272 résultats pour "africa"

• Guinea - country.

  Mining operations in 2004 yielded 16 million metric tons of bauxite, 468,400 carats of high-quality diamonds, and 16,000 kg (35,300 lb) of gold. Environmental concernsand political instability in neighboring Liberia have delayed exploitation of high-grade iron ore from Mount Nimba. In 1999 the national budget included $466 million in revenues and $414 million in expenditures. The unit of currency is the Guinean franc, which is divided into 100 centimes (3,644 francs equal U.S.$1; 2005 average...

• 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...

• Comoros - country.

  Since 1981 the currency has been the Comorian franc. The Comorian franc had a fixed exchange rate with the French franc of 50 to 1 until 1994, when the rate was changed to 75 Comorian francs to 1 French franc. In 2006, the Comorian franc exchanged at an average of 392 to U.S.$1. Transport between the islands is mostly by air, and there is an international airport at Hahaia on Njazidja where jets can land. Road networks have been built betweenmost of the main island settlements, but the mountai...

• The Gambia - country.

  The population of The Gambia (2008 estimate) is 1,735,464, making it one of the least populous countries of Africa. Still, the country has a fairly high overall populationdensity of 174 persons per sq km (449 per sq mi), and the population is increasing at a rate of 2.7 percent a year. Banjul, formerly called Bathurst, is the capital andonly seaport. The largest city is Serrekunda, a transportation hub and commercial center. B Religion and Language The great majority of the people of The Gambia...

• Medio ambiente - ciencias de la naturaleza.

  aproximadamente. Lo significativo de este cambio es que puede provocar un aumento de la temperatura de la Tierra a través del proceso conocido como efecto invernadero.El dióxido de carbono atmosférico tiende a impedir que la radiación de onda larga escape al espacio exterior; dado que se produce más calor y puede escapar menos, latemperatura global de la Tierra aumenta. Un calentamiento global significativo de la atmósfera tendría graves efectos sobre el medio ambiente. Aceleraría la fusión de l...

• Wilfrid Laurier.

  The Manitoba schools were the main issue in the 1896 election. Although the Catholic clergy campaigned against him, Laurier argued in Québec that he would obtainbetter terms for the Catholics by negotiating directly with the provincial government of Manitoba. “Hands off Manitoba” was an effective slogan in the other provinces aswell. A second issue was corruption in the Conservative Party, as a series of scandals had rocked the Bowell administration. Israel Tarte, a former Québec conservativewho...

• Wilfrid Laurier - Canadian History.

  The Manitoba schools were the main issue in the 1896 election. Although the Catholic clergy campaigned against him, Laurier argued in Québec that he would obtainbetter terms for the Catholics by negotiating directly with the provincial government of Manitoba. “Hands off Manitoba” was an effective slogan in the other provinces aswell. A second issue was corruption in the Conservative Party, as a series of scandals had rocked the Bowell administration. Israel Tarte, a former Québec conservativewho...

• 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’...

• Capital Punishment.

  deterrent effect. Capital punishment advocates note that because the death penalty is reserved for the most aggravated murders, the deterrent effect of capitalpunishment on such crimes may not be apparent in data on homicide rates in general. Supporters also urge that the conflicting results of various studies indicate thatthe deterrent effect of the death penalty cannot not be proven or disproven with any certainty. They maintain that in the absence of conclusive proof that the threat ofexecuti...

• Carbon - chemistry.

  Graphite is black and slippery and conducts electricity. In graphite, the atoms form planar, or flat, layers. Each layer is made up of rings containing six carbon atoms.The rings are linked to each other in a structure that resembles the hexagonal mesh of chicken wire. Each atom has three sigma bonds (with 120° between any two ofthe bonds) and belongs to three neighboring rings. The fourth electron of each atom becomes part of an extensive pi bond system. Graphite conducts electricity,because th...

• Alphabet I INTRODUCTION Bengali Script India developed a number of different writing systems over the course of its history.

