878 résultats pour "through"

• X-Ray Astronomy - astronomy.

  Some neutron stars have weaker magnetic fields that allow incoming material to settle onto the entire surface of the neutron star. Eventually, so much material buildsup that the surface layer becomes dense enough to set off a vast thermonuclear explosion, called an outburst. The explosion heats gas to produce X rays. Such aneutron star—called an X-ray burster—can increase its X-ray production by a million times during an outburst. The X-ray glow fades over time, and the binary systementers a lon...

• Swimming.

  the swimmer and the pinky finger should enter the water first. At the same time, the swimmer moves the left arm through the water below the left side of the body.Once in the water, the right arm begins pulling the swimmer forward by bending at the elbow. At the same time the swimmer holds the left arm straight as it reachesthe hip and lifts it out of the water. As the right arm continues to pull, the swimmer rotates slightly onto the right side and swings the left arm up above the head. As the s...

• French Canadian Nationalism - Canadian History.

  The revolution ended in independence for the Americans, who named their new country the United States of America. In the aftermath, thousands of people who hadopposed the American Revolution migrated from what was now the United States to British North America. These people, known as the United Empire Loyalists, settledin the Maritimes, where they greatly increased the British majority over the Acadians, and in Québec. Some settled near francophone communities around Montréal andin the Eastern T...

• Bill Clinton.

  When Arkansas governor David Pryor ran for the U.S. Senate in 1978, Clinton ran for governor. He promised to improve the state’s schools and highways and toimprove economic conditions so that more jobs would be created. At that time, the average income of people in Arkansas ranked 49th among the 50 states. Clinton woneasily, receiving 60 percent of the vote against four opponents in the Democratic primary election and 63 percent against the Republican candidate, Lynn Lowe, in thegeneral election...

• Bill Clinton - USA History.

  When Arkansas governor David Pryor ran for the U.S. Senate in 1978, Clinton ran for governor. He promised to improve the state’s schools and highways and toimprove economic conditions so that more jobs would be created. At that time, the average income of people in Arkansas ranked 49th among the 50 states. Clinton woneasily, receiving 60 percent of the vote against four opponents in the Democratic primary election and 63 percent against the Republican candidate, Lynn Lowe, in thegeneral election...

• The Souls of Black Folk by W.

  in amused contempt and pity. One ever feels his two-ness,—an American, a Negro; two souls, two thoughts, two unreconciled strivings; two warring ideals in onedark body, whose dogged strength alone keeps it from being torn asunder. The history of the American Negro is the history of this strife—this longing to attain self-conscious manhood, to merge his double self into a better and truer self. Inthis merging he wishes neither of the older selves to be lost. He would not Africanize America, f...

• Diving (underwater).

  compensator (or control) device (BCD or BC), which the diver wears as a vest. By adding air to the BCD, the diver becomes more buoyant and rises. By releasing air,the diver becomes less buoyant and sinks. With minor adjustments of air, the diver can achieve neutral buoyancy. A third hose attaches to pressure gauges that diversuse to monitor how much air remains in the tank. A fourth hose attaches to a backup breathing device called an alternate air source, or octopus. Divers also wear a belt w...

• Christmas.

  The new custom of Christmas gift giving allowed the marketplace to exert an unprecedented influence on holiday celebrations. Commercial innovations such asdepartment stores and mass advertising further expanded the custom of exchanging Christmas gifts. Seasonal retail sales helped fuel the economy, causing merchantsand advertisers to become some of the season’s most ardent promoters. Many holiday celebrants regretted these changes, however, and began voicing the nowcommon lament that Christmas h...

• El Salvador - country.

  III PEOPLE The Spanish subjugated the native population of El Salvador in the 16th century. Few Spanish women came to the country, however, so many Spanish men took NativeAmerican women as their mates. Today nearly 90 percent of the population is mestizo , of mixed European and Native American descent. People of purely Native American descent represent about 5 to 10 percent of the population, while people of European descent represent only about 1 percent. El Salvador’s population, 5.2 millio...

