelles also 'reproduce'. They also age from young to old and then die. Some of them carry out the task of taking food, converting it to nutrients and energy. They can also react to stimuli, and surely they can evolve. Of course one can argue that all the above are coordinated by the nucleus. But it seems there are some signs of life there. Yes, there are! Scientists have proven that some bacteria, in its evolutionary way, had found a home in other cells. They felt comfortable when living there, and gradually, they have become a part of that cell. Chloroplasts, for example, used to be bacteria. At some point in their evolutionary history these cyanobacteria formed a mutual symbiosis with the proto-eukaryote ancestors of algae. Since that time, chloroplasts have been helping plant cells photosynthesize. Another example is mitochondria, organelles that produce energy for eukaryotes. Very likely a parasitic organism originally, the ancestor of the mitochondria we see today colonized the larger proto-eukarotes. It is unknown if the mitochondrial ancestor originally had a metabolic role in its life cycle or if it adapted to the changing conditions after it was engulfed.

Cell Biology/Introduction/Cell biology's interest. What makes particularly interesting is that there is so much that is not fully understood. A cell is a complex system with thousands of molecular components working together in a coordinated way to produce the phenomenon we call "life". During the 20th century these molecular components were identified (for example, see Human Genome Project), but research continues on the details of cellular processes like the control of cell division and cell differentiation. Disruption of the normal control of cell division can cause abnormal cell behavior such as rapid tumor cell growth. Cells have complex interactions with the surrounding environment. Whether it is the external world of a single celled organism or the other cells of a multicellular organism, a complex web of interactions is present. Study of the mechanisms by which cells respond appropriately to their environments is a major part of cell biology research and often such studies involve what is called signal transduction. For example, a hormone such as insulin interacting with the surface of a cell can result in the altered behavior of hundreds of molecular components inside the cells. This sort of complex and finely tuned cell response to an external signal is required for normal metabolism and to prevent metabolic disorders like Type II diabetes. Most of the cells of a multi-cellular organism have the same genetic material in every cell; yet, there may be hundreds of different types of cells that make up the organism's body each with its own distinctive shape, size, and function. In any case, all of these cells were developed from one special cell, a zygote. The study of how the many cell types develop during embryonic development (Developmental Biology) is a branch of Biology that is heavily dependent on the use of microscopy. Much of the control of cell differentiation is at the level of the control of gene transcription, the control of which mRNAs are made. Muscle cells make muscle proteins and nerve cells make brain proteins. Geneticists, molecular biologists and cell biologists are working to discover the details of how cells specialize to accomplish hundreds of functions from muscle contraction to memory storage.

Cell Biology/Cell types/Prokaryotes. Most of these prokaryotic cells are small, ranging from 1 to 10 microns with a diameter no greater than 1 micron. The major differences between Prokaryotic and Eukaryotic cells are that prokaryotes do not have a nucleus as a distinct organelle and rarely have any membrane bound organelles [mitochondria, chloroplasts, endoplasmic reticulum, golgi apparatus, a cytoskeleton of microtubules and microfilaments] (the only exception may be a bacterium discovered to have vacuoles). Both types contain DNA as genetic material, have a surrounding cell membrane, have ribosomes[70 s], accomplish similar functions, and are very diverse. For instance, there are over 200 types of cells in the human body, that vary greatly in size, shape, and function. Prokaryotes are cells without a distinct nucleus.They have genetic material but that material is not enclosed within a membrane. Prokaryotes include bacteria and cyanophytes. The genetic material is a single circular DNA strand and is located within the cytoplasm. Recombination happens through transfers of plasmids (short circles of DNA that pass from one bacterium to another). Prokaryoytes do not engulf solids, nor do they have centrioles or asters. Prokaryotes have a cell wall made up of peptidoglycan. In majority of prokaryotes, the genome consists of a circular chromosome whose structure includes fewer proteins that found in the linear chromosomes of eukaryotes. Their chromosome is located in the nucleoid, a region of cytoplasm that appears lighter than surrounding cytoplasm in electron micrographs. Also, a single chromosome have much smaller rings of separately replication DNA called plasmids. Cell Surface. Prokaryotic cell walls maintain cell shape, provide physical protection, and prevents the cell from bursting in a hypotonic environment. In hypertonic environment, most prokaryotes lose water and shrink away from their wall (plasmolyze). The cell walls of prokaryotes differ in molecular composition and construction from those of eukaryotes. The bacterial cell walls contain peptidoglycan, a network of modified-sugar polymers cross linked by short polypeptides. This molecular fabric encloses the entire bacterium and anchors other molecules that extend from its surface. Archaeal cell walls contain a variety of polysaccharides and proteins but lack peptidoglycan. Gram-positive bacteria have simpler walls with a relatively large amount of peptidoglycan. It has a thick cell wall that traps the crystal violet in the cytoplasm. The alcohol rinse does not remove the crystal violet which masks the added red safanin dye. Gram-negative bacteria have less peptidoglycan and are structurally more complex, with an outer membrane that contains lipopolysaccharides. It has a thinner layer of peptidoglycan, and it is located in a layer between the plasma membrane and an outer membrane. The crystal violet is easily rinsed from the cytoplasm, and the cell appears pink or red. The cell wall of many prokaryotes is covered by a capsule, a sticky layer of polysaccharide or protein. The capsule enables prokaryotes to adhere to their substrate or to other individuals in a colony. Some capsules protect against dehydration, and some shield pathogenic prokaryotes from attack by their host's immune system. Some prokaryotes stick to their substrate or to one another by means of hair like protein appendages called fimbriae. They are also known as attachment pili. Fimbriae are usually shorter extension of the plasma membrane. In uniform environment, flagellated prokaryotes move randomly, but in heterogeneous environment, many prokaryotes exhibit taxis, movement toward or away from a stimulus. For example, prokaryotes that exhibit chemotaxis change their movement pattern in response to chemicals. They move toward nutrients or oxygen (positive chemotaxis) or away from a toxic substance (negative chemotaxis). Reproduction and Adaptation. Prokaryotes reproduce quickly in a favorable environment. By binary fission, a single prokaryotic cell divid into 2 cells, which then divide into 4, 8, 16, and on. Under optimal conditions, many prokaryotes can divide every 1-3 hours. However the cells eventually exhaust their nutrient supply, poison themselves with metabolic wastes, face competition from other microorganisms, or are consumed by other organisms. The prokaryotes are small, they reproduces by binary fission, and they have short generation times. The ability of some prokaryotes to withstand harsh conditions also contributes to their success. Certain bacteria develop resistant cell called endospores when an essential nutrient is lacking. The original cell produces a copy of its chromosome and surrounds it with a tough wall, forming the endospore. Water is removed from the endospore, and its metabolism halt. The rest of the original cell then disintegrates, leaving the endospore behind. Most endospore are so durable that they can survive in boiling water. In less hostile environments, endospore can remain dormant but viable for centuries, able to rehydrate and resume metabolism when their environment improves. Due to their short generation times, prokaryotic populations can evolve substantially in short periods of time. The ability of prokaryotes to adapt rapidly to new conditions highlights the fact that although the structure of their cells is simpler than that of eukaryotic cells, prokaryotes are not "primitive" or "inferior" in an evolutionary sense. They are highly evolved, and their population have responded successfully to many different types of environmental challenges. Rapid reproduction and mutation In sexually reproducing species, the generation of a novel allele by a new mutation is rare at any particular gene. Instead, most of the genetic variation in sexual populations results from the way existing alleles are arranged in new combinations during meiosis and fertilization. Prokaryotes do not reproduce sexually, so at first glance their extensive genetic variation may seem puzzling. After repeated rounds of division, most of the offspring cells are genetically identical to the original parent cell; however owing to insertions, deletions, and base-pair substitutions in their DNA, some of the offspring cells may differ genetically. The new mutations, though individually rare, can greatly increase genetic diversity in specie that has short generation times and large population sizes. This diversity, in turn, can lead to rapid evolution: individuals that are genetically better equipped for their local environment tend to survive and reproduce more prolifically than less fit individuals. Transformation and Transduction. In transformation, the genotype and possible phenotype of a prokaryotic cell are altered by the uptake of foreign DNA from its surroundings. For example, bacteria from a harmless strain of Streptococcus pneumonia can be transformed to pneumonia-causing cells if they are placed into a medium containing dead, broken-open cells of the pathogenic strain. This transformation occurs when a live nonpathogenic cell takes up a piece of DNA carry the allele for pathogenicity. The foreign allele is then incorporated into the cell's chromosome, replacing the existing nonpathogenic allele- an exchange of homologous DNA segments. The cell is now a recombinant: Its chromosome contains DNA derived from two different cells. In transduction, bacteriophage carries bacterial genes from one hose cell to another; transduction is a type of horizontal gene transfer. For most phages, transduction results from accidents that occur during the phage reproductive cycle. A virus that carries bacterial DNA may not be able to reproduce because it lacks its own genetic material. However, the virus may be able to attach to another bacterium (a recipient) and inject the piece of bacterial DNA acquired from the first cell (the donor). Some of this DNA may subsequently replace the homologous region of the recipient cell's chromosome by DNA recombination. In such a case, the recipient cell's chromosome becomes a combination of NA derived from two cells; genetic recombination has occurred. Conjugation and Plasmids In a process called conjugation, genetic material is transferred between two bacterial cells ( of same or different species) that are temporarily joined. The DNA transfer is one way: One cell donates the DNA, and the other receives it. The donor uses sex pili to attach to the recipient. After contacting a recipient cell, each sex pilus retracts, pulling the two cells together, much like a grappling hook. A temporary "mating bridge" then forms between the two cells, providing an avenue for DNA transfer. In most cases, the ability to form sex pili and donate DNA during conjugation results from the presence of a particular piece of DNA called the F factor. The F factor consists about 25 genes, most required for the production of sex pili. The F factor can exist either as a plasmid or as a segment of DNA within the bacterial chromosome. The F factor in its plasmid form is called F plasmid. Cells containing the F plasmid, designated F+ cells, function as DNA donors during conjugation. Cells lacking the F factor, designated F-, function as DNA recipients during conjugation. The F+ condition is transferable in the sense that an F+ cell converts and F- cell to F+ is a copy of the entire F+ plasmid is transferred. Chromosomal genes can be transferred during conjugation when the donor cell's F factor is integrated into the chromosome. A cell with the F factor built into its chromosome is called an Hfr cell. Like an F+ cell, an Hfr cell functions as a donor during conjugation with an F- cell. When chromosomal DNA from an Hfr cell enters and F- cell, homologous regions of the HFr and F- chromosomes may align, allowing segments of their DNA to be exchanged. This results in the production of a recombinant bacterium that has genes derived from two different cells- a new genetic cariant on which evolution can act. Though these processes of horizontal gene transfer have so far been studied almost exclusively in bacteria, it is assumed that they are similarly important in archaea. Diverse nutritional and metabolic adaptations. The mechanisms discussed in the previous section- rapid reproduction, mutation, and genetic recombination- underlie that extensive genetic variation found in prokaryotic populations. This variation is reflected in the nutritional adaptations found in prokaryotes. Like all organisms, prokaryotes can be categorized by their nutrition; how they obtain every and the carbon used in building the organic molecules that make up cells. Nutritional diversity is greater among prokaryotes than among eukaryotes: Every type of nutrition observed in eukaryotes is represented among the prokaryotes, along with some nutritional modes unique to prokaryotes. Phototrophs are the organisms that obtain energy from light. Chemotrophs are the organisms that obtain energy from chemicals. Organisms that need only an inorganic compound are called autotrophs. Heterotrophs require at least one organic nutrient to make other organic compounds. Combining these possibilities for energy sources and carbon sources results in four major modes of nutrition. Photoautotrophs: photosynthetic organisms that capture light energy and use it to drive the synthesis of organic compounds and other inorganic carbon compounds. Cyanobacteria and many other groups of prokaryotes are photoautotrophs, as are plants and algae. Chemoautotrophs: also need only an inorganic compound; however, instead of using light as an energy source, they oxidize inorganic substance, such as hydrogen sulfide, ammonia, or ferrous ions. This mode of nutrition is unique to certain prokaryotes. Photoheterotrophs: Harness energy from light but must obtain carbon in organic form. This mode is unique to certain marine and halophilic (salt-loving) prokaryotes. Chemoheterotrphs: must consume organic molecules to obtain both energy and carbon. This nutritional mode is widespread among prokaryotes. Fungi, animals, most protists, and even some parasitic plants are also chemoheterotrophs. The Role of Oxygen In Metabolism. Prokaryotic metabolism also varies with respect to oxygen. Obligate aerobes use oxygen for cellular respiration and cannot grow without it. Obligate anaerobes, however, are poisoned by oxygen. Some obligate anaerobes live exclusively by fermentation; other extract chemical energy by anaerobic respiration, in which substance other than oxygen such as nitrate ions or sulfate ions accept electrons at the "downhill" end of electron transport chains. Facultative anaerobes use oxygen if it is present but can also carry out anaerobic respiration or fermentation in an anaerobic environment. Nitrogen Metabolism Nitrogen is essential for the production of amino acids and nucleic acids in all organisms. Whereas eukaryotes can obtain nitrogen from only a limited group of nitrogen compounds, prokaryotes can metabolize nitrogen in a wide variety of forms. For example, some cyanobacteria and some methanogens covert atmospheric nitrogen to ammonia, a process called nitrogen fixation. The cells can then incorporate this "fixed" nitrogen into amino acids and other organic molecules. In terms of their nutrition, nitrogen-fixing cyanobacteria are some of the most self-sufficient organisms, since they need only light, carbon dioxide, nitrogen, water and some minerals to grow. Nitrogen fixation by prokaryotes has a large impact on other organisms. For example, nitrogen -fixing prokaryotes can increase the nitrogen but can use the nitrogen compounds that the prokaryotes produce from ammonia. Metabolic Cooperation Cooperation between prokaryotes allows them to use environmental resource they could not use as individual cells. In some cases, this cooperation takes place between specialized cells of a colony. For instance, the cyanobacterium Anabaena has genes than encode proteins for photosynthesis and for nitrogen fixation, but a single cell cannot carry out both processes at the same time. The reason is that photosynthesis produces oxygen which inactivates the enzymes involved in nitrogen fixation. Instead of living as isolated cells, anabaena forms filamentous colonies synthesis while a few specialized cells called heterocytes carry out only nitrogen fixation. Each heterocyte is surrounded by a thickened cell wall that restricts entry of oxygen produced by neighboring photosynthetic cells. Intercellular connections allow heterocytes to transport fixed nitrogen to neighboring cells and to receive carbohydrates. Metabolic cooperation between different prokaryotic species often occurs in surface-coating colonies known as biofilms. Cells in a biofilm secrete signaling molecules that recruit nearby cells, causing the colonies to grow. The cells also produce proteins that stick the cells to the substrate and on to another. Channels in the biofilm allow nutrients to reach cells in the interior and wastes to be expelled. Biofilm damage industrial and medical equipment, contaminate products, and contribute to tooth decay and more serious health problems. In another example of cooperation between prokaryotes, sulfate-consuming bacteria coexist with methane-consuming archaea in ball- shaped aggregates on the ocean floor. The bacteria appear to use the archaea's waste products, such as organic compounds and hydrogen. In turn, the bacteria produce compounds that facilitate methane consumption by the archaea. This partnership has global ramifications. Reference. Berg, Jeremy M., John L. Tymoczko, and Lubert Stryer. Biochemistry. 7th ed. New York: W.H. Freeman, 2012. Print. Reece, Campbell, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minosky, and Robert B. Jackson. Biology. 8th ed. San Francisco: Cummings, 2010. Print. See also. Eukaryotes

