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  1. West Africa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    With its vast expanses of sand, framed by mountain ranges and exposed rock, northwestern Africa makes a pretty picture when viewed from above. This image was acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. The Canary Islands can be seen on the left side of the image just off Africa's Atlantic shore. The light brown expanse running through the northern two thirds of the image is the Sahara Desert. The desert runs up against the dark brown Haut Atlas mountain range of Morocco in the northwest, the Atlantic Ocean to the west and the semi-arid (light brown pixels) Sahelian region in the South. The Sahara, however, isn't staying put. Since the 1960s, the desert has been expanding into the Sahelian region at a rate of up to 6 kilometers per year. In the 1980s this desert expansion, combined with over cultivation of the Sahel, caused a major famine across west Africa. Over the summer months, strong winds pick up sands from the Sahara and blow them across the Atlantic as far west as North America, causing air pollution in Miami and damaging coral reefs in the Bahamas and the Florida Keys. The white outlines on the map represent country borders. Starting at the top-most portion of the map and working clockwise, the countries shown are Morocco, Western Sahara, Mauritania, Senegal, Mali, Burkina Fasso, Nigeria, Mali (again), and Algeria. Image by Reto Stockli, Robert Simmon, and Brian Montgomery, NASA Earth Observatory, based on data from MODIS

  2. West and Central Africa.

    PubMed

    Lydie, N; Robinson, N J

    1998-01-01

    This article reviews scientific and other literature during the 1990s that links migration and mobility with the spread of sexually transmitted diseases (STDs), including HIV/AIDS. The focus is on key population groups linked to the spread of HIV and STDs in West and Central Africa: migrant laborers, truck drivers, itinerant traders, commercial sex workers (CSWs), and refugees. Countries with high emigration and immigration tend to have high levels of HIV infection, with the exception of Senegal. The main destination of immigrants are Senegal, Nigeria, and Cote d'Ivoire in West Africa and Cameroon, Congo, Gabon, and Congo in Central Africa. The risk of infection and the spread of HIV is variable among migrants. There is little in the literature that substantiates hypotheses about the strong association between migration and HIV-positive status. Information is needed on the duration, frequency of return visits, living conditions, sexual activities with multiple partners, and information before departure, along the routes, at final destination, and at the time of returns. Action-based research in five West African countries (Burkina Faso, Cote d'Ivoire, Mali, Niger, and Senegal) should produce results in late 1998. Comparable studies in Central Africa are unknown. Regional studies should be complemented by local studies. Prevention would benefit from studies on the relative size of these five population groups by geographic location.

  3. Drought in West Africa

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Drought settled over West Africa's Ivory Coast region when wet season rains came late in 2007. Instead of beginning in February, the rainy season didn't start until March, and steady rains didn't start until late March, said the Famine Early Warning System Network. Though the rain had started to alleviate the drought, vegetation was still depressed in parts of Cote d'Ivoire (Ivory Coast) between March 22 and April 6, 2007, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured the data used to make this image. The image shows current vegetation conditions compared to average conditions recorded since 2000. Areas where plants are growing more slowly or more sparsely than average are brown, while areas where vegetation is denser than average are green. The brown tint that dominates the image indicates that plants through most of the country are more sparse than normal. Among the crops affected by the lack of rain was West Africa's cocoa crop. About 70 percent of the world's cocoa comes from West Africa, and Cote d'Ivoire is a top grower, said Reuters. Cocoa prices climbed as the crop fell short. Farmers called the drought the worst in living memory, Reuters said. The delay in rainfall also led to water shortages in parts of Cote d'Ivoire, according to the United Nations Office for the Coordination of Humanitarian Affairs.

  4. Ebola in West Africa

    PubMed Central

    Raka, Lul; Guardo, Monica

    2015-01-01

    Ebola viral disease (EVD) is a severe and life-threatening disease. The current Ebola outbreak in West Africa entered its second year and is unprecedented because it is the largest one in history, involved urban centers and affected a large number of health care workers. It quickly escalated from medical into a humanitarian, social, economic, and security crisis. The primary pillars to prevent EVD are: early diagnosis, isolation of patients, contact tracing and monitoring, safe burials, infection prevention and control and social mobilization. The implementation of all these components was challenged in the field. Key lessons from this Ebola outbreak are that countries with weak health care systems can’t withstand the major outbreaks; preparedness to treat the first confirmed cases is a national emergency; all control measures must be coordinated together and community engagement is the great factor to combat this disease. PMID:27275217

  5. Ebola in West Africa.

    PubMed

    Raka, Lul; Guardo, Monica

    2015-03-15

    Ebola viral disease (EVD) is a severe and life-threatening disease. The current Ebola outbreak in West Africa entered its second year and is unprecedented because it is the largest one in history, involved urban centers and affected a large number of health care workers. It quickly escalated from medical into a humanitarian, social, economic, and security crisis. The primary pillars to prevent EVD are: early diagnosis, isolation of patients, contact tracing and monitoring, safe burials, infection prevention and control and social mobilization. The implementation of all these components was challenged in the field. Key lessons from this Ebola outbreak are that countries with weak health care systems can't withstand the major outbreaks; preparedness to treat the first confirmed cases is a national emergency; all control measures must be coordinated together and community engagement is the great factor to combat this disease.

  6. Africa.

    ERIC Educational Resources Information Center

    Martz, Carlton

    2001-01-01

    This publication explores issues related to Africa. It examines the U.S. response to the Barbary pirate states (Morocco, Algiers, Tunis, Tripoli) in the early 19th century; the current AIDS crisis in Africa; and 14th century Mali and other Islamic lands through the eyes of Ibn Battuta, who traveled throughout the Muslim world. Each article…

  7. Africa.

    ERIC Educational Resources Information Center

    Happel, Sue; Loeb, Joyce

    Although the activities in this unit are designed primarily for students in the intermediate grades, the document's text, illustrations, and bibliographic references are suitable for anyone interested in learning about Africa. Following a brief introduction and map work, the document is arranged into six sections. Section 1 traces Africa's history…

  8. Emigration dynamics in West Africa.

    PubMed

    Makinwa-adebusoye, P K

    1995-01-01

    This report on the emigration dynamics at work in Western Africa opens by noting that this region comprises an important migration system with large legal and illegal movements of people within the region and to industrialized countries. Migration has been fueled by high growth rates coupled with lower growth rates of per capital income. Migration takes the form of continuing inflow into receiving countries, such as the Ivory Coast, sudden changes in migration status (in Ghana and Nigeria) reflecting sudden economic changes, a brain drain to developed countries, and an influx of refugees. The second section of the report presents a brief look at historical migratory patterns, including those of nomads which continue today. Data limitations are addressed in section 3, and the drawbacks of census data for migration information are noted. The next section describes the economic and demographic factors in the region which contribute to migration. These include the long lasting effects of colonization in general, the exploitation of minerals, patterns of agricultural development, poverty, and population growth. A closer examination of these forces at work is provided in case studies of Ghana, Nigeria, and the migration stream from Burkina Faso to the Ivory Coast. Section 5 looks at the economic causes and effects of the brain drain. Social and cultural factors are covered in section 6, with an emphasis placed on family and migration networks. Section 7 covers political factors influencing migration, such as the efforts of people to retain contact with other members of their ethnic group who may live on the opposite side of an arbitrarily drawn (by colonizers) international border, the designation of administrative capital cities, and the ease in crossing borders without documentation. The next section describes the 1975 formation of the Economic Community for West Africa (ECOWAS) and its protocols regarding free movement of citizens within the states which comprise the

  9. Peacekeeping Operations in West Africa

    DTIC Science & Technology

    2000-04-01

    Africa 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR (S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7...are those of the author and do not reflect the official policy or position of the US government or the Department of Defense. In accordance with Air...1 DEFINITON OF — PEACEKEEPING OPERATIONS

  10. Combating Narco-Terrorism in West Africa

    DTIC Science & Technology

    2012-06-15

    stability of nation. ’>uhvcning government institmion:-. through corruption and harmjng citizen ~ worldwide. Tran~national criminal organizarions...permissive environment for drug cartels and terrorists to operate and find haven. West Africa’s strategic location, lack of governance , high...lack effective government institutions coupled with corruption. Poverty and lack of opportunities for West African youth have enabled drug traffickers

  11. Mastomys natalensis and Lassa fever, West Africa.

    PubMed

    Lecompte, Emilie; Fichet-Calvet, Elisabeth; Daffis, Stéphane; Koulémou, Kékoura; Sylla, Oumar; Kourouma, Fodé; Doré, Amadou; Soropogui, Barré; Aniskin, Vladimir; Allali, Bernard; Kouassi Kan, Stéphane; Lalis, Aude; Koivogui, Lamine; Günther, Stephan; Denys, Christiane; ter Meulen, Jan

    2006-12-01

    PCR screening of 1,482 murid rodents from 13 genera caught in 18 different localities of Guinea, West Africa, showed Lassa virus infection only in molecularly typed Mastomys natalensis. Distribution of this rodent and relative abundance compared with M. erythroleucus correlates geographically with Lassa virus seroprevalence in humans.

  12. Epidemiology: Malaria in a warmer West Africa

    NASA Astrophysics Data System (ADS)

    Caminade, C.; Jones, A. E.

    2016-11-01

    Malaria risk in West Africa is expected to fall (western region) or remain the same (eastern region) in response to climate change over the twenty-first century. This is primarily due to extreme temperature conditions projected under a high greenhouse gas emissions scenario.

  13. Lassa fever: another threat from West Africa.

    PubMed

    Brosh-Nissimov, Tal

    2016-01-01

    Lassa fever, a zoonotic viral infection, is endemic in West Africa. The disease causes annual wide spread morbidity and mortality in Africa, and can be imported by travelers. Possible importation of Lassa fever and the potential for the use of Lassa virus as an agent of bioterrorism mandate clinicians in Israel and other countries to be vigilant and familiar with the basic characteristics of this disease. The article reviews the basis of this infection and the clinical management of patients with Lassa fever. Special emphasis is given to antiviral treatment and infection control.

  14. West Africa land use and land cover time series

    USGS Publications Warehouse

    Cotillon, Suzanne E.

    2017-02-16

    Started in 1999, the West Africa Land Use Dynamics project represents an effort to map land use and land cover, characterize the trends in time and space, and understand their effects on the environment across West Africa. The outcome of the West Africa Land Use Dynamics project is the production of a three-time period (1975, 2000, and 2013) land use and land cover dataset for the Sub-Saharan region of West Africa, including the Cabo Verde archipelago. The West Africa Land Use Land Cover Time Series dataset offers a unique basis for characterizing and analyzing land changes across the region, systematically and at an unprecedented level of detail.

  15. Problem of hepatocellular carcinoma in West Africa

    PubMed Central

    Ladep, Nimzing G; Lesi, Olufunmilayo A; Mark, Pantong; Lemoine, Maud; Onyekwere, Charles; Afihene, Mary; Crossey, Mary ME; Taylor-Robinson, Simon D

    2014-01-01

    The incidence of hepatocellular carcinoma (HCC) is known to be high in West Africa with an approximate yearly mortality rate of 200000. Several factors are responsible for this. Early acquisition of risk factors; with vertical or horizontal transmission of hepatitis B (HBV), environmental food contaminants (aflatoxins), poor management of predisposing risk factors and poorly-managed strategies for health delivery. There has been a low uptake of childhood immunisation for hepatitis B in many West African countries. Owing to late presentations, most sufferers of HCC die within weeks of their diagnosis. Highlighted reasons for the specific disease pattern of HCC in West Africa include: (1) high rate of risk factors; (2) failure to identify at risk populations; (3) lack of effective treatment; and (4) scarce resources for timely diagnosis. This is contrasted to the developed world, which generally has sufficient resources to detect cases early for curative treatment. Provision of palliative care for HCC patients is limited by availability and affordability of potent analgesics. Regional efforts, as well as collaborative networking activities hold promise that could change the epidemiology of HCC in West Africa. PMID:25429316

  16. Simulation of Rainfall Variability Over West Africa

    NASA Astrophysics Data System (ADS)

    Bader, J.; Latif, M.

    The impact of sea surface temperature (SST) and vegetation on precipitation over West Africa is investigated with the atmospheric general circulation model ECHAM4.x/T42. Ensemble experiments -driven with observed SST- show that At- lantic SST has a significant influence on JJA precipitation over West Africa. Four- teen experiments were performed in which the climatological SST was enhanced or decreased by one Kelvin in certain ocean areas. Changing SST in the eastern tropi- cal Atlantic only caused significant changes along the Guinea Coast, with a positive SSTA increasing rainfall and a negative reducing it. The response was nearly linear. Changing SST in other ocean areas caused significant changes over West Africa, es- pecially in the Sahel area. The response is found to be non linear, with only negative SSTA leading to significant reduction in Sahel rainfall. Also, the impact of the SSTAs from the different ocean regions was not additive with respect to the rainfall. Four simulations with a coupled model (the simple dynamic vegetation model (SVege) and the ECHAM4-AGCM were coupled) were also performed, driven with observed SST from 1945 to 1998. The standard ECHAM-AGCM -forced by the same observed SST- was able to reproduce the drying trend from the fifties to the mid-eighties in the Sahel, but failed to mirror the magnitude of the rainfall anomalies. The coupled model was not only able to reproduce this drying trend, but was also able to better reproduce the amplitudes of the rainfall anomalies. The dynamic vegetation acted like an amplifier, increasing the SST induced rainfall anomalies.

  17. Niobium content of soils from West Africa

    USGS Publications Warehouse

    Grimaldi, F.S.; Berger, I.A.

    1961-01-01

    Analysis of twenty lateritic soil samples from West Africa has shown them to contain an average 24 p.p.m. of niobium; four similar samples taken from within a few miles from a niobium deposit contain from 79 to 87 p.p.m. niobium. It has been shown that as the aluminum content of the soils increases, the following depletion sequence is obtained: Si > Nb > Al = Fe The data indicate that, in general, high enrichments of niobium are not to be expected in lateritic soils. ?? 1961.

  18. West Africa’s War on Terrorism: Time and Patience

    DTIC Science & Technology

    2009-03-25

    National Defense University, November 15-16, 2005, Fort Lesley J. McNair, Washington, DC, 5. 59 Kevin A. O ’ Brien and Theodore Karasik, “Case Study...II, Empirical Findings,” 249. 63 Ibid. 64 Ibid. 65 O ’ Brien , “Case Study: West Africa.” 66 Akosah-Sarpong, Kofi, “Commentary: West Africa’s Military...67 O ’ Brien , “Case Study: West Africa,” 249. 68 McGowan, “Coups and Conflict in West Africa, 1955-2004: Part II, Empirical Findings,” 248. 69 Reuven

  19. Strategies for containing Ebola in West Africa.

    PubMed

    Pandey, Abhishek; Atkins, Katherine E; Medlock, Jan; Wenzel, Natasha; Townsend, Jeffrey P; Childs, James E; Nyenswah, Tolbert G; Ndeffo-Mbah, Martial L; Galvani, Alison P

    2014-11-21

    The ongoing Ebola outbreak poses an alarming risk to the countries of West Africa and beyond. To assess the effectiveness of containment strategies, we developed a stochastic model of Ebola transmission between and within the general community, hospitals, and funerals, calibrated to incidence data from Liberia. We find that a combined approach of case isolation, contact-tracing with quarantine, and sanitary funeral practices must be implemented with utmost urgency in order to reverse the growth of the outbreak. As of 19 September, under status quo, our model predicts that the epidemic will continue to spread, generating a predicted 224 (134 to 358) daily cases by 1 December, 280 (184 to 441) by 15 December, and 348 (249 to 545) by 30 December.

  20. Marriage in West Africa--A Composite. Mini-Module.

    ERIC Educational Resources Information Center

    African-American Inst., New York, NY. School Services Div.

    This module contains a description of the responsibilities and ceremony of marriage in west Africa, seven discussion questions exploring the differences between Western and African marriage customs, five enrichment activities, and a bibliography of five books about love and marriage in Africa. The general discussion relates the engagement of a…

  1. Case report: melioidosis imported from West Africa to Europe.

    PubMed

    Cuadros, Juan; Gil, Horacio; Miguel, Julio De; Marabé, Graciela; Gómez-Herruz, Teresa Arroyo Peña; Lobo, Bruno; Marcos, Ruth; Anda, Pedro

    2011-08-01

    We report the first case of imported melioidosis in Spain from a diabetic immigrant who visited West Africa during the rainy season. Because of the unusual presentation of this disease in Africa, clinical and microbiological diagnosis of imported melioidosis from this continent can be very elusive.

  2. West Africa prepares for busy season. [Petroleum exploration in West Africa

    SciTech Connect

    Not Available

    1982-06-20

    Although there has been a decrease in oil prices, activity along coastal West Africa has tended to increase, with emphasis on field development and production. Because of a world-wide surplus of petroleum, Nigeria has had to cut production by more than half and offshore operations have been affected also. Off the coast of Gabon exploration activity has increased with numerous wildcat rigs which are potentially highly productive. Overall production in Gabon has decreased slightly since 1980. The People's Republic of the Congo, on the other hand, has increased productivity due to new successful fields, while in the Angola/Cabinda area new offshore programs are forming. Production and exploration increases are also expected for Ghana, Zaire, Cameroon, and South Africa. (JBF)

  3. Markets, Climate Change and Food Security in West Africa

    NASA Technical Reports Server (NTRS)

    Brown, Molly E.; Hintermann, Beat; Higgins, Nathaniel

    2009-01-01

    West Africa is one of the most food insecure regions of the world. Sharply increased food and energy prices in 2008 brought the role of markets in food access and availability around the world into the spotlight, particularly in urban areas. The period of high prices had the immediate consequence of sharply increasing the number of hungry people in the region without boosting farmer incomes significantly. In this article, the interaction between markets, food prices, agricultural technology and development is explored in the context of West Africa. To improve food security in West Africa, sustained commitment to investment in the agriculture sector will be needed to provide some protection against global swings in both production and world markets. Climate change mitigation programs are likely to force global energy and commodity price increases in the coming decades, putting pressure on regions like West Africa to produce more food locally to ensure stability in food security for the most vulnerable.

  4. Ancient west Eurasian ancestry in southern and eastern Africa

    PubMed Central

    Pickrell, Joseph K.; Patterson, Nick; Loh, Po-Ru; Lipson, Mark; Berger, Bonnie; Stoneking, Mark; Pakendorf, Brigitte; Reich, David

    2014-01-01

    The history of southern Africa involved interactions between indigenous hunter–gatherers and a range of populations that moved into the region. Here we use genome-wide genetic data to show that there are at least two admixture events in the history of Khoisan populations (southern African hunter–gatherers and pastoralists who speak non-Bantu languages with click consonants). One involved populations related to Niger–Congo-speaking African populations, and the other introduced ancestry most closely related to west Eurasian (European or Middle Eastern) populations. We date this latter admixture event to ∼900–1,800 y ago and show that it had the largest demographic impact in Khoisan populations that speak Khoe–Kwadi languages. A similar signal of west Eurasian ancestry is present throughout eastern Africa. In particular, we also find evidence for two admixture events in the history of Kenyan, Tanzanian, and Ethiopian populations, the earlier of which involved populations related to west Eurasians and which we date to ∼2,700–3,300 y ago. We reconstruct the allele frequencies of the putative west Eurasian population in eastern Africa and show that this population is a good proxy for the west Eurasian ancestry in southern Africa. The most parsimonious explanation for these findings is that west Eurasian ancestry entered southern Africa indirectly through eastern Africa. PMID:24550290

  5. Phytoplankton off the West Coast of Africa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Just off the coast of West Africa, persistent northeasterly trade winds often churn up deep ocean water. When the nutrients in these deep waters reach the ocean's surface, they often give rise to large blooms of phytoplankton. This image of the Mauritanian coast shows swirls of phytoplankton fed by the upwelling of nutrient-rich water. The scene was acquired by the Medium Resolution Imaging Spectrometer (MERIS) aboard the European Space Agency's ENVISAT. MERIS will monitor changes in phytoplankton across Earth's oceans and seas, both for the purpose of managing fisheries and conducting global change research. NASA scientists will use data from this European instrument in the Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) program. The mission of SIMBIOS is to construct a consistent long-term dataset of ocean color (phytoplankton abundance) measurements made by multiple satellite instruments, including the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and the Moderate-Resolution Imaging Spectroradiometer (MODIS). For more information about MERIS and ENVISAT, visit the ENVISAT home page. Image copyright European Space Agency

  6. Illicit Drug Trafficking in West Africa -- Primary Surveillance Radar Introduction

    DTIC Science & Technology

    2012-03-22

    social cohesion.9 West African Trade West Africa has a long history of trade . This was not restricted to the export of slaves and tropical...Kola stimulant, cannabis and alcohol were all legally traded between Europe, the Middle East and the Sahara. Given West Africa’s long history of...West African Membership in Multilateral Anti-Crime Agreements or Bodies West African nations know and understand the problem of illicit trade but

  7. First carboniferous conulariids from Niger (west Africa)

    NASA Astrophysics Data System (ADS)

    Babcock, L. E.; Lang, J.; Yahaya, M.

    1995-01-01

    Two new conulariid species, Paraconularia feldmanni sp. nov. and P. sahara sp. nov., are described from the Lower Carboniferous (Visean) Talak Formation of northern Niger. These are the first example of the genus Paraconularia to be reported from Africa and the first Carboniferous conulariids from that continent to be assigned to species level. Previously reported Carboniferous conulariids from Africa were collected from Morocco, assigned to other genera, and left in open nomenclature. Paraconularia is interpreted to have been cosmopolitan by the Early Carboniferous, and is the dominant genus in most assemblages of Carboniferous conulariids.

  8. Narco-Pipeline to West Africa

    DTIC Science & Technology

    2009-04-01

    examined are: language, colonization, religion, health , literacy , and economic indicators. Language & Colonization Language, the foundation of...AFRICA SOUTH OF THE SAHARA 2006”, p. 882. 12 13 Health Literacy & Economic Indicators In South America nearly 90 per cent of all adults can

  9. Mapping and analyzing urban growth in West Africa

    NASA Astrophysics Data System (ADS)

    Adhikari, P.; de Beurs, K. M.

    2014-12-01

    Africa has experienced the highest urban growth (~3.5% per year) in the developing world. West Africa in particular has seen significant urban growth mainly driven by the high natural population growth rate and the increasing percentage of population moving to urban areas. Urban growth in West Africa is expected to continue in decades to come. This study uses Landsat data at five different time steps (1970, 1980, 1990, 2000, and 2010) to map four cities from four different eco-regions of West Africa since the early 1970s. The selected four cities, Kumasi in Ghana, Abuja in Nigeria, Tahoua in Niger and Ouagadoughou in Burkina Faso, are some of the fastest growing cities in the region. We selected the cities in the following ecoregions: Eastern Guinean Forest, Guinean Forest-Savanna Mosaic, Sahelian Acacia Savanna and West Sudanian Savanna. We hypothesize that urban growth in West Africa is different compared to the other parts of the world primarily due to the dependency of about 60 percent of active labor force on subsistence agriculture in the region. As agriculture productivity is dependent on favorable climatic conditions (i.e., good rainfall, suitable temperature), any variability in climate impends the livelihood of subsistence farmers triggering the movements of more people towards the cities. Therefore, studying urban growth based on ecoregions help to better explain the urban development in West Africa. After mapping the urban areas, this study makes a comparative analysis of the temporal and spatial pattern of the urban growths across the ecoregions in West Africa.

  10. Kimberlites of the Man craton, West Africa

    NASA Astrophysics Data System (ADS)

    Skinner, E. M. W.; Apter, D. B.; Morelli, C.; Smithson, N. K.

    2004-09-01

    The Man craton in West Africa is an Archaean craton formerly joined to the Guyana craton (South America) that was rifted apart in the Mesozoic. Kimberlites of the Man craton include three Jurassic-aged clusters in Guinea, two Jurassic-aged clusters in Sierra Leone, and in Liberia two clusters of unknown age and one Neoproterozoic cluster recently dated at ˜800 Ma. All of the kimberlites irrespective of age occur as small pipes and prolific dykes. Some of the Banankoro cluster pipes in Guinea, the Koidu pipes in Sierra Leone and small pipes in the Weasua cluster in Liberia contain hypabyssal-facies kimberlite and remnants of the so-called transitional-facies and diatreme-facies kimberlite. Most of the Man craton kimberlites are mineralogically classified as phlogopite kimberlites, although potassium contents are relatively low. They are chemically similar to mica-poor Group 1A Southern African examples. The Jurassic kimberlites are considered to represent one province of kimberlites that track from older bodies in Guinea (Droujba 153 Ma) to progressively younger kimberlites in Sierra Leone (Koidu, 146 Ma and Tongo, 140 Ma). The scarcity of diatreme-facies kimberlites relative to hypabyssal-facies kimberlites and the presence of the so-called transitional-facies indicate that the pipes have been eroded down to the interface between the root and diatreme zones. From this observation, it is concluded that extensive erosion (1-2 km) has occurred since the Jurassic. In addition to erosion, the presence of abundant early crystallizing phlogopite is considered to have had an effect on the relatively small sizes of the Man craton kimberlites.

  11. [Familial modernity and plurality in West Africa].

    PubMed

    Vimard, P

    1993-01-01

    Changes in the family system of West Africa have accompanied the numerous economic, demographic, and social changes occurring after colonization and especially since independence. This work uses monographic data from Togo and the Ivory Coast to examine to what degree lineage structures have been supplanted by autonomy of domestic groups and the emergence of new forms of family organization, to what extent intrafamilial social relations and behavior have been affected by the market economy, and whether the spread of western culture has led to a plurality of family models. The integration of rural African societies into market economies has been achieved primarily through their progressive absorption into plantation economic systems. Appropriation of manpower by plantation economies has largely removed control over the reproduction and use of the labor force from the lineage to a smaller family group. Individual relationships are undergoing redefinition within the new structures of socially and economically autonomous domestic groups. Lineages have lost control over matrimonial alliances; marriage has ceased to represent an exchange between social groups and has become an alliance between individuals. The weakened integration of couples into traditional family structures has increased the instability of unions. The emergence of the domestic group as an autonomous institution has engendered a redefinition of roles and practices within families, and new forms of social relations between the husbands, wives, and their children. Economic and social roles today depend less on belonging to extended structures such as lineages or age classes and more on nonpredetermined factors susceptible to change that characterize the family and economic position, such as educational level, marital status, and occupation. Changes in power relations between spouses have led to greater independence but also greater precariousness in women;s positions. The status of children has undergone a

  12. The Lion in West Africa Is Critically Endangered

    PubMed Central

    Henschel, Philipp; Coad, Lauren; Burton, Cole; Chataigner, Beatrice; Dunn, Andrew; MacDonald, David; Saidu, Yohanna; Hunter, Luke T. B.

    2014-01-01

    The African lion has declined to <35,000 individuals occupying 25% of its historic range. The situation is most critical for the geographically isolated populations in West Africa, where the species is considered regionally endangered. Elevating their conservation significance, recent molecular studies establish the genetic distinctiveness of West and Central African lions from other extant African populations. Interventions to save West African lions are urgently required. However formulating effective conservation strategies has been hampered by a lack of data on the species' current distribution, status, and potential management deficiencies of protected areas (PAs) harboring lions. Our study synthesized available expert opinion and field data to close this knowledge gap, and formulate recommendations for the conservation of West African lions. We undertook lion surveys in 13 large (>500 km2) PAs and compiled evidence of lion presence/absence for a further eight PAs. All PAs were situated within Lion Conservation Units, geographical units designated as priority lion areas by wildlife experts at a regional lion conservation workshop in 2005. Lions were confirmed in only 4 PAs, and our results suggest that only 406 (273–605) lions remain in West Africa, representing <250 mature individuals. Confirmed lion range is estimated at 49,000 km2, or 1.1% of historical range in West Africa. PAs retaining lions were larger than PAs without lions and had significantly higher management budgets. We encourage revision of lion taxonomy, to recognize the genetic distinctiveness of West African lions and highlight their potentially unique conservation value. Further, we call for listing of the lion as critically endangered in West Africa, under criterion C2a(ii) for populations with <250 mature individuals. Finally, considering the relative poverty of lion range states in West Africa, we call for urgent mobilization of investment from the international community to assist range

  13. The lion in West Africa is critically endangered.

    PubMed

    Henschel, Philipp; Coad, Lauren; Burton, Cole; Chataigner, Beatrice; Dunn, Andrew; MacDonald, David; Saidu, Yohanna; Hunter, Luke T B

    2014-01-01

    The African lion has declined to <35,000 individuals occupying 25% of its historic range. The situation is most critical for the geographically isolated populations in West Africa, where the species is considered regionally endangered. Elevating their conservation significance, recent molecular studies establish the genetic distinctiveness of West and Central African lions from other extant African populations. Interventions to save West African lions are urgently required. However formulating effective conservation strategies has been hampered by a lack of data on the species' current distribution, status, and potential management deficiencies of protected areas (PAs) harboring lions. Our study synthesized available expert opinion and field data to close this knowledge gap, and formulate recommendations for the conservation of West African lions. We undertook lion surveys in 13 large (>500 km²) PAs and compiled evidence of lion presence/absence for a further eight PAs. All PAs were situated within Lion Conservation Units, geographical units designated as priority lion areas by wildlife experts at a regional lion conservation workshop in 2005. Lions were confirmed in only 4 PAs, and our results suggest that only 406 (273-605) lions remain in West Africa, representing <250 mature individuals. Confirmed lion range is estimated at 49,000 km², or 1.1% of historical range in West Africa. PAs retaining lions were larger than PAs without lions and had significantly higher management budgets. We encourage revision of lion taxonomy, to recognize the genetic distinctiveness of West African lions and highlight their potentially unique conservation value. Further, we call for listing of the lion as critically endangered in West Africa, under criterion C2a(ii) for populations with <250 mature individuals. Finally, considering the relative poverty of lion range states in West Africa, we call for urgent mobilization of investment from the international community to assist range

  14. Regional paleogeographic evolution of west Africa: Implications for hydrocarbon exploration

    SciTech Connect

    Hempton, M.R.; Rosen, M.A.; Coughlin, R.M.; Scardina, A.D.; Hagen, E.S.; Nordstrom, P.J. )

    1991-03-01

    New paleogeographic reconstructions of west African continental margins provide a regional framework to contrast differences in hydrocarbon habitat and tectonostratigraphic style. Five regional provinces are delineated: (1) Northwest Africa margin from mauritania to Sierra Leone, (2) Transform margin from Liberia to Benin, (3) Niger delta of Nigeria, Cameroon, and Equatorial Guinea, (4) South Atlantic Salt basin margin from Cameroon to Angola, and (5) Southwest Africa margin of Namibia and South Africa. Computer-constrained paleogeographic reconstructions based on exploration data depict the separation of west Africa from South and North America during the Late Triassic to the present along three rift systems. In northwest Africa rifting began in the Late Triassic associated with the opening of the Central Atlantic. In southwest Africa rifting began between the southern tips of Africa and South America in the Early Cretaceous (Valanginian) and propagated northward to the Benue Trough, a broad zone of left-lateral shear and extensional basins that began to open in the Aptian. Between these two rift systems, the Transform margin rift system initiated in the Early Cretaceous (Barremain) as a wrench-fault dominated eastward extension of the Proto-Caribbean ocean that propagated to the Benue Trough by the middle Albian. The most important variables affecting the tectonostratigraphic and hydrocarbon evolution of the west African margins include (1) the geometry, kinematics, and duration of rifting; (2) distribution of rift basins relative to paleoclimate zones (which affects the deposition of lacustrine source rocks and evaporites while influencing the type and quantity of sediment derived from land); (3) sea-level fluctuations; and (4) distribution of deltaic and turbiditic depocenters.

