1600 résultats pour "their"

• Ice Ages.

  B Future Ice Ages The record of previous glacial activity is the best indicator for future ice ages. Scientists examine the evidence for the numerous 100,000-year glacial-interglacial cycleswithin the present ice age to attempt a forecast of future ice ages. Since all previous ice ages lasted tens of millions of years, our present ice age will likely continue fora considerable amount of time. Each glaciation begins slowly and may take 80,000 years or more to reach its maximum extent. A rapid me...

• Middle East - geography.

  years.Spectrum Colour Library Apart from the Nile River, which provides much of the water supply and irrigation systems of Egypt, and the Tigris and Euphrates rivers, which supply Iraq, Syria, andTurkey, there are no major rivers or navigable waterways. The Sea of Galilee (Lake Tiberias) in northern Israel, fed from the north by the shallow, unnavigable JordanRiver, provides Israel’s main source of fresh water. With such a limited water supply, access to water for drinking, irrigation, and hydro...

• Antarctica - geography.

  The geographic South Pole lies near the center of the continent in East Antarctica. This point is where all map lines of longitude converge at the southern end ofEarth’s axis of rotation. Distinct from the geographic south pole is the south magnetic pole, where the lines of force of Earth’s magnetic field emerge vertically,arching upward over the planet to enter Earth again at the north magnetic pole. The south-seeking end of a compass needle points to the south magnetic pole. Thesouth magnetic...

• Finland - country.

  Productive forestland is the most valuable natural resource of Finland. Spruce, pine, and silver birch are the principal trees used to manufacture wood and pulp andpaper products. Finland lacks coal and petroleum resources and is a net importer of energy resources. However, Finland does have significant deposits of peat, which is cut from thenumerous peat bogs that cover much of the north. Peat is an important heat source for homes, and it provides about 7 percent of Finland’s electricity needs....

• Development (biology) - biology.

  Understanding the molecular machinery within cells gives biologists a direct basis for understanding growth, because growth is the synthesis of new protoplasm, andbiologists know the basic mechanism of this synthesis. One key gap, however, exists in this knowledge. Biologists want to know not only how substances aresynthesized but also how growth is controlled so that the proportions of an animal or plant remain consistent from generation to generation. The direction and amountof growth, which a...

• 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...

• 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...

• Sir Louis-Hippolyte LaFontaine - Canadian History.

• Maryland - geography.

  Maryland has no large natural lakes. The largest body of water is a reservoir, Deep Creek Lake, which has a surface area of only 18 sq km (7 sq mi). It lies on theAllegheny Plateau, behind a dam on a tributary of the Youghiogheny River. C Coastline The deeply indented shoreline has a length of 5,134 km (3,190 mi), of which only 50 km (31 miles) fronts on the Atlantic Ocean. The most significant coastal feature isChesapeake Bay. In the bay are many islands and Kent Island is the largest. The sta...

• Maryland - USA History.

  Maryland has no large natural lakes. The largest body of water is a reservoir, Deep Creek Lake, which has a surface area of only 18 sq km (7 sq mi). It lies on theAllegheny Plateau, behind a dam on a tributary of the Youghiogheny River. C Coastline The deeply indented shoreline has a length of 5,134 km (3,190 mi), of which only 50 km (31 miles) fronts on the Atlantic Ocean. The most significant coastal feature isChesapeake Bay. In the bay are many islands and Kent Island is the largest. The sta...

• Democracy.

• Newfoundland and Labrador - Geography.

  Precipitation averages about 1,120 mm (about 44 in) yearly in Newfoundland. In Labrador precipitation varies from about 1,020 mm (about 40 in) in the southeast toabout 510 mm (about 20 in) in the extreme north. Heavy winter snowfalls are common, especially in Newfoundland. D Plant Life About one-third of Newfoundland is forested, and most of the rest of the island is made up of barren areas of reindeer moss and lichens. The forests consist almostentirely of conifers. The most important species...

• Newfoundland and Labrador - Canadian History.

  Precipitation averages about 1,120 mm (about 44 in) yearly in Newfoundland. In Labrador precipitation varies from about 1,020 mm (about 40 in) in the southeast toabout 510 mm (about 20 in) in the extreme north. Heavy winter snowfalls are common, especially in Newfoundland. D Plant Life About one-third of Newfoundland is forested, and most of the rest of the island is made up of barren areas of reindeer moss and lichens. The forests consist almostentirely of conifers. The most important species...

• 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...

• Argentina - country.

