1657 résultats pour "havas"

• Guyana - country.

  European patterns of living. People of mixed African and European ancestry form a distinct group in Guyana, maintaining closer social ties to the European communitythan to the African Guyanese community. Asians from the Indian subcontinent began to arrive in the 19th century, following the abolition of slavery in Guyana, to work as indentured and contract laborers. Theycontinued to arrive until 1917, when Britain outlawed indentured servitude. Thousands of Indians chose to remain in Guyana after...

• Czech Republic - country.

  enforcement of environmental regulations. Environmental considerations have also led some government officials to promote nuclear energy as a key source of powerfor the country’s future. The Czech Republic produces most of its energy by burning domestic coal. Much of the coal burned is low quality with a high ash and sulfur content—a key componentof acid rain—producing high levels of air pollution. Forests in the Czech Republic are among the most seriously affected by acid rain in all of Europe....

• Anxiety.

  A Genetics and Neurobiology Studies suggest that anxiety disorders run in families. That is, children and close relatives of people with disorders are more likely than most to develop anxietydisorders. Some people may inherit genes that make them particularly vulnerable to anxiety. These genes do not necessarily cause people to be anxious, but the genesmay increase the risk of anxiety disorders when certain psychological and social factors are also present. Anxiety also appears to be related to...

• Ghana - country.

  times of depressed cacao prices, Ghana has significantly increased exports of timber to generate needed revenue. In 1988 Ghana initiated a conservation plan called the Forest Resource Management Project. In 1989 Ghana restricted the export of 18 tree species, and in 1994 thecountry banned the export of raw logs. About 4.8 percent (1997) of the country’s land is officially protected, but illegal logging threatens Ghana’s remaining forests. Deforestation, overgrazing, and periodic drought have led...

• Radar.

  gathers the weak returning radar signals and converts them into an electric current. Because a radar antenna may both transmit and receive signals, the duplexerdetermines whether the antenna is connected to the receiver or the transmitter. The receiver determines whether the signal should be reported and often does furtheranalysis before sending the results to the display. The display conveys the results to the human operator through a visual display or an audible signal. B1 The Antenna The rec...

• 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...

• Nebraska - geography.

  by natural resource districts to limit the rate of pumping for irrigation. C Climate Nebraska has a typical continental climate with wide seasonal variations in temperature. C1 Temperature Winter temperatures below -20°C (0° F) and summer temperatures in the upper 30°s C (lower 100°s F) are common. The average January temperature varies from about -7° C (about 20° F) in the northeast to about -2° C (about 29° F) in the southwest. The average for July, thehottest month, ranges from about 26° C...

• Nebraska - USA History.

  by natural resource districts to limit the rate of pumping for irrigation. C Climate Nebraska has a typical continental climate with wide seasonal variations in temperature. C1 Temperature Winter temperatures below -20°C (0° F) and summer temperatures in the upper 30°s C (lower 100°s F) are common. The average January temperature varies from about -7° C (about 20° F) in the northeast to about -2° C (about 29° F) in the southwest. The average for July, thehottest month, ranges from about 26° C...

• Madrid - geography.

  stores and offices on the first one or two levels. While many people rent their apartments, most own them and participate in cooperatives that maintain the building.Because living spaces are small by American standards, madrileños do most of their socializing in the streets, bars, restaurants, and parks of their neighborhoods. Onlya few very wealthy areas north of the city have single family houses with gardens and yards similar to those in American suburbs. Many of the newest neighborhoodsare c...

• Endocrine System.

  thermostat. When the heat in a house falls, the thermostat responds by switching the furnace on, and when the temperature is too warm, the thermostat switches thefurnace off. Usually, the change that a hormone produces also serves to regulate that hormone's secretion. For example, parathyroid hormone causes the body toincrease the level of calcium in the blood. As calcium levels rise, the secretion of parathyroid hormone then decreases. This feedback mechanism allows for tight controlover hormon...

• Native American Architecture I INTRODUCTION Native American Architecture, traditional architecture of the peoples of who lived in North America before Europeans arrived.

