997 resultados para Africa, Northern


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Anaemia has a significant impact on child development and mortality and is a severe public health problem in most countries in sub-Saharan Africa. Nutritional and infectious causes of anaemia are geographically variable and anaemia maps based on information on the major aetiologies of anaemia are important for identifying communities most in need and the relative contribution of major causes. We investigated the consistency between ecological and individual-level approaches to anaemia mapping, by building spatial anaemia models for children aged ≤15 years using different modeling approaches. We aimed to a) quantify the role of malnutrition, malaria, Schistosoma haematobium and soil-transmitted helminths (STH) for anaemia endemicity in children aged ≤15 years and b) develop a high resolution predictive risk map of anaemia for the municipality of Dande in Northern Angola. We used parasitological survey data on children aged ≤15 years to build Bayesian geostatistical models of malaria (PfPR≤15), S. haematobium, Ascaris lumbricoides and Trichuris trichiura and predict small-scale spatial variation in these infections. The predictions and their associated uncertainty were used as inputs for a model of anemia prevalence to predict small-scale spatial variation of anaemia. Stunting, PfPR≤15, and S. haematobium infections were significantly associated with anaemia risk. An estimated 12.5%, 15.6%, and 9.8%, of anaemia cases could be averted by treating malnutrition, malaria, S. haematobium, respectively. Spatial clusters of high risk of anaemia (>86%) were identified. Using an individual-level approach to anaemia mapping at a small spatial scale, we found that anaemia in children aged ≤15 years is highly heterogeneous and that malnutrition and parasitic infections are important contributors to the spatial variation in anemia risk. The results presented in this study can help inform the integration of the current provincial malaria control program with ancillary micronutrient supplementation and control of neglected tropical diseases, such as urogenital schistosomiasis and STH infection.

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Anaemia is known to have an impact on child development and mortality and is a severe public health problem in most countries in sub-Saharan Africa. We investigated the consistency between ecological and individual-level approaches to anaemia mapping by building spatial anaemia models for children aged ≤15 years using different modelling approaches. We aimed to (i) quantify the role of malnutrition, malaria, Schistosoma haematobium and soil-transmitted helminths (STHs) in anaemia endemicity; and (ii) develop a high resolution predictive risk map of anaemia for the municipality of Dande in northern Angola. We used parasitological survey data for children aged ≤15 years to build Bayesian geostatistical models of malaria (PfPR≤15), S. haematobium, Ascaris lumbricoides and Trichuris trichiura and predict small-scale spatial variations in these infections. Malnutrition, PfPR≤15, and S. haematobium infections were significantly associated with anaemia risk. An estimated 12.5%, 15.6% and 9.8% of anaemia cases could be averted by treating malnutrition, malaria and S. haematobium, respectively. Spatial clusters of high risk of anaemia (>86%) were identified. Using an individual-level approach to anaemia mapping at a small spatial scale, we found that anaemia in children aged ≤15 years is highly heterogeneous and that malnutrition and parasitic infections are important contributors to the spatial variation in anaemia risk. The results presented in this study can help inform the integration of the current provincial malaria control programme with ancillary micronutrient supplementation and control of neglected tropical diseases such as urogenital schistosomiasis and STH infections.

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The ancestors of present-day man (Homo sapiens sapiens) appeared in East Africa some three and a half million years ago (Australopithecs), and then migrated to Europe, Asia, and later to the Americas, thus beginning the differentiation process. The passage from nomadic to sedentary life took place in the Middle East in around 8000 BC. Wars, spontaneous migrations and forced migrations (slave trade) led to enormous mixtures of populations in Europe and Africa and favoured the spread of numerous parasitic diseases with specific strains according to geographic area. The three human plasmodia (Plasmodium falciparum, P. vivax, and P. malariae) were imported from Africa into the Mediterranean region with the first human migrations, but it was the Neolithic revolution (sedentarisation, irrigation, population increase) which brought about actual foci for malaria. The reservoir for Leishmania infantum and L. donovani - the dog - has been domesticated for thousands of years. Wild rodents as reservoirs of L. major have also long been in contact with man and probably were imported from tropical Africa across the Sahara. L. tropica, by contrast, followed the migrations of man, its only reservoir. L. infantum and L. donovani spread with man and his dogs from West Africa. Likewise, for thousands of years, the dog has played an important role in the spread and the endemic character of hydatidosis through sheep (in Europe and North Africa) and dromadary (in the Sahara and North Africa). Schistosoma haematobium and S. mansoni have existed since prehistoric times in populations living in or passing through the Sahara. These populations then transported them to countries of Northern Africa where the specific, intermediary hosts were already present. Madagascar was inhabited by populations of Indonesian origin who imported lymphatic filariosis across the Indian Ocean (possibly of African origin since the Indonesian sailors had spent time on the African coast before reaching Madagascar). Migrants coming from Africa and Arabia brought with them the two African forms of bilharziosis: S. haematobium and S. mansoni.