  A Pictographic and Ideographic Systems Early systems of writing used pictures to represent things and then to represent the sounds of those things. Pictographic writing, in which a simplified picture of the sunstood for the word sun, was probably the first step toward a written language. Chinese began as a pictographic language. To represent abstract ideas, the Chinese writing system combined pictographs. For example, the pictographs for sun and tree were combined to represent the concept of...

• From Uncle Tom's Cabin - anthology.

  the evils of slavery from sketches like these, is not the half that could be told, of the unspeakable whole. In the northern states, these representations may, perhaps, be thought caricatures; in the southern states are witnesses who know their fidelity. What personalknowledge the author has had, of the truth of incidents such as here are related, will appear in its time. It is a comfort to hope, as so many of the world's sorrows and wrongs have, from age to age, been lived down, so a ti...

• 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...

• Olympic Games.

  the next decade nearly all the ISFs abolished the distinction between amateurs and professionals, accepting so-called open Games. One of the most visible examples of the policy change came in 1992, when professional players from the National Basketball Association (NBA) were permitted to play inthe Summer Games in Barcelona, Spain. Professionals from the National Hockey League (NHL) became eligible to participate beginning with the 1998 Winter Olympics inNagano, Japan. V CEREMONIES The Olymp...

• Ireland - country.

  F Plants and Animals Ireland’s animal life does not differ markedly from that of England or France. Over many centuries of human settlement almost all of Ireland’s natural woodlands werecleared, and indigenous animals such as bear, wolf, wildcat, beaver, wild cattle, and the giant Irish deer (a type of fallow deer) gradually disappeared. However, thehardy and versatile Connemara pony, Ireland’s only native pony breed, has been used by Irish farmers since prehistoric times. The great auk, or gar...

• Ancient Greece.

  The first culture of Aegean civilization on the Greek mainland is named Mycenaean for the palace at Mycenae on the Pelopónnisos. Scholars call the Mycenaeans the“earliest Greeks” because they are the first people known to have spoken Greek. Mycenaean culture developed later than Minoan. The ancestors of the Mycenaean people wandered onto the mainland from the north and the east from about 4000 to2000 BC, mixing with the people already there, and by about 1400 BC the Mycenaeans had become very...

• Ancient Greece .

  The first culture of Aegean civilization on the Greek mainland is named Mycenaean for the palace at Mycenae on the Pelopónnisos. Scholars call the Mycenaeans the“earliest Greeks” because they are the first people known to have spoken Greek. Mycenaean culture developed later than Minoan. The ancestors of the Mycenaean people wandered onto the mainland from the north and the east from about 4000 to2000 BC, mixing with the people already there, and by about 1400 BC the Mycenaeans had become very...

• Ancient Greece - USA History.

  The first culture of Aegean civilization on the Greek mainland is named Mycenaean for the palace at Mycenae on the Pelopónnisos. Scholars call the Mycenaeans the“earliest Greeks” because they are the first people known to have spoken Greek. Mycenaean culture developed later than Minoan. The ancestors of the Mycenaean people wandered onto the mainland from the north and the east from about 4000 to2000 BC, mixing with the people already there, and by about 1400 BC the Mycenaeans had become very...

• Botswana 1983-1984 Le Botswana abrite dans sa capitale Gaborone le siège de la SADCC (Southern Africa Development Coordination Conference, organisation...

  Botswana 1983-1984 Le Botswana abrite dans sa capitale Gaborone le siège de la SADCC (Southern Africa Development Coordination Conference, organisation économique qui regroupe les neuf États de la "ligne de front", créée pour faire face à la domination sud-africaine), mais demeure très dépendant de son voisin. Le président Quett Masire est tenu, de peur de représailles, de déclarer que son pays n'abrite pas de membres de l'ANC, tout en tolérant le transit de réfugiés. Le régime est dirigé par l...

• Deriva continental - geographia.