  15. Regional paleogeographic evolution of West Africa: Implications for hydrocarbon exploration

    SciTech Connect

    Hempton, M.R. )

    1993-11-01

    New paleogeographic reconstructions of west African continental margins provide a regional framework to contrast differences in hydrocarbon habitat and tectonostratigraphic style. The framework consists of five regional provinces: (1) northwest Africa margin from Mauritania to Sierra Leone, (2) transform margin from Libera to Benin, (3) Niger Delta of Nigeria, Cameroon, and equatorial Guinea, (4) South Atlantic Salt Basin margin from Cameroon to Angola, and (5) southwest Africa margin of Namibia and South Africa. Computer-constrained paleogeographic reconstructions based on exploration data depict the separation of west Africa from South and North America along three rift systems during the Late Triassic to the Holocene. In northwest Africa, rifting began in the Late Triassic associated with the opening of the central Atlantic. In southwest Africa, rifting began between the southern tips of Africa and South America in the Early Cretaceous and propagated northward to the Benue trough, a broad zone of left-lateral shear and extensional basins that began to open in the Aptian. Between these two rift systems, the transform margin rift system initiated in the Early Cretaceous (Barremian) as a wrench-fault-dominated eastward extension of the Proto-Caribbean ocean that propagated to the Benue trough by the middle Albian. The most important variables affecting the tectonostratigraphic and hydrocarbon evolution of the west African margins include (1) the geometry, kinematics, and duration of rifting, (2) distribution of rift basins relative to paleoclimate zones (which affects the deposition of lacustrine source rocks and evaporites while influencing the type and quantity of sediment derived from land), (3) sea level fluctuations, and (4) distribution of deltaic and turbiditic depocenters.

  16. Child Trafficking in West Africa: Policy Responses. Innocenti Insight.

    ERIC Educational Resources Information Center

    United Nations Children's Fund, Florence (Italy). Innocenti Research Centre.

    This report examines policy responses and programming trends to combat the growing specter of child trafficking, focusing on the region of west and central Africa where strenuous advocacy efforts by UNICEF and its partners have helped to bring this problem to national and international attention. The report focuses on policy trends on child…

  17. Teaching in West Africa: Dig beneath the Surface

    ERIC Educational Resources Information Center

    Briam, Carol

    2007-01-01

    In this article, the author shares her experience teaching English to adult learners at the American Cultural Center in Dakar, Senegal, a poor, primarily Muslim country and former French colony in West Africa. Her class was composed of about 30 students, whose age ranged from about 18 to 50. They were mostly men and mostly Senegalese, along with a…

  18. Logical Demonomy Among the Ewe in West Africa

    ERIC Educational Resources Information Center

    Dzobo, N. K.

    1974-01-01

    Examines the indigenous pattern of moral behavior among the Ewe, an ethnic and linguistic group in West Africa, and assesses its role in moral education within the African context. The author develops a conceptual framework he calls "logical demonomy" that he uses to define the Ewe system of moral laws. (JT)

  19. Agricultural Adaptations to Climate Changes in West Africa

    NASA Astrophysics Data System (ADS)

    Guan, K.; Sultan, B.; Lobell, D. B.; Biasutti, M.; Piani, C.; Hammer, G. L.; McLean, G.

    2014-12-01

    Agricultural production in West Africa is highly vulnerable to climate variability and change and a fast growing demand for food adds yet another challenge. Assessing possible adaptation strategies of crop production in West Africa under climate change is thus critical for ensuring regional food security and improving human welfare. Our previous efforts have identified as the main features of climate change in West Africa a robust increase in temperature and a complex shift in the rainfall pattern (i.e. seasonality delay and total amount change). Unaddressed, these robust climate changes would reduce regional crop production by up to 20%. In the current work, we use two well-validated crop models (APSIM and SARRA-H) to comprehensively assess different crop adaptation options under future climate scenarios. Particularly, we assess adaptations in both the choice of crop types and management strategies. The expected outcome of this study is to provide West Africa with region-specific adaptation recommendations that take into account both climate variability and climate change.

  20. Sanaga Sud field - Offshore Cameroon, west Africa

    SciTech Connect

    Pauken, R.J. )

    1990-09-01

    The Sanaga Sud field, offshore Cameroon, is located just northwest of the coastal town of Kribi in the northern part of the Douala basin. The discovery well, Sanaga Sud A-1, was drilled in 1979 to test an apparent horst block that contained a prominent horizontal seismic amplitude. The Douala basin is one of a series of passive margin basins located along the coastline of central and southern Africa, and formed during the rifting of Africa and South America during the Early Cretaceous. Drilling results showed that the amplitude was a gas/water contact. Two appraisal wells, SSA-2 and SSA-3, were drilled in 1981. All three wells tested gas and condensate. Total recoverable hydrocarbons for the field are estimated to be approximately 1 tcf of gas. The trap in this field is composed of tilted and rotated fault blocks composed of interbedded Aptian to Albian sandstones, siltstones, and shales. The fault blocks were truncated by erosion (breakup unconformity) and later buried by a considerable thickness of onlapping Upper Cretaceous and Tertiary shale. The late Albian erosional unconformity forms the top of the trap over most of the field. Geochemical studies indicate a Lower Cretaceous source for the hydrocarbons. The gross pay thickness averages 250 m with an average porosity of 23% and an average permeability of 142 md. Reservoir lithologies range from well-sorted, massive sandstones to poorly sorted fine sandstones and siltstones containing shaly laminations that are carbonaceous and micaceous. The field is located predominantly in Block PH-38, but part of the field is in the Londji concession. Mobil Producing Cameroon, Inc., is the operator of PH-38 and Total Exploration and Production Cameroon is the operator of the Londji concession.

  1. West Africa land use land cover time series

    USGS Publications Warehouse

    Tappan, G. Gray; Cushing, W. Matthew; Cotillon, Suzanne E.; Mathis, Melissa L.; Hutchinson, John A.; Dalsted, K. J.

    2016-01-01

    The West Africa Land Use Dynamics Project provides AGRHYMET and its 17 participating countries a comprehensive two-kilometer (2-km) resolution land use land cover (LULC) dataset of the region for three time periods; 1975, 2000, and 2013. Hundreds of Landsat images were visually interpreted to develop a 2-km LULC dataset for each of the three time periods. To assist in validating the interpretations, thousands of aerial photographs and high-resolution satellite images were used. From the initial datasets produced by national teams, the U.S. Geological Survey (USGS) conducted an independent, detailed review of the interpretations. In concurrence with the respective country teams, the data have been revised to produce an accurate and consistent LULC assessment from within the countries and respective transboundary areas. This West Africa Land Use Dynamics Project represents an effort to document and quantify the impacts of change in both time and space, of the environmental and land resource trends across West Africa. The project was carried out through the AGRHYMET Regional Center in Niamey, Niger, in partners from 17 participating countries, the Sahel Institute (INSAH), the USGS Earth Resources Observation and Science (EROS), and with major support from the U.S. Agency for International Development (USAID) West Africa Regional Program. The overarching goal of the West Africa Land Use Dynamics Project is to promote the awareness of the trends and use of spatial information about natural resource trends among national and regional decision-makers. For a complete description of project visit https://eros.usgs.gov/westafrica

  2. New vectors of Rift Valley fever in West Africa.

    PubMed Central

    Fontenille, D.; Traore-Lamizana, M.; Diallo, M.; Thonnon, J.; Digoutte, J. P.; Zeller, H. G.

    1998-01-01

    After an outbreak of Rift Valley fever in Southern Mauritania in 1987, entomologic studies were conducted in a bordering region in Sénégal from 1991 to 1996 to identify the sylvatic vectors of Rift Valley fever virus. The virus was isolated from the floodwater mosquitoes Aedes vexans and Ae. ochraceus. In 1974 and 1983, the virus had been isolated from Ae. dalzieli. Although these vectors differ from the main vectors in East and South Africa, they use the same type of breeding sites and also feed on cattle and sheep. Although enzootic vectors have now been identified in West Africa, the factors causing outbreaks remain unclear. PMID:9621201

  3. New vectors of Rift Valley fever in West Africa.

    PubMed

    Fontenille, D; Traore-Lamizana, M; Diallo, M; Thonnon, J; Digoutte, J P; Zeller, H G

    1998-01-01

    After an outbreak of Rift Valley fever in Southern Mauritania in 1987, entomologic studies were conducted in a bordering region in Sénégal from 1991 to 1996 to identify the sylvatic vectors of Rift Valley fever virus. The virus was isolated from the floodwater mosquitoes Aedes vexans and Ae. ochraceus. In 1974 and 1983, the virus had been isolated from Ae. dalzieli. Although these vectors differ from the main vectors in East and South Africa, they use the same type of breeding sites and also feed on cattle and sheep. Although enzootic vectors have now been identified in West Africa, the factors causing outbreaks remain unclear.

  4. Energy Reform for West Africa in Climate Change Crisis Era

    NASA Astrophysics Data System (ADS)

    Nwokocha, C.; Kasei, R.

    2009-04-01

    UNFCCC reports indicate that those who are least responsible for climate change are also the most vulnerable to its projected impacts. In no place is this more evident than in Sub-Saharan Africa, where greenhouse gas (GHG) emissions are negligible from a global scale. In Africa, energy demands could be the major factor that may lead to the increase of its emissions in the very near future. Forests are being lost for domestic energy, Oil produced energy increases carbon foot prints and Hydropower is unreliable due to uncertainties in rainfall patterns. By 2004, the energy consumption mix of West Africa was dominated by oil (58%) followed by natural gas (38%) and hydroelectric (8%) with coal and other energy forms not part of the mix. (Energy Information Administration, 2007). Rainfall and Global radiation using the Armstrong method was analyzed for sites in Nigeria and Ghana. A cost-benefit of the energy productions is presented.

  5. Implementing haemophilia care in Senegal, West Africa.

    PubMed

    Diop, S; Seck, M; Sy-Bah, D; Faye, B F; Sow-Ndoye, A; Gueye, Y B; Senghor, A B; Sall-Fall, A; Toure-Fall, A O; Dièye, T N; Thiam, D; Diakhate, L

    2014-01-01

    Despite significant progres on haemophilia care in developed world, this disease remains unknown in many sub-Saharan African countries. The objectives of this article were to report Senegalese experience on the management of haemophilia care through 18 years of follow-up. This cohort study included 140 patients (127 haemophilia A, 13 haemophilia B), followed in Dakar's haemophilia treatment centre from 1995 to 2012. Our study reported a prevalence of 2.3/100,000 male births, accounting for 11.6% of what is expected in Senegal. From the period 1995-2003 to 2004-2012, significant progress was seen including 67.9% increase in new patient's identification, 11.3 years reduction in mean age at diagnosis (from 15.5 to 4.2 years), lower mortality rate (from 15.3% to 6.8%) and age at death evolved from 6.5 to 23.3 years. Of the 50 haemophilia A patients who were tested for inhibitor presence, 10 were positive (eight severe and two moderate) that is prevalence of 20%. All patients were low responders since inhibitor titre was between 1.5 and 3.8 BU. Disabilities were seen in 36.5% of patients above 20 years old who had musculoskeletal sequels and 39% had no scholar or professional activities in our setting. Implementing haemophilia care in sub-Saharan Africa is a great challenge as this disease is not yet counted in national health problems in many countries. Lessons learned from this study show a significant improvement in diagnosis and prognosis parameters. This emphasizes the needs to set up such follow-up initiatives and to enhance medical and lay cooperation for better results.

  6. Potential Climate Effects of Dust Aerosols' over West Africa

    NASA Astrophysics Data System (ADS)

    JI, Z.; Wang, G.; Pal, J. S.; Yu, M.

    2014-12-01

    Climate in West Africa is under the influence of the West African monsoon circulation and mineral dust emitted from the Sahara desert (which is the world's largest source of mineral dust emission). Dust aerosols alter the atmospheric radiative fluxes and act as cloud condensation nuclei in the process of emission, transportation and deposition. However, our understanding regarding how dust aerosols influence the present-day and future climate of West Africa is very limited. In this study, a regional climate model RegCM4.3.4-CLM4.5 is used to investigate the potential climatic effects of dust aerosols both in present (1981-2000) and future (2081-2100) periods over WA. First, the model performance and dust climatic effects are evaluated. The contribution of dust climatic effects under RCP8.5 scenario and their confounding effects with land use change are assessed. Our results indicate that the model can reproduce with reasonable accuracy the spatial and temporal distribution of climatology, aerosol optical depth and surface concentration over WA. The shortwave radiative forcing of dust is negative in the surface and positive in the atmosphere, with greater changes in JJA and MAM compared to those in SON and DJF. Over most of West Africa, cooling is the dominant effect on temperature. Their impact on precipitation features a dipole pattern, with decrease in the north and increase in the south of West Africa. Despite the dust-induced decrease of precipitation amount, dusts cause extreme precipitation to increase. To evaluate the uncertainties surrounding our modeling results, sensitivity experiments driven by ICBC from MIROC-ESM and CESM and their dynamic downscaling results are used for comparisons. Results from these sensitivity experiments indicate that the impact of dust aerosols on present and future climate is robust.

  7. Underdevelopment: Major Cause of Insecurity in West Africa

    DTIC Science & Technology

    2005-03-03

    dependent on such positive agricultural policies which aim at eradicating hunger and food insecurity , the presence of which may cause instability within...which could result in food insecurity and thus conflict. As already mentioned, countries in West Africa mainly export primary products which generally...deforestation. Deforestation also makes agricultural production unsustainable which affects both 13 food and cash crop production. Food insecurity brings

  8. Intense convection over West Africa during AMMA SOP3 experiment

    NASA Astrophysics Data System (ADS)

    Lenouo, André; Sall, Saïdou Moustapha; Badiane, Daouda; Gaye, Amadou Thierno; Kamga Mkankam, F.

    2016-11-01

    ERA-Interim product from the European Center for Medium-Range Weather Forecast (ECMWF) assimilation of African Monsoon Multidisciplinary Analysis (AMMA) resources, Meteosat satellite images, and synoptic observations were used to study local- and regional-scale environments associated with intense convective systems during the AMMA-SOP3 experiment over West Africa in the Northern Hemisphere of summer 2006. The convective system, from the 21st to 23rd of August 2006, was more active at 0000 and 1800 UTC showing diurnal cycle of deep convection over West Africa where the African easterly waves (AEWs) are developed downstream. Downstream barotropic and baroclinic energy conversions associated with strong AEWs are important for the maintenance of AEW activity in West Africa. Barotropic energy conversions dominate south of the African easterly jet (AEJ), while baroclinic energy conversions are most important north of the AEJ. From a dynamical viewpoint, the low-level vorticity presents strong positive values over the sea and Sahara zone, indicating that exists on the cyclonic shear side of the African easterly jet, which is consistent with baroclinic growth. The 925-hPa equivalent potential temperature structure show a maximum over the Sahara which corresponds to the depression observed in this region. A mosaic of three hourly infrared (IR) satellite images, depicts a very distinct signal from an initial region of convection, developing through several stages and moving off the African coast. These observations, along with those available from the World Weather Watch, provide an opportunity to carry out numerical weather prediction (NWP) studies over West Africa utilizing high resolution limited area models.

  9. Laboratory Response to Ebola - West Africa and United States.

    PubMed

    Sealy, Tara K; Erickson, Bobbie R; Taboy, Céline H; Ströher, Ute; Towner, Jonathan S; Andrews, Sharon E; Rose, Laura E; Weirich, Elizabeth; Lowe, Luis; Klena, John D; Spiropoulou, Christina F; Rayfield, Mark A; Bird, Brian H

    2016-07-08

    The 2014-2016 Ebola virus disease (Ebola) epidemic in West Africa highlighted the need to maintain organized laboratory systems or networks that can be effectively reorganized to implement new diagnostic strategies and laboratory services in response to large-scale events. Although previous Ebola outbreaks enabled establishment of critical laboratory practice safeguards and diagnostic procedures, this Ebola outbreak in West Africa highlighted the need for planning and preparedness activities that are better adapted to emerging pathogens or to pathogens that have attracted little commercial interest. The crisis underscored the need for better mechanisms to streamline development and evaluation of new diagnostic assays, transfer of material and specimens between countries and organizations, and improved processes for rapidly deploying health workers with specific laboratory expertise. The challenges and events of the outbreak forced laboratorians to examine not only the comprehensive capacities of existing national laboratory systems to recognize and respond to events, but also their sustainability over time and the mechanisms that need to be pre-established to ensure effective response. Critical to this assessment was the recognition of how response activities (i.e., infrastructure support, logistics, and workforce supplementation) can be used or repurposed to support the strengthening of national laboratory systems during the postevent transition to capacity building and recovery. This report compares CDC's domestic and international laboratory response engagements and lessons learned that can improve future responses in support of the International Health Regulations and Global Health Security Agenda initiatives.The activities summarized in this report would not have been possible without collaboration with many U.S. and international partners (http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/partners.html).

  10. Ebola virus disease outbreak - West Africa, September 2014.

    PubMed

    2014-10-03

    CDC is assisting ministries of health and working with other organizations to control and end the ongoing outbreak of Ebola virus disease (Ebola) in West Africa. The updated data in this report were compiled from ministry of health situation reports and World Health Organization (WHO) sources. Total case counts include all suspected, probable, and confirmed cases as defined by each country. These data reflect reported cases, which make up an unknown proportion of all actual cases. The data also reflect reporting delays that might vary from country to country.

  11. Update: Ebola virus disease outbreak--West Africa, October 2014.

    PubMed

    2014-10-31

    CDC is assisting ministries of health and working with other organizations to control and end the ongoing outbreak of Ebola virus disease (Ebola) in West Africa. The updated data in this report were compiled from situation reports from the Guinea Interministerial Committee for Response Against the Ebola Virus and the World Health Organization, the Liberia Ministry of Health and Social Welfare, and the Sierra Leone Ministry of Health and Sanitation. Total case counts include all suspected, probable, and confirmed cases as defined by each country. These data reflect reported cases, which make up an unknown proportion of all actual cases and reporting delays that vary from country to country.

  12. Testing Modeling Assumptions in the West Africa Ebola Outbreak

    NASA Astrophysics Data System (ADS)

    Burghardt, Keith; Verzijl, Christopher; Huang, Junming; Ingram, Matthew; Song, Binyang; Hasne, Marie-Pierre

    2016-10-01

    The Ebola virus in West Africa has infected almost 30,000 and killed over 11,000 people. Recent models of Ebola Virus Disease (EVD) have often made assumptions about how the disease spreads, such as uniform transmissibility and homogeneous mixing within a population. In this paper, we test whether these assumptions are necessarily correct, and offer simple solutions that may improve disease model accuracy. First, we use data and models of West African migration to show that EVD does not homogeneously mix, but spreads in a predictable manner. Next, we estimate the initial growth rate of EVD within country administrative divisions and find that it significantly decreases with population density. Finally, we test whether EVD strains have uniform transmissibility through a novel statistical test, and find that certain strains appear more often than expected by chance.

  13. Testing Modeling Assumptions in the West Africa Ebola Outbreak

    PubMed Central

    Burghardt, Keith; Verzijl, Christopher; Huang, Junming; Ingram, Matthew; Song, Binyang; Hasne, Marie-Pierre

    2016-01-01

    The Ebola virus in West Africa has infected almost 30,000 and killed over 11,000 people. Recent models of Ebola Virus Disease (EVD) have often made assumptions about how the disease spreads, such as uniform transmissibility and homogeneous mixing within a population. In this paper, we test whether these assumptions are necessarily correct, and offer simple solutions that may improve disease model accuracy. First, we use data and models of West African migration to show that EVD does not homogeneously mix, but spreads in a predictable manner. Next, we estimate the initial growth rate of EVD within country administrative divisions and find that it significantly decreases with population density. Finally, we test whether EVD strains have uniform transmissibility through a novel statistical test, and find that certain strains appear more often than expected by chance. PMID:27721505

  14. Testing Modeling Assumptions in the West Africa Ebola Outbreak.

    PubMed

    Burghardt, Keith; Verzijl, Christopher; Huang, Junming; Ingram, Matthew; Song, Binyang; Hasne, Marie-Pierre

    2016-10-10

    The Ebola virus in West Africa has infected almost 30,000 and killed over 11,000 people. Recent models of Ebola Virus Disease (EVD) have often made assumptions about how the disease spreads, such as uniform transmissibility and homogeneous mixing within a population. In this paper, we test whether these assumptions are necessarily correct, and offer simple solutions that may improve disease model accuracy. First, we use data and models of West African migration to show that EVD does not homogeneously mix, but spreads in a predictable manner. Next, we estimate the initial growth rate of EVD within country administrative divisions and find that it significantly decreases with population density. Finally, we test whether EVD strains have uniform transmissibility through a novel statistical test, and find that certain strains appear more often than expected by chance.

  15. Trends and Issues in Vocational Technical Education in Francophone West Africa.

    ERIC Educational Resources Information Center

    Kogoe, Akrima

    Francophone West Africa has committed itself to the goal of universal formal education as the most effective method of insuring rapid economic and national development. (Francophone West Africa is composed of Senegal, Mauritania, Guinea, Mali, Ivory Coast, Togo, Benin, Niger, and Burkina-Faso.) The costly investments of limited fiscal resources in…

  16. Mathematical modeling of the West Africa Ebola epidemic

    PubMed Central

    Chretien, Jean-Paul; Riley, Steven; George, Dylan B

    2015-01-01

    As of November 2015, the Ebola virus disease (EVD) epidemic that began in West Africa in late 2013 is waning. The human toll includes more than 28,000 EVD cases and 11,000 deaths in Guinea, Liberia, and Sierra Leone, the most heavily-affected countries. We reviewed 66 mathematical modeling studies of the EVD epidemic published in the peer-reviewed literature to assess the key uncertainties models addressed, data used for modeling, public sharing of data and results, and model performance. Based on the review, we suggest steps to improve the use of modeling in future public health emergencies. DOI: http://dx.doi.org/10.7554/eLife.09186.001 PMID:26646185

  17. A case of Plasmodium ovale malaria imported from West Africa.

    PubMed

    Kang, Yunjung; Yang, Jinyoung

    2013-04-01

    Malaria is a parasitic infection caused by Plasmodium species. Most of the imported malaria in Korea are due to Plasmodium vivax and Plasmodium falciparum, and Plasmodium ovale infections are very rare. Here, we report a case of a 24-year-old American woman who acquired P. ovale while staying in Ghana, West Africa for 5 months in 2010. The patient was diagnosed with P. ovale malaria based on a Wright-Giemsa stained peripheral blood smear, Plasmodium genus-specific real-time PCR, Plasmodium species-specific nested PCR, and sequencing targeting 18S rRNA gene. The strain identified had a very long incubation period of 19-24 months. Blood donors who have malaria with a very long incubation period could be a potential danger for propagating malaria. Therefore, we should identify imported P. ovale infections not only by morphological findings but also by molecular methods for preventing propagation and appropriate treatment.

  18. Socioeconomic consequences of blinding onchocerciasis in west Africa.

    PubMed Central

    Evans, T. G.

    1995-01-01

    Onchocerciasis or river blindness, a major cause of irreversible blindness among adults, has been the focus of international disease control efforts for over 20 years in West Africa. This paper employs the international classification of impairment, disability and handicap (ICIDH) to interpret results from a field study to assess the socioeconomic consequences of onchocerciasis in Guinea in 1987. In a sample of 136 blind, 94 visually impaired and 89 well-sighted persons, decreasing visual acuity is strongly associated with mobility, occupational and marital handicaps. Individual, household and disease correlates were explored. The implications of these findings for the ICIDH concept of handicap are discussed with particular emphasis on the need to extend analysis beyond the individual when assessing the socioeconomic consequences of disabling disease. PMID:7554022

  19. How many rifts are there in West Africa?

    NASA Astrophysics Data System (ADS)

    Freeth, S. J.

    1984-02-01

    The West African Rift System has, for the last ten years, been thought to consist of five interconnected rifts extending from the Gulf of Guinea deep into the heart of Africa. Careful re-examination of the geophysical evidence makes it quite clear that there are only three interconnected rifts in West Africa; the Lower Benue Rift which extends to the northeast from the Gulf of Guinea to a triple junction near Chum, and the Gongola and Yola Rifts which extend to the north and east, respectively, from the Chum triple junction. These three rifts opened during the earlier part of the Mesozoic and were subsequently filled with Cretaceous sediments. The evidence for two further rifts, the Ati Rift and the Fort Archambault Rift which were thought to extend to the northeast and southeast, respectively, from a triple junction at the eastern end of the Yola Rift, does not stand up to re-examination. The "Ati Rift" was thought to follow a major linear positive gravity anomaly which had been mapped beneath the Quaternary sediments of the Chad Basin. The main gravity anomaly is separated from the Yola Rift by over 300 km and is probably due to a linear body of basic volcanic or volcano-clastic rocks associated with a suture of Pan-African age. Within the gap, between the main anomaly and the Yola Rift, there are three localised positive anomalies which relate to a gabbro of Precambrian age, a band of dense meta-sediments within the Basement Complex and an acid igneous complex of Palaeogene age. The anomaly as a whole is therefore a sequence of unrelated anomalies, none of which are due to features of Mesozoic age. The "Fort Archambault Rift" was thought to follow a major linear negative gravity anomaly which has been mapped beneath the Quaternary sediments of the Chad Basin. To a large extent the negative anomaly overlies the fosse de Baké-Birao (Baké-Birao Basin) which is itself part of a far larger structure that extends, parallel to the southern margin of the West African

  20. Regional Model Nesting Within GFS Daily Forecasts Over West Africa

    NASA Technical Reports Server (NTRS)

    Druyan, Leonard M.; Fulakeza, Matthew; Lonergan, Patrick; Worrell, Ruben

    2010-01-01

    The study uses the RM3, the regional climate model at the Center for Climate Systems Research of Columbia University and the NASA/Goddard Institute for Space Studies (CCSR/GISS). The paper evaluates 30 48-hour RM3 weather forecasts over West Africa during September 2006 made on a 0.5 grid nested within 1 Global Forecast System (GFS) global forecasts. September 2006 was the Special Observing Period #3 of the African Monsoon Multidisciplinary Analysis (AMMA). Archived GFS initial conditions and lateral boundary conditions for the simulations from the US National Weather Service, National Oceanographic and Atmospheric Administration were interpolated four times daily. Results for precipitation forecasts are validated against Tropical Rainfall Measurement Mission (TRMM) satellite estimates and data from the Famine Early Warning System (FEWS), which includes rain gauge measurements, and forecasts of circulation are compared to reanalysis 2. Performance statistics for the precipitation forecasts include bias, root-mean-square errors and spatial correlation coefficients. The nested regional model forecasts are compared to GFS forecasts to gauge whether nesting provides additional realistic information. They are also compared to RM3 simulations driven by reanalysis 2, representing high potential skill forecasts, to gauge the sensitivity of results to lateral boundary conditions. Nested RM3/GFS forecasts generate excessive moisture advection toward West Africa, which in turn causes prodigious amounts of model precipitation. This problem is corrected by empirical adjustments in the preparation of lateral boundary conditions and initial conditions. The resulting modified simulations improve on the GFS precipitation forecasts, achieving time-space correlations with TRMM of 0.77 on the first day and 0.63 on the second day. One realtime RM3/GFS precipitation forecast made at and posted by the African Centre of Meteorological Application for Development (ACMAD) in Niamey, Niger

  1. A Regional Model Study of Synoptic Features Over West Africa

    NASA Technical Reports Server (NTRS)

    Druyan, Leonard M.; Fulakeza, Matthew; Lonergan, Patrick; Saloum, Mahaman; Hansen, James E. (Technical Monitor)

    2001-01-01

    Synoptic weather features over West Africa were studied in simulations by the regional simulation model (RM) at the NASA/Goddard Institute for Space Studies. These pioneering simulations represent the beginning of an effort to adapt regional models for weather and climate prediction over West Africa. The RM uses a cartesian grid with 50 km horizontal resolution and fifteen vertical levels. An ensemble of four simulations was forced with lateral boundary conditions from ECMWF global analyses for the period 8-22 August 1988. The simulated mid-tropospheric circulation includes the skillful development and movement of several African wave disturbances. Wavelet analysis of mid-tropospheric winds detected a dominant periodicity of about 4 days and a secondary periodicity of 5-8 days. Spatial distributions of RM precipitation and precipitation time series were validated against daily rain gauge measurements and ISCCP satellite infrared cloud imagery. The time-space distribution of simulated precipitation was made more realistic by combining the ECMWR initial conditions with a 24-hr spin-up of the moisture field and also by damping high frequency gravity waves by dynamic initialization. Model precipitation "forecasts" over the Central Sahel were correlated with observations for about three days, but reinitializing with observed data on day 5 resulted in a dramatic improvement in the precipitation validation over the remaining 9 days. Results imply that information via the lateral boundary conditions is not always sufficient to minimize departures between simulated and actual precipitation patterns for more than several days. In addition, there was some evidence that the new initialization may increase the simulations' sensitivity to the quality of lateral boundary conditions.

  2. 77 FR 74265 - In the Matter of the Designation of Movement for Unity and Jihad in West Africa; Also Known as...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-13

    ... Matter of the Designation of Movement for Unity and Jihad in West Africa; Also Known as Movement for Oneness and Jihad in West Africa; Also Known as Unity Movement for Jihad in West Africa; Also Known as Jamat Tawhid Wal Jihad Fi Garbi Afriqqiya; Also Known as Tawhid Wal Jihad in West Africa; Also Known...

  3. Qur'anic and "Ajami" Literacies in Pre-Colonial West Africa

    ERIC Educational Resources Information Center

    Diallo, Ibrahima

    2012-01-01

    Traditional African literacy practices have often been ignored in the wake of European colonialism and the educational policies of colonial governments. Nonetheless, literacy had been established in parts of Africa following the introduction of Islam. This paper will examine the developments of literacy in pre-colonial West Africa. In this region,…

  4. Education and Indigenous Knowledge in Africa: Traditional Bonesetting and Orthopaedic Medicine in West Africa

    NASA Astrophysics Data System (ADS)

    Ezeanya, Chika A.

    The underlying philosophy of education in contemporary Africa has been established to be alien, and detached from the indigenous knowledge of the people. Modern day formal education in sub-Saharan Africa came about, for the most part, as a result of missionary activities and colonial efforts of Europe. The education bequeathed to Africa was, therefore, fundamentally European in paradigm and lacking in authenticity. The end of colonialism across sub-Saharan Africa did not herald any tangible transformation in the curriculum of study. Education in Africa is still dependent on foreign input for sustainability, thereby stifling research, creativity and innovation. Sustainable development is founded on indigenous knowledge. When such grassroots knowledge assumes the foundation of learning, home-grown development is easily fostered in all sectors of a national economy. In the field of medicine, indigenous knowledge of healing has been considered unscientific by western biomedical practitioners. Since the days of the missionaries, many Africans have considered indigenous medicine to be fetish; the Christian converts would not be associated with its practice and patronage. However, traditional bonesetting has been proven to be highly efficacious with little supernatural content, it continues to attract huge patronage from Africans, cutting across social and religious boundaries. This study attempts an exploration of the disconnect between indigenous knowledge, practices and learning, on the one hand, and formal education in Africa, on the other. With a focus on traditional bonesetting, the study seeks to determine why that branch of indigenous medicine attracts huge patronage, but is granted very little recognition by modern orthopaedic medical education.

  5. An interventional model to develop health professionals in West Africa.

    PubMed

    Sanou, Anselme Simeon; Awoyale, Florence Adeola; Diallo, Abdoulaye

    2014-01-01

    The health sector is characterized by a human resource base lacking in numbers, specialized skills, and management skills. West African Health Organization (WAHO) recognizes the need within the West Africa sub-region for bilingual professionals who are skilled in public health, management, leadership, and information technology to build human capacity in public health and developed the Young Professionals Internship Program (YPIP). Our study explores the evolution of the programme. YPIP program has successfully carried out its original aims and objectives to equip young professionals with basic principles of public health, management, and leadership, acquire competence in a second official language (French, English, and Portuguese), information and communication technology. Contributing factors towards this successful evaluation included positive ratings and commentary from previous interns about the relevance, usefulness, and quality of the programme, encouraging feedback from WAHO management, trainers, administrators, and intern employers on the impact of the YPIP program on young professionals, supporting evidence that demonstrates increased knowledge in professional skills and language competency.

