176 résultats pour "using"

• Frog (animal) - biology.

  which means that their body temperature depends on the temperature of the surrounding environment. Few species can tolerate temperatures below 4°C (40°F) orabove 40°C (104°F), and many species can survive only within a narrower range of temperatures. In addition, frogs’ thin, moist skin offers little protection againstwater loss, and when on land the animals must guard against drying out. Many frogs are active at night because temperatures are cooler and humidity is higher thanduring the day. In...

• Aztec Empire.

  tribute to the empire in agricultural products, which were used to finance public projects. All able-bodied men owed military service to the empire. Citizens could also bedrafted to work on public lands or build temples, dikes, aqueducts, and roads. Although Aztec society had strict classes, a person’s status could change based on his or her contribution to society. Commoners could improve their rank, especially byperforming well in battle, and become prosperous landowners. Young people of some...

• Aztec Empire - USA History.

  tribute to the empire in agricultural products, which were used to finance public projects. All able-bodied men owed military service to the empire. Citizens could also bedrafted to work on public lands or build temples, dikes, aqueducts, and roads. Although Aztec society had strict classes, a person’s status could change based on his or her contribution to society. Commoners could improve their rank, especially byperforming well in battle, and become prosperous landowners. Young people of some...

• Diving (sport).

  water that creates a larger, more noticeable splash after the diver’s body displaces water under the surface. To minimize this upjet, top-level divers make a quickswimming motion by releasing their hands and collapsing their arms as they submerge. Instead of a large splash, the surface of the water appears to boil as the airbubbles rise from the diver’s entry. For feetfirst entries, which are rare in top-level competitions, divers place their legs and feet together while pointing their toes down...

• Extrasolar Planets - astronomy.

  When a planet passes in a front of the star it orbits—an event called a transit—it causes a small dip in the brightness of the star. Measuring the slight change in thebrightness can be used not only to directly detect a planet, but to determine its size and orbit. However, the planet needs to orbit in a plane that lies in a telescope’sline of sight on the star. Despite long odds, Earth-based telescopes have detected and studied a few exoplanets using this method. The first space telescope design...

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

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

• 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...

• Gravitation I INTRODUCTION Gravitation, the force of attraction between all objects that tends to pull them toward one another.

  precise observations possible, and Galileo was one of the first to use a telescope to study astronomy. In 1609 Galileo observed that moons orbited the planet Jupiter, afact that could not reasonably fit into an earth-centered model of the heavens. The new heliocentric theory changed scientists' views about the earth's place in the universe and opened the way for new ideas about the forces behind planetarymotion. However, it was not until the late 17th century that Isaac Newton developed a theory...

• Gravitation - astronomy.

  precise observations possible, and Galileo was one of the first to use a telescope to study astronomy. In 1609 Galileo observed that moons orbited the planet Jupiter, afact that could not reasonably fit into an earth-centered model of the heavens. The new heliocentric theory changed scientists' views about the earth's place in the universe and opened the way for new ideas about the forces behind planetarymotion. However, it was not until the late 17th century that Isaac Newton developed a theory...

• Asteroid - astronomy.

  Asteroids of the S type, related to the stony iron meteorites, make up about 15 percent of the total population of asteroids that can be seen from Earth. Much rarer arethe M-type objects, corresponding in composition to the meteorites known as “irons.” These objects are made up of an iron-nickel alloy and may represent the cores ofbodies that were large enough to differentiate into layers and to melt deep inside. Their rocky outer layers may have been removed by impacts with other asteroids . A...

• Geometry I INTRODUCTION Geometry, branch of mathematics that deals with shapes and sizes.

  Conic sections, a commonly studied topic of geometry, are two-dimensional curves created by slicing a plane through a three-dimensional hollow cone. A Euclid’s Postulates Euclid, who lived about 300 BC, realized that only a small number of postulates underlay the various geometric theorems known at the time. He determined that these theorems could be deduced from just five postulates. 1. A straight line may be drawn through any two given points. 2. A straight line may be drawn infinitely or be...

• Mesoamerica.

  for cooking. In other regions, the earliest ceramics are more sophisticated technically and aesthetically. At around 1800 BC in the Pacific coastal region of Soconusco (in what is now southeastern Chiapas State, Mexico), the earliest pottery was very complex both in forms and decoration. It seems to have had a social function and beenused primarily for ritual feasting. III MAJOR CIVILIZATIONS Over a period of 3000 years, beginning in about 1500 BC, a number of important cultures emerged in M...

• Skiing.

