1327 résultats pour "than"

• Terrorism.

  exploitation, ethnic discrimination, and religious persecution. Perceived inequities in the distribution of wealth and political power have led some terrorists to attempt tooverthrow democratically elected governments. To achieve a fairer society, they would replace these governments with socialist or communist regimes. Left-wingterrorist groups of the 1960s and 1970s with such aims included Germany’s Baader-Meinhof Gang, Italy’s Red Brigades, and the Weather Underground ( see Weathermen) in the...

• Florida - USA History.

  accidentally introduced into the region in the 1880s, and it spread with alarming rapidity throughout the upper reaches of the river. The plant is very difficult toeradicate, and it has also clogged the channels of other Florida rivers. To increase drainage of the Everglades, which drain naturally to Florida Bay and the Gulf ofMexico, a number of drainage channels and canals have been built across southern Florida. Among the rivers flowing from the peninsula to the Gulf of Mexico are the Suwanne...

• Gemstones.

  In the late 1960s a method was developed for “growing” diamonds by heating a diamond particle to a high temperature and subjecting it to methane gas. The gasdecomposes into carbon atoms, which adhere to the diamond crystal. The crystal structure of the enlarged diamond is identical to that of a natural diamond. Diamondsof about 1 carat (200 mg or 0.007 oz) have been produced by this method, but their cost is still considerably higher than that of naturally occurring diamonds. Sapphires are made...

• Segregation in the United States - U.

  acts of discrimination. Writing for the court, Justice Joseph Bradley declared: “When a man has emerged from slavery, and by the aid of beneficent legislation ... theremust be some stage in the progress of his elevation when he takes the rank of a mere citizen, and ceases to be the special favorite of the laws, and when his rights as acitizen, or a man, are to be protected in the ordinary modes by which other men’s rights are protected.” Rather than being the “special favorites” of the law, blac...

• Heredity - biology.

  allele from the mother and a mutated allele from the father. In both of these cases, the child will be a carrier. The child develops the disease only if he or she receives amutated allele from each parent. When both parents are carriers, there is a 25 percent chance that a child will be disease-free, a 25 percent chance that it will have thedisease, and a 50 percent chance that it will be a carrier. Examples of genetic diseases that follow the dominant-recessive pattern include sickle-cell anemi...

• Excerpt from The Winter's Tale - anthology.

  Of all that hear me, and my near'st of kinCry fie upon my grave! LEONTES. I ne'er heard yetThat any of these holder vices wantedLess impudence to gainsay what they didThan to perform it first. HERMIONE. That's true enough,Though 'tis a saying, sir, not due to me. LEONTES. You will not own it. HERMIONE. More than mistress ofWhich comes to me in name of fault I must notAt all acknowledge. For Polixenes,With whom I am accused, I do confessI loved him as in honour he required:With such a kind of lov...

• Public Education in the United States.

  opportunities for them to break out from whatever social or economic circumstances constrained their development. IV HIGHER EDUCATION During the 20th century participation in higher or postsecondary education in the United States increased as dramatically as it did in American high schools. At thebeginning of the century about 2 percent of Americans from the ages of 18 to 24 were enrolled in a college. There were fewer than 1,000 colleges then, with enrollmenttotaling about 157,000 students. N...

• Slavery in the United States - U.

  tripled, from about 1.2 million to almost 4 million in 1860. The natural growth of the slave population meant that slavery could survive without new slave imports. Natural population growth also hastened the transition from an African to an African American slave population. By the 1770s, only about 20 percent of slaves in thecolonies were African-born, although the concentration of Africans remained higher in South Carolina and Georgia. After 1808 the proportion of African-born slavesbecame tin...

• Machine I INTRODUCTION Machine, simple device that affects the force, or effort, needed to do a certain amount of work.

  to decrease the amount of force needed to do work or to change the direction of the force. The wheel and axle and some levers can also be used to increase the speedof performance of a task, but doing so always increases the amount of force needed. A Inclined Plane NutsNuts are pieces of metal with a hole in the middle. They are screwed on the end of a bolt as a fastening. Nuts come invarying shapes, depending on their intended use.© Microsoft Corporation. All Rights Reserved. Ramps and staircas...

• Jupiter (planet) - astronomy.

  Beneath the supercritical fluid zone, the pressure reaches 3 million Earth atmospheres. At this depth, the atoms collide so frequently and violently that the hydrogenatoms are ionized—that is, the negatively charged electrons are stripped away from the positively charged protons of the hydrogen nuclei. This ionization results in asea of electrically charged particles that resembles a liquid metal and gives rise to Jupiter’s magnetic field. This liquid metallic hydrogen zone is 30,000 to 40,000 k...

