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In 1901, the Federation of Australia was the process by which the six separate British self-governing colonies of New South Wales, Queensland, South Australia, Tasmania, Victoria and Western Australia formed one nation. They kept the systems of government that they had developed as separate colonies but also would have...
The last days of the Qing Dynasty were marked by civil unrest and foreign invasions. Responding to these civil failures and discontent, the Qing Imperial Court did attempt to reform the government in various ways, such as the decision to draft a constitution in 1906, the establishment of provincial legislatures in 1909...
In 1912, the Republic of China was established and Sun Yat-sen was inaugurated in Nanjing as the first Provisional President. But power in Beijing already had passed to Yuan Shikai, who had effective control of the Beiyang Army, the most powerful military force in China at the time. To prevent civil war and possible fo...
After the early 20th century revolutions, shifting alliances of China's regional warlords waged war for control of the Beijing government. Despite the fact that various warlords gained control of the government in Beijing during the warlord era, this did not constitute a new era of control or governance, because other ...
Four years into the 20th century saw the Russo-Japanese War with the Battle of Port Arthur establishing the Empire of Japan as a world power. The Russians were in constant pursuit of a warm water port on the Pacific Ocean, for their navy as well as for maritime trade. The Manchurian Campaign of the Russian Empire was f...
The Edwardian era in the United Kingdom is the period spanning the reign of King Edward VII up to the end of the First World War, including the years surrounding the sinking of the RMS Titanic. In the early years of the period, the Second Boer War in South Africa split the country into anti- and pro-war factions. The i...
The causes of World War I included many factors, including the conflicts and antagonisms of the four decades leading up to the war. The Triple Entente was the name given to the loose alignment between the United Kingdom, France, and Russia after the signing of the Anglo-Russian Entente in 1907. The alignment of the thr...
However, the crisis did not exist in a void; it came after a long series of diplomatic clashes between the Great Powers over European and colonial issues in the decade prior to 1914 which had left tensions high. The diplomatic clashes can be traced to changes in the balance of power in Europe since 1870. An example is ...
The First World War began in 1914 and lasted to the final Armistice in 1918. The Allied Powers, led by the British Empire, France, Russia until March 1918, Japan and the United States after 1917, defeated the Central Powers, led by the German Empire, Austro-Hungarian Empire and the Ottoman Empire. The war caused the di...
Much of the fighting in World War I took place along the Western Front, within a system of opposing manned trenches and fortifications (separated by a "No man's land") running from the North Sea to the border of Switzerland. On the Eastern Front, the vast eastern plains and limited rail network prevented a trench warfa...
Ultimately, World War I created a decisive break with the old world order that had emerged after the Napoleonic Wars, which was modified by the mid-19th century's nationalistic revolutions. The results of World War I would be important factors in the development of World War II approximately 20 years later. More immedi...
The Russian Revolution is the series of revolutions in Russia in 1917, which destroyed the Tsarist autocracy and led to the creation of the Soviet Union. Following the abdication of Nicholas II of Russia, the Russian Provisional Government was established. In October 1917, a red faction revolution occurred in which the...
Another action in 1917 that is of note was the armistice signed between Russia and the Central Powers at Brest-Litovsk. As a condition for peace, the treaty by the Central Powers conceded huge portions of the former Russian Empire to Imperial Germany and the Ottoman Empire, greatly upsetting nationalists and conservati...
The Russian Civil War was a multi-party war that occurred within the former Russian Empire after the Russian provisional government collapsed and the Soviets under the domination of the Bolshevik party assumed power, first in Petrograd (St. Petersburg) and then in other places. In the wake of the October Revolution, th...
The principal fighting occurred between the Bolshevik Red Army and the forces of the White Army. Many foreign armies warred against the Red Army, notably the Allied Forces, yet many volunteer foreigners fought in both sides of the Russian Civil War. Other nationalist and regional political groups also participated in t...
The May Fourth Movement helped to rekindle the then-fading cause of republican revolution. In 1917 Sun Yat-sen had become commander-in-chief of a rival military government in Guangzhou in collaboration with southern warlords. Sun's efforts to obtain aid from the Western democracies were ignored, however, and in 1920 he...