  Patagonia lies in the rain shadow of the Andes and so receives little moisture. As a result it is used primarily for grazing sheep, although some crops are grown on smallfarms in irrigated valleys. Several major oil fields also are in Patagonia. At the southern tip of Patagonia is Tierra del Fuego, a large mountainous island shared byArgentina and Chile. B Rivers and Lakes Most of Argentina’s rivers empty into the Atlantic Ocean. Three rivers—the Paraná, Paraguay, and Uruguay—flow generally sou...

• Djibouti (country) - country.

  l’Unité et de la Démocratie (FRUD; Front for the Renewal of Unity and Democracy) represents the Afar minority. The Parti National Démocratique (PND; Democratic National Party) and the Parti du Renouveau Démocratique (PRD; Democratic Renewal Party) are both small opposition parties favoring democratic reforms. VI HISTORY Djibouti lies at a major global crossroads where, some 100,000 years ago, early humans migrated from Africa to the Middle East. Livestock herding, which remainsimportant...

• Nova Scotia - Geography.

  summer. Nova Scotia receives an average of more than 1,140 mm (45 in) of rain annually, with the Atlantic shore receiving 1,400 mm (55 in) or more. Most of the provincereceives about 1,900 mm (about 70 in) of snow, and considerable winter precipitation comes in the form of rain or ice storms. The average temperature in January, thecoldest month, is generally about -4°C (about 25°F) near the coast and somewhat colder toward the interior. The average temperature in July, the hottest month, isabout...

• Nova Scotia - Canadian History.

  summer. Nova Scotia receives an average of more than 1,140 mm (45 in) of rain annually, with the Atlantic shore receiving 1,400 mm (55 in) or more. Most of the provincereceives about 1,900 mm (about 70 in) of snow, and considerable winter precipitation comes in the form of rain or ice storms. The average temperature in January, thecoldest month, is generally about -4°C (about 25°F) near the coast and somewhat colder toward the interior. The average temperature in July, the hottest month, isabout...

• Beijing - geography.

  other polluting materials contributes to the city’s severe air and water pollution. V EDUCATION AND CULTURE Beijing has more colleges and universities than any other Chinese city. The most prominent institutions are Peking University, founded in 1898; and Tsinghua University,founded in 1911, which is the most prestigious scientific and technical institution in the country. Both institutions are located in the northwest suburbs, an areaassociated with higher education and research. Also in this...

• américaine, littérature.

  le moi, la nature et la mort, se situe entre la tradition romantique américaine et la tradition calviniste de la Nouvelle-Angleterre. 3. 2 La guerre de Sécession américaine et la fin du XIX e siècle Non sans humour, Abraham Lincoln parlait de l’auteur de la Case de l’oncle Tom (1852), Harriet Beecher-Stowe, comme de « la petite femme qui a provoqué cette grande guerre ». Plus qu’une grande œuvre littéraire, ce roman fut surtout l’expression du profond sentiment abolitionniste des Nordistes....

• Cuban Missile Crisis.

  inspect ships to determine whether they were carrying weapons. Kennedy warned that if Khrushchev fired missiles from Cuba, the result would be “a full retaliatoryresponse upon the Soviet Union.” Because international law defines a blockade as an act of war, Kennedy and his advisers decided to refer to the blockade as a quarantine. The United States wassupported by other members of the Organization of American States, an organization of nations in the western hemisphere that seek to cooperate on...

• Cuban Missile Crisis - U.

  inspect ships to determine whether they were carrying weapons. Kennedy warned that if Khrushchev fired missiles from Cuba, the result would be “a full retaliatoryresponse upon the Soviet Union.” Because international law defines a blockade as an act of war, Kennedy and his advisers decided to refer to the blockade as a quarantine. The United States wassupported by other members of the Organization of American States, an organization of nations in the western hemisphere that seek to cooperate on...

• espaces et échanges

• Turbine.

  steam turbine has supplanted the reciprocating engine as a prime mover in large electricity-generating plants and is also used as a means of jet propulsion. Steam turbines are used in the generation of nuclear power and in nuclear ship propulsion. They operate with fuel-fired boilers for power generation. In cogenerationapplications requiring both process heat (heat used in an industrial process) and electricity, steam is raised at high pressure in the boiler and extracted from the turbineat th...

• Golf. I INTRODUCTION Golf, outdoor game in which individual players use specially designed

  caddie or caddy. (Caddies, once an integral feature of the game, have now been replaced on many courses by motorized carts and pull carts.) In England the game was made popular by the attention given it by James VI of Scotland, later James I of England, and his son Charles I. In the 18th century the first golf associations were established. They included the Honourable Company of Edinburgh Golfers (founded 1744) in Edinburgh, Scotland;the Saint Andrews Society of Golfers (1754) in Saint Andrew...

