583 résultats pour "often"

• Arizona - geography.

  of the Mogollon Rim, the Little Colorado draws very little water from a relatively large watershed, usually containing a mere trickle of water in its riverbed. The ColoradoRiver’s principal tributary is the Gila River, which flows all the way across the southern part of the state from New Mexico to the California border. From the mountainsand plateaus of central Arizona, the Gila River receives the Salt, Agua Fria, and Hassayampa rivers. The Salt River is itself fed by the Verde River. The Gila...

• Arizona - USA History.

  of the Mogollon Rim, the Little Colorado draws very little water from a relatively large watershed, usually containing a mere trickle of water in its riverbed. The ColoradoRiver’s principal tributary is the Gila River, which flows all the way across the southern part of the state from New Mexico to the California border. From the mountainsand plateaus of central Arizona, the Gila River receives the Salt, Agua Fria, and Hassayampa rivers. The Salt River is itself fed by the Verde River. The Gila...

• Japanese Music I INTRODUCTION Shamisen Performance The shamisen is a Japanese instrument with three strings.

  utilizes six modes, or scales, of Chinese origin, all derived from two basic pentatonic (five-note) scales: ryo, D E-flat G A B-flat, plus F and C as auxiliary pitches; and ritsu, D F G A C, plus auxiliary pitches E-flat and B-flat. The meters in gagaku music are basically duple (in twos). IV DRAMATIC MUSIC Classical Nō Drama of JapanInspired both spiritually and artistically by Zen Buddhism, the Japanese n ō theater is composed of four main components:music (voices, instruments), choreogra...

• Easter.

  Many Easter traditions originated long before the beginning of the Christian era. Like Christmas, which is related to pre-Christian winter festivals, Easter is connected inmany ways with early pagan rituals that accompanied the arrival of spring. Easter is also associated with the Jewish festival of Passover. A Easter Eggs The Easter egg is associated with beliefs of particularly ancient origin. The egg was an important symbol in the mythologies of many early civilizations, including those ofIn...

• Suicide.

  C Sociological Theories Most social scientists believe that a society’s structure and values can influence suicide rates. French sociologist Émile Durkheim argued that suicide rates are related tosocial integration —that is, the degree to which an individual feels part of a larger group. Durkheim found suicide was more likely when a person lacked social bonds or had relationships disrupted through a sudden change in status, such as unemployment. As one example of the significance of social bond...

• Police.

  body. In larger agencies, executive officers may be selected through a civil service or merit system, after moving through the ranks from patrol officer to sergeant,lieutenant, captain, and (in still larger agencies) deputy or assistant chief. At the county level, the head of the agency usually holds the title sheriff. The sheriff is almost always elected and has the power to appoint deputies. Sheriffs'departments often provide law enforcement services for unincorporated areas of counties and ar...

• Water Pollution.

  Cryptosporidium in the water supply of Milwaukee, Wisconsin, sickened more than 400,000 people and killed more than 100. H Thermal Pollution Water is often drawn from rivers, lakes, or the ocean for use as a coolant in factories and power plants. The water is usually returned to the source warmer than when itwas taken. Even small temperature changes in a body of water can drive away the fish and other species that were originally present, and attract other species in placeof them. Thermal pol...

• Martin Luther King, Jr.

  disorder that local white officials would be forced to end segregation to restore normal business relations. The strategy did not work in Albany. During months ofprotests, Albany’s police chief jailed hundreds of demonstrators without visible police violence. Eventually the protesters’ energy, and the money to bail out protesters,ran out. The strategy did work, however, in Birmingham, Alabama, when SCLC joined a local protest during the spring of 1963. The protest was led by SCLC member FredShut...

• Martin Luther King, Jr.

  disorder that local white officials would be forced to end segregation to restore normal business relations. The strategy did not work in Albany. During months ofprotests, Albany’s police chief jailed hundreds of demonstrators without visible police violence. Eventually the protesters’ energy, and the money to bail out protesters,ran out. The strategy did work, however, in Birmingham, Alabama, when SCLC joined a local protest during the spring of 1963. The protest was led by SCLC member FredShut...

• Observatory - astronomy.

  Ultraviolet radiation, X rays, and gamma rays have shorter wavelengths than visible light has. These types of radiation tell astronomers about the hottest and mostviolent phenomena in the universe. Earth’s atmosphere blocks most of this radiation, so astronomers must send their observatories above the atmosphere aboardballoons, rockets, or satellites. Ultraviolet telescopes are much like visible light telescopes, but X-ray telescopes must have special nested cylindrical mirrors to prevent Xrays...

