37 résultats pour "displays"

• 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...

• 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...

• Museum.

  History museums are dedicated to promoting a greater appreciation and knowledge of history and its importance to understanding the present and anticipating thefuture. They range from historic sites and small historic house museums to large, encyclopedic institutions such as the Smithsonian’s National Museum of AmericanHistory in Washington, D.C. Many cities and states have historical societies that operate museums or historic sites. History museums usually collect a wide range ofobjects, includi...

• 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...

• 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,...

• Animal Courtship and Mating - biology.

  activity. These animals frequently copulate in water, and the penis helps transfer sperm before it is carried away by the currents Ostriches and rheas also contain apenis within the cloaca. Virtually all snakes and lizards display yet another variation of internal fertilization. Located in the tail are two penises, called hemepenes, which are covered by spinesand knobs that help lock it into place during mating. The male uses one hemepene at a time for copulation. Male salamanders secrete large...

• Antelope - biology.

  antelopes still display complex patterns of behavior, although much of it is instinctive rather than learned. In open habitats, antelopes run a high risk of predation (being preyed upon). To survive they use several kinds of defensive strategy, including living in herds. Herd living ensures that many pairs of eyes and ears are on the alert for danger. Herd living also gives individuals a better chance of avoiding attack, because predators canchoose from many potential targets. When danger thre...

• Paul Cézanne I INTRODUCTION Peaches and Pears Peaches and Pears (1888) by Paul Cézanne displays a sense of unity and continuity typical of the artist's many still-life paintings.

  the most transient natural effects as well as their own passing emotional states as the artists stood before nature. Under Pissarro's tutelage, and within a very shorttime during 1872-1873, Cézanne shifted from dark tones to bright hues and began to concentrate on scenes of farmland and rural villages. IV RETURN TO AIX-EN-PROVENCE Mont Sainte-Victoire by CézanneFrench artist Paul Cézanne painted Mont Sainte-Victoire, a mountain near his home in Provence in southern France, onmany occasions. Ov...

• Poseidon Greek Sea god and one of the Olympian gods; son of Cronus and Rhea; brother of Zeus, Hades, Demeter, Hera, and Hestia; husband The Roman goddess Pomona displays her fruits of plenty in the painting by French artist Nicholas Fouche (1653-1733).

• Dog Family - biology.

  muzzles, long and bushy tails, and large ears. Many foxes hunt by stalking prey and then leaping on it with a distinctive, stiff-legged pounce. Once thought to besolitary animals, foxes are now known to live in groups of up to six individuals. The remaining canids are each highly distinctive. Raccoon dogs and bush dogs are the least doglike canids in appearance. Raccoon dogs, found in eastern Asia, havestubby legs, a stout body, short ears, shaggy fur, and a black face mask that resembles a racc...

• 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...

• Mesopotamian Art and Architecture I INTRODUCTION Mesopotamian Art and Architecture, the arts and buildings of the ancient Middle Eastern civilizations that developed in the area (now Iraq) between the Tigris and Euphrates rivers from prehistory to the 6th century BC.

  arts. III EARLY DYNASTIC PERIOD Figures from Tell AsmarCreated around 2700 bc, these stone figures are from the city of Tell Asmar in what today is Iraq. From the Temple ofAbu, the statuettes stood in watchful prayer with the wide, staring eyes often found in Sumerian sculpture. The figuresare in the Iraq Museum, Baghdād, Iraq.Art Resource, NY The first historical epoch of Sumerian dominance lasted from about 3000 BC until about 2340 BC. While earlier architectural traditions continued, a ne...

• 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...

• Cell (biology) - biology.

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

• 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...

• Crafts.

  VI POTTERY Ceramic objects can be molded completely by hand or thrown (shaped) on a potter's wheel, a device with a rotating horizontal disk. When the clay hardens, it is fired ina high-temperature oven, or kiln, to strengthen it. To make the object waterproof, glazes may then be applied and the piece fired again. Although hand construction iseasy to master, throwing on the potter's wheel requires practice. Several simple tools are used by potters, including sponges, trimming tools, wooden sha...

• 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...

• Moscow (city, Russia) - geography.

