1174 résultats pour "two"

• William Shakespeare I INTRODUCTION William Shakespeare (1564-1616), English playwright and poet, recognized in much of the world as the greatest of all dramatists.

  Shakespeare’s reputation today is, however, based primarily on the 38 plays that he wrote, modified, or collaborated on. Records of Shakespeare’s plays begin toappear in 1594, when the theaters reopened with the passing of the plague that had closed them for 21 months. In December of 1594 his play The Comedy of Errors was performed in London during the Christmas revels at Gray’s Inn, one of the London law schools. In March of the following year he received payment for two playsthat had been per...

• William Shakespeare.

  Shakespeare’s reputation today is, however, based primarily on the 38 plays that he wrote, modified, or collaborated on. Records of Shakespeare’s plays begin toappear in 1594, when the theaters reopened with the passing of the plague that had closed them for 21 months. In December of 1594 his play The Comedy of Errors was performed in London during the Christmas revels at Gray’s Inn, one of the London law schools. In March of the following year he received payment for two playsthat had been per...

• Quantum Theory I INTRODUCTION Quantum Theory, in physics, description of the particles that make up matter and how they interact with each other and with energy.

  electron in the same way a particle with momentum would: It bumps the electron and changes the electron’s path. The light is also affected by the collision as though itwere a particle, in that its energy and momentum changes. Momentum is a quantity that can be defined for all particles. For light particles, or photons, momentum depends on the frequency, or color, of the photon, which in turndepends on the photon’s energy. The energy of a photon is equal to a constant number, called Planck’s cons...

• Ice Skating.

  cold climate. Competitors for these events are chosen from the best skaters in each participating country, usually through preliminary national competitions. Speedskaters also compete on a World Cup circuit, which pits the world’s best skaters against one another during the year. A Figure Skating The major types of competitive figure skating are individual men’s and women’s competitions, pairs skating, ice dancing, and precision skating. In individualcompetitions a single skater performs requir...

• Badminton.

  Once play has started, players tend to hit straight, low-flying shots called drives. When the shuttle remains close to the center of the court, net shots can be a goodoption. Net shots can be hard-hit or delicate. They are aimed at the front area of the opponent’s court, forcing the opponent to play the shot close to the net. If the opponent manages to return a net shot, the return must be hit high to clear the net. This gives the player a chance for a smash—the deadliest attacking stroke inbadm...

• Manhattan Project - U.

  other possible uses of nuclear energy, such as using uranium to operate large power plants or, perhaps, as power sources for ships or submarines. Then Nazi Germanyinvaded Poland on September 1, 1939, and Europe plunged into war. The scientists realized that any plans to build large-scale nuclear power plants would have to waituntil the war was over. Two weeks after the invasion of Poland, Hitler made a radio speech in which he threatened Britain with “a weapon against which there is no defense.”...

• Fruit - biology.

  from a flower with several pistils. The ovary may have a single compartment, or carpel, which houses the ovule or ovules. Or the ovary may consist of two or morecarpels, each of which may contain one or more ovules. A drupe develops from an ovary with a single carpel and is characterized by an edible exocarp and mesocarp and an inedible, hard endocarp, or pit that encloses asingle seed. Cherries, peaches, apricots, and plums are examples of drupes. Almonds also are classified as drupes, but in a...

• Arithmetic I INTRODUCTION Arithmetic, branch of mathematics that arises from counting, the most basic mathematical operation.

  Subtract the units: 6 - 3 = 3. Then subtract the tens column: 6 – 2 = 4. The results of these two single-digit subtractions, written side by side, provide the answer: Subtraction is a bit more complicated if we need to subtract a larger digit from a smaller one. For example, when subtracting 47 from 92, the units value (7) of 47 isgreater than the units value (2) of 92. We can handle this situation using a procedure called borrowing, which is like carrying in reverse. Ten units can be borrowe...

• Obesity.

  of a day, contributing to the development of obesity. V TREATMENTS FOR OBESITY Obesity can become a chronic lifelong condition caused by overeating, physical inactivity, and even genetic makeup. No matter what the cause, however, obesity can beprevented or managed with a combination of diet, exercise, behavior modification, and in severe cases, weight-loss medications and surgery. A Diets The most common and conservative treatment for obesity utilizes a nutritionally balanced, low calorie diet...