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The history of the opening seaway from the westernmost Tethys to the Central Atlantic is traced by the analysis of the sedimentary facies development in the external Rif basin of Northern Morocco and the geological and seismic data from the Moroccan Atlantic continental margin. In the Rif basin, after the early Sinemurian, sedimentary facies dated by ammonites, foraminifers and brachiopods, indicate a progression of rapid subsidence resulting from extensional tectonic (tilted blocks, escarpment fault breccias, neptunian dykes etc.) from the N and NE to the S and SW. From the Toarcian to the Bajocian, deltas progress from the W and SW into the `'Rides sud-rifaines'' realm. From the late Bathonian to the Oxfordian, deep-sea fans develop in the external Rif. During the same period, deltaic sediments fill in the Middle Atlas basin of Eastern Morocco and progress into the external Rif. The top of the Jurassic is characterised by carbonate deposits. At the northwestern corner of Africa, the subsidence of the sedimentary basins by rifting is initiated in the late Triassic; however, at the Mazagan transect of the Atlantic continental margin, the tectonic pattern characteristic of a passive continental margin appears clearly only in the early Jurassic. At the foot of the Mazagan escarpment, the sedimentary record shows a foundering of the first bloc during early to middle Lias. A thermal uplift phase is indicated by emersion of the African margin shoulder in late Liassic, and thermal relaxation starts in the middle Jurassic. The morphology of this transect, compared with the conjugate side of the American continent is most easily explained by the uniform sense simple shear model.

