230 résultats pour "single"

• World Wide Web.

  browser does not display the URL for the user. Instead, to indicate that an item is selectable, the browser changes the color of the item on the screen and keeps theURL associated with the link hidden. When a user clicks on an item that corresponds to a selectable link, the browser consults the hidden information to find theappropriate URL, which the browser then follows to the selected page. Because a link can point to any page in the Web, the links are known as hyperlinks. See also Hypermedia...

• 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...

• The Summer Games of 1992 - sport.

  In the most ambitious undertaking of all, a stretch of rundown warehouses and abandoned factories beside the long-neglected Mediterranean waterfront wastransformed into a sparkling new district of apartments, shopping areas, and palmetto-lined promenades. During the games, the area served as the Olympic athletes'village, where, for the first time at any games, organizers offered accommodations to competitors and their coaches free of charge. After the games the apartmentswere to be sold to help...

• Blood.

  substances. For example, a person who is blood type A positive will not make antibodies against the A or Rh markers, but will make antibodies against the B marker,which is not on that person’s own red blood cells. If blood containing the B marker (from types B positive, B negative, AB positive, or AB negative) is transfused into thisperson, then the transfused red blood cells will be rapidly destroyed by the patient’s anti-B antibodies. In this case, the transfusion will do the patient no good a...

• 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...

• Horse Racing.

  interested parties claim the same horse at the same price, lots are drawn to determine the winning offer. Knowledgeable owners and trainers may use claiming races toobtain, at bargain prices, horses whose former owners underestimated the potential of their animals. Two other types of contests are match races and walkovers. A match race pits only two horses, almost always that season’s most successful racers, in a head-to-headduel. A walkover occurs when only one horse has not been scratched (w...

• Trinidad and Tobago - country.

  III PEOPLE The history of Trinidad and Tobago is reflected in the makeup of its population, among the most ethnically diverse in the Caribbean. Blacks of African ancestry andAsians of Indian ancestry each make up about 40 percent of the population. The remainder is mainly of mixed ancestry, although there are also small groups of peopleof Chinese, European, South American, and Middle Eastern descent. The ethnic diversity of Trinidad and Tobago owes its origins to slavery and its abolition. Afr...

• French Revolution.

  B2 Assembly of Notables and Estates-General To pressure the parlements into accepting the plan, Calonne decided to gain prior approval of it from an Assembly of Notables—a group of hand-picked dignitaries hethought would sympathize with his views. But Calonne had badly miscalculated. Meeting in January 1787, the assembly refused to believe that a financial crisis reallyexisted. They had been influenced by Necker’s argument that state finances were sound and suspected that the monarchy was only...

• French Revolution .

  B2 Assembly of Notables and Estates-General To pressure the parlements into accepting the plan, Calonne decided to gain prior approval of it from an Assembly of Notables—a group of hand-picked dignitaries hethought would sympathize with his views. But Calonne had badly miscalculated. Meeting in January 1787, the assembly refused to believe that a financial crisis reallyexisted. They had been influenced by Necker’s argument that state finances were sound and suspected that the monarchy was only...

• Spain - country.

  B Natural Resources Spain has a number of mineral resources. The largest known deposits are of iron ore, zinc, and lead. Spain also produces significant quantities of copper and mercury.These deposits are mined mainly in Huelva province in southwestern Spain, around Cartagena on the Mediterranean, and at various points along the Bay of Biscay inthe north. Additionally, uranium is mined in the region of Extremadura, near the Portuguese frontier, where pyrites, fluorspar, gypsum, tungsten, and po...

• Ancient Rome .

  attributed to Numa, including the selection of virgins to be priestesses of the goddess Vesta. He also established a calendar to differentiate between normal workingdays and those festival days sacred to the gods on which no state business was allowed. His peaceful reign lasted from 715 to 673 BC. Under Tullus Hostilius (672–641 BC) the Romans waged an aggressive foreign policy and began to expand their lands by the conquest of nearby cities like Alba Longa. When the warlike King Hostilius co...

• Ancient Rome - USA History.

  attributed to Numa, including the selection of virgins to be priestesses of the goddess Vesta. He also established a calendar to differentiate between normal workingdays and those festival days sacred to the gods on which no state business was allowed. His peaceful reign lasted from 715 to 673 BC. Under Tullus Hostilius (672–641 BC) the Romans waged an aggressive foreign policy and began to expand their lands by the conquest of nearby cities like Alba Longa. When the warlike King Hostilius co...

• Federal Republic of Germany - country.

