981 resultados para West-african populations


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We compared the responses of native and non-native populations of the seaweed Gracilaria vermiculophylla to heat shock in common garden-type experiments. Specimens from six native populations in East Asia and from eight non-native populations in Europe and on the Mexican Pacific coast were acclimated to two sets of identical conditions before their resistance to heat shock was examined. The experiments were carried out twice - one time in the native range in Qingdao, China and one time in the invaded range in Kiel, Germany - to rule out effects of specific local conditions. In both testing sites the non-native populations survived heat shock significantly better than the native populations, The data underlying this statement are presented in https://doi.pangaea.de/10.1594/PANGAEA.859335. After three hours of heat shock G. vermiculophylla exhibited increased levels of heat shock protein 70 (HSP70) and of a specific isoform of haloperoxidase, suggesting that both enzymes could be required for heat shock stress management. However, the elevated resistance toward heat shock of non-native populations only correlated with an increased constitutive expression of heat shock protein 70 (HSP70). The haloperoxidase isoform was more prominent in native populations, suggesting that not only increased HSP70 expression, but also reduced allocation into haloperoxidase expression after heat shock was selected during the invasion history. The data describing expression of HSP70 and three different isoforms of haloperoxidase are presented in https://doi.pangaea.de/10.1594/PANGAEA.859358.

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We have analyzed DNA sequences from world-wide geographic strains of Plasmodium falciparum and found a complete absence of synonymous DNA polymorphism at 10 gene loci. We hypothesize that all extant world populations of the parasite have recently derived (within several thousand years) from a single ancestral strain. The upper limit of the 95% confidence interval for the time when this most recent common ancestor lived is between 24,500 and 57,500 years ago (depending on different estimates of the nucleotide substitution rate); the actual time is likely to be much more recent. The recent origin of the P. falciparum populations could have resulted from either a demographic sweep (P. falciparum has only recently spread throughout the world from a small geographically confined population) or a selective sweep (one strain favored by natural selection has recently replaced all others). The selective sweep hypothesis requires that populations of P. falciparum be effectively clonal, despite the obligate sexual stage of the parasite life cycle. A demographic sweep that started several thousand years ago is consistent with worldwide climatic changes ensuing the last glaciation, increased anthropophilia of the mosquito vectors, and the spread of agriculture. P. falciparum may have rapidly spread from its African tropical origins to the tropical and subtropical regions of the world only within the last 6,000 years. The recent origin of the world-wide P. falciparum populations may account for its virulence, as the most malignant of human malarial parasites.

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This layer is a georeferenced raster image of the historic paper map entitled: Carte de la Barbarie, le [sic] la Nigritie et del la Guinée, par Guillaume de l'Isle de l'Academie Royale des Sciences. It was published by ex officina Nicolai Visscher, ca. 1710. Scale [ca.1:9,000,000]. Covers West and North Africa. Map in French.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Africa Sinusoidal projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, routes and roads, territorial boundaries, shoreline features, and more. Relief shown pictorially. Includes notes.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

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This layer is a georeferenced raster image of the historic paper map entitled: Carte de la Barbarie, le la Nigritie et de la Guinée, par Guill[au]me Del'Isle, de l'Academie Royale des Sciences. It was published by Chez Jean Cóvens et Corneille Mortier, Geographes ca. 1730. Scale [ca.1:9,250,000]. Covers West and North Africa. Map in French.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Africa Sinusoidal projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, roads and routes, territorial boundaries, shoreline features, and more. Relief shown pictorially. Includes notes.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

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This layer is a georeferenced raster image of the historic paper map entitled: L'Afrique, ou Lybie ulterieure : ou sont le Saara, ou desert, le pays des Negres, la Guinee, et les pays circonv. tirée en partie de Sanut, et de l'Arabe de Nubie, en partie de diverses cartes veües jusques a present par le S. Sanson d'Abbeville, geog. ordre. du Roy ; I. Somer Pruthenus, sculp. It was published by Chez Pierre Mariette, rue St. Iacques a l'Esperance in 1655. Scale [ca. 1:10,500,000]. Covers portions of North and West Africa. Map in French.The image inside the map neatline is georeferenced to the surface of the earth and fit to the World Miller Cylindrical projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, territorial boundaries, shoreline features, and more. Relief shown pictorially.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

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This layer is a georeferenced raster image of the historic paper map entitled: Guinea propria : nec non Nigritiae vel terrae Nigrorum maxima pars : Geographis hodiernis dicta utraque Aethiopia Inferior, & huius quidem pars australis ex delineationibus Anvillianis itineri Guineensi D. de Marchais insertis secundum Leges proiectionis stereographicae Hasianae, designata & edita studio & labore Homannianorum Heredum A. 1743 = Guinée de meme que la plus grande parties du pais des Negres : appellées par les geographes modernes Ethiopie inferieure et meridionale, tirées des morceaux geographiques de Mr. d'Anville, qu'il a inseres au voyage du Chev. de Marchais, & puis dessinées suivant les loix de la nouvelle projection de feu Mr. le prof. Has, par les Heritiers d'Homan. A 1743. It was published by edita studio & labore Homannianorum Heredum ca. 1752. Scale [ca. 1:7,400,000]. Covers portions of West and Central Africa. Map in Latin.The image inside the map neatline is georeferenced to the surface of the earth and fit to the World Miller Cylindrical projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, territorial boundaries, shoreline features, and more. Relief shown pictorially. Includes also notes.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

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This layer is a georeferenced raster image of the historic paper map entitled: Nova Barbariae descriptio. It was published by Apud Ioannem Ianssonium in 1647. Scale [ca. 1:12,100,000]. Cover North & West Africa. Map in Latin.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Africa Lambert Conformal Conic projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, territorial boundaries, shoreline features, and more. Relief shown pictorially. Includes also notes.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

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Trade is a key element of the development policy of the European Union (EU). As the most important trading partner of developing countries, the EU attempts to facilitate the participation of developing countries in global trade and contribute to economic growth through providing market access and financial assistance. For twenty-five years, the commitment of the EU was largely focused on its former colonies, more specifically in Africa, the Caribbean and the Pacific (ACP). The developing world, in terms of the EU’s trade policy, was therefore divided between ACP states with special provisions under the Lomé Conventions and all other developing countries. With the new millennium, this special relationship came to an end. Pressure from several member states1 and the World Trade Organization (WTO) led to an overhaul of the EU’s trade regime vis-à-vis developing countries and to the loss of the privileged position of ACP countries. The result of this overhaul is still pending. Economic Partnership Agreements (EPAs) – to be negotiated between the EU and several ACP regions – have only been realized in the Caribbean. This article will to examine the negotiations between the EU and West Africa and discuss the interests involved on the African side. Following the introduction, the second part of this article is dedicated to the Lomé Conventions with a focus on the change occurring from the third to the fourth revision in order to understand the current situation. The third part is going to take a look at the Cotonou agreement and the trade regime of the EU in general before turning to the negotiations for an Economic Partnership Agreement between the EU and West Africa. The conclusion summarizes the main findings.