132 résultats pour "research"

• Columbus (Ohio) - geography.

  A balance among manufacturing, technology, research, and financial activities has helped Columbus’s economy to continue to boom. Much of the city’s expansion resultsfrom its function as a sophisticated service center. By 1990 manufacturing occupied only 12 percent of the area’s labor force. That contrasted with services, includinggovernment, finance, and transportation and utilities, which accounted for almost 60 percent of all employment. The two largest employers in Columbus are state governme...

• 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...

• 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...

• United Arab Emirates - country.

  III PEOPLE Most people living in the UAE (known as Emiris) are Arabs, a large majority of whom are city and town dwellers. A small number are nomadic (having no permanent home). The population has grown dramatically since the mid-1960s, largely due to the influx of oil workers to the country. Four-fifths of the UAE’s inhabitants areforeign workers and their families. The UAE also has a very youthful population, due to the large numbers of young foreign workers, a cultural preference for larg...

• 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...

• Genetics - biology.

  construct identical buildings. Just as each contractor would require a full copy of the blueprint to construct a complete building, each new cell needs a complete copy ofan organism’s genetic information to function properly. Organisms use two types of cell division to ensure that DNA is passed down from cell to cell during reproduction. Simple one-celled organisms and other organisms thatreproduce asexually—that is, without the joining of cells from two different organisms—reproduce by a proces...

• Inorganic Chemistry - chemistry.

  two electrically charged plates (positively charged top plate and negatively charged bottom plate). By measuring the difference in how fast these electron-laden oildrops fell when the metal plates were charged and uncharged, Millikan was able to calculate the total charge on each oil drop. Because each measurement was a wholenumber multiple of -1.60 × 10 -19 coulombs, Millikan concluded this was the charge carried by a single electron. Using Thomson’s electron charge-to-mass ratio, Millikan then...

• Louis Pasteur.

  In 1885, a young boy and his mother arrived at Pasteur’s laboratory; the boy had been bitten badly by a rabid dog, and Pasteur was urged to treat him with his newmethod. At the end of the treatment, which lasted ten days, the boy was being inoculated with the most potent rabies virus known; he recovered and remainedhealthy. Since that time, thousands of people have been saved from rabies by this treatment. Pasteur’s research on rabies resulted, in 1888, in the founding of a special institute in...

• Isotope - chemistry.

  depends on the fact that when water undergoes electrolysis, the lighter hydrogen isotope tends to come off first, leaving behind a residue of water that is enriched inthe heavier isotope. D Gaseous Diffusion This and the electromagnetic method of separating isotopes of uranium afforded the first large-scale separation ever achieved. The problem of separating uranium-235from uranium-238 arose in 1940 after the demonstration of the susceptibility of the 235 isotope to fission by neutrons. Uranium...

• Detroit - geography.

  of German and Irish immigrants. In the first half of the 20th century, the percentage of foreign-born residents declined, even though many immigrants arrived fromeastern Europe. During World War II (1939-1945), both whites and blacks were attracted from the South to work in the city’s defense industries. In 1950 foreign-bornand black residents each made up about 16 percent of the total population. In the five decades after 1950, the city lost almost half of its population, as many white resident...

• Human Sexuality.

  About six weeks after conception, if a Y chromosome is present in the embryo's cells (as it is in normal males), a gene on the chromosome directs the undifferentiatedgonads to become testes. If the Y chromosome is not present (as in normal females), the undifferentiated gonads will become ovaries. If the gonads become testes, they begin to produce androgens (male hormones, primarily testosterone) by about eight weeks after conception. These androgens stimulate development of the one set of the...

• United States House of Representatives.

  Because of the high cost of elections and the short two-year term of office, members of the House campaign almost constantly. They spend much of their time raisingcampaign funds, and they frequently return to their districts to keep in touch with voters. Because the elections are so frequent, House members tend to pay closeattention to how their votes in Congress will be seen in the short term. House members tend to come from wealthier family backgrounds than average Americans. Few working class...

• Michigan - geography.