  Mound Builders who resided in the area.John Elk III/Bruce Coleman, Inc. Another mound building culture, named Hopewell, also appears to have originated in Ohio but expanded west to Iowa, Kansas, and Oklahoma, south to Louisiana,Mississippi, and Alabama, east to Georgia and the Appalachian Mountains, and north to Wisconsin, Michigan, and lower Ontario in Canada. The Hopewell culture lastedfrom about 200 BC to 400 AD. Hopewell people built large, linear mounds to create enclosures in geometrical...

• Excerpt from Romeo and Juliet - anthology.

  Take all myself. ROMEO. I take thee at thy word.Call me but love, and I’ll be new baptized.Henceforth I never will be Romeo. JULIET. What man art thou that, thus bescreened in night,So stumblest on my counsel? ROMEO. By a nameI know not how to tell thee who I am.My name, dear saint, is hateful to myself,Because it is an enemy to thee.Had I it written, I would tear the word. JULIET. My ears have yet not drunk a hundred wordsOf thy tongue’s uttering, yet I know the sound.Art thou not Romeo, and a...

• Greece - country.

  minerals, such as chromium, copper, uranium, and magnesium, are relatively small. Greece’s small petroleum deposits, located under the Aegean Sea near the island ofThásos, are rapidly being depleted. There are no significant reserves of natural gas. Greece’s forests, probably abundant in ancient times, have been significantly depleted. Subsequent soil erosion has made reforestation efforts difficult. Although muchof Greece’s soil is rocky and dry, the country’s mountains are interspersed with sm...

• London (England) - geography.

  In the northern part of the West End is Bloomsbury, the city’s traditional intellectual center, with its concentration of bookshops and homes of writers and academics. Inthe early 20th century a number of famous writers, critics, and artists who lived here became known as the Bloomsbury Group. Here, too, is the British Museum, one ofLondon’s chief tourist attractions. Nearby is the giant complex of the University of London, whose various colleges and departments have taken over much ofBloomsbury...

• Central America - Geography.

  F Animal Life Most of the animal life of Central America is similar to that of South America, but some animals have ties with North America. The marley and opossum have links withSouth America, as do the jaguar, ocelot, jaguarundi, and margay, which are members of the cat family. In contrast, the puma, gray fox, and coyote are of NorthAmerican origin. The armadillo, anteater, and sloth have ties to the south, deer to the north. The large manatee, an aquatic plant eater, survives in the isolated...

• Invertebrate - biology.

  animals with a five-pointed design. They live in the sea and move with the help of tiny fluid-filled feet—another feature found nowhere else in the animal world. Zoologists recognize several different groups of worms. The phylum known as flatworms contains the simplest animals possessing heads. Nerves and sense organs areconcentrated in the head. Most flatworms are paper-thin and live in a variety of wet or damp habitats, including the digestive systems of other animals. Roundwormsrepresent anot...

• Invertebrate - biology.

  animals with a five-pointed design. They live in the sea and move with the help of tiny fluid-filled feet—another feature found nowhere else in the animal world. Zoologists recognize several different groups of worms. The phylum known as flatworms contains the simplest animals possessing heads. Nerves and sense organs areconcentrated in the head. Most flatworms are paper-thin and live in a variety of wet or damp habitats, including the digestive systems of other animals. Roundwormsrepresent anot...

• Islam.

  commanded to face the Kaaba, an ancient shrine in the city of Mecca. The Qur’an also refers to the recitation of parts of the Qur’an as a form of prayer. However, evenwith its numerous references, the Qur’an alone does not give exact instructions for this central ritual of prayer. The most detailed descriptions of the rituals for prayer derive from the example set by the prophet Muhammad and are preserved in later Islamic traditions. Somedetails of these rituals vary, however all Muslims agree t...

• Turkmenistan - country.

  A Ethnic Groups With Turkmens constituting 77 percent of the population, Turkmenistan is the most ethnically homogeneous of the Central Asian republics. Uzbeks make up the largestminority group, with about 9 percent of the population. Other ethnic groups include Russians, Kazakhs, Tatars, Ukrainians, Azeris (ethnic Azerbaijanis), Armenians, andBaluch. In 1993 a bilateral treaty between Turkmenistan and Russia granted dual citizenship to Russians in the republic. At the 1995 census Russians cons...

• Egypt - country.