• Pollution.

  One of the greatest challenges caused by air pollution is global warming, an increase in Earth’s temperature due to the buildup of certain atmospheric gases such ascarbon dioxide. With the heavy use of fossil fuels in the 20th century, atmospheric concentrations of carbon dioxide have risen dramatically. Carbon dioxide and othergases, known as greenhouse gases, reduce the escape of heat from the planet without blocking radiation coming from the Sun. Because of this greenhouse effect,average glob...

• Big Bang Theory - astronomy.

  hydrogen atoms. Hydrogen atoms can only absorb and emit specific colors, or wavelengths, of light. The formation of atoms allowed many other wavelengths of light,wavelengths that had been interfering with the free electrons prior to the cooling of the universe, to travel much farther than before. This change set free radiation thatwe can detect today. After billions of years of cooling, this cosmic background radiation is at about 3 K (-270°C/-454°F).The cosmic background radiation was first d...

• Planetary Science - astronomy.

  III ORIGINS AND COMPOSITIONS OF PLANETS Astronomers believe that planetary systems are formed of elemental materials that were created in the interiors of giant stars. Some of this material comes from giantstars that shed material into space as they age. Most of the matter to form planets, however, comes from stars that explode as supernovas and spread debris enrichedwith the heavier chemical elements into space. According to the currently accepted views, the most likely first stage in the evo...

• Light I INTRODUCTION Light, form of energy visible to the human eye that is radiated by moving charged particles.

  simulates the action of a moving charge upon the electric field. It creates a wave that travels along the rope in a direction that is perpendicular to the initial up anddown movement. Because electromagnetic waves are transverse—that is, the vibration that creates them is perpendicular to the direction in which they travel, they are similar to waveson a rope or waves traveling on the surface of water. Unlike these waves, however, which require a rope or water, light does not need a medium, or su...

• Hong Kong - geography.

  higher than China’s average standard of living. In 2006 Hong Kong’s per capita gross domestic product (GDP) was $27,679.20, although much of the wealth isconcentrated into relatively few hands. IV ECONOMY Hong Kong’s position as one of the world’s most important economic centers is based on several factors. It is located midway between Japan and Singapore, and it liesastride the main shipping and air routes of the western Pacific. It also has long served as a major port of entry and trade for...

• Radio Astronomy - astronomy.

  equivalent to the apparent angular dimensions of a basketball at the distance of the moon. In 1984, the U.S. government appropriated funds for the construction of aninstallation called the very long baseline array (VLBA), a network of 10 radio antennas spread from the U.S.-Canadian border to Puerto Rico and from Hawaii to the U.S.Atlantic coast. The VLBA is expected to provide angular resolutions in the range of 200-millionths of an arc second. Canada and Australia are both planning similarprogr...

• Coronary Heart Disease.

  when a patient is at rest may indicate that the blood supply of the heart is not normal, and the ECG can often detect damage from a previous heart attack. In anexercise stress test, an ECG is recorded while a patient is performing physical activity such as walking on a treadmill or riding a stationary bicycle. As the intensity ofexercise increases, the doctor looks for specific changes in the ECG that indicate the heart is not getting enough oxygen. In cardiac catheterization, a long, thin, flex...

• Stock Exchange.

  A Example of a Trade In an example of a trade, an investor wanting to buy 200 shares—also known as two round lots, of 100 shares each—of IBM stock will telephone or e-mail the order to abrokerage firm. This communication is normally made to an individual called a stockbroker. The investor might desire to buy the shares at the market, or current, price.On the other hand, the investor may choose to pay no more than a set amount per share. The brokerage firm then contacts one of its floor brokers...

• Radioactivity I INTRODUCTION Marie Curie Working with her husband, Pierre Curie, French physicist Marie Curie discovered the radioactive elements polonium and radium in 1898.

  Rutherford when he allowed an alpha-emitting substance to decay near an evacuated thin-glass vessel. The alpha particles were able to penetrate the glass and werethen trapped in the vessel, and within a few days the presence of elemental helium was demonstrated by use of a spectroscope. Beta particles were subsequentlyshown to be electrons, and gamma rays to consist of electromagnetic radiation of the same nature as X rays but of considerably greater energy. A The Nuclear Hypothesis Rutherford...

• World Energy Supply.