  V RECREATION About 30 percent of Moscow’s territory is occupied by parks and public gardens, which were important elements of Soviet city planning. Gorky Park, which providesactivities such as amusement rides and boating, sits on the right bank of the Moscow River; the park’s display of a retired Soviet space shuttle dominates the riverside.The Moscow Zoo is located just west of the city center. The Botanical Gardens, administered by the Russian Academy of Sciences, offers a diverse display of...

• Dominican Republic - country.

  Manatees and sea turtles also live in Dominican waters. Common birds include blue herons, glossy ibis, flamingos, and brown pelicans. E Environmental Issues Urban dwellers of the Dominican Republic enjoy good access to safe water, but rural communities do not. While current water use is low relative to available resources,water shortages do occur. Although deforestation was once a serious problem in the Dominican Republic, by the beginning of the 21st century, the annual rate of deforestation h...

• Athens (Greece) - geography.

  At the heart of the modern city is Syntagma (Constitution) Square, located east of the Acropolis. The square is bordered by the national Parliament Building, originally aroyal palace completed in 1842 for King Otto I. Nearby is the Tomb of the Unknown Soldier, which features a daily changing of the guard. Several of the city’s principalhotels as well the offices of major banks and airline companies also face the square. Behind the Parliament Building is the National Gardens, a public park that i...

• Comet - astronomy.

  may exceed the planet Jupiter in size, however. Observations from telescopes on Earth and in space indicate that most of the gases in the coma and tail of a comet are fragmentary molecules, or radicals, of the mostcommon elements in space: hydrogen, carbon, nitrogen, and oxygen. The radicals, for example, of CH, NH, and OH may be broken away from the stable molecules CH 4 (methane), NH 3 (ammonia), and H 2O (water), which may exist as ices or more complex, very cold compounds in the nucleus. Al...

• 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...

• Killer Whale - biology.

  V REPRODUCTION Mating occurs more often among killer whales of different pods to avoid inbreeding within pods. About 16 to 18 months after mating, females give birth to a single calf.Newborn calves weigh about 200 kg (440 lb) and are about 2.5 m (8 ft) long. Mothers nurse their calf for 14 to 18 months, although mothers continue to be protectiveof their young long after the offspring have been weaned. Scientists do not know how long killer whales live in the wild. Scientists estimate that male...

• confess, I've never thought too much about giving lessons.

  unpopularity atschool, Grandma's coupons,storagefacilities, peoplewhodon't know whattheInternet is,bad handwriting, beautifulsongs,howthere won't behumans infifty years—" "Whosaidthere won't behumans infifty years?" Iasked her,"Are youanoptimist orapessimist?" Shelooked ather watch andsaid, "I'm optimistic. " "Then Ihave some badnews foryou, because humansaregoing todestroy eachother assoon asitbecomes easyenough to,which will bevery soon." "Whydobeautiful songsmakeyousad?" "Because theyaren't t...

• Air - chemistry.

  lighting systems, fertilizers, and semiconductors (substances used to make the chips in computers, calculators, televisions, microwave ovens, and many other electronicdevices). A Oxygen More than half of the oxygen produced in the United States is used by the steel industry, which injects the gas into basic oxygen furnaces to heat and produce steel(see Iron and Steel Manufacture: Basic Oxygen Process ). Metalworkers also combine oxygen with acetylene to produce high-temperature torch flames th...

• Eagle - biology.

  States, is a member of this group found only in North America. It is named for its snow-white head. However, the name bald does not refer to a lack of feathers but comes instead from an outdated word meaning marked with white, as in piebald. The adult bald eagle is blackish brown, with a white head and tail. Its bill, legs, and feet are bright yellow. The bill, which is longer and heavier than the gray bill of golden eagles, is useful for piercing the skin of fish. Bald eagles vary in size....

• Smithsonian Institution.

  F Arthur M. Sackler Gallery The Arthur M. Sackler Gallery houses a permanent collection of art from China, South and Southeast Asia, ancient and Islamic Iran, and Japan. Changing exhibitions ofAsian art are drawn from collections in the United States and abroad. The core of the collection was a gift from American research physician and medical publisherArthur M. Sackler. G Cooper-Hewitt, National Design Museum The Cooper-Hewitt is located in New York City and features examples of historical an...

• Acting I INTRODUCTION Lee Strasberg American acting teacher Lee Strasberg was best known for his association with the Actors Studio, of which he became the artistic director in 1951.

  truthfully felt those emotions at the moment they expressed them. Finding the true feeling in the proper place and time on stage, however, was a problem that Aristotleaddressed less well. He concluded that acting was an occupation for the gifted or insane. How to cross the artistic boundary beyond feigned emotions and flat imitation obsessed many Greek actors. In 315 BC the tragedian Polus carried the real ashes of his recently deceased son in an urn to stimulate a sense of genuine grief when h...

• Richard Wagner.

  which took place in August 1876. Wagner completed his final opera, Parsifal (which he called a 'festival drama of dedication' for the Festspielhaus), in 1882, and it premiered that July. In September Wagner moved to Venice, where in February 1883, after a heated argument with Cosima, he suffered a fatal heart attack. He was buried in Bayreuth. III MUSIC AND THOUGHT In the early 19th century, an opera was structured as a succession of conventional self-contained forms such as aria (a vocal so...

• 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...

• Portraiture I INTRODUCTION Portraiture, visual representation of individual people, distinguished by references to the subject's character, social position, wealth, or profession.

  CaracallaCaracalla is a Roman portrait bust in marble of the emperor Marcus Aurelius Antoninus, probably done circa ad 215. Theson of Septimius Severus, Caracalla (as he was known) was a brutal man whose qualities come through in this piece withits dramatic realism. The bust, which is now in the Louvre, Paris, evidently served as the inspiration for Michelangelo’sbust of Brutus more than one thousand years later.Bridgeman Art Library, London/New York The first representations of identifiable ind...

• White House - geography.

  Each Thanksgiving, the pardoning of the turkey takes place in the Rose Garden. This ceremony of rescuing a turkey and sending it to a petting zoo began during HarryTruman’s term, although Abraham Lincoln is said to have set a precedent by sparing his son’s pet turkey from the oven. III INSIDE THE WHITE HOUSE A large complex is needed for the many activities that take place at the White House. The White House has 132 rooms, 4 dining rooms, 35 bathrooms, 8 staircases, 3elevators, a clinic, a den...

• Amphibian (animal) - biology.

  strong enough to kill potential predators. C Hearing, Vision, and Vocalizations Amphibians rely on their senses to find food and evade predators. Amphibians lack external ears but have well-developed internal ears. Hearing is most acute in frogs,which typically have a middle ear cavity for transferring sound vibrations from the eardrum, or tympanum, to the inner ear. Frogs and toads also use their keen hearingin communicating with one another. Using a true voice box, or larynx, and a large, exp...

• Internet.

  usually pays a fixed monthly fee for a dedicated connection. In exchange, the company providing the connection agrees to relay data between the user’s computer andthe Internet. Dial-up is the least expensive access technology, but it is also the least convenient. To use dial-up access, a subscriber must have a telephone modem, a device thatconnects a computer to the telephone system and is capable of converting data into sounds and sounds back into data. The user’s ISP provides software that con...

• Pornography.

  censorship. Congress passed 20 obscenity laws between 1842 and 1956, most of which were variations of or amendments to the original Comstock Law. Later, Congress passed aseries of antipornography and anti-indecency laws dealing with new forms of technology and with the protection of children. The Protection of Children Against SexualExploitation Act of 1977 prohibits anyone from employing or inducing a minor to participate in sexual conduct or in the making of pornography. In 1988 Congresspassed...

• Berlin - geography.

  boroughs of Wedding and Tiergarten. Other important central areas include Kreuzberg and Friedrichshain, now united as the Friedrichshain-Kreuzberg borough, andPrenzlauer Berg, now incorporated as a part of the Pankow borough. Tiergarten contains a large wooded park, a zoo, and a variety of public monuments as well as the large, modern Congress Hall and the Reichstag building, which wasbuilt from 1884 to 1894. The Reichstag and the surrounding area have undergone renovation to accommodate the Bun...

• Lebanon (country) - country.

  during the civil war. Within the country, thousands of Shia Muslim refugees fled fighting in southern Lebanon in the 1990s and moved into shantytowns in Beirut’ssouthern suburbs. Lebanon’s major cities were greatly affected by the civil war. Beirut has gradually regained most of its prewar population and remains the country’s largest city. Tripoli,the northern port, is the second largest city. Jūniyah, north of Beirut, was developed as a wartime port and subsequently had a population boom. Za ḩl...