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Climate change and variability in sub-Saharan West Africa is expected to have negative consequences for crop and livestock farming due to the strong dependence of these sectors on rainfall and natural resources, and the low adaptive capacity of crops farmers, agro-pastoralist and pastoralists in the region. The objective of this PhD research was to investigate the anticipated impacts of expected future climate change and variability on nutrition and grazing management of livestock in the prevailing extensive agro-pastoral and pastoral systems of the Sahelian and Sudanian zones of Burkina Faso. To achieve this, three studies were undertaken in selected village territories (100 km² each) in the southern Sahelian (Taffogo), northern Sudanian (Nobere, Safane) and southern Sudanian (Sokouraba) zone of the country during 2009 and 2010. The choice of two villages in the northern Sudanian zone was guided by the dichotomy between intense agricultural land use and high population density near Safane, and lower agricultural land use in the tampon zone between the village of Nobere and the National Park Kaboré Tambi of Pô. Using global positioning and geographical information systems tools, the spatio-temporal variation in the use of grazing areas by cattle, sheep and goats, and in their foraging behaviour in the four villages was assessed by monitoring three herds each per species during a one-year cycle (Chapter 2). Maximum itinerary lengths (km/d) were observed in the hot dry season (March-May); they were longer for sheep (18.8) and cattle (17.4) than for goats (10.5, p<0.05). Daily total grazing time spent on pasture ranged from 6 - 11 h with cattle staying longer on pasture than small ruminants (p<0.05). Feeding time accounted for 52% - 72% of daily time on pasture, irrespective of species. Herds spent longer time on pasture and walked farther distances in the southern Sahelian than the two Sudanian zones (p<0.01), while daily feeding time was longer in the southern Sudanian than in the other two zones (p>0.05). Proportional time spent resting decreased from the rainy (June - October) to the cool (November - February) and hot dry season (p<0.05), while in parallel the proportion of walking time increased. Feeding time of all species was to a significantly high proportion spent on wooded land (tree crown cover 5-10%, or shrub cover >10%) in the southern Sahelian zone, and on forest land (tree crown cover >10%) in the two Sudanian zones, irrespective of season. It is concluded that with the expansion of cropland in the whole region, remaining islands of wooded land, including also fields fallowed for three or more years with their considerable shrub cover, are particularly valuable pasturing areas for ruminant stock. Measures must be taken that counteract the shrinking of wooded land and forests across the whole region, including also active protection and (re)establishment of drought-tolerant fodder trees. Observation of the selection behaviour of the above herds of cattle and small ruminant as far as browse species were concerned, and interviews with 75 of Fulani livestock keepers on use of browse as feed by their ruminant stock and as remedies for animal disease treatment was undertaken (Chapter 3) in order to evaluate the consequence of climate change for the contribution of browse to livestock nutrition and animal health in the extensive grazing-based livestock systems. The results indicated that grazing cattle and small ruminants do make considerable use of browse species on pasture across the studied agro-ecological zones. Goats spent more time (p<0.01) feeding on browse species than sheep and cattle, which spent a low to moderate proportion of their feeding time on browsing in any of the study sites. As far as the agro-ecological zones were concerned, the contribution of browse species to livestock nutrition was more important in the southern Sahelian and northern Sudanian zone than the southern Sudanian zone, and this contribution is higher during the cold and hot dry season than during the rainy season. A total of 75 browse species were selected on pasture year around, whereby cattle strongly preferred Afzelia africana, Pterocarpus erinaceus and Piliostigma sp., while sheep and goats primarily fed on Balanites aegyptiaca, Ziziphus mauritiana and Acacia sp. Crude protein concentration (in DM) of pods or fruits of the most important browse species selected by goats, sheep and cattle ranged from 7% to 13% for pods, and from 10% to 18% for foliage. The concentration of digestible organic matter of preferred browse species mostly ranged from 40% to 60%, and the concentrations of total phenols, condensed tannins and acid detergent lignin were low. Linear regression analyses showed that browse preference on pasture is strongly related to its contents (% of DM) of CP, ADF, NDF and OM digestibility. Interviewed livestock keepers reported that browse species are increasingly use by their grazing animals, while for animal health care use of tree- and shrub-based remedies decreased over the last two decades. It is concluded that due to climate change with expected negative impact on the productivity of the herbaceous layer of communal pastures browse fodder will gain in importance for animal nutrition. Therefore re-establishment and dissemination of locally adapted browse species preferred by ruminants is needed to increase the nutritional situation of ruminant stock in the region and contribute to species diversity and soil fertility restoration in degraded pasture areas. In Chapter 4 a combination of household surveys and participatory research approaches was used in the four villages, and additionally in the village of Zogoré (southern Sahelian zone) and of Karangasso Vigué (northern Sudanian zone) to investigate pastoralists’ (n= 76) and agro-pastoralists’ (n= 83) perception of climate change, and their adaptation strategies in crop and livestock production at farm level. Across the three agro-ecological zones, the majority of the interviewees perceived an increase in maximum day temperatures and decrease of total annual rainfall over the last two decades. Perceptions of change in climate patterns were in line with meteorological data for increased temperatures while for total rainfall farmers’ views contrasted the rainfall records which showed a slight increase of precipitation. According to all interviewees climate change and variability have negative impacts on their crop and animal husbandry, and most of them already adopted some coping and adaptation strategies at farm level to secure their livelihoods and reduce negative impacts on their farming system. Although these strategies are valuable and can help crop and livestock farmers to cope with the recurrent droughts and climate variability, they are not effective against expected extreme climate events. Governmental and non-governmental organisations should develop effective policies and strategies at local, regional and national level to support farmers in their endeavours to cope with climate change phenomena; measures should be site-specific and take into account farmers’ experiences and strategies already in place.

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The issue of child labour in the artisanal and small-scale mining (ASM) economy is attracting significant attention worldwide. This article critically examines this ‘problem’ in the context of sub-Saharan Africa, where a lack of formal sector employment opportunities and/or the need to provide financial support to their impoverished families has led tens of thousands of children to take up work in this industry. The article begins by engaging with the main debates on child labour in an attempt to explain why young boys and girls elect to pursue arduous work in ASM camps across the region. The remainder of the article uses the Ghana experience to further articulate the challenges associated with eradicating child labour at ASM camps, drawing upon recent fieldwork undertaken in Talensi-Nabdam District, Upper East Region. Overall, the issue of child labour in African ASM communities has been diagnosed far too superficially, and until donor agencies and host governments fully come to grips with the underlying causes of the poverty responsible for its existence, it will continue to burgeon.