  6. Molecular Surveillance Identifies Multiple Transmissions of Typhoid in West Africa

    PubMed Central

    Wong, Vanessa K.; Holt, Kathryn E.; Okoro, Chinyere; Baker, Stephen; Pickard, Derek J.; Marks, Florian; Page, Andrew J.; Olanipekun, Grace; Munir, Huda; Alter, Roxanne; Fey, Paul D.; Feasey, Nicholas A.; Weill, Francois-Xavier; Le Hello, Simon; Hart, Peter J.; Kariuki, Samuel; Breiman, Robert F.; Gordon, Melita A.; Heyderman, Robert S.; Jacobs, Jan; Lunguya, Octavie; Msefula, Chisomo; MacLennan, Calman A.; Keddy, Karen H.; Smith, Anthony M.; Onsare, Robert S.; De Pinna, Elizabeth; Nair, Satheesh; Amos, Ben; Dougan, Gordon; Obaro, Stephen

    2016-01-01

    Background The burden of typhoid in sub-Saharan African (SSA) countries has been difficult to estimate, in part, due to suboptimal laboratory diagnostics. However, surveillance blood cultures at two sites in Nigeria have identified typhoid associated with Salmonella enterica serovar Typhi (S. Typhi) as an important cause of bacteremia in children. Methods A total of 128 S. Typhi isolates from these studies in Nigeria were whole-genome sequenced, and the resulting data was used to place these Nigerian isolates into a worldwide context based on their phylogeny and carriage of molecular determinants of antibiotic resistance. Results Several distinct S. Typhi genotypes were identified in Nigeria that were related to other clusters of S. Typhi isolates from north, west and central regions of Africa. The rapidly expanding S. Typhi clade 4.3.1 (H58) previously associated with multiple antimicrobial resistances in Asia and in east, central and southern Africa, was not detected in this study. However, antimicrobial resistance was common amongst the Nigerian isolates and was associated with several plasmids, including the IncHI1 plasmid commonly associated with S. Typhi. Conclusions These data indicate that typhoid in Nigeria was established through multiple independent introductions into the country, with evidence of regional spread. MDR typhoid appears to be evolving independently of the haplotype H58 found in other typhoid endemic countries. This study highlights an urgent need for routine surveillance to monitor the epidemiology of typhoid and evolution of antimicrobial resistance within the bacterial population as a means to facilitate public health interventions to reduce the substantial morbidity and mortality of typhoid. PMID:27657909

  7. Sustainable Development of Research Capacity in West Africa

    NASA Astrophysics Data System (ADS)

    Liebe, J. R.; Rogmann, A.; Falk, U.; Nyarko, B. K.; Amisigo, B.; Barry, B.; Vlek, P. L.

    2010-12-01

    In West Africa, the management and efficient use of natural resources is becoming ever more important. This is largely due to steeply increasing demand through population growth and economic development, and through the effects of greater uncertainty due to climate and environmental change. Developing research capacity in these countries is an essential step in enabling them to assess their natural resources independently, and to develop national strategies and policies to manage their natural resources in the light of growing demand and increasing climatic uncertainty. The project “Sustainable Development of Research Capacity in West Africa based on the GLOWA Volta Project” (SDRC) is an 18 month project, funded by the German Ministry of Education and Research, to strengthen the research capacity in West Africa. The SDRC is based on three columns: I. knowledge transfer and strengthening of human capacity; II. strengthening of infrastructural research capacity; and III. strengthening the institutional capacity. The SDRC makes use of the wide range of research results and decision support tools developed in the GLOWA Volta Project (GVP), a nine-year, interdisciplinary research project (2000-2009) with a regional focus on the Volta Basin. The tools and models that have been transferred and trained in the framework of GVP and SDRC cover a range of topics, such as modeling the onset of the rainy season, hydrological, economic, hydro-economic modeling, GIS and Remote Sensing, and the training of database managers, to name a few. Infrastructural capacity is developed by the transfer of a micro-meteorological research network to the Meteorological Service of Burkina Faso, joint operation of a tele-transmitted hydrological gauging network with the Hydrological Service of Ghana, and the provision of hard- and software capacity to use the trained models. At the center of the SDRC effort is the strengthening of the Volta Basin Authority, a newly established river basin

  8. Guidelines for Developing an Instructional Unit on Africa: The Manding of West Africa.

    ERIC Educational Resources Information Center

    Bay, Edna G.

    The paper provides guidelines to help secondary school social studies classroom teachers develop and implement a unit on the Manding ethnic group in Africa. The objective is to illustrate how the cultural approach to Manding and to area studies in general can help students understand economic and social structures in other nations. Manding is the…

  9. Water Sources in Cape Verde and West Africa. Water in Africa.

    ERIC Educational Resources Information Center

    Maher, Robert

    The Water in Africa Project was realized over a 2-year period by a team of Peace Corps volunteers, World Wise Schools (WWS) classroom teachers, and WWS staff members. As part of an expanded, detailed design, resources were collected from over 90 volunteers serving in African countries, photos and stories were prepared, and standards-based learning…

  10. Effective elastic thickness and crustal thickness variations in west central Africa inferred from gravity data

    SciTech Connect

    Poudjom Djomani, Y.H.; Nnange, J.M.; Ebinger, C.J.

    1995-11-10

    This report uses coherence function analysis of 32,000 gravity and topography points from Cameroon west Africa to determine the relationship between the plate tectonic and flexural rigidity of the lithosphere in terms of the crusts effective elastic thickness.

  11. The Africanization of Syllabuses in Education in Anglophone and Francophone Countries of West Africa

    ERIC Educational Resources Information Center

    Kelly, Michael

    1971-01-01

    Comparison of syllabuses concludes that in West Africa English-speaking countries have made greater progress in Africanizing both the content and language of instruction than French-speaking countries. (RT)

  12. The Challenge of Drug Trafficking to Democratic Governance and Human Security in West Africa

    DTIC Science & Technology

    2013-05-01

    particularly Nigerians and Ghanaians, have been involved in the global drug trade for several decades, first with cannabis and later with heroin...global drug trade for several decades, first with cannabis and later with heroin. The problem has worsened to the point that these networks rep...independence economies of West Africa were characterized by a va- riety of illicit, shadow economies. Cannabis traffick- ing in West Africa was documented

  13. Department of Defense and Department of State Planning and Coordination Efforts in West Africa

    DTIC Science & Technology

    2016-06-10

    implement a child abuse awareness studies development program (Protecting Children Justice Ministry), and an economic development program, led by...synchronized planning efforts, in order to coordinate security and development missions in West Africa, or is there a need for DOD and DOS to commit a...full time plans and operations section to have oversight of West Africa security and development mission. There are three case studies used in this

  14. Back to Africa: Second Chances for the Children of West African Immigrants

    ERIC Educational Resources Information Center

    Bledsoe, Caroline H.; Sow, Papa

    2011-01-01

    This paper examines the phenomenon of West African parents living in Europe and North America who send their older children back home: from places of high immigrant aspiration to those of hardship and privation. Drawing on a project on West African immigration to Europe and on previous field studies in Africa, we conclude that West African…

  15. A General Survey of Religious Concepts and Art of North, East, South, and West Africa.

    ERIC Educational Resources Information Center

    Stewart, Rohn

    This paper, a summary of a multi-carousel slide presentation, reviews literature on the cultures, religions, and art of African people. Before focusing on West Africa, highlights of the lifestyles, religions, and icons of non-maskmaking cultures of North, West and South African people are presented. Clarification of West African religious concepts…

  16. A re-evaluation of the origin of hepatitis C virus genotype 2 in West Africa.

    PubMed

    Purdy, Michael A; Forbi, Joseph C; Sue, Amanda; Layden, Jennifer E; Switzer, William M; Opare-Sem, Ohene K; Phillips, Richard O; Khudyakov, Yury E

    2015-08-01

    Hepatitis C virus (HCV) is classified into seven genotypes based on genetic diversity, and most genotypes have been found in Africa. Infections with HCV genotype 2 (HCV2) are most prevalent in West Africa and it was suggested that HCV2 originated in West Africa. To better understand the evolutionary epidemiology of HCV2 in Africa, we examined new NS5B sequences of HCV2 strains obtained from Côte d'Ivoire, Ghana and Nigeria sequenced at the Centers for Disease Control and Prevention with those available from West, North and Central Africa. Bayesian phylogeographic analysis using a discrete trait model showed that Ghana was the most likely geographical region for the origin of HCV2. Spread of HCV2 from Ghana did not appear to be through diffusion to adjacent countries along the coast. Rather, it was transmitted from Ghana to many distant countries in Africa, suggesting that certain routes of geographical dissemination were historically more efficient than mere proximity and that the HCV2 epidemic history in West Africa is extremely complex.

  17. Mites associated with stored grain commodities in Benin, West Africa.

    PubMed

    Zannou, Ignace D; Adebo, Habib O; Zannou, Elisabeth; Hell, Kerstin

    2013-12-01

    After insects, mites are the major arthropod pests that inhabit stored agricultural products worldwide. To determine the acarofauna that infests cowpea, maize, paddy rice and sorghum in Benin (West Africa), surveys were conducted in some principal markets (Dantokpa, Glazoue and Parakou) of this country. A total of 555 samples of grains and debris were collected in May and September 2011. More than 56 species belonging to 24 mite families were recorded in the four products. These mite species included predators, parasites, fungivorous, phytophagous and other groups whose feeding habits are not well known. The family Cheyletidae was the most prevalent and the most diverse predatory mite family encountered, in which Cheyletus malaccensis Oudemans was the most abundant species. Several families of mite pests and mites responsible for allergies (Acaridae, Glycyphagidae, Pyroglyphidae, Pyemotidae and Saproglyphidae) were also detected. The three most dominant and frequent species were C. malaccensis, Suidasia nesbitti (Hughes) and Suidasia sp. Statistical analysis showed that densities of these three mite species were higher in Parakou than in Glazoue and Dantokpa, on one hand, and higher in debris than in grains, on the other hand. The densities of S. nesbitti and Suidasia sp. decreased significantly during the dry season, whereas C. malaccensis remained stable throughout the two samplings. Of all grains, sorghum was the least infested with mites. This study shows that in Benin mites are present in stored agricultural products to which they cause serious damage, and may cause various allergies to people.

  18. Spatial spread of the West Africa Ebola epidemic

    PubMed Central

    Pulliam, J. Tomlin; Alexander, Laura W.; Rohani, Pejman; Drake, John M.

    2016-01-01

    Controlling Ebola outbreaks and planning an effective response to future emerging diseases are enhanced by understanding the role of geography in transmission. Here we show how epidemic expansion may be predicted by evaluating the relative probability of alternative epidemic paths. We compared multiple candidate models to characterize the spatial network over which the 2013–2015 West Africa epidemic of Ebola virus spread and estimate the effects of geographical covariates on transmission during peak spread. The best model was a generalized gravity model where the probability of transmission between locations depended on distance, population density and international border closures between Guinea, Liberia and Sierra Leone and neighbouring countries. This model out-performed alternative models based on diffusive spread, the force of infection, mobility estimated from cell phone records and other hypothesized patterns of spread. These findings highlight the importance of integrated geography to epidemic expansion and may contribute to identifying both the most vulnerable unaffected areas and locations of maximum intervention value. PMID:27853607

  19. An empirical analysis of the Ebola outbreak in West Africa

    PubMed Central

    Khaleque, Abdul; Sen, Parongama

    2017-01-01

    The data for the Ebola outbreak that occurred in 2014–2016 in three countries of West Africa are analysed within a common framework. The analysis is made using the results of an agent based Susceptible-Infected-Removed (SIR) model on a Euclidean network, where nodes at a distance l are connected with probability P(l) ∝ l−δ, δ determining the range of the interaction, in addition to nearest neighbors. The cumulative (total) density of infected population here has the form , where the parameters depend on δ and the infection probability q. This form is seen to fit well with the data. Using the best fitting parameters, the time at which the peak is reached is estimated and is shown to be consistent with the data. We also show that in the Euclidean model, one can choose δ and q values which reproduce the data for the three countries qualitatively. These choices are correlated with population density, control schemes and other factors. Comparing the real data and the results from the model one can also estimate the size of the actual population susceptible to the disease. Rescaling the real data a reasonably good quantitative agreement with the simulation results is obtained. PMID:28205617

  20. An empirical analysis of the Ebola outbreak in West Africa

    NASA Astrophysics Data System (ADS)

    Khaleque, Abdul; Sen, Parongama

    2017-02-01

    The data for the Ebola outbreak that occurred in 2014–2016 in three countries of West Africa are analysed within a common framework. The analysis is made using the results of an agent based Susceptible-Infected-Removed (SIR) model on a Euclidean network, where nodes at a distance l are connected with probability P(l) ∝ l‑δ, δ determining the range of the interaction, in addition to nearest neighbors. The cumulative (total) density of infected population here has the form , where the parameters depend on δ and the infection probability q. This form is seen to fit well with the data. Using the best fitting parameters, the time at which the peak is reached is estimated and is shown to be consistent with the data. We also show that in the Euclidean model, one can choose δ and q values which reproduce the data for the three countries qualitatively. These choices are correlated with population density, control schemes and other factors. Comparing the real data and the results from the model one can also estimate the size of the actual population susceptible to the disease. Rescaling the real data a reasonably good quantitative agreement with the simulation results is obtained.

  1. An empirical analysis of the Ebola outbreak in West Africa.

    PubMed

    Khaleque, Abdul; Sen, Parongama

    2017-02-16

    The data for the Ebola outbreak that occurred in 2014-2016 in three countries of West Africa are analysed within a common framework. The analysis is made using the results of an agent based Susceptible-Infected-Removed (SIR) model on a Euclidean network, where nodes at a distance l are connected with probability P(l) ∝ l(-δ), δ determining the range of the interaction, in addition to nearest neighbors. The cumulative (total) density of infected population here has the form , where the parameters depend on δ and the infection probability q. This form is seen to fit well with the data. Using the best fitting parameters, the time at which the peak is reached is estimated and is shown to be consistent with the data. We also show that in the Euclidean model, one can choose δ and q values which reproduce the data for the three countries qualitatively. These choices are correlated with population density, control schemes and other factors. Comparing the real data and the results from the model one can also estimate the size of the actual population susceptible to the disease. Rescaling the real data a reasonably good quantitative agreement with the simulation results is obtained.

  2. The stratigraphy of the Taoudeni basin, west Africa

    SciTech Connect

    Ratcliffe, K.T.; Moody, R.T.J. )

    1993-09-01

    The Taoudeni basin is one of the major structural units of the west African craton, with an areal extent in excess of 2,000,000 km[sup 2]. Sediment thicknesses can reach over 3000 m, but have an average thickness of 1250 m. The majority of the basin-fill sediments are Precambrian to Carboniferous, with Mesozoic rocks present in the eastern margin adjacent to the Adrar des Iforas. Due to the paucity of exploration in the Taoudoni basin, there are no detailed works on source potential, maturity, or reservoir quality. However, within the sediment pile, there are excellent potential reservoirs, in the form of poorly cemented sandstones, and apparently organic-rich sediments, which may have source potential. Three major Paleozoic tectono-sedimentary units are recognized within the basin, all of which are found in the Adrar de Mauritania, which is taken as the [open quotes]type section[close quotes] for the Taoudeni basin. Unit 1 (Upper Riphean) is composed of alternating sandstones, limestones, and mudstones, which show rapid lateral thickness variations. Units 2 and 3 are far more uniform in thickness and distribution. Unit 2 (late Precambrian-Lower Ordovician) is composed of shales and sandstones with minor limestones. The base of this unit is composed of the Triad, or the Eocambrian glacial deposits that can be correlated across west Africa. Unit 3 (Upper Oedovician-Devonian) is composed of a variety of lithofacies varying from a basal glacial unit through basinal graptolitic shales into shallow marine/continental deposits. Each of these units will be discussed in detail and the petroleum potential of the constituent lithofacies considered.

  3. Declining incidence of malaria imported into the UK from West Africa

    PubMed Central

    Behrens, Ron H; Carroll, Bernadette; Smith, Valerie; Alexander, Neal

    2008-01-01

    Background Two thirds of all falciparum malaria cases reported in the United Kingdom (UK) are acquired in West Africa (WA). To ensure recommendations and guidelines for malaria prophylaxis in travellers to West Africa correlate to the risk of infection, a study was undertaken to examine recent trends and predict future patterns of imported malaria acquired by UK residents visiting West Africa and West African visitors to the UK between 1993 and 2006. Methods and Results Using passenger numbers and malaria surveillance reports, the data revealed a 2.3-fold increase in travel to West Africa with a five-fold increase in travelers visiting friends and relatives (VFR). Malaria incidence fell through the study period, the greatest decline noted in VFR with a fall from 196 cases/1,000 person-years to 52 cases/1,000 person-years, 9.8% per year p < 0.0001. The risk for travellers from the UK visiting for other reasons declined 2.7 fold, at an annual decrease of 7.0%, with the incidence in West African visitors to the UK falling by 2.3 fold, a rate of 7.9% annually. Discussion The reduction in incidence among all three groups of travellers may be explained by several factors; changing chemoprophylaxis usage and/or increased travel in urban areas where malaria risk has declined over the past decade, or widespread reduction in malaria transmission in West Africa. Conclusion With the reduction in malaria incidence seen in both visitors to and from West Africa, the most rational explanation for these findings is a fall in malaria transmission in West Africa, which may require a change in chemoprophylaxis policy for UK travelers over the next 5–10 years. PMID:19000299

  4. South Africa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image of South Africa was acquired on May 14, 2000, by NASA's Moderate-resolution Imaging Spectroradiometer, or MODIS. The image was produced using a combination of the sensor's 250-m and 500-m resolution visible wavelength bands. As part of the opening ceremony to begin the joint U.S.-South Africa SAFARI Field Experiment, NASA presented print copies of this image as GIFts to Dr. Ben Ngubane, Minister of Arts, Science and Technology, and Honorable Advocate Ngoaka Ramathlodi, Premier of the Northern Province, South Africa. The area shown in this image encompasses seven capital cities and a number of the region's distinctive geological features can be seen clearly. Toward the northern (top) central part of the image, the browns and tans comprise the Kalahari Desert of southern Botswana. The Tropic of Capricorn runs right through the heart of the Kalahari and the Botswanan capital city of Gaborone sits on the Limpopo River, southeast of the Kalahari. Along the western coastline of the continent is the country of Namibia, where the Namib Desert is framed against the sea by the Kaokoveld Mountains. The Namibian capital of Windhoek is obscured by clouds. Looking closely in the center of the image, the Orange River can be seen running from east to west, demarcating the boundary between Namibia and South Africa. On the southwestern corner of the continent is the hook-like Cape of Good Hope peninsula and Cape Town, the parliamentary capital of South Africa. Running west to east away from Cape Town are the Great Karroo Mountains. The shadow in this image conveys a sense of the very steep grade of the cliffs along the southern coast of South Africa. Port Elizabeth sits on the southeasternmost point of South Africa, and a large phytoplankton bloom can be seen in the water about 100 miles east of there. Moving northward along the east coast, the Drakensberg Mountains are visible. The two small nations of Lesotho and Swaziland are in this region, completely

  5. Climate Variability and Predictability in North West Africa

    NASA Astrophysics Data System (ADS)

    Baddour, O.; Djellouli, Y.

    2003-04-01

    North West Africa defined here as the area including Morocco, Algeria and Tunisia, it occupies a large territory in North Africa with more than 3.5 Millions KM2. The geographical contrast is very important: while most of the southern part is desert, the northern and north western part exhibits a contrasting geography including large flat areas in the western part of Morocco, northern Algeria and eastern part of Tunisia, And also the formidable Atlas mountains barrier that extends from south west of Morocco toward north west of Tunisia crossing central Morocco and north Algeria.Agriculture is one of major socio-economic activity in the region with an extensive cash-crop for exporting to Europe especially from Morocco and Tunisia. The influence of the recurring droughts during 80s and 90s was very crucial for the economic and societal aspects of the region. In Morocco, severe droughts has caused GDP fluctuation within past 20 years from 10% increase down to negative values in some particular years. Most of weather systems occurs during frontal excursion through the Atlantic and Europe bringing cold air and cloud and precipitation systems. The active precipitation period extends from October to May with almost 80% of the total rainfall. The dry season extends from June to September. Nevertheless some convective clouds develop occasionally during the dry season due to subtropical humid air mass that converge into the region and trigger the convection especially in the high area and Sahara. These less frequent precipitation systems could lead to weather hazards such as flash floods with damage to population and infrastructure. (The example of OURIKA in August 1995 in Morocco). The far south of the region experiences some tropical influence during August period especially in the south of Algeria when the ITCZ can migrate from the SAHEL area to its northernmost position in the region. Recent studies have investigated seasonal rainfall variability and prediction over

  6. Estimation of Croplands in West Africa using Global Land Cover and Land Use Datasets: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Adhikari, P.; de Beurs, K.

    2013-12-01

    Africa is vulnerable to the effects of global climate change resulting in reduced agricultural production and worsening food security. Studies show that Africa has the lowest cereal yield compared to other regions of the world. The situation is particularly dire in East, Central and West Africa. Despite their low cereal yield, the population of East, Central and West Africa has doubled between 1980 and 2007. Furthermore, West Africa has a history of severe and long droughts which have occasionally caused widespread famine. To understand how global climate change and land cover change have impacted crop production (yield) it is important to estimate croplands in the region. The objective of this study is to compare ten publicly available land cover and land use datasets, covering different time periods, to estimate croplands in West Africa. The land cover and land use data sets used cover the period from early 1990s to 2010. Preliminary results show a high variability in cropland estimates. For example, in Benin, the estimated cropland area varies from 2.5 to 21% of the total area, while it varies from 3 to 8% in Niger. Datasets with a finer resolution (≤ 1,000 m) have consistently estimated comparable cropland areas across all countries. Several categorical verification statistics such as probability of detection (POD), false alarm ratio (FAR) and critical success index are also used to analyze the correspondence between estimated and observed cropland pixels at the scales of 1 Km and 10 Km.

  7. Emission and deposition of Nitrogen compounds in West Africa

    NASA Astrophysics Data System (ADS)

    Delon, C.; Galy-Lacaux, C.; Adon, M.; Liousse, C.

    2010-12-01

    The atmospheric nitrogen budget depends on emission and deposition fluxes both as reduced and oxidized compounds. In West African ecosystems, data are scarce, and establishing a N budget is not an easy task. This work aims at linking data from diverse origins (surface, aircraft measurements, satellite data, modelling) to estimate emissions and deposition of N compounds in dry and wet savannas of West Africa, and to study their impact on atmospheric chemistry. In remote areas like in the Sahel, N oxidised compounds emissions are dominated by NO biogenic emissions from soils. N emissions from anthropogenic sources (biomass burning, domestic fires, fossil fuel) are less important, due to the low quantity of vegetation, and to the remoteness of big cities. N reduced compounds emissions are dominated by the release of NH3 from cattle dung. Biogenic NO emissions from soils have a direct impact on NOx and O3 concentration increase in the lower troposphere, as shown by results from aircraft and surface measurements, and from modelling (coupled dynamics/chemistry MESONH-C model, with on line emission derived from a neural network algorithm, where the NO flux is dependent on water field pore space, surface and deep soil temperature, sand percentage, pH, fertilization rate and wind speed), in the area of Niamey (Niger) in August 2006. In a second part of this work, estimated emissions of both oxidised and reduced N compounds are compared to estimate dry and wet deposition fluxes for the year 2006 in the Sahel region. The dry deposition flux is the product of modelled dry deposition velocity and the measured concentration. Concentrations have been measured in 3 stations located in dry savanna ecosystem) within the IDAF (IGAC/DEBITS/Africa) network, and dry deposition velocities have been modelled with the surface model ISBA. A first tentative of budget has been calculated for the year 2006, trying to integrate all potentially known sources and sinks in the region. Finally, the

  8. Spatiotemporal Analysis of the 2014 Ebola Epidemic in West Africa

    PubMed Central

    Backer, Jantien A.; Wallinga, Jacco

    2016-01-01

    In 2014–2016, Guinea, Sierra Leone and Liberia in West Africa experienced the largest and longest Ebola epidemic since the discovery of the virus in 1976. During the epidemic, incidence data were collected and published at increasing resolution. To monitor the epidemic as it spread within and between districts, we develop an analysis method that exploits the full spatiotemporal resolution of the data by combining a local model for time-varying effective reproduction numbers with a gravity-type model for spatial dispersion of the infection. We test this method in simulations and apply it to the weekly incidences of confirmed and probable cases per district up to June 2015, as reported by the World Health Organization. Our results indicate that, of the newly infected cases, only a small percentage, between 4% and 10%, migrates to another district, and a minority of these migrants, between 0% and 23%, leave their country. The epidemics in the three countries are found to be similar in estimated effective reproduction numbers, and in the probability of importing infection into a district. The countries might have played different roles in cross-border transmissions, although a sensitivity analysis suggests that this could also be related to underreporting. The spatiotemporal analysis method can exploit available longitudinal incidence data at different geographical locations to monitor local epidemics, determine the extent of spatial spread, reveal the contribution of local and imported cases, and identify sources of introductions in uninfected areas. With good quality data on incidence, this data-driven method can help to effectively control emerging infections. PMID:27930675

  9. Fluid inclusions in quartz crystals from South-West Africa

    USGS Publications Warehouse

    Kvenvolden, K.A.; Roedder, E.

    1971-01-01

    Quartz crystals from calcite veins of unknown age in Precambrian metasedimentary rocks at Geiaus No. 6 and Aukam farms in South-West Africa contain both primary and secondary inclusions filled with one or a variable combination of: organic liquid, moderately saline aqueous liquid, dark-colored solid, and vapor. Analysis of these materials by microscopy and by gas chromatography and mass spectrometry shows the presence of constituents of both low and high molecular weights. The former include CH4, C2H6, C3H8 and possibly C4H10 as well as CO, CO2, H2O, N2 and H2. High molecular weight components are dominantly n-alkanes and isoprenoid hydrocarbons. The n-alkanes range from at least n-C10 to n-C33. Concentrations of n-alkanes larger than n-C17 decrease regularly with increasing carbon number. An homologous series of isoprenoid hydrocarbons ranging from at least C14 to C20 is present in unusually high concentrations. Pristane (C19) is most abundant, and C17 isoprenoid is least abundant. The molecular composition and distribution of hydrocarbons suggest biological precursors for these components. Consideration of data provided by freezing, crushing and heating experiments suggests that the pressures at the time these in part supercritical fluids were trapped probably exceeded 30-40 atm, and the minimum trapping temperature was about 120-160??C. Both primary and secondary inclusions apparently containing only organic materials were trapped by the growth of the host quartz from aqueous solution. The data obtained neither prove nor preclude Precambrian, Paleozoic or younger sources for the organic materials. ?? 1971.

  10. Silicone wristbands detect individuals' pesticide exposures in West Africa

    PubMed Central

    Scott, Richard P.; Blaustein, Kathy L.; Halbleib, Mary L.; Sarr, Makhfousse; Jepson, Paul C.

    2016-01-01

    We detected between 2 and 10 pesticides per person with novel sampling devices worn by 35 participants who were actively engaged in farming in Diender, Senegal. Participants were recruited to wear silicone wristbands for each of two separate periods of up to 5 days. Pesticide exposure profiles were highly individualized with only limited associations with demographic data. Using a 63-pesticide dual-column gas chromatography–electron capture detector (GC-ECD) method, we detected pyrethoid insecticides most frequently, followed by organophosphate pesticides which have been linked to adverse health outcomes. This work provides the first report of individualized exposure profiles among smallholder farmers in West Africa, where logistical and practical constraints have prevented the use of more traditional approaches to exposure assessment in the past. The wristbands and associated analytical method enabled detection of a broad range of agricultural, domestic, legacy and current-use pesticides, including esfenvalerate, cypermethrin, lindane, DDT and chlorpyrifos. Participants reported the use of 13 pesticide active ingredients while wearing wristbands. All six of the pesticides that were both reportedly used and included in the analytical method were detected in at least one wristband. An additional 19 pesticide compounds were detected beyond those that were reported to be in use, highlighting the importance of measuring exposure in addition to collecting surveys and self-reported use records. The wristband method is a candidate for more widespread use in pesticide exposure and health monitoring, and in the development of evidence-based policies for human health protection in an area where food security concerns are likely to intensify agricultural production and pesticide use in the near future. PMID:27853621

  11. Revisiting evidence for sustainability of bushmeat hunting in West Africa.

    PubMed

    Waite, T A

    2007-09-01

    Bushmeat hunting, a key source of dietary protein, has been implicated as a major extinction threat to tropical vertebrate species in West Africa. Ideally, any such hunting of wild species should be done sustainably, with off-take levels low enough to ensure viability of harvested species. Recent work purports to show that a mature bushmeat market in a major city in Ghana operates sustainably after depletion of vulnerable, slow-reproducing species (Cowlishaw and others 2005). I revisit two aspects of this work. First, I retest the prediction that larger species are transported to the market from greater distances, as expected if overexploitation depletes large species close to the city. Cowlishaw and others failed to find a significantly positive relationship between species-specific body mass and distance between capture site and the market. However, my reanalysis provides evidence for a positive relationship after all, consistent with unsustainable harvesting. In particular, ungulate species were harvested significantly farther from the market than smaller-bodied rodent species. Second, I caution that just because species "persist" in the marketplace in no way implies that they can withstand hunting pressure elsewhere and so should be of little concern to conservationists. I reveal that such species, despite their high intrinsic rates of population growth, are not robust elsewhere. Several of them have disappeared from a network of protected areas in Ghana (Brashares and others 2001). I show that faster-reproducing species are not necessarily more likely to persist in protected areas. The mere presence of fast-reproducing species in a mature bushmeat market should not be construed as generalizable robustness; criteria for ecological sustainability should ensure viability; and harvested species should be robust, not highly prone to extinction, in protected areas.

  12. Land-use change and infectious disease in West Africa

    NASA Astrophysics Data System (ADS)

    Thomson, M. C.; Ericksen, P. J.; Mohamed, A. Ben; Connor, S. J.

    Land-use change has been associated with changes in the dynamics of infectious disease in West Africa. Here we describe the complex interactions of land-use change with three diseases (both vector- and non-vector-borne) of considerable public health significance in this region, namely, malaria and irrigation; epidemic meningitis and land degradation; onchocerciasis and deforestation. We highlight the confounding effect of climate variability, which acts as a driver of both land-use change and human health. We conclude, as have others, that the scale of observation always matters, and complex and dynamic feedbacks among social-ecological systems are not easily teased apart. We suggest that in order to establish the causal chain of interactions between land-use change and human health outcomes two approaches are necessary. The first is to have a thorough understanding of the aetiology of disease and the specific mechanisms by which land-use and climate variability affect the transmission of pathogens. This is achieved by focused, detailed studies encompassing a wide range of potential drivers, which are inevitably small scale and often cover short time periods. The second consists of large-scale studies of statistical associations between transmission indices or health outcomes and environmental variables stratified by known ecological or socio-economic confounders, and sufficient in size to overcome local biases in results. Such research activities need to be designed to inform each other if we are to develop predictive models for monitoring these diseases and to develop integrated programs for human health and sustainable land use.

  13. Response of the Water Cycle of West Africa and Atlantic to Radiative Forcing by Saharan Dust

    NASA Technical Reports Server (NTRS)

    Lau, K. M.; Kim, Kyu-Myong; Sud, Yogesh C.; Walker, Gregory L.