• Evolution - biology.

  genetic diversity to extinction. Sexual reproduction ensures that the genes in a population are rearranged in each generation, a process termed recombination. Although the combinations of genes inindividuals change with each new generation, the gene frequency, or ratio of different alleles in the entire population, remains relatively constant if no evolutionaryforces act on the population. One such force is the introduction of new genes into the genetic material of the population, or gene pool...

• Saudi Arabia - country.

  C Natural Resources Some of the world’s largest oil and natural gas fields lie beneath Saudi Arabia and its offshore waters, representing the country’s most economically important naturalresource. In 2007 Saudi Arabia’s oil reserves were estimated at 264 billion barrels. Before the discovery and exploitation of these reserves in the mid-20th century,Saudi Arabia was one of the poorest countries in the world. Its relatively small population subsisted in a harsh environment with little agricultur...

• Colorado (river, North America) - Geography.

  sometime between AD 1300 and 1400, but their descendants, the Hopi and Pueblo people, continue to farm and irrigate using the river's waters. The first European to visit the river was probably Spanish soldier and explorer Francisco de Ulloa, who explored the mouth of the Colorado in 1539. In 1540 and 1541another Spaniard, Francisco Vásquez de Coronado, traveled through much of the region around the Colorado River. An exploring party from the Coronado expedition,led by Garcia López de Cárdenas,...

• Race - biology.

  distributed as a cline, generally varying along a north-south line. Skin color is lightest in northern Europeans, especially in those who live around the Baltic Sea, andbecomes gradually darker as one moves toward southern Europe, the Mediterranean, the Middle East, and into northern Africa and northern subtropical Africa. Skin isdarkest in people who live in the tropical regions of Africa. The lack of clear-cut discontinuities makes any racial boundary based on skin color totally arbitrary. Sim...

• Dance I INTRODUCTION Dance Archive Films/BBC Worldwide Americas, Inc.

  features in its dance styles. The ordinary potential of the body can be expanded in dance, usually through long periods of specialized training. In ballet, for example, the dancer exercises to rotate,or turn out, the legs at the hips, making it possible to lift the leg high in an arabesque. In India, some dancers learn to choreograph their eyeballs and eyebrows.Costuming can extend the body's capabilities. Toe or pointe shoes, stilts, and flying harnesses are a few of the artificial aids employe...

• Electric Motors and Generators.

  the armature. It is often desirable to generate as high a voltage as possible, and rotating armatures are not practical in such applications because of the possibility of sparkingbetween brushes and slip rings and the danger of mechanical failures that might cause short circuits. Alternators are therefore constructed with a stationary armaturewithin which revolves a rotor composed of a number of field magnets. The principle of operation is exactly the same as that of the AC generator described,...

• Poliomyelitis.

  Physical therapy helps patients with paralytic polio stretch and move affected muscles. This movement minimizes the atrophy, or shrinkage, of affected muscles andlimbs and builds strength. Exercises can also retrain working muscles to compensate for other muscles that have permanently lost the ability to move. Rehabilitativetherapy trains patients to use braces, crutches, and other devices that provide support and aid mobility. V PREVENTION OF POLIO Immunization with polio vaccine is the best w...

• Warfare.

  organizations as the League of Nations in 1920 and the United Nations in 1945, and détente (suggested for scaling down the cold war). See Arms Control. Modern antiwar sentiment and organized peace movements are derived in large part from the beliefs of religious sects such as the Society of Friends and the MennoniteChurch. The first peace societies in history were established in the U.S. in 1815, and since then pacifists have actively opposed wars and conscription, and promoted thecause of con...

• Elephant - biology.

  B Trunk An elephant's nose and upper lip are combined in a long, limber trunk, an exceptionally supple appendage with an estimated 150,000 muscles. The versatile trunk actslike a hand for grasping low-growing shrubs and other food and placing it into the mouth; an arm for breaking off tree branches; or a snorkel for breathing when theelephant's body is submerged. Elephants also use their trunks to suck up water and squirt it into their mouths for drinking or over their bodies for bathing. Nostr...