  B Rivers and Lakes Rivers have played a major role in Germany’s economic development. The Rhine River flows in a northwesterly direction from Switzerland through much of westernGermany and The Netherlands into the North Sea. It is a major European waterway and a pillar of commerce and trade. Its primary German tributaries include theMain, Mosel, Neckar, and Ruhr rivers. The Oder (Odra) River, along the border between Poland and Germany, runs northward and empties into the Baltic; it provides an...

• 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...

• 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...

• Tragedy I INTRODUCTION Euripides Unlike other 5th-century BC Greek playwrights, tragic poet Euripides addressed the plight of the common people, rather than that of mythic heroes.

  SenecaSeneca was a Roman philosopher, dramatist, and statesman. His tragedies later influenced Renaissance dramatists,including William Shakespeare. The bust of Seneca shown here is a Roman copy of a Greek original.Art Resource, NY Aeschylus is one of the best known of the ancient Greek tragic playwrights. The author of some 90 plays, he established many of the conventions of the tragic dramaticform, which he perfected throughout his career. Aeschylus's skillful use of poetic language and brilli...

• Computer.

  which can activate computer commands in conjunction with voice recognition software. “Tablet” computers are being developed that will allow users to interact with theirscreens using a penlike device. E The Central Processing Unit Information from an input device or from the computer’s memory is communicated via the bus to the central processing unit (CPU), which is the part of the computerthat translates commands and runs programs. The CPU is a microprocessor chip—that is, a single piece of sil...

• 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...

• 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...

• Bacteria - biology.

  A2 b Bacterial Killers Some dramatic infectious diseases result from exposure to bacteria that are not part of our normal bacterial community. Cholera, one of the world’s deadliest diseasestoday, is caused by the bacterium Vibrio cholerae . Cholera is spread in water and food contaminated with the bacteria, and by people who have the disease. After entering the body, the cholera bacteria grow in the intestines, often along the surface of the intestinal wall, where they secrete a toxin (poiso...

• Eukaryote - biology.

  The waste is then expelled through a hole in the fused membrane. In complex animals, cells generate wastes such as urea when nutrients are broken down within cells.These wastes are transported by blood to the kidneys. The kidneys process the waste and produce urine, which is removed from the body through the bladder.Undigested food travels through the tubelike intestines and is eliminated through the digestive system. V EVOLUTIONARY ORIGINS Eukaryotes evolved much later than prokaryotes, whose...

• Country Music I INTRODUCTION Willie Nelson Country singer and musician Willie Nelson gained national popularity during the 1970s for a string of country hits, including the 1978 hits "Mammas Don't Let Your Babies Grow Up to Be Cowboys" and "Georgia On My Mind.

  Singer and mandolin player Bill Monroe is known as the father of bluegrass music. A virtuoso mandolin player, Monroe combined traditional folk ballads and gospel songswith string-band music played at very fast tempos. Monroe, with his band The Blue Grass Boys, performed from the mid-1920s until Monroe’s death in 1996. Otherwell-known bluegrass performers include banjo player Earl Scruggs, who played with Monroe during the 1940s; the Osborne Brothers, a duo from Kentucky known forits work during...

• Religion.

  By the end of the 19th century, scholars were making religion an object of systematic inquiry. Müller’s comparative approach was adopted in many European andJapanese universities, and as a result the common features of world religions (such as gods, prayer, priesthood, and creation myths) were the subjects of sustainedscholarly investigation. In addition, field anthropologists had begun to compile firsthand accounts of the religions of peoples who previously had been dismissed assavages. The stu...

• Radar.

  gathers the weak returning radar signals and converts them into an electric current. Because a radar antenna may both transmit and receive signals, the duplexerdetermines whether the antenna is connected to the receiver or the transmitter. The receiver determines whether the signal should be reported and often does furtheranalysis before sending the results to the display. The display conveys the results to the human operator through a visual display or an audible signal. B1 The Antenna The rec...

• Television.

  A charge-coupled device (CCD) can be much smaller than a camera tube and is much more durable. As a result, cameras with CCDs are more compact and portablethan those using a camera tube. The image they create is less vulnerable to distortion and is therefore clearer. In a CCD, the light from a scene strikes an array ofphotodiodes arranged on a silicon chip. Photodiodes are devices that conduct electricity when they are struck by light; they send this electricity to tiny capacitors. Thecapacitors...