  The interior location of Michigan in the northern part of North America results in a continental climate, characterized by four definite seasons with moist, mild to hotsummers and snowy, cold winters. Winds off of Lakes Michigan and Superior in winter create heavy snow accumulations in nearby areas. The tempering effects of LakeMichigan account for the presence of the state’s famous fruit-growing belt along the lake’s shore. Since the water is colder than the land in spring, the westerly windspa...

• Michigan - USA History.

  The interior location of Michigan in the northern part of North America results in a continental climate, characterized by four definite seasons with moist, mild to hotsummers and snowy, cold winters. Winds off of Lakes Michigan and Superior in winter create heavy snow accumulations in nearby areas. The tempering effects of LakeMichigan account for the presence of the state’s famous fruit-growing belt along the lake’s shore. Since the water is colder than the land in spring, the westerly windspa...

• ÉTRANGER — GROUPE 1, SESSION DE JUIN 1995 LANGUE VIVANTE 1- SÉRIES L ET ES/S

  dals as if ready to walk straight off the plane on to the beach. There 30 was a rising babble of drawling, twanging accents, loud laughter, shouts and whoops. "An artificial cheerfulness," said Sheldrak:e. "Fuelled by double martinis in many cases, I wouldn't be surprised. They know how people going on vacation are supposed to behave. They have lear- 35 ned how to do it. Look deep into their eyes and you will see anxiety and dread 6." [ •••...

• Kuiper Belt - astronomy.

  III RESEARCH The Kuiper Belt is an exciting area of research in astronomy. The discovery and astronomical exploration of the Kuiper Belt over the past decade have fueled arevolution in scientists’ views of the solar system. Today astronomers recognize the Kuiper Belt as the third major region of the solar system (the other two regions arethe inner solar system, with its small rocky planets, and the outer solar system, with its gas-giant planets). They believe that the belt helps explain Pluto’...

• science

  of the catalyst, including selectivity for the case of more complex catalytic pathways. Figure 2B suggests the local regeneration of deactivated areas as one possible starting point for such a design. In the case of island- forming reactants, for which the reaction oc- curs at the perimeter of these islands (34,35), the generation of additional boundaries should enhance reaction rates. What are good feedback laws for these objectives, and how can they be implemented? Hierarchical con- trol schem...

• Alzheimer's Disease.

  compared residents of Ibadan, Nigeria, who eat a mostly low-fat vegetarian diet, with African Americans living in Indianapolis, Indiana, whose diet included a variety ofhigh-fat foods. The Nigerians were less likely to develop Alzheimer’s disease compared to their U.S. counterparts. Some researchers suspect that health problems suchas high blood pressure, atherosclerosis (arteries clogged by fatty deposits), high cholesterol levels, or other cardiovascular problems may play a role in the devel...

• Sleep - biology.

  V FUNCTIONS OF SLEEP Although no one knows for sure why we sleep, there are a number of theories. Sleep may have evolved to protect animals from their predators by reducing theiractivity during the times when they are most vulnerable. Research has shown that REM and NREM sleep may serve specific biological functions. Sleep deprivation studies reveal that humans and other animals respond to sleeploss in the same way. When study subjects are deprived of REM sleep, they tend to spend longer period...

• Water - chemistry.

  flourides in drinking water has been found to reduce tooth decay. See Fluorine. Seawater contains, in addition to concentrated amounts of sodium chloride, or salt, many other soluble compounds, as the impure waters of rivers and streams areconstantly feeding the oceans. At the same time, pure water is continually lost by the process of evaporation, and as a result the proportion of the impurities that givethe oceans their saline character is increased. See Ocean and Oceanography. VII WATER...

• 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...

• Tuberculosis.

  TB has existed for thousands of years. Scars on a skull found in Turkey indicate the presence of the disease 500,000 years ago. Scientists also have found tubercles inmummified bodies from ancient Egypt. References to TB can be found in the writings of ancient Babylonia, Egypt, and China. The term tuberculosis was first used in 1839; it was derived from the Latin word tubercula, meaning small lump, referring to the small scars seen in tissues of infected individuals. TB reappeared in Europe...