• Reconstruction (U.

  Instead, Congress began a lengthy debate over Reconstruction policy. The program eventually enacted resulted from a series of compromises among Republicanfactions; the Radicals were never powerful enough to gain everything they sought. Still, fueled by anger at the president's refusal to compromise and at the appearanceof former Confederates returning to power throughout the South, members of Congress moved increasingly toward the Radicals. The key Reconstruction measuresenacted aimed to produce...

• Turtle.

  Turtles use their jaws to cut and handle food. Instead of teeth, a turtle’s upper and lower jaws are covered by horny ridges, similar to a bird’s beak. Meat-eating turtlescommonly have knife-sharp ridges for slicing through their prey. Plant-eating turtles often have ridges with serrated edges that help them cut through tough plants.Turtles use their tongues in swallowing food, but unlike many other reptiles, such as chameleons, they cannot stick out their tongues to capture food. C Limb Structu...

• Turtle - biology.

  Turtles use their jaws to cut and handle food. Instead of teeth, a turtle’s upper and lower jaws are covered by horny ridges, similar to a bird’s beak. Meat-eating turtlescommonly have knife-sharp ridges for slicing through their prey. Plant-eating turtles often have ridges with serrated edges that help them cut through tough plants.Turtles use their tongues in swallowing food, but unlike many other reptiles, such as chameleons, they cannot stick out their tongues to capture food. C Limb Structu...

• Animal Behavior - biology.

  The first motor program analyzed in much detail was the egg-rolling response of geese. When a goose sees an egg outside its nest, it stares at the egg, stretches itsneck until its bill is just on the other side of the egg, and then gently rolls the egg back into the nest. At first glance this seems a thoughtful and intelligent piece ofbehavior, but it is a mechanical motor program; almost any smooth, rounded object (the sign stimulus) will release the response. Furthermore, removal of the egg on...

• Mythology.

  Across cultures, mythologies tend to describe similar characters. A common character is the trickster. The trickster is recklessly bold and even immoral, but through hisinventiveness he often helps human beings. In Greek mythology, Hermes (best known as the messenger of the gods) was a famous trickster. In one version of acharacteristic tale, Hermes, while still an infant, stole the cattle of his half-brother Apollo. To avoid leaving a trail that could be followed, Hermes made shoes from thebark...

• Temple (building) I INTRODUCTION Wat Phra Kaeo Thailand has nearly 18,000 Buddhist temples, called wats, throughout the country.

  colonnaded terraces connected by ramps. The surrounding area was planted with trees and flowers during Hatshepsut’sreign and for many years after.Gian Berto Vanni/Art Resource, NY In ancient Egypt, temples were grandiose, built of huge blocks and columns of stone. Often they were enlarged by successive rulers to form strung-out series of templeparts, as in the gigantic Temple of Amon (circa 1550-1070 BC) at Al Karnak. The Nile cliffs were used as settings for temples, such as the massive mortuar...

• Duck - biology.

  from water. When ducks feed they push their tongue against the top of their mouth to squeeze water through the lamellae, leaving the food behind. Mergansers arefish-eating ducks with slender bills that are notched on the edges like the blade of a saw. These saw-toothed beaks help the ducks catch and hold their slippery prey. VI COURTSHIP AND REPRODUCTION Ducks form pairs long enough to mate, but most species find new mates each year. In a few species, including buffleheads and whistling ducks,...

• Cobra (snake) - biology.

  Most cobras prey on small rodents or other small mammals. They also eat birds, snakes, lizards, frogs, toads, insects, and even eggs. Water cobras catch fish and kingcobras specialize in eating other snakes. Similar to other venomous snakes, cobras use venom to subdue their prey before swallowing it whole, generally head first. Thevenom may contain substances that also break down the prey for digestion. Despite their potent venom and dramatic threat displays, cobras are hunted and eaten by a num...

• Jaguar (animal) - biology.

  scientists have speculated that the jaguar’s robust canine teeth and enormously powerful bite developed specifically to pierce the armor of these reptiles. After killing a large animal, a jaguar will usually drag the carcass into dense cover before beginning to eat. If the kill is made in an open area, jaguars often drag theirprey for considerable distances. On one occasion, a jaguar killed a cow on the edge of a river and swam 790 m (2,600 ft) across the river carrying the cow. Unlike the other...

• Boxing.