• Human Nutrition.

  is one of the most preventable types of cancer. Nutritionists caution that most Americans need to eat more complex carbohydrates. In the typical American diet, only 40 to 50 percent of total calories come fromcarbohydrates—a lower percentage than found in most of the world. To make matters worse, half of the carbohydrate calories consumed by the typical American comefrom processed foods filled with simple sugars. Experts recommend that these foods make up no more that 10 percent of our diet, bec...

• Cell (biology) - biology.

  proteins, or other proteins required by the cell. While relatively simple in construction, prokaryotic cells display extremely complex activity. They have a greater range of biochemical reactions than those found in theirlarger relatives, the eukaryotic cells. The extraordinary biochemical diversity of prokaryotic cells is manifested in the wide-ranging lifestyles of the archaebacteria andthe bacteria, whose habitats include polar ice, deserts, and hydrothermal vents—deep regions of the ocean un...

• Welfare.

  industrializing societies. Governments typically financed social insurance programs with tax funds and direct levies on the wages of potential recipients. Social insurancereplaced part of incomes lost when workers became disabled, were laid off, or had reached an age that forced them out of the labor market. Later, governments of Germany, France, Belgium, Sweden, and other countries developed forms of social insurance that provided population-wide, or universal,coverage. Such forms included chil...

• Orthodox Church.

  formally defined by an ecumenical council, as it was in Catholicism, some Orthodox theologians have taught that the act of becoming a monk or the service of burial canalso be sacraments. The sacramental practice of the Orthodox differs in many details from Western customs. Baptism is administered by immersing the child or adult three times under thewater, each time in the name of one of the persons of the Trinity. It is followed immediately by anointment with chrism, a sacred perfumed oil that r...

• USA - Iraq War - History.

  B Making the Case for War B1 “Neoconservatives” and the Bush Doctrine Long before President George W. Bush took office in 2001, elements in or close to the Republican Party had called repeatedly for firmer U.S. steps against Iraq,including a war if necessary to force a regime change. One such group authored a white paper in 1996 called A Clean Break: A New Strategy for Securing the Realm , which was later sent to Prime Minister Benjamin Netanyahu, leader of Israel’s Likud Party. It advocated...

• U.S.-Iraq War - U.S. History. I INTRODUCTION U.S.-Iraq War, military action begun in

  B Making the Case for War B1 “Neoconservatives” and the Bush Doctrine Long before President George W. Bush took office in 2001, elements in or close to the Republican Party had called repeatedly for firmer U.S. steps against Iraq,including a war if necessary to force a regime change. One such group authored a white paper in 1996 called A Clean Break: A New Strategy for Securing the Realm , which was later sent to Prime Minister Benjamin Netanyahu, leader of Israel’s Likud Party. It advocated...

• Pennsylvania - geography.

  B Rivers and Lakes There are three major river basins in Pennsylvania: the Susquehanna, the Ohio, and the Delaware. Together they drain more than 90 percent of Pennsylvania’s landarea. Most of eastern and central Pennsylvania is drained by the Susquehanna and Delaware systems. The western part of the state is drained by the Allegheny andMonongahela rivers, which join at Pittsburgh to form the Ohio. In addition to the three major river basins, short streams flowing into Lake Erie drain the north...

• Pennsylvania - USA History.

  B Rivers and Lakes There are three major river basins in Pennsylvania: the Susquehanna, the Ohio, and the Delaware. Together they drain more than 90 percent of Pennsylvania’s landarea. Most of eastern and central Pennsylvania is drained by the Susquehanna and Delaware systems. The western part of the state is drained by the Allegheny andMonongahela rivers, which join at Pittsburgh to form the Ohio. In addition to the three major river basins, short streams flowing into Lake Erie drain the north...