  Egypt has a wide variety of mineral deposits, some of which, such as gold and red granite, have been exploited since ancient times. The chief mineral resource ofcontemporary value is petroleum, found mainly in the Red Sea coastal region, at Al ‘Alamayn (El ‘Alamein) on the Mediterranean, and on the Sinai Peninsula. Otherminerals include phosphates, manganese, iron ore, and uranium. Natural gas is also extracted. D Plants and Animals The vegetation of Egypt is confined largely to the Nile Delta,...

• Hurricane.

  V HOW HURRICANES ARE DETECTED AND MONITORED Since 1943 U.S. military and civilian aircraft have been flying into hurricanes to measure wind velocities and directions, the location and size of the eye, air pressures,and temperatures in different parts of the storm. A coordinated system of tracking hurricanes was developed in the mid-1950s, and steady improvements have beenmade over the years. In addition to reports from aircraft, geosynchronous weather satellites (since 1966) and ocean buoys tha...

• New York - geography.

  The Adirondack province consists of a large highland area occupying 26,000 sq km (10,000 sq mi) in the northeastern quarter of the state. The region is domelike inshape, with the higher elevations toward the east. The western Adirondack province is more a rugged hill region and not truly mountainous. Geologically, this area isrelated to the Laurentian Upland, or Canadian Shield, which lies north of the St. Lawrence River, for it is composed of the same very old igneous rocks, principallygranite...

• New York - USA History.

  The Adirondack province consists of a large highland area occupying 26,000 sq km (10,000 sq mi) in the northeastern quarter of the state. The region is domelike inshape, with the higher elevations toward the east. The western Adirondack province is more a rugged hill region and not truly mountainous. Geologically, this area isrelated to the Laurentian Upland, or Canadian Shield, which lies north of the St. Lawrence River, for it is composed of the same very old igneous rocks, principallygranite...

• From Julius Caesar - anthology.

  Let but the commons hear this testament—Which, pardon me, I do not mean to read—And they would go and kiss dead Caesar's wounds,And dip their napkins in his sacred blood,Yea, beg a hair of him for memory,And, dying, mention it within their wills,Bequeathing it as a rich legacyUnto their issue.FIFTH PLEBEIAN : We'll hear the will. Read it, Mark Antony. ALL THE PLEBEIANS : The will, the will! We will hear Caesar's will. ANTONY : Have patience, gentle friends, I must not read it. It is not meet you...

• Excerpt from Much Ado About Nothing - anthology.

  BEATRICE. Alas, he gets nothing by that. In our last conflict four of his five wits went halting off, and now is the whole man governed with one; so that if he havewit enough to keep himself warm, let him bear it for a difference between himself and his horse; for it is all the wealth that he hath left, to be known a reasonablecreature. Who is his companion now? He hath every month a new sworn brother. MESSENGER. Is't possible? BEATRICE. Very easily possible: he wears his faith but as the fashio...

• Shrimp - biology.

  shrimp have a maximum length of about 20 cm (8 in). On the West Coast, the Franciscan Bay shrimp is caught commercially. Freshwater shrimp are most common in warm parts of the world. They include river shrimp, edible shrimp that are trapped or farmed in the tropics, and also all trueshrimp that have become adapted for life in caves. Cave shrimp are typically pale, with vestigial (nonfunctioning) eyes, and they find their way mainly by touch. Decapod shrimp also include animals that are rarely ea...

• Checks and Balances.

  no political interest has enough power to prevail over the others. In 1997 and early 1998, for example, the Senate refused to take action on many of President BillClinton’s appointments of new federal court judges. Although the Senate’s power to approve or reject federal court nominees is one of the key checks on presidentialauthority, the dispute between Clinton and the Senate meant that there were not enough federal judges to handle the court’s workload. But the system of checks andbalance was...

• From Bulfinch's Mythology: Bacchus (Dionysus) - anthology.

  me their fishing rods and nets and their fisherman's trade. This I followed for some time, till growing weary of remaining in one place, I learned the pilot's art and howto guide my course by the stars. It happened as I was sailing for Delos we touched at the island of Dia and went ashore. Next morning I sent the men for fresh water,and myself mounted the hill to observe the wind; when my men returned bringing with them a prize, as they thought, a boy of delicate appearance, whom they hadfound a...