Cell Biology/Cell types/Eukaryotes. Eukaryotes house a distinct nucleus, a structure in which the genetic material (DNA) is contained, surrounded by a membrane much like the outer cell membrane. Eukaryotic cells are found in most algae, protozoa, all multicellular organisms (plants and animals) including humans. The genetic material in the nucleus forms multiple chromosomes that are linear and complexed with proteins that help the DNA 'pack' and are involved in regulation of gene expression. The cells of higher plants differ from animal cells in that they have large vacuoles, a cell wall, chloroplasts, and a lack of lysosomes, centrioles, pseudopods, and flagella or cilia. Animal cells do not have the chloroplasts, and may or may not have cilia, pseudopods or flagella, depending on the type of cell. Comparing Prokaryotic and Eukaryotic Cells. All cells have several basic features in common: they are all bounded by a selective barrier, plasma membrane. Cytosol is a jellylike substance that is semifluid. All cells contain chromosomes which carry genes in the form of DNA, and ribosomes that make proteins according to instructions from the gene. The major difference between prokaryotic and eukaryotic cells is the location of their DNA. In eukaryotic cell, DNA is found at the nucleus, which is bounded by a double membrane. (the word eukaryotic is from the Greek eu, true, and karyon, kernel, here referring to the nucleus). Eukaryotic cells are much larger than prokaryotic cells; size is general aspect of cell structure that relates to function. The logistics of carrying out cellular metabolism sets limits on cell size. At the lower limit, the smallest cells, known are bacteria called mycoplasmas have diameters between 0.1 and 1.0mm. These are the smallest packages with enough DNA to program metabolism and enough enzymes and other cellular equipment to carry out the activities necessary for a cell to sustain itself and reproduce. Metabolic requirements also impose theoretical upper limits on the size that is practical for a single cell. Plasma membrane functions as a selective barrier that allows sufficient passage of oxygen, nutrients, and wastes to service the entire cell. For each square micrometer of membrane, only a limited amount of a particular substance can cross per second, so the ratio of surface area to volume is critical. As a cell increases in size, its volume grows proportionately more than its surface area. Area is proportional to a linear dimension squared, whereas volume is proportional to the linear dimension cubed. Therefore a smaller object has a greater ration of surface area to volume. The need for a surface area sufficiently large to accommodate the volume helps explain the microscopic size of most cells, and the narrow, elongated shapes of others, such as nerve cells. Larger organisms has more cells compare to smaller cells. High ratio of surface area to volume is especially important in cells that exchange a lot of material with their surroundings such as intestinal cells. Such cells may have many long, thin projections from their surface called microvilli, which increase surface area without an appreciable increase in volume. Animal Cells. Flagellum: locomotion organelle present in some animal cells; composed of a cluster of microtubules within an extension of the plasma membrane. Centrosome: region where the cell's microtubules are initiated contains a pair of centrioles which function is unknown. Cytoskeleton: reinforces cell's shape, functions in cell movement components are made of protein. It includes microfilaments, intermediate filaments, and microtubules. Microvilli: projections that increase the cell's surface area. Peroxisome: organelle with carious specialized metabolic functions; produces hydrogen peroxide as a by-product, then converts it to water. Mitochondrion: organelle where cellular respiration occurs and most ATP is generated. Lysosome: digestive organelle where macromolecules are hydrolyzed. Golgi apparatus: organelle active in synthesis, modification, sorting, and secretion of cell products. Ribosomes: complexes (small brown dots) that make proteins; free in cytosol or bound to rough ER or nuclear envelope. Plasma membrane: membrane enclosing the cell Endoplasmic Reticulum (ER): network of membraneous sacs and tube; active in membrane synthesis and other synthetic and metabolic processes; has rough (ribosome-studded) and smooth regions. (Rough ER, and Smooth ER) Nucleus: nucleus contains: "Nuclear envelope": double membrane enclosing the nucleus; perforated by pores; continuous with ER "Nucleolus": structure involved in production of ribosomes; a nucleus has one or more nucleoli "Chromatin": material consisting of DNA and proteins; visible as individual chromosomes in a dividing cell In animal cells, lysosomes, centrosomes with centrioles, and flagella are present but not in plant cells. Plant Cell. Cell Wall: outer layer that maintains cell's shape and protects cell from mechanical damage; made of cellulose, other polysaccharide, and protein. Plasmodesmata: channels through cell walls that connect the cytoplasms of adjacent cells. Chloroplast: photosynthetic organelle; converts energy of sunlight to chemical energy stored in sugar molecules. Central vacuole: prominent organelle in older plant cells; functions include storage, breakdown of waste products, hydrolysis of macromolecules; enlargement of vacuole is a major mechanism of plant growth. Nucleus: nucleus contains: "Nuclear envelope": double membrane enclosing the nucleus; perforated by pores; continuous with ER "Nucleolus": structure involved in production of ribosomes; a nucleus has one or more nucleoli "Chromatin": material consisting of DNA and proteins; visible as individual chromosomes in a dividing cell Golgi apparatus: organelle active in synthesis, modification, sorting, and secretion of cell products. Endoplasmic Reticulum (ER): network of membraneous sacs and tube; active in membrane synthesis and other synthetic and metabolic processes; has rough (ribosome-studded) and smooth regions. (Rough ER, and Smooth ER) Ribosomes: complexes (small brown dots) that make proteins; free in cytosol or bound to rough ER or nuclear envelope. Cytoskeleton: reinforces cell's shape, functions in cell movement components are made of protein. It includes microfilaments, intermediate filaments, and microtubules. In plant cell, chloroplasts, central vacuole, cell wall, and plasmodesmata are present but not in animal cells. Chromatin in the plant cell is a primary protein Nucleus. The nucleus contains most of the genes in the eukaryotic cell; some genes are located in mitochondria and chloroplast. It is generally the most conspicuous organelle in a eukaryotic cell. The nuclear envelope encloses the nucleus, sparating its contents from the cytoplasm. The nuclear envelope is a double membrane, each a lipid bilayer with associated proteins. The envelope is perforated by pore structure that are about 100nm in diameter. At the lip of each pore, the inner and outer membranes of the nuclear envelope are continuous. Pore complex lines each pore and regulates the entry and exit of most proteins and RNAs, as well as large complexes of macromolecules. Except at the pores, the nuclear side of the envelope is lined by the nuclear lamina, a netlike array of protein filaments that maintains the shape of the nucleus by mechanically supporting the nuclear envelope. Also nuclear matrix, a framework of fibers extending throughout the nuclear interior, present. Chromosomes are organized DNA units that carry the genetic information. Each chromosome is made up of material called chromatin, a complex of proteins and DNA. Stained chromatic usually appears as a diffuse mass, byt as a cell prepares to divide, the thin chromatin fibers coil up and condense thick enough to be distinguished as chromosomes. Each eukaryotic species has a characteristic number of chromosomes. For example human has 46 chromosomes. Nucleolus is a prominent structure within the nondividing nucleus. Ribosomal RNA (rRNA) is synthesized from instructions in the DNA; in nucleolus, proteins imported from the cytoplasm are assembled with rRNA into large and small ribosomal subunits. Theses subunits then exit the nucleus through the nuclear pores to the cytoplasm, where a large and a small subunit can assemble into a ribosome. the number depends on the species and the stage in the cell's reproductive cycle. The Nucleus directs protein synthesis by synthesizing messenger RNA (mRNA) according to instructions provided by the DNA. The mRNA is then transported to the cytoplasm via the nuclear pores. Once an mRNA molecule reaches the cytoplasm, ribosomes translate the mRNA's genetic message into the primary structure of a specific poly peptide. Ribosomes. Ribosomes are complexes made of ribosomal RNA and protein; ribosomes are the cellular components that carry out proteins synthesis, also known as protein factories. Cells that have high rates of protein synthesis have particularly large number of ribosomes. Cells active in protein synthesis also have prominent nucleoli. Ribosomes build proteins in two cytoplasmic locales. Free ribosomes are suspended in the cytosol, while bound ribosomes are attached to the outside of the endoplasmic reticulum or nuclear envelope. Bound and free ribosomes are structurally identical, and ribosomes can alternate between the two roles. Most of proteins are made on free ribosomes function within the cytosol. Bound ribosomes generally make proteins that are destined for insertion into membranes, for packaging within certain organelles such as lysosomes, or for export from the cell (secretion). The Endomembrane System. Endomembrane system carries out a variety of tasks in the cell. These tasks include synthesis of proteins and their transport into membranes and organelles or out of the cell, metabolism and movement of lipids, and detoxification of poisons. The membrane of this system are related either through direct physical continuity or by the transfer of membrane segments as tiny vesicles. The various membranes are not identical in structure and function; the thickness, molecular composition, and types of chemical reactions carried out in a given membrane are not fixed but modified several times during the membrane's life. The endomembrane system includes the nuclear envelope, the endoplasmic reticulum, the Golgi apparatus, lysosomes, various kinds of vacuoles, and the plasma membrane. Endoplasmic Reticulum (ER). Endoplasmic reticulum (ER) is an extensive network of membrane that it accounts for more than half the total membrane in many eukaryotic cells. The word endoplasmic means "within the cytoplasm", and reticulum is Latine for "little net". The ER consists of a network of membranous tubules and sacs called cisternae. The ER membrane separates the internal compartment of the ER, ER lumen (cavity) or cisternal space, from the cytosol. Since ER membrane is continuous with the nuclear envelope, the space between the two membranes of the envelope is continuous with the lumen of the ER. Smooth ER lacks ribosomes on its outer surface, and Rough ER has ribosomes on the outer surface of the membrane. Ribosomes are also attached to the cytoplasmic side of the nuclear envelope's outer membrane. Smooth ER- The smooth ER functions in diverse metabolic processes, which vary with cell type. These processes include synthesis of lipids, metabolism of carbohydrates, and detoxification of drugs and poisons. Enzymes of the smooth ER are important in the synthesis of lipids, including oils, phospholipids, and steroids. Sex hormones of vertebrates and the various steroid hormones are produced by the smooth ER in animal cells. Other enzymes of the smooth ER help detoxify drugs and poisons in liver cells. Detoxification involves adding hydroxyl groups to drug molecules, making them more soluble and easier to flush from the body. For example, sedative phenobarbital and other barbiturates are the drugs that metabolized in this manner by smooth ER in liver cells. Barbiturates, alcohol, and many other drugs induce the proliferation of smooth ER and its associated detoxification enzymes, therefore, increasing tolerance to the drugs; in other words, higher doses are required to achieve a particular effect. Also, because some of the detoxification enzymes have relatively broad action, the proliferation of smooth ER in response to one drug can increase tolerance to other drugs as well. The smooth ER also stores calcium ions; in muscle cells, a specialized smooth ER membrane pumps calcium ions from the cytosol into the ER lumen. When a muscle cell is stimulated by a nerve impulse, calcium ions rush back across the ER membrane into the cytosol and trigger contraction of the muscle cell. Rough ER- Many times of cells secrete proteins produced by ribosomes attached to rough ER. As a polypeptide chain grows from a bound ribosomes, it is threaded into the ER lumen through a pore formed by a protein complex in the ER membrane. As the new protein enters the ER lumen, it folds into its native shape. Most secretory proteins are glycoproteins, which have carbohydrates covalently bonded to them. After secretory proteins are formed, the ER membrane keeps them separate from proteins that are produced by free ribosomes and will remain in the cytosol. Secretory proteins depart from the ER wrapped in the membranes of vesicles that bud like bubbles from a specialized region called transitional ER. Transport vesicles are the vesicles in transit from one part of the cell to another. Rough ER is also a membrane factory for the cell; it grows in place by adding membrane proteins and phospholipids to its own membrane. As polypeptide destined to be membrane proteins grow from the ribosomes, they are inserted into the ER membrane and are anchored there by their hydrophobic portions. The rough ER makes its own membrane phospholipids; enzymes build into the ER membrane assemble phospholipids from precursors in the cytosol. The ER membrane expands and is transferred in the form of transport vesicles to other components of the endomembrane system. Golgi Apparatus. Golgi is a center of manufacturing, warehousing, sorting, and shipping. The products of the ER are modified and stored and then sent to other destinations. Golgi apparatus is extensive in cells specialized for secretion. The Golgi apparatus consists of flattened membranous sac, cisternae. The membrane of each cisterna in a stack separates ints internal space from the cytosol. Besicles concentrated in the vicinity of the Golgi apparatus are engaged in the transfer of material between parts of the Golgi and other structures. Golgi stack has a distinct structural polarity with the membrane of cisternae on opposite side of the stack different in thickness and molecular composition. The two poles of a Golgi stack are referred to as the cis face and the trans face; cis is the receiving and trans is shipping departments of the Golgi apparatus. The cis face is usually located near ER. Transport vesicles move material from the ER to the Golgi apparatus. A vesicle that buds from the ER can add its membrane and the contents of its lumen to the cis face by fusing with a Golgi membrane. The trans face give rise to vesicles, which pinch off and travel to other sites. The products of ER are usually modified during their transit from the cis region to the trans region of the Golgi. Various Golgi enzymes modify the carbohydrate portions of glycoproteins; carbohydrates are first added to proteins in the rough ER during the process of polypeptide synthesis. The carbohydrate on the resulting glycoprotein is then modified as it passes through the rest of the ER and the Golgi. The Golgi removes some sugar monomers and substitutes other, producing a large variety of carbohydrates. In addition, the Golgi apparatus manufactures certain macromolecules by itself. Many polysaccharides secreted by cells are Golgi products, including pectins and certain other non-cellulose polysaccharides made by plant cells and incorporated along with cellulose into their cell walls. Similar to secretory proteins, non-protein Golgi products will be secreted depart from the trans face of the Golgi inside transport vesicles that eventually fuse with the plasma membrane. The Golgi manufactures and refines its products in stages, with different cisternae containing unique teams of enzymes. Recent research has give rise to a new model of the Golgi as a more dynamic structure; According to the cisternal maturation model, the cisternae of the Golgi actually progress forward from the cis to the tras face of the Golgi, carrying and modifying their cargo as they move. Before a Golgi stack dispatches its products by budding vesicles