  Safety is very important to all skiers, and all Alpine resorts have a ski patrol. The ski patrol’s responsibility is to take care of injured skiers, to mark hazardous spots ontrails, to make sure that trails are in good condition before opening them, and, at times, to act as traffic police in congested areas. Skiers are also responsible for takingtheir own safety into consideration, as well as that of others. Anyone who participates in the sport should be aware of the Skier’s Responsibility Code...

• George Bush.

  1986 it was folded into Harken Energy Corporation, another Texas petroleum company. Bush served as a consultant and a member of Harken’s board of directors. In 1987 Bush relocated his family to Washington, D.C., to assist his father in his bid to become president. He worked as a campaign adviser at his father’s nationalcampaign headquarters, serving as a liaison to the media and to conservative and Christian leaders. He was a trusted confidant of his father and mother, whosometimes dispatched Bu...

• George Bush - USA History.

  1986 it was folded into Harken Energy Corporation, another Texas petroleum company. Bush served as a consultant and a member of Harken’s board of directors. In 1987 Bush relocated his family to Washington, D.C., to assist his father in his bid to become president. He worked as a campaign adviser at his father’s nationalcampaign headquarters, serving as a liaison to the media and to conservative and Christian leaders. He was a trusted confidant of his father and mother, whosometimes dispatched Bu...

• Cosmology - astronomy.

  In 1917 American scientist Harlow Shapley measured the distance to several groups of stars known as globular clusters. He measured these distances by using amethod developed in 1912 by American astronomer Henrietta Leavitt. Leavitt’s method relates distance to variations in brightness of Cepheid variables, a class of starsthat vary periodically in brightness. Shapley’s distance measurements showed that the clusters were centered around a point far from the Sun. The arrangement of theclusters was...

• Dwight D.

  maneuvers in Louisiana in 1941, he played a leading role as a staff officer, adding to his reputation and securing him a promotion to brigadier general. On December 7,1941, Japan attacked Pearl Harbor, Hawaii, and the next day the United States entered World War II against the Axis Powers (Japan, Germany, and Italy). A weeklater, the army’s new chief of staff, General George C. Marshall, called Eisenhower to Washington, D.C., and put him in charge of the War Plans Division. Opinions differed on...

• Light - astronomy.

  Each different frequency or wavelength of visible light causes our eye to see a slightly different color. The longest wavelength we can see is deep red at about 700 nm.The shortest wavelength humans can detect is deep blue or violet at about 400 nm. Most light sources do not radiate monochromatic light. What we call white light,such as light from the Sun, is a mixture of all the colors in the visible spectrum, with some represented more strongly than others. Human eyes respond best to greenlight...

• 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...

• Terrorism.

  exploitation, ethnic discrimination, and religious persecution. Perceived inequities in the distribution of wealth and political power have led some terrorists to attempt tooverthrow democratically elected governments. To achieve a fairer society, they would replace these governments with socialist or communist regimes. Left-wingterrorist groups of the 1960s and 1970s with such aims included Germany’s Baader-Meinhof Gang, Italy’s Red Brigades, and the Weather Underground ( see Weathermen) in the...

• Banking.

  loans, and some commercial loans in addition to checking accounts and time deposits. Credit unions, SLAs, and savings banks help encourage thriftiness by paying interest to consumers who put their money in savings deposits. Consequently, creditunions, SLAs, and savings banks are often referred to as thrift institutions. Of the various types of banks in the United States, commercial banks account for the greatest single source of the financial industry’s assets. In 2000 the 8,528commercial banks...

• French Canadian Nationalism - Canadian History.

  The revolution ended in independence for the Americans, who named their new country the United States of America. In the aftermath, thousands of people who hadopposed the American Revolution migrated from what was now the United States to British North America. These people, known as the United Empire Loyalists, settledin the Maritimes, where they greatly increased the British majority over the Acadians, and in Québec. Some settled near francophone communities around Montréal andin the Eastern T...

• Analyse spectrale

• Cours de pollution et sans licence

  Cours Pollution & Nuisances – LFSNA3 - 2 - Plan du cours Chapitre I : Introduction : causes et types de pollutions Chapitre II : la pollution atmosphérique et ses effets 1- Les différents types de polluants: CO, SO 2, NO 2, COV, aérosols, métaux,… 2- Problèmes environnementaux liés aux polluants atmosphériques 3- Perturbations des cycles biogéochimiques par la pollution 4-Conséquences écotoxicologiques de la pollution a tmosphérique Chapitre III...

• Complex Numbers I INTRODUCTION Complex Numbers, in mathematics, the sum of a real number and an imaginary number.

  sometimes referred to as an Argand diagram. If a complex number in the plane is thought of as a vector joining the origin to that point, then addition of complexnumbers corresponds to standard vector addition. Figure 1 shows the complex number 3 + 2 i obtained by adding the vectors 1 + 4 i and 2 - 2 i. Figure 1: Complex Plane in Cartesian CoordinatesThis graph illustrates the addition of two complex numbers by using vectors in the complex plane with cartesiancoordinates. The parallelogram shows...

