94 résultats pour "irrigation"
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irrigation.
surtout, pratiquent une variante de cette méthode : on recueille les eaux de pluie très abondantes de la saison humide dans de petites vallées fermées par un barrage. L'irrigation par puits est également très répandue. Le mode de distribution de l'eau dépend de plusieurs facteurs, en particulier de la pente. La submersion exige souvent l'aménagement de terrasses ou la construction de digues. Sur les pentes raides, on peut procéder par infiltration : l'eau ne recouvre plus le terrain ; elle cir...
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La micro-irrigation
2 Randriambelo Antsa Ny Ala Tessie Rabearivazaha Andoniaina Francky Introduction Actuellement, le monde subit un changement climatique. A Madagascar , comme dans le reste du monde, ces aléas occasionnent des conséquences désastreuses à cause du réchauffement de la planète et des activités humaines. Dans la grande île, où plus de 75% de la population dép end de l’agriculture, certaines régions sont confrontées au manque d’eau qui entraîne la chute de la production loc...
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irrigation - agriculture et agroalimentaire.
an au cours du dernier quart de ce siècle parce que les possibilités économiquement viables d'irrigation à grande échelle ont déjà été exploitées. D'autre part, comme lademande s'accroît pour des ressources hydriques limitées, l'utilisation judicieuse des surfaces disponibles et des ressources souterraines est aujourd'hui fondamentale. Enconséquence, l'irrigation est devenue un domaine très technique nécessitant la compilation de nombreuses données sur les ressources globales, la qualité du sol...
- Encyclopédie: Irrigation (Géographie)
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Cas des projets d'irrigation
PROJET DE D’IRRIGATION Etude de cas 1 Elaboration d’un projet de riziculture aquatique dans un bas-fond. 1) INTRODUCTION La communauté villageoise de Suibonou-Sakassou dans la région de Yamoussoukro veut exploiter son bas-fond. La superficie emblavable est 400ha. Il s’agit d’assurer en contre saison une production de riz en suivant la méthode d’alimentation hydrique optimale dite « apportévacuation ». 2) FACTEURS PHYSIQUES NATURELS 2.1. Localisation La zone concernée est située à 8...
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Idaho - geography.
Idaho-Montana state line in the southern part of the Bitterroot Mountains. Consequently, nearly all the rivers in the state drain toward the Pacific. Most of Idaho lieswithin the drainage basin of the Columbia River system. The Snake River, which is the chief river in southern and central Idaho, follows a crescent-shaped course forabout 790 km (about 490 mi) across southern Idaho. It then swings northward along the Idaho state line and joins the Columbia River in Washington. Major tributariesof...
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Idaho - USA History.
Idaho-Montana state line in the southern part of the Bitterroot Mountains. Consequently, nearly all the rivers in the state drain toward the Pacific. Most of Idaho lieswithin the drainage basin of the Columbia River system. The Snake River, which is the chief river in southern and central Idaho, follows a crescent-shaped course forabout 790 km (about 490 mi) across southern Idaho. It then swings northward along the Idaho state line and joins the Columbia River in Washington. Major tributariesof...
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India - country.
delta in the north, are intensely farmed. B Rivers and Lakes The rivers of India can be divided into three groups: the great Himalayan rivers of the north, the westward-flowing rivers of central India, and the eastward-flowingrivers of the Deccan Plateau and the rest of peninsular India. Only small portions of India’s rivers are navigable because of silting and the wide seasonal variation inwater flow (due to the monsoon climate). Water transport is thus of little importance in India. Barrages,...
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agriculture - agriculture et agroalimentaire.
de travailler vite et dans les meilleures conditions. Le travail de récolte, fondamental puisque une année d’efforts peut être ruinée ou récompensée, a connu la même évolution : récolte manuelle nécessitant des équipesnombreuses employées de façon temporaire, machines à traction animale comme la moissonneuse-lieuse, machines à traction mécanique, puis automotrices (comme lamoissonneuse-batteuse). La contrepartie de cette mécanisation est la nécessité de confier de grandes surfaces à ces machines...
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Wyoming (state) - geography.