fromt he trans face, it sorts these products and targets them for various parts of the cell. Molecular identification tags, such as phosphate groups added to the Golgi products, aid in sorting. Transport vesicles budded fromt he Golgi may have external molecules on their membranes that recognize "docking site" on the surface of specific organelles or on the plasma membrane, therefore, targeting the vesicle appropriately. Lysosomes. Lysosome is a membranous sac of hydrolytic enzymes that an animal cell uses to digest macromolecules. Lysosomal enzymes work best in the acidic environment found in lysosomes. If a lysosome breaks open or leaks its contents, the released enzymes are not very active because the cytosol has a neutral pH. However, excessive leakage from a large number of lysosomes can destroy a cell by autodigestion. Hydrolytic enzymes and lysosomal membrane are made by rough ER and then transferred to the Golgi apparatus for further processing. Proteins of the inner surface of the lysosomal membrane and the digestive enzymes are spared from destruction by having three dimensional shapes that protect vulnerable bonds from enzymatic attack. Phagocytosis is a process that amoebas and many other protists eat by engulfing smaller organisms or other food particles. The food vacuole formed , and then fuses with a lysosome and digests the food. Digestion products pass into cytosol and become nutrients for the cell. In human body, white blood cell helps defend the body by engulfing and destroying bacteria and other invaders. Lysosome use their hydrolytic enzymes to recycle the cell's own organic material; this is called autophagy. During autophagy, damaged organelle or small amount of cytosol become surrounded by a double membranes, and lysosome fuses with the outer membrane of their vesicle. The lysosomal enzymes dismantle the enclosed material, and the organic monomers are returned to the cytosol for reuse. The lysosomes become engorged with indigestible substrates, which begin to interfere with other cellular activities. Vacuoles. Vacuoles are membrane-bounded vesicles whose functions vary in different kinds of cells. Food vacuoles are formed by phagocytosis. Many freshwater protists have contractile vacuoles that pump excess water out of the cell, thereby maintaining a suitable concentration of ions and molecules inside the cell. In plants and fungi, which lacks lysosomes, vacuoles carry out hydrolysis; The central vacuole develops by the coalescence of smaller vacuoles, themselves derived from the endoplasmic reticulum and Golgi apparatus. The vacuolar membrane is selective in transportin solutes. As result, the solution inside the central vacuole is called cell sap, is different in composition from the cytosol. It can hold reserves of important organic compounds such as proteins stockpiled in the vacuoles of storage cells in seeds. Also it is the plant cell's main repository of inorganic ions, such as potassium and chloride. Many plant cells use their vacuoles contain pigments that color the cells. Vacuoles may also help protect the plant against predators by containing compounds that are poisonous or unpalatable to animals. The vacuole has a major role in the growth of plant cells, which enlarge as their vacuoles absorb water, enabling the cell to become larger with a minimal investment in new cytoplasm. Mitochondria and Chloroplasts. Mitochondria and chloroplasts are the organelles that convert energy to forms that cells can use for work. Mitochondria are the site of cellular respiration, the metabolic process that generates ATP by extracting energy from sugars, fats, and other fuels with the help of oxygen. Chloroplasts, are found in plants and algae, and they are the sites of photosynthesis. They convert solar energy to chemical energy by absorbing sunlight and using it to drive the synthesis of organic compounds such as sugar from carbon dioxide and water. Both of them are not part of endomembrane system. Mitochondria have two membrane separating their innermost space from the cytosol, and chloroplasts have three. The membrane proteins of mitochondria and chloroplasts are made not by ribosomes bound to the ER, but by free ribosomes in the cytosol and by ribosomes contained within these organelles themselves. They also contain small amount of DNA that programs the synthesis of the proteins made on the organelle's ribosomes. Mitochondria and chloroplasts are semiautonomous organelles that grow and reproduce within the cell. Mitochondria Mitochondria are found in all eukaryotic cells; Some cells have a single large mitochondrion, but more often a cell has hundreds or thousands of mitochondria. The number correlates with the cell's level of metabolic activity. The mitochondrion is enclosed by two membranes, each a phospholipid bilayer with a unique collection of embedded proteins. The outer membrane is smooth, but the inner membrane is convoluted, with infolding called cristae. The inner membrane divides the mitochondrion into two internal compartments : the first is the inter-membrane space, the narrow region between the inner and outer membranes and the second compartment, the mitochondrial matrix, is enclosed by the inner membrane. the matrix contains many different enzymes as well as the mitochondrial DNA and ribosomes. Enzymes in the matrix catalyze some steps of cellular respiration. Other proteins that function in respiration, including the enzyme that makes ATP are built into the inner membrane, As highly folded surface, the cristae give the inner mitochondrial membrane a large surface ares, thus enhancing the productivity of cellular respiration. Chloroplasts The chloroplast is a specialized member of related plant organelles called plastids. Chloroplasts contain the green pigment chlorophyll, along with enzymes and other molecules that function in the photosynthetic production of sugar. Its shape is lens-shaped and found in leaves. The contents of a chloroplast are partitioned from the cytosol by an envelope consisting of two membranes separated by a very narrow intermembrane space. Inside the chloroplast is another membranous system in the form of flattened, inter-connected sacs called thylakoids. Thylakoids are stacked like poker ships, and each stack is called granum. The fluid outside the thylakoids is the stroma which contains the chloroplast DNA and ribosomes as well as many enzymes. The membranes of the chloroplast divide the chloroplast space into three compartments: the intermembrane space, the stroma, and the thylakoid space. Cytoskeleton. Cytoskeleton is a network of fibers extending throughout the cytoplasm. It plays a major role in organizing the structure and activities of the cell. It is composed of three types of molecular structure: microtubules, microfilaments, and intermediate filaments. The main function of the cytoskeleton is to give mechanical support to the cell and maintain its shape. Cytoskeleton is stabilized by balance between opposing forces exerted by its elements. The cytoskeleton is more dynamic than an animal skeleton; it can be quickly dismantled in one part of the cell and reassembled in a new location, changing the shape of the cell. Also several types of cell motility involve the cytoskeleton. the cell motility encompasses both changes in cell location and more limited movements of parts of the cell. Cell motility require the interaction of the cytoskeleton with motor proteins. Cytoskeletal elements and motor proteins work together with plasma membrane molecules to allow whole cells to move along fibers outside the cell. The cytoskeleton is also involved in regulating biochemical activities in the cell in response to mechanical stimulation forces exerted by extracellular molecules via cell-surface proteins are apparently transmitted into the cell by cytoskeletal elements, and the forces may even reach the nucleus. Microtubules- thickest All eukaryotic cells have microtubules; the wall of the hollow tube is constructed from a globular protein called tubulin. Each tubulin protein is a dimer, a molecule made up of two subunits. A tubulin dimer consists of two slightly different polypeptides, alpha-tublin, and beta-tubulin. Microtubules grow in length by adding tubulin dimers. Due to the architecture of a microtubules, its two ends are slightly different; one end can accumulate or release tubulin dimers at a much higher rate than the other, therefore, growing and shrinking significantly during cellular activities. This is called the "plus end", not because it can only add tubulin proteins but because it's the end where both "on" and "off" rates are much higher. Microtubules shape and support the cell and also serve as tracks along which organelles equipped with other proteins can move. In animal cells, microtubules grow out from a centrosomes, a region that is often located near the nucleus and considered a "microtubule-organizing center". Theses microtubules function as compression-resisting girders of the cytoskeleton. Within the centrosome are a pair of centrioles, each composed of nine sets of triplet microtubules arrange in a ring. Before division, the centrioles replicate; although centrosomes with centrioles may help organize microtubule assembly in animal cell,s they are not essential for this function in all eukaryotes. Also specialized arrangement of microtubules is responsible for the beating of flagella and cilia. There are microtubule containing extensions that project from some cells. When cilia or flagella extend from cells that are held in place as part of a tissue layer, they can move fluid over the surface of the tissue. Flagella and cilia different in their beating patterns. A flagellum has an undulating motion that generates force in the same direction as the flagellum's axis. However cilia work more like oars, with alternating power and recovery strokes generating force in a direction perpendicular to the cilium's axis. A cillium may also act as a signal-receiving "antenna" for the cell. Cilia that have this function are nonmotile, and there is only one per cell. Membrane proteins on this kind of cilium transmit molecular signals from the cell's movement to its interior, triggering signaling pathways that may lead to changes in the cell's activities. Cillia-based signaling appears to be crucial to brain function and to embryonic development. Motile cilia and flagella share a common ultrastructure; each has a core of microtubules sheathed in an extension of the plasma membrane. Nine doublets of microtubules, the members of each parit sharing part of their walls, are arranged in a ring. This arrangement, referred to as the "9+2" pattern, is found in all eukaryotic flagella and motile cilia. Non-motile primary cilia have "9+0" pattern, lacking the central pari of microtubules. The microtubule assembly of a cilium or flagellum is anchored in the cell by a basal body, which is structurally very similar to a centriole. In flagella and motile cilia, flexible cross-linking proteins, evenly spaced along the length of the cilium or flagellum, connect the outer doublets to each other and to the two central microtubules Each outer doublet also has paris of protruding proteins spaced along its length and reaching toward the neighboring doublet; These are large motor proteins called dyneins, composed of several polypeptides. Dyneins are responsible for the bending movements of the organelle. A dynein molecule performs a complex cycle of movements cause by changes in these shape of the proteins, with ATP providing the energy for these changes. The mechanics of dynein-based bending involve a process that resembles walking. A typical dynein protein has two "feet" that "walk" along the microtubule of the adjacent doublet, one foot maintaining contact while the other releases and reattaches one step further along the microtubules. Without any restraints ont he movement of the microtubules doublets, one doublet would continue to "walk" along and slide past the surface of the other, elongating the cilium or flagellum rather than bending it. Microfillaments- thinnest Microfilaments are solid rods about 7nm in diameter. They are also called as actin filaments because they are build from molecules of actin, a globular protein. A microfilament si a twisted double chain of actin subunits. Microfilaments can form structural networks, due to the presence of proteins that bind along the side of an actin filament and allow a new filament to extend as a branch. The structure role of microfilaments in the cytoskeleton is to bear tension. A cortical microfilaments, a three-dimensional network formed by microfilaments just inside the plasma membrane, helps support the cell's shape. This network give the outer cytoplasmic layer of a cell called the cortex. In animal cells specialized for transporting materials across the plasma membrane, such as intestinal cells, bundles of microfilaments make up the core of microvilli. Microfillaments are well known for their role in cell motility, particularly as part of the contractile apparatus of muscle cells (myosin). Localized contraction brought about by actin and myosin also plays a role in amoeboid movement, which a cell such as an amoeba crawls along a surface by extending and flowing into cellular extension called pseudopodia. pseudopodia extend and contract through the reversible assembly of actin subunits nto microfilaments and of microfilaments into networks that convert cytoplasm fro a sol to a gel. The pseudopodium extends until the actin reassembles into a network. In plant cells, both actin-myosin interactions and sol-gel transformations brought about by actin may be involved in cytoplasmic streaming, a circular flow of cytoplasm within cells. intermediate filaments- middle range intermediate filaments are larger than the diameter of microfilaments but smaller than that of microtubules. Specialized for bearing tension (like microfilaments), intermediate filaments are a diverse class of cytoskeletal elements. Each type is constructed from a different molecular subunit such as keratins. Intermediate filaments are more permanent fixture of cells than are microfilaments and microtubules. Even after the death of the cell, intermediate filament networks often persist. Intermediate filaments are important in reinforcing the shape of a cell and fixing the position of certain organelles. For instance, the nucleus commonly sits within a cage made of intermediate filaments, fixed in location by braches of the filaments that extend into the cytoplasm. Other intermediate filaments make p the nuclear lamina that lines the interior of the nuclear envelope. In case where the shape of the entire cell is correlated with function, intermediate filaments support that shape. Cell Wall. Cell wall is an extracellular structure of plant cell that distinguishes them from animal cells. The wall protects the plant cell, maintains its shape, and prevents excessive uptake of water. The strong walls of specialized cells hold the plant up against the force of gravity. Plant cell walls are much thicker than the plasma membrane, and the exact chemical composition of the wall varies from species to species and even from one cell type to another in the same plant, but basic design of the wall is consistent. Microfibrils made of the polysaccharide cellulose are synthesized by an enzyme called cellulose synthase and secreted to the extracellular space, where they become embedded in a matrix of other polysaccharides and proteins. This combination of materials, strong fibers in a "ground substance" (matrix), is the same basic architectural design found in steel-reinforced concrete and in fiberglass. A young plant cell first secrets a thins and flexible wall called the primary cell wall; as the cell grows, the cellulose fibrils are oriented at right angles to the direction of cell expansion, possibly affecting the growth pattern. Between primary walls of adjacent cell is the middle lamella, which is a thin layer rich in sticky polysaccharides pectins. The middle lamella flues adjacent cells together. When the cell mature and stops growing, it strengthens its wall. Some plant cells do this simply by secreting hardening substances into the primary wall, but other cells add a secondary cell wall between the plasma membrane and the primary wall. Then secondary wall, often deposited in several laminated layer, has a strong and durable matrix that afford the cell protection and support. References. Berg, Jeremy M., John L. Tymoczko, and Lubert Stryer. Biochemistry. 7th ed. New York: W.H. Freeman, 2012. Print. Reece, Campbell, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minosky, and Robert B. Jackson. Biology. 8th ed. San Francisco: Cummings, 2010. Print. See also. Prokaryotes