• Schizophrenia.

  alcohol than other people. The use of alcohol and drugs often worsens the symptoms of schizophrenia, resulting in relapses and hospitalizations. IV CAUSES Schizophrenia appears to result not from a single cause, but from a variety of factors. Most scientists believe that schizophrenia is a biological disease caused by geneticfactors, an imbalance of chemicals in the brain, structural brain abnormalities, or abnormalities in the prenatal environment. In addition, stressful life events maycontri...

• Sudan - country.

  B Principal Cities and Political Divisions The principal city is Khartoum, the capital; other major cities include Omdurman and Khartoum North, major industrial centers, and Port Sudan, a seaport on the RedSea. Sudan is divided into 26 states. C Religion and Language About 70 percent of the people of Sudan are Muslims, some 15 percent are Christians, and most of the remainder follow traditional religions. The people of northernSudan are predominantly Sunni Muslims (Sunni Islam). Most of the pe...

• Depression (psychology).

  IV CAUSES Some depressions seem to come out of the blue, even when things are going well. Others seem to have an obvious cause: a marital conflict, financial difficulty, or somepersonal failure. Yet many people with these problems do not become deeply depressed. Most psychologists believe depression results from an interaction betweenstressful life events and a person’s biological and psychological vulnerabilities. A Biological Factors Depression runs in families. By studying twins, researche...

• Diabetes Mellitus.

  Once diabetes is diagnosed, treatment consists of controlling the amount of glucose in the blood and preventing complications. Depending on the type of diabetes, thiscan be accomplished through regular physical exercise, a carefully controlled diet, and medication. Individuals with Type 1 diabetes must receive insulin, often two to four times a day, to provide the body with the hormone it does not produce. Insulin cannot be takenorally, because it is destroyed in the digestive system. Consequent...

• Montréal - geography.

  percent), and Eastern Orthodox (2.8 percent) religions. Another 5.4 percent claim no religious affiliation. IV EDUCATION AND CULTURE Montréal has a large number of private schools, most of them partially funded by the province. Like the rest of Québec province, Montréal has two public schoolsystems, one for French speakers and one for English speakers. The Charter of the French Language (1977), known as Bill 101, restricts access to English-languageschools and requires children of immigrants t...

• Montréal - Geography.

  percent), and Eastern Orthodox (2.8 percent) religions. Another 5.4 percent claim no religious affiliation. IV EDUCATION AND CULTURE Montréal has a large number of private schools, most of them partially funded by the province. Like the rest of Québec province, Montréal has two public schoolsystems, one for French speakers and one for English speakers. The Charter of the French Language (1977), known as Bill 101, restricts access to English-languageschools and requires children of immigrants t...

• Stress (psychology).

  blood flow is diverted from the internal organs and skin to the brain and muscles. Breathing speeds up, the pupils dilate, and perspiration increases. This reaction issometimes called the fight-or-flight response because it energizes the body to either confront or flee from a threat. Another part of the stress response involves the hypothalamus and the pituitary gland, parts of the brain that are important in regulating hormones and many otherbodily functions. In times of stress, the hypothal...

• Comte, Isidore-Auguste-Marie-François-Xavier

  1 Life Auguste Comte was born in Montpellier, France. He attended the École Polytechnique, from which he was expelled in 1816, for political reasons. Comte's main concern throughout his life was resolving the political, social and moral problems caused by the French Revolution. To that end, he embarked upon an encyclopedic work, which he first conceived under the inspiration of Henri de Saint-Simon , for whom he worked as secretary from 1817 to 1824. At that time, he proposed several pla...

• New Orleans - geography.

  D Metropolitan Region The New Orleans metropolitan region covers 8,800 sq km (3,400 sq mi) and includes the counties—known in Louisiana as parishes— of Orleans, Jefferson, Saint Bernard, Saint Charles, Saint John the Baptist, Saint Tammany, Saint James, and Plaquemines. At the center is the city of New Orleans, which is coextensive withOrleans Parish. It has a land area of 468 sq km (181 sq mi). Extending from this base are numerous suburban towns in the surrounding parishes. Metairie, Harahan...

• Economics.