• Michael Jordan.

  playoffs the Bulls pushed the Pistons to seven games in the Eastern Conference Finals before losing again. As he grew older, Jordan made a concerted effort to help his teammates reach their own potential. The result of his renewed commitment to team-oriented play was theBulls’ first NBA championship title. After the 1990-91 season the Bulls swept the Pistons in the Eastern Conference Finals and then defeated the Los Angeles Lakers inthe NBA Finals. Jordan won the league MVP award for the second...

• Michael Jordan I INTRODUCTION Michael Jordan, born in 1963, American professional basketball player, considered by many to be the greatest player in basketball history.

  playoffs the Bulls pushed the Pistons to seven games in the Eastern Conference Finals before losing again. As he grew older, Jordan made a concerted effort to help his teammates reach their own potential. The result of his renewed commitment to team-oriented play was theBulls’ first NBA championship title. After the 1990-91 season the Bulls swept the Pistons in the Eastern Conference Finals and then defeated the Los Angeles Lakers inthe NBA Finals. Jordan won the league MVP award for the second...

• Argentina Wins World Cup.

  Dutch team responded with two unanswered goals to earn the victory. In the consolation match Brazil squeaked past Italy, 2-1, in what was the final high-profileappearance of Brazilian star Roberto Rivelino, a three-time World Cup participant. The championship match was held at Río de la Plata stadium in Buenos Aires on Sunday, June 25. In a classic match-up, a methodical, disciplined European teamplayed against a spontaneous, mercurial South American squad. According to Argentina's coach, Ce...

• Babe Ruth's "Called Shot".

  When Ruth, the second New York batter in the fifth inning, came to the plate, Wrigley Field was roaring. “They called me ‘big belly’ and ‘baboon,’” Ruth recalled,according to the book Great Moments in American Sports by Jerry Brondfield. The New York Times said of the Chicago fans, “It seems decidedly unhealthy for anyone to taunt the great man Ruth too much, and very soon the crowd was to learn its lesson.” During the at bat, Ruth mouthed off to the Chicago players in thedugout as they and...

• Brain.

  The hypothalamus lies beneath the thalamus on the midline at the base of the brain. It regulates or is involved directly in the control of many of the body's vital drivesand activities, such as eating, drinking, temperature regulation, sleep, emotional behavior, and sexual activity. It also controls the function of internal body organs bymeans of the autonomic nervous system, interacts closely with the pituitary gland, and helps coordinate activities of the brain stem. D Brain Stem The brain st...

• Chemical Reaction - chemistry.

  Many groups of elements occur so often as ions that they are given names: nitrate, NO 3-; sulfate, SO 42-; and phosphate, PO 43-. The suffix -ate usually indicates the presence of oxygen. The positive ion, NH 4+, is called ammonium, as in NH 4Cl, ammonium chloride, or (NH 4)3PO4, ammonium phosphate. Rules for naming more complicated compounds exist, but many compounds have been given trivial names—for example, Na 2B4O7·10 H 2O, borax—or proprietary names—F(CF 2)nF, Teflon. These nonsystemat...

• 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,...

• Lewis and Clark Expedition.

  took a small detachment into present-day north central Montana, thinking that the course of the Marias River might provide an American claim to fur-rich country inwhat is now the Canadian province of Alberta. In August the groups reunited on the Missouri River, near the mouth of the Yellowstone. They arrived in St. Louis onSeptember 23, 1806. C Relations with the Native Americans and Spanish The Lewis and Clark Expedition made a journey through the homelands of native people. What American expl...

• Lewis and Clark Expedition - explorer.

  took a small detachment into present-day north central Montana, thinking that the course of the Marias River might provide an American claim to fur-rich country inwhat is now the Canadian province of Alberta. In August the groups reunited on the Missouri River, near the mouth of the Yellowstone. They arrived in St. Louis onSeptember 23, 1806. C Relations with the Native Americans and Spanish The Lewis and Clark Expedition made a journey through the homelands of native people. What American expl...

• Psychoanalysis.

  A cornerstone of modern psychoanalytic theory and practice is the concept of anxiety, which institutes appropriate mechanisms of defense against certain dangersituations. These danger situations, as described by Freud, are the fear of abandonment by or the loss of the loved one (the object), the risk of losing the object's love,the danger of retaliation and punishment, and, finally, the hazard of reproach by the superego. Thus, symptom formation, character and impulse disorders, andperversions,...

• Bowling.

  In each of the first nine frames the bowler rolls one or two balls. If the bowler knocks down all ten pins with the first ball, he or she has rolled a strike, the best roll possible. An X is recorded on the scoresheet or screen, and the bowler receives ten points (the number of pins knocked down) plus a bonus of the number of pins thebowler knocks down in his or her next two bowls. The maximum possible score in a strike frame, therefore, is 30: the strike followed by two more strikes on subseq...