  C Offensive Techniques To be effective, boxers must have an assortment of punches that are coordinated with their footwork. Less powerful punches often serve the important role of settingup the fighter’s chief “weapons,” as boxing analysts sometimes call a boxer’s main offensive skills. C1 Feinting Moving the hands or head to confuse an opponent is called feinting. A smart boxer will first test the opponent by trying different feints, noting the reaction to each onebefore deciding which will b...

• 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...

• Consciousness

  view faces several serious objections. Rival views of introspective consciousness fall into three categories, according to whether they treat introspective access (1) as epistemically looser or less direct than inner perception, (2) as tighter or more direct, or (3) as fundamentally non-epistemic or nonrepresentational. Theories in category (1) explain introspection as always retrospective, or as typically based on self-directed theoretical inferences. Rivals from category (2) maintain that an i...

• Eye. I INTRODUCTION Eye, light-sensitive organ of vision in animals. The eyes of

  Several structures, not parts of the eyeball, contribute to the protection of the eye. The most important of these are the eyelids, two folds of skin and tissue, upper andlower, that can be closed by means of muscles to form a protective covering over the eyeball against excessive light and mechanical injury. The eyelashes, a fringe ofshort hairs growing on the edge of either eyelid, act as a screen to keep dust particles and insects out of the eyes when the eyelids are partly closed. Inside the...

• Anthropology.

  humans, such as tools, pottery, and buildings) and human fossils (preserved bones). They also examine past environments to understand how natural forces, such as climate and available food, shaped the development of human culture. Some archaeologists study cultures that existed before the development of writing, a time knownas prehistory . The archaeological study of periods of human evolution up to the first development of agriculture, about 10,000 years ago, is also called paleoanthropology....

• Koala - biology.

  V REPRODUCTION Female koalas become sexually mature around 18 to 24 months of age. They can produce one offspring a year until they reach about 13 years of age. Males begin toproduce sperm around age 2 and, in the absence of older, stronger males, they may breed at that young age. More often, however, a male must grow big enough tocompete with other males for females, and mating generally begins for males at about 4 years of age. The breeding season for koalas is from October to May, during the...

• Political Parties in the United States.

  quickly enabled the Republican Party to overpower the Know-Nothings. Although the Republicans lost their first campaign for the presidency in 1856, they triumphed in1860 with former congressman Abraham Lincoln. The Republican victory resulted in part from the division of the Democratic Party into Northern and Southern factions,each of which ran its own presidential candidate, and in part from their success at attracting Whigs and Know-Nothings who had opposed the Republicans in 1856.During the C...

• Skin. I INTRODUCTION Skin, outer body covering of an animal. The term skin

  III SKIN APPENDAGES In humans, the skin appendages, or structures embedded in the skin, include hair, nails, and several types of glands. Glands are groups of cells that produce andsecrete substances needed by other parts of the body. In other vertebrates, the skin appendages include scales (in fish and reptiles) and feathers (in birds). Together,the skin and the skin appendages are known as the integumentary system of the body. A Hair Hair is a distinguishing characteristic of mammals, a gro...

• 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...

• Flower - biology.

  insects. The sepals unfurl as the flower opens and often resemble small green leaves at the flower’s base. In some flowers, the sepals are colorful and work with thepetals to attract pollinators. E Variations in Structure Like virtually all forms in nature, flowers display many variations in their structure. Most flowers have all four whorls—pistil, stamens, petals, and sepals. Botanists callthese complete flowers. But some flowers are incomplete, meaning they lack one or more whorls. Incomplet...

• American Literature: Poetry I INTRODUCTION Phyllis McGinley American poet and author Phyllis McGinley composed light, witty verse, much of which deals with family life.

  Taylor, a poet of great technical skill, wrote powerful meditative poems in which he tested himself morally and sought to identify and root out sinful tendencies. In“God's Determinations Touching His Elect” (written 1680?), one of Taylor’s most important works, he celebrates God's power in the triumph of good over evil in thehuman soul. All of Taylor’s poetry and much of Bradstreet’s served generally personal ends, and their audience often consisted of themselves and their family andclosest frie...

• Rocket.

  the vacuum of space, however, demonstrated that this belief was not true. In fact, rockets produce more thrust in the vacuum of space than on Earth. Air pressure andfriction with the air reduce a rocket’s thrust by about 10 percent on Earth as compared to the rocket’s performance in space. B Thrust and Efficiency Thrust is a measurement of the force of a rocket, or the amount of “push” exerted backward to move a rocket forward. Thrusts vary greatly from rocket to rocket.Engineers measure thrust...