• New Mexico - geography.

  New Mexico’s major river is the Río Grande, originating in southern Colorado, and flowing southward for 760 km (470 mi) through the state. Between the San LuisValley and Española Valley the river flows in a deep canyon known as the Río Grande Gorge; then, below White Rock Canyon, it flows through several valleys containingagricultural land. Most of the water of the Río Grande is used to irrigate these valleys. The Río Grande’s waterflow in New Mexico is extremely low. One of the major tributarie...

• New Mexico - USA History.

  New Mexico’s major river is the Río Grande, originating in southern Colorado, and flowing southward for 760 km (470 mi) through the state. Between the San LuisValley and Española Valley the river flows in a deep canyon known as the Río Grande Gorge; then, below White Rock Canyon, it flows through several valleys containingagricultural land. Most of the water of the Río Grande is used to irrigate these valleys. The Río Grande’s waterflow in New Mexico is extremely low. One of the major tributarie...

• Yangtze - geography.

  Yangtze Gorges, ChinaThe Yangtze Gorges, also known as the Three Gorges, once drew many tourists with their scenic beauty. However, the Three GorgesDam that was constructed in the early 21st century raised the level of the Yangtze River upstream, forming a deep reservoir thatflooded the gorges.Dean Conger/Corbis The Yangtze originates in the mountains of southwestern Qinghai Province, located in the northern Tibetan Plateau. The river has three headwaters, the highest of whichdescends from an el...

• Magnetism I INTRODUCTION Magnetism, an aspect of electromagnetism, one of the fundamental forces of nature.

  the French physicist Paul Langevin produced a theory regarding the temperature dependence of the magnetic properties of paramagnets (discussed below), which wasbased on the atomic structure of matter. This theory is an early example of the description of large-scale properties in terms of the properties of electrons and atoms.Langevin's theory was subsequently expanded by the French physicist Pierre Ernst Weiss, who postulated the existence of an internal, “molecular” magnetic field inmaterials...

• San Antonio (city, Texas) - geography.

  The SBC Center is the home venue for the San Antonio Spurs of the National Basketball Association (NBA) and the San Antonio Silver Stars of the Women's NationalBasketball Association (WNBA). The dome also serves as the site for the Alamo Bowl, an annual post-season college football game. Large themed amusement parks inthe San Antonio area are Fiesta Texas and Sea World of Texas. San Antonio’s major annual event is the Fiesta, a ten-day celebration in late April with carnivals, ethnic feasts, art...

• Helicopter.

  naturally flaps down so as to increase lift. Flapping allows the differences in lift caused by uneven rotor tip speed to cancel out, producing a stable ride. Many helicoptersuse mechanical hinges with lubricated bearings, but some use flexible straps made of a composite material in order to reduce the required maintenance. Helicopters require different amounts of lift and thrust at different times during flight, because the aerodynamic forces acting on them change during hovering andacceleration...

• Asia - geography.

  the Himalayas, the world’s highest mountain system. The Pacific Ocean plate drifted westward, scraping along the Eurasian plate and slipping under its coastal edge. This created the islands of Japan, Taiwan, the Kurils, theRyūky ūs, and the Philippines. Southeast Asia lies at the intersection of the Eurasian, Pacific Ocean, and Indian Ocean plates. Over time the contact between these platescreated the mountain ranges of mainland Southeast Asia. The continued slow movement of the plates causes fr...

• Asia - history.

  the Himalayas, the world’s highest mountain system. The Pacific Ocean plate drifted westward, scraping along the Eurasian plate and slipping under its coastal edge. This created the islands of Japan, Taiwan, the Kurils, theRyūky ūs, and the Philippines. Southeast Asia lies at the intersection of the Eurasian, Pacific Ocean, and Indian Ocean plates. Over time the contact between these platescreated the mountain ranges of mainland Southeast Asia. The continued slow movement of the plates causes fr...