• Grietas y ruptura continental - geographia.

• Nelson Mandela.

• Nelson Mandela - history.

• African National Congress.

• Apartheid.

• Nelson Mandela.

• Nilo - geografía.

  Yann Arthus-Bertrand/Corbis Cuando confluye con éste el Baḩr al-Ghazal (‘río de las gacelas’), se forma el Ba ḩr al-Abyad o Nilo Blanco. Varios afluentes discurren por la región del Ba ḩr al-Ghazal. EnJartum, el Nilo Blanco recibe las aguas del Nilo Azul o Ba ḩr al-Azraq. Los nombres de Blanco y Azul provienen del color de las aguas en los respectivos tramos. El Nilo Azul, de 1.529 km de longitud, debe su caudal de agua principalmente al lago Tana, en las tierras altas de Etiopía, donde se le co...

• Deforestación - geografía.

  La deforestación que se realiza para obtener leña constituye un problema en las áreas más secas de África, el Himalaya y los Andes. La deforestación que se realiza para crear asentamientos, explotaciones mineras y petrolíferas es localmente significativa, en especial los programas de reasentamientopuestos en práctica, hasta hace poco, en Indonesia y Brasil, donde los habitantes de zonas superpobladas fueron reasentados por sus respectivos gobiernos en superficiesocupadas por bosques. La construc...

• Botsuana (república) - geografía.

  todo el mundo. Las ventas de diamantes generan más del 80% de los ingresos por exportaciones de Botsuana y han contribuido a que el país se alejara de una economíabasada en la agricultura. Las precipitaciones son irregulares y el país tiene tendencia a la sequía. Sólo el 0,67% (2003) del territorio de Botsuana es cultivable. Durante la década de 1980 seplanificó un gran proyecto de irrigación y almacenamiento de agua para la región norte del país, pero la conciencia medioambiental y la oposición...

• Burundi - geografía.

  Población de BurundiEl 89% de la población de Burundi es rural; la mayoría de la gente vive en grupos familiares dispersos por las regiones montañosas.Jean Gaumy/Magnum Photos La población era de 8.691.005 habitantes (según estimaciones para 2008), con una densidad de 339 hab/km², una de las más altas en África. La población es rural en un89%; la mayoría de la gente vive en grupos familiares dispersos por las regiones montañosas, mientras que el hábitat concentrado en pueblos es poco habitual. L...

• Malí - geografía.

  Terreno de Malí azotado por el vientoUna tormenta de viento envía asfixiantes nubes de polvo que ruedan por el terreno llano de Malí. La sequía es una amenazaconstante para este país cálido y seco situado en África occidental.Jeremy Hartlley/Panos Pictures El medio ambiente de Malí sufre las consecuencias de un rápido crecimiento de la población y de una continuada sequía que dura ya décadas. Malí tiene una de las tasasanuales de natalidad más altas del mundo, 49,40 nacimientos por cada 1.000 ha...

• Spanish Empire.

  Spain’s royal government quickly imposed its own officials, first to collect taxes and then to administer the colony. Its goal was to assert royal control over both settlersand indigenous peoples. In Spain the government established a House of Trade to supervise colonial affairs and to oversee, license, and tax all trade and commerce. Asthe royal government asserted more authority over colonial activities, Columbus lost effective power, and was eventually replaced by other colonial governors. Wi...

• Spanish Empire .

  Spain’s royal government quickly imposed its own officials, first to collect taxes and then to administer the colony. Its goal was to assert royal control over both settlersand indigenous peoples. In Spain the government established a House of Trade to supervise colonial affairs and to oversee, license, and tax all trade and commerce. Asthe royal government asserted more authority over colonial activities, Columbus lost effective power, and was eventually replaced by other colonial governors. Wi...

• Ruanda - geografía.