• Classification - biology.

  species based on the fewest number of shared changes that have occurred from generation to generation. IV HISTORY OF CLASSIFICATION SYSTEMS Classification is one of the oldest sciences, but despite its age it is still a vigorous field full of new discoveries and methods. Much like other fields of science, greatthinkers have shaped the course of classification. One of the earliest classification schemes was established by Greek philosopher Aristotle, who lived in the 300s BC. Aristotle believe...

• Comparative Anatomy.

  In comparing two species, anatomists have to be careful to differentiate between homologous structures, which are ones that have evolved from a shared ancestor, andanalogous structures, which have developed from different origins. Homologous structures are built on the same underlying plan. A human arm, a bat’s wing, and awhale’s flipper look quite different from the outside, but the bones inside reveal that these limbs all have the same basic structure. Analogous structures, by contrast,often l...

• Neutron I INTRODUCTION Neutron, electrically neutral elementary particle that is part of the nucleus of the atom.

  Beta DecayBeta decay can occur in two ways. As shown on the left, a neutron turns into a proton by emitting an antineutrino and anegatively charged beta particle. As shown on the right, a proton turns into a neutron by emitting a neutrino and apositively charged beta particle. Positive beta particles are called positrons and negative beta particles are called electrons.After the decay, the nucleus of the atom contains either one less or one more proton. Beta decay changes an atom of oneelement i...

• 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...

• Lyndon B.

  A1 First Years in Office Johnson quickly made a two-fold reputation. He was a firm supporter of Roosevelt’s program, both domestic and foreign, and he was also a tireless worker on behalf ofthe voters he represented. Often the two activities coincided, as was the case when he helped to bring public power into Texas through the Rural ElectrificationAdministration and the Lower Colorado River Authority. He also secured funds for the building of dams, roads, and other public improvements in his di...

• Montréal - geography.

  percent), and Eastern Orthodox (2.8 percent) religions. Another 5.4 percent claim no religious affiliation. IV EDUCATION AND CULTURE Montréal has a large number of private schools, most of them partially funded by the province. Like the rest of Québec province, Montréal has two public schoolsystems, one for French speakers and one for English speakers. The Charter of the French Language (1977), known as Bill 101, restricts access to English-languageschools and requires children of immigrants t...

• Montréal - Geography.

  percent), and Eastern Orthodox (2.8 percent) religions. Another 5.4 percent claim no religious affiliation. IV EDUCATION AND CULTURE Montréal has a large number of private schools, most of them partially funded by the province. Like the rest of Québec province, Montréal has two public schoolsystems, one for French speakers and one for English speakers. The Charter of the French Language (1977), known as Bill 101, restricts access to English-languageschools and requires children of immigrants t...

• Gymnastics.

  harmoniously with the equipment to perform a graceful and error-free routine. There are also two team events in which five competitors perform together. At thehighest international levels, rhythmic gymnastics is judged on a 30-point scale rather than with the traditional 10-point scoring system. IV TRAMPOLINE Trampoline first appeared in the Olympics as a medal sport at the 2000 Games in Sydney, Australia, with a men’s individual event and a women’s individual event.Contestants bounce up and d...

• Hawaii (state) - geography.

  limestone along the coast. The volcanoes of the Hawaiian Islands are all so-called shield volcanoes, or lava domes. Unlike the volcanoes of Alaska and South America, those of Hawaii were notcreated by very explosive eruptions. Formed mostly by lava flows, they are great rounded mountain masses, rather than steep-sided cones. Mauna Kea, dormant forcenturies, is the highest mountain in the state. It rises to 4,205 m (13,796 ft) above sea level, and its summit is dotted with cinder cones formed by...

• Hawaii (state) - USA History.

  limestone along the coast. The volcanoes of the Hawaiian Islands are all so-called shield volcanoes, or lava domes. Unlike the volcanoes of Alaska and South America, those of Hawaii were notcreated by very explosive eruptions. Formed mostly by lava flows, they are great rounded mountain masses, rather than steep-sided cones. Mauna Kea, dormant forcenturies, is the highest mountain in the state. It rises to 4,205 m (13,796 ft) above sea level, and its summit is dotted with cinder cones formed by...

• Supreme Court of the United States.