Cell Biology/Membranes/Phospholipids. Phospholipids | Cholesterol » Phospholipids are amphipathic molecules that are made up of a hydrophilic head and a hydrophobic tail. The head group has a 'special' region that changes between various phospholipids. This head group will differ between cell membranes [types of cells] or different concentrations of specific 'head groups'. The fatty acid tails are also differ, but there is always one saturated and one unsaturated 'leg' of the tail. Phospholipids are 2 fatty acids one saturated and one unsaturated (shown by the double bond) that are linked to a glycerol. The Noncovalent Assemblies. For the phospholipid bilayer, even though it consists of hydrophilic heads on the outer membrane, the non-covalent hydrophobic tails of the inner membrane is the key to hold the entire membrane together because there are Van der Waals attractive forces within the cell membrane in which the hydrocarbon tails are closely packed together. With its non-covalent character inside the cell membrane, the hydrophobic molecules can easily pass through the cell membrane through passive diffusion. With this, the cell has control the molecules' movement through the transmembrane proteins complexes such as pores and gates. As for the hydrophilic molecules (such as ions, carbohydrates, proteins, amino acids, and nucleic acids), they require active diffusion in order to pass through the cell membrane because of their polarity and because they are hydrophilic (most non-covalent assemblies of the cell membrane are hydrophobic, such as hydrocarbon chains). The non-covalent assemblies of the cell membrane can help give rise to bubbles such as liposome, or lipid vesicle, that can deliver drugs into a specific part of the body. The structure of liposome is very similar to the cell membrane's lipid bilayer, and the materials that compose the liposome is identical to cell membrane. Because liposome is a bubble, the structure is shaped like a ring, where the hydrophilic heads are the outer and inner ring while the hydrophobic tails are in between the hydrophilic heads' rings. Because of the ring structure, the liposomes are able to trap aqueous materials such as drugs into their rings. Once the materials are within the ring, the liposomes would deliver them to a specific location in the body, such as cancer cells.