• Coronary Heart Disease.

  when a patient is at rest may indicate that the blood supply of the heart is not normal, and the ECG can often detect damage from a previous heart attack. In anexercise stress test, an ECG is recorded while a patient is performing physical activity such as walking on a treadmill or riding a stationary bicycle. As the intensity ofexercise increases, the doctor looks for specific changes in the ECG that indicate the heart is not getting enough oxygen. In cardiac catheterization, a long, thin, flex...

• Zachary Taylor.

  army fled back across the Río Grande into Mexico. When Polk got word of the victories, he promoted Taylor to major general. Congress awarded him two gold medals. B1 Battle of Monterrey In September 1846, Taylor began an invasion of northern Mexico. His army of 6000 consisted of regulars and volunteers. On September 21 he attacked the fortifiedcity of Monterrey, which was defended by more than 7000 Mexicans under General Pedro de Ampudia. Taylor divided his army, giving Brigadier General William...

• Zachary Taylor

  army fled back across the Río Grande into Mexico. When Polk got word of the victories, he promoted Taylor to major general. Congress awarded him two gold medals. B1 Battle of Monterrey In September 1846, Taylor began an invasion of northern Mexico. His army of 6000 consisted of regulars and volunteers. On September 21 he attacked the fortifiedcity of Monterrey, which was defended by more than 7000 Mexicans under General Pedro de Ampudia. Taylor divided his army, giving Brigadier General William...

• 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...

• Diseases of Animals.

  infected animal. It may also spread in milk or in garbage that contains contaminated meat. Typical symptoms include blisters that appear on the mouth and feet;animals may become lame when their hooves degenerate. Canine distemper is a highly contagious disease caused by the paramyxovirus, which is transmitted in discharges from the nose and eyes. Symptoms begin with fever,malaise, and nasal and ocular discharges and may progress to convulsions and other nervous system disorders. Parvoviruses aff...

• Rome (Italy) - geography.

  country’s best, and in the summer at the Baths of Caracalla. The city also has some 20 theaters and 6 major concert halls, which offer a varied repertory during the fall,winter, and spring. The museums of the city deal with all aspects of the arts and sciences and are among the world’s finest. The oldest art collection in Rome, housed in the CapitolineMuseum, was established in 1471 and contains exceptional antiquities. Among other Roman museums are the National Museum of the Villa Giulia, which...

• From Pride and Prejudice - anthology.

  But why Mr Darcy same so often to the Parsonage, it was more difficult to understand. It could not be for society, as he frequently sat there ten minutes togetherwithout opening his lips; and when he did speak, it seemed the effect of necessity rather than of choice—a sacrifice to propriety, not a pleasure to himself. He seldomappeared really animated. Mrs Collins knew not what to make of him. Colonel Fitzwilliam's occasionally laughing at his stupidity, proved that he was generallydifferent, wh...

• Influenza.

  days and disappear in seven to ten days. However, coughing and fatigue may persist for two or more weeks. Death from influenza itself is rare. But influenza can aggravate underlying medical conditions, such as heart or lung disease. Invading influenza viruses produceinflammation in the lining of the respiratory tract, damage that increases the risk that secondary infections will develop. Common complications include bronchitis,sinusitis, and bacterial pneumonia, occurring most frequently in olde...

• Buenos Aires (city) - geography.

  The city has produced or nurtured many of the most prominent Spanish-language writers of the 20th century, including Jorge Luis Borges, Julio Cortázar, and ManuelPuig. Buenos Aires has long been one of the primary centers of Spanish-language publishing and printing, and it is home to major publishing companies. It supports theoldest English-language daily newspaper in Latin America, the Buenos Aires Herald, published since 1876. The arts have a long, rich history in Buenos Aires. This is mani...

• Earth (planet).

  Milky Way to complete one revolution around the Galaxy’s center. Earth’s axis of rotation is inclined (tilted) 23.5° relative to its plane of revolution around the Sun. This inclination of the axis creates the seasons and causes the height of the Sun in the sky at noon to increase and decrease as the seasons change. The Northern Hemisphere receives the most energy from the Sun when it is tiltedtoward the Sun. This orientation corresponds to summer in the Northern Hemisphere and winter in the S...

• Earth (planet) - astronomy.

  Milky Way to complete one revolution around the Galaxy’s center. Earth’s axis of rotation is inclined (tilted) 23.5° relative to its plane of revolution around the Sun. This inclination of the axis creates the seasons and causes the height of the Sun in the sky at noon to increase and decrease as the seasons change. The Northern Hemisphere receives the most energy from the Sun when it is tiltedtoward the Sun. This orientation corresponds to summer in the Northern Hemisphere and winter in the S...