• Archaeology.

  Prehistoric archaeology is practiced by archaeologists known as prehistorians and deals with ancient cultures that did not have writing of any kind. Prehistory, a term coined by 19th-century French scholars, covers past human life from its origins up to the advent of written records. History—that is, the human past documented insome form of writing—began 5000 years ago in parts of southwestern Asia and as recently as the late 19th century AD in central Africa and parts of the Americas. Becaus...

• Wrestling.

  (4) Escapes are scored when a wrestler, controlled by the opponent on the mat, frees himself or herself and moves to a standing position, facing the opponent. Common escapes include the standup and the sitout. V HISTORY Wrestling has been popular throughout recorded history. Origins of the sport can be traced back 15,000 years through depictions in cave drawings in France. EarlyEgyptian and Babylonian reliefs depict wrestlers using most of the holds known to the present-day sport. In ancient G...

• William Blake I INTRODUCTION William Blake (1757-1827), English poet, painter, and engraver, who created an unusual form of illustrated verse; his poetry, inspired by mystical vision, is among the most original, lyric, and prophetic in the language.

  Your spring & your day are wasted in play,And your winter and night in disguise. Both series of poems take on deeper resonances when read in conjunction. Innocence and Experience, “the two contrary states of the human soul,” are contrasted insuch companion pieces as “The Lamb” and “The Tyger.” Blake’s subsequent poetry develops the implication that true innocence is impossible without experience,transformed by the creative force of the human imagination. III BLAKE AS ARTIST The LambThe Lamb...

• Microprocessor.

  thin layer of oxide about 75 angstroms deep (an angstrom is one ten-billionth of a meter). Nearly every layer that is deposited on the wafer must be patterned accurately into the shape of the transistors and other electronic elements. Usually this is done in aprocess known as photolithography, which is analogous to transforming the wafer into a piece of photographic film and projecting a picture of the circuit on it. A coatingon the surface of the wafer, called the photoresist or resist, changes...

• 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...

• Euthanasia.

  permission from the family. B In Other Countries In 1995 the Northern Territory of Australia became the first jurisdiction to explicitly legalize voluntary active euthanasia. However, the federal parliament of Australiaoverturned the law in 1997. In 2001 The Netherlands became the first country to legalize active euthanasia and assisted suicide, formalizing medical practices that thegovernment had tolerated for years. Under the Dutch law, euthanasia is justified (not legally punishable) if the...

• baudelaire analyse L'ennemi

  Baudelaire highlighting the time that passes through a progression from the past to the present, the discouraging record of this stormy youth is underlined by the past composed «on fait» (vers 3) and by the proposition of consequence to the present. The metaphor continues in the mention of a nature which has undergone the meteorological elements in their destructive character, the past having left traces: a life ravaged by «le tonnerre et la pluie», by the blows of fate and the daily g...

• Royal Canadian Mounted Police.

  Perry declared prohibition unenforceable and canceled the policing contracts for the two provinces. The strength of the force dwindled further as its members wererecruited into the military. Many, including Perry, believed it would not last into peacetime. VI EXPANSION TO A NATIONAL ROLE After the war Newton W. Rowell, a federal cabinet minister, was sent across western Canada to assess the future of the Mounties. The options were either to eliminatethe North-West Mounted Police or to expand i...

• Drawing I INTRODUCTION Drawing, delineation of form upon a surface, usually a plane, by means of lines and tints or shading.

  In the monasteries of medieval Europe, religious texts were inscribed on parchment, then embellished with initial letters, decorative borders, and miniature scenes. InRomanesque Europe, drawings served as models to be copied for such manuscript illumination and also as cartoons ( see Cartoon), or studies, for frescoes, sculpture, and other arts. Subjects were usually treated as stylized symbols of religious truths. This viewpoint was countered in the Gothic period; the change was reflected in th...

• Interstellar Matter - astronomy.

  silhouette of a cloud of dust. At other times, it blocks only a percentage of the light from behind it, a process known by astronomers as extinction . The long, narrow dark lanes in the Milky Way as seen from Earth are examples of extinction. The amount of extinction is different for different wavelengths of light. A2 Reddening Starlight that does not get completely absorbed by interstellar dust can still be changed by the dust’s effects. As light passes through less dense patches of interstel...

• Magnetism I INTRODUCTION Magnetism, an aspect of electromagnetism, one of the fundamental forces of nature.

  the French physicist Paul Langevin produced a theory regarding the temperature dependence of the magnetic properties of paramagnets (discussed below), which wasbased on the atomic structure of matter. This theory is an early example of the description of large-scale properties in terms of the properties of electrons and atoms.Langevin's theory was subsequently expanded by the French physicist Pierre Ernst Weiss, who postulated the existence of an internal, “molecular” magnetic field inmaterials...