  In the 1990s, oil production by non-OPEC countries remained strong and production by OPEC countries rebounded. The result at the end of the 20th century was aworld oil surplus and prices (when adjusted for inflation) that were lower than in 1972. Experts are uncertain about future oil supplies and prices. Low prices have spurred greater oil consumption, and experts question how long world petroleum reservescan keep pace with increased demand. Many of the world’s leading petroleum geologists beli...

• Smoking.

  causes about 20 times the number of deaths in the United States than all other addictive drugs combined. Smoking cessation methods are plentiful, and many books and products are available to help an individual stop smoking. Many smokers turn to group help because ofthe support and understanding provided by other former smokers or people trying to quit. Most successful group-help techniques involve a challenge and rewardsystem that also bolsters the self-discipline of the former smoker. A number...

• Electronic Games.

  arcade game of all time. With Pizza Time Theaters legitimizing the idea of arcades and hits such as Ms. Pac-Man , Asteroids , Donkey Kong , Tempest , Frogger , and Defender bringing new excitement to gaming, the coin-operated video game business boomed. In 1981 Americans spent 75,000 person-years and $5 billion playing video games at anestimated 4,300 arcades in the United States. Many popular arcade games also were translated for use on the Atari 2600 and its chief rivals in the homemarket—M...

• Automobile Racing.

  beginning in 1906 at Le Mans it came to refer to the principal F1 auto race in a given nation, except in the United States, where the term continues to be used lessdiscriminately. After the end of World War I in 1918, when automobile racing blossomed internationally, a series of GP races in several nations became reserved for F1competition, and an annual GP calendar was developed consisting of national races, such as the French Grand Prix and the British Grand Prix. An annual award calledthe Wor...

• Memory (psychology).

  memory span —how many items people can correctly recall in order. Researchers would show people increasingly long sequences of digits or letters and then ask them to recall as many of the items as they could. In 1956 American psychologist George Miller reviewed many experiments on memory span and concluded that peoplecould hold an average of seven items in short-term memory. He referred to this limit as “the magical number seven, plus or minus two” because the results of thestudies were so consi...

• Railroads.

  III GAUGES The gauge of track is the distance between the inner edges of the rails at points 1.59 cm (0.626 in) below the top of the heads. In the United States, Canada, theUnited Kingdom, Mexico, Norway, Sweden, and much of continental Europe, the standard gauge is 143.51 cm (56.5 in). Why this measurement became the standard isa matter of speculation. Probably the tradition is inherited from early tramroads built to accommodate wagons with axles 1.5 m (5 ft) long; some of the early edge rail...

• Central America - Geography.

  F Animal Life Most of the animal life of Central America is similar to that of South America, but some animals have ties with North America. The marley and opossum have links withSouth America, as do the jaguar, ocelot, jaguarundi, and margay, which are members of the cat family. In contrast, the puma, gray fox, and coyote are of NorthAmerican origin. The armadillo, anteater, and sloth have ties to the south, deer to the north. The large manatee, an aquatic plant eater, survives in the isolated...

• 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...

• Uganda - country.

  Uganda’s population is predominantly rural and is concentrated in the south, particularly in the crescent at the edge of Lake Victoria and in the southwest. Almost allUgandans are black Africans. Foreign residents make up less than 4 percent of the population and come mostly from neighboring states. In 2008 Uganda’s population was estimated at 31,367,972. The estimated growth rate of the population in 2008 was 3.6 percent. The birth rate was 48 per 1,000people and the death rate 12 per 1,000. Th...

• Light - astronomy.

  Each different frequency or wavelength of visible light causes our eye to see a slightly different color. The longest wavelength we can see is deep red at about 700 nm.The shortest wavelength humans can detect is deep blue or violet at about 400 nm. Most light sources do not radiate monochromatic light. What we call white light,such as light from the Sun, is a mixture of all the colors in the visible spectrum, with some represented more strongly than others. Human eyes respond best to greenlight...

• Asteroid - astronomy.

  Asteroids of the S type, related to the stony iron meteorites, make up about 15 percent of the total population of asteroids that can be seen from Earth. Much rarer arethe M-type objects, corresponding in composition to the meteorites known as “irons.” These objects are made up of an iron-nickel alloy and may represent the cores ofbodies that were large enough to differentiate into layers and to melt deep inside. Their rocky outer layers may have been removed by impacts with other asteroids . A...

• France - country.

  In both the Paris and Aquitaine basins, fertile soils derived from limestone and wind-deposited dust, called loess, have supported prosperous agriculture since ancienttimes. Other lowlands in France are scattered and relatively small. They include the Alsace Plain in the east, bordering Germany, the valley of the Rhône River in thesoutheast, and the Languedoc Plain along the Mediterranean coast. A2 Uplands France contains several regions of uplands, the worn down remains of ancient mountain sys...