• Rocket - astronomy.

  the vacuum of space, however, demonstrated that this belief was not true. In fact, rockets produce more thrust in the vacuum of space than on Earth. Air pressure andfriction with the air reduce a rocket’s thrust by about 10 percent on Earth as compared to the rocket’s performance in space. B Thrust and Efficiency Thrust is a measurement of the force of a rocket, or the amount of “push” exerted backward to move a rocket forward. Thrusts vary greatly from rocket to rocket.Engineers measure thrust...

• Music I INTRODUCTION World Music Tour Click on the instruments to hear music from around the world.

  Duke EllingtonAmerican composer, bandleader, and pianist Duke Ellington endures as perhaps the most important pioneer in big-bandjazz. Ellington and his orchestra shared a special interdependent relationship: Using the band as his musical workshop,Ellington derived his orchestra’s tone coloring from the unique sound qualities of the group’s individual players. Thisparticular style was later dubbed the “Ellington Effect” by jazz arranger Billy Strayhorn, who also wrote one of the band’ssignature...

• Theater I INTRODUCTION The Art of Theater BBC Worldwide Americas, Inc.

  Theater at EpidaurusAncient Greek dramas were performed in open-air theaters like this one in Epidaurus, Greece, which was designed byPolyclitus the Younger in 350 bc. A festival of ancient Greek drama is still held in the summer in this 14,000-seat theater.Roger Wood/Corbis Fundamental to the theater experience is the act of seeing and being seen; in fact, the word theater comes from the Greek word theatron , meaning 'seeing place.' Throughout the history of world cultures, actors have used...

• Library (institution).

  rooms, special galleries for exhibitions, auditoriums for lectures or concerts, computer rooms, children’s rooms, photocopy rooms, and classrooms. A3 Lending Materials As part of their mission to provide information resources to the community, public libraries allow users to borrow items from their collections for limited amounts of time.To be eligible to borrow public library materials, a user must register her or his name, address, and other basic information with the local library’s circulat...

• Criminal Law.

  for rehabilitative treatment for the offender. On the other hand, the goals of punishment may at times conflict. The retributive and deterrence theories call for theinfliction of unpleasant experiences upon the criminal, including harsh prison treatment; but the prison environment may not be conducive to, or may even defeat,rehabilitation. No one theory of punishment addresses all the goals of criminal law. A combination of theories and goals plays a part in the thinking of the legislators who e...

• Holy Roman Empire I INTRODUCTION Holy Roman Empire, political entity of lands in western and central Europe, founded by Charlemagne in AD 800 and dissolved by Emperor Francis II in 1806.

  acquired the imperial title and an area running from the North Sea through Lotharingia (Lorraine) and Burgundy to northern Italy; Louis II received East Francia (theGerman duchies of Saxony, Swabia, and Bavaria). In 870 Lothair’s middle kingdom was divided by the Treaty of Mersen, which gave Lotharingia to East Francia and therest to West Francia. This division created the foundation for today’s states of Germany and France, respectively; however, in the 9th century these were highly fractured d...

• Holy Roman Empire .

  acquired the imperial title and an area running from the North Sea through Lotharingia (Lorraine) and Burgundy to northern Italy; Louis II received East Francia (theGerman duchies of Saxony, Swabia, and Bavaria). In 870 Lothair’s middle kingdom was divided by the Treaty of Mersen, which gave Lotharingia to East Francia and therest to West Francia. This division created the foundation for today’s states of Germany and France, respectively; however, in the 9th century these were highly fractured d...

• William Shakespeare I INTRODUCTION William Shakespeare English playwright and poet William Shakespeare, who lived in the late 1500s and early 1600s, is regarded as the greatest dramatist in the history of English literature.

  Avon, Warwickshire, a prosperous town in the English Midlands. Based on this record and on the fact that children in Shakespeare’s time were usually baptized two orthree days after birth, April 23 has traditionally been accepted as his date of birth. The third of eight children, William Shakespeare was the eldest son of John Shakespeare, a locally prominent glovemaker and wool merchant, and Mary Arden, thedaughter of a well-to-do landowner in the nearby village of Wilmcote. The young Shakespeare...

• Medicine.

  C Other Health Professionals Medicine is not restricted to physicians. A wide variety of health care practitioners work in this exciting field. By far the largest professional group is nurses. Registerednurses help physicians during examinations, treatment, and surgery. They observe, evaluate, and record patients’ symptoms, administer medications, and provideother care ( see Nursing). Nurse practitioners perform basic duties once reserved for physicians, such as diagnosing and treating common i...