In North America, especially the first half of this period, people experienced considerable prosperity in the Roaring Twenties. The social and societal upheaval known as the Roaring Twenties began in North America and spread to Europe in the aftermath of World War I. The Roaring Twenties, often called "The Jazz Age", s...
Europe spent these years rebuilding and coming to terms with the vast human cost of the conflict. The economy of the United States became increasingly intertwined with that of Europe. In Germany, the Weimar Republic gave way to episodes of political and economic turmoil, which culminated with the German hyperinflation ...
Worldwide prosperity changed dramatically with the onset of the Great Depression in 1929. The Wall Street Crash of 1929 served to punctuate the end of the previous era, as The Great Depression set in. The Great Depression was a worldwide economic downturn starting in most places in 1929 and ending at different times in...
The depression had devastating effects in virtually every country, rich or poor. International trade plunged by half to two-thirds, as did personal income, tax revenue, prices and profits. Cities all around the world were hit hard, especially those dependent on heavy industry. Construction was virtually halted in many ...
The Great Depression ended at different times in different countries with the effect lasting into the next era. America's Great Depression ended in 1941 with America's entry into World War II. The majority of countries set up relief programs, and most underwent some sort of political upheaval, pushing them to the left ...
The interwar period was also marked by a radical change in the international order, away from the balance of power that had dominated pre–World War I Europe. One main institution that was meant to bring stability was the League of Nations, which was created after the First World War with the intention of maintaining wo...
A series of international crises strained the League to its limits, the earliest being the invasion of Manchuria by Japan and the Abyssinian crisis of 1935/36 in which Italy invaded Abyssinia, one of the only free African nations at that time. The League tried to enforce economic sanctions upon Italy, but to no avail. ...
Few Chinese had any illusions about Japanese designs on China. Hungry for raw materials and pressed by a growing population, Japan initiated the seizure of Manchuria in September 1931 and established ex-Qing emperor Puyi as head of the puppet state of Manchukuo in 1932. During the Sino-Japanese War (1937–1945), the los...
The Second Sino-Japanese War had seen tensions rise between Imperial Japan and the United States; events such as the Panay incident and the Nanking Massacre turned American public opinion against Japan. With the occupation of French Indochina in the years of 1940–41, and with the continuing war in China, the United Sta...
On December 7, 1941, Japan attacked the United States at Pearl Harbor, bringing it too into the war on the Allied side. China also joined the Allies, as eventually did most of the rest of the world. China was in turmoil at the time, and attacked Japanese armies through guerilla-type warfare. By the beginning of 1942, t...
It is possible that around 62 million people died in the war; estimates vary greatly. About 60% of all casualties were civilians, who died as a result of disease, starvation, genocide (in particular, the Holocaust), and aerial bombing. The former Soviet Union and China suffered the most casualties. Estimates place deat...
The Holocaust (which roughly means "burnt whole") was the deliberate and systematic murder of millions of Jews and other "unwanted" during World War II by the Nazi regime in Germany. Several differing views exist regarding whether it was intended to occur from the war's beginning, or if the plans for it came about late...
After World War II, Europe was informally split into Western and Soviet spheres of influence. Western Europe later aligned as the North Atlantic Treaty Organization (NATO) and Eastern Europe as the Warsaw Pact. There was a shift in power from Western Europe and the British Empire to the two new superpowers, the United ...
Over the course of the 20th century, the world's per-capita gross domestic product grew by a factor of five, much more than all earlier centuries combined (including the 19th with its Industrial Revolution). Many economists make the case that this understates the magnitude of growth, as many of the goods and services c...
Still, advancing technology and medicine has had a great impact even in the Global South. Large-scale industry and more centralized media made brutal dictatorships possible on an unprecedented scale in the middle of the century, leading to wars that were also unprecedented. However, the increased communications contrib...
The Soviet Union created the Eastern Bloc of countries that it occupied, annexing some as Soviet Socialist Republics and maintaining others as satellite states that would later form the Warsaw Pact. The United States and various western European countries began a policy of "containment" of communism and forged myriad a...
The Cold War saw periods of both heightened tension and relative calm. International crises arose, such as the Berlin Blockade (1948–1949), the Korean War (1950–1953), the Berlin Crisis of 1961, the Vietnam War (1959–1975), the Cuban Missile Crisis (1962), the Soviet war in Afghanistan (1979–1989) and NATO exercises in...