The basins, which lie in the rain shadow of mountains, are very dry, with an average annual precipitation of about 250 mm (about 10 in) or less; the Great Plains regionhas an annual average of about 380 mm (about 15 in), and the Black Hills region receives slightly more. Thunderstorms and hailstorms are relatively frequent insummer. The annual snowfall ranges from about 500 mm (about 20 in) in the Bighorn Basin to well over 5,100 mm (over 200 in) in the higher mountains, where annualprecipitatio...
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Wyoming (state) - USA History.
The basins, which lie in the rain shadow of mountains, are very dry, with an average annual precipitation of about 250 mm (about 10 in) or less; the Great Plains regionhas an annual average of about 380 mm (about 15 in), and the Black Hills region receives slightly more. Thunderstorms and hailstorms are relatively frequent insummer. The annual snowfall ranges from about 500 mm (about 20 in) in the Bighorn Basin to well over 5,100 mm (over 200 in) in the higher mountains, where annualprecipitatio...
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Australia - country.
itself forms most of the border between New South Wales and Victoria. Considerable lengths of the Murray, Darling, and Murrumbidgee rivers are navigable during thewet seasons. The central plains region, also known as the Channel Country, is interlaced by a network of rivers. During the rainy season these rivers flood the low-lying countryside,but in dry months they become merely a series of water holes. The Victoria, Daly, and Roper rivers drain a section of the Northern Territory. In Queensland...
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Australia - Geography.
itself forms most of the border between New South Wales and Victoria. Considerable lengths of the Murray, Darling, and Murrumbidgee rivers are navigable during thewet seasons. The central plains region, also known as the Channel Country, is interlaced by a network of rivers. During the rainy season these rivers flood the low-lying countryside,but in dry months they become merely a series of water holes. The Victoria, Daly, and Roper rivers drain a section of the Northern Territory. In Queensland...
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Nile - Geography.
The Nile is also a source of hydroelectric power ( see Waterpower), although the river’s potential as a source of electricity has yet to be fully exploited. Dams to provide hydroelectricity (and control flooding) have been constructed along the Nile in Egypt, Sudan, and Uganda. Additional hydroelectric projects are planned. IV HISTORY OF THE NILE A Ancient Egypt and the Nile The first great African civilization developed in the northern Nile Valley in Egypt in about 3300 BC. Settlements alon...
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Les Politiques agraires dans le monde
, COUPE D'UN POLDER HOllANDAIS ' Une surface de 2250 knr a été reconquise sur la baie du Zuiderzee aux Pays-Bas. digu es . Un e fois d essal és, le s sols deviennent ainsi des terr es f e rtiles sur lesqu elles p e u vent s'impl anter de nouv ell es ferm e s et d es c hamps . Ces digues reliées entr e e lles prot ège nt une g ra nde parti e des Pays-B a s. Grâce à un systè m e de pompage perman ent, drainant l'eau salée, ces terres rest...
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Iraq - country.
The Euphrates begins in Turkey, crosses Syria, and enters Iraq at Abū Kam āl. The flow of the Euphrates into Iraq has been greatly reduced by dams built by Turkeyand Syria. The gradient of the Euphrates above the town of H īt, in west central Iraq, is steep. In the 2,640 km (1,640 mi) from its source in Turkey to H īt, the river fallsfrom 3,000 m (10,000 ft) to a low water elevation of 50 m (170 ft) above sea level, an average drop of 1 m per km (6 ft per mi). In Iraq below H īt the fall is very...
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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...
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Arizona - geography.
of the Mogollon Rim, the Little Colorado draws very little water from a relatively large watershed, usually containing a mere trickle of water in its riverbed. The ColoradoRiver’s principal tributary is the Gila River, which flows all the way across the southern part of the state from New Mexico to the California border. From the mountainsand plateaus of central Arizona, the Gila River receives the Salt, Agua Fria, and Hassayampa rivers. The Salt River is itself fed by the Verde River. The Gila...
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Arizona - USA History.
of the Mogollon Rim, the Little Colorado draws very little water from a relatively large watershed, usually containing a mere trickle of water in its riverbed. The ColoradoRiver’s principal tributary is the Gila River, which flows all the way across the southern part of the state from New Mexico to the California border. From the mountainsand plateaus of central Arizona, the Gila River receives the Salt, Agua Fria, and Hassayampa rivers. The Salt River is itself fed by the Verde River. The Gila...