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This paper critically reflects on why, in many rural stretches of sub-Saharan Africa, scores of people engage in artisanal and small-scale mining (ASM) activity – low-tech, labour intensive mineral extraction – for lengthy periods of time. It argues that a large share of the region’s ASM operators have mounting debts which prevent them from pursuing alternative, less arduous, employment. The paper concludes with an analysis of findings from research carried out by the author in Talensi-Nabdam District, Northern Ghana, which captures the essence of the poverty trap now plaguing so many ASM communities in sub-Saharan Africa.

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Two different TAMSAT (Tropical Applications of Meteorological Satellites) methods of rainfall estimation were developed for northern and southern Africa, based on Meteosat images. These two methods were used to make rainfall estimates for the southern rainy season from October 1995 to April 1996. Estimates produced by both TAMSAT methods and estimates produced by the CPC (Climate Prediction Center) method were then compared with kriged data from over 800 raingauges in southern Africa. This shows that operational TAMSAT estimates are better over plateau regions, with 59% of estimates within one standard error (s.e.) of the kriged rainfall. Over mountainous regions the CPC approach is generally better, although all methods underestimate and give only 40% of estimates within 1 s.e. The two TAMSAT methods show little difference across a whole season, but when looked at in detail the northern method gives unsatisfactory calibrations. The CPC method does have significant overall improvements by building in real-time raingauge data, but only where sufficient raingauges are available.

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New compilations of African pollen and lake data are compared with climate (CCM1, NCAR, Boulder) and vegetation (BIOME 1.2, GSG, Lund) simulations for the last glacial maximum (LGM) and early to mid-Holocene (EMH). The simulated LGM climate was ca 4°C colder and drier than present, with maximum reduction in precipitation in semi-arid regions. Biome simulations show lowering of montane vegetation belts and expansion of southern xerophytic associations, but no change in the distribution of deserts and tropical rain forests. The lakes show LGM conditions similar or drier than present throughout northern and tropical Africa. Pollen data indicate lowering of montane vegetation belts, the stability of the Sahara, and a reduction of rain forest. The paleoenvironmental data are consistent with the simulated changes in temperature and moisture budgets, although they suggest the climate model underestimates equatorial aridity. EMH simulations show temperatures slightly less than present and increased monsoonal precipitation in the eastern Sahara and East Africa. Biome simulations show an upward shift of montane vegetation belts, fragmentation of xerophytic vegetation in southern Africa, and a major northward shift of the southern margin of the eastern Sahara. The lakes indicate conditions wetter than present across northern Africa. Pollen data show an upward shift of the montane forests, the northward shift of the southern margin of the Sahara, and a major extension of tropical rain forest. The lake and pollen data confirm monsoon expansion in eastern Africa, but the climate model fails to simulate the wet conditions in western Africa.

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Information on the breeding biology of the White-headed Vulture Trigonoceps occipitalis is limited and published data are few. Within the Kruger National Park in north-east South Africa there is a regionally important population of about 60 White-headed Vulture pairs, of which 22 pairs were monitored for five years between 2008 and 2012 to determine key aspects of their breeding biology. Across 73 pair/years the mean productivity of 55 breeding attempts was 0.69 chicks per pair. Median egg-laying date across all of the Kruger National Park was 27 June, but northern nests were approximately 30 d later than southern nests. Mean (SD) nearest-neighbour distance was 9 976  7 965 m and inter-nest distances ranged from 1 400 m to more than 20 km, but this did not differ significantly between habitat types. Breeding productivity did not differ significantly between habitat types. The results presented here are the first for this species in Kruger National Park and provide details against which future comparisons can be made.

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Excavations at Haua Fteah cave in Cyrenaica, Libya, have revealed a cultural sequence that may span the last glacial–interglacial-glacial cycle. The TRANS-NAP project has been re-excavating Haua Fteah and conducting geoarchaeological survey of an ecologically diverse landscape that includes the fertile Gebel Akhdar and littoral, pre-desert, and desert biomes. A major aim of this project is to characterize cultural and environmental changes across the region and correlate the surface archaeology with that from Haua Fteah. To date, 181 sites have been recorded, ranging from the Middle Stone Age (MSA) to Late Stone Age (LSA). Their geographic distribution suggests temporal variation in patterns of hominin habitat preference, with significantly more LSA than MSA sites at higher elevations. The surface archaeology also points to substantial spatiotemporal technological variation within the MSA. These patterns may be explained by both paleoenvironmental change and paleodemographic shifts in the region, resulting in a variety of hominin adaptive responses.