  The Constitution does not specify formal qualifications for membership on the Supreme Court. From the beginning, though, justices have all been lawyers, and mostpursued legal and political careers before serving on the Court. Many justices served as members of Congress, governors, or members of the Cabinet. One president,William Howard Taft, was later appointed chief justice. Some justices came to the Court from private law practice, and others were appointed from positions as lawprofessors. Man...

• Uranus (planet) - astronomy.

  V COMPOSITION AND STRUCTURE A Interior of Uranus Uranus contains mostly rock and water, with hydrogen and helium (and trace amounts of methane) in its dense atmosphere. Astronomers believe that Uranus, likeNeptune, formed from the same material—principally frozen water and rock—that composes most of the planet’s moons. As the planet grew, pressures andtemperatures in the planet’s interior increased, heating the planet’s frozen water into a hot liquid. Uranus probably has a relatively small roc...

• Plant - biology.

  B1 Vacuoles Vacuoles are membrane-bound cavities filled with cell sap, which is made up mostly of water containing various dissolved sugars, salts, and other chemicals. B2 Plastids Plastids are types of organelles, structures that carry out specialized functions in the cell. Three kinds of plastids are important here. Chloroplasts contain chlorophyllsand carotenoid pigments; they are the site of photosynthesis, the process in which light energy from the sun is fixed as chemical energy in the b...

• Plate Tectonics.

  ridges. The Mid-Atlantic Ridge is an underwater mountain range created at a divergent plate boundary in the middle of the Atlantic Ocean. It is part of a worldwidesystem of ridges made by seafloor spreading. The Mid-Atlantic Ridge is currently spreading at a rate of 2.5 cm per year (1 in per year). The mid-ocean ridges today are60,000 km (about 40,000 mi) long, forming the largest continuous mountain chain on earth. Earthquakes, faults, underwater volcanic eruptions, and vents, oropenings, along...

• Djibouti (country) - country.

  l’Unité et de la Démocratie (FRUD; Front for the Renewal of Unity and Democracy) represents the Afar minority. The Parti National Démocratique (PND; Democratic National Party) and the Parti du Renouveau Démocratique (PRD; Democratic Renewal Party) are both small opposition parties favoring democratic reforms. VI HISTORY Djibouti lies at a major global crossroads where, some 100,000 years ago, early humans migrated from Africa to the Middle East. Livestock herding, which remainsimportant...

• Latin American Music I INTRODUCTION Tito Puente Playing the Drums Since the 1950s American drummer Tito Puente has popularized Latin American music, especially the mambo, in the United States.

  Panpipe Music of BoliviaWell before the Spanish conquest, native peoples such as the Quechua and Aymara living in the Andes Mountains inBolivia, Peru, and Ecuador, developed a rich musical tradition. Panpipes (set of tuned pipes), made of ceramic, sugarcane,or bone were paired with shell trumpets, cane flutes, and drums, which accompanied dancers during religious and secularceremonies. Large ensembles of 4 to 20 panpipe players are still the norm, and Spanish influences have since beenintegrated...

• Venus (planet) - astronomy.

  level winds circle the planet at 360 km/h (225 mph), making a complete rotation in only four days. These winds are said to super-rotate because they travel muchfaster than the rotation of the planet itself. These high-speed winds cover the planet completely, blowing toward the west at virtually every latitude from equator topole. The motions of descending probes, however, have shown that the bulk of Venus’s tremendously dense atmosphere, closer to the planet’s surface, is almoststagnant. From th...

• Electricity I INTRODUCTION Electricity, one of the basic forms of energy.

  electrons in the neutral object are attracted to the positive object. Some of these electrons flow to the side of the neutral object that is nearest to the positive object.This side of the neutral object accumulates electrons and becomes negatively charged. Because electrons leave the far side of the neutral object while its protonsremain stationary, that side becomes positively charged. Since the negatively charged side of the neutral object is closest to the positive object, the attraction bet...

• Perception (psychology).

  A4 Closure According to the law of closure, we prefer complete forms to incomplete forms. Thus, in the drawing below, we mentally close the gaps and perceive a picture of a duck. This tendency allows us to perceive whole objects from incomplete and imperfect forms. A5 Common Fate The law of common fate leads us to group together objects that move in the same direction. In the following illustration, imagine that three of the balls are moving in one direction, and two of the balls are mo...

• In-Line Skating.

  the foot using a combination of laces and buckles. Many skaters prefer a simple closure system that has laces on the lower portion of the skate and a buckle at the top.The boot liner is made of a soft, padded, cloth portion that fits inside the outer shell. Boot liners should be vented, which keeps the feet cool by allowing perspiration toescape during strenuous workouts or long trips. Attached to the bottom of each skate is the wheel frame. The frame houses from three to five wheels. The wheels...