  Los principales recursos minerales son la casiterita (mineral de estaño), el tungsteno, el berilio y el oro. Actualmente las grandes reservas de gas natural descubiertas cercade la frontera con la República Democrática del Congo están en proceso de explotación. 2.4 Temas medioambientales Ruanda es uno de los países menos desarrollados y más pobres del mundo, en parte debido al conflicto étnico que ha bloqueado al país durante la década de 1990. Lainestabilidad política ha provocado interrupcion...

• Mozambique - geografía.

  desciende de los 1.422 mm en el norte hasta los 762 mm del sur. 2.4 Vegetación y fauna Elefante africanoLos grandes elefantes africanos (Loxodonta africana), cuyos colmillos por sí solos pueden llegar a pesar más de 45 kg, son notablesno solo por su tamaño sino también por su singular medio de comunicación. Los adultos pueden "hablar" entre ellos a distancias decientos de kilómetros, utilizando sonidos de baja frecuencia, análogos a las canciones de las ballenas, que están por debajo del límite...

• Tunisia - country.

  mixture of Berber and Arab stock, and they regard themselves as Arabs. Nearly everyone speaks Arabic. The population of Tunisia is concentrated in the coastal plain. It is fairly dense in the hilly north, but the arid plateau, basin, and south are thinly settled. About two-thirds of the country’s people live in urban areas. A Principal Cities The capital and largest city of Tunisia is the seaport of Tunis. Other important cities include Sfax, a port and center of trade on the eastern coast; Sūs...

• Pluvisilva - geografía.

  extiende por buena parte de Brasil y los países adyacentes, conocida con el nombre de Amazonia, es, con mucho, la pluvisilva más grande del mundo. Las selvas lluviosasmás grandes de Asia se encuentran en Indonesia (en concreto en las islas de Borneo y Sumatra), la península de Malaca y las Filipinas. La otra gran pluvisilva de Asia seextiende entre la isla de Nueva Guinea y en el norte de Australia. En África, la mayor parte de la pluvisilva se encuentra en torno a la costa atlántica y en la cue...

• Gorilla - biology.

  the DRC, Rwanda, and Uganda, along with a small population of gorillas on the Nigeria and Cameroon border, are most at risk. Each of these populations numbers onlyin the hundreds. Prominent gorilla conservation projects have been established in selected areas in an attempt to reverse the trend of declining population sizes. These programs havepioneered the development of ecotourism, in which tourists pay to visit areas with interesting natural and cultural features. Conservationists also work wi...

• Sir Henry Morton Stanley - biography.

• Etiopía - geografía.

  Los recursos de Etiopía son principalmente agrícolas. La meseta es fértil y todavía no está completamente desarrollada. La diversidad de suelos, clima y altitudes permite laobtención de una gran variedad de productos agrícolas. Hay también una gran variedad de depósitos minerales; los principales explotados comercialmente son hierro,cobre, cinc, plomo, potasio, oro y platino. 2.3 Flora y fauna PraderaLas praderas forman una zona ecológica entre los desiertos y los bosques templados e incluyen u...

• Kenya - country.

  threatens fish and other water life in the lake by depriving them of oxygen. Kenya is well known for its game parks—including Masai Mara Game Park and Tsavo National Park in the south, and Marsabit National Reserve in the north—whichattract large numbers of tourists and much revenue. Conservation of wildlife within reserves has thus received high priority. About 13 percent (2007) of Kenya’s totalland is protected. There are 229 (2004) threatened species in Kenya. Threatened habitats include the...

• Sudán (república) - geografía.

  bosques sudaneses. La deforestación, el sobrepastoreo y la pobre gestión del suelo han acelerado el proceso de desertización y el Sahara ahora penetra en suelopreviamente cultivable y boscoso. El país sufre periódicas y catastróficas inundaciones debido a desbordamientos fluviales. El Departamento de Estado estadounidense estima que hay más de 1 millón de minas antipersonas enterradas en Sudán, aunque el Gobierno sudanés cree que al menosdebe haber unos 3 millones de minas en el país. Algunas fu...