The Cold War drew to a close in the late 1980s and the early 1990s. The United States under President Ronald Reagan increased diplomatic, military, and economic pressure on the Soviet Union, which was already suffering from severe economic stagnation. In the second half of the 1980s, newly appointed Soviet leader Mikha...
In Latin America in the 1970s, leftists acquired a significant political influence which prompted the right-wing, ecclesiastical authorities and a large portion of the individual country's upper class to support coup d'états to avoid what they perceived as a communist threat. This was further fueled by Cuban and United...
The Space Age is a period encompassing the activities related to the Space Race, space exploration, space technology, and the cultural developments influenced by these events. The Space Age began with the development of several technologies that culminated with the launch of Sputnik 1 by the Soviet Union. This was the ...
The phrase "51st state" can be used in a positive sense, meaning that a region or territory is so aligned, supportive, and conducive with the United States, that it is like a U.S. state. It can also be used in a pejorative sense, meaning an area or region is perceived to be under excessive American cultural or military...
Under Article IV, Section Three of the United States Constitution, which outlines the relationship among the states, Congress has the power to admit new states to the union. The states are required to give "full faith and credit" to the acts of each other's legislatures and courts, which is generally held to include th...
Puerto Rico has been discussed as a potential 51st state of the United States. In a 2012 status referendum a majority of voters, 54%, expressed dissatisfaction with the current political relationship. In a separate question, 61% of voters supported statehood (excluding the 26% of voters who left this question blank). O...
Since 1898, Puerto Rico has had limited representation in the Congress in the form of a Resident Commissioner, a nonvoting delegate. The 110th Congress returned the Commissioner's power to vote in the Committee of the Whole, but not on matters where the vote would represent a decisive participation. Puerto Rico has ele...
Residents of Puerto Rico pay U.S. federal taxes: import/export taxes, federal commodity taxes, social security taxes, therefore contributing to the American Government. Most Puerto Rico residents do not pay federal income tax but do pay federal payroll taxes (Social Security and Medicare). However, federal employees, t...
Puerto Rico has been under U.S. sovereignty for over a century when it was ceded to the U.S. by Spain following the end of the Spanish–American War, and Puerto Ricans have been U.S. citizens since 1917. The island's ultimate status has not been determined as of 2012[update], its residents do not have voting representat...
This constitution was created when the U.S. Congress directed local government to organize a constitutional convention to write the Puerto Rico Constitution in 1951. The acceptance of that constitution by Puerto Rico's electorate, the U.S. Congress, and the U.S. president occurred in 1952. In addition, the rights, priv...
Puerto Rico is designated in its constitution as the "Commonwealth of Puerto Rico". The Constitution of Puerto Rico which became effective in 1952 adopted the name of Estado Libre Asociado (literally translated as "Free Associated State"), officially translated into English as Commonwealth, for its body politic. The is...
In November 2012, a referendum resulted in 54 percent of respondents voting to reject the current status under the territorial clause of the U.S. Constitution, while a second question resulted in 61 percent of voters identifying statehood as the preferred alternative to the current territorial status. The 2012 referend...
The Washington Post, The New York Times and the Boston Herald have published opinion pieces expressing support for the statehood of Puerto Rico. On November 8, 2012, Washington, D.C. newspaper The Hill published an article saying that Congress will likely ignore the results of the referendum due to the circumstances be...
Several days after the referendum, the Resident Commissioner Pedro Pierluisi, Governor Luis Fortuño, and Governor-elect Alejandro García Padilla wrote separate letters to the President of the United States Barack Obama addressing the results of the voting. Pierluisi urged Obama to begin legislation in favor of the stat...
On May 15, 2013, Resident Commissioner Pierluisi introduced H.R. 2000 to Congress to "set forth the process for Puerto Rico to be admitted as a state of the Union," asking for Congress to vote on ratifying Puerto Rico as the 51st state. On February 12, 2014, Senator Martin Heinrich introduced a bill in the US Senate. T...
Washington, D.C. is often mentioned as a candidate for statehood. In Federalist No. 43 of The Federalist Papers, James Madison considered the implications of the definition of the "seat of government" found in the United States Constitution. Although he noted potential conflicts of interest, and the need for a "municip...