    2010-01-01

    The responses of the atmospheric water cycle and climate of West Africa and the Atlantic to radiative forcing of Saharan dust are studied using the NASA finite volume general circulation model (fvGCM), coupled to a mixed layer ocean. We find evidence in support of the "elevated heat pump" (EHP) mechanism that underlines the responses of the atmospheric water cycle to dust forcing as follow. During the boreal summer, as a result of large-scale atmospheric feed back triggered by absorbing dust aerosols, rainfall and cloudiness are enhanced over the West Africa/Easter Atlantic ITCZ, and suppressed over the West Atlantic and Caribbean. region. Shortwave radiation absorption by dust warms the atmosphere and cools the surface, while long wave has the opposite response. The elevated dust layer warms the air over Nest Africa and the eastern Atlantic. The condensation heating associated with the induced deep convection drives and maintains an anomalous large-scale east-west overturning circulation with rising motion over West Africa/eastern Atlantic, and sinking motion over the Caribbean region. The response also includes a strengthening of the West African monsoon, manifested in northward shift of the West Africa precipitation over land, increased low-level westerlies flow over West Africa at the southern edge of the dust layer, and a near surface energy fluxes, resulting in cooling of the Nest African land and the eastern Atlantic, and a warming in the West Atlantic and Caribbean. The EHP effect is most effective for moderate to highly absorbing dusts, and becomes minimized for reflecting dust with single scattering albedo at 0.95 or higher.

  14. Autosomal and mtDNA Markers Affirm the Distinctiveness of Lions in West and Central Africa.

    PubMed

    Bertola, Laura D; Tensen, Laura; van Hooft, Pim; White, Paula A; Driscoll, Carlos A; Henschel, Philipp; Caragiulo, Anthony; Dias-Freedman, Isabela; Sogbohossou, Etotépé A; Tumenta, Pricelia N; Jirmo, Tuqa H; de Snoo, Geert R; de Iongh, Hans H; Vrieling, Klaas

    2015-01-01

    The evolutionary history of a species is key for understanding the taxonomy and for the design of effective management strategies for species conservation. The knowledge about the phylogenetic position of the lion (Panthera leo) in West/Central Africa is largely based on mitochondrial markers. Previous studies using mtDNA only have shown this region to hold a distinct evolutionary lineage. In addition, anthropogenic factors have led to a strong decline in West/Central African lion numbers, thus, the conservation value of these populations is particularly high. Here, we investigate whether autosomal markers are concordant with previously described phylogeographic patterns, and confirm the unique position of the West/Central African lion. Analysis of 20 microsatellites and 1,454 bp of the mitochondrial DNA in 16 lion populations representing the entire geographic range of the species found congruence in both types of markers, identifying four clusters: 1) West/Central Africa, 2) East Africa, 3) Southern Africa and 4) India. This is not in line with the current taxonomy, as defined by the IUCN, which only recognizes an African and an Asiatic subspecies. There are no indications that genetic diversity in West/Central Africa lions is lower than in either East or Southern Africa, however, given this genetic distinction and the recent declines of lion numbers in this region, we strongly recommend prioritization of conservation projects in West/Central Africa. As the current taxonomic nomenclature does not reflect the evolutionary history of the lion, we suggest that a taxonomic revision of the lion is warranted.

  15. Autosomal and mtDNA Markers Affirm the Distinctiveness of Lions in West and Central Africa

    PubMed Central

    Bertola, Laura D.; Tensen, Laura; van Hooft, Pim; White, Paula A.; Driscoll, Carlos A.; Henschel, Philipp; Caragiulo, Anthony; Dias-Freedman, Isabela; Sogbohossou, Etotépé A.; Tumenta, Pricelia N.; Jirmo, Tuqa H.; de Snoo, Geert R.

    2015-01-01

    The evolutionary history of a species is key for understanding the taxonomy and for the design of effective management strategies for species conservation. The knowledge about the phylogenetic position of the lion (Panthera leo) in West/Central Africa is largely based on mitochondrial markers. Previous studies using mtDNA only have shown this region to hold a distinct evolutionary lineage. In addition, anthropogenic factors have led to a strong decline in West/Central African lion numbers, thus, the conservation value of these populations is particularly high. Here, we investigate whether autosomal markers are concordant with previously described phylogeographic patterns, and confirm the unique position of the West/Central African lion. Analysis of 20 microsatellites and 1,454 bp of the mitochondrial DNA in 16 lion populations representing the entire geographic range of the species found congruence in both types of markers, identifying four clusters: 1) West/Central Africa, 2) East Africa, 3) Southern Africa and 4) India. This is not in line with the current taxonomy, as defined by the IUCN, which only recognizes an African and an Asiatic subspecies. There are no indications that genetic diversity in West/Central Africa lions is lower than in either East or Southern Africa, however, given this genetic distinction and the recent declines of lion numbers in this region, we strongly recommend prioritization of conservation projects in West/Central Africa. As the current taxonomic nomenclature does not reflect the evolutionary history of the lion, we suggest that a taxonomic revision of the lion is warranted. PMID:26466139

  16. Evaluation of rainfall simulations over West Africa in dynamically downscaled CMIP5 global circulation models

    NASA Astrophysics Data System (ADS)

    Akinsanola, A. A.; Ajayi, V. O.; Adejare, A. T.; Adeyeri, O. E.; Gbode, I. E.; Ogunjobi, K. O.; Nikulin, G.; Abolude, A. T.

    2017-03-01

    This study presents evaluation of the ability of Rossby Centre Regional Climate Model (RCA4) driven by nine global circulation models (GCMs), to skilfully reproduce the key features of rainfall climatology over West Africa for the period of 1980-2005. The seasonal climatology and annual cycle of the RCA4 simulations were assessed over three homogenous subregions of West Africa (Guinea coast, Savannah, and Sahel) and evaluated using observed precipitation data from the Global Precipitation Climatology Project (GPCP). Furthermore, the model output was evaluated using a wide range of statistical measures. The interseasonal and interannual variability of the RCA4 were further assessed over the subregions and the whole of the West Africa domain. Results indicate that the RCA4 captures the spatial and interseasonal rainfall pattern adequately but exhibits a weak performance over the Guinea coast. Findings from the interannual rainfall variability indicate that the model performance is better over the larger West Africa domain than the subregions. The largest difference across the RCA4 simulated annual rainfall was found in the Sahel. Result from the Mann-Kendall test showed no significant trend for the 1980-2005 period in annual rainfall either in GPCP observation data or in the model simulations over West Africa. In many aspects, the RCA4 simulation driven by the HadGEM2-ES perform best over the region. The use of the multimodel ensemble mean has resulted to the improved representation of rainfall characteristics over the study domain.

  17. Islam in Africa

    DTIC Science & Technology

    2008-05-09

    orders as well as followers in West Africa and Sudan, and, like other orders, strives to know God through meditation and emotion. Sufis may be Sunni or...Shi’ite, and their ceremonies may involve chanting, music, dancing, and meditation . West Africa and Sudan have various Sufi orders regarded

  18. What Factors Might Have Led to the Emergence of Ebola in West Africa?

    PubMed Central

    Alexander, Kathleen A.; Sanderson, Claire E.; Marathe, Madav; Lewis, Bryan L.; Rivers, Caitlin M.; Shaman, Jeffrey; Drake, John M.; Lofgren, Eric; Dato, Virginia M.; Eisenberg, Marisa C.; Eubank, Stephen

    2015-01-01

    An Ebola outbreak of unprecedented scope emerged in West Africa in December 2013 and presently continues unabated in the countries of Guinea, Sierra Leone, and Liberia. Ebola is not new to Africa, and outbreaks have been confirmed as far back as 1976. The current West African Ebola outbreak is the largest ever recorded and differs dramatically from prior outbreaks in its duration, number of people affected, and geographic extent. The emergence of this deadly disease in West Africa invites many questions, foremost among these: why now, and why in West Africa? Here, we review the sociological, ecological, and environmental drivers that might have influenced the emergence of Ebola in this region of Africa and its spread throughout the region. Containment of the West African Ebola outbreak is the most pressing, immediate need. A comprehensive assessment of the drivers of Ebola emergence and sustained human-to-human transmission is also needed in order to prepare other countries for importation or emergence of this disease. Such assessment includes identification of country-level protocols and interagency policies for outbreak detection and rapid response, increased understanding of cultural and traditional risk factors within and between nations, delivery of culturally embedded public health education, and regional coordination and collaboration, particularly with governments and health ministries throughout Africa. Public health education is also urgently needed in countries outside of Africa in order to ensure that risk is properly understood and public concerns do not escalate unnecessarily. To prevent future outbreaks, coordinated, multiscale, early warning systems should be developed that make full use of these integrated assessments, partner with local communities in high-risk areas, and provide clearly defined response recommendations specific to the needs of each community. PMID:26042592

  19. A Multivariate Analysis of Freshwater Variability over West Africa

    NASA Astrophysics Data System (ADS)

    Andam-Akorful, S. A.; He, X.; Ferreira, V. G.; Quaye-Ballard, J. A.

    2015-12-01

    As one of the most vulnerable regions to climate change, West Africa (WA) has since the 1970s suffered sustained reduction in rainfall amounts, leading to droughts and associated negative impacts on its water resources. Although rainfall rates have been reported to have experienced a degree of recovery, dry conditions persist. Additionally, the region faces perennial flooding, thus resulting in a highly variable hydrologic regime due to the extreme climate conditions. This therefore necessitates routine monitoring of the WA's freshwater reserves and its response to climate variations at the short and long term scales to aid sustainable use and management. However, this monitoring is hampered by data deficiency issues within the region. Consequently, dynamics leading to changes in water availability over the region are not completely understood. In this work, the recent flux and state of freshwater availability over WA from 1979 to 2013 is assessed by investigating the coupled variability of GRACE-derived terrestrial water storage (TWS) and its changes (TWSC) estimates with rainfall, evapotranspiration, and land surface air temperature (LSAT), as well as, major global and regional teleconnection indices using complex principal component analysis and wavelet transforms. Since GRACE covers a relatively short period, and thereby present challenges for long to medium term analyses, Artificial Neural Network (ANN) is employed to extend the GRACE series to 1979. The results from the ANN proved to be robust upon evaluation; spatially-averaged series for major basins and sub-climatic zones, as well as, the whole of WA presented RMSE, Nash-Sutcliffe efficient, and coefficient of determination (R2) of 11.83 mm, 0.76 and 0.89 respectively. Overall, the results obtained from this study indicate that, sustained increase in water flux, in terms of TWSC, contributed to a resurgence in freshwater reserves in the 21st century over WA from the low levels in the late 20th century

  20. Groundwater Exploration for Rural Communities in Ghana, West Africa

    NASA Astrophysics Data System (ADS)

    McKay, W. A.

    2001-05-01

    Exploration for potable water in developing countries continues to be a major activity, as there are more than one billion people without access to safe drinking water. Exploration for groundwater becomes more critical in regions where groundwater movement and occurrence is controlled by secondary features such as fractures and faults. Drilling success rates in such geological settings are generally very low, but can be improved by integrating geological, hydrogeological, aerial photo interpretation with land-based geophysical technology in the selection of drilling sites. To help alleviate water supply problems in West Africa, the Conrad N. Hilton Foundation and other donors, since 1990, have funded the World Vision Ghana Rural Water Project (GRWP) to drill wells for potable water supplies in the Greater Afram Plains (GAP) of Ghana. During the first two years of the program, drilling success rates using traditional methods ranged from 35 to 80 percent, depending on the area. The average drilling success rate for the program was approximately 50 percent. In an effort to increase the efficiency of drilling operations, the Desert Research Institute evaluated and developed techniques for application to well-siting strategies in the GAP area of Ghana. A critical project element was developing technical capabilities of in-country staff to independently implement the new strategies. Simple cost-benefit relationships were then used to evaluate the economic advantages of developing water resources using advanced siting methods. The application of advanced methods in the GAP area reveal an increase of 10 to 15 percent in the success rate over traditional methods. Aerial photography has been found to be the most useful of the imagery products covering the GAP area. An effective approach to geophysical exploration for groundwater has been the combined use of EM and resistivity methods. Economic analyses showed that the use of advanced methods is cost-effective when success

  1. Risk Maps of Lassa Fever in West Africa

    PubMed Central

    Fichet-Calvet, Elisabeth; Rogers, David John

    2009-01-01

    Background Lassa fever is caused by a viral haemorrhagic arenavirus that affects two to three million people in West Africa, causing a mortality of between 5,000 and 10,000 each year. The natural reservoir of Lassa virus is the multi-mammate rat Mastomys natalensis, which lives in houses and surrounding fields. With the aim of gaining more information to control this disease, we here carry out a spatial analysis of Lassa fever data from human cases and infected rodent hosts covering the period 1965–2007. Information on contemporary environmental conditions (temperature, rainfall, vegetation) was derived from NASA Terra MODIS satellite sensor data and other sources and for elevation from the GTOPO30 surface for the region from Senegal to the Congo. All multi-temporal data were analysed using temporal Fourier techniques to generate images of means, amplitudes and phases which were used as the predictor variables in the models. In addition, meteorological rainfall data collected between 1951 and 1989 were used to generate a synoptic rainfall surface for the same region. Methodology/Principal Findings Three different analyses (models) are presented, one superimposing Lassa fever outbreaks on the mean rainfall surface (Model 1) and the other two using non-linear discriminant analytical techniques. Model 2 selected variables in a step-wise inclusive fashion, and Model 3 used an information-theoretic approach in which many different random combinations of 10 variables were fitted to the Lassa fever data. Three combinations of absence∶presence clusters were used in each of Models 2 and 3, the 2 absence∶1 presence cluster combination giving what appeared to be the best result. Model 1 showed that the recorded outbreaks of Lassa fever in human populations occurred in zones receiving between 1,500 and 3,000 mm rainfall annually. Rainfall, and to a much lesser extent temperature variables, were most strongly selected in both Models 2 and 3, and neither vegetation nor

  2. Morbidity and Mortality Due to Bordetella pertussis: A Significant Pathogen in West Africa?

    PubMed Central

    Kampmann, Beate; Mackenzie, Grant

    2016-01-01

    In the absence of specific surveillance platforms for pertussis and availability of suitable diagnostics at the hospital level, reliable data that describe morbidity and mortality from pertussis are difficult to obtain in any setting, as is the case in West Africa. Here, we summarize the available evidence of the burden of pertussis in the region, given historical data, and describe recent and ongoing epidemiological studies that offer opportunities for additional data collection. The available seroepidemiological data provide evidence of ongoing circulation of Bordetella pertussis in the region. Due to the lack of systematic and targeted surveillance with laboratory confirmation of B. pertussis infection, we cannot definitively conclude that pertussis disease is well controlled in West Africa. However, based on observations by clinicians and ongoing demographic surveillance systems that capture morbidity and mortality data in general terms, currently there is no evidence that pertussis causes a significant burden of disease in young children in West Africa. PMID:27838666

  3. Ebola in West Africa--CDC's Role in Epidemic Detection, Control, and Prevention.

    PubMed

    Frieden, Thomas R; Damon, Inger K

    2015-11-01

    Since Ebola virus disease was identified in West Africa on March 23, 2014, the Centers for Disease Control and Prevention (CDC) has undertaken the most intensive response in the agency's history; >3,000 staff have been involved, including >1,200 deployed to West Africa for >50,000 person workdays. Efforts have included supporting incident management systems in affected countries; mobilizing partners; and strengthening laboratory, epidemiology, contact investigation, health care infection control, communication, and border screening in West Africa, Nigeria, Mali, Senegal, and the United States. All efforts were undertaken as part of national and global response activities with many partner organizations. CDC was able to support community, national, and international health and public health staff to prevent an even worse event. The Ebola virus disease epidemic highlights the need to strengthen national and international systems to detect, respond to, and prevent the spread of future health threats.

  4. Modeling the impact of changes in Atlantic sea surface temperature on the climate of West Africa

    NASA Astrophysics Data System (ADS)

    Adeniyi, Mojisola O.

    2016-08-01

    This study assesses the impacts of warming/cooling of the Atlantic sea surface temperature (SST) on the climate of West Africa using Version 4.4 of Regional Climate Model (RegCM4.4) of International Center for Theoretical Physics, Trieste, Italy. The 1-2 K cooling and warming of the Atlantic SST both result in tripole temperature and precipitation change structure, having a northwest-southeast orientation over West Africa. Findings reveal that the responses of precipitation and temperature to the Atlantic SST cooling are opposite to those for the Atlantic SST warming and these responses intensify with increased warming/cooling of the Atlantic SST. The structure of the change in climate is attributed to the response of atmospheric/soil moisture gradient and orientation of orography in West Africa.

  5. Trichinella britovi etiological agent of sylvatic trichinellosis in the Republic of Guinea (West Africa) and a re-evaluation of geographical distribution for encapsulated species in Africa.

    PubMed

    Pozio, E; Pagani, P; Marucci, G; Zarlenga, D S; Hoberg, E P; De Meneghi, D; La Rosa, G; Rossi, L

    2005-08-01

    In West Africa, Trichinella infection was documented in humans and animals from Senegal in the 1960s, and the biological characters of one isolate showed a lower infectivity to domestic pigs and rodents when compared with that of a Trichinella spiralis pig isolate from Europe. To identify the Trichinella species present in West Africa, a survey was conducted in a total of 160 wild animals in the Republic of Guinea. Three Viverridae, one true civet (Viverra civetta) and two African palm civets (Nandinia binotata) from the Fouta Djallon Massif, Pilimini Subprefecture, were found positive by artificial digestion of muscle samples. Trichinella larvae from these three viverrids were identified as Trichinella britovi and no difference was detected in three examined sequences from these African isolates and the reference strain of T. britovi from Europe, indicating common ancestry, an historically continuous geographic distribution, and recent isolation for African and European populations. The detection of T. britovi in West Africa modifies our knowledge about the distribution of encapsulated species of Trichinella in Africa. Thus, Trichinella nelsoni is now considered to have a distribution limited to the Eastern part of the Afrotropical region from Kenya to South Africa. This provides a plausible explanation for the presence of Trichinella T8 in Namibia and South Africa, and further suggests that T. britovi could be the Trichinella species circulating among wild animals of Northern Africa.

  6. Exon-Enriched Libraries Reveal Large Genic Differences Between Aedes aegypti from Senegal, West Africa, and Populations Outside Africa.

    PubMed

    Dickson, Laura B; Campbell, Corey L; Juneja, Punita; Jiggins, Francis M; Sylla, Massamba; Black, William C

    2017-02-09

    Aedes aegypti is one of the most studied mosquito species, and the principal vector of several arboviruses pathogenic to humans. Recently failure to oviposit, low fecundity, and poor egg-to-adult survival were observed when Ae. aegypti from Senegal (SenAae) West Africa were crossed with Ae. aegypti (Aaa) from outside of Africa, and in SenAae intercrosses. Fluorescent in situ hybridization analyses indicated rearrangements on chromosome 1, and pericentric inversions on chromosomes 2 and 3. Herein, high throughput sequencing (HTS) of exon-enriched libraries was used to compare chromosome-wide genetic diversity among Aaa collections from rural Thailand and Mexico, a sylvatic collection from southeastern Senegal (PK10), and an urban collection from western Senegal (Kaolack). Sex-specific polymorphisms were analyzed in Thailand and PK10 to assess genetic differences between sexes. Expected heterozygosity was greatest in SenAae FST distributions of 15,735 genes among all six pairwise comparisons of the four collections indicated that Mexican and Thailand collections are genetically similar, while FST distributions between PK10 and Kaolack were distinct. All four comparisons of SenAae with Aaa indicated extreme differentiation. FST was uniform between sexes across all chromosomes in Thailand, but were different, especially on the sex autosome 1, in PK10. These patterns correlate with the reproductive isolation noted earlier. We hypothesize that cryptic Ae. aegypti taxa may exist in West Africa, and the large genic differences between Aaa and SenAae detected in the present study have accumulated over a long period following the evolution of chromosome rearrangements in allopatric populations that subsequently cause reproductive isolation when these populations became sympatric.

  7. Exon-Enriched Libraries Reveal Large Genic Differences Between Aedes aegypti from Senegal, West Africa, and Populations Outside Africa

    PubMed Central

    Dickson, Laura B.; Campbell, Corey L.; Juneja, Punita; Jiggins, Francis M.; Sylla, Massamba; Black, William C.

    2016-01-01

    Aedes aegypti is one of the most studied mosquito species, and the principal vector of several arboviruses pathogenic to humans. Recently failure to oviposit, low fecundity, and poor egg-to-adult survival were observed when Ae. aegypti from Senegal (SenAae) West Africa were crossed with Ae. aegypti (Aaa) from outside of Africa, and in SenAae intercrosses. Fluorescent in situ hybridization analyses indicated rearrangements on chromosome 1, and pericentric inversions on chromosomes 2 and 3. Herein, high throughput sequencing (HTS) of exon-enriched libraries was used to compare chromosome-wide genetic diversity among Aaa collections from rural Thailand and Mexico, a sylvatic collection from southeastern Senegal (PK10), and an urban collection from western Senegal (Kaolack). Sex-specific polymorphisms were analyzed in Thailand and PK10 to assess genetic differences between sexes. Expected heterozygosity was greatest in SenAae. FST distributions of 15,735 genes among all six pairwise comparisons of the four collections indicated that Mexican and Thailand collections are genetically similar, while FST distributions between PK10 and Kaolack were distinct. All four comparisons of SenAae with Aaa indicated extreme differentiation. FST was uniform between sexes across all chromosomes in Thailand, but were different, especially on the sex autosome 1, in PK10. These patterns correlate with the reproductive isolation noted earlier. We hypothesize that cryptic Ae. aegypti taxa may exist in West Africa, and the large genic differences between Aaa and SenAae detected in the present study have accumulated over a long period following the evolution of chromosome rearrangements in allopatric populations that subsequently cause reproductive isolation when these populations became sympatric. PMID:28007834

  8. Deconstructing "malaria": West Africa as the next front for dengue fever surveillance and control.

    PubMed

    Stoler, Justin; Al Dashti, Rawan; Anto, Francis; Fobil, Julius N; Awandare, Gordon A

    2014-06-01

    Presumptive treatment of febrile illness patients for malaria remains the norm in endemic areas of West Africa, and "malaria" remains the top source of health facility outpatient visits in many West African nations. Many other febrile illnesses, including bacterial, viral, and fungal infections, share a similar symptomatology as malaria and are routinely misdiagnosed as such; yet growing evidence suggests that much of the burden of febrile illness is often not attributable to malaria. Dengue fever is one of several viral diseases with symptoms similar to malaria, and the combination of rapid globalization, the long-standing presence of Aedes mosquitoes, case reports from travelers, and recent seroprevalence surveys all implicate West Africa as an emerging front for dengue surveillance and control. This paper integrates recent vector ecology, public health, and clinical medicine literature about dengue in West Africa across community, regional, and global geographic scales. We present a holistic argument for greater attention to dengue fever surveillance in West Africa and renew the call for improving differential diagnosis of febrile illness patients in the region.

  9. West Nile Disease Epidemiology in North-West Africa: Bibliographical Review.

    PubMed

    Benjelloun, A; El Harrak, M; Belkadi, B

    2016-12-01

    West Nile fever (WNF) or West Nile disease (WND) is a mosquito-borne viral disease that can affect birds, humans and horses. West Nile virus (WNV) is a member of the genus Flavivirus in the family Flaviviridae. WNV is maintained in a mosquito-bird-mosquito transmission cycle, whereas humans and horses are considered dead-end hosts. In human and horses, symptoms range from unapparent infection to mild febrile illness, meningitis, encephalitis or death. WNV has a wide geographical range that includes portions of Europe, Asia, Africa, Australia (Kunjin virus), and in North, Central and South America. Migratory birds are thought to be primarily responsible for virus dispersal, including reintroduction of WNV from endemic areas into regions that experience sporadic outbreaks (Fields Virology, 2001, Lippincott Williams and Wilkins, Philadelphia, Pennsylvania, USA, 1043-1125). The occurrence of disease in humans and animals along with birds and mosquitoes surveillance for WNV activity demonstrates that the virus range has dramatically expanded including North, Central and South America as well as Europe and countries facing the Mediterranean Basin. WND infection in humans has been reported in Morocco in 1996 (Virologie, 1, 1997, 248), in Tunisia in 2007 (Ann. N. Y. Acad., 951, 2001, 117) (Med. Trop., 61, 2001, 487) and 2003 (Epidémiologie de la fièvre West Nile, 2012, Thèse de doctorat, Université Montpellier II, Sciences et techniques du Langueduc, Montpellier, France), and in Algeria in 1994 (Rev. Sci. Tech., 31, 2012, 829). Outbreaks of equine encephalitis have been also reported in Morocco in 1996 (Bull. OIE, 11, 1996, 867), in 2003 (Emerg. Infect. Dis., 11, 2005, 306) and in 2010 (World Animal Health Information Database. WAHID, 2010). Serological evidence of WNV has been demonstrated in the three countries in many species. The aim of this review was to assess the epidemiological situation of WND in north-west Africa comprising Morocco, Algeria and Tunisia, with

  10. Infection Prevention and Control for Ebola in Health Care Settings - West Africa and United States.

    PubMed

    Hageman, Jeffrey C; Hazim, Carmen; Wilson, Katie; Malpiedi, Paul; Gupta, Neil; Bennett, Sarah; Kolwaite, Amy; Tumpey, Abbigail; Brinsley-Rainisch, Kristin; Christensen, Bryan; Gould, Carolyn; Fisher, Angela; Jhung, Michael; Hamilton, Douglas; Moran, Kerri; Delaney, Lisa; Dowell, Chad; Bell, Michael; Srinivasan, Arjun; Schaefer, Melissa; Fagan, Ryan; Adrien, Nedghie; Chea, Nora; Park, Benjamin J

    2016-07-08

    The 2014-2016 Ebola virus disease (Ebola) epidemic in West Africa underscores the need for health care infection prevention and control (IPC) practices to be implemented properly and consistently to interrupt transmission of pathogens in health care settings to patients and health care workers. Training and assessing IPC practices in general health care facilities not designated as Ebola treatment units or centers became a priority for CDC as the number of Ebola virus transmissions among health care workers in West Africa began to affect the West African health care system and increasingly more persons became infected. CDC and partners developed policies, procedures, and training materials tailored to the affected countries. Safety training courses were also provided to U.S. health care workers intending to work with Ebola patients in West Africa. As the Ebola epidemic continued in West Africa, the possibility that patients with Ebola could be identified and treated in the United States became more realistic. In response, CDC, other federal components (e.g., Office of the Assistant Secretary for Preparedness and Response) and public health partners focused on health care worker training and preparedness for U.S. health care facilities. CDC used the input from these partners to develop guidelines on IPC for hospitalized patients with known or suspected Ebola, which was updated based on feedback from partners who provided care for Ebola patients in the United States. Strengthening and sustaining IPC helps health care systems be better prepared to prevent and respond to current and future infectious disease threats.The activities summarized in this report would not have been possible without collaboration with many U.S. and international partners (http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/partners.html).

  11. West Africa [in "State of the Climate in 2014"

    SciTech Connect

    Hagos, Samson M.; Ijampy, James A.; Sima, Fatou; Francis, Sabastine

    2015-08-06

    This chapter provides summaries of the 2014 temperature and precipitation conditions across seven broad regions: North America, Central America and the Caribbean, South America, Africa, Europe, Asia, and Oceania. In most cases, summaries of notable weather events are also included. Local scientists provided the annual summary for their respective regions and, unless otherwise noted, the source of the data used is typically the agency affiliated with the authors. Please note that different nations, even within the same section, may use unique periods to define their normals. Section introductions will typically define the prevailing practices for that section, and exceptions will be noted within the text. In a similar way, many contributing authors use languages other than English as their primary professional language. To minimize additional loss of fidelity through re-interpretation after translation, editors have been conservative and careful to preserve the voice of the author. In some cases, this may result in abrupt transitions in style from section to section.

  12. Simulating malaria transmission in the current and future climate of West Africa

    NASA Astrophysics Data System (ADS)

    Yamana, T. K.; Bomblies, A.; Eltahir, E. A. B.

    2015-12-01

    Malaria transmission in West Africa is closely tied to climate, as rain fed water pools provide breeding habitat for the anopheles mosquito vector, and temperature affects the mosquito's ability to spread disease. We present results of a highly detailed, spatially explicit mechanistic modelling study exploring the relationships between the environment and malaria in the current and future climate of West Africa. A mechanistic model of human immunity was incorporated into an existing agent-based model of malaria transmission, allowing us to move beyond entomological measures such as mosquito density and vectorial capacity to analyzing the prevalence of the malaria parasite within human populations. The result is a novel modelling tool that mechanistically simulates all of the key processes linking environment to malaria transmission. Simulations were conducted across climate zones in West Africa, linking temperature and rainfall to entomological and epidemiological variables with a focus on nonlinearities due to threshold effects and interannual variability. Comparisons to observations from the region confirmed that the model provides a reasonable representation of the entomological and epidemiological conditions in this region. We used the predictions of future climate from the most credible CMIP5 climate models to predict the change in frequency and severity of malaria epidemics in West Africa as a result of climate change.

  13. Policy Review on Adult Learning: The Adult Non-Formal Education Policy of Mali, West Africa

    ERIC Educational Resources Information Center

    Gadio, Moussa

    2011-01-01

    This article focuses on the issue of policy development for adult learning in Mali, West Africa. On January 2007, the Malian government adopted the "Adult Non-formal Education Policy Document," which was intended to regulate the adult learning sector and federate the actions of policy makers, adult education providers, and adult…

  14. Lassa fever in West Africa: evidence for an expanded region of endemicity.

    PubMed

    Sogoba, N; Feldmann, H; Safronetz, D

    2012-09-01

    Lassa virus (LASV) is endemic in Sierra Leone, Guinea and Liberia (known as the Mano River region) and Nigeria and Lassa fever cases from these countries are being reported annually. Recent investigations have found evidence for an expanded endemicity zone between the two known Lassa endemic regions indicating that LASV is more widely distributed throughout the Tropical Wooded Savanna ecozone in West Africa.

  15. Cultural Issues in Secondary Education Development in West Africa: Away from Colonial Survivals, towards Neocolonial Influences.

    ERIC Educational Resources Information Center

    Quist, Hubert O.

    2001-01-01

    In urban Ghana and Cote d'Ivoire (Ivory Coast), cultural factors arising from West Africa's "triple cultural heritage" (African, Euro-Christian, and Islamic) and globalization place considerable strains on secondary education and have implications for postcolonial nation-building and development. Surveys of 200 secondary students in the…

  16. Adolescent and Adult Reasoning about Gender Roles and Fairness in Benin, West Africa

    ERIC Educational Resources Information Center

    Conry-Murray, Clare

    2009-01-01

    This study examined reasoning about gender roles in a traditional society in Benin, West Africa. Ninety-seven male and female adolescents and adults evaluated conflicts between a husband and a wife over gender norms to determine whether gender norms, are judged to be moral or conventional. Although most attributed decision-making power to the…

  17. Traditional Apprenticeship in West Africa: Recent Evidence and Policy Options. Discussion Paper No. 34.

    ERIC Educational Resources Information Center

    Fluitman, Fred

    Apprenticeship is the main avenue to self-employment in micro-enterprises and thus a cornerstone of informal sector development in West Africa. Survey results for Ibadan, Lome, Dakar, Niamey, and other cities demonstrate that apprenticeship as practiced by informal sector artisans is often very similar from one country to the next. Dropout rates…

  18. Education and Economics in West Africa: From Unwritten Languages to the Internet

    ERIC Educational Resources Information Center

    Alibrandi, Marsha; Bull, Prince Hycy

    2005-01-01

    Global distribution of West African goods--coffee, chocolate, gold, diamonds (and at one time, ivory)--has linked this region to the outside world for centuries, yet its development remains slow. Not simply the ancestral home of humankind, Africa's western legacies include colonization, partition, and loss of untold millions to slavery and wars of…

  19. School Leadership in West Africa: Findings from a Systematic Literature Review

    ERIC Educational Resources Information Center

    Bush, Tony; Glover, Derek

    2016-01-01

    The literature shows that leadership is the second most important factor influencing school and learner outcomes, including levels of literacy and numeracy, school leaving examination results, and progression to secondary and higher education. This article focuses on school leadership in West Africa, drawing on a systematic review of the academic…

  20. The Association between Bullying and Psychological Health among Senior High School Students in Ghana, West Africa

    ERIC Educational Resources Information Center

    Owusu, Andrew; Hart, Peter; Oliver, Brittney; Kang, Minsoo

    2011-01-01

    Background: School-based bullying, a global challenge, negatively impacts the health and development of both victims and perpetrators. This study examined the relationship between bullying victimization and selected psychological variables among senior high school (SHS) students in Ghana, West Africa. Methods: This study utilized data from the…

  1. Study Abroad in West Africa: An Interdisciplinary Program of International Education

    ERIC Educational Resources Information Center

    Lowe, Tony B.; Dozier, Cheryl D.; Hunt-Hurst, Patricia; Smith, Bettye P.