• Photosynthesis - biology.

  P680 in Photosystem II is now electron deficient because it has donated electrons to P700 in Photosystem I. P680 electrons are replenished by the water that has beenabsorbed by the plant roots and transported to the chloroplasts in the leaves. The movement of electrons in Photosystems I and II and the action of an enzyme split thewater into oxygen, hydrogen ions, and electrons. The electrons from water flow to Photosystem II, replacing the electrons lost by P680. Some of the hydrogen ions maybe...

• Folktales I INTRODUCTION "Little Red Riding Hood" The popular children's story "Little Red Riding

  seemed important to them. Thus, the Grimms postulated a common Indo-European origin for folktales, and the German philologist Theodor Benfey as well as theScottish writer William Clouston believed that stories diffused by way of travelers migrating east and west from India. Such theories, however, have proven incompleteand inadequate. Nevertheless, the research of these and other scholars greatly stimulated interest in folklore and folktales. The German scholar Max Muller held thatmyths originat...

• Artificial Intelligence.

  Work in AI has primarily focused on two broad areas: developing logic-based systems that perform common-sense and expert reasoning, and using cognitive andbiological models to simulate and explain the information-processing capabilities of the human brain. In general, work in AI can be categorized within three research anddevelopment types: symbolic, connectionist, and evolutionary. Each has characteristic strengths and weaknesses. A Symbolic AI Symbolic AI is based in logic. It uses sequences...

• Bowling.

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

• Army. I INTRODUCTION Army, military land forces of a nation, assembled, drilled, disciplined,

  disappearance for several centuries of large standing armies in Europe. A Middle Ages Feudalism was based on a concept of local defense, each baron or landowner governing land that had been given him by the king, and each lord having his ownpersonal protective forces recruited from among men who worked for him. In return, each lord and his men were pledged to annual service to the monarch and couldbe called on in special instances, as in the defense of Christendom during the Crusades. National...

• Native American Literature I INTRODUCTION Leslie Marmon Silko Native American writer Leslie Marmon Silko is perhaps best known for her first novel, Ceremony (1977), a coming-of-age story about a young man of mixed Native American and white ancestry.

  SequoyahNative Americans did not use a complex written language before the immigration of Europeans to the Americas. In theearly 1820s the Cherokee leader Sequoyah developed an alphabet and written language for his native tongue. ManyCherokee learned the new written language readily, and in 1828 they published the first Native American newspaper,written in both Cherokee and English.THE BETTMANN ARCHIVE Before Native Americans came into contact with Europeans, many tribes supplemented the spoken...

• 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...

• Computer Science.

  theoretical research is called algorithmic complexity. Computer scientists in this field seek to develop techniques for determining the inherent efficiency of algorithmswith respect to one another. Another area of theoretical research called computability theory seeks to identify the inherent limits of computation. Software engineers use programming languages to communicate algorithms to a computer. Natural languages such as English are ambiguous—meaning that theirgrammatical structure and vocab...

• Trigonometry I INTRODUCTION Trigonometry, branch of mathematics that deals with the relationships between the sides and angles of triangles and with the properties and applications of the trigonometric functions of angles.

  If point P, in the definition of the general trigonometric function, is on the y-axis, x is 0; therefore, because division by zero is inadmissible in mathematics, the tangent and secant of such angles as 90°, 270°, and -270° do not exist. If P is on the x-axis, y is 0; in this case, the cotangent and cosecant of such angles as 0°, 180°, and - 180° do not exist. All angles have sines and cosines, because r is never equal to 0. Since r is greater than or equal to x or y, the values of si...

• 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,...

• The way in which companies frame themselves, their products and their clients

• Computer Memory.

  been created, information can be retrieved but not changed. Newer technologies allow ROMs to be semi-permanent—that is, the information can be changed, but ittakes several seconds to make the change. For example, a FLASH memory acts like a ROM because values remain stored in memory, but the values can be changed. C External Memory External memory can generally be classified as either magnetic or optical, or a combination called magneto-optical. A magnetic storage device, such as a computer'shar...

• Circulatory System.

  C Additional Functions In addition to oxygen, the circulatory system also transports nutrients derived from digested food to the body. These nutrients enter the bloodstream by passingthrough the walls of the intestine. The nutrients are absorbed through a network of capillaries and veins that drain the intestines, called the hepatic portal circulation.The hepatic portal circulation carries the nutrients to the liver for further metabolic processing. The liver stores a variety of substances, suc...

• 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...