• Culture.

  form of knowledge, such as scientific discoveries; objects, such as works of art; and traditions, such as the observance of holidays. C1 Ethnocentrism and Cultural Relativism Self-identity usually depends on culture to such a great extent that immersion in a very different culture—with which a person does not share common ways of life orbeliefs—can cause a feeling of confusion and disorientation. Anthropologists refer to this phenomenon as culture shock. In multicultural societies —societies s...

• Modern Art I INTRODUCTION American Gothic American Gothic was painted by the 20th-century American artist Grant Wood in 1930.

  while at the other side a woman in black appears to mourn the end of her participation in the dance. Click on the buttonsto learn more.© Microsoft Corporation. All Rights Reserved. In view of this diversity, it is difficult to define modern art in a way that includes all of 20th-century Western art. For some critics, the most important characteristic ofmodern art is its attempt to make painting and sculpture ends in themselves, thus distinguishing modernism from earlier forms of art that had con...

• 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...

• Maine - geography.

  temperatures range from 17° to 21°C (62° to 70°F) with the southern interior being the warmest and the east coast and north the coolest. However, daytime summertemperatures may reach the lower 30°s C (lower 90°s F), and temperatures in winter have fallen as low as -44°C (-48°F) in the interior. D2 Precipitation Precipitation (rainfall and snowfall) in Maine is evenly distributed throughout the year. Most areas receive from 860 to 1,020 mm (34 to 40 in) yearly, although parts ofthe coast are som...

• Maine - USA History.

  temperatures range from 17° to 21°C (62° to 70°F) with the southern interior being the warmest and the east coast and north the coolest. However, daytime summertemperatures may reach the lower 30°s C (lower 90°s F), and temperatures in winter have fallen as low as -44°C (-48°F) in the interior. D2 Precipitation Precipitation (rainfall and snowfall) in Maine is evenly distributed throughout the year. Most areas receive from 860 to 1,020 mm (34 to 40 in) yearly, although parts ofthe coast are som...

• New York (city) - geography.

  The Bronx is the fourth largest and the northernmost of the five boroughs, and the only one on the American mainland. Even so, it is surrounded by water on threesides: Long Island Sound on the east, the Harlem and East rivers on the south, and Hudson River on the west. Encompassing 109 sq km (42 sq mi), it had 1,332,650inhabitants in 2000. Largely residential, the Bronx includes dozens of vibrant neighborhoods. Fieldston is particularly elegant, with great stone houses set among spacious lawns a...

• Switzerland - country.

  formation over higher elevations. The wind reverses direction about sundown and moves down the valley as a cool downdraft. The foehn, which occurs during the wintermonths, is a dry and relatively warm airflow that is drawn northward over the Alps. The foehn can quickly melt snow and ice, increasing the risk of mudslides andavalanches. D Natural Resources Waterpower is the chief natural resource of Switzerland. The principal source of water is runoff from the considerable annual precipitation th...

• Thailand - country.

  E Natural Resources Thailand possesses a range of mineral resources. Tin is mined in the peninsula. Important gemstones, such as sapphires, are found in the southeast, and coal reserves,particularly lignite, are in the north. Fish are abundant in rivers and coastal waters. In addition to being consumed domestically, fish are also exported. F Climate Thailand experiences a typical monsoon climate. Winds blow from the northeast during the winter months of October to March or April (known as the...

• Fondements historiques du droit constitutionnel britannique TD

  constitution, it retains sufficient flexibility to allow adaptation to suit the changing circumstances of society with minimum procedural restraints. Codified/uncodified are better description than written/unwritten to better distinguish the UK constitution from that of other countries because most of the UK constitution is written but has never been codified into one single document. Yet flexibility should not be unrestrained, that is to say an ability to evolve can be constrained by existi...

• House (architecture) I INTRODUCTION Trulli in Alberobello, Italy Alberobello, in the Apulia region of southeastern Italy, is noted for its unusual limestone houses known as trulli (from Greek trullos, dome).

  Fresco in the Villa of the Mysteries, PompeiiThe Villa of the Mysteries, Pompeii, Italy (built about 50 bc), featured a large hall with this mural encircling it. The mural ispainted in the Second Style of Roman painting. (Historians of art recognize four periods or styles in Roman wall painting.)The mural in the Villa of the Mysteries is thought to depict the initiation rituals of a mystery religion. For this reason, it hasbeen conjectured that the hall was used for cult rituals.Bridgeman Art Li...

• 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...

• 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...