Cell Biology/Membranes/Cholesterol. « Phospholipids | Cholesterol | Semi-permeability and Osmosis » Cholesterol is a major component of cell membranes and serves many other functions as well. Cholesterol helps to 'pack' phospholipids in the membranes, thus giving more rigidity to the membranes. In colder conditions cholesterol also serves to keep the fluidity in the cell membrane, by keeping space in between the phospholipids. Also cholesterol serves diverse functions such as: it is converted to vitamin D (if irradiated with Ultra Violet light, modified to form steroid hormones, and is modified to bile acids to digest fats.

Cell Biology/Membranes/Semi-permeability and osmosis. « Cholesterol | Semi-permeability and Osmosis | Proteins and channels » The membranes of cells are a fluid, they are semi-permeable, which means some things can pass through the membrane through osmosis or diffusion. The rate of diffusion will vary depending on the its: size, polarity, charge and concentration on the inside of the membrane versus the concentration on the outside of the membrane. When something is permeable it means that something can spread throughout, like (The perfume is permeating the room.). Here is a list of some molecules and how they relate to passing through the membrane without assistance, in other words, through diffusion: Ions. Various substances will pass through the membranes at varying rates through diffusion.

Organic Chemistry/Overview of Functional Groups. Introduction. The number of known organic compounds is quite large. In fact, there are many times more organic compounds known than all the other (inorganic) compounds discovered so far, about 7 million organic compounds in total. Fortunately, organic chemicals consist of a relatively few similar parts, combined in different ways, that allow us to predict how a compound we have never seen before may react, by comparing how other molecules containing the same types of parts are known to react. These parts of organic molecules are called functional groups. The identification of functional groups and the ability to predict reactivity based on functional group properties is one of the cornerstones of organic chemistry. Functional groups are specific atoms, ions, or groups of atoms having consistent properties. A functional group makes up part of a larger molecule. For example, -OH, the hydroxyl group that characterizes alcohols, is an oxygen with a hydrogen attached. It could be found on any number of different molecules. Just as elements have distinctive properties, functional groups have characteristic chemistries. An -OH group on one molecule will tend to react similarly, although perhaps not identically, to an -OH on another molecule. Organic reactions usually take place at the functional group, so learning about the reactivities of functional groups will prepare you to understand many other things about organic chemistry. Memorizing Functional Groups. Don't assume that you can simply skim over the functional groups and move on. As you proceed through the text, the writing will be in terms of functional groups. It will be assumed that the student is familiar with most of the ones in the tables below. It's simply impossible to discuss chemistry without knowing the "lingo". It's like trying to learn French without first learning the meaning of some of the words. One of the easiest ways to learn functional groups is by making flash cards. Get a pack of index cards and write the name of the functional group on one side, and draw its chemical representation on the other. For now, a list of the most important ones you should know is provided here. Your initial set of cards should include, at the very least: Alkene, Alkyne, Alkyl halide (or Haloalkane), Alcohol, Aldehyde, Ketone, Carboxylic Acid, Acyl Chloride (or Acid Chloride), Ester, Ether, Amine, Sulfide, and Thiol. After you've learned all these, add a couple more cards and learn those. Then add a few more and learn those. Every functional group below is eventually discussed at one point or another in the book. But the above list will give you what you need to continue on. And don't just look at the cards. Say and write the names and draw the structures. To test yourself, try going through your cards and looking at the names and then drawing their structure on a sheet of paper. Then try going through and looking at the structures and naming them. Writing is a good technique to help you memorize, because it is more active than simply reading. Once you have the minimal list above memorized backwards and forwards, you're ready to move on. But don't stop learning the groups. If you choose to move on without learning the "lingo", then you're not going to understand the language of the chapters to come. Again, using the French analogy, it's like trying to ignore learning the vocabulary and then picking up a novel in French and expecting to be able to read it. Functional groups containing .... In organic chemistry functional groups are submolecular structural motifs, characterized by specific elemental composition and connectivity, that confer reactivity upon the molecule that contains them. Common functional groups include: "Note: The table above is adapted from the Functional Groups table on Wikipedia." Combining the names of functional groups with the names of the parent alkanes generates a powerful systematic nomenclature for naming organic compounds. The non-hydrogen atoms of functional groups are always associated with each by covalent bonds, as well as with the rest of the molecule. When the group of atoms is associated with the rest of the molecule primarily by ionic forces, the group is referred to more properly as a polyatomic ion or complex ion. And all of these are called radicals, by a meaning of the term "radical" that predates the free radical. The first carbon after the carbon that attaches to the functional group is called the alpha carbon. Alcohol containing two hydroxyl groups are called glycols. They have both common names and IUPAC names. Mnemonics for Functional Groups. These are possible mnemonics for the common functional groups. Vowels: Remember the vowels "A", "E", and "Y" for Alkane, Alkene, and Alkyne. Alkanes have only single covalent bonds. Alkenes have at least one double bond. Alkynes have at least one triple bond. The letters "I", "O", and "U" are not used. Furthermore, "O" and "U" would result in awkward pronunciations. Alcohol: Look for the "C-O-H" in "Alcohol." Ether: Ethers were anesthetics used in the 1800s. Dr. Kellogg also lived at the same time. Corn Flakes are made by Kellogg's. A rooster or cock (C-O-C) is the cornflake mascot. Or, think there is a C on "either" side of the O. Amine: Remember the "N" stands for nitrogen. Aldehyde: This sounds like "Adelaide," the Australian city. Australia is at the end of the Asian islands, and aldehydes are at the end of the hydrocarbon chain. The "Y" indicates a C=O double bond. Ketone: Imagine the diagonal strokes of "K" forming the C=O double bond. Carboxylic Acid: "Box" stands for boxed wine or C-O-H, alcohol. The "Y" indicates a C=O double bond. Ester: This sounds like "Estelle" George Costanza's mother in the TV show Seinfeld. George's nickname was Koko or Coco. So think of O=C-O-C. Amide: Amine with a "D". D for double.