• Chess.

  There are two standard methods of recording chess moves: the algebraic system and the descriptive system. In both systems, the pieces are designated by capitalinitials: K for king, Q for queen, R for rook, B for bishop, and N for knight. The initial P for pawn is used in the descriptive system only. Castling is noted as either 0-0(“short” castling on the king’s side) or 0-0-0 (“long” castling on the queen’s side). Each square is part of both a file and a rank, and in the algebraic system, that u...

• Basketball.

  rebound. Play continues as the teams score and possession changes. A time-out, when the game is stopped for a certain amount of time, allows coaches to instructplayers or to develop a new game strategy. A Offense Playing offense is perhaps the most prominent part of playing basketball, as it allows players to demonstrate and improve upon individual skills necessary to beingsuccessful. Many of basketball's best players have exceptional talents on offense. Basic offensive skills are passing, ball...

• Football.

  C Special Teams Each team has players who enter the game during special plays such as kickoffs, field goals, punts, and returns. The kicker kicks off at the beginning of a game or half,and after his team has scored. The kicker also scores points for the offensive team by kicking the ball through the goalpost’s vertical posts, also known as the uprights;these scores are called field goals. When the offensive team must surrender the ball to the opponents, a punter comes in to kick the ball downfi...

• Space Shuttle - astronomy.

  The two SRBs, with their combined thrust of some 26 million newtons (about 5.8 million lb), provide most of the power for the first two minutes of flight. The SRBs takethe space shuttle to an altitude of 45 km (28 mi) and a speed of 4,973 km/h (3,094 mph) before they separate and fall back into the ocean to be retrieved,refurbished, and prepared for another flight. After the boosters fall away, the three main engines continue to provide thrust. These engines are clustered at the rear end of the...

• Congress of the United States.

  senator, a person must be at least 30 years old, a citizen for nine years, and a resident of the state from which he or she is elected. Most members of Congress haveserved in state legislatures, city councils, or other elected bodies. See United States Senate: Campaigning for the Senate ; United States House of Representatives: Campaigning for the House. The 435 House seats are divided among the states in proportion to each state’s population. Every state is guaranteed at least one seat. State...

• Soccer.

  Two assistants, known as linesmen or referees’ assistants, aid the referee. Their primary job is to alert the referee when balls go out of the playing area and to assist inmaking offsides calls (see Rules section below). The assistants carry flags, which they wave when the ball leaves the playing area or use to point to the spot where a foul was committed. V EQUIPMENT Soccer is played with a round leather ball. It is between 68 and 71 cm (27 and 28 in) in circumference and weighs between 396...

• Messier Lifts the Curse.

  Swept up in the hype, the Rangers came out for game five at the Garden in a virtual sleepwalk. By the start of the third period they were down 3-0. New Yorkscratched back to level the score as Messier culminated the three-goal spurt with a wrist shot midway through the period. Vancouver then stunned the Rangers—andthe sellout crowd—by netting three quick goals to put the game far out of reach. Game six in Vancouver proved even more of a challenge for the Rangers. The team showed little will...

• Relativity - astronomy.

  beta, for example, might be as large as 0.5, and the mass of the electron doubled. The mass of a rapidly moving electron could be easily determined by measuring thecurvature produced in its path by a magnetic field; the heavier the electron, the greater its inertia and the less the curvature produced by a given strength of field ( see Magnetism). Experimentation dramatically confirmed Einstein's prediction; the electron increased in mass by exactly the amount he predicted. Thus, the kinetic ener...

• American Civil War.

  free state to keep the balance in the Senate. It also provided that slavery would be excluded from the still unorganized part of the Louisiana Territory. A line was drawnfrom Missouri’s southern boundary, at the latitude of 36°30’, and slavery would not be allowed in the territory north of that line,with the exception of Missouri. B Compromise of 1850 Agitation against slavery continued in the North. The South reacted by defending it ever more strongly. The Mexican War, by which the United Stat...

• American Civil War - U.

  free state to keep the balance in the Senate. It also provided that slavery would be excluded from the still unorganized part of the Louisiana Territory. A line was drawnfrom Missouri’s southern boundary, at the latitude of 36°30’, and slavery would not be allowed in the territory north of that line,with the exception of Missouri. B Compromise of 1850 Agitation against slavery continued in the North. The South reacted by defending it ever more strongly. The Mexican War, by which the United Stat...