• Gothic Art and Architecture I INTRODUCTION Notre Dame Cathedral, Paris Notre Dame Cathedral, in Paris, was begun in 1163 and completed for the most part in 1250.

  and by external arches, called flying buttresses. Consequently, the thick walls of Romanesque architecture could be largely replaced by thinner walls with glass windows,and the interiors could reach unprecedented heights. A revolution in building techniques thus occurred. With the Gothic vault, a ground plan could take on a variety of shapes. The general plan of the cathedrals, however, consisting of a long three-aisled nave interceptedby a transept and followed by a shorter choir and sanctuary,...

• Animation I INTRODUCTION Finding Nemo A clown fish named Marlin, left, and his friend Dory search for Marlin's son in the computer-animated feature film Finding Nemo (2003).

  Animator at WorkAnimators use computers for every part of the animation process, from creating a storyboard (a scene-by-sceneillustration of the plot) to imitating camera movement. This animator is creating a scene for the motion picture Antz(1998).C. Lepetit/Liaison Agency If an animator is basing the animation project on drawings, one of the most common animation techniques, he or she will first create a series of rough sketches thatoften will be filmed in a pencil test (simple line drawings...

• First Americans.

  bones and artifacts helped 19th-century archaeologists establish the age of ancient human encampments in Europe. Yet, search as they might, American archaeologists found no comparable evidence of a Pleistocene-era human presence. But several sites revealed stone artifacts thatsome scholars believed looked similar to the ancient stone tools found in Europe. On the basis of this similarity, these experts claimed the American artifacts must be asold. By the 1890s, however, other scholars had challe...

• First Americans - Canadian History.

  bones and artifacts helped 19th-century archaeologists establish the age of ancient human encampments in Europe. Yet, search as they might, American archaeologists found no comparable evidence of a Pleistocene-era human presence. But several sites revealed stone artifacts thatsome scholars believed looked similar to the ancient stone tools found in Europe. On the basis of this similarity, these experts claimed the American artifacts must be asold. By the 1890s, however, other scholars had challe...

• Russian Revolutions of 1917 (Histoire) .

  as Marxists. They believed that the working class—with its struggles to organize trade unions and to bring about political reforms of benefit to the majority ofpeople—would become the primary force for revolutionary change. The Russian Marxists formed the Russian Social Democratic Labor Party (RSDLP) in 1898. By 1903,however, the RSDLP had split into two factions. The faction called the Bolsheviks (from the Russian word for “majority”), led by Vladimir Ilich Lenin, favored a more centralized a...

• California - geography.

  The Basin and Range province is an arid area of mountain ranges, basins, and deserts. In California it is represented primarily by parts of the Great Basin and SonoranDesert sections. Within the Great Basin lies Death Valley, whose lowest elevation, 86 m (282 ft) below sea level, is the lowest point in the Western Hemisphere. TheSonoran Desert section is characterized by numerous flat plains separated by low but rugged ranges. It includes the extensive Mojave, or Mohave, Desert. Also in thisprov...

• California - USA History.

  The Basin and Range province is an arid area of mountain ranges, basins, and deserts. In California it is represented primarily by parts of the Great Basin and SonoranDesert sections. Within the Great Basin lies Death Valley, whose lowest elevation, 86 m (282 ft) below sea level, is the lowest point in the Western Hemisphere. TheSonoran Desert section is characterized by numerous flat plains separated by low but rugged ranges. It includes the extensive Mojave, or Mohave, Desert. Also in thisprov...

• Insects.

  parents. It does not have wings. It may not even have legs. As the insect grows, it starts to changeshape. This change is called metamorphosis. There are two kinds of metamorphosis, called incompleteand complete. Dragonflies, grasshoppers, and crickets are some insects that go through incomplete metamorphosis asthey grow up. The young insects are called nymphs or naiads. The young insect molts, or crawls out ofits exoskeleton, as it grows bigger. It grows a new, larger exoskeleton. Its body chan...