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Brazil - country.
occasional droughts. Brazil contains a wealth of mineral and plant resources that have not yet been fully explored. It possesses some of the world’s largest deposits of iron ore and containsrich deposits of many other minerals, including gold and copper. Brazil’s fossil fuel resources are modest, but this limitation is offset by the considerable hydroelectricpotential of the nation’s many rivers. Although Brazil is an important producer of tropical crops, areas of highly fertile land are limited...
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Uzbekistan - country.
E Environmental Issues The evaporation of the Aral Sea is one of the worst ecological disasters in the world. The Aral has shrunk so much that it now holds only about one-fifth the volume ofwater it held in 1960. The shrinkage is due to irrigation withdrawals from the Amu Darya and Syr Darya, a practice that began on a massive scale in the early 1960s aspart of the Soviet Union’s ill-conceived drive to increase cotton yields in Central Asia. Growing cotton in the naturally arid and saline soil...
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Colorado - geography.
Although the rivers of Colorado are navigable only by small boats, they are important as a source of irrigation water for use in Colorado and adjoining states. However,the water level of the rivers fluctuates seasonally and from year to year. The level is generally low in winter and high in spring and summer, during the runoff of meltedsnow from the mountains. Colorado has no large lakes of natural origin, but there are numerous small lakes in the mountains. The largest bodies of water in Colora...
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Colorado - USA History.
Although the rivers of Colorado are navigable only by small boats, they are important as a source of irrigation water for use in Colorado and adjoining states. However,the water level of the rivers fluctuates seasonally and from year to year. The level is generally low in winter and high in spring and summer, during the runoff of meltedsnow from the mountains. Colorado has no large lakes of natural origin, but there are numerous small lakes in the mountains. The largest bodies of water in Colora...
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Oregon - geography.
B Rivers and Lakes The Columbia River forms most of the Oregon-Washington boundary, and with its tributaries this great river drains a large portion of Oregon. From the point where theColumbia first touches the state, at Wallula Gap, the river runs in a shallow gorge, deepening as it approaches the Cascades. This part of the river once had manyrapids and falls, but is now navigable by large vessels because of dams and locks that have been built along much of its length. An important tributary o...
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Oregon - USA History.
B Rivers and Lakes The Columbia River forms most of the Oregon-Washington boundary, and with its tributaries this great river drains a large portion of Oregon. From the point where theColumbia first touches the state, at Wallula Gap, the river runs in a shallow gorge, deepening as it approaches the Cascades. This part of the river once had manyrapids and falls, but is now navigable by large vessels because of dams and locks that have been built along much of its length. An important tributary o...
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Colorado (river, North America) - Geography.
sometime between AD 1300 and 1400, but their descendants, the Hopi and Pueblo people, continue to farm and irrigate using the river's waters. The first European to visit the river was probably Spanish soldier and explorer Francisco de Ulloa, who explored the mouth of the Colorado in 1539. In 1540 and 1541another Spaniard, Francisco Vásquez de Coronado, traveled through much of the region around the Colorado River. An exploring party from the Coronado expedition,led by Garcia López de Cárdenas,...
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Conservation.
cancers, Hodgkin’s disease and leukemia. Unfortunately, human activities have greatly reduced biodiversity around the world. The 20th century encompasses one of the greatest waves of extinction, orelimination of species, to occur on the planet. The greatest threat to biodiversity is loss of habitat as humans develop land for agriculture, grazing livestock, industry,and habitation. The most drastic damage has occurred in the tropical rain forests, which cover less than seven percent of the Earth’...
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Afrique.
delta. Le Congo, avec ses 4 400 km, baigne une grande partie de l'Afrique centrale. Il naît en Zambie et coule vers le nord sous le nom de Lualaba. Il oblique vers l'ouest puis versle sud-ouest pour se jeter dans l'océan Atlantique. Le troisième grand fleuve africain, le Niger, en Afrique occidentale, est long d'environ 4 200 km ; son cours supérieur n'est navigable que pendant la saison des pluies. LeNiger, qui prend sa source sur le plateau du Fouta-Djalon, coule vers le nord et l'est en forma...
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Montana - geography.
(191 sq mi), is Montana’s largest lake, and the largest natural freshwater lake in the contiguous states west of the Mississippi River. C Climate Climatic regions in Montana coincide roughly with the two major physiographic regions. In western Montana, as compared with the eastern plains area, winters tend tobe milder while summers are cooler. Precipitation is more evenly distributed throughout the year in the west, and it is cloudier and somewhat more humid in all seasons.In addition, the grow...
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Montana - USA History.
(191 sq mi), is Montana’s largest lake, and the largest natural freshwater lake in the contiguous states west of the Mississippi River. C Climate Climatic regions in Montana coincide roughly with the two major physiographic regions. In western Montana, as compared with the eastern plains area, winters tend tobe milder while summers are cooler. Precipitation is more evenly distributed throughout the year in the west, and it is cloudier and somewhat more humid in all seasons.In addition, the grow...
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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...
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Han Dynasty - History.
However, these reforms faced serious opposition. The feudal barons formed an alliance and rebelled against Wang Mang. They were joined by members of the Liufamily, who were descended from Jingdi (Ching-ti), a former Han emperor, and a civil war followed. As the empire fell into disorder, militant secret societies formedarmed bands and attacked villages and towns. Wang Mang had believed that proper institutions would eventually bring peace to China, but in AD 23, an army led by the Liu clan brea...
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Libya - country.
junipers and mastic trees are found in the higher elevations. Only a few large mammals are found in Libya. Wildlife includes desert rodents, hyenas, gazelles, and wildcats. Eagles, hawks, and vultures are common. E Environmental Issues Libya has undertaken a number of major irrigation projects intended to ease the country’s water shortage. The most ambitious is the so-called Great Man-Made River(GMMR), a massive 25-year irrigation scheme begun in 1984. The GMMR is a vast water pipeline system d...
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Turkey - country.
has a general elevation of 900 to 1,500 m (3,000 to 5,000 ft) above sea level. The eastern highlands region is the most mountainous and rugged portion of Turkey; Mount Ararat (Ağrı Da ğı) is the highest peak in the country at 5,165 m (16,945ft). Many Christians and Jews believe it to be the same Mount Ararat mentioned in the Bible as the place where Noah’s ark came to rest. The eastern highlands are thesource for both the Tigris (Dicle) and Euphrates (Fir āt)—two of southwestern Asia’s principal...
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Israel (country) - country.
harbor in the northern part of the country, and Ashdod, an artificial deepwater port to the south, serve as the main seaports on the Mediterranean. The port of Elat onthe Gulf of Aqaba provides Israel’s only access to the Red Sea, making it extremely important to the country’s shipping interests. D Natural Resources Although much of Israel’s desert regions contain poor soils, the northern Negev, the coastal plains, and the interior valleys provide patches of productive soils. Anestimated 18 per...
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riz. n .m. ( Oryza sativa), plante herbacée de la
eau - Les usages de l'eau graminées irrigation plantes - Les plantes cultivées - Les plantes alimentaires tropiques - L'agriculture dans les pays tropicaux - L'agriculture vivrière Les médias riz - production mondiale de riz paddy Les livres agriculture - culture du riz en Asie, page 96, volume 1 agriculture - agriculture et élevage dans le monde, page 100, volume 1 Asie du Sud-Est - la culture du riz, page 375, volume 1 Bangladesh - rizières aux environs de Dacca, page 542, volum...
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Histoire, géographie et économie: ISRAËL
PROCHE-OR IENT ISRAËL PALESTINE jusqu'au 1947 MER Q � 0 ...... "' EGYPTE � ISRAËL 1948-1967 MER ""' � '( Q 0:: 0 EGYPTE 0:: 0 EGYPTE 1 venance d'Europe orientale et cen trale (Ashkénazes parlant le yid dish), ou d'Afriq ue du Nord et du Moyen-Orient (Séfarades). Ces quinze dernières années, quelque 10 000 Falashas (Juifs d'Éthiopie) et un nombre considérable de Russes ont émigré vers Israël. Les Juifs, nés en Israël (les Sabras), sont majo...
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Phoenix (city, Arizona) - geography.
The company’s irrigation system followed the network of canals that were built there by the Hohokam some 500 years earlier. In October 1870, several settlers foundedthe site of modern Phoenix. In recognition of the former Hohokam culture, settler Darrell Duppa likened the new community to the phoenix, a mythological bird thatconsumed itself by fire every 500 years and arose anew from the ashes. Thereafter, the group adopted Phoenix as the settlement’s name. Within a short time the areawas produc...
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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...
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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...
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Les techniques d'irrigation traditionnelles
>U NIL ote a vécu au rythme de ~ était divisée en trois "'ldation (akhet), allait de !mbre. La deuxième, la iait de la mi-novembre à 1eant de l'eau à la faveur labourer et semer. La r (shemou), était celle où ~nt, triaient le grain et 7ue d'eau ou de rigueur • d'irrigation se traduisait 'lent du pays et un • pouvoir central. Au -de là, il est courant d'asso cier des ch adoufs supe rp osés (deux et même trois), en b...
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Oklahoma - geography.
portion and the Panhandle are classified as a steppe, where precipitation, typically 250 to 500 mm (10 to 20 in), is the controlling characteristic. January is usually the coldest month with an average of about 3°C (38°F) and extremes from -33°C (-27°F), the lowest ever recorded, to 33°C (92°F). Summer arelong and hot with temperatures in the upper 30°s C (lower 100°s F) common from May until September across the state. The growing season varies from less than 180days in the western Panhandle to...
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Oklahoma - USA History.
portion and the Panhandle are classified as a steppe, where precipitation, typically 250 to 500 mm (10 to 20 in), is the controlling characteristic. January is usually the coldest month with an average of about 3°C (38°F) and extremes from -33°C (-27°F), the lowest ever recorded, to 33°C (92°F). Summer arelong and hot with temperatures in the upper 30°s C (lower 100°s F) common from May until September across the state. The growing season varies from less than 180days in the western Panhandle to...
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Nevada - geography.
The Truckee, Carson, and Walker rivers flow out of the Sierra Nevada, thread their way around several of the desert ranges, and also end in closed basins. The Walkerflows into Walker Lake, the Carson into Lahontan Reservoir. The major part of the Truckee’s flow is now diverted to Lahontan Reservoir, although as required by lawsome of it empties into Pyramid Lake. Because these three streams flow constantly, the lakes into which they empty never dry up. Winnemucca Lake formerly receivedoverflow w...
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Nevada - USA History.
The Truckee, Carson, and Walker rivers flow out of the Sierra Nevada, thread their way around several of the desert ranges, and also end in closed basins. The Walkerflows into Walker Lake, the Carson into Lahontan Reservoir. The major part of the Truckee’s flow is now diverted to Lahontan Reservoir, although as required by lawsome of it empties into Pyramid Lake. Because these three streams flow constantly, the lakes into which they empty never dry up. Winnemucca Lake formerly receivedoverflow w...
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Afghanistan - country.
D Climate Most of Afghanistan has a subarctic mountain climate with dry and cold winters, except for the lowlands, which have arid and semiarid climates. In the mountains and afew of the valleys bordering Pakistan, a fringe effect of the Indian monsoon, coming usually from the southeast, brings moist maritime tropical air in summer.Afghanistan has clearly defined seasons: Summers are hot and winters can be bitterly cold. Summer temperatures as high as 49°C (120°F) have been recorded in thenorth...
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Native Americans of Middle and South America.
A line that snakes across central Mexico near the Tropic of Cancer forms the northern boundary of Mesoamerica; north of this line rainfall sharply declines and theclimate is much drier. The ancient civilizations of Mesoamerica all arose and developed in the area between this line and the Guatemalan highlands far to the south. Richvolcanic soils are found throughout much of the region. A2 People and Languages Mesoamerica was a great melting pot, home to many peoples and interrelated cultures. In...
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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,...
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Cours complet sciences politiques
On peut envisager la question de l’ordre politique en étudiant les croyances religieuses. On peut aussi envisager l’ordre politique comme uns super structure (Karl Marx-rapport de forces). Enfin, on peut l’envisager à travers l’étude des institutions, qui contribue à produire et à reproduire un ordre politique. C’est la question de l’Etat comme institution. Dans certains pays l’Etat est une forme d’organisation parmi d’autres. Il faut donc le placer dans son contexte d’ém...
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Washington (state) - geography.
The crest of the Cascade Range divides Washington into two distinct climatic regions. The area west of the Cascades, which is exposed throughout the year to rain-bearing winds from the Pacific Ocean, has a temperate marine type of climate that is characterized by mild wet winters and cool summers. The Cascades prevent themoist air blowing in from the Pacific from reaching eastern Washington. The Rocky Mountains on the eastern border also represent a climatic barrier. As a result, thesevere winte...