• British Columbia - Geography.

  hemlock, Douglas fir, Sitka spruce, and various cedars, grows rapidly in the mild, wet climate and produces the largest trees in Canada. In the dry lowlands of thesouthern and central interior, ponderosa and lodgepole pines, aspen, and bunchgrass are characteristic. Spruce dominates the Prince George region. Prairie grasses andstands of aspen are found in the northeastern corner of the province. At elevations higher than about 1,800 m (about 6,000 ft), an alpine vegetation of shrubs, mosses,and...

• British Columbia - Canadian History.

  hemlock, Douglas fir, Sitka spruce, and various cedars, grows rapidly in the mild, wet climate and produces the largest trees in Canada. In the dry lowlands of thesouthern and central interior, ponderosa and lodgepole pines, aspen, and bunchgrass are characteristic. Spruce dominates the Prince George region. Prairie grasses andstands of aspen are found in the northeastern corner of the province. At elevations higher than about 1,800 m (about 6,000 ft), an alpine vegetation of shrubs, mosses,and...

• Oklahoma - geography.

  portion and the Panhandle are classified as a steppe, where precipitation, typically 250 to 500 mm (10 to 20 in), is the controlling characteristic. January is usually the coldest month with an average of about 3°C (38°F) and extremes from -33°C (-27°F), the lowest ever recorded, to 33°C (92°F). Summer arelong and hot with temperatures in the upper 30°s C (lower 100°s F) common from May until September across the state. The growing season varies from less than 180days in the western Panhandle to...

• Oklahoma - USA History.

  portion and the Panhandle are classified as a steppe, where precipitation, typically 250 to 500 mm (10 to 20 in), is the controlling characteristic. January is usually the coldest month with an average of about 3°C (38°F) and extremes from -33°C (-27°F), the lowest ever recorded, to 33°C (92°F). Summer arelong and hot with temperatures in the upper 30°s C (lower 100°s F) common from May until September across the state. The growing season varies from less than 180days in the western Panhandle to...

• Delaware - geography.

  D Climate Delaware has generally hot and humid summers and mild winters. D1 Temperature In July, average daytime temperatures are usually in the upper 20°s to lower 30°sC (80°sF) or even higher. But because summer nights tend to be cooler than thedays, July averages are about 24°C (about 75°F). In addition, onshore sea breezes can reduce daytime temperatures along the coast by 3 to 6 Celsius degrees (5 to 10Fahrenheit degrees). January averages range from -1°C (31°F) at Newark, in the north, t...

• Delaware - USA History.

  D Climate Delaware has generally hot and humid summers and mild winters. D1 Temperature In July, average daytime temperatures are usually in the upper 20°s to lower 30°sC (80°sF) or even higher. But because summer nights tend to be cooler than thedays, July averages are about 24°C (about 75°F). In addition, onshore sea breezes can reduce daytime temperatures along the coast by 3 to 6 Celsius degrees (5 to 10Fahrenheit degrees). January averages range from -1°C (31°F) at Newark, in the north, t...

• Dwight D.

  maneuvers in Louisiana in 1941, he played a leading role as a staff officer, adding to his reputation and securing him a promotion to brigadier general. On December 7,1941, Japan attacked Pearl Harbor, Hawaii, and the next day the United States entered World War II against the Axis Powers (Japan, Germany, and Italy). A weeklater, the army’s new chief of staff, General George C. Marshall, called Eisenhower to Washington, D.C., and put him in charge of the War Plans Division. Opinions differed on...

• New York - geography.

  The Adirondack province consists of a large highland area occupying 26,000 sq km (10,000 sq mi) in the northeastern quarter of the state. The region is domelike inshape, with the higher elevations toward the east. The western Adirondack province is more a rugged hill region and not truly mountainous. Geologically, this area isrelated to the Laurentian Upland, or Canadian Shield, which lies north of the St. Lawrence River, for it is composed of the same very old igneous rocks, principallygranite...

• New York - USA History.

  The Adirondack province consists of a large highland area occupying 26,000 sq km (10,000 sq mi) in the northeastern quarter of the state. The region is domelike inshape, with the higher elevations toward the east. The western Adirondack province is more a rugged hill region and not truly mountainous. Geologically, this area isrelated to the Laurentian Upland, or Canadian Shield, which lies north of the St. Lawrence River, for it is composed of the same very old igneous rocks, principallygranite...

• Missouri - geography.