Washington, D.C. residents who support the statehood movement sometimes use a shortened version of the Revolutionary War protest motto "No taxation without representation", omitting the initial "No", denoting their lack of Congressional representation; the phrase is now printed on newly issued Washington, D.C. license ...
This position was carried by the D.C. Statehood Party, a political party; it has since merged with the local Green Party affiliate to form the D.C. Statehood Green Party. The nearest this movement ever came to success was in 1978, when Congress passed the District of Columbia Voting Rights Amendment. Two years later in...
Other less likely contenders are Guam and the United States Virgin Islands, both of which are unincorporated organized territories of the United States. Also, the Northern Mariana Islands and American Samoa, an unorganized, unincorporated territory, could both attempt to gain statehood. Some proposals call for the Virg...
The Philippines has had small grassroots movements for U.S. statehood. Originally part of the platform of the Progressive Party, then known as the Federalista Party, the party dropped it in 1907, which coincided with the name change. As recently as 2004, the concept of the Philippines becoming a U.S. state has been par...
In Canada, "the 51st state" is a phrase generally used in such a way as to imply that if a certain political course is taken, Canada's destiny will be as little more than a part of the United States. Examples include the Canada-United States Free Trade Agreement in 1988, the debate over the creation of a common defense...
The phrase is usually used in local political debates, in polemic writing or in private conversations. It is rarely used by politicians themselves in a public context, although at certain times in Canadian history political parties have used other similarly loaded imagery. In the 1988 federal election, the Liberals ass...
The implication has historical basis and dates to the breakup of British America during the American Revolution. The colonies that had confederated to form the United States invaded Canada (at the time a term referring specifically to the modern-day provinces of Quebec and Ontario, which had only been in British hands ...
In the late 1940s, during the last days of the Dominion of Newfoundland (at the time a dominion-dependency in the Commonwealth and independent of Canada), there was mainstream support, although not majority, for Newfoundland to form an economic union with the United States, thanks to the efforts of the Economic Union P...
In the United States, the term "the 51st state" when applied to Canada can serve to highlight the similarities and close relationship between the United States and Canada. Sometimes the term is used disparagingly, intended to deride Canada as an unimportant neighbor. In the Quebec general election, 1989, the political ...
Due to geographical proximity of the Central American countries to the U.S. which has powerful military, economic, and political influences, there were several movements and proposals by the United States during the 19th and 20th centuries to annex some or all of the Central American republics (Costa Rica, El Salvador,...
Cuba, like many Spanish territories, wanted to break free from Spain. A pro-independence movement in Cuba was supported by the U.S., and Cuban guerrilla leaders wanted annexation to the United States, but Cuban revolutionary leader José Martí called for Cuban nationhood. When the U.S. battleship Maine sank in Havana Ha...
Several websites assert that Israel is the 51st state due to the annual funding and defense support it receives from the United States. An example of this concept can be found in 2003 when Martine Rothblatt published a book called Two Stars for Peace that argued for the addition of Israel and the Palestinian territorie...
In Article 3 of the Treaty of San Francisco between the Allied Powers and Japan, which came into force in April 1952, the U.S. put the outlying islands of the Ryukyus, including the island of Okinawa—home to over 1 million Okinawans related to the Japanese—and the Bonin Islands, the Volcano Islands, and Iwo Jima into U...
In 2010 there was an attempt to register a 51st State Party with the New Zealand Electoral Commission. The party advocates New Zealand becoming the 51st state of the United States of America. The party's secretary is Paulus Telfer, a former Christchurch mayoral candidate. On February 5, 2010, the party applied to regis...
Albania has often been called the 51st state for its perceived strongly pro-American positions, mainly because of the United States' policies towards it. In reference to President George W. Bush's 2007 European tour, Edi Rama, Tirana's mayor and leader of the opposition Socialists, said: "Albania is for sure the most p...
During World War II, when Denmark was occupied by Nazi Germany, the United States briefly controlled Greenland for battlefields and protection. In 1946, the United States offered to buy Greenland from Denmark for $100 million ($1.2 billion today) but Denmark refused to sell it. Several politicians and others have in re...
Poland has historically been staunchly pro-American, dating back to General Tadeusz Kościuszko and Casimir Pulaski's involvement in the American Revolution. This pro-American stance was reinforced following favorable American intervention in World War I (leading to the creation of an independent Poland) and the Cold Wa...