    2008-01-01

    This article describes development of an interdisciplinary study abroad program to West Africa at the University of Georgia to help students gain a global perspective. The program is interdisciplinary with several disciplines including social work, clothing and textile, history, and teacher education. This article discusses/highlights a need for a…

  2. Stochastic rainfall modeling in West Africa: Parsimonious approaches for domestic rainwater harvesting assessment

    NASA Astrophysics Data System (ADS)

    Cowden, Joshua R.; Watkins, David W., Jr.; Mihelcic, James R.

    2008-10-01

    SummarySeveral parsimonious stochastic rainfall models are developed and compared for application to domestic rainwater harvesting (DRWH) assessment in West Africa. Worldwide, improved water access rates are lowest for Sub-Saharan Africa, including the West African region, and these low rates have important implications on the health and economy of the region. Domestic rainwater harvesting (DRWH) is proposed as a potential mechanism for water supply enhancement, especially for the poor urban households in the region, which is essential for development planning and poverty alleviation initiatives. The stochastic rainfall models examined are Markov models and LARS-WG, selected due to availability and ease of use for water planners in the developing world. A first-order Markov occurrence model with a mixed exponential amount model is selected as the best option for unconditioned Markov models. However, there is no clear advantage in selecting Markov models over the LARS-WG model for DRWH in West Africa, with each model having distinct strengths and weaknesses. A multi-model approach is used in assessing DRWH in the region to illustrate the variability associated with the rainfall models. It is clear DRWH can be successfully used as a water enhancement mechanism in West Africa for certain times of the year. A 200 L drum storage capacity could potentially optimize these simple, small roof area systems for many locations in the region.

  3. The Contribution of the Society of the Holy Child Jesus to Catholic Education in West Africa

    ERIC Educational Resources Information Center

    Aidoo, Philomena

    2016-01-01

    This article discusses the extent to which the charism and the philosophy of education of Venerable Cornelia Connelly founder of the Society of the Holy Child Jesus are being maintained in the twenty-first century in West Africa (Nigeria and Ghana). Using data gathered from Sisters and former students of Holy Child schools as evidence it seeks to…

  4. Rural Development in Africa: A Bibliography (Part II: North, South, West). Training & Methods Series, Number 17.

    ERIC Educational Resources Information Center

    Wisconsin Univ., Madison. Land Tenure Center.

    Compiled in December 1971, this bibliography lists approximately 940 books, journals, periodicals, and unpublished mimeographs dealing with rural development in north, west, and southern Africa. All materials are dated between 1953 and 1971. Entries are listed by country under the following headings: agriculture, economic affairs, social affairs,…

  5. Vulnerability to changes in malaria transmission due to climate change in West Africa

    NASA Astrophysics Data System (ADS)

    Yamana, T. K.; Eltahir, E. A.

    2012-12-01

    Malaria transmission in West Africa is strongly tied to climate; temperature affects the development rate of the malaria parasite, as well as the survival of the mosquitoes that transmit the disease, and rainfall is tied to mosquito abundance, as the vector lays its eggs in rain-fed water pools. As a result, the environmental suitability for malaria transmission in this region is expected to change as temperatures rise and rainfall patterns are altered. The vulnerability to changes in transmission varies throughout West Africa. Areas where malaria prevalence is already very high will be less sensitive to changes in transmission. Increases in environmental suitability for malaria transmission in the most arid regions may still be insufficient to allow sustained transmission. However, areas were malaria transmission currently occurs at low levels are expected to be the most sensitive to changes in environmental suitability for transmission. Here, we use data on current environment and malaria transmission rates to highlight areas in West Africa that we expect to be most vulnerable to an increase in malaria under certain climate conditions. We then analyze climate predictions from global climate models in vulnerable areas, and make predictions for the expected change in environmental suitability for malaria transmission using the Hydrology, Entomology and Malaria Transmission Simulator (HYDREMATS), a mechanistic model developed to simulate village-scale response of malaria transmission to environmental variables in West Africa.

  6. Mean state and kinematic properties of mesoscale convective systems over West Africa

    NASA Astrophysics Data System (ADS)

    Ogungbenro, Stephen B.; Ajayi, V. O.; Adefolalu, D. O.

    2016-04-01

    A 17-year (1984 to 2000) dataset of brightness temperature (T b) was employed to study the spatial and temporal scales of mesoscale convective systems (MCS) over West Africa. The kinematic properties of MCS were tested using wind products. A threshold brightness temperature (T b) of ≤213 K and spatial coverage specifications of more than 5000 km2 were used as two set criteria for initiating MCS tracking. MCS occurrences vary in seasons and locations over West Africa, and their activities vary with different weather zones. They can appear at any time of the day, but this study revealed a significant preference for early morning hours and night hours over continental West Africa. The well-organized systems occur between July and September in the Sahel, and between May and September in the Savanna band. MCS activities in the Gulf of Guinea peak between March and April, while the Savanna and Sahel zones peak between June and August. The produced annual atlas gives a spatial account of areas of MCS dominance in West Africa. The presence of African Easterly Jet (AEJ) and Tropical Easterly Jet (TEJ), and deep monsoon depth all characterize an environment where MCS thrive. Kinematic study of a typical MCS reveals that the monsoon depth increases at the passage of MCS, with cyclonic vorticity dominating from the surface to 300 hpa while anticyclonic vorticity was observed around 200 hpa, and this confirms the importance of low level convergence and upper level divergence as the major requirements for storm mobilization and maintenance.

  7. Southern Africa

    Atmospheric Science Data Center

    2013-04-16

    ... tip of South Africa is at the bottom of the image, and Zambia is at the top. Distinctive features about a third of the way from the ... MISR Team. Aug 25, 2000 - South Africa to Zambia including the Okavango Delta. project:  MISR ...

  8. Lessons of Risk Communication and Health Promotion - West Africa and United States.

    PubMed

    Bedrosian, Sara R; Young, Cathy E; Smith, Laura A; Cox, Joanne D; Manning, Craig; Pechta, Laura; Telfer, Jana L; Gaines-McCollom, Molly; Harben, Kathy; Holmes, Wendy; Lubell, Keri M; McQuiston, Jennifer H; Nordlund, Kristen; O'Connor, John; Reynolds, Barbara S; Schindelar, Jessica A; Shelley, Gene; Daniel, Katherine Lyon

    2016-07-08

    During the response to the 2014-2016 Ebola virus disease (Ebola) epidemic in West Africa, CDC addressed the disease on two fronts: in the epidemic epicenter of West Africa and at home in the United States. Different needs drove the demand for information in these two regions. The severity of the epidemic was reflected not only in lives lost but also in the amount of fear, misinformation, and stigma that it generated worldwide. CDC helped increase awareness, promoted actions to stop the spread of Ebola, and coordinated CDC communication efforts with multiple international and domestic partners. CDC, with input from partners, vastly increased the number of Ebola communication materials for groups with different needs, levels of health literacy, and cultural preferences. CDC deployed health communicators to West Africa to support ministries of health in developing and disseminating clear, science-based messages and promoting science-based behavioral interventions. Partnerships in West Africa with local radio, television, and cell phone businesses made possible the dissemination of messages appropriate for maximum effect. CDC and its partners communicated evolving science and risk in a culturally appropriate way to motivate persons to adapt their behavior and prevent infection with and spread of Ebola virus. Acknowledging what is and is not known is key to effective risk communication, and CDC worked with partners to integrate health promotion and behavioral and cultural knowledge into the response to increase awareness of the actual risk for Ebola and to promote protective actions and specific steps to stop its spread. The activities summarized in this report would not have been possible without collaboration with many U.S. and international partners (http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/partners.html).

  9. [Population growth and global warming: impacts on tsetse and trypanosomoses in West Africa].

    PubMed

    Courtin, F; Sidibé, I; Rouamba, J; Jamonneau, V; Gouro, A; Solano, P

    2009-03-01

    Demographic evolution, climatic change and economical development that happened in West Africa during the XXth century had a lot of consequences on human settlement and landscape. These changes have in turn an impact on the pathogenic system of human and animal trypanosomoses. Since last century, the northern tsetse distribution limit has shifted towards the south, probably due to a decrease in rainfall combined to the impact of human pressure. Sleeping sickness (SS) foci have also shifted from the savannah areas (where there is no more SS) to the forest and mangrove areas of West Africa, but animal trypanosomoses are still present in savannah. We show a decrease of tsetse of the morsitans group as a result of an increase of human densities. On the opposite, tsetse species like Glossina palpalis adapt to high human densities and are found in the biggest urban centres of West Africa. There is a need to promote multidisciplinary studies on this demographic-climatic-vector borne disease topic, especially in Africa to be able to define future areas of presence/absence of these diseases in order to help continental plans of control that have recently begun.

  10. Assessment of future streamflow changes in major rivers of West Africa

    NASA Astrophysics Data System (ADS)

    Roudier, Philippe; Rojas, Rodrigo; Bisselink, Bernard; Feyen, Luc

    2013-04-01

    Although being one of the most vulnerable regions of the world to climate change, impact studies in West Africa, especially concerning water resources, are still scarce compared to other regions such as Europe, North-America or Asia. Therefore, we investigate in this study how climate change may affect the main rivers of West Africa (Niger, Volta, Senegal) using the global LISFLOOD model. This hydrological rainfall-runoff model, extensively used for pan-European assessments, has been recently set up and calibrated for Africa, allowing such impact analysis. Here, LISFLOOD is set up on a 0.1*0.1 degree grid for the period 1991-2050. Quantifying the uncertainty in climate impact studies is now a fundamental task, especially in West Africa where the agreement among rainfall projections is low. We therefore employ an ensemble of climate experiments originating from 8 different GCM/RCM combinations obtained from the EU FP6 ENSEMBLES project (SRES A1B scenario). Prior to forcing LISFLOOD, bias in the precipitation and temperature fields (Tmin, Tavg and Tmax) is removed with a quantile mapping method using as target the WATCH Forcing Data. In order to take into account the high population growth in West Africa we also account for projected changes in water use. Results first focus on changes in average streamflow conditions and how these changes affect water availability, expressed by the Water Exploitation Index. Second, and as underlined by the recent SREX IPCC report (2012), we show the impacts on extreme events (droughts and floods) using relevant indices such as the 100-year return period flood.

  11. Multimodel ensemble simulations of present and future climates over West Africa: Impacts of vegetation dynamics

    NASA Astrophysics Data System (ADS)

    Erfanian, Amir; Wang, Guiling; Yu, Miao; Anyah, Richard

    2016-09-01

    In this study, we take an ensemble modeling approach using the regional climate model RegCM4.3.4-CLM-CN-DV (RCM) to study the impact of including vegetation dynamics on model performance in simulating present-day climate and on future climate projections over West Africa. The ensemble consists of four global climate models (GCMs) as lateral boundary conditions for the RCM, and simulations with both static and dynamic vegetation are conducted. The results demonstrate substantial sensitivity of the simulated precipitation, evapotranspiration, and soil moisture to vegetation representation. Although including dynamic vegetation in the model eliminates potential inconsistencies between surface climate and the bioclimatic requirements of the prescribed vegetation, it enhances model biases causing climate drift. For present-day climate, the ensemble average generally outperforms individual members due to cancelation of model biases. For future changes, although the original GCMs project contradicting future rainfall trends over West Africa, the RCMs-produced trends are generally consistent. The multimodel ensemble projects significant decreases of rainfall over a major portion of West Africa and significant increases over eastern Sahel and East Africa. Projected future changes of evapotranspiration and soil moisture are consistent with those of precipitation, with significant decreases (increases) for western (eastern) Sahel. Accounting for vegetation-climate interactions has localized but significant impacts on projected future changes of precipitation, with a wet signal over a belt of projected increase of woody vegetation cover; the impact on the projected future changes of evapotranspiration and soil moisture over west and central Africa is much more profound.

  12. Geology of the Douala basin, offshore Cameroon, West Africa

    SciTech Connect

    Pauken, R.J.; Thompson, J.M.; Schumann, J.R. ); Cooke, J.C. )

    1991-03-01

    The Douala basin is predominantly an offshore basin extending from the Cameroon volcanic line in the north to the Corisco arch in the south near the Equatorial Guinea-Gabon border. The basin lies wholly within the territorial borders of Cameroon and Equatorial Guinea. The Douala basin is one of a series of divergent margin basins occurring along the southwest African coastline resulting from the rifting of Africa from South America. Continental rifting in the Doula basin was initiated at least by Aptian-Albian time and possibly as early as Jurassic. The rift stage persisted until Albian time when the onset of drifting occurred. The sedimentary section in the basin has a maximum thickness of 8-10 km, based on exploration drilling and gravity and magnetics modeling. The synrift section consists of Aptian-Albian sands and shales, deposited primarily as submarine fans, fan-deltas, and turbidite deposits. These are overlain by salt, thought to be equivalent to the Ezagna salt of Aptian age in the Gabon basin to the south. The synrift section is separated from the overlying postrift shale sequence of Late Cretaceous and Tertiary age by a major late Albian unconformity. The Douala basin has been explored for hydrocarbons intermittently over the last 25 years. Results show a distinct tendency for gas-proneness. The largest field recorded to date is the Sanaga Sud gas field, discovered in 1979, offshore, near the coastal city of Kribi.

  13. Meteorological causes of Harmattan dust in West Africa

    NASA Astrophysics Data System (ADS)

    Schwanghart, Wolfgang; Schütt, Brigitta

    2008-03-01

    We investigated the temporal dynamics of dust entrainment in the Bodélé Depression, Central Sahara, to better understand the intra-annual variability of aerosol emission in the world's largest dust source. The linkages between dust entrainment and large-scale meteorological factors were examined by correlating several meteorological variables in the Mediterranean and Africa north of the equator with the aerosol concentrations in the Bodélé Depression separately for winter and summer. The methodological tools applied are NCEP/NCAR reanalysis data and the aerosol index of the Total Ozone Mapping Spectrometer (TOMS-AI), available for 15 years from 1978 to 1993. We found that dust mobilisation during the Harmattan season is highly dependent on air pressure variability in the Mediterranean area. High pressure to the north of the Bodélé intensifies the NE trade winds, leading to an increased entrainment of dust in the Bodélé Depression. In summer, dust mobilization cannot be explained by the large scale meteorological conditions. This highlights the importance of local to regional wind systems linked to the northernmost position of the intertropical convection zone (ITCZ) during this time.

  14. Atmospheric nutrient deposition to the west coast of South Africa

    NASA Astrophysics Data System (ADS)

    Nyaga, Justine M.; Cramer, Michael D.; Neff, Jason C.

    2013-12-01

    Atmospheric deposition is an important source of nutrients to many ecosystems, but is of particular importance to plant nutrition in areas where nutrients are scarce. Nutrient containing aerosols enter the atmosphere through industrial and agricultural activities, wildfires, and the production of terrigenous and marine aerosols. In this study, we collected bulk rain precipitation along the Atlantic coast of South Africa in a coastal “strandveld” vegetation region. This region is relatively remote from significant anthropogenic influences and is downwind of a highly productive and stormy portion of the Atlantic. Samples were collected over 12 months at sites along a 17 km downwind transect from the shoreline and analyzed for N, P, Na, Ca, Mg and K. Annual total N and total P fluxes of 4.8 kg ha-1 yr-1 and 0.16 kg ha-1 yr-1 are low compared to global averages. In contrast, fluxes of Na were 88.7 kg ha-1 yr-1, 16.2 kg ha-1 yr-1 for Ca, 12.1 kg ha-1 yr-1 for Mg and 5.2 kg ha-1 yr-1 for K; rates that are higher than most other measurements elsewhere in the world. Dissolved organic N represented ca. 71% of the N flux while 43% of the P flux was in the form of soluble reactive P (SRP). These results combined with the high fluxes of Na and Mg strongly suggest that marine aerosols are important contributors to nutrient deposition at this site.

  15. Onchocerciasis: a major social problem in West Africa.

    PubMed

    Quarcoopome, C O

    1983-01-01

    Onchocerciasis is one of the most serious blinding diseases in the world, affecting between 20 and 25 million people, of whom 200-500 thousand are blind. In Africa more than half of the countries on the continent are affected, the basin of the Volta river containing one of the largest endemic areas. In this area the unique Onchocerciasis Control Program (OCP) is being undertaken, involving Benin, Ghana, Ivory Coast, Mali, Niger, Togo and Upper Volta. In this region, surveys have shown that 14.78% of the population have microfilariae in their skin biopsies, while in hyperendemic villages the figure rises to 75.2%. In such a village the prevalence of blindness rises steeply with age, from 0% under age 20, to over 40% in the over 50 age group. Various environmental factors relevant to the prevalence and incidence of systemic and ocular onchocerciasis are discussed, and pharmacologic treatment modalities are described. Prevention activities, centred around vector control by insecticides, have been dramatically effective.

  16. Influence of Madden-Julian Oscillation (MJO) on Rainfall Variability over West Africa at Intraseasonal Timescale

    NASA Astrophysics Data System (ADS)

    Niang, C.

    2015-12-01

    Intraseasonal variability of rainfall over West Africa plays a significant role in the economy of the region and is highly linked to agriculture and water resources. This research study aims to investigate the relationship between Madden Julian Oscillation (MJO) and rainfall over West Africa during the boreal summer in the the state-of-the-art Atmospheric Model Intercomparison Project (AMIP) type simulations performed by Atmosphere General Circulation Models (GCMs) forced with prescribed Sea Surface Temperature (SST). It aims to determine the impact of MJO on rainfall and convection over West Africa and identify the dynamical processes which are involved in the state-of-the-art climate simulations. The simulations show in general good skills in capturing its main characteristics as well as its influence on rainfall over West Africa. On the global scale, most models simulated an eastward spatio-temporal propagation of enhanced and suppressed convection similar to the observed. However, over West Africa the MJO signal is weak in few of the models although there is a good coherence in the eastward propagation. The influence on rainfall is well captured in both Sahel and Guinea regions thereby adequately producing the transition between positive and negative rainfall anomalies through the different phases as seen in the observation. Furthermore, the results show that strong active convective phase is clearly associated with the African Easterly Jet (AEJ) but the weak convective phase is associated with a much weaker AEJ particularly over coastal Ghana. In assessing the mechanisms which are involved in the above impacts the convectively equatorial coupled waves (CCEW) are analysed separately. The analysis of the longitudinal propagation of zonal wind at 850hPa and outgoing longwave radiation (OLR) shows that the CCEW are very weak and their extention are very limited beyong West African region. It was found that the westward coupled equatorial Rossby waves are needed to

  17. Geology and total petroleum systems of the West-Central Coastal province (7203), West Africa

    USGS Publications Warehouse

    Brownfield, Michael E.; Charpentier, Ronald R.

    2006-01-01

    The West-Central Coastal Province of the Sub-Saharan Africa Region consists of the coastal and offshore areas of Cameroon, Equatorial Guinea, Gabon, Democratic Republic of the Congo, Republic of the Congo, Angola (including the disputed Cabinda Province), and Namibia. The area stretches from the east edge of the Niger Delta south to the Walvis Ridge. The West-Central Coastal Province includes the Douala, Kribi-Campo, Rio Muni, Gabon, Congo, Kwanza, Benguela, and Namibe Basins, which together form the Aptian salt basin of equatorial west Africa. The area has had significant exploration for petroleum; more than 295 oil fields have been discovered since 1954. Since 1995, several giant oil fields have been discovered, especially in the deep-water area of the Congo Basin. Although many total petroleum systems may exist in the West-Central Coastal Province, only four major total petroleum systems have been defined. The area of the province north of the Congo Basin contains two total petroleum systems: the Melania-Gamba Total Petroleum System, consisting of Lower Cretaceous source and reservoir rocks, and the Azile-Senonian Total Petroleum System, consisting of Albian to Turonian source rocks and Cretaceous reservoir rocks. Two assessment units are defined in the West-Central Coastal Province north of the Congo Basin: the Gabon Subsalt and the Gabon Suprasalt Assessment Units. The Congo Basin contains the Congo Delta Composite Total Petroleum System, consisting of Lower Cretaceous to Tertiary source and reservoir rocks. The Central Congo Delta and Carbonate Platform and the Central Congo Turbidites Assessment Units are defined in the Congo Delta Composite Total Petroleum System. The area south of the Congo Basin contains the Cuanza Composite Total Petroleum System, consisting of Lower Cretaceous to Tertiary source and reservoir rocks. The Cuanza-Namibe Assessment Unit is defined in the Cuanza Composite Total Petroleum System. The U.S. Geological Survey (USGS) assessed the

  18. Response of the water cycle of West Africa and Atlantic to radiative forcing by Saharan dust (Invited)

    NASA Astrophysics Data System (ADS)

    Lau, W. K.; Kim, K.

    2010-12-01

    The responses of the atmospheric water cycle and climate of West Africa and the Atlantic toradiative forcing of Saharan dust are studied using the NASA finite volume general circulation model (fvGCM), coupled to a mixed layer ocean. We find evidence in support of the “elevated heat pump” (EHP) mechanism that underlines the responses of the atmospheric water cycle to dust forcing as follow. During the boreal summer, as a result of large-scale atmospheric feedback triggered by absorbing dust aerosols, rainfall and cloudiness are enhanced over the West Africa/Eastern Atlantic ITCZ, and suppressed over the West Atlantic and Caribbean region. Shortwave radiation absorption by dust warms the atmosphere and cools the surface, while longwave has the opposite response. The elevated dust layer warms the air over West Africa and the eastern Atlantic. As the warm air rises, it spawns a large-scale onshore flow carrying the moist air from the eastern Atlantic and the Gulf of Guinea. The onshore flow in turn enhances the deep convection over West Africa land, and the eastern Atlantic. The condensation heating associated with the induced deep convection drives and maintains an anomalous large-scale east-west overturning circulation with rising motion over West Africa/eastern Atlantic, and sinking motion over the Caribbean region. The response also includes a strengthening of the West African monsoon, manifested in a northward shift of the West Africa precipitation over land, increased low-level westerlies flow over West Africa at the southern edge of the dust layer, and a near surface westerly jet underneath the dust layer over the Sahara. The dust radiative forcing also leads to significant changes in surface energy fluxes, resulting in cooling of the West African land and the eastern Atlantic, and warming in the West Atlantic and Caribbean. The EHP effect is most effective for moderate to highly absorbing dusts, and becomes minimized for reflecting dust with single

  19. International Commodity Markets, Local Food Prices and Environment in West Africa

    NASA Astrophysics Data System (ADS)

    Brown, M. E.; Hintermann, B.; Higgins, N.

    2008-12-01

    The recent massive increase in food and energy prices in the past five years, coupled with the awareness of the long term challenges of climate change to small holder agriculture in Africa has brought the issue of food security for the world's poorest people to the forefront once again. Asymmetric and limited integration of local commodity markets in West Africa highlights the weak position of Africa's rural countries in the face of climate change and demographic expansion. This paper will describe the functioning of local informal food markets in West African over the past twenty years and evaluate the impact of their limited integration with each other and with global commodity markets. Satellite remote sensing of vegetation has been used as a proxy for agricultural production in economic models to improve prediction of large swings in prices from year to year due to differences in supply. As demand increases, improvements in market functioning will be necessary to counter likely increases in production variability. Increasing Africa's stability in the face of climate change will require investment in agricultural production and transportation infrastructure in order to ensure an affordable flow of food to people in these extremely poor, landlocked countries.

  20. Drought modes in West Africa and how well CORDEX RCMs simulate them

    NASA Astrophysics Data System (ADS)

    Diasso, Ulrich; Abiodun, Babatunde J.

    2015-12-01

    This study presents the spatial-temporal structure of droughts in West Africa and evaluates the capability of CORDEX regional climate models in simulating the droughts. The study characterize droughts with the standardized evapo-transpiration index (SPEI) computed using the monthly rainfall and temperature data from the Climatic Research Unit (CRU) and CORDEX models simulation datasets. To obtain the spatial-temporal structure of the droughts, we applied the principal component analysis on the observed and simulated SPEIs and retained the first four principal factors as the leading drought modes over West Africa. The relationship between the drought modes and atmospheric teleconnections was studied using wavelet coherence analysis, while the ability of the CORDEX models to simulate the drought modes was quantified with correlation analysis. The analysis of the relationship between drought modes and atmospheric teleconnections is based on SPEI from observation dataset (CRU). The study shows that about 60 % of spatial-temporal variability in SPEI over West Africa can be grouped into four drought modes. The first drought mode features drought over east Sahel, the second over west Sahel, the third over the Savanna, and the fourth over the Guinea coast. Each drought mode is linked to sea surface temperature anomalies (SSTAs) over tropical areas of Pacific, Atlantic, and Indian Oceans. Most CORDEX models reproduce at least two of the drought modes, but only two models (REMO and CNRM) reproduce all the four drought modes. REMO and WRF give the best simulation of the seasonal variation of the drought mode over the Sahel in March-May and June-August seasons, while CNRM gives the best simulation of seasonal variation in the drought pattern over the Savanna. Results of this study may guide in selecting appropriate CORDEX models for seasonal prediction of droughts and for downscaling projected impacts of global warming on droughts in West Africa.

  1. Evaluating the performance of remotely sensed and reanalysed precipitation data over West Africa using HBV light

    NASA Astrophysics Data System (ADS)

    Jütten, Thomas; Jackisch, Dominik; Diekkrüger, Bernd; Kusche, Jürgen; Eicker, Annette; Springer, Anne

    2016-04-01

    Water is one of the most crucial natural resources in West Africa, where the livelihoods of large parts of the population rely heavily on rain-fed agriculture. Therefore, the modelling of the water balance is an important tool to aid in water resource management. Precipitation is one of most important atmospheric drivers of hydrological models. However, ground-based observation networks are sparse in Western Africa and a further decline in station numbers due to a variety of reasons such as the deterioration of stations or political unrest has been observed in recent years. In ungauged river basins, or basins with insufficiently available precipitation data, several studies have shown that remotely sensed or reanalysed precipitation data may be used to compliment or replace missing information. However, the uncertainties of these datasets over Western Africa are not well examined and a need for further studies is apparent. For validation purposes, precipitation datasets are traditionally compared to in-situ ground measurements. This is not possible in ungauged basins. A new approach to assess the quality of satellite and reanalysis data which is gaining popularity among researchers compares different precipitation datasets using hydrological models. In this so-called hydrological evaluation, ground-truth data is no longer necessary in order to validate a product. The chosen model is calibrated for different precipitation products and the simulated streamflow generated for each product is compared to the measured streamflow. Multiple state of the art satellite and reanalysis precipitation datasets with various spatial resolutions were used in this study, namely: CFSR (0.3125°), CHIRPS (0.05°), CMORPH (0.25°), PERSIANN (0.25°), RFE 2.0 (0.1°), TAMSAT (0.0375°), TRMM 3B42 v7 (0.25°) and TRMM 3B42RT (real time) (0.25°). These datasets were evaluated at the regional as well as local scale using the HBV light conceptual hydrological model for several basins

  2. Predicted impacts of climate change on malaria transmission in West Africa

    NASA Astrophysics Data System (ADS)

    Yamana, T. K.; Eltahir, E. A. B.

    2014-12-01

    Increases in temperature and changes in precipitation due to climate change are expected to alter the spatial distribution of malaria transmission. This is especially true in West Africa, where malaria prevalence follows the current north-south gradients in temperature and precipitation. We assess the skill of GCMs at simulating past and present climate in West Africa in order to select the most credible climate predictions for the periods 2030-2060 and 2070-2100. We then use the Hydrology, Entomology and Malaria Transmission Simulator (HYDREMATS), a mechanistic model of malaria transmission, to translate the predicted changes in climate into predicted changes availability of mosquito breeding sites, mosquito populations, and malaria prevalence. We investigate the role of acquired immunity in determining a population's response to changes in exposure to the malaria parasite.

  3. What aspects of future rainfall changes matter for crop yields in West Africa?

    NASA Astrophysics Data System (ADS)

    Guan, Kaiyu; Sultan, Benjamin; Biasutti, Michela; Baron, Christian; Lobell, David B.

    2015-10-01

    How rainfall arrives, in terms of its frequency, intensity, the timing and duration of rainy season, may have a large influence on rainfed agriculture. However, a thorough assessment of these effects is largely missing. This study combines a new synthetic rainfall model and two independently validated crop models (APSIM and SARRA-H) to assess sorghum yield response to possible shifts in seasonal rainfall characteristics in West Africa. We find that shifts in total rainfall amount primarily drive the rainfall-related crop yield change, with less relevance to intraseasonal rainfall features. However, dry regions (total annual rainfall below 500 mm/yr) have a high sensitivity to rainfall frequency and intensity, and more intense rainfall events have greater benefits for crop yield than more frequent rainfall. Delayed monsoon onset may negatively impact yields. Our study implies that future changes in seasonal rainfall characteristics should be considered in designing specific crop adaptations in West Africa.

  4. Non-biomedical factors in the Ebola virus disease outbreak in West Africa.

    PubMed

    Adachi, Takuya

    2015-01-01

    The outbreak of Ebola virus disease, reported in West Africa in 2014, has become the largest ever one in the history. Tremendous efforts by all the parties concerned are now bringing this epidemic closer to the end, while observing a large number of cases and deaths, including health care workers.This paper features five questions:1. Why did it emerge in West Africa?2. Why has it spread so wide and intensely?3. Why were so many health care workers infected?4. Why is it being brought under control?5. Would it emerge and spread in Japan in the same way?Ebola virus transmits through human acts such as caregiving of the sick and attending a funeral, therefore an epidemic is not likely to subside naturally, but intentional interventions are needed to terminate its transmission. Who the outbreak response is meant for, either patients, the general public in the affected countries, or international communities, also determines its success or failure.

  5. Secondary Organic Aerosol from biogenic VOCs over West Africa during AMMA

    NASA Astrophysics Data System (ADS)

    Capes, G.; Murphy, J. G.; Reeves, C. E.; McQuaid, J. B.; Hamilton, J. F.; Hopkins, J. R.; Crosier, J.; Williams, P. I.; Coe, H.

    2009-01-01

    This paper presents measurements of organic aerosols above subtropical West Africa during the wet season using data from the UK Facility for Airborne Atmospheric Measurements (FAAM) aircraft. Measurements of biogenic volatile organic compounds (BVOC) at low altitudes over these subtropical forests were made during the African Monsoon Multidisciplinary Analysis (AMMA) field experiment during July and August 2006 mainly above Benin, Nigeria and Niger. Data from an Aerodyne Quadrupole Aerosol Mass Spectrometer show a median organic aerosol loading of 1.08 μg m-3 over tropical West Africa, which represents the first regionally averaged assessment of organic aerosol mass (OM) in this region during the wet season. This is in good agreement with predictions based on aerosol yields from isoprene and monoterpenes during chamber studies and model predictions based on partitioning schemes, contrasting markedly with the large under representations of OM in similar models when compared with data from mid latitudes.