• Isaac NewtonIINTRODUCTIONIsaac Newton (1642-1727), English physicist, mathematician, and natural philosopher, considered one of the most important scientists of all time.

  B Calculus (Newton’s “Fluxional Method”) In 1669 Newton gave his Trinity mathematics professor Isaac Barrow an important manuscript, which is generally known by its shortened Latin title, De Analysi . This work contained many of Newton’s conclusions about calculus (what Newton called his “fluxional method”). Although the paper was not immediately published, Barrowmade its results known to several of the leading mathematicians of Britain and Europe. This paper established Newton as one of the...

• Isaac Newton.

  B Calculus (Newton’s “Fluxional Method”) In 1669 Newton gave his Trinity mathematics professor Isaac Barrow an important manuscript, which is generally known by its shortened Latin title, De Analysi . This work contained many of Newton’s conclusions about calculus (what Newton called his “fluxional method”). Although the paper was not immediately published, Barrowmade its results known to several of the leading mathematicians of Britain and Europe. This paper established Newton as one of the t...

• Jerusalem - geography.

  There are many other artifacts in the city, tied to various periods of history; those of Canaanite, Israelite, Greek, Roman, Arab, Crusader, and Ottoman origin areamong the more prominent. Modern attractions include the Israel Museum (completed in 1965), which houses the Shrine of the Book, where the Dead Sea Scrolls areexhibited; the Rockefeller Museum (opened in 1938), which contains archaeological finds; the Yad Vashem Holocaust Museum; the Museum of Biblical Archaeology; theMuseum of Islamic...

• Trinidad and Tobago - country.

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

• Les Inuits

• Shakespeare

• Optics I INTRODUCTION Mirage Mirages appear because differences in air temperature cause light rays from an object to take different paths to a viewer's eye.

  Refraction of Light by DiamondsThe brilliance of diamonds is due to their high refractive index, a measure of how strongly a transparent material bendslight rays. The skill of the gem-cutter lies in angling the facets of the stone so that each light ray entering it is reflectedmany times before it emerges again.Spencer Grant/Photo Researchers, Inc. The amount of light reflected depends on the ratio of the refractive indexes for the two media. The plane of incidence contains the incident ray and...

• HERNANI DE VICTOR HUGO (TEXTE)

• 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...

• Johann Sebastian Bach.

  from his duties, and even tossed him into jail for “too obstinately requesting his dismissal.” But after several weeks the duke saw it was of no use and let him go. E Köthen: 1717-1723 Bach’s new employer, Leopold, loved and understood music and could play the violin, viola da gamba, and harpsichord as well as sing bass. The prince held Bach in highregard and stood as godfather for his seventh child. Bach, in turn, named the child Leopold August in his employer’s honor. Bach later said that the...

• Paris (city, France) - geography.

  Théâtre Musical de Paris and the Théâtre de la Ville. Just north of the Hôtel de Ville is the Pompidou Center, also known as Beaubourg, an arts complex devoted to modern and contemporary art and design. The structure,in steel and glass and featuring brightly colored, exposed pipes and ducts, is the work of Italian architect Renzo Piano and British architect Richard Rogers. Itscontroversial pop-art design contrasts sharply with the overall gray hue of the city, and was criticized by many followin...

• LAIS MARIE DE FRANCE

  toujours d'accepter son identité jusqu'à ce qu'elle révèle la ceinture de chasteté. Elle lui dit alors de son voyage douloureux. Mériaduc tente de garder la reine sous son contrôle, mais il est contrarié et finalement tué par Guigemar. "Équitan" est un lai breton, un type de poème narratif, écrit par Marie de France dans le courant du 12ème siècle. Le poème fait partie de ce qui est collectivement connus comme Les Lais de Marie de France. Comme les autres lais dans la coll...

• Automobile.

  Electric motors have been used to power automobiles since the late 1800s. Electric power supplied by batteries runs the motor, which rotates a driveshaft, the shaftthat transmits engine power to the axles. Commercial electric car models for specialized purposes were available in the 1980s. General Motors Corporation introduced amass-production all-electric car in the mid-1990s. Automobiles that combine two or more types of engines are called hybrids. A typical hybrid is an electric motor with ba...

• Antarctica - Geography.

  The maximum area of sea ice surrounding Antarctica each winter varies from year to year. A marked decline during the 1970s appears to have reversed in more recentdecades, except in the Antarctic Peninsula area. This area has lost almost 40 percent of its sea ice since the start of the 1980s. Sea ice is important to marine life. Krillfeed on algae that live under the sea ice and are released when the ice melts in spring and summer. In turn, many marine animals feed on krill. Emperor penguinsbreed...