The Party of Reconstruction in Sicily, which claimed 40,000 members in 1944, campaigned for Sicily to be admitted as a U.S. state. This party was one of several Sicilian separatist movements active after the downfall of Italian Fascism. Sicilians felt neglected or underrepresented by the Italian government after the an...
There are four categories of terra nullius, land that is unclaimed by any state: the small unclaimed territory of Bir Tawil between Egypt and Sudan, Antarctica, the oceans, and celestial bodies such as the Moon or Mars. In the last three of these, international treaties (the Antarctic Treaty, the United Nations Convent...
An antenna (plural antennae or antennas), or aerial, is an electrical device which converts electric power into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver. In transmission, a radio transmitter supplies an electric current oscillating at radio frequency (i.e. a high freque...
Typically an antenna consists of an arrangement of metallic conductors (elements), electrically connected (often through a transmission line) to the receiver or transmitter. An oscillating current of electrons forced through the antenna by a transmitter will create an oscillating magnetic field around the antenna eleme...
The words antenna (plural: antennas in US English, although both "antennas" and "antennae" are used in International English) and aerial are used interchangeably. Occasionally the term "aerial" is used to mean a wire antenna. However, note the important international technical journal, the IEEE Transactions on Antennas...
The origin of the word antenna relative to wireless apparatus is attributed to Italian radio pioneer Guglielmo Marconi. In the summer of 1895, Marconi began testing his wireless system outdoors on his father's estate near Bologna and soon began to experiment with long wire "aerials". Marconi discovered that by raising ...
Antennas are required by any radio receiver or transmitter to couple its electrical connection to the electromagnetic field. Radio waves are electromagnetic waves which carry signals through the air (or through space) at the speed of light with almost no transmission loss. Radio transmitters and receivers are used to c...
One example of omnidirectional antennas is the very common vertical antenna or whip antenna consisting of a metal rod (often, but not always, a quarter of a wavelength long). A dipole antenna is similar but consists of two such conductors extending in opposite directions, with a total length that is often, but not alwa...
Both the vertical and dipole antennas are simple in construction and relatively inexpensive. The dipole antenna, which is the basis for most antenna designs, is a balanced component, with equal but opposite voltages and currents applied at its two terminals through a balanced transmission line (or to a coaxial transmis...
Antennas more complex than the dipole or vertical designs are usually intended to increase the directivity and consequently the gain of the antenna. This can be accomplished in many different ways leading to a plethora of antenna designs. The vast majority of designs are fed with a balanced line (unlike a monopole ante...
For instance, a phased array consists of two or more simple antennas which are connected together through an electrical network. This often involves a number of parallel dipole antennas with a certain spacing. Depending on the relative phase introduced by the network, the same combination of dipole antennas can operate...
However a log-periodic dipole array consists of a number of dipole elements of different lengths in order to obtain a somewhat directional antenna having an extremely wide bandwidth: these are frequently used for television reception in fringe areas. The dipole antennas composing it are all considered "active elements"...
At low frequencies (such as AM broadcast), arrays of vertical towers are used to achieve directionality and they will occupy large areas of land. For reception, a long Beverage antenna can have significant directivity. For non directional portable use, a short vertical antenna or small loop antenna works well, with the...
An antenna lead-in is the transmission line (or feed line) which connects the antenna to a transmitter or receiver. The antenna feed may refer to all components connecting the antenna to the transmitter or receiver, such as an impedance matching network in addition to the transmission line. In a so-called aperture ante...
Monopole antennas consist of a single radiating element such as a metal rod, often mounted over a conducting surface, a ground plane. One side of the feedline from the receiver or transmitter is connected to the rod, and the other side to the ground plane, which may be the Earth. The most common form is the quarter-wav...
The most widely used class of antenna, a dipole antenna consists of two symmetrical radiators such as metal rods or wires, with one side of the balanced feedline from the transmitter or receiver attached to each. A horizontal dipole radiates in two lobes perpendicular to the antenna's axis. A half-wave dipole the most ...
A necessary condition for the aforementioned reciprocity property is that the materials in the antenna and transmission medium are linear and reciprocal. Reciprocal (or bilateral) means that the material has the same response to an electric current or magnetic field in one direction, as it has to the field or current i...