Abstract Algebra. This book is on "abstract algebra" (abstract algebraic systems), an advanced set of topics related to algebra, including groups, rings, ideals, fields, and more. Readers of this book are expected to have read and understood the information presented in the Linear Algebra book, or an equivalent alternative. Pages in progress. Abstract Algebra/The hierarchy of rings Abstract Algebra/Rings, ideals, ring homomorphisms /Sources/

Japanese/Vocabulary/Everyday Phrases. see you Hesitation noises. Hesitation noises, or vocal pauses, are the "uh" and "um" of a language, filler sounds we produce when we pause to think while speaking. Using the correct hesitation noises can make the difference between natural sounding Japanese, and awkward foreign sounding speech. They are:

Japanese/Introduction. Japanese is spoken by 130 million people. This makes it the ninth most spoken language by native speakers. Linguists debate over the classification of the Japanese language, and one general theory asserts that Japanese is an isolated language and thus a language family of its own, known as Japonic languages. Another major theory includes Japanese as part of a hypothetical Altaic language family which spans most of Central Asia and would also include Turkic, Mongolic, Tungusic, and Korean languages. Neither of these theories has yet been generally accepted. Japan is the only country where Japanese is the sole official language (though the island of Angaur has Japanese as one of three official languages). There are, however, numerous speakers in other countries. These are largely due to emigration, most notably to the United States of America (California and Hawaii, in particular), Brazil and the Philippines. Furthermore, when Japan occupied and colonized much of East Asia, Southeast Asia, and the Pacific, the locals were educated in the Japanese language. Many elderly locals in Korea, Taiwan, and parts of China still speak Japanese. Japan has steadily developed for many centuries and, unlike many other cultures, has not been seriously affected by any major invasions until recent times. A substantial part of the vocabulary, though, has been borrowed over the years from Chinese, Portuguese, Dutch, German, French, and most recently English. Grammar. While Japanese grammar is very regular, it is markedly different from English. Japanese has been deemed a subject–object–verb (SOV) and topic-prominent language, whereas English is a subject–verb–object (SVO) and subject-prominent language. To illustrate, the English sentence “Cats eat mice” contains a subject (cats), a verb (eat), and an object (mice), in an SVO order, where the “-s” is a "plural marker", and “mouse” → “mice” is a plural marker by ablaut, but only the word order indicates which is the subject and the object—i.e. which is dining and which is the meal. The topic-prominence is not obvious in this example; “cat” is the subject (the agent) in English, but it is the topic (what the sentence is "about") in Japanese. In the above example, “は” is the topic, and “を” is the comment. The verb “kū” means “eat” in the sense of one animal consuming another. To speak about a person eating, it would make more sense to use the word “taberu” which means “eat,” as in to consume a meal. Japanese does not have articles (the words, “a” or “an”, or “the”), nor is it mandatory to indicate number (singular versus plural). In the sentence above, “” could mean either “cat” or “cats.” The “mouse/mice” ablaut does not occur in Japanese, which is an agglutinative language (inflecting by appending) and highly regular. In Japanese, the plural is formed by adding the ending “-tachi,” or “-ra.” Thus, the word, “cats” would be “nekotachi,” and is always plural, but the word “neko” can be either singular or plural. “Nekora,” however, would sound rather strange, as “-ra” and “-tachi” are not necessarily interchangeable. For the beginner, therefore, it is best not to worry about learning plural endings. For the English speaking student of Japanese grammar, the greatest hurdles to cross are probably the thought process of the Japanese sentence and learning the seemingly endless variety of endings available for modifying verbs and the order in which they can be strung together. The grammatical paradigm of SVO or SOV is completely irrelevant in the study of Japanese and other languages outside the Indo-European family of languages. In truth, it is not only unimportant, it is untrue, and will cause the student of the language to fail in acquiring fluency, because it is an artificial imposition of an Indo-European construct on a non-Indo-European language. Japanese, like Tagalog and many other languages, uses affixes to explicitly demonstrate grammatical relationships instead of using syntax. In Japanese, word order will not change the meaning of the sentence. However, it will change the emotional character. An SVO word order is not incorrect in Japanese, and native speakers use it frequently, as a matter of fact to heighten the emotional charge. Thus, “あれは何だ” is a simple question: “What is that?” But “何だあれは” should receive an exclamation point at the end because the word order indicates that the speaker is clearly upset or at least annoyed by whatever “that” is. Japanese sentences thus are not SOV. They are TV: T stands for topic and V for verb. Verbs are really the secret to success in acquiring fluency in Japanese. Thus, greatest attention should be given to learning the verb forms. There are two tenses of time: past and present. The present tense is used to describe future events. All past tense verbs have the ending “-た” (“-ta”) or “-だ” (“-da.”) The present tense always ends in the vowel “-u” in the positive and “-nai” in the negative. There is only one exception: the word, “だ” (“da”), which is the present tense of “be” (“am,” “are,” “is.”) As in probably all languages, this verb is highly irregular in Japanese and its usage must simply be memorized. For the English speaker the two time tenses should be quite easy to remember because in English the past tense is usually indicated by a final “-t” or “-d,” and the present tense of the basic positive present tense verb “do” ends in the “u” sound. The “-nai” ending sounds similar to “nay” in English. In conversational Japanese, a complete sentence will end in a present tense or past tense verb. As indicated earlier, there are many other possible endings, but they are not used in the final position to complete a sentence, nor are they used at the end of the active verb. Beyond the verb, there are words that indicate the function of words and phrases as they relate to the verb. The most important of these are “は” (“wa”), “が” (“ga”), “に” (“ni”), “の” (“no”), “を” (“o”), and “で” (“de.”) “は” marks what is being discussed. “が” follows the word that is the agent of the verb. This means who is doing something is the active tense, and who is receiving the action of a passive verb. In both cases, they mark “the who.” “に” indicates the direction toward and is usually translated as “in,” “to,” “at.” “の” indicates possession or source and usually is translated as “-’s” or “of.” “を” is only appropriate with active transitive verbs because it marks the direct object. Finally, “で” at the end of a place word indicates where a verb happened. It is usually translated “at,” “on,” or “in.” Added to the end of word that represents an object, it marks the instrument of the verb, what was used to perform the verb. It is translated, “with.” The example translates to "Speaking of cats, Pitchan came home and ate the dog’s food in the kitchen." (The “て” verb ending indicates incompletion.) Thus, every word or phrase in a Japanese sentence takes an ending that explicitly denotes the function of that word or phrase and how it relates to the verb. Levels of politeness. Japanese culture and society is based on a hierarchy of higher status (目上 "meue") and lower status (目下 "meshita"). As such, there are three varying levels of politeness. Because Japanese is primarily a "vertical" society, all relationships contain an element of relative station. For example, a student is a lower station than a teacher, and therefore a student would use polite language when speaking to a teacher, but the teacher would use plain language when speaking to a student. A salesperson talking to a customer would place themself far below the customer, and would therefore use honorific language, whereas the customer would use either plain or polite language. Honorific language is not a separate category from plain and polite language, but a separate concept that uses different rules. When using honorific language, a Japanese speaker modifies nouns, verbs, and adjectives to either lower themself and their associates, or exalt someone else and that individual's associates. Whereas the use of plain or polite language is determined by the relative station of the person "to" whom you are speaking, the use of honorific language is determined by the relative station of the person "about" whom you are speaking. Exalted language is applied when you are speaking about someone who is due respect, such as a professor, an executive, a political official, or a customer. Exalted language is only applied to other people, never to oneself. Humble language, however, is "only" applied to oneself and people associated with oneself. It would be inappropriate, for example, to use humble language to describe a beggar, even though they would be extremely low on the social ladder. The Japanese writing system. Japanese is written mostly using three writing scripts, "kanji", "hiragana" and "katakana". Kanji are Chinese characters that were first introduced to Japan in the 4th century. Unlike Chinese, Japanese is a highly inflected language with words changing their ending depending on case, number, etc. For this reason, the hiragana and katakana syllabaries were created. The hiragana serve largely to show the inflection of words, as conjunctions and such. The katakana are mainly used for loan-words from other languages. Kanji. The Japanese writing system is derived from the Chinese ideographic character set (Japanese: 漢字 "kanji", Mandarin: 汉字 "hanzi"). They are usually very similar to Traditional Chinese characters. Though kanji are Chinese in origin their use is dictated by Japanese grammar. Each character may be read in different ways depending on the context it is in. The number of existing Chinese characters has been variously estimated at between 40,000 and 80,000; however, only a small subset is commonly used in modern Japanese. An educated Japanese person will generally be able to read between 2,000 and 4,000 characters. In order to be literate in the Japanese language, the student should strive to master at least the 2,136 general-use characters (常用漢字 – "jōyō kanji") established by the Ministry of Education. Hiragana and katakana. The syllabaries, known as "kana" (), were developed around 900 AD by simplifying kanji to form the "hiragana" (ひらがな, or 平仮名) and the more angular "katakana" (カタカナ, or 片仮名). Hiragana can be recognized by the characteristic curved shapes, while katakana are identifiable by their sharp edges and straight lines. The creation of one of the scripts has been attributed to Kūkai (774-835, alias Kōbō Daishi) the famous monk who introduced Shingon Buddhism to Japan. Hiragana and katakana are almost completely phonetic—much more so than the English alphabet. Each set, however, is referred to as a "syllabary" rather than an alphabet because each character represents an entire syllable with only a single consonant (which is a more recent addition) (see ../Pronunciation/ for more). The syllabary charts in Japanese are referred to as the "gojūon" (), meaning "fifty sounds" because they are written in a five by ten chart. However, there are a few gaps in the table where certain sounds have fallen out of use. Modern Japanese can be written using 46 kana. In practical use, hiragana is used to write, for example, inflectional endings for adjectives and verbs (送り仮名 "okurigana"), grammatical particles (助詞 "joshi") and auxiliaries (助動詞 "jodōshi"), Japanese words that have no kanji (or not commonly known kanji), and annotations to kanji to indicate pronunciation (振り仮名 "furigana"). Katakana is used to write, for example, foreign words and names, onomatopoeia, emphasized words (somewhat like italicized words in English text), and technical and scientific words, such as plant, animal, and mineral names. Contents

CACS/Glossary/URI. Uniform Resource Identifier (URI) The URI is a phase that identifies any object on the internet by specifying the protocol, web address, file location, and name of the object. The URI may also contain data for delivery to the target server, such as a user id or query. A "URL" is one form of a URI. When accessing the Web, The URI is usually displayed in a special field in the "toolbar" of a "browser". URI originally stood for a "Universal Resource Identifier", and details are available from the "Internet Engineering Task Force" in RFC1630 at IETF Web site. The following regex may be used to validate strings for the RFC2396 specification: /^(https?|ftp):\/\/(?# protocol )(([a-z0-9$_\.\+!\*\'\(\),;\?&=-]|%[0-9a-f]{2})+(?# username )(:([a-z0-9$_\.\+!\*\'\(\),;\?&=-]|%[0-9a-f]{2})+)?(?# password )@)?(?# auth requires @ )((([a-z0-9][a-z0-9-]*[a-z0-9]\.)*(?# domain segments AND )[a-z]{2}[a-z0-9-]*[a-z0-9](?# top level domain OR )|(\d|[1-9]\d|1\d{2}|2[0-4][0-9]|25[0-5]\.){3}(?# )(\d|[1-9]\d|1\d{2}|2[0-4][0-9]|25[0-5])(?# IP address ))(:\d+)?(?# port ))(((\/+([a-z0-9$_\.\+!\*\'\(\),;:@&=-]|%[0-9a-f]{2})*)*(?# path )(\?([a-z0-9$_\.\+!\*\'\(\),;:@&=-]|%[0-9a-f]{2})*)(?# query string )?)?)?(?# path and query string optional )(#([a-z0-9$_\.\+!\*\'\(\),;:@&=-]|%[0-9a-f]{2})*)?(?# fragment )$/i