• Rock Music I INTRODUCTION Carlos Santana Mexican-born guitarist Carlos Santana became a superstar in the late 1960s with a string of hits and an appearance at the famous Woodstock rock festival in 1969.

  point (a single pitch sustained through a progression of chords), and the parallel movement of chords, derived from a technique on the electric guitar known as bar-chording. Many elements of African American music have been a continuing source of influence on rock music. These characteristics include riffs (repeated patterns), backbeats (emphasizing the second and fourth beats of each measure; see Musical Rhythm: Pulse and Meter ), call-and-response patterns, blue notes (the use of certain...

• 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...

• Iranian Art and Architecture I INTRODUCTION Iranian Art and Architecture, the visual arts of Iran.

  The first great development of ancient Persian architecture took place under the Achaemenid dynasty during the Persian Empire, from about 550 to 330 BC. Remains of Achaemenian architecture are numerous, the earliest being ruins at Pasargadae, the capital city of Cyrus the Great. These ruins include two palaces, a sacred precinct, acitadel, a tower, and the tomb of Cyrus. The palaces were set in walled gardens and contained central columnar halls, the largest of which was 37 m (111 ft) in length...

• Lithuania - country.

  pollution. III PEOPLE Ethnic Lithuanians constitute about 80 percent of the country’s population. The proportion of Lithuanians increased slightly in the first years after the dissolution of theSoviet Union—many Lithuanians returned to their homeland from that country and abroad while some Russians, Ukrainians, and Belarusians left the country. Russiansand Poles constitute the country’s largest minority groups, each accounting for roughly 7 percent of the population. Jews were the largest mino...

• Industrial Revolution I INTRODUCTION Industrial Revolution, widespread replacement of manual labor by machines that began in Britain in the 18th century and is still continuing in some parts of the world.

  The most important advance in iron production occurred in 1784 when Englishman Henry Cort invented new techniques for rolling raw iron, a finishing process thatshapes iron into the desired size and form. These advances in metalworking were an important part of industrialization. They enabled iron, which was relativelyinexpensive and abundant, to be used in many new ways, such as building heavy machinery. Iron was well suited for heavy machinery because of its strength anddurability. Because of t...

• Industrial Revolution .

  The most important advance in iron production occurred in 1784 when Englishman Henry Cort invented new techniques for rolling raw iron, a finishing process thatshapes iron into the desired size and form. These advances in metalworking were an important part of industrialization. They enabled iron, which was relativelyinexpensive and abundant, to be used in many new ways, such as building heavy machinery. Iron was well suited for heavy machinery because of its strength anddurability. Because of t...

• Judaism.

  is learned or memorized”), the earliest document of rabbinic literature, edited in Palestine at the turn of the 3rd century. Subsequent rabbinic study of the Mishnah inPalestine and Babylonia generated two Talmuds (“that which is studied”; also called Gemera, an Aramaic term with the same meaning; see Talmud), wide-ranging commentaries on the Mishnah. The Babylonian Talmud, edited about the 6th century, became the foundation document of rabbinic Judaism. Early rabbinic writings also include exe...

• American Westward Movement - U.

  British expansion. However, Native Americans of the Great Lakes and Ohio Valley lashed out against the English in an attempt to preserve their independence, theirland, and their way of life. With the Ottawa chief Pontiac as their most visible leader, the tribes waged a bloody and costly war. As a result, the British governmentdecided to keep the white settlers apart from the Native Americans. It issued the Royal Proclamation of 1763, banning all white settlement beyond the Appalachians andstatin...

• Kenya - country.

  threatens fish and other water life in the lake by depriving them of oxygen. Kenya is well known for its game parks—including Masai Mara Game Park and Tsavo National Park in the south, and Marsabit National Reserve in the north—whichattract large numbers of tourists and much revenue. Conservation of wildlife within reserves has thus received high priority. About 13 percent (2007) of Kenya’s totalland is protected. There are 229 (2004) threatened species in Kenya. Threatened habitats include the...

• Psychotherapy.

  Other managed-care companies pay therapists a set fee to meet with a client for up to a specified maximum number of sessions depending on the nature of theproblem, free of interference from case reviewers. For example, a managed-care firm may pay a therapist $200 to hold up to eight sessions with a person. If the clientuses all eight sessions, the therapist normally loses money. But if treatment stops after two or three sessions, the therapist makes a profit. This relatively new system iscontrov...

• Intelligence.

  education. Teachers had no way of knowing which of the “slow” students had true learning problems and which simply had behavioral problems or poor prior education.In 1904 the French Ministry of Public Instruction asked Binet and others to develop a method to objectively identify children who would have difficulty with formaleducation. Objectivity was important so that conclusions about a child’s potential for learning would not be influenced by any biases of the examiner. The governmenthoped tha...

• 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...