  6. The possible role of local air pollution in climate change in West Africa

    NASA Astrophysics Data System (ADS)

    Knippertz, Peter; Evans, Mat J.; Field, Paul R.; Fink, Andreas H.; Liousse, Catherine; Marsham, John H.

    2015-09-01

    The climate of West Africa is characterized by a sensitive monsoon system that is associated with marked natural precipitation variability. This region has been and is projected to be subject to substantial global and regional-scale changes including greenhouse-gas-induced warming and sea-level rise, land-use and land-cover change, and substantial biomass burning. We argue that more attention should be paid to rapidly increasing air pollution over the explosively growing cities of West Africa, as experiences from other regions suggest that this can alter regional climate through the influences of aerosols on clouds and radiation, and will also affect human health and food security. We need better observations and models to quantify the magnitude and characteristics of these impacts.

  7. Family Planning Programmes in Africa.

    ERIC Educational Resources Information Center

    Pradervand, Pierre

    The countries discussed in this paper are the francophone countries of West Africa and the Republic of Congo, with comparative references made to North Africa (mainly Morocco, Algeria, and Tunisia). Obstacles to the adoption of family planning in the countries of tropical Africa are a very high mortality rate among children; a socioeconomic…

  8. Assessment of Undiscovered Oil and Gas Resources of Four West Africa Geologic Provinces

    USGS Publications Warehouse

    Brownfield, Michael E.; Charpentier, Ronald R.; Cook, Troy A.; Klett, Timothy R.; Pitman, Janet K.; Pollastro, Richard M.; Schenk, Christopher J.; Tennyson, Marilyn E.

    2010-01-01

    Four geologic provinces located along the northwest and west-central coast of Africa recently were assessed for undiscovered oil, natural gas, and natural gas liquids resources as part of the U.S. Geological Survey's (USGS) World Oil and Gas Assessment. Using a geology-based assessment methodology, the USGS estimated mean volumes of 71.7 billion barrels of oil, 187.2 trillion cubic feet of natural gas, and 10.9 billion barrels of natural gas liquids.

  9. Improving regional health care in West Africa using current space systems and technology

    NASA Technical Reports Server (NTRS)

    Jemison, Mae C.; Thomas, J. Segun

    1992-01-01

    This paper discusses the issues involved with establishing an integrated satellite health network in West Africa based on currently available technology. The system proposed makes use of a central national facility capable of transmitting and receiving voice/data and video signals from the entire country. Regional, field and local facilities provide timely epidemiologic information, sharing of medical expertise through telemedical consultations, enhance optimized resource distribution and build a framework for telecommunications for the entire country.

  10. Improving regional health care in West Africa using current space systems and technology

    NASA Technical Reports Server (NTRS)

    Jemison, Mae C.; Thomas, J. S.

    1992-01-01

    This paper discusses the issues involved with establishing an integrated satellite health network in West Africa based on currently available technology. The system proposed makes use of a central national facility capable of transmitting and receiving voice/data and video signals from the entire country. Regional, field and local facilities provides timely epidemiologic information, sharing of medical expertise through telemedical consultations, enhances optimized resource distribution and builds a framework for telecommunications for the entire country.

  11. Climate change mitigation by carbon stock - the case of semi-arid West Africa

    NASA Astrophysics Data System (ADS)

    Lykke, A. M.; Barfod, A. S.; Tinggaard Svendsen, G.; Greve, M.; Svenning, J.-C.

    2009-11-01

    Semi-arid West Africa has not been integrated into the afforestation/reforestation (AR) carbon market. Most projects implemented under the Clean Development Mechanism (CDM) have focused on carbon emission reductions from industry and energy consumption, whereas only few (only one in West Africa) have been certified for AR carbon sequestration. A proposed mechanism, Reducing Emissions from Deforestation and Degradation (REDD) to be discussed under COP15 aims to reduce emissions by conserving already existing forests. REDD has high potential for carbon stocking at low costs, but focuses primarily on rain forest countries and excludes semi-arid West Africa from the preliminary setup. African savannas have potential to store carbon in the present situation with degrading ecosystems and relatively low revenues from crops and cattle, especially if it is possible to combine carbon stocking with promotion of secondary crops such as food resources and traditional medicines harvested on a sustainable basis. Methods for modelling and mapping of potential carbon biomass are being developed, but are still in a preliminary state. Although economic benefits from the sale of carbon credits are likely to be limited, carbon stocking is an interesting option if additional benefits are considered such as improved food security and protection of biodiversity.

  12. The British and curriculum development in West Africa: A historical discourse

    NASA Astrophysics Data System (ADS)

    Ofori-Attah, Kwabena Dei

    2006-09-01

    THE BRITISH AND CURRICULUM DEVELOPMENT IN WEST AFRICA: A HISTORICAL STUDY - Only recently have African nations begun to make their way towards establishing genuinely autonomous education systems incorporating elements of indigenous culture. The present study examines the historical development of curriculum in British West Africa in its links with the educational activities of the early Christian missionaries and the imposition of British colonial rule. For over 300 years, the curriculum content was essentially European in nature. African interests and cultural practices were largely excluded, as "bookwork" was favored over "handwork". The colonial curriculum also helped introduce a new social order to West Africa, leading to the rise of new local elites reading, writing, and speaking foreign European languages. This study explores how the idea of a "civilized" person, promoted through the colonial school curriculum, developed new local elites with different sets of values and expectations that often made them strangers in their own societies. It also describes the connection between this curriculum and the repeated failure of education-reform efforts.

  13. Secondary Organic Aerosol from Biogenic VOCs over West Africa during AMMA

    NASA Astrophysics Data System (ADS)

    Capes, G. L.; Murphy, J. G.; Reeves, C. E.; McQuaid, J. B.; Hamilton, J. F.; Hopkins, J. R.; Coe, H.

    2008-12-01

    As part of the international AMMA (African Monsoon Multidisciplinary Analyses) project a large field experiment took place in West Africa during July and August 2006. This involved a number of ground-based facilities and 5 aircraft, including the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146, which was based in Niamey, Niger and made 21 flights. The 146 was equipped with instruments measuring parameters relevant to dynamics, gas phase composition, radiation, aerosols and clouds. The flights made were designed to examine a range of multidisciplinary scientific questions. This paper presents measurements of organic aerosol above subtropical West Africa during the monsoon season using data from the FAAM aircraft. Measurements of biogenic volatile organic compounds (BVOC) at low altitudes over these subtropical forests were made during July and August 2006 mainly above Benin, Nigeria and Niger. In air masses characterised by high BVOC concentrations, data from an Aerodyne Quadrupole Aerosol Mass Spectrometer show an organic aerosol loading of 0.58 μgm-3 over tropical West Africa. In contrast, organic aerosol mass (OM) concentrations were negligible when BVOC concentrations were low. This represents the first regionally averaged assessment of OM in this region during the wet season. This is in good agreement with predictions based on aerosol yields from isoprene and monoterpenes during chamber studies and model predictions based on partitioning schemes, contrasting markedly with the large under representations of OM in similar models when compared with data from mid latitudes.

  14. Safe and Effective Deployment of Personnel to Support the Ebola Response - West Africa.

    PubMed

    Rouse, Edward N; Zarecki, Shauna Mettee; Flowers, Donald; Robinson, Shawn T; Sheridan, Reed J; Goolsby, Gary D; Nemhauser, Jeffrey; Kuwabara, Sachiko

    2016-07-08

    From the initial task of getting "50 deployers within 30 days" into the field to support the 2014-2016 Ebola virus disease (Ebola) epidemic response in West Africa to maintaining well over 200 staff per day in the most affected countries (Guinea, Liberia, and Sierra Leone) during the peak of the response, ensuring the safe and effective deployment of international responders was an unprecedented accomplishment by CDC. Response experiences shared by CDC deployed staff returning from West Africa were quickly incorporated into lessons learned and resulted in new activities to better protect the health, safety, security, and resiliency of responding personnel. Enhanced screening of personnel to better match skill sets and experience with deployment needs was developed as a staffing strategy. The mandatory predeployment briefings were periodically updated with these lessons to ensure that staff were aware of what to expect before, during, and after their deployments. Medical clearance, security awareness, and resiliency programs became a standard part of both predeployment and postdeployment activities. Response experience also led to the identification and provision of more appropriate equipment for the environment. Supporting the social and emotional needs of deployed staff and their families also became an agency focus for care and communication. These enhancements set a precedent as a new standard for future CDC responses, regardless of size or complexity.The activities summarized in this report would not have been possible without collaboration with many U.S and international partners (http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/partners.html).

  15. Understanding changes in terrestrial water storage over West Africa between 2002 and 2014

    NASA Astrophysics Data System (ADS)

    Ndehedehe, Christopher; Awange, Joseph; Agutu, Nathan; Kuhn, Michael; Heck, Bernhard

    2016-02-01

    With the vast water resources of West Africa coming under threat due to the impacts of climate variability and human influence, the need to understand its terrestrial water storage (TWS) changes becomes very important. Due to the lack of consistent in-situ hydrological data to assist in the monitoring of changes in TWS, this study takes advantage of the Gravity Recovery and Climate Experiment (GRACE) monthly gravity fields to provide estimates of vertically integrated changes in TWS over the period 2002-2014, in addition to satellite altimetry data for the period 1993-2014. In order to understand TWS variability over West Africa, Principal Component Analysis (PCA), a second order statistical technique, and Multiple Linear Regression Analysis (MLRA) are employed. Results show that dominant patterns of GRACE-derived TWS changes are observed mostly in the West Sahel, Guinea Coast, and Middle Belt regions of West Africa. This is probably caused by high precipitation rates at seasonal and inter-annual time scales induced by ocean circulations, altitude and physiographic features. While the linear trend for the spatially averaged GRACE-derived TWS changes over West Africa for the study period shows an increase of 6.85 ± 1.67 mm/yr, the PCA result indicates a significant increase of 20.2 ± 5.78 mm/yr in Guinea, a region with large inter-annual variability in seasonal rainfall, heavy river discharge, and huge groundwater potentials. The increase in GRACE-derived TWS during this period in Guinea, though inconsistent with the lack of a significant positive linear trend in TRMM based precipitation, is attributed to a large water surplus from prolonged wet seasons and lower evapotranspiration rates, leading to an increase in storage and inundated areas over the Guinea region. This increase in storage, which is also the aftermath of cumulative increase in the volume of water not involved in surface runoff, forms the huge freshwater availability in this region. However, the

  16. Tracer redistribution by clouds in West Africa: Numerical modeling for dry and wet seasons

    SciTech Connect

    Renard, M.; Chaumerliac, N.; Cautenet, S.; Nickerson, E.C. |

    1994-06-01

    The vertical transport by clouds of an inert tracer and its redistribution by complex West African circulations are examined using a two-dimensional mesoscale meteorological model with explicit microphysics. The model reproduces the tropical distribution of clouds and precipitation along a meridional cross section over West Africa, corresponding to the position of the Intertropical Convergence Zone (ITCZ) during the dry and rainy seasons. The resulting redistribution of the inert tracer is therefore closely related to the northward migration of the ITCZ between January and July. The occurrence of biomass burning during the dry season is shown to be an important source of tracer enrichment at upper levels in the atmosphere.

  17. A-level Biology in West Africa: A New Syllabus

    ERIC Educational Resources Information Center

    Ewer, D. W.

    1969-01-01

    Describes a biology course developed for West African senior high school students. Ecology is used as an integrating theme, and the approach is problem centered. Discusses the proposed form of examinations in the course. (EB)

  18. Virtual Reference Service in Academic Libraries in West Africa

    ERIC Educational Resources Information Center

    Sekyere, Kwabena

    2011-01-01

    As technology continues to advance, libraries in Europe and America continue to improve upon their virtual reference services by employing new Web technologies and applying them to existing services. West African academic libraries have begun providing resources electronically to their users but still typically lag behind in the services they…

  19. Polyglots, Vernaculars and Global Markets: Variable Trends in West Africa

    ERIC Educational Resources Information Center

    Adejunmobi, Moradewun

    2004-01-01

    Using a framework from cultural studies and focusing on theories put forward by Pierre Bourdieu, the goal in this paper is to consider how some West Africans interact with foreign languages and cultures in an era of global capital, especially when it comes to the activities of migrants venturing into overseas labour markets and to the production…

  20. Missionary Education in West Africa: A Study of Pedagogical Ambition

    ERIC Educational Resources Information Center

    Ustorf, Werner

    2011-01-01

    The history of the North German Mission Society (established 1836 in Hamburg) and its activity on the West African coast (from 1847 onwards among the Ewe, in what is now Ghana and Togo where it was and still is known as the "Bremen Mission") mirrors neatly the various phases of the idea of "mission": its composite motivation…

  1. Discovering Karima (Euphorbiaceae), a New Crotonoid Genus from West Tropical Africa Long Hidden within Croton

    PubMed Central

    Cheek, Martin; Challen, Gill; Lebbie, Aiah; Banks, Hannah; Barberá, Patricia; Riina, Ricarda

    2016-01-01

    Croton scarciesii (Euphorbiaceae-Crotonoideae), a rheophytic shrub from West Africa, is shown to have been misplaced in Croton for 120 years, having none of the diagnostic characters of that genus, but rather a set of characters present in no known genus of the family. Pollen analysis shows that the new genus Karima belongs to the inaperturate crotonoid group. Analysis of a concatenated molecular dataset combining trnL-F and rbcL sequences positioned Karima as sister to Neoholstia from south eastern tropical Africa in a well-supported clade comprised of genera of subtribes Grosserineae and Neoboutonieae of the inaperturate crotonoid genera. Several morphological characters support the relationship of Karima with Neoholstia, yet separation is merited by numerous characters usually associated with generic rank in Euphorbiaceae. Quantitative ecological data and a conservation assessment supplement illustrations and descriptions of the taxon. PMID:27049519

  2. Ebola virus disease control in West Africa: an ecological, one health approach.

    PubMed

    Meseko, Clement Adebajo; Egbetade, Adeniyi Olugbenga; Fagbo, Shamsudeen

    2015-01-01

    The 2013-2015 Ebola Virus Disease outbreak in West Africa had similar nuances with the 1976 outbreaks in Central Africa; both were caused by the Zaire Ebola Virus strain and originated from rural forested communities. The definitive reservoir host of Ebola virus still remains unknown till date. However, from ecological perspective, it is known that the virus first emerged from forest ecotypes interfacing with human activities. As at March 2015, the outbreak has claimed over 9000 lives, which is unprecedented. Though it remains unproved, the primary sources of infection for past and present outbreaks are forest dwelling, human-hunted fauna. Understanding the ecological factors at play in these forest ecotypes where wild fauna interface with human and causing pathogen spill over is important. A broad based One Health approach incorporating these ecological concepts in the control of Ebola Virus Disease can effectively ameliorate or forestall infection now and in the future.

  3. Discovering Karima (Euphorbiaceae), a New Crotonoid Genus from West Tropical Africa Long Hidden within Croton.

    PubMed

    Cheek, Martin; Challen, Gill; Lebbie, Aiah; Banks, Hannah; Barberá, Patricia; Riina, Ricarda

    2016-01-01

    Croton scarciesii (Euphorbiaceae-Crotonoideae), a rheophytic shrub from West Africa, is shown to have been misplaced in Croton for 120 years, having none of the diagnostic characters of that genus, but rather a set of characters present in no known genus of the family. Pollen analysis shows that the new genus Karima belongs to the inaperturate crotonoid group. Analysis of a concatenated molecular dataset combining trnL-F and rbcL sequences positioned Karima as sister to Neoholstia from south eastern tropical Africa in a well-supported clade comprised of genera of subtribes Grosserineae and Neoboutonieae of the inaperturate crotonoid genera. Several morphological characters support the relationship of Karima with Neoholstia, yet separation is merited by numerous characters usually associated with generic rank in Euphorbiaceae. Quantitative ecological data and a conservation assessment supplement illustrations and descriptions of the taxon.

  4. Multivariate Prediction of Total Water Storage Changes Over West Africa from Multi-Satellite Data

    NASA Astrophysics Data System (ADS)

    Forootan, Ehsan; Kusche, Jürgen; Loth, Ina; Schuh, Wolf-Dieter; Eicker, Annette; Awange, Joseph; Longuevergne, Laurent; Diekkrüger, Bernd; Schmidt, Michael; Shum, C. K.

    2014-07-01

    West African countries have been exposed to changes in rainfall patterns over the last decades, including a significant negative trend. This causes adverse effects on water resources of the region, for instance, reduced freshwater availability. Assessing and predicting large-scale total water storage (TWS) variations are necessary for West Africa, due to its environmental, social, and economical impacts. Hydrological models, however, may perform poorly over West Africa due to data scarcity. This study describes a new statistical, data-driven approach for predicting West African TWS changes from (past) gravity data obtained from the gravity recovery and climate experiment (GRACE), and (concurrent) rainfall data from the tropical rainfall measuring mission (TRMM) and sea surface temperature (SST) data over the Atlantic, Pacific, and Indian Oceans. The proposed method, therefore, capitalizes on the availability of remotely sensed observations for predicting monthly TWS, a quantity which is hard to observe in the field but important for measuring regional energy balance, as well as for agricultural, and water resource management. Major teleconnections within these data sets were identified using independent component analysis and linked via low-degree autoregressive models to build a predictive framework. After a learning phase of 72 months, our approach predicted TWS from rainfall and SST data alone that fitted to the observed GRACE-TWS better than that from a global hydrological model. Our results indicated a fit of 79 % and 67 % for the first-year prediction of the two dominant annual and inter-annual modes of TWS variations. This fit reduces to 62 % and 57 % for the second year of projection. The proposed approach, therefore, represents strong potential to predict the TWS over West Africa up to 2 years. It also has the potential to bridge the present GRACE data gaps of 1 month about each 162 days as well as a—hopefully—limited gap between GRACE and the GRACE

  5. Infrared radiation budget of the Harmattan haze. [West Africa

    NASA Technical Reports Server (NTRS)

    Kuhn, P. M.; Weickmann, H. K.

    1975-01-01

    Infrared in situ observations of the West African Harmaltan Haze during the 1974 GATE field phase were conducted to determine the radiative properties of the tropospheric phenomenon and to develop a calculation model for radiative transfer through the haze. Radiometric observations of the dust haze were analyzed for haze infrared transmission. Infrared and tropospheric cooling rates are given together with the haze volume absorption rate.

  6. An update on distribution models for Rhipicephalus microplus in West Africa.

    PubMed

    De Clercq, Eva M; Estrada-Peña, Agustin; Adehan, S; Madder, Maxime; Vanwambeke, Sophie O

    2013-11-01

    The cattle tick, Rhipicephalus microplus, which reached the West African region approximately 8 years ago, has established viable populations in Côte d'Ivoire and Benin and spread rapidly from the assumed points of introduction. However, existing maps of its distribution range do not agree on the areas at risk, most probably due to suboptimal modelling approaches. Therefore, we undertook a re-investigation of the potential distribution range based on a high-quality dataset from West Africa that includes information on 104 farms located all over Benin. Focussing on climate suitability and applying advanced modelling, a subset of representative and uncorrelated climate variables was selected and fed into Maxent software to obtain an estimate of climate suitability for West Africa. The resulting map was validated using an independent dataset of 13 farms along the apparent distribution edge. The entire southern part of West Africa (covering southern Nigeria, Benin, Togo and Ghana) features high climate suitability for R. microplus. All of Côte d'Ivoire is inside the distribution range of this tick and the southern rim of Burkina Faso is expected to be suitable for the establishment of R. microplus populations. The validation of the distribution, dated one year after the initial field visit, confirmed the predicted distribution range, although a small number of individuals of R. microplus were found north of the predicted limit. These low numbers might indicate that the climate is not suitable for the establishment of a viable tick population. An alternative explanation is the recent introduction by nomadic cattle herds passing through this location. In this region of the world, it is quite common for cattle owners to lead their livestock over distances of more than 500 km in search of food and water.

  7. The WASCAL regional climate simulations for West Africa - how to add value to existing climate projections

    NASA Astrophysics Data System (ADS)

    Arnault, J.; Heinzeller, D.; Klein, C.; Dieng, D.; Smiatek, G.; Bliefernicht, J.; Sylla, M. B.; Kunstmann, H.

    2015-12-01

    With climate change being one of the most severe challenges to rural Africa in the 21st century, West Africa is facing an urgent need to develop effective adaptation and mitigation measures to protect its constantly growing population. WASCAL (West African Science Service Center on Climate Change and Adapted Land Use) is a large-scale research-focused program designed to enhance the resilience of human and environmental systems to climate change and increased variability. An integral part of its climate services is the provisioning of a new set of high resolution, ensemble-based regional climate change scenarios for the region of West Africa. In this contribution, we present the overall concept of the WASCAL regional climate projections and provide information on the dissemination of the data. We discuss the model performance over the validation period for two of the three regional climate models employed, the Weather Research & Forecasting Tool (WRF) and the Consortium for Small-scale Modeling Model COSMO in Climate Mode (COSMO-CLM), and give details about a novel precipitation database used to verify the models. Particular attention is paid to the representation of the dynamics of the West African Summer Monsoon and to the added value of our high resolution models over existing data sets. We further present results on the climate change signal obtained from the WRF model runs for the periods 2020-2050 and 2070-2100 and compare them to current state-of-the-art projections from the CORDEX project. As an example, the figure shows the different climate change signals obtained for the total annual rainfall with respect to the 1980-2010 mean (WRF-E: WASCAL 12km high-resolution run MPI-ESM + WRFV3.5.1, CORDEX-E: 50km medium-resolution run MPI-ESM + RCA4, CORDEX-G: 50km medium-resolution run GFDL-ESM + RCA4).

  8. Effects of vegetation feedback on future climate change over West Africa

    NASA Astrophysics Data System (ADS)

    Yu, Miao; Wang, Guiling; Pal, Jeremy S.

    2016-06-01

    This study investigates the impact of climate-vegetation interaction on future climate changes over West Africa using a regional climate model with synchronous coupling between climate and natural vegetation, the RegCM4.3.4-CLM-CN-DV. Based on the lateral boundary conditions supplied by MIROC-ESM and CESM under the greenhouse gas Representative Concentration Pathway 8.5, significant increase of vegetation density is projected over the southern part of Sahel, with an increase of leaf area index and a conversion from grass to woody plants around 7-10°N of Sahel. Regardless of whether the model treats vegetation as static or dynamic, it projects an increase of precipitation in eastern Sahel and decrease in the west. The feedback due to projected vegetation change tends to cause a wet signal, enhancing the projected increase or alleviate the decrease of precipitation in JJA in the areas of projected vegetation increase. Its impact is negligible in DJF. Vegetation feedback slightly enhances projected warming in most of West Africa during JJA, but has a significant cooling effect during DJF in regions of strong vegetation changes. Future changes of surface runoff are projected to follow the direction of precipitation changes. While dynamic vegetation feedback enhances the projected increase of soil water content in JJA, it has a drying effect in DJF. The magnitude of projected ET changes is reduced in JJA and increased in DJF due to vegetation dynamics. A high sensitivity of climate projection to dynamic vegetation feedback was found mainly in semiarid areas of West Africa, with little signal in the wet tropics.

  9. Forecasting droughts in West Africa: Operational practice and refined seasonal precipitation forecasts

    NASA Astrophysics Data System (ADS)

    Bliefernicht, Jan; Siegmund, Jonatan; Seidel, Jochen; Arnold, Hanna; Waongo, Moussa; Laux, Patrick; Kunstmann, Harald

    2016-04-01

    Precipitation forecasts for the upcoming rainy seasons are one of the most important sources of information for an early warning of droughts and water scarcity in West Africa. The meteorological services in West Africa perform seasonal precipitation forecasts within the framework of PRESAO (the West African climate outlook forum) since the end of the 1990s. Various sources of information and statistical techniques are used by the individual services to provide a harmonized seasonal precipitation forecasts for decision makers in West Africa. In this study, we present a detailed overview of the operational practice in West Africa including a first statistical assessment of the performance of the precipitation forecasts for drought situations for the past 18 years (1998 to 2015). In addition, a long-term hindcasts (1982 to 2009) and a semi-operational experiment for the rainy season 2013 using statistical and/or dynamical downscaling are performed to refine the precipitation forecasts from the Climate Forecast System Version 2 (CFSv2), a global ensemble prediction system. This information is post-processed to provide user-oriented precipitation indices such as the onset of the rainy season for supporting water and land use management for rain-fed agriculture. The evaluation of the individual techniques is performed focusing on water-scarce regions of the Volta basin in Burkina Faso and Ghana. The forecasts of the individual techniques are compared to state-of-the-art global observed precipitation products and a novel precipitation database based on long-term daily rain-gage measurements provided by the national meteorological services. The statistical assessment of the PRESAO forecasts indicates skillful seasonal precipitation forecasts for many locations in the Volta basin, particularly for years with water deficits. The operational experiment for the rainy season 2013 illustrates the high potential of a physically-based downscaling for this region but still shows

  10. Diagnosis and Modelling of the Variability of Rainfall in West Africa Within the Impetus Project

    NASA Astrophysics Data System (ADS)

    Fink, A. H.; Born, K.; Hense, A.; Kerschgens, M.; Paeth, H.; Schulz, J.; Simmer, C.; Sogalla, M.; Speth, P.

    2003-04-01

    In the meteorological sub-project of the multi-disciplinary IMPETUS project ('An Integrated Approach to the Efficient Management of Scarce Water Resources in West Africa'), one focus is on the diagnosis and modelling of the major rainfall producing weather systems in Benin and Morocco. Two other foci are on model sensitivity studies to determine the potential of seasonal rainfall forecasting for tropical West Africa, as well as on the impact of land surface characteristics on rainfall patterns. Recent analysis of precipitation trends reveals no return to normal or above-normal monsoon rains in all climatic zones of tropical West Africa. In Morocco, a series of dry winters in the winter-precipitation regime north of the High Atlas occurred in the 1980s and 1990s, while at the Saharan foothills of the Atlas Mountains, wetter than normal conditions prevailed. This behaviour might be explained by a hitherto poorly examined contribution of "Tropical Extratropical Interaction" (TEI) events to the mean annual rainfall south of the Atlas mountains. Such TEI most often occur in the transition seasons and cause convective rainfall events that are supplied with water vapour from tropical moisture plumes. In the West African Tropics, the effect of interactions between the earth's surface and the atmosphere on fresh water availability is investigated with a non-hydrostatic mesoscale model for a river catchment in Benin. Idealised ensemble studies exhibit a dominant influence of initial soil water content and an enhanced dependence of precipitation on vegetation when soil water availability is reduced. It is also shown that a successive increase of the fraction of degraded land surface results in a nearly linear response of moderate rainfall decrease for the area as a whole and a tendency to strong reductions in some regions. Finally, observational data sets and output from the global (ECHAM4) and continental (REMO) general circulation models are used to determine the potential

  11. Climate change unlikely to increase malaria burden in West Africa

    NASA Astrophysics Data System (ADS)

    Yamana, Teresa K.; Bomblies, Arne; Eltahir, Elfatih A. B.

    2016-11-01

    The impact of climate change on malaria transmission has been hotly debated. Recent conclusions have been drawn using relatively simple biological models and statistical approaches, with inconsistent predictions. Consequently, the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5) echoes this uncertainty, with no clear guidance for the impacts of climate change on malaria transmission, yet recognizing a strong association between local climate and malaria. Here, we present results from a decade-long study involving field observations and a sophisticated model simulating village-scale transmission. We drive the malaria model using select climate models that correctly reproduce historical West African climate, and project reduced malaria burden in a western sub-region and insignificant impact in an eastern sub-region. Projected impacts of climate change on malaria transmission in this region are not of serious concern.

  12. An Inquiry-based Astronomy Summer School in West Africa

    NASA Astrophysics Data System (ADS)

    Strubbe, Linda; Okere, Bonaventure; Chibueze, James; Lepo, Kelly; White, Heidi; Zhang, Jielai; Okoh, Daniel; Reid, Mike; Hunter, Lisa

    2015-01-01

    In October 2013 over 75 undergraduate science students and teachers from Nigeria and Ghana attended the week-long West African International Summer School for Young Astronomers. The school was organized by a collaboration of astronomers from the University of Toronto, the University of Nigeria, and the Nigerian National Space Research and Development Agency. We designed and led activities that taught astronomy content, promoted students' self-identity as scientists, and encouraged students to think critically and figure out solutions themselves. I will describe the inquiry-based and active learning techniques used in the school, share results from the qualitative and quantitative evaluations of student performance, and describe future plans for holding the school in 2015, supporting our alumni, and building a sustainable partnership between North American and Nigerian universities.

  13. Model-Based Geostatistical Mapping of the Prevalence of Onchocerca volvulus in West Africa

    PubMed Central

    O’Hanlon, Simon J.; Slater, Hannah C.; Cheke, Robert A.; Boatin, Boakye A.; Coffeng, Luc E.; Pion, Sébastien D. S.; Boussinesq, Michel; Zouré, Honorat G. M.; Stolk, Wilma A.; Basáñez, María-Gloria

    2016-01-01

    Background The initial endemicity (pre-control prevalence) of onchocerciasis has been shown to be an important determinant of the feasibility of elimination by mass ivermectin distribution. We present the first geostatistical map of microfilarial prevalence in the former Onchocerciasis Control Programme in West Africa (OCP) before commencement of antivectorial and antiparasitic interventions. Methods and Findings Pre-control microfilarial prevalence data from 737 villages across the 11 constituent countries in the OCP epidemiological database were used as ground-truth data. These 737 data points, plus a set of statistically selected environmental covariates, were used in a Bayesian model-based geostatistical (B-MBG) approach to generate a continuous surface (at pixel resolution of 5 km x 5km) of microfilarial prevalence in West Africa prior to the commencement of the OCP. Uncertainty in model predictions was measured using a suite of validation statistics, performed on bootstrap samples of held-out validation data. The mean Pearson’s correlation between observed and estimated prevalence at validation locations was 0.693; the mean prediction error (average difference between observed and estimated values) was 0.77%, and the mean absolute prediction error (average magnitude of difference between observed and estimated values) was 12.2%. Within OCP boundaries, 17.8 million people were deemed to have been at risk, 7.55 million to have been infected, and mean microfilarial prevalence to have been 45% (range: 2–90%) in 1975. Conclusions and Significance This is the first map of initial onchocerciasis prevalence in West Africa using B-MBG. Important environmental predictors of infection prevalence were identified and used in a model out-performing those without spatial random effects or environmental covariates. Results may be compared with recent epidemiological mapping efforts to find areas of persisting transmission. These methods may be extended to areas where

  14. Comparison of five gridded precipitation products at climatological scales over West Africa

    NASA Astrophysics Data System (ADS)

    Akinsanola, A. A.; Ogunjobi, K. O.; Ajayi, V. O.; Adefisan, E. A.; Omotosho, J. A.; Sanogo, S.