Antennas are characterized by a number of performance measures which a user would be concerned with in selecting or designing an antenna for a particular application. Chief among these relate to the directional characteristics (as depicted in the antenna's radiation pattern) and the resulting gain. Even in omnidirectio...
Resonant antennas are expected to be used around a particular resonant frequency; an antenna must therefore be built or ordered to match the frequency range of the intended application. A particular antenna design will present a particular feedpoint impedance. While this may affect the choice of an antenna, an antenna'...
An antenna transmits and receives radio waves with a particular polarization which can be reoriented by tilting the axis of the antenna in many (but not all) cases. The physical size of an antenna is often a practical issue, particularly at lower frequencies (longer wavelengths). Highly directional antennas need to be ...
The majority of antenna designs are based on the resonance principle. This relies on the behaviour of moving electrons, which reflect off surfaces where the dielectric constant changes, in a fashion similar to the way light reflects when optical properties change. In these designs, the reflective surface is created by ...
The radio signal's electrical component induces a voltage in the conductor. This causes an electrical current to begin flowing in the direction of the signal's instantaneous field. When the resulting current reaches the end of the conductor, it reflects, which is equivalent to a 180 degree change in phase. If the condu...
The ordinary half-wave dipole is probably the most widely used antenna design. This consists of two 1⁄4-wavelength elements arranged end-to-end, and lying along essentially the same axis (or collinear), each feeding one side of a two-conductor transmission wire. The physical arrangement of the two elements places them ...
The standing wave forms with this desired pattern at the design frequency, f0, and antennas are normally designed to be this size. However, feeding that element with 3f0 (whose wavelength is 1⁄3 that of f0) will also lead to a standing wave pattern. Thus, an antenna element is also resonant when its length is 3⁄4 of a ...
The quarter-wave elements imitate a series-resonant electrical element due to the standing wave present along the conductor. At the resonant frequency, the standing wave has a current peak and voltage node (minimum) at the feed. In electrical terms, this means the element has minimum reactance, generating the maximum c...
It is possible to use the impedance matching concepts to construct vertical antennas substantially shorter than the 1⁄4 wavelength at which the antenna is resonant. By adding an inductance in series with the antenna, a so-called loading coil, the capacitive reactance of this antenna can be cancelled leaving a pure resi...
The end result is that the resonant antenna will efficiently feed a signal into the transmission line only when the source signal's frequency is close to that of the design frequency of the antenna, or one of the resonant multiples. This makes resonant antenna designs inherently narrowband, and they are most commonly u...
The amount of signal received from a distant transmission source is essentially geometric in nature due to the inverse square law, and this leads to the concept of effective area. This measures the performance of an antenna by comparing the amount of power it generates to the amount of power in the original signal, mea...
Returning to the basic concept of current flows in a conductor, consider what happens if a half-wave dipole is not connected to a feed point, but instead shorted out. Electrically this forms a single 1⁄2-wavelength element. But the overall current pattern is the same; the current will be zero at the two ends, and reach...
A Yagi-Uda array uses passive elements to greatly increase gain. It is built along a support boom that is pointed toward the signal, and thus sees no induced signal and does not contribute to the antenna's operation. The end closer to the source is referred to as the front. Near the rear is a single active element, typ...
It is also possible to use multiple active elements and combine them together with transmission lines to produce a similar system where the phases add up to reinforce the output. The antenna array and very similar reflective array antenna consist of multiple elements, often half-wave dipoles, spaced out on a plane and ...
Reflection of the original signal also occurs when it hits an extended conductive surface, in a fashion similar to a mirror. This effect can also be used to increase signal through the use of a reflector, normally placed behind the active element and spaced so the reflected signal reaches the element in-phase. Generall...
Another extreme case of impedance matching occurs when using a small loop antenna (usually, but not always, for receiving) at a relatively low frequency where it appears almost as a pure inductor. Resonating such an inductor with a capacitor at the frequency of operation not only cancels the reactance but greatly magni...
Antenna tuning generally refers to cancellation of any reactance seen at the antenna terminals, leaving only a resistive impedance which might or might not be exactly the desired impedance (that of the transmission line). Although an antenna may be designed to have a purely resistive feedpoint impedance (such as a dipo...