• Pyramids (Egypt) - geography.

  displayed in its full majesty. B Interior The interior of the Great Pyramid is complex, with a series of passages leading to several rooms. The most important room is the King’s Chamber, the room in which Khufu’sbody was placed during his funeral. In this room the priests left items that Khufu, like all Egyptians, would need for the afterlife. Although the builders tried to blockpassages and doors when they left the pyramid after the king’s funeral, tomb robbers did eventually take everything o...

• From "Song of Myself" - anthology.

  Till that becomes unseen and receives proof in its turn.Showing the best and dividing it from the worst age vexes age,Knowing the perfect fitness and equanimity of things, while they discuss I am silent, and go bathe and admire myself.Welcome is every organ and attribute of me, and of any man hearty and clean,Not an inch nor a particle of an inch is vile, and none shall be less familiar than the rest.I am satisfied—I see, dance, laugh, sing;As the hugging and loving bed-fellow sleeps at my side...

• Calligraphy I INTRODUCTION Japanese Calligraphy This hanging scroll is an example of Japanese calligraphy.

  Section of the Egyptian Book of the DeadThe Egyptian Book of the Dead was a text containing prayers, spells, and hymns, the knowledge of which was to be usedby the dead to guide and protect the soul on the hazardous journey through the afterlife. This section of one such book,dating from the early 19th Dynasty, shows the final judgment of the deceased (in this case Hu-Nefer, the royal scribe)before Osiris, the god of the dead. Hieroglyphs as well as illustrations portray the ritual of weighing t...

• Mount Everest - geography.

  endangered or killed when their tents collapsed or were ripped to shreds by the gales. Hypothermia, the dramatic loss of body heat, is also a major and debilitatingproblem in this region of high winds and low temperatures. Another hazard facing Everest climbers is the famous Khumbu icefall, which is located not far above Base Camp and is caused by the rapid movement of the Khumbuglacier over the steep rock underneath. The movement breaks the ice into sérac (large, pointed masses of ice) cliffs...

• WHY I'M NOT WHERE YOU ARE 5/21/63   Your mother and I never talk about the past, that's a rule.

  under theNothing doorandstained theSomething hallway,there'snothing tosay. Itbecame difficulttonavigate from Something toSomething withoutaccidentally walkingthrough Nothing, andwhen Something—a key,apen, a pocketwatch—was accidentallyleftinaNothing Place,itnever couldberetrieved, thatwasanunspoken rule,likenearly all ofour rules havebeen. There cameapoint, ayear ortwo ago, when ourapartment wasmore Nothing than Something, thatinitself didn't havetobe aproblem, itcould havebeen agood thing, itco...

• Sexually Transmitted Infections.

  D Genital Herpes Genital herpes is caused by infection with the herpes simplex virus (HSV). Most cases of genital herpes are due to HSV type 2. Some cases, however, result from genitalinfections with HSV type 1, a common cause of cold sores. Genital herpes causes recurrent outbreaks of painful sores on the genitals, although the disease oftenremains dormant with no symptoms for long periods. In the United States, one in five individuals over the age of 12 is infected with HSV type 2, and the va...

• Wireless Communications.

  were large, heavy units. After the invention of the transistor in 1948, radios shrank in size to small handheld radio transceivers. Public two-way radios with severalfrequency options are widely available as well. Usually limited in range to a few miles, these units are great aids for such mobile professionals as construction workers,film crews, event planners, and security personnel. Simpler two-way radios, called walkie-talkies, have been popular children’s toys for years. Most walkie-talkiesb...

• Genetic Engineering.

  Pseudomonas fluorescens bacterium. The genetically altered Pseudomonas fluorescens bacterium produces light in proportion to the amount of its activity in breaking down the naphthalene, thus providing a way to monitor the efficiency of the process ( see Bioremediation). A3 Medicine In 1982 the United States Food and Drug Administration (FDA) approved for the first time the medical use of a recombinant DNA protein, the hormone insulin, whichhad been cloned in large quantities by inserting th...