  Saint Francois Mountains, at the eastern end of the crest of the dome. Only in these mountains have the sedimentary rocks been sufficiently eroded away so that theunderlying igneous rocks are exposed. They form the rounded, knoblike peaks of an old mountain range. The peaks project, in isolation or in clusters, between 230 and300 m (750 and 1,000 ft) above the surrounding sedimentary basins. One of these knobs, Taum Sauk Mountain, reaches 540 m (1,772 ft) above sea level and is thehighest point...

• Missouri - USA History.

  Saint Francois Mountains, at the eastern end of the crest of the dome. Only in these mountains have the sedimentary rocks been sufficiently eroded away so that theunderlying igneous rocks are exposed. They form the rounded, knoblike peaks of an old mountain range. The peaks project, in isolation or in clusters, between 230 and300 m (750 and 1,000 ft) above the surrounding sedimentary basins. One of these knobs, Taum Sauk Mountain, reaches 540 m (1,772 ft) above sea level and is thehighest point...

• Australia - country.

  itself forms most of the border between New South Wales and Victoria. Considerable lengths of the Murray, Darling, and Murrumbidgee rivers are navigable during thewet seasons. The central plains region, also known as the Channel Country, is interlaced by a network of rivers. During the rainy season these rivers flood the low-lying countryside,but in dry months they become merely a series of water holes. The Victoria, Daly, and Roper rivers drain a section of the Northern Territory. In Queensland...

• Australia - Geography.

  itself forms most of the border between New South Wales and Victoria. Considerable lengths of the Murray, Darling, and Murrumbidgee rivers are navigable during thewet seasons. The central plains region, also known as the Channel Country, is interlaced by a network of rivers. During the rainy season these rivers flood the low-lying countryside,but in dry months they become merely a series of water holes. The Victoria, Daly, and Roper rivers drain a section of the Northern Territory. In Queensland...

• Native Americans of North America.

  addition to smallpox and measles, explorers and colonists brought a host of other diseases: bubonic plague, cholera, typhoid fever, scarlet fever, pleurisy, mumps,diphtheria, pneumonia, whooping cough, malaria, yellow fever, and various sexually transmitted infections. Despite the undisputed devastation wreaked on Indian populations after European contact, native populations showed enormous regional variability in their response todisease exposure. Some peoples survived and, in some cases, even...

• Native Americans of North America - Canadian History.

  addition to smallpox and measles, explorers and colonists brought a host of other diseases: bubonic plague, cholera, typhoid fever, scarlet fever, pleurisy, mumps,diphtheria, pneumonia, whooping cough, malaria, yellow fever, and various sexually transmitted infections. Despite the undisputed devastation wreaked on Indian populations after European contact, native populations showed enormous regional variability in their response todisease exposure. Some peoples survived and, in some cases, even...

• Louisiana - geography.

  lakes are on the Red River and its tributaries. In addition, small oxbow lakes are numerous in the Mississippi Alluvial Plain. Oxbow lakes are formed when a river cutsthrough the neck of one of its loops, or meanders, thus establishing a shorter course and leaving the former loop as a lake separate from the river. Louisiana also hassome artificially created reservoirs. C Coastline Louisiana’s long and irregular coastline extends along the Gulf of Mexico from the Pearl River on the east to the S...

• Louisiana - USA History.

  lakes are on the Red River and its tributaries. In addition, small oxbow lakes are numerous in the Mississippi Alluvial Plain. Oxbow lakes are formed when a river cutsthrough the neck of one of its loops, or meanders, thus establishing a shorter course and leaving the former loop as a lake separate from the river. Louisiana also hassome artificially created reservoirs. C Coastline Louisiana’s long and irregular coastline extends along the Gulf of Mexico from the Pearl River on the east to the S...

• Giant Panda - biology.

  In 2007 conservationists announced that a parasitic roundworm was responsible for a significant number of the panda deaths reported in the wild since 1990. Theparasite Baylisascaris schroederi causes the disease visceral larval migrans, which results in bleeding in the lungs, the liver, and the intestines, and can also affect the brain. It is not known if other recent pandas deaths were caused by the same parasite or by a different contagious disease. Loss of habitat from deforestation is forc...

• Ant - biology.

  The workers of many ant species carry a stinger within the hind end of the gaster. These ants use the stinger to defend against their enemies. In some species, workerants lack a stinger but use the tip of their gaster to squirt or dab poison at other small animals and when fighting battles with other ants, fending off predators, or killinginsects or other animals that they use as food. III PHYSIOLOGY Ants have a rigid, external skeleton called an exoskeleton that gives the soft, inner body its...