Japanese/Grammar/Verbs. Japanese verbs, (動詞; どうし), inflect heavily to indicate "formality", "tense" or "mood", primarily in their ending. There are two tenses, several levels of formality and three classes of verbs, depending on their inflection. The two tenses are perfective (often considered past tense) and present (or technically, non-past, as the future tense is not indicated). Out of the several levels of formality, two are the most common: plain and polite. Japanese verbs are officially categorised into five classes, but as two of these inflect much the same and another two only contain one verb each, these are usually merged into three when Japanese is taught as a foreign language. These are the "consonant stem"-, "vowel stem"- and "irregular" classes. Dictionaries use the plain present positive form (commonly known as "dictionary form") as the headword for verbs. Verbs are classed based on their conjugations. Their endings don't determine the class, but are a general indicator. Different inflections can also have suffixes. These may also be verbs with their own conjugations. Not all suffixes can be used on all verb inflections and others may only follow the verb stem. Examples are conjunctive + いる, せる・させる (causative), and られる (potential). Ignoring the formality and the negative conjugations, the following is a list of verb conjugations Ichidan class. Vowel-stem verbs end on a full syllable (hence the term: "vowel"-stem). In a sense, the final "る" of the dictionary form is dropped and the respective endings just added on. The Japanese term "" refers to the fact that the stem ending occupies only one row in the kana chart. The following table shows a few forms of the verb "食べる" (たべる, "e." to eat): Godan class. Consonant-stem verbs end in the middle of a syllable (hence the term; "consonant"-verb). That syllable changes depending on the form. The plain form has an "u" sound ("u", "tsu", "ru", "ku", "gu", "bu", "mu", "su"), the "-masu" form has an "i" sound ("i", "chi", "ri", "ki", "gi", "bi", "mi", "shi"), and the negative form has an "a" sound ("wa", "ta", "ra", "ka", "ga", "ba", "ma", "sa"). The potential form has an "e" sound ("e", "te", "re", "ke", "ge", "be", "me", "se") and the volitional form has an "ō" sound ("ō", "tō", "rō", "kō", "gō", "bō", "mō", "sō"), so putting these together with the sounds above shows that verb conjugations follow the vowel syllabary of the Japanese character set:　あ "a", い "i", う "u", え "e" and お "o". The Japanese term "" comes from the fact that the stem's last syllable spans all five rows of the kana chart in at least one form. The following table shows a few forms of the consonant-stem verb "話す" (はなす "e." to speak). The て-form (conjunctive) and past positive form of a consonant-stem verb change the root for euphony according to the last syllable of the root (example in parentheses): 行く (いく) (to go) has an exceptional て-form 行って (いって). If the verb stem ends on "う" such as in the verb 買う(かう, "e." to buy) then its negative stem becomes -わ as in 買わない ("to not buy"). This is because the root is treated as kawu (despite the "wu" syllable not existing in modern Japanese). Irregular verbs. Two common verbs do not share a conjugation pattern with any other verb. They are therefore commonly classed as "irregular" verbs. Formally, they are called "変格" (へんかく) verbs, as opposed to the regular "正格" (せいかく) verbs. This construction is made to use verbs and nouns of Chinese origin, for instance, from Chinese "確認"　("què rèn", confirmation) is formed in Japanese the verb "確認する" (かくにんする), or "約分" ("yuē fēn", simplify a fraction (math.)) which derives into "約分する"　(やくぶんする). The forms are "する" ("e." to do, as in the examples) and "" ("e." to come). The following table shows some of their conjugation forms. Many verbs end on "〜する" and can be grouped in three categories: The only commonly-used combination with "来る" is "やってくる", meaning "to come". Polite forms. The polite (or formal) forms are simple as all of the consonant-stem verbs sit in the い-line (行く→行き) and the inflections are the same for consonant- and vowel-stem verbs. The following table shows the polite forms for "行く" (いく, "e." to go): The imperative (〜ませ) is not used in formal forms except for a few polite verbs (see below). Other irregularities. A small number of verbs tend to be conjugated differently from the groups that they are normally placed in. Polite language. The verbs below are all consonant stem verbs but conjugate differently. While the regular forms also exist, they are seldom used. The conjunctive and past forms of the first two verbs, "くださる" and "なさる", also have the alternative forms "くだすって／くだすった" and "なすって／なすった", in addition to the normal regular conjugations "くださって／くださった" and "なさって／なさった". These alternative forms have, however, fallen into disuse. While they are often encountered when reading texts from a few decades ago, the regular conjugations are usually used today. The first three of the above verbs are also the only ones where the imperative form "ませ" of the auxiliary verb, "ます", is used to add an extra level of politeness: Additionally, ございます, which originally came from the now-defunct "yodan" (四段, "e." four-row) classical Japanese verb "ござる", is also used, although in modern usage, it is always used with the ます auxiliary verb ending. There is no imperative form (i.e. you cannot use ませ like above). 得る. 得る (うる/える, "e." to get, or to be able to) is the only surviving "nidan" (二段, "e." two-row) class verb in modern Japanese. It has conjugations as in the below table: "得る" can be read both as "える" in its "terminal form" (at the end of the sentence, or in situations such as attaching to べき). The "うる" reading is also used in those situations and in the "attributive form" (e.g. when attached to nouns). It is therefore incorrect to say "えるもの" as the correct form would be "うるもの". The combination "あり得る" is normally read "ありうる" in the present forms. All other conjugations follow the table above. Miscellaneous irregularities. The vowel stem verb "呉れる" (くれる "e." ) imperative form "くれ" (rather than the expected "くれろ"). Other "くれる" verbs of other unrelated meanings conjugate to the usual "くれろ". The consonant stem verb "ある" expresses existence, but absence is expressed with the adjective "ない". Note that many textbooks also treat "ない" as a verb. The reader may also wish to be aware that more formal "ぬ" negative form and its conjunctive form, "ず", are still used: "あらぬ"/"あらず". Summary of verb conjugations. See the Wikipedia page for present negative, past and past negative forms of "i" and "na" adjectives.

CACS/Glossary/ISOC. Internet Society (ISOC) The ISOC "(pronounced eye-sok)" is a cooperative of commercial, professional and governmental organizations that promotes internet technologies. It was founded in 1991 as a corporate umbrella for the "Internet Engineering Task Force (IETF)" and other ad-hoc activities ISOC now sponsors an annual conference and other events. It is headquartered in Virginia and Geneva, and its web address is www.isoc.org.

Esperanto/Authors. ^ Esperanto ^ | About the book: Authors The Esperanto textbook was started by . Other contributors have included: ^ Esperanto ^ | About the book: Authors

French/Lessons/Introductory/Review. G: The French alphabet. In addition, French uses several accents which are worth understanding. These are: à, è, ù, (grave accents) and é (acute accent). A circumflex applies to all vowels: â, ê, î, ô, û. A tréma (French for dieresis) is also applied: ä, ë, ï, ö, ü, ÿ. Two combined letters are used: æ and œ, and a cedilla is used on the c to make it sound like an English s: ç. V: Time. In French, “il est” is used to express the time; though it would literally translate as “he is”, it is actually, in this case, equivalent to “it is” (unpersonal "il"). Unlike in English, it is always important to use “heures” (“hours”) when referring to the time. In English, it is OK to say, “It’s nine,” but this wouldn’t make sense in French. The French time system traditionally uses a 24-hour scale. Shorthand for writing times in French follows the format "17h30", which would represent 5:30PM in English. V: The days of the week.. Notes: V: Seasons. "Bien..." is an adverb meaning "well". Its adjective equivalent is "bon(ne)", which means "good". Since "je vais", meaning "I go", uses an action verb,<br> the adverb "bien" is used. In English, I'm good, which uses the linking verb "am", is followed by an adjective rather than an adverb. "Est-ce que..." doesn't mean anything (like the Spanish upside down question mark) and is used to start a question.<br> This can be used in a similar manner to "do" in English. Instead of "You want it?", one can say "Do you want it?" "chez..." is a preposition meaning "at the house of...". "Chez moi" is used to say "at my place". "Chez ["name"]" is used to say "at ["name"'s] place". "on..." can mean "we" or "one".

Esperanto/Appendix/Alphabet and pronunciation. Alphabet. The Esperanto alphabet has 28 letters. Four letters from the English alphabet have been dropped – Q, W, X and Y – and there are six new accented letters: Ĉ, Ĝ, Ĥ, Ĵ, Ŝ and Ŭ. The first five have an angle-shape accent called a "circumflex" (^) over them, whilst the last has an accent rather like the bottom part of a circle, which is called a "breve" (˘). All of the accented letters are unique to Esperanto except for "ŭo" (Ŭ), which also exists in Belarusian, and "ĝo" (Ĝ), which also exists in Aleut. Some of the accented letters may be used in transcription systems for languages that use non-Latin alphabets. Vowels. As in English, five letters are vowels (A, E, I, O, U), and the rest are consonants. The letter "ŭo" (Ŭ) is a consonant, not a vowel. Collation. Collation in Esperanto is the same as for English, except that the accented characters are counted as separate characters and collated after their non-accented versions. Collation is as shown in the table above. Pronunciation. Each letter in Esperanto has only one pronunciation (allowing for cultural variation), and no letters are silent. There are six dipthongs (see the next section), but their pronunciation follows logically from their constituent letters, except for being shortened into a single syllable. This means that Esperanto is pronounced just as it is spelled. Also, each sound has only one way of being written, so it is very easy to spell Esperanto words you hear. The technical description for these traits is that Esperanto is "phonetic" and "orthographic". Stress. The stress on every word is put on the penultimate (second-to-last) syllable.