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Establishing effective networks of protected areas (PAS) is one of the major goals of conservation strategies worldwide. However, the success of PAS in promoting biodiversity conservation depends on their integration to local and regional contexts, reducing and mitigating human impacts originating from buffer zones. Community perceptions affect interactions between residents and PAS, and thereby conservation effectiveness. Research at Tocantins state (northern Brazilian Cerrado), aimed to analyse local community perceptions of four PAs, discussing how different factors may influence these. Perceptions were assessed through standardized interviews applied to PA employees and 275 local inhabitants. There was modest community participation in PA establishment and management. Residents were aware of the PAS` existence, but were unfamiliar with their goals. Length of residency and occupation of inhabitants influenced their PA perceptions, shaping different people-park relations in each of the four studied PAs. Involvement of local residents in PA planning and management represents a central strategy to strengthen local support for PAS over the long term. In those areas that still have settlements inside their boundaries, community relocation should follow a careful participatory process to avoid significant changes in local perceptions and attitudes towards these PAS, crucial for conserving Brazilian biodiversity.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Com o objetivo de investigar a origem da mutação bS na população da região norte do Brasil, foram analisados polimorfismos de DNA no complexo de genes b da hemoglobina em 30 pacientes com anemia falciforme na população de Belém, a capital do Estado do Pará. Sessenta e sete por cento dos cromossomos bS analisados apresentaram o haplótipo Bantu, 30% o haplótipo Benin e 3% o haplótipo Senegal. A origem da mutação bS na população de Belém, estimada de acordo com a distribuição de haplótipos, não está de acordo com a esperada com base em dados históricos sobre o tráfico de escravos para a região norte, os quais indicam uma reduzida contribuição de escravos da região do Benin. Essas diferenças podem ser atribuídas ao tráfico interno de escravos, bem como ao posterior fluxo de populações imigrantes, particularmente de nordestinos. A distribuição de haplótipos em Belém não difere significativamente da observada em outras regiões brasileiras, muito embora os dados históricos sugiram que a maioria dos escravos procedentes da região do Atlântico-Oeste africano, onde predomina o haplótipo Senegal, foi trazida para o norte do Brasil, enquanto que o nordeste (Bahia, Pernambuco e Maranhão) recebeu o maior contingente de escravos oriundos da região centro-oeste africana, onde o haplótipo Benin é o mais comum. Nós sugerimos que as diferenças regionais quanto à procedência dos escravos africanos também foram modificadas pelo tráfico de escravos estabelecido entre as diferentes regiões brasileiras e posteriormente pelos movimentos migratórios.

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1. Blue whale locations in the Southern Hemisphere and northern Indian Ocean were obtained from catches (303 239), sightings (4383 records of ≥ 8058 whales), strandings (103), Discovery marks (2191) and recoveries (95), and acoustic recordings. 2. Sighting surveys included 7 480 450 km of effort plus 14 676 days with unmeasured effort. Groups usually consisted of solitary whales (65.2%) or pairs (24.6%); larger feeding aggregations of unassociated individuals were only rarely observed. Sighting rates (groups per 1000 km from many platform types) varied by four orders of magnitude and were lowest in the waters of Brazil, South Africa, the eastern tropical Pacific, Antarctica and South Georgia; higher in the Subantarctic and Peru; and highest around Indonesia, Sri Lanka, Chile, southern Australia and south of Madagascar. 3. Blue whales avoid the oligotrophic central gyres of the Indian, Pacific and Atlantic Oceans, but are more common where phytoplankton densities are high, and where there are dynamic oceanographic processes like upwelling and frontal meandering. 4. Compared with historical catches, the Antarctic (‘true’) subspecies is exceedingly rare and usually concentrated closer to the summer pack ice. In summer they are found throughout the Antarctic; in winter they migrate to southern Africa (although recent sightings there are rare) and to other northerly locations (based on acoustics), although some overwinter in the Antarctic. 5. Pygmy blue whales are found around the Indian Ocean and from southern Australia to New Zealand. At least four groupings are evident: northern Indian Ocean, from Madagascar to the Subantarctic, Indonesia to western and southern Australia, and from New Zealand northwards to the equator. Sighting rates are typically much higher than for Antarctic blue whales.