• Amphibian (animal) - biology.

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

• From "Resistance to Civil Government" - anthology.

  intending it, as God. A very few—as heroes, patriots, martyrs, reformers in the great sense, and men—serve the state with their consciences also, and so necessarily resist it for the most part; and they are commonly treated as enemies by it. A wise man will only be useful as a man, and will not submit to be “clay,” and “stop a holeto keep the wind away,” but leave that office to his dust at least: “I am too high born to be propertied,To be a second at control,Or useful serving-man and instr...

• 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...

• 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...

• Personality Disorders.

  People with histrionic personality disorder constantly strive to be the center of attention. They may act overly flirtatious or dress in ways that draw attention. They may also talk in a dramatic or theatrical style and display exaggerated emotional reactions. F Narcissistic Personality Disorder People with narcissistic personality disorder have a grandiose sense of self-importance. They seek excessive admiration from others and fantasize about unlimited success or power. They believe they...

• Reproductive System.

  in which the young develop, and a thinner channel, the vagina, which opens exteriorly. V GENITALS In animals that lay their eggs and discharge their sperm into water, the spermatozoa reach the eggs by chemical attraction; the eggs of individuals of a species attractonly the sperm of members of the same species. When eggs and sperm are deposited at great distances from each other, the number of eggs fertilized is small. Manyamphibians and aquatic vertebrates solve this problem by attaching thems...

• Yangtze - Geography.

  A Agriculture and Industry Today about 400 million people, or about one-third of the population of China, live in the Yangtze Basin. Many are engaged in agriculture. The basin contributes nearlyhalf of China’s crop production, although only one-quarter of the basin is arable. The most fertile areas for farming are the Sichuan Basin, the plains between theYangtze and its tributary the Han, and the plains of the lower basin. In all about 40 percent of the cereals, more than 30 percent of the cott...

• Whale - biology.

  III BEHAVIOR OF WHALES Studies of whales in captivity have taught scientists much about the complex social behavior of whales. Since the late 1980s, advances in the use of satellite trackingsystems have also broadened opportunities for scientists to observe how whales behave in the wild. A Swimming and Diving Whales swim by making powerful up-and-down movements of the tail flukes, which provide thrust. The power comes from body muscles that flex the lower spine upand down in a wavelike motion...

• Excerpt from Dombey and Son - anthology.

  light. Rivers and seas were formed to float their ships; rainbows gave them promise of fair weather; winds blew for or against their enterprises; stars and planetscircled in their orbits, to preserve inviolate a system of which they were the centre. Common abbreviations took new meanings in his eyes, and had sole reference tothem. A.D. had no concern with anno Domini, but stood for anno Dombei—and Son. He had risen, as his father had before him, in the course of life and death, from Son to D...

• 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...

• Persian Gulf War.

  to “use all necessary means” to force Iraq from Kuwait if Iraq remained in the country after January 15, 1991. The Iraqis rejected the ultimatum. Soon after the vote,the United States agreed to a direct meeting between Secretary of State James Baker and Iraq’s foreign minister. The two sides met on January 9. Neither offered tocompromise. The United States underscored the ultimatum, and the Iraqis refused to comply with it, even threatening to attack Israel. For the United States, themeeting was...

• Persian Gulf War - History.

  to “use all necessary means” to force Iraq from Kuwait if Iraq remained in the country after January 15, 1991. The Iraqis rejected the ultimatum. Soon after the vote,the United States agreed to a direct meeting between Secretary of State James Baker and Iraq’s foreign minister. The two sides met on January 9. Neither offered tocompromise. The United States underscored the ultimatum, and the Iraqis refused to comply with it, even threatening to attack Israel. For the United States, themeeting was...

• Persian Gulf War - U.

  to “use all necessary means” to force Iraq from Kuwait if Iraq remained in the country after January 15, 1991. The Iraqis rejected the ultimatum. Soon after the vote,the United States agreed to a direct meeting between Secretary of State James Baker and Iraq’s foreign minister. The two sides met on January 9. Neither offered tocompromise. The United States underscored the ultimatum, and the Iraqis refused to comply with it, even threatening to attack Israel. For the United States, themeeting was...

• Shark - biology.

  Sharks have two-chambered hearts that are relatively small compared to the rest of their bodies. Blood flows from the heart to the gills, where it collects oxygen fromwater and then distributes it to the other organs and tissues. The small heart produces weak blood pressure, and many sharks must swim continuously to create themuscular contractions needed to circulate blood throughout their bodies. Most sharks are cold-blooded—that is, they do not generate heat by digesting food. Instead, the bod...

• Air Pollution.

  Several pollutants attack the ozone layer. Chief among them is the class of chemicals known as chlorofluorocarbons (CFCs), formerly used as refrigerants (notably in airconditioners), as agents in several manufacturing processes, and as propellants in spray cans. CFC molecules are virtually indestructible until they reach thestratosphere. Here, intense ultraviolet radiation breaks the CFC molecules apart, releasing the chlorine atoms they contain. These chlorine atoms begin reacting withozone, br...

• Ethnic Groups in Canada - Canadian History.

  Ontario and the Atlantic provinces (Nova Scotia, New Brunswick, Newfoundland and Labrador, and Prince Edward Island). Most of the Irish live in rural areas of NovaScotia, New Brunswick, Prince Edward Island, Ontario, and Québec. The Welsh are by far the smallest group among the British Canadians, and they have also settled inthe Atlantic provinces and Ontario. B Culture The language spoken by British Canadians is mostly English, but some Welsh speak their own Celtic language and some Scots, Gae...

• Intelligence.

  education. Teachers had no way of knowing which of the “slow” students had true learning problems and which simply had behavioral problems or poor prior education.In 1904 the French Ministry of Public Instruction asked Binet and others to develop a method to objectively identify children who would have difficulty with formaleducation. Objectivity was important so that conclusions about a child’s potential for learning would not be influenced by any biases of the examiner. The governmenthoped tha...

• Sexually Transmitted Infections.

  D Genital Herpes Genital herpes is caused by infection with the herpes simplex virus (HSV). Most cases of genital herpes are due to HSV type 2. Some cases, however, result from genitalinfections with HSV type 1, a common cause of cold sores. Genital herpes causes recurrent outbreaks of painful sores on the genitals, although the disease oftenremains dormant with no symptoms for long periods. In the United States, one in five individuals over the age of 12 is infected with HSV type 2, and the va...

• Classification - biology.

  species based on the fewest number of shared changes that have occurred from generation to generation. IV HISTORY OF CLASSIFICATION SYSTEMS Classification is one of the oldest sciences, but despite its age it is still a vigorous field full of new discoveries and methods. Much like other fields of science, greatthinkers have shaped the course of classification. One of the earliest classification schemes was established by Greek philosopher Aristotle, who lived in the 300s BC. Aristotle believe...

• Global Warming.

  some of the warming influence of increasing greenhouse gases. A1 Carbon Dioxide Carbon dioxide is the second most abundant greenhouse gas, after water vapor. Carbon dioxide constantly circulates in the environment through a variety of naturalprocesses known as the carbon cycle. It is released into the atmosphere from natural processes such as eruptions of volcanoes; the respiration of animals, whichbreathe in oxygen and exhale carbon dioxide; and the burning or decay of plants and other organic...

• Folk Art I INTRODUCTION Carved Native American Figure This figure of a Native American trapper was carved from a single pine log (about 1850-1890).

  that young Native American women were taught to weave by Ursuline nuns. The overall spirit of French-Canadian folk art is colorful, happy, and, at the same time,devout. B Anglo-Canadian Folk Art The English tradition in the Maritime provinces is strong in the decoration of utilitarian objects, in graining, marbling, and incising, and in ship carvings (both figureheadsand stern-board decorations). The emigration to Canada of many New Englanders during and after the American Revolution led to int...

• Extreme Sports.

  racing events are the Raid Gauloises and the Eco-Challenge. Created in 1989 by French journalist Gerard Fusil, the Raid Gauloises is a grueling two-week adventure racein which five-person teams cross rugged and remote terrain. The inaugural Raid was held in New Zealand, and subsequent races have been staged in Costa Rica,Madagascar, Borneo, and Chile. The race has five separate stages designed to fit each location’s unique terrain. Stages may require horseback riding, white-waterpaddling, mounta...