    2016-12-01

    The paper aimed at assessing the capabilities and limitations of five different precipitation products to describe rainfall over West Africa. Five gridded precipitation datasets of the Tropical Rainfall Measurement Mission (TRMM) Multi-Platform Analysis (TMPA 3B43v7); University of Delaware (UDEL version 3.01); Climatic Research Unit (CRU version 3.1); Global Precipitation Climatology Centre (GPCC version 7) and African Rainfall Climatology (ARC version 2) were compared and validated with reference ground observation data from 81 stations spanning a 19-year period, from January 1990 to December 2008. Spatial investigation of the precipitation datasets was performed, and their capability to replicate the inter-annual and intra-seasonal variability was also assessed. The ability of the products to capture the El Nino and La Nina events were also assessed. Results show that all the five datasets depicted similar spatial distribution of mean rainfall climatology, although differences exist in the total rainfall amount for each precipitation dataset. Further analysis shows that the three distinct phases of the mean annual cycle of the West Africa Monsoon precipitation were well captured by the datasets. However, CRU, GPCC and UDEL failed to capture the little dry season in the month of August while UDEL and GPCC underestimated rainfall amount in the Sahel region. Results of the inter-annual precipitation anomalies shows that ARC2 fail to capture about 46% of the observed variability while the other four datasets exhibits a greater performance (r > 0.9). All the precipitation dataset except ARC2 were consistent with the ground observation in capturing the dry and wet conditions associated with El Nino and La Nina events, respectively. ARC2 tends to overestimate the El Nino event and failed to capture the La Nina event in all the years considered. In general GPCC, CRU and TRMM were found to be the most outstanding datasets and can, therefore, be used for precipitation

  15. Decomposing Wealth-Based Inequalities in Under-Five Mortality in West Africa

    PubMed Central

    BADO, Aristide Romaric; APPUNNI, Sathiya Susuman

    2015-01-01

    Background: This study aimed to analysis the inequalities of mortality of children under 5 years in West Africa by examining the determinants and contributing factors to the overall inequality concentration in these countries. Method: Data used came from the DHS surveys conducted in the six countries in West Africa: Burkina Faso (2010), Benin (2006), Cote d’Ivoire 2011), Ghana (2008), Mali (2006), Nigeria (2008) and Niger (2012). The concentration index (CI) and Generalized Linear Model (GLM) with logit link were used to access inequality. Results: The results show that in all countries, the poorest Q1 have the highest proportions of deaths: Nigeria (31.4%), Cote d’Ivoire (30.4%) and Ghana (36.4%), over 30% of deaths of children under 5 years are among the children of the poorest (Q1) and the absolute differences of proportions Q1–Q5 are more than 20 points (25.8 in Ghana and 23.6 in Nigeria). The contributing factors of inequalities of child mortality were birth order, maternal age, parity and household size. Our findings also showed that the intensity of inequality varies from one country to another. Conclusion: The most important conclusion of this study is to reduce mortality in children under 5 years, it is needed to reduce economic and social inequalities and improve the country’s economic and social condition. There is a need for monitoring and assessment inequalities by leading causes of death and morbidity among children in the region in order to advance in understanding the gaps and finding a way to reduce them in West Africa countries. PMID:26576370

  16. Potential Risk of Regional Disease Spread in West Africa through Cross-Border Cattle Trade

    PubMed Central

    Dean, Anna S.; Fournié, Guillaume; Kulo, Abalo E.; Boukaya, G. Aboudou; Schelling, Esther; Bonfoh, Bassirou

    2013-01-01

    Background Transboundary animal movements facilitate the spread of pathogens across large distances. Cross-border cattle trade is of economic and cultural importance in West Africa. This study explores the potential disease risk resulting from large-scale, cross-border cattle trade between Togo, Burkina Faso, Ghana, Benin, and Nigeria for the first time. Methods and Principal Findings A questionnaire-based survey of livestock movements of 226 cattle traders was conducted in the 9 biggest cattle markets of northern Togo in February-March 2012. More than half of the traders (53.5%) operated in at least one other country. Animal flows were stochastically simulated based on reported movements and the risk of regional disease spread assessed. More than three quarters (79.2%, range: 78.1–80.0%) of cattle flowing into the market system originated from other countries. Through the cattle market system of northern Togo, non-neighbouring countries were connected via potential routes for disease spread. Even for diseases with low transmissibility and low prevalence in a given country, there was a high risk of disease introduction into other countries. Conclusions By stochastically simulating data collected by interviewing cattle traders in northern Togo, this study identifies potential risks for regional disease spread in West Africa through cross-border cattle trade. The findings highlight that surveillance for emerging infectious diseases as well as control activities targeting endemic diseases in West Africa are likely to be ineffective if only conducted at a national level. A regional approach to disease surveillance, prevention and control is essential. PMID:24130721

  17. Potential impact of climate and socioeconomic changes on future agricultural land use in West Africa

    NASA Astrophysics Data System (ADS)

    Farzan Ahmed, Kazi; Wang, Guiling; You, Liangzhi; Yu, Miao

    2016-02-01

    Agriculture is a key component of anthropogenic land use and land cover changes that influence regional climate. Meanwhile, in addition to socioeconomic drivers, climate is another important factor shaping agricultural land use. In this study, we compare the contributions of climate change and socioeconomic development to potential future changes of agricultural land use in West Africa using a prototype land use projection (LandPro) algorithm. The algorithm is based on a balance between food supply and demand, and accounts for the impact of socioeconomic drivers on the demand side and the impact of climate-induced crop yield changes on the supply side. The impact of human decision-making on land use is explicitly considered through multiple "what-if" scenarios. In the application to West Africa, future crop yield changes were simulated by a process-based crop model driven with future climate projections from a regional climate model, and future changes of food demand is projected using a model for policy analysis of agricultural commodities and trade. Without agricultural intensification, the climate-induced decrease in crop yield together with future increases in food demand is found to cause a significant increase in cropland areas at the expense of forest and grassland by the mid-century. The increase in agricultural land use is primarily climate-driven in the western part of West Africa and socioeconomically driven in the eastern part. Analysis of results from multiple scenarios of crop area allocation suggests that human adaptation characterized by science-informed decision-making can potentially minimize future land use changes in many parts of the region.

  18. Ocean climate data for user community in West and Central Africa: Needs, opportunities, and challenges

    NASA Technical Reports Server (NTRS)

    Ojo, S. O.

    1992-01-01

    The urgent need to improve data delivery systems needed by scientists studying ocean role in climate and climate characteristics has been manifested in recent years because of the unprecedented climatic events experienced in many parts of the world. Indeed, there has been a striking and growing realization by governments and the general public indicating that national economies and human welfare depend on climate and its variability. In West and Central Africa, for instance climatic events, which have resulted in floods and droughts, have caused a lot of concern to both governments and people of the region. In particular, the droughts have been so widespread that greater awareness and concern have become generated for the need to find solutions to the problems created by the consequences of the climatic events. Particularly in the southern border regions of the Sahara Desert as well as in the Sahel region, the drought episodes considerably reduced food production and led to series of socioeconomic problems, not only in the areas affected by the droughts, but also in the other parts of West Africa. The various climatic variabilities which have caused the climatic events are no doubt related to the ocean-atmosphere interactions. Unfortunately, not much has been done on the understanding of these interactions, particularly as they affect developing countries. Indeed, not much has been done to develop programs which will reflect the general concerns and needs for researching into the ocean-atmosphere systems and their implications on man-environmental systems in many developing countries. This is for example, true of West and Central Africa, where compared with the middle latitude countries, much less is known about the characteristics of the ocean-atmosphere systems and their significance on man-environmental systems of the area.

  19. Long-Term Water Balance of the Volta River Basin in West Africa

    NASA Astrophysics Data System (ADS)

    van de Giesen, N.; Andreini, M.; Taylor, J.; Steenhuis, T.

    2002-12-01

    The Volta River drains approximately 400,000 km2 of the semi-arid to sub-humid savanna of West Africa. Average rainfall is about 1000 mm per year. The interannual variation is relatively low with a coefficient of variation of 0.07. Most rainfall returns to the atmosphere as evapotranspiration and only 9% becomes available as river runoff. The interannual variation of river flow is much higher than that of rainfall and has a coefficient of variation of 0.57. In this presentation, the coupling between interannual variation in rainfall and runoff is examined. To a large extent, the high variability in river flow can be explained with the relatively small differences in rainfall between years; the watershed strongly amplifies the atmospheric input. The amplifying effect is, however, not constant over space and time. Over all, the basin received less rain than before in the past two decades. Some parts of the basin did indeed produce less runoff but other parts actually produced more runoff, most likely due to changes in landuse. No clear increase or decrease in the interannual variability could be found for different parts of the basin. To examine the interannual variability of water resources availability under future climates, the applicability of General Circulation Models (GCMs) was examined for West Africa. Comparison of historical and GCM rainfall data showed large discrepancies. Different approaches exist to adjust GCM rainfall with the aid of historical rainfall data but for West Africa some problems remained. This presentation concludes with a focus on differences in mid-term (2-10 years) persistence in annual river flow as produced by historical and GCM data.

  20. The problem of suboptimal complementary feeding practices in West Africa: what is the way forward?

    PubMed

    Issaka, Abukari I; Agho, Kingsley E; Page, Andrew N; Burns, Penelope L; Stevens, Garry J; Dibley, Michael J

    2015-10-01

    The objective of this paper was to review the policy implications of inadequate complementary feeding among children aged 6-23 months in West Africa. The review was undertaken from the initial results and findings from a series of studies on the comparison of complementary feeding indicators among children aged 6-23 months in four anglophone and seven francophone West African countries. It also examined a study of the determinants of suboptimal complementary feeding practices among children aged 6-23 months in those countries. Among the four complementary feeding indicators, it was only the introduction of solid, semi-solid or soft foods that was adequate among children in all the West African countries surveyed. The rates of the other complementary feeding indicators were found to be inadequate in all countries surveyed, although relatively better among children in the anglophone countries. Alarmingly, low rates of minimum acceptable diet were reported among children from both the anglophone and the francophone countries. Infants 6-11 months of age, children living in poor households, administrative/geographical regional differences and mothers' access to the media were some of the common risk factors for optimal complementary feeding practices in these countries. Assessing complementary feeding indicators and determinants of suboptimal complementary feeding practices in these West African countries is crucial to improving infant and young child feeding practices. It is recommended that governments and stakeholders of the West African countries studied make greater efforts to improve these critical practices in order to reduce child morbidity and mortality in the West Africa sub-region. Intervention studies on complementary feeding should target those socio-demographic factors that pose risks to optimal complementary feeding.

  1. Assessing climate adaptation options and uncertainties for cereal systems in West Africa

    NASA Astrophysics Data System (ADS)

    Guan, K.; Sultan, B.; Biasutti, M.; Lobell, D. B.

    2015-12-01

    The already fragile agriculture production system in West Africa faces further challenges in meeting food security in the coming decades, primarily due to a fast increasing population and risks of climate change. Successful adaptation of agriculture should not only benefit in the current climate but should also reduce negative (or enhance positive) impacts for climate change. Assessment of various possible adaptation options and their uncertainties provides key information for prioritizing adaptation investments. Here, based on the several robust aspects of climate projections in this region (i.e. temperature increases and rainfall pattern shifts), we use two well-validated crop models (i.e. APSIM and SARRA-H) and an ensemble of downscaled climate forcing to assess five possible and realistic adaptation options (late sowing, intensification, thermal time increase, water harvesting and increased resilience to heat stress) in West Africa for the staple crop production of sorghum. We adopt a new assessment framework to account for both the impacts of adaptation options in current climate and their ability to reduce impacts of future climate change, and also consider changes in both mean yield and its variability. Our results reveal that most proposed "adaptation options" are not more beneficial in the future than in the current climate, i.e. not really reduce the climate change impacts. Increased temperature resilience during grain number formation period is the main adaptation that emerges. We also find that changing from the traditional to modern cultivar, and later sowing in West Sahel appear to be robust adaptations.

  2. Ciguatera fish poisoning on the West Africa Coast: An emerging risk in the Canary Islands (Spain).

    PubMed

    Boada, Luis D; Zumbado, Manuel; Luzardo, Octavio P; Almeida-González, Maira; Plakas, Steven M; Granade, Hudson R; Abraham, Ann; Jester, Edward L E; Dickey, Robert W

    2010-12-01

    Ciguatera fish poisoning (CFP) is endemic in certain tropical and subtropical regions of the world. CFP had not been described on the West Africa Coast until a 2004 outbreak in the Canary Islands. In 2008-2009, two additional outbreaks of ciguatera occurred. Individuals afflicted had consumed lesser amberjack (Seriola rivoliana) captured from nearby waters. Caribbean ciguatoxin-1 (C-CTX-1) was confirmed in fish samples by LC-MS/MS. Ciguatoxic fish in this region may pose a new health risk for the seafood consumer.

  3. Continued transmission of Zika virus in humans in West Africa, 1992-2016.

    PubMed

    Herrera, Bobby Brooke; Chang, Charlotte A; Hamel, Donald J; Mboup, Souleymane; Ndiaye, Daouda; Imade, Godwin; Okpokwu, Jonathan; Agbaji, Oche; Bei, Amy K; Kanki, Phyllis J

    2017-04-08

    First identified in 1947 in Uganda, Zika virus (ZIKV) has remained largely unstudied until the recent outbreak in Latin America. This study aimed to measure the prevalence of ZIKV in febrile patients in Senegal and Nigeria in samples collected from 1992-2016. The seroprevalence of ZIKV was 6.2% based on ZIKV IgM and negative for dengue reactivity. ZIKV envelope (E) was amplified from 4 samples. Phylogenetic analysis showed that the ZIKVs belonged to the African lineage, grouping with either the Nigerian or MR766 sub-lineages. This study provides evidence that ZIKV has been silently circulating in West Africa for two decades.

  4. Cost-effectiveness analysis of malaria chemoprophylaxis for travellers to West-Africa

    PubMed Central

    2010-01-01

    Background The importation of malaria to non-endemic countries remains a major cause of travel-related morbidity and a leading cause of travel-related hospitalizations. Currently they are three priority medications for malaria prophylaxis to West Africa: mefloquine, atovaquone/proguanil and doxycycline. We investigate the cost effectiveness of a partial reimbursement of the cheapest effective malaria chemoprophylaxis (mefloquine) for travellers to high risk areas of malaria transmission compared with the current situation of no reimbursement. Methods This study is a cost-effectiveness analysis based on malaria cases imported from West Africa to Switzerland from the perspective of the Swiss health system. We used a decision tree model and made a literature research on the components of travel related malaria. The main outcome measure was the cost effectiveness of malaria chemoprophylaxis reimbursement based on malaria and deaths averted. Results Using a program where travellers would be reimbursed for 80% of the cost of the cheapest malaria chemoprophylaxis is dominant (i.e. cost saving and more effective than the current situation) using the assumption that currently 68.7% of travellers to West Africa use malaria chemoprophylaxis. If the current usage of malaria chemoprophylaxis would be higher, 82.4%, the incremental cost per malaria case averted is € 2'302. The incremental cost of malaria death averted is € 191'833. The most important factors influencing the model were: the proportion of travellers using malaria chemoprophylaxis, the probability of contracting malaria without malaria chemoprophylaxis, the cost of the mefloquine regimen, the decrease in the number of travellers without malaria chemoprophylaxis in the reimbursement strategy. Conclusions This study suggests that a reimbursement of 80% of the cost of the cheapest effective malaria chemoprophylaxis (mefloquine) for travellers from Switzerland to West Africa is highly effective in terms of malaria

  5. Agriculture in West Africa in the Twenty-First Century: Climate Change and Impacts Scenarios, and Potential for Adaptation.

    PubMed

    Sultan, Benjamin; Gaetani, Marco

    2016-01-01

    West Africa is known to be particularly vulnerable to climate change due to high climate variability, high reliance on rain-fed agriculture, and limited economic and institutional capacity to respond to climate variability and change. In this context, better knowledge of how climate will change in West Africa and how such changes will impact crop productivity is crucial to inform policies that may counteract the adverse effects. This review paper provides a comprehensive overview of climate change impacts on agriculture in West Africa based on the recent scientific literature. West Africa is nowadays experiencing a rapid climate change, characterized by a widespread warming, a recovery of the monsoonal precipitation, and an increase in the occurrence of climate extremes. The observed climate tendencies are also projected to continue in the twenty-first century under moderate and high emission scenarios, although large uncertainties still affect simulations of the future West African climate, especially regarding the summer precipitation. However, despite diverging future projections of the monsoonal rainfall, which is essential for rain-fed agriculture, a robust evidence of yield loss in West Africa emerges. This yield loss is mainly driven by increased mean temperature while potential wetter or drier conditions as well as elevated CO2 concentrations can modulate this effect. Potential for adaptation is illustrated for major crops in West Africa through a selection of studies based on process-based crop models to adjust cropping systems (change in varieties, sowing dates and density, irrigation, fertilizer management) to future climate. Results of the cited studies are crop and region specific and no clear conclusions can be made regarding the most effective adaptation options. Further efforts are needed to improve modeling of the monsoon system and to better quantify the uncertainty in its changes under a warmer climate, in the response of the crops to such

  6. Agriculture in West Africa in the Twenty-First Century: Climate Change and Impacts Scenarios, and Potential for Adaptation

    PubMed Central

    Sultan, Benjamin; Gaetani, Marco

    2016-01-01

    West Africa is known to be particularly vulnerable to climate change due to high climate variability, high reliance on rain-fed agriculture, and limited economic and institutional capacity to respond to climate variability and change. In this context, better knowledge of how climate will change in West Africa and how such changes will impact crop productivity is crucial to inform policies that may counteract the adverse effects. This review paper provides a comprehensive overview of climate change impacts on agriculture in West Africa based on the recent scientific literature. West Africa is nowadays experiencing a rapid climate change, characterized by a widespread warming, a recovery of the monsoonal precipitation, and an increase in the occurrence of climate extremes. The observed climate tendencies are also projected to continue in the twenty-first century under moderate and high emission scenarios, although large uncertainties still affect simulations of the future West African climate, especially regarding the summer precipitation. However, despite diverging future projections of the monsoonal rainfall, which is essential for rain-fed agriculture, a robust evidence of yield loss in West Africa emerges. This yield loss is mainly driven by increased mean temperature while potential wetter or drier conditions as well as elevated CO2 concentrations can modulate this effect. Potential for adaptation is illustrated for major crops in West Africa through a selection of studies based on process-based crop models to adjust cropping systems (change in varieties, sowing dates and density, irrigation, fertilizer management) to future climate. Results of the cited studies are crop and region specific and no clear conclusions can be made regarding the most effective adaptation options. Further efforts are needed to improve modeling of the monsoon system and to better quantify the uncertainty in its changes under a warmer climate, in the response of the crops to such

  7. Genetic diversity of newcastle disease virus in wild birds and pigeons in West Africa.

    PubMed

    Snoeck, Chantal J; Adeyanju, Adeniyi T; Owoade, Ademola A; Couacy-Hymann, Emmanuel; Alkali, Bello R; Ottosson, Ulf; Muller, Claude P

    2013-12-01

    In West and Central Africa, virulent Newcastle disease virus (NDV) strains of the recently identified genotypes XIV, XVII, and XVIII are enzootic in poultry, representing a considerable threat to the sector. The increasing number of reports of virulent strains in wild birds at least in other parts of the world raised the question of a potential role of wild birds in the spread of virulent NDV in sub-Saharan Africa as well. We investigated 1,723 asymptomatic birds sampled at live-bird markets and sites important for wild-bird conservation in Nigeria and 19 sick or dead wild birds in Côte d'Ivoire for NDV class I and II. Typical avirulent wild-type genotype I strains were found in wild waterfowl in wetlands in northeastern Nigeria. They were unrelated to vaccine strains, and the involvement of inter- or intracontinental migratory birds in their circulation in the region is suggested. Phylogenetic analyses also revealed that genotype VI strains found in pigeons, including some putative new subgenotype VIh and VIi strains, were introduced on multiple separate occasions in Nigeria. A single virulent genotype XVIII strain was found in a dead wild bird in Côte d'Ivoire, probably as a result of spillover from sick poultry. In conclusion, screening of wild birds and pigeons for NDV revealed the presence a variety of virulent and avirulent strains in West Africa but did not provide strong evidence that wild birds play an important role in the spread of virulent strains in the region.

  8. Genetic Diversity of Newcastle Disease Virus in Wild Birds and Pigeons in West Africa

    PubMed Central

    Snoeck, Chantal J.; Adeyanju, Adeniyi T.; Owoade, Ademola A.; Couacy-Hymann, Emmanuel; Alkali, Bello R.; Ottosson, Ulf

    2013-01-01

    In West and Central Africa, virulent Newcastle disease virus (NDV) strains of the recently identified genotypes XIV, XVII, and XVIII are enzootic in poultry, representing a considerable threat to the sector. The increasing number of reports of virulent strains in wild birds at least in other parts of the world raised the question of a potential role of wild birds in the spread of virulent NDV in sub-Saharan Africa as well. We investigated 1,723 asymptomatic birds sampled at live-bird markets and sites important for wild-bird conservation in Nigeria and 19 sick or dead wild birds in Côte d'Ivoire for NDV class I and II. Typical avirulent wild-type genotype I strains were found in wild waterfowl in wetlands in northeastern Nigeria. They were unrelated to vaccine strains, and the involvement of inter- or intracontinental migratory birds in their circulation in the region is suggested. Phylogenetic analyses also revealed that genotype VI strains found in pigeons, including some putative new subgenotype VIh and VIi strains, were introduced on multiple separate occasions in Nigeria. A single virulent genotype XVIII strain was found in a dead wild bird in Côte d'Ivoire, probably as a result of spillover from sick poultry. In conclusion, screening of wild birds and pigeons for NDV revealed the presence a variety of virulent and avirulent strains in West Africa but did not provide strong evidence that wild birds play an important role in the spread of virulent strains in the region. PMID:24123735

  9. Identifying the pattern of molecular evolution for Zaire ebolavirus in the 2014 outbreak in West Africa.

    PubMed

    Liu, Si-Qing; Deng, Cheng-Lin; Yuan, Zhi-Ming; Rayner, Simon; Zhang, Bo

    2015-06-01

    The current Ebola virus disease (EVD) epidemic has killed more than all previous Ebola outbreaks combined and, even as efforts appear to be bringing the outbreak under control, the threat of reemergence remains. The availability of new whole-genome sequences from West Africa in 2014 outbreak, together with those from the earlier outbreaks, provide an opportunity to investigate the genetic characteristics, the epidemiological dynamics and the evolutionary history for Zaire ebolavirus (ZEBOV). To investigate the evolutionary properties of ZEBOV in this outbreak, we examined amino acid mutations, positive selection, and evolutionary rates on the basis of 123 ZEBOV genome sequences. The estimated phylogenetic relationships within ZEBOV revealed that viral sequences from the same period or location formed a distinct cluster. The West Africa viruses probably derived from Middle Africa, consistent with results from previous studies. Analysis of the seven protein regions of ZEBOV revealed evidence of positive selection acting on the GP and L genes. Interestingly, all putatively positive-selected sites identified in the GP are located within the mucin-like domain of the solved structure of the protein, suggesting a possible role in the immune evasion properties of ZEBOV. Compared with earlier outbreaks, the evolutionary rate of GP gene was estimated to significantly accelerate in the 2014 outbreak, suggesting that more ZEBOV variants are generated for human to human transmission during this sweeping epidemic. However, a more balanced sample set and next generation sequencing datasets would help achieve a clearer understanding at the genetic level of how the virus is evolving and adapting to new conditions.

  10. West Africa

    Atmospheric Science Data Center

    2013-04-16

    ... (MISR) illustrate the abundance of atmospheric particulate matter across the region. The left-hand panels are natural-color views from ... across the region is noticeable. The distinctive area of dark green vegetation (apparent below and left of image center) are situated in ...

  11. Robust features of future climate change impacts on sorghum yields in West Africa

    NASA Astrophysics Data System (ADS)

    Sultan, B.; Guan, K.; Kouressy, M.; Biasutti, M.; Piani, C.; Hammer, G. L.; McLean, G.; Lobell, D. B.

    2014-10-01

    West Africa is highly vulnerable to climate hazards and better quantification and understanding of the impact of climate change on crop yields are urgently needed. Here we provide an assessment of near-term climate change impacts on sorghum yields in West Africa and account for uncertainties both in future climate scenarios and in crop models. Towards this goal, we use simulations of nine bias-corrected CMIP5 climate models and two crop models (SARRA-H and APSIM) to evaluate the robustness of projected crop yield impacts in this area. In broad agreement with the full CMIP5 ensemble, our subset of bias-corrected climate models projects a mean warming of +2.8 °C in the decades of 2031-2060 compared to a baseline of 1961-1990 and a robust change in rainfall in West Africa with less rain in the Western part of the Sahel (Senegal, South-West Mali) and more rain in Central Sahel (Burkina Faso, South-West Niger). Projected rainfall deficits are concentrated in early monsoon season in the Western part of the Sahel while positive rainfall changes are found in late monsoon season all over the Sahel, suggesting a shift in the seasonality of the monsoon. In response to such climate change, but without accounting for direct crop responses to CO2, mean crop yield decreases by about 16-20% and year-to-year variability increases in the Western part of the Sahel, while the eastern domain sees much milder impacts. Such differences in climate and impacts projections between the Western and Eastern parts of the Sahel are highly consistent across the climate and crop models used in this study. We investigate the robustness of impacts for different choices of cultivars, nutrient treatments, and crop responses to CO2. Adverse impacts on mean yield and yield variability are lowest for modern cultivars, as their short and nearly fixed growth cycle appears to be more resilient to the seasonality shift of the monsoon, thus suggesting shorter season varieties could be considered a potential

  12. The DACCIWA Project: Dynamics-Aerosol-Chemistry-Cloud interactions in West Africa

    NASA Astrophysics Data System (ADS)

    Knippertz, Peter

    2014-05-01

    Massive economic and population growth and urbanisation are expected to lead to a tripling of anthropogenic emissions from southern West Africa (SWA) between 2000 and 2030, the impacts of which on human health, ecosystems, food security and the regional climate are largely unknown. An assessment of these impacts is complicated by (a) a superposition with effects of global climate change, (b) the strong dependence of SWA on the sensitive West African monsoon, (c) incomplete scientific understanding of interactions between emissions, clouds, radiation, precipitation and regional circulations and (d) by a lack of observations to advance our understanding and improve predictions. The purpose of this contribution is to introduce the research consortium DACCIWA (Dynamics-Aerosol-Chemistry-Cloud interactions in West Africa), which comprises 16 partners in six European and West African countries. The interdisciplinary DACCIWA team will build on the scientific and logistical foundations established by the African Monsoon Multidisciplinary Analysis (AMMA) project and collaborate closely with operational centres. DACCIWA will receive funding of about M8.75€ from the European Commission as part of Framework Programme 7 from 2015 until 2018. The DACCIWA project will conduct extensive fieldwork in SWA to collect high-quality observations, spanning the entire process chain from surface-based natural and anthropogenic emissions to impacts on health, ecosystems and climate. This will include a major field campaign in summer 2015 with three research aircrafts and two ground-based supersites. Combining the resulting benchmark dataset with a wide range of modelling activities will allow us: (a) to assess all relevant physical and chemical processes, (b) to improve the monitoring of climate and compositional parameters from space, (c) to determine health impacts from air pollution, and (d) to develop the next generation of weather and climate models capable of representing coupled

  13. Clinical manifestations of Waardenburg syndrome in a male adolescent in Mali, West Africa.

    PubMed

    Imperato, Pascal James; Imperato, Gavin H

    2015-02-01

    Waardenburg syndrome (WS) is a genetic disorder of which there are four distinct types. These four types are differentiated by the physical defects which they produce. Presented here is the case of a 13-year-old boy with WS Type I who was observed and physically assessed in Mali, West Africa in 1969. His physical findings included a bright blue coloring to the irises of the eyes, profound sensorineural deafness, mutism, dystopia canthorum (lateral displacement of the inner canthi of the eyes), broad nasal root, bushy eyebrows, and scaphoid deformities of the supraorbital portions of the frontal bone. Because family members were not available for interviews or physical examinations, it was not possible to determine if this patient was suffering from a congenital form of the disorder or from a spontaneous mutation. Given the patient's then location in a remote rural area of Mali where electricity was absent, it was not possible to perform additional diagnostic tests. The patient described here is the first with WS in Mali, West Africa to have been medically observed and evaluated and later documented in the medical literature. A second case of the syndrome in Mali was described in the medical literature in 2011 in an 18-month-old infant who did not have sensorineural hearing loss, but who did have a bilateral cleft lip. An historical overview of WS is presented along with details concerning the characteristics of the four types of the disorder.

  14. Genetic and linguistic affinities between human populations in Eurasia and West Africa.

    PubMed

    Nettle, Daniel; Harriss, Louise

    2003-06-01

    This study examines the relationship between genetic distance and linguistic affiliation for five regional sets of populations from Eurasia and West Africa. Human genetic and linguistic diversity have been proposed to be generally correlated, either through a direct link, whereby linguistic and genetic affiliations reflect the same past population processes, or an indirect one, where the evolution of the two types of diversity is independent but conditioned by the same geographical factors. By controlling for proximity, indirect correlations due to common geography are eliminated, and any residual relationships found are likely to reflect common linguistic-genetic processes. Clear relationships between genetic distances and linguistic relatedness are detectable in Europe and East and Central Asia, but not in the Middle East, Southeast Asia, or West Africa. We suggest that linguistic and genetic affiliations will only be correlated under specific conditions, such as where there have been large-scale demic diffusions in the last few thousand years, and relative sedentism in the subsequent period.

  15. Topical application of diethylcarbamazine to detect onchocerciasis recrudescence in west Africa.

    PubMed

    Toè, L; Adjami, A G; Boatin, B A; Back, C; Alley, E S; Dembélé, N; Brika, P G; Pearlman, E; Unnasch, T R

    2000-01-01

    The Onchocerciasis Control Programme in West Africa (OCP) has succeeded in eliminating blinding onchocerciasis as a public health problem throughout much of West Africa. The efforts of the OCP are now turning towards surveillance, with the goal of rapidly detecting and controlling outbreaks of infection in the onchocerciasis-free zone. With this goal in mind, cutaneous application of a solution of diethylcarbamazine (the DEC-patch test) was evaluated in 1996-99 as a method to detect patent Onchocerca volvulus infection in children and adolescents, a sentinel population for the detection of recrudescence. In an analysis of 1887 individuals in Côte d'Ivoire and Burkina Faso, the DEC-patch test produced prevalence estimates comparable to those obtained by skin snip. The sensitivity of the DEC-patch assay was marginally greater in children and adolescents than in adults, and was greater in individuals who had received prior Mectizan treatment. These data suggest that the DEC-patch test may be a useful tool for detecting recrudescence of O. volvulus infection in a sentinel population of children and young adults within the onchocerciasis-free zone created by the OCP.

  16. The Cuban Response to the Ebola Epidemic in West Africa: Lessons in Solidarity.

    PubMed

    Chaple, Enrique Beldarraín; Mercer, Mary Anne

    2017-01-01

    In December 2013 the first case of Ebola appeared in Guinea. In September 2014 the United Nations (UN) and its specialized agency the World Health Organization (WHO) issued a call for medical collaboration in response to the medical crisis and social disaster caused by the Ebola virus epidemic in West Africa. Cuban authorities responded immediately to the call by offering specialized help for the epidemic, in collaboration with WHO. A group of 256 Cuban doctors, nurses and other health professionals provided direct care during the Ebola epidemic in Sierra Leone, Liberia and Equatorial Guinea from October 2014 to April 2015. This paper explains the main features of the Cuban health system, describes the development of Cuba's international medical cooperation approach, and highlights the work done by Cuban health collaborators in addressing the damage caused by the Ebola epidemic. Information used includes reports and documents of the Ministry of Public Health of Cuba, reports of WHO and PAHO, and articles published in scientific journals and newspaper articles. The response of the Cuban medical teams to the Ebola epidemic in West Africa is only one example of the Cuban efforts to strengthening health care provision in areas of need throughout the world.

  17. Gravity-driven structures and rift basin evolution: Rio Muni Basin, offshore equatorial West Africa

    SciTech Connect

    Turner, J.P.