Esperanto/Introducing yourself. Be sure to make use of the pronunciation appendix. Grammar. Since Esperanto is a very regular language, all its rules can be applied universally without exceptions. This means Esperanto grammar concepts are much easier to understand than those of natural languages. In this first lesson, we shall examine how to form nouns, adjectives, and the present tense. Nouns. In any language, "nouns" are words that designate a person, place, thing, idea, or quality. Some examples of nouns in English are: "house", "friends", "cake", "John", "France", and "gardens". In Esperanto, all nouns end in -o. The part of the word that goes before the -o is known as the "root". For example, in the word urbo (city), urb- is the root and the -o makes it a noun. To make a noun plural, add a -j to the end, for example urboj (cities). Some examples of nouns in Esperanto: (human), (house), (friends), (cake), (John), (France) and (gardens). To say "a" or "an", as in "a town", just say the noun on its own, e.g. urbo (town, a town). There is no indefinite article ("a" or "an") in Esperanto. The word for "the" is la, e.g. la urbo (the city). La never changes for singular or plural. Adjectives. "Adjectives" are words that describe a noun. Some English examples are: "happy", "tired", "beautiful", "young" and "fresh". To change an Esperanto noun into its corresponding adjective, replace the -o with an -a. For example, urbo (town) gives rise to urba (urban, "relating to a town"). Some examples of adjectives in Esperanto: (happy), (tired), (beautiful), (young) and (fresh). In Esperanto, an adjective must "agree in number" with the noun it describes. This means that if the noun is singular, the adjective must also be. If the noun is plural, the adjective must also be, too. Some examples: la freŝa kuko (the fresh cake), la freŝaj kukoj (the fresh cakes); feliĉa homo (a happy person), feliĉaj homoj (happy people). The prefix mal- changes an Esperanto word into its opposite meaning – a feature that greatly reduces the vocabulary. Here are some examples of mal- words in Esperanto: (unhappy), (alert, not tired), (ugly), (old) and (stale). Adverbs. "Adverbs" are words that describe a verb, an adjective, or another adverb. They indicate manner, place, time or quantity. Some English examples are: "quickly", "orally", "at home", and "in writing". To change an Esperanto word into an adverb, replace the usual ending (-a for adjectives, -o for nouns, and -i for verbs) with -e. The meaning of the base word determines whether it becomes a manner, place, time or quantity adverb. Some examples of adverbs in Esperanto: (quickly), (orally), (at home), and (in writing). Please note that not all adverbs use this rule, but the overwhelming majority of them do. Once you are introduced to these adverbs, it will be obvious why there are exceptions. Personal pronouns. In Esperanto there are ten personal pronouns. However, you will initially need to only know seven of these pronouns. Possessive pronouns. To turn a personal pronoun into a possessive pronoun (which is an adjective), simply add an -a to the end. Verbs – present tense. The basic form of a verb is called its "infinitive". In English, this is the part of the verb that has "to" in front of it, as in the sentence "John likes to play football". In Esperanto, the infinitive simply has an -i after the root, e.g. (a game), (to play). The present tense has three forms in English. For example, one can say either "I kick", "I am kicking" or "I do kick"; "he laughs", "he is laughing", "he does laugh"; "Robert eats the cake", "Robert is eating the cake", "Robert does eat cake". All these forms are represented under one form in Esperanto. To form the present tense of any Esperanto verb, simply substitute the -i in the root with -as. Some examples: mi legas (I am reading), li ridas (He is laughing), Roberto manĝas la kukon (Robert eats the cake). You will also note that there is no verb conjugation in Esperanto for person. For example, in English you would say "Bob eats", "I eat", and "She eats"; In Esperanto, you would use the same form of the verb: "Bob manĝas", "Mi manĝas", "Ŝi manĝas". Objects and the accusative case. Like in English, every complete declarative sentence in Esperanto requires at least two parts: a subject and a verb. In the sentence "I ate", the subject is "I" and the verb is "ate". A subject is a noun which performs an action. However, in the sentence "I ate spaghetti", there is a third word: "spaghetti". The word "spaghetti" in this sentence is what is known as a direct object. A direct object is a noun which is having an action performed on it. It is being "verb'ed", so to speak. Take special note of the last sentence. In the first three sentences, the direct object directly followed the verb. However, in the last sentence, the word "Jane" directly follows the verb "gave". So why isn't Jane the direct object of the sentence? Because Jane is not having an action performed on her by the verb of the sentence, "give". Frank is not giving Jane, Frank is giving flowers "to Jane". Since the flowers are what is being given, the flowers are the direct object. So what is Jane in this sentence, then? Jane is what is known as an indirect object. An indirect object is a noun which is neither performing an action nor having an action performed directly upon it, but receiving the action of the verb less directly than the "direct object" (hence the name). In Esperanto, the indirect object will always take a preposition. For example, "Frank baked Jane a cake" becomes "Frank baked a cake for Jane." This basal reader stuff is real cute. But the simplicity quickly falls apart with more complex statements. Let's try some more advanced sentences in English. As you can see, English sometimes chokes on the complexities of real life. The incorrect understanding of the sentence about the First Amendment has the same basic structure as "The pilot makes the heading in the flight plan to the north.", giving the false parse a similar structure to "The amendment redirects the trust in their ability to criticize, into the Constitution.", which would mean "The First Amendment has persuaded the citizenry to trust that they are able to criticize the governor's administration of the presumptive draft on the grounds that the governor is administrating the presumptive draft unconstitutionally instead of trusting that they are able to criticize the governor's administration of the presumptive draft on other grounds.", which, depending on the minute details of history, the English language, and then-current law, could actually make sense, but is not the correct understanding of the grammar or the meaning of the sentence. English speakers can use their intuition to get past part of this problem, but in controversies, debates, and trials where words are deliberately or accidentally twisted, in technical fields, in natural language processing, and with English as a Foreign Language, it becomes increasingly difficult. Now you know one of the many reasons why natural language processing is an unsolved problem in computer programming. Another reason is that most English words have multiple meanings, up to 60 or even 100 meanings. Most Esperanto words only have one meaning, and its words with more than one meaning usually only have 2 or 3 meanings. Google Translate makes countless errors, and as such is no substitute for taking the courses over there at Lernu. We'll try that again by shoehorning it into Esperanto. These sentences are kind of stilted, and in another situation one would use a very different wording. The stilted wording more or less preserves the basic structure of the English sentences, though. We'll start with the translation of "Now let's try more advanced sentences in Esperanto.", which is "Nun ni provu iom Esperantajn frazojn kiuj estas pli progresintaj." In English, word order in a sentence helps determine whether a noun is a subject, a direct object, or an indirect object. In English, the order is often "subject, verb, direct object", "direct object, subject, verb" or "subject, verb, indirect object, direct object", and various other orders. As you can see from the table above, there are many plausible but incorrect comprehensions of the English sentences, but no plausible incorrect comprehensions of their Esperanto translations. That's because grammar in planned languages, such as Esperanto, tends to be much more precise than in natural languages. Esperanto uses affixes to explicitly and unambiguously mark words for part of speech, case, gender and number. Thus, part of speech tagging of Esperanto's single-stem words is already solved. In order to make a direct object in Esperanto, one simply adds the letter "n" to the noun (if the noun is plural, the "n" is added after the "j"). Therefore, in Esperanto, subjects, verbs, and direct objects can be put in any order, with little, if any, loss of clarity. All of the following sentences, which mean "the apple loves the banana" are grammatically correct in Esperanto. Conversation – Introducing yourself. Two people – Jean and Frank – meet for the first time:

Spanish/Sound Files. Audio Help

Spanish/Exercises/Regular Verbs. ^Lesson 3^ "Fill in the blanks". Por favor, rellena los espacios en blanco con la forma correcta del verbo: "Please, fill in the blanks with the correct form of the verb:" 1. Nosotros _________ (aprender) español. "We learn Spanish." 2. Yo _________ (comprar) un libro. "I buy a book." 3. Carmen y Roberto _________ (viajar) a Mexico. "Carmen and Roberto travel to Mexico." 4. Ana __________ (hablar) ingles. "Ana speaks English." 5. Tú ________ (beber) una cerveza. "You drink a beer." 6. Susana ________ (escribir) una carta. "Susana writes a letter." 7. Los niños _________ (estudiar) para el examen. "The children study for the exam." 8. Fernando y Lucas __________ (cantar) una cancion. "Fernando and Lucas sing a song." 9. Tú ________ (leer) un libro. "You read a book." 10. Vosotros _________ (subir) las escaleras. "You all (plural) climb the stairs." Soluciones a los ejercicios "Solution to exercices" ^Lesson 3^

Spanish/Solutions to Exercises. This page is a list of links to the solutions to the exercises in this Wikibook. The exercises themselves can be found here.

Ruby Programming. Ruby is an interpreted, object-oriented programming language. Its creator, , aka “Matz”, released it to the public in 1995. Its history is covered here. Its many features are listed here. The book is currently broken down into several sections and is intended to be read sequentially. Getting started will show how to install and get started with Ruby in your environment. Basic Ruby demonstrates the main features of the language syntax. The Ruby language section is organized like a reference to the language. Available modules covers some of the standard library. Intermediate Ruby covers a selection of slightly more advanced topics. Each section is designed to be self contained. Table of Contents. Ruby Semantic reference. See also some rdoc documentation on the various keywords. Built in Classes. This is a list of classes that are available to you by default in Ruby. They are pre-defined in “core.” Available Standard Library Modules. These are parts of Ruby that you have available (in the standard library, or via installation as a gem). To use them you typically have to require some filename, for example codice_62 would make accessible to you the Tracer class. You can see a list of basically all the (std lib ruby) modules available in the ruby source and lib readme. There are a several more modules available in the std lib, which are C based extensions. You can see their list here. Other Libraries. GUI Libraries. Here is info on some specifically: Intermediate Ruby. Here are some more in depth tutorials of certain aspects of Ruby.

Spanish/Exercises/Personal Pronouns. ^Lesson 1^ Pronombres personales. "(Personal pronouns.)" Ejercicio 1. Rellena los espacios en blanco con los pronombres personales correctos en español. "Exercise 1." "Fill the blank spaces with the correct Spanish personal pronouns." Ejercicio 2. Rellena los espacios en blanco con los pronombres personales correctos en español. "Exercise 2." "Fill the blank spaces with the correct Spanish personal pronouns." Soluciones a los ejercicios "Solution to exercices" ^Lesson 1^

Spanish/Exercises/Verbs ser And estar. ^Lesson 1^ Llena los espacios en blanco con la forma verbal correcta del verbo "ser". "Fill the blank spaces with the correct form of the verb "ser" (to be)." Llena los espacios en blanco con la forma verbal correcta del verbo "estar". "Fill the blank spaces with the correct form of the verb "estar" (to be)." Llena los espacios en blanco con la forma verbal correcta del verbo "ser" o "estar". "Fill the blank spaces with the correct form of the verb "ser" or "estar" (to be)." Soluciones a los ejercicios "Solution to exercices" ^Lesson 1^

CACS/Glossary/CSS. Cascading Style Sheet (CSS) is an HTML feature using a set of hierarchic input files that specify display characteristics used to interpret various "HTML" formatting tags. The CSS2 version also supports the description of display properties that are applied to "XML" applications. The CSS is an open specification maintained by the "W3C", and detailed online information describing style sheets may be found at the W3C's Specification Page.

GCSE Science/Electricity. Information on the Oxford, Cambridge and RSA examinations is available from the OCR Website. End of Module tests. See also Electronics.