• Abraham Lincoln I INTRODUCTION Abraham Lincoln (1809-1865), 16th president of the United States (1861-1865) and one of the great leaders in American history.

  fence in 4 hectares (10 acres) to grow corn. Then he hired out to neighbors, helping them to split rails. That year, Lincoln attended a political rally and was persuaded tospeak on behalf of a local candidate. It was his first political speech. A witness recalled that Lincoln “was frightened but got warmed up and made the best speech of theday.” In 1831 Lincoln made a second trip to New Orleans. He was hired, along with his stepbrother and a cousin, by Denton Offutt, a Kentucky trader and specul...

• Abraham Lincoln.

  fence in 4 hectares (10 acres) to grow corn. Then he hired out to neighbors, helping them to split rails. That year, Lincoln attended a political rally and was persuaded tospeak on behalf of a local candidate. It was his first political speech. A witness recalled that Lincoln “was frightened but got warmed up and made the best speech of theday.” In 1831 Lincoln made a second trip to New Orleans. He was hired, along with his stepbrother and a cousin, by Denton Offutt, a Kentucky trader and specul...

• Abraham Lincoln

  fence in 4 hectares (10 acres) to grow corn. Then he hired out to neighbors, helping them to split rails. That year, Lincoln attended a political rally and was persuaded tospeak on behalf of a local candidate. It was his first political speech. A witness recalled that Lincoln “was frightened but got warmed up and made the best speech of theday.” In 1831 Lincoln made a second trip to New Orleans. He was hired, along with his stepbrother and a cousin, by Denton Offutt, a Kentucky trader and specul...

• Abraham Lincoln - USA History.

  fence in 4 hectares (10 acres) to grow corn. Then he hired out to neighbors, helping them to split rails. That year, Lincoln attended a political rally and was persuaded tospeak on behalf of a local candidate. It was his first political speech. A witness recalled that Lincoln “was frightened but got warmed up and made the best speech of theday.” In 1831 Lincoln made a second trip to New Orleans. He was hired, along with his stepbrother and a cousin, by Denton Offutt, a Kentucky trader and specul...

• Colleges and Universities.

  and (3) large universities that include undergraduate programs in addition to graduate and professional schools. D Graduate and Professional Schools Professional schools are typically divisions of large universities. They offer specialized education in a variety of professional fields, such as education, business, medicine,law, social work, agriculture, journalism, architecture, fine arts, nursing, engineering, and music. Some professional schools offer four- or five-year programs leading toa b...

• Japan - country.

  island’s fertile soils support agriculture and provide the vast majority of Japan’s pasturelands. In addition, Hokkaidō contains coal deposits, and the cold currents off itsshores supply cold-water fish. Winters are long and harsh, so most of Hokkaid ō is lightly settled, housing about 5 percent of Japan’s population on approximately 20 percent of its land area. However,its snowy winters and unspoiled natural beauty attract many skiers and tourists. Hokkaid ō is thought of as Japan’s northern fr...

• 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...

• Western Music I INTRODUCTION Bizet's Carmen Georges Bizet's Carmen, first performed in Paris in 1875, was a milestone in the history of French opera.

  church ceremonies during the period from the 5th to the 7th century. Roman chant became known as Gregorian chant after Pope Gregory I, the Great, who may havecomposed some of the melodies and who actively encouraged an orderly, ritualized use of music by the church. Because Gregory and later popes preferred Gregorianchant to the varieties that had developed elsewhere in Europe, Gregorian chant eventually superseded most of the others. Gregorian and other chant styles arepreserved in many manuscr...

• Native American Architecture.

  B Relationship to the Universe and Nature A more profound difference between European American and Native American perceptions lay in how human beings saw themselves in relationship to the universe andin what they believed their responsibilities were to the natural world and to each other. Most European Americans saw themselves as separate from creation andadversaries of nature, ever struggling to conquer and subdue nature and force it to yield to their will. Native Americans saw themselves as...

• Native American Architecture I INTRODUCTION Native American Architecture, traditional architecture of the peoples of who lived in North America before Europeans arrived.

  Mound Builders who resided in the area.John Elk III/Bruce Coleman, Inc. Another mound building culture, named Hopewell, also appears to have originated in Ohio but expanded west to Iowa, Kansas, and Oklahoma, south to Louisiana,Mississippi, and Alabama, east to Georgia and the Appalachian Mountains, and north to Wisconsin, Michigan, and lower Ontario in Canada. The Hopewell culture lastedfrom about 200 BC to 400 AD. Hopewell people built large, linear mounds to create enclosures in geometrical...