    1995-08-01

    Offshore Equatorial Guinea, west Africa, gravity-driven nappes, more than 1 km thick and 15 km from head to toe, provide key evidence in reconstructing the late synrift: evolution of this part of the South Atlantic margin basin system. Furthermore, Aptian-Cenomanian carbonate and clastic rocks in the nappes` allochthonous hanging walls are attracting interest as a new exploration play in west Africa. The nappes exhibit a range of geometries that suggest they share many of the same deformation processes as thin-skin thrust and linked extensional fault systems. Not only are these structures significant in their own right, representing a rare example of gravity tectonics in the virtual absence of major halokinesis, but their presence may record an other-wise undetectable process active during the transition from a rift basin to a passive continental margin. A review of Equatorial Guinea in its pre-Atlantic configuration, alongside neighboring basins in Brazil (the Sergipe-Alagoas basin) and Gabon, suggests that gravity gliding was sustained by a relatively steep, westward paleoslope promoted by east-ward offset of the locus of thermal uplift from the rift basin (i.e., a simple shear model of basin formation). In contrast to gravity-driven structures in most postrift settings, the Equatorial Guinea nappes developed at the close of the Aptian-Albian synrift episode in response to a growing bathymetric deep caused by rapid subsidence outpacing restricted sedimentation.

  18. Viral bioterrorism: Learning the lesson of Ebola virus in West Africa 2013-2015.

    PubMed

    Cenciarelli, Orlando; Gabbarini, Valentina; Pietropaoli, Stefano; Malizia, Andrea; Tamburrini, Annalaura; Ludovici, Gian Marco; Carestia, Mariachiara; Di Giovanni, Daniele; Sassolini, Alessandro; Palombi, Leonardo; Bellecci, Carlo; Gaudio, Pasquale

    2015-12-02

    Among the potential biological agents suitable as a weapon, Ebola virus represents a major concern. Classified by the CDC as a category A biological agent, Ebola virus causes severe hemorrhagic fever, characterized by high case-fatality rate; to date, no vaccine or approved therapy is available. The EVD epidemic, which broke out in West Africa since the late 2013, has got the issue of the possible use of Ebola virus as biological warfare agent (BWA) to come to the fore once again. In fact, due to its high case-fatality rate, population currently associates this pathogen to a real and tangible threat. Therefore, its use as biological agent by terrorist groups with offensive purpose could have serious repercussions from a psychosocial point of view as well as on closely sanitary level. In this paper, after an initial study of the main characteristics of Ebola virus, its potential as a BWA was evaluated. Furthermore, given the spread of the epidemic in West Africa in 2014 and 2015, the potential dissemination of the virus from an urban setting was evaluated. Finally, it was considered the actual possibility to use this agent as BWA in different scenarios, and the potential effects on one or more nation's stability.

  19. Neogene cratonic erosion fluxes and landform evolution processes from regional regolith mapping (Burkina Faso, West Africa)

    NASA Astrophysics Data System (ADS)

    Grimaud, Jean-Louis; Chardon, Dominique; Metelka, Václav; Beauvais, Anicet; Bamba, Ousmane

    2015-07-01

    The regionally correlated and dated regolith-paleolandform sequence of Sub-Saharan West Africa offers a unique opportunity to constrain continental-scale regolith dynamics as the key part of the sediment routing system. In this study, a regolith mapping protocol is developed and applied at the scale of Southwestern Burkina Faso. Mapping combines field survey and remote sensing data to reconstruct the topography of the last pediplain that formed over West Africa in the Early and Mid-Miocene (24-11 Ma). The nature and preservation pattern of the pediplain are controlled by the spatial variation of bedrock lithology and are partitioned among large drainage basins. Quantification of pediplain dissection and drainage growth allows definition of a cratonic background denudation rate of 2 m/My and a minimum characteristic timescale of 20 Ma for shield resurfacing. These results may be used to simulate minimum export fluxes of drainage basins of constrained size over geological timescales. Background cratonic denudation results in a clastic export flux of ~ 4 t/km2/year, which is limited by low denudation efficiency of slope processes and correlatively high regolith storage capacity of tropical shields. These salient characteristics of shields' surface dynamics would tend to smooth the riverine export fluxes of shields through geological time.

  20. Establishment of a General Medicine Residency Training Program in Rural West Africa

    PubMed Central

    Drislane, Frank W.; Akpalu, Albert; Wegdam, Harry H.J.

    2014-01-01

    Ghana, a developing country in West Africa, has major medical burdens in taking care of a large population with limited resources. Its three medical schools produce more than 200 graduates per year, but most emigrate to developed lands after training. Ghana is working to educate and retain locally trained physicians, but it is difficult to get them to work in rural settings where the need is greatest. This article details the establishment of a General Medicine residency at a 150-bed hospital in rural Ghana. Early training comprises 6 months each in Medicine, Surgery, OB/GYN, and Pediatrics; the hospital in Techiman also has a Surgery residency. House officers choose the program for more hands-on experience than they can get in larger centers. They perform many tasks, including surgery, sooner and more independently than do residents in developed countries. The training program includes a morning report, clinical teaching rounds, and rotations on in-patient wards and in the Emergency Department and clinics. Teaching focuses on history, physical examination, good communication, and proper follow-up, with rigorous training in the OR and some clinical research projects pertinent to Ghana. Trainees work hard and learn from one another, from a dedicated faculty, and by evaluating and treating very sick patients. Ghana’s rural residencies offer rigorous and attractive training, but it is too soon to tell whether this will help stem the “brain drain” of young physicians out of West Africa. PMID:25191148

  1. Mechanisms Linking Land Use and Regional Climate Changes in West Africa

    NASA Astrophysics Data System (ADS)

    Wang, G.; Ahmed, K. F.; Yu, M.; JI, Z.; Pal, J. S.

    2014-12-01

    Land use land cover change is an important driver for regional climate changes in West Africa due to the strong land-atmosphere coupling. On the other hand, land use is also strongly influenced by climate changes due to the primarily rain-fed agriculture in this region and the relatively low capacity to adapt. It is therefore important that projections for future climate changes or land use changes account for the impact of the feedback between land use and climate. Land use influences regional climate through several different pathways, including changes in surface biogeophysical properties (e.g., surface albedo, Bowen ratio, surface roughness) that have been widely studied, and changes in the dynamic properties of the land surface influencing dust emission. The relative importance of these two pathways is likely to be model dependent and region dependent. In this study the effects of these two pathways will be evaluated and compared, based on results from a modeling framework that includes a regional climate-vegetation model, a crop growth model, an agricultural economics model, and a land use allocation model. This will be conducted in the context of future land use and climate change projections, with the ultimate objective to assess how agricultural land use in West Africa may change driven by climate and socioeconomic changes, and how the resulting land use change may further modify regional climate in the future.

  2. Nocturnal low-level clouds over southern West Africa analysed using high-resolution simulations

    NASA Astrophysics Data System (ADS)

    Adler, Bianca; Kalthoff, Norbert; Gantner, Leonhard

    2017-01-01

    We performed a high-resolution numerical simulation to study the development of extensive low-level clouds that frequently form over southern West Africa during the monsoon season. This study was made in preparation for a field campaign in 2016 within the Dynamics-aerosol-chemistry-cloud interactions in West Africa (DACCIWA) project and focuses on an area around the city of Savè in southern Benin. Nocturnal low-level clouds evolve a few hundred metres above the ground around the same level as a distinct low-level jet. Several processes are found to determine the spatio-temporal evolution of these clouds including (i) significant cooling of the nocturnal atmosphere caused by horizontal advection with the south-westerly monsoon flow during the first half of the night, (ii) vertical cold air advection due to gravity waves leading to clouds in the wave crests and (iii) enhanced convergence and upward motion upstream of existing clouds that trigger new clouds. The latter is caused by an upward shift of the low-level jet in cloudy areas leading to horizontal convergence in the lower part and to horizontal divergence in the upper part of the cloud layer. Although this single case study hardly allows for a generalisation of the processes found, the results added to the optimisation of the measurements strategy for the field campaign and the observations will be used to test the hypotheses for cloud formation resulting from this study.

  3. Calibration and uncertainty issues of a hydrological model (SWAT) applied to West Africa

    NASA Astrophysics Data System (ADS)

    Schuol, J.; Abbaspour, K. C.

    2006-09-01

    Distributed hydrological models like SWAT (Soil and Water Assessment Tool) are often highly over-parameterized, making parameter specification and parameter estimation inevitable steps in model calibration. Manual calibration is almost infeasible due to the complexity of large-scale models with many objectives. Therefore we used a multi-site semi-automated inverse modelling routine (SUFI-2) for calibration and uncertainty analysis. Nevertheless, the question of when a model is sufficiently calibrated remains open, and requires a project dependent definition. Due to the non-uniqueness of effective parameter sets, parameter calibration and prediction uncertainty of a model are intimately related. We address some calibration and uncertainty issues using SWAT to model a four million km2 area in West Africa, including mainly the basins of the river Niger, Volta and Senegal. This model is a case study in a larger project with the goal of quantifying the amount of global country-based available freshwater. Annual and monthly simulations with the "calibrated" model for West Africa show promising results in respect of the freshwater quantification but also point out the importance of evaluating the conceptual model uncertainty as well as the parameter uncertainty.

  4. Summer Synoptic-Scale Waves over Tropical West Africa Observed by TRMM

    NASA Technical Reports Server (NTRS)

    Starr, David O. (Technical Monitor); Gu, Guojun; Adler, Robert F.; Huffman, George J.; Curtis, Scott

    2003-01-01

    A 5-year daily rainfall dataset (3B42) from TRMM (Tropical Rainfall Measuring Mission) is used to investigate the activity and properties of westward-propagating synoptic-scale waves over tropical West Africa. Evident wave signals appearing in wavenumber-frequency space show their modulations on the surface rainfall pattern during the boreal summer. Interannual variability exists in both their intensity and spectral properties, i. e., dominant frequency and wavenumber ranges. These variabilities can be partly ascribed to year-to-year variations of their embedded large-scale environment, especially the status of mid-tropospheric African easterly jet (AEJ). Generally, a stronger (weaker) AEJ indicates more (less) instability energy yielding a stronger (weaker) wave activity season. Seasonal mean rainfall has shown an impact on these waves in some years. However, the impact is not as clear and consistent as AEJ, implying the complexity of their relationship with large-scale environment. To fully understand interannual variability of synoptic-scale waves over tropical West Africa, including the variability in their preferred frequencies and wavenumbers, it is therefore necessary to examine possible intra-seasonal variations existing in both wave activity and large-scale fields, in addition to their structure, propagation, and associated convection.

  5. On the politics and practice of Muslim fertility: comparative evidence from West Africa.

    PubMed

    Johnson-Hanks, Jennifer

    2006-03-01

    Recent popular works have represented Muslim fertility as dangerously high, both a cause and consequence of religious fundamentalism. This article uses comparative, statistical methods to show that this representation is empirically wrong, at least in West Africa. Although religion strongly inflects reproductive practice, its effects are not constant across different communities. In West African countries with Muslim majorities, Muslim fertility is lower than that of their non-Muslim conationals; in countries where Muslims are in the minority, their apparently higher reproductive rates converge to those of the majority when levels of education and urban residence are taken into account. A similar pattern holds for infant mortality. By contrast, in all seven countries, Muslim women are more likely to report that their most recent child was wanted. The article concludes with a discussion of the relationship between autonomy and fertility desires.

  6. First report of sylvatic DENV-2-associated dengue hemorrhagic fever in West Africa.

    PubMed

    Franco, Leticia; Palacios, Gustavo; Martinez, José Antonio; Vázquez, Ana; Savji, Nazir; De Ory, Fernando; Sanchez-Seco, María Paz; Martín, Dolores; Lipkin, W Ian; Tenorio, Antonio

    2011-08-01

    Dengue virus (DENV) circulates in human and sylvatic cycles. Sylvatic strains are both ecologically and evolutionarily distinct from endemic viruses. Although sylvatic dengue cycles occur in West African countries and Malaysia, only a few cases of mild human disease caused by sylvatic strains and one single case of dengue hemorrhagic fever in Malaysia have been reported. Here we report a case of dengue hemorrhagic fever (DHF) with thrombocytopenia (13000/µl), a raised hematocrit (32% above baseline) and mucosal bleeding in a 27-year-old male returning to Spain in November 2009 after visiting his home country Guinea Bissau. Sylvatic DENV-2 West African lineage was isolated from blood and sera. This is the first case of DHF associated with sylvatic DENV-2 in Africa and the second case worldwide of DHF caused by a sylvatic strain.

  7. Radar altimetry backscattering signatures at Ka, Ku, C, and S bands over West Africa

    NASA Astrophysics Data System (ADS)

    Frappart, F.; Fatras, C.; Mougin, E.; Marieu, V.; Diepkilé, A. T.; Blarel, F.; Borderies, P.

    This study presents a comprehensive comparison of radar altimetry signatures at Ka-, Ku-, C-, and S-bands using SARAL, ENVISAT and Jason-2 data over the major bioclimatic zones, soil and vegetation types encountered in West-Africa, with an emphasis on the new information at Ka-band provided by the recently launched SARAL-Altika mission. Spatio-temporal variations of the radar altimetry responses were related to changes in surface roughness, land cover and soil wetness. Analysis of time series of backscattering coefficients along the West African bioclimatic gradient shows that radar echoes at nadir incidence are well correlated to soil moisture in semi-arid savannah environments. Radar altimeters are able to detect the presence of water even under a dense canopy cover at all frequencies. But only measurements at Ka-band are able to penetrate underneath the canopy of non-inundated tropical evergreen forests.

  8. The 1 Ma Lake Bosumtwi (West Africa) Paleoclimate Record: Comparisons to Marine and Polar Records

    NASA Astrophysics Data System (ADS)

    Peck, J. A.; Shanahan, T. M.; King, J. W.; Overpeck, J. T.; Scholz, C. A.; Heil, C.; Forman, S. L.; Amoako, P. Y.

    2007-12-01

    Lake Bosumtwi is a hydrologically closed lake occupying a 1.07 Ma impact crater in Ghana, West Africa. The lake lies beneath the path of the seasonal migration of the ITCZ and therefore can provide a sedimentary record of monsoon variability in West Africa. Scientific drilling recovered a 291-m long sediment section that spans the full 1 Ma history of the lake. This long continental record is ideal for comparison to long marine and ice-core records at both glacial-interglacial and abrupt-change timescales. Oxygen-isotope stratigraphy, derived from calcareous fossils, often provides age control and a way to place individual marine sediment cores into a global stratigraphic framework. Lacking a direct tie-in to the marine oxygen-isotope stratigraphy, individual lacustrine basins can present challenges for global correlation. Through radiocarbon, optically stimulated luminescence and paleomagnetic dating, limited age control has been established for the 1 Ma Lake Bosumtwi sediment sequence. Within a Bosumtwi sediment sequence that is mostly laminated occur intervals of non-laminated sediment having increased density, decreased organic content and a high-coercivity magnetic mineral assemblage. Some of these massive layers contain slump-folding and intraformational clasts. These lithologies are interpreted to represent lake-level lowstands when a diminished West African summer monsoon resulted in decreased moisture balance and lake-level regression. Some Bosumtwi lake-level lowstands match intervals of increased sea surface salinity in the Gulf of Guinea resulting from reduced river discharge (Weldeab et al. 2007, Science, 316, 1303-1307). However, during other intervals (MIS2) there are differences between the two records. Corresponding to glacial stages and stadials, increased amounts of high-coercivity magnetic minerals are present in the Lake Bosumtwi sediment. Elevated aerosol dust export from arid Sahel sources, possibly accompanied by enhanced magnetic

  9. Male Circumcision and the Epidemic Emergence of HIV-2 in West Africa

    PubMed Central

    Hewlett, Barry Stephen; Camacho, Ricardo Jorge

    2016-01-01

    Background Epidemic HIV-2 (groups A and B) emerged in humans circa 1930–40. Its closest ancestors are SIVsmm infecting sooty mangabeys from southwestern Côte d'Ivoire. The earliest large-scale serological surveys of HIV-2 in West Africa (1985–91) show a patchy spread. Côte d'Ivoire and Guinea-Bissau had the highest prevalence rates by then, and phylogeographical analysis suggests they were the earliest epicenters. Wars and parenteral transmission have been hypothesized to have promoted HIV-2 spread. Male circumcision (MC) is known to correlate negatively with HIV-1 prevalence in Africa, but studies examining this issue for HIV-2 are lacking. Methods We reviewed published HIV-2 serosurveys for 30 cities of all West African countries and obtained credible estimates of real prevalence through Bayesian estimation. We estimated past MC rates of 218 West African ethnic groups, based on ethnographic literature and fieldwork. We collected demographic tables specifying the ethnic partition in cities. Uncertainty was incorporated by defining plausible ranges of parameters (e.g. timing of introduction, proportion circumcised). We generated 1,000 sets of past MC rates per city using Latin Hypercube Sampling with different parameter combinations, and explored the correlation between HIV-2 prevalence and estimated MC rate (both logit-transformed) in the 1,000 replicates. Results and Conclusions Our survey reveals that, in the early 20th century, MC was far less common and geographically more variable than nowadays. HIV-2 prevalence in 1985–91 and MC rates in 1950 were negatively correlated (Spearman rho = -0.546, IQR: -0.553–-0.546, p≤0.0021). Guinea-Bissau and Côte d'Ivoire cities had markedly lower MC rates. In addition, MC was uncommon in rural southwestern Côte d'Ivoire in 1930.The differential HIV-2 spread in West Africa correlates with different historical MC rates. We suggest HIV-2 only formed early substantial foci in cities with substantial uncircumcised

  10. Modes, tempo and spatial variability of Cenozoic cratonic denudation: morphoclimatic constraints from West Africa

    NASA Astrophysics Data System (ADS)

    Beauvais, Anicet; Chardon, Dominique

    2010-05-01

    After the onset of Gondwana break-up in the Early Mesozoic, the emerged part of the African plate underwent long Greenhouse effect climatic periods and epeirogeny. The last Greenhouse effect period in the Early Cenozoic and the alternation of wet and dry climatic periods since the Eocene enhanced episodes of rock chemical weathering and laterite production, forming bauxites and ferricretes, interrupted by drier periods of dominantly mechanical denudation, shaping glacis [1]. In Sub-Saharan West Africa, this evolution resulted in pulsate and essentially climatically-forced denudation that has shaped an ubiquitous sequence of five stepped lateritic paleosurfaces that synchronously developed over Cenozoic times. The modes, timing and spatial variability of continental denudation of the region are investigated by combining geomorphologic and geochronological data sets. The geomorphologic data set comprises the altitudinal distribution of the lateritic paleosurfaces relicts and their differential elevation from 42 locations in Sub-Saharan West Africa where the sequence (or part of it) has been documented. The geochronological data set consists in the age ranges of each paleosurface tackled by radiometric 39Ar-40Ar dating of the neoformed oxy-hydroxides (i.e., cryptomelane, K1-2Mn8O16, nH2O, [4]) carried by their laterites at the Tambao reference site, Burkina Faso [1, 3]. Five groups of 39Ar-40Ar ages, ~ 59 - 45 Ma, ~ 29 - 24 Ma, ~ 18 - 11.5 Ma, ~ 7.2 - 5.8 Ma, and ~ 3.4 - 2.9 Ma, characterize periods of chemical weathering whereas the time laps between these groups of ages correspond to episodes of mechanical denudation that reflect physical shaping of the paleosurfaces. For the last 45 Ma, the denudation rate estimates (3 to 8 m Ma-1) are comparable with those derived on shorter time scale (103 to 106 y.) in the same region by the cosmogenic radionuclide method [2]. Combined with the geomorphologic data set, these age ranges allow the visualization of the regional

  11. Kinematic structures, diabatic profiles, and precipitation systems in West Africa during summer 2006

    NASA Astrophysics Data System (ADS)

    Davis, Adam James

    This work uses a gridded analysis of radiosonde measurements obtained during AMMA and places those observations in the context of African Monsoon Multidisciplinary Analysis (AMMA) radar data and satellite rainfall estimates to examine the patterns of kinematic and diabatic quantities in West Africa relative to the summer monsoon phase, easterly wave disturbances, precipitation systems, and the diurnal cycle. Many unique aspects of West African weather compared to conditions elsewhere in the tropics are revealed by this study. The meridional transitions related to the West African monsoon comprise the predominant control on the location and intensity of precipitation at seasonal time scales, with variations in convective activity related to the Madden-Julian Oscillation contributing at 25 to 60 day periods. On shorter time scales of two to six days, easterly wave disturbances look to be the principal factor governing the timing of rainfall events, though especially persistent cold pools and residual cloudiness generated by thunderstorm systems also act as constraints on convective evolution on the days following a precipitation episode. One of the most distinctive traits of the study region in West Africa compared to other tropical areas is the particular prevalence of convective downdrafts, chiefly those associated with mesoscale zones of stratiform precipitation in thunderstorm complexes. These features, along with the gravity waves forced by their characteristic heating pattern, have an especially large influence on the time-mean atmospheric structure relative to the majority of the tropics. A comparison of the diabatic profiles from the AMMA dataset with those from other field projects indicates that the signals of both convective downdrafts and diurnal variations of the planetary boundary layer are much stronger in West Africa than in the previously studied regions. Beyond the mentioned differences, though, the AMMA profiles show resemblance to those from both

  12. Evaluating the performance of remotely sensed and reanalysed precipitation data over West Africa using HBV light

    NASA Astrophysics Data System (ADS)

    Poméon, Thomas; Jackisch, Dominik; Diekkrüger, Bernd

    2017-04-01

    Water is a crucial resource in West Africa, where large parts of the population rely on rainfed agriculture. Therefore, accurate knowledge of the water resources is of the utmost importance. Due to the declining number of rain gauging stations, the use of satellite and reanalysis precipitation datasets in hydrological modelling is steadily rising. However, accurate information on the benefits and deficits of these datasets is often lacking, especially in the West African subcontinent. For validation purposes, these products are commonly compared to freely available rain gauge data, which has in some cases already been used to bias correct the products in the first place. We therefore explored the possibility of a hydrological evaluation, where a model is calibrated for each dataset using streamflow as the observed variable. In this study, ten freely available satellite and reanalysis datasets (CFSR, CHIRPS, CMORPHv1.0 CRT, CMORPHv1.0 RAW, PERSIANN CDR, RFE 2.0, TAMSAT, TMPA 3B42v7, TMPA 3B42 RTv7 and GPCC FDDv1) were thus evaluated for six differently sized and located basins in West Africa. Results show that while performances differ, most datasets manage to somewhat accurately predict the observed streamflow in a given basin. Best results were achieved by datasets which use a multitude of input data, namely infrared and microwave satellite data, as well as observations from rain gauges (usually GPCC) for bias correction. If considering only the Nash Sutcliffe Efficiency averaged for all six basins during the calibration phase, best results were achieved by CMORPH CRT and PERSIANN CDR (both 0.66), followed by TAMSAT, CHIRPS and TMPA 3B42 (all three 0.64). Average results were achieved by RFE 2.0 (0.63), GPCC (0.61) and TMPA 3B42 RT (0.54). CMORPH RAW and CFSR performed worst (0.36 and -0.34 on average).

  13. Including Tropical Croplands in a Terrestrial Biosphere Model: Application to West Africa

    NASA Astrophysics Data System (ADS)

    Berg, A.; Sultan, B.; de Noblet, N.

    2008-12-01

    Studying the large-scale relationships between climate and agriculture raises two different issues: the impact of climate on crops, and the potential feedbacks to climate from croplands. A relevant framework to consistently address this twofold issue is to extend existing Dynamic Global Vegetation Models, which can be coupled to climate models, in order to explicitly account for croplands. Here we present the first results of such a strategy applied to tropical croplands over West Africa. We introduce directly into the terrestrial biosphere model ORCHIDEE (IPSL) adequate processes and parametrizations taken from the crop model SARRAH (CIRAD), which is calibrated for millet over this region. The resulting model, ORCH-mil, realistically simulates the growth and yield of millet when tested on an experimental station in Senegal. The model is then applied over West Africa using a 36-year climate reanalysis dataset. First the model is tested in terms of yield simulation, against national millet yields from the FAO database. The ability of the model to reproduce the spatial and temporal variability of millet yields is assessed. Then, the effects on land surface fluxes of explicitly accounting for croplands are examined, by comparison between ORCH-mil and ORCHIDEE. These first simulations show consistent results, but underline the need for some further development and validation of the model if it is to simulate yields accurately. In terms of land surface fluxes, significant differences between ORCH-mil and ORCHIDEE appear, mainly via changes in evaporation and albedo. The potential impact on the west African monsoon system of such differences needs to be investigated by coupling ORCH-mil to a climate model: first results from such an experiment will be presented.

  14. Evaluation of the COSMO-CLM high-resolution climate simulations over West Africa

    NASA Astrophysics Data System (ADS)

    Dieng, Diarra; Smiatek, Gerhard; Bliefernicht, Jan; Heinzeller, Dominikus; Sarr, A.; Gaye, A. T.; Kunstmann, Harald

    2017-02-01

    The evaluation of a high-resolution simulation at 0.11° (12 km) with the COnsortium for Small-scale MOdelling in CLimate Mode (CCLM) regional climate model, applied over West Africa, is presented. This simulation is nested in a CCLM run at resolution of 0.44°, driven with boundary forcing data from the ERA-Interim reanalysis, and covers the period from 1981 to 2010. The simulated temperature and precipitation are evaluated using three selected climate indices for temperature and eight indices for precipitation in five different regions against a new, daily precipitation climatology covering West Africa and against other state of the art climatologies. The obtained results indicate that CCLM is able to reproduce the observed major climate characteristics including the West African Monsoon within the range of comparable regional climate modeling evaluations studies, but substantial uncertainties remain, especially in the Sahel zone. The seasonal mean temperature bias for the rainy season from June to September ranges from -0.8°C to -1.1°C. The CCLM simulations also underestimate the observed precipitation with biases in precipitation reaching -10% in the high-resolution and -20% in the low-resolution model runs. CCLM extends the monsoon precipitation belt too far north, which results in an overestimation of precipitation in the Sahel zone of up to 60%. In the coastal zone, the precipitation is underestimated by up to -90%. These biases in precipitation amounts are associated with errors in the precipitation seasonality. The added value of the higher resolution of the nested run is reflected in a smaller bias in extreme precipitation statistics with respect to the reference data.

  15. Satellite-based Assessment of Fire Impacts on Ecosystem Changes in West Africa

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles

    2008-01-01

    Fires bum many vegetated regions of the world to a variety of degrees and frequency depending on season. Extensive biomass burning occurs in most parts of sub-Saharan Africa, posing great threat to ecosystem stability among other real and potential adverse impacts. In Africa, such landscape-scale fires are used for various agricultural purposes, including land clearing and hunting, although there may be a limited number of cases of fires ignited by accident or due to arson. Satellite remote sensing provides the most practical means of mapping fires, because of their sudden and aggressive nature coupled with the tremendous heat they generate. Recent advancements in satellite technology has enabled, not only the identification of fire locations, but also the measurement of fire radiative energy (FRE) release rate or power (FRP), which has been found to have a direct linear relationship with the rate of biomass combustion. A recent study based on FRP measurements from the Moderate-resolution imaging Spectro-radiometer (MODIS) sensor aboard the Terra and Aqua satellites revealed that, among all the regions of the world where fires occur, African regions rank the highest in the intensity of biomass burning per unit area of land during the peak of the burning season. In this study, we will analyze the burning patterns in West Africa during the last several years and examine the extent of their impacts on the ecosystem dynamics, using a variety of satellite data. The study introduces a unique methodology that can be used to build up the knowledge base from which decision makers can obtain scientific information in fomulating policies for regulating biomass burning in the region.

  16. Vegetation dynamics and climate variability-associated biophysical process in West Africa

    NASA Astrophysics Data System (ADS)

    Song, G.; Xue, Y.; Cox, P. M.

    2012-12-01

    West Africa is a bioclimatic zone of predominantly annual grasses with shrubs and trees with a steep gradient in climate, soils, vegetation, fauna, land use and human utilization. West Africa ecosystem region suffered from the most severe and longest drought in the world during the Twentieth Century since the later 1960s. This study systematically investigates how climate variability and anomalies in West Africa affect the regional terrestrial ecosystem, including plant functional types' (PFT) spatial distribution and temporal variations and vegetation characteristics, through biophysical and photosynthesis processes at different scales. We use the offline Simplified Simple Biosphere Version 4/ Top-down Representation of Interactive Foliage and Flora Including Dynamics Model (SSiB4/TRIFFID), which is a fully coupled biophysical-dynamic vegetation (DVM) model to adequately incorporate the complex non-linear coupling dynamics between ecosystem and climate variability. The biophysical parameters in SSiB4 are adjusted with TRIFFID-produced vegetation parameter values, which ensure adequate biophysical process coupling. A 59-year simulation from 1948 was conducted using the meteorological forcing, which consists of substantial seasonal, interannual, and interdecal variability and long term dry trend. The results show that the simulated PFT's and leaf area index (LAI) correspond well to climate variability and are consistent with satellite derived vegetation conditions. The simulated inter-decadal variability in vegetation conditions is consistent with the Sahel drought in the 1970s and the 1980s and partial recovery in the 1990s and the 2000s (fig1). To further understand the biophysical mechanism of interactions of water, carbon, radiation, and vegetation dynamics, analyses are conducted to find relationships between vegetation variability and environmental conditions. It is found that the vegetation characteristics simulated by SSiB4/TRIFFID responds primarily to five

  17. Incidence of Severe Neutropenia in HIV-Infected People Starting Antiretroviral Therapy in West Africa

    PubMed Central

    Leroi, Charline; Balestre, Eric; Messou, Eugene; Minga, Albert; Sawadogo, Adrien; Drabo, Joseph; Maiga, Moussa; Zannou, Marcel; Seydi, Moussa; Dabis, Francois; Jaquet, Antoine

    2017-01-01

    Background In sub-Saharan Africa, antiretroviral therapy (ART) including drugs with potential toxicity such as Zidovudine (ZDV) are routinely prescribed. This study aimed at estimating the incidence of severe neutropenia and associated factors after ART initiation in five West African countries. Methods A retrospective cohort analysis was conducted within the international epidemiologic database to evaluate AIDS (IeDEA) collaboration in West Africa. All HIV-infected adults, initiating ART between 2002 and 2014, with a baseline and at least one follow-up absolute neutrophil count (ANC) measurement were eligible. Incidence of severe neutropenia (ANC <750 cells/mm3) was estimated with 95% confidence interval (CI) according to age, gender, HIV clinic, hemoglobin, CD4 count, clinical stage, and ART duration. A Cox proportional hazard model was used to identify factors associated with severe neutropenia, expressed with their adjusted hazard ratios (aHR). Results Between 2002 and 2014, 9,426 HIV-infected adults were enrolled. The crude incidence rate of a first severe neutropenia was 9.1 per 100 person-years (95% CI: 8.6–9.8). Factors associated with severe neutropenia were exposure to ZDV <6 months (aHR = 2.2; 95% CI: 1.8–2.6), ≥6–12 months (aHR = 2.1; 95% CI: 1.6–2.8) and ≥12 months (aHR = 1.6; 95% CI: 1.2–2.2) [Ref. no ZDV exposure], CD4 count <350 cells/mm3 (aHR = 1.3; 95% CI: 1.1–1.5) and advanced clinical stage at ART initiation (aHR = 1.2; 95% CI: 1.0–1.4). Conclusion The incidence of severe neutropenia after ART initiation in West Africa is high and associated with ZDV exposure and advanced HIV disease. In this context, efforts are needed to scale-up access to less toxic first-line ART drugs and to promote early ART initiation. PMID:28122041

  18. The prevalence, awareness, and control of hypertension among workers in West Africa: a systematic review

    PubMed Central

    Bosu, William K.

    2015-01-01

    Background Interventions in workplace settings are considered to be cost-effective in preventing cardiovascular diseases. A systematic review was conducted to assess the prevalence of hypertension and the level of awareness and control among workers in West Africa. Design A systematic search for studies on formal and informal sector workers aged ≥15 years in West Africa published between 1980 and September 2014 was undertaken using the Ovid Medline, Embase, PubMