683 résultats pour "used"

• Drug. I INTRODUCTION Drug, substance that affects the function of living cells, used

  normalizing chemical activity in the emotional centers of the brain. Antianxiety drugs, also referred to as tranquilizers, treat anxiety by decreasing the activity in theanxiety centers of the brain. Sedative-hypnotic drugs are used both as sedatives to reduce anxiety and as hypnotics to induce sleep. Sedative-hypnotic drugs act by reducing brain-cell activity.Stimulant drugs, on the other hand, increase neuronal (nerve cell) activity and reduce fatigue and appetite. Analgesic drugs reduce pain...

• Ship. I INTRODUCTION Ship, vessel that is buoyant in the water and used

  B1 Biremes Experience soon proved that longer ships posed a new set of problems: They were weaker structurally, more difficult to maneuver, and presented a larger target to anyenemy ship with a ram. In the 8th century BC Mediterranean shipbuilders eliminated these problems with the bireme , a war galley built to accommodate two levels, or banks , of oarsmen. Oarsmen on the lower level rowed oars from ports cut into the side of the vessel, while those above rowed from the deck. This arrangemen...

• Nixon's Checkers Speech Under attack for having used a secret campaign fund for his personal expenses, Richard M.

  The first way is to be a rich man. I don't happen to be a rich man so I couldn't use that. Another way that is used is to put your wife on the payroll. Let me say, incidentally, my opponent, my opposite number for the Vice Presidency on the Democraticticket, does have his wife on the payroll. And has had her on his payroll for the ten years—the past ten years. Now just let me say this. That's his business and I'm not critical of him for doing that. You will have to pass judgment on that particul...

• Number Systems I INTRODUCTION Number Systems, in mathematics, various notational systems that have been or are being used to represent the abstract quantities called numbers.

• Pi. Pi, Greek letter (p) used in mathematics as the symbol

• Lung. I INTRODUCTION Lung, either of a pair of elastic, spongy organs used

  lead to emphysema, which is caused by wholesale destruction of alveoli. Other lung disorders include pneumonia, or inflammation of the lungs, which is usually causedby viruses or bacteria; pneumothorax, or collapse of the lung; pulmonary edema, or fluid in the lung; and pleural effusion, or fluid on the pleura. Pulmonary embolismoccurs when a blood clot or other foreign substance lodges in the lungs and blocks the major pulmonary arteries. Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corp...

• Number (mathematics) I INTRODUCTION Number (mathematics), word or symbol used to designate quantities or entities that behave like quantities.

• Puli. Puli (pl. pulik), breed of herding dog, used as a

• Eumenides (Good-Tempered Ones) Greek The ironic name Greek people used for the Erinyes, fearsome creatures whose name means Furies.

• Pluto Greek and Roman A name used to refer to the god of the underworld.

• Fornax (Furnace) Roman A goddess of baking, who oversaw the ovens used for baking so that they did not become too hot and burn the roasting corn or bread.

• 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...

• Map - geography.

  Relief MapRelief maps are three-dimensional models of the terrain in an area; on them, color and scale are used to indicate geographicalfeatures rather than simply to delineate political boundaries. Because of this feature, relief maps are extensively used in engineeringand the military. This map shows portions of Alaska and northwestern Canada.United States Geological Survey Among the most important of the special-purpose maps are hydrographic and aviation charts. Hydrographic charts are used f...

• Electronics.

  electronic circuits. The resistors are made from carbon mixtures, metal films, or resistance wire and have two connecting wires attached. Variable resistors, with anadjustable sliding contact arm, are often used to control volume on radios and television sets. E Capacitors Capacitors consist of two metal plates that are separated by an insulating material ( see Capacitor). If a battery is connected to both plates, an electric charge will flow for a short time and accumulate on each plate. If th...

• Genetic Engineering.

  Pseudomonas fluorescens bacterium. The genetically altered Pseudomonas fluorescens bacterium produces light in proportion to the amount of its activity in breaking down the naphthalene, thus providing a way to monitor the efficiency of the process ( see Bioremediation). A3 Medicine In 1982 the United States Food and Drug Administration (FDA) approved for the first time the medical use of a recombinant DNA protein, the hormone insulin, whichhad been cloned in large quantities by inserting th...

• Hardware (computer).

  Magnetic tape drives use magnetic tape similar to the tape used in VCR cassettes. Tape drives have a very slow read/write time, but have a very high capacity; in fact,their capacity is second only to hard disk drives. Tape drives are mainly used to back up data. Compact disc drives store information on pits burned into the surface of a disc of reflective material ( see CD-ROM). CD-ROMs can store up to 737 megabytes (MB) of data. A Compact Disc-Recordable (CD-R) or Compact Disc-ReWritable (CD-RW)...

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

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

• Corn - biology.

  small larvae of the cucumber beetles feed on the root system of the developing plants. VII PRODUCTION AND CONSUMPTION World output of corn at the beginning of the 21 st century was about 603 million metric tons annually; in volume of production, corn ranked first, ahead of rice and wheat. A net gain of about 51 percent in production was realized during the last two decades; intensive cultivation with heavy use of fertilizer and herbicides wasresponsible for the increase. The United States is t...

• 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,...

• Drug Dependence.

  these drugs develops rapidly, no withdrawal syndrome is apparent when they are discontinued. Phencyclidine, or PCP, known popularly by such names as “angel dust” and “rocket fuel,” has no medical purpose for humans but is occasionally used by veterinarians asan anesthetic and sedative for animals. It became a common drug of abuse in the late 1970s, and is considered a menace because it can easily be synthesized. Itseffects differ from those of other hallucinogens. LSD, for example, produces deta...

• Laser.

  their atoms into laser light. Consequently, they are the most powerful continuous wave (CW) lasers—that is, lasers that emit light continuously rather than in pulses. C Liquid Lasers The most common liquid laser media are inorganic dyes contained in glass vessels. They are pumped by intense flash lamps in a pulse mode or by a separate gas laserin the continuous wave mode. Some dye lasers are tunable, meaning that the color of the laser light they emit can be adjusted with the help of a prism lo...

• bts devoir d'anglais

  2 Devoir 1 écrit Voici votre premier devoir écrit. Pour le réaliser, consultez la page d’accueil de l’onglet « Devoirs ». Seules les 2 parties Évaluation sont à envoyer \ au Cned. Document écrit en Langue Vivante étrangère Today’s Forecast: Cloudy, Newsweek, 10/11/2008 Vous le trouverez dans le recueil de documents supports des devoirs de BT\ S. Prenez-en connais- sance et notez les éléments importants nécessaires à la ré\ alisation de votre devoir. Exercices d’aide à la compréhensio...

• Antibiotics.

  In some species of bacteria the cell wall consists primarily of a thick layer of peptidoglycan. Other species have a much thinner layer of peptidoglycan and an outer aswell as an inner membrane. When bacteria are subjected to Gram's stain, these differences in structure affect the differential staining of the bacteria with a dye calledgentian violet. The differences in staining coloration (gram-positive bacteria appear purple and gram-negative bacteria appear colorless or reddish, depending on t...

• 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...

• Sewage Disposal.

  greater load on the piping system and the treatment plant. The amount of storm-water drainage to be carried away depends on the amount of rainfall as well as on the runoff or yield of the watershed ( see Drainage). A typical metropolitan area discharges a volume of wastewater equal to about 60 to 80 percent of its total daily water requirements, the rest being used for washingcars and watering lawns, and for manufacturing processes such as food canning and bottling. B Composition The composi...

• Fungus - biology.

  Many fungi can reproduce by the fragmentation of their hyphae. Each fragment develops into a new individual. Yeast, a small, single-celled fungus, reproduces bybudding, in which a bump forms on the yeast cell, eventually partitioning from the cell and growing into a new yeast cell. V CLASSIFICATION OF FUNGI Scientists have long disagreed about how to classify fungi, and the classification systems are still developing. The first description of fungi was published in 1729 byItalian botanist Pier...

• Stone Age.

  limestone, quartzite, and indurated shale. Ground stone tools could be made on a wider range of raw material types, including coarser grained rock such as granite. Flaking produces several different types of stone artifacts, which archaeologists look for at prehistoric sites. The parent pieces of rock from which chips have beendetached are called cores, and the chips that have been removed from cores are called flakes. A flake that has had yet smaller flakes removed from one or more edgesin orde...

• Criminal Punishment.

  In the United States and Canada, younger offenders may be sentenced to highly regimented, military-style correctional programs known as boot camps. Generally,offenders volunteer to participate in boot camp programs to avoid other types of incarceration. At boot camps, officials subject offenders to strict discipline and physicaltraining. They also provide educational or vocational programs. Boot camps serve as an alternative to traditional, long-term incarceration and attempt to train offenderst...

• Tennis.

  and interpret rules. The head official on the court, called the chair umpire, sits on a tall chair at one end of the net. A varying number of line judges sit around the courtbeyond the path of the players. Line judges determine whether serves and shots are good or out. A net-cord judge may be employed to determine when a ball touchesthe top of the net, and a foot-fault judge may watch for that specific infraction. In the 1980s electronic devices began to be used in some professional tournaments...

• Geology.

  terminology. Today the geologic time scale is generally agreed upon and used by scientists around the world, dividing time into eons, eras, periods, and epochs. Everyfew years, the numerical time scale is refined based on new evidence, and geologists publish an update. Geologists use several methods to determine geologic time. These methods include physical stratigraphy, or the placement of events in the order of their occurrence,and biostratigraphy, which uses fossils to determine geologic time...

• Fire - chemistry.

  were usually natural caves. Eventually people learned to dip branches in pitch to form torches. They created crude lamps by filling a hollowed out piece of stone withmoss soaked in oil or tallow (a substance derived from animal fat). By cooking with fire, prehistoric people made the meat of the animals they killed more palatable and digestible. They learned to preserve meat by smoking it over a fire,vastly decreasing the danger of periodic starvation. Cooking also enabled them to add some for...

• 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...

• Alphabet I INTRODUCTION Bengali Script India developed a number of different writing systems over the course of its history.

  A Pictographic and Ideographic Systems Early systems of writing used pictures to represent things and then to represent the sounds of those things. Pictographic writing, in which a simplified picture of the sunstood for the word sun, was probably the first step toward a written language. Chinese began as a pictographic language. To represent abstract ideas, the Chinese writing system combined pictographs. For example, the pictographs for sun and tree were combined to represent the concept of...

• Pollution.

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

• 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...

• Camel - biology.

  of water in the stomach or hump as was once commonly believed. Unlike other mammals, however, the camel can survive as long as three weeks without drinking,depending on the water content of its food. It can survive a water loss of about 40 percent of its normal body weight. In comparison, a loss of 15 percent is usually fatalfor humans. Camels can go without water due to several unique adaptations to their environment. The camel conserves more water in its body than any other mammal. It excretes...

• Gemstones.

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

• Hormone.

  women is called a follicle-stimulating hormone. When a follicle-stimulating hormone binds to an ovary cell, it stimulates the enzymes needed for the synthesis ofestradiol, a female sex hormone. Another gonadotropin called luteinizing hormone regulates the production of eggs in women and the production of the male sexhormone testosterone. Produced in the male gonads, or testes, testosterone regulates changes to the male body during puberty, influences sexual behavior, and playsa role in growth. T...

• Telecommunications.

  commonly referred to as wireless communications, use technologies such as cordless telephones, cellular radio telephones, pagers, and satellites. Wirelesscommunications offer increased mobility and flexibility. In the future some experts believe that wireless devices will also offer high-speed Internet access. C Wires and Cables Wires and cables were the original medium for telecommunications and are still the primary means for telephone connections. Wireline transmission evolved fromtelegraph...

• Nanotechnology.

  ever-finer method of reducing material to the nanoscale size. Instead, nanostructures would be assembled atom by atom and molecule by molecule, from the atomiclevel up, just as occurs in nature. However, assembly at this scale has its own challenges. In school, children learn about some of these challenges when they study the random Brownian motion seen in particles suspended in liquids such as water. Theparticles themselves are not moving. Rather, the water molecules that surround the particles...

• 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...

• Fishing.

  directly to the spool and turns the spool one rotation at a time. C Fishing Lines Fishing lines serve as the link between the angler’s reel and the lure or bait. The most popular line used for sportfishing is monofilament nylon line, which is strong anddurable and has a certain amount of stretch, which helps when an angler sets the hook. The line comes in a variety of strengths, from 2-pound test to more than 100-pound test. (Pound test is the amount of pressure that can be put on a line before...

• Horse - biology.

  Horses reach sexual maturity at about one and a half years. The estrous cycle in the mare—a mature female horse—typically lasts 21 days. During the first five days ofthe cycle, the mare is usually receptive to mating. The estrous cycle stops during winter and resumes in the spring, which is the start of the breeding season. Astallion—a mature male horse—approaching a mare in estrus engages in various courtship rituals. These include uttering nickering sounds and sniffing and licking themare’s ge...

• Greek Art and Architecture - USA History.

  The struggle between these two city-states and their allies ultimately led to the Peloponnesian War (431-404 BC), which Sparta won. Despite this conflict, the 5th century, often called the Classical period, is usually considered the culmination of Greek art, architecture, and drama, with its highest achievements being the Temple ofZeus at Olympia, the Parthenon in Athens, and the plays of Athenian dramatists Aeschylus, Sophocles, Euripides, and Aristophanes. The 4th century, or Late Classical p...

• bbb

  "Look lively, Miss Hill, please." She would not cry many tears at leaving the Stores. But in her new home, in a distant unknown country, it would not be like that. Then she would be married--she, Eveline. People would treat her with respect then. She would not be treated as her mother had been. Even now, though she was over nineteen, she sometimes felt herself in danger of her father's violence. She knew it was that that had given her the palpitations. When they were growing up he had never gone...

• Dubliners

  "Look lively, Miss Hill, please." She would not cry many tears at leaving the Stores. But in her new home, in a distant unknown country, it would not be like that. Then she would be married--she, Eveline. People would treat her with respect then. She would not be treated as her mother had been. Even now, though she was over nineteen, she sometimes felt herself in danger of her father's violence. She knew it was that that had given her the palpitations. When they were growing up he had never gone...

• Metalwork I INTRODUCTION Metalwork, in the fine arts, objects of artistic, decorative, and utilitarian value made of one or more kinds of metal--from precious to base--fashioned by either casting, hammering, or joining or a combination of these techniques.

  Early Bronze DiskThis disk with the head of Acheloos, an Etruscan river god, was made of bronze, an alloy of copper and tin, sometime inthe early 5th century bc. It comes from the necropolis of Monte Quaglieri in Tarquinia. Alloys are made by smelting twodifferent metals together.Scala/Art Resource, NY Knowledge of smelting ultimately led to knowledge of mixing different ores together in the smelting process to produce simple alloys. This followed an intermediateperiod, about 3000 BC, when comp...

• Greek Art and Architecture - history.

  powerful independent city-states. From 334 to 323 BC, Alexander the Great extended his father's empire into Asia Minor (now Turkey), Syria, Egypt, Persia, Afghanistan, and as far as India. D The Hellenistic Period (323-31 BC) Although Alexander the Great extended Greek civilization far beyond the Greek mainland and the boundaries of the Aegean Sea, his empire did not survive his death in 323.After Alexander died, his generals and successors divided the empire into a number of kingdoms: Ptolem...

• African Music I INTRODUCTION Sacred Christian Music of Nigeria Among the Igede people of Nigeria, Christianity has been syncretized with the existing religious belief system.

  III INSTRUMENTS Traditional Timbila of MozambiqueAmong the Chopi, who have lived for centuries along the coast of Mozambique, there is a highly developed tradition ofsongwriting and composing for timbila (xylophone) orchestras. Elaborate migodo (dance suites), interspersed with poeticsongs pertaining to village life, are often performed to these compositions. Timbila music is now recognized as the nationalmusic of Mozambique."Eduardo Durao Mauaia" from Eduardo Durao and Orquestra Durao: Timbil...

• Electronic Music I INTRODUCTION Electronic Music, music that requires the use of electronic devices to produce or manipulate sound during its composition and performance.

  III SYNTHESIZERS AND OTHER ELECTRONIC TECHNOLOGY Moog SynthesizerThe musical synthesizer was invented by American Robert Moog. Soon after Moog introduced an early version in 1964, itbecame known as the “Moog Synthesizer,” and then simply as the “Moog.” Here, Japanese composer Isao Tomita uses aMoog synthesizer in his studio.Huynh Cong/AP/Wide World Photos In the 1950s sound synthesizers were developed, principally in the United States. Synthesizers enabled composers to produce sounds electroni...