  Malthus, nature's check was “positive”: “The power of population is so superior to the power of the earth to produce subsistence for man, that premature death must insome shape or other visit the human race.” The shapes it took included war, epidemics, pestilence and plague, human vices, and famine, all combining to level theworld's population with the world's food supply. The only escape from population pressure and the horrors of the positive check was in voluntary limitation of population, no...

• 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...

• United States Senate.

  providing for military forces, and declaring war. Article I, Section 8, also gives Congress implied powers—to “make all laws which shall be necessary and proper” forcarrying out the enumerated powers, and to investigate and oversee the executive branch. The Senate also has the power to conduct impeachment trials against thepresident, federal judges, and other officials. The Senate can only impeach someone after the House brings charges, however. A two-thirds majority vote of thesenators in the c...

• New Jersey - geography.

  C Soils Broadly defined, all of New Jersey’s soils are podzolic soils; that is, they are acidic and contain fairly high amounts of iron oxides. The soils in northern New Jersey areirregular in quality and contain rock fragments and small stones deposited by the continental glaciers of the last Ice Age. The soils of the inner coastal plain, unaffectedby glaciation, are the richest in the state, while those of the outer coastal plain are generally infertile. The newer soil classification system d...

• New Jersey - USA History.

  C Soils Broadly defined, all of New Jersey’s soils are podzolic soils; that is, they are acidic and contain fairly high amounts of iron oxides. The soils in northern New Jersey areirregular in quality and contain rock fragments and small stones deposited by the continental glaciers of the last Ice Age. The soils of the inner coastal plain, unaffectedby glaciation, are the richest in the state, while those of the outer coastal plain are generally infertile. The newer soil classification system d...

• Le retrait américain en irak

  Les États -Unis se préparent au retrait total des forces armées états-uniennes del’Iraq. La vitesse de ce retrait dépendra de l’état de la sécurité interne et de la stabilité en Iraq au cours de la progression du rapatriement des forces armées. La sécurité et la stabilité seront assurés si les principaux groupes d’opposition, les Sunnites et les Kurdes, continuent de rivaliser passivement à travers un parti politique. Les États -Unis devront aussi surveiller le gouvernement S...

• New York Public Library.

• Chargé d'étude marketing (G-B)

• James WatsonIINTRODUCTIONJames Watson, born in 1928, American molecular biologist and cowinner of the 1962 Nobel Prize in physiology or medicine.

• James Watson.

• James Watson

• Anthropology.

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

• language in society

  2 Acknowledgement First and foremost, I wish to express my deep appreciation to my supervisor Dr. Salah Kaouache for his patience, determination and guidance that have seen me through this project. His comments and clarifications have been for immense help to me in writing this dissertation. I am very grateful to him for his insightful feedback and constant encouragement throughout. I also thank Pr. Zahri Harouni, Pr. Hacene Saadi, Dr.Youcef Beghoul, Dr....

• Psychology.

  Clinical psychology is dedicated to the study, diagnosis, and treatment of mental illnesses and other emotional or behavioral disorders. More psychologists work in this field than in any other branch of psychology. In hospitals, community clinics, schools, and in private practice, they use interviews and tests to diagnose depression,anxiety disorders, schizophrenia, and other mental illnesses. People with these psychological disorders often suffer terribly. They experience disturbing symptoms t...

• Medicine.

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

• Marketing.

  Where advertising reaches a mass audience, personal or direct selling focuses on one customer at a time. That kind of individual attention makes direct sellingexpensive, but it also makes it effective. As the costs of personal selling have risen, the utilization of salespeople has changed. Simple transactions are completed byclerks. Salespeople are now used primarily where the products are complex and require detailed explanation, customized application, or careful negotiation over priceand paym...

• Cloning - biology.

  found that such embryo cells are totipotent (able to give rise to all the different cell types in the body). Exploiting this characteristic, scientists developed three techniques to clone embryo cells: blastomere separation, blastocyst division, and somatic cell nuclear transfer. A Blastomere Separation In blastomere separation, scientists fertilize an egg cell with a sperm cell in a laboratory dish. The resulting embryo is allowed to divide until it forms a mass of aboutfour cells. Scientist...

• Colleges and Universities.

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

• 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...