• Ottoman Empire - history.

  Süleyman ISüleyman I, the sultan of the Ottoman Empire during its zenith, became known in the western world as Süleyman the Magnificent. Hewas known among his own people as the Lawgiver because he revised the legal system of the empire. Süleyman had several sons,two of whom he executed after quarreling with them.Culver Pictures Bayazid died in captivity, a suicide according to some accounts, and a struggle for succession to the sultanate broke out among his sons. Muhammad I (reigned 1413-1421)ev...

• Tectónica de placas - ciencias de la naturaleza.

  continentales señalada por el famoso geólogo vienés Eduard Suess, hacia 1880. Reconoció un ‘tipo atlántico’ de margen, identificado por el truncado abrupto de antiguascadenas montañosas y por estructuras hendidas, y un ‘tipo pacífico’, marcado por montañas dispuestas en cordilleras paralelas, por líneas de volcanes y por terremotosfrecuentes. Para muchos geólogos, las costas de tipo pacífico parecen estar localizadas donde los geosinclinales se deforman y se elevan para formar montañas. 3 EXPANS...

• Diamante - ciencias de la naturaleza.

  Refracción de la luz en diamantesEl brillo de los diamantes se debe a su elevado índice de refracción, aproximadamente 2,4. El índice de refracción de un materialtransparente indica cuánto desvía los rayos de luz. La habilidad del joyero reside en tallar las facetas de modo que cada rayo de luzse refleje muchas veces antes de salir de la piedra. El índice de refracción es ligeramente distinto para cada color de la luz, por lo quela luz blanca se divide en sus componentes dando lugar a los fuegos...

• Eritrea - country.

  1993 decree set up a formal transitional government under EPLF control. This provided for a National Assembly, a president, and council of ministers. Isaias Afwerki,secretary general of the EPLF, was formally elected president by the National Assembly in June 1993. A new constitution was approved in 1997. Under this constitution, the National Assembly is the country’s legislature. Its members are popularly elected to five-yearterms. A president, elected by the National Assembly to a five-year te...

• Victoria (queen) I INTRODUCTION Victoria (queen) (1819-1901), queen of the United Kingdom of Great Britain and Ireland (1837-1901) and empress of India (1876-1901).

  Queen Victoria never truly recovered from Albert’s death in December 1861 at the age of 42. For almost a decade she remained in strict mourning. She rarely set footin London, and she avoided most public occasions, including the state opening of Parliament. She made an exception, however, for the unveiling of statues dedicated toPrince Albert and, after a few years, for attendance at army reviews. Behind the scenes, she continued to correspond with and talk to her ministers, and she took comfort...

• Victoria (queen).

  Queen Victoria never truly recovered from Albert’s death in December 1861 at the age of 42. For almost a decade she remained in strict mourning. She rarely set footin London, and she avoided most public occasions, including the state opening of Parliament. She made an exception, however, for the unveiling of statues dedicated toPrince Albert and, after a few years, for attendance at army reviews. Behind the scenes, she continued to correspond with and talk to her ministers, and she took comfort...

• Valley.

  Except in mountainous terrain, rivers are almost always flanked by floodplains. Floodplains are flat wide deposits of alluvium, river-deposited sediment, on either side of the river channel. During floods, a river overflows its banks and spreads out the sediment near the river to form a floodplain. Floodplains of large rivers, such as thoseof the Mississippi River, can be flat areas tens of kilometers across. River channels migrate back and forth across their floodplains as alluvium is repeate...

• Valley - Geography.

  Except in mountainous terrain, rivers are almost always flanked by floodplains. Floodplains are flat wide deposits of alluvium, river-deposited sediment, on either side of the river channel. During floods, a river overflows its banks and spreads out the sediment near the river to form a floodplain. Floodplains of large rivers, such as thoseof the Mississippi River, can be flat areas tens of kilometers across. River channels migrate back and forth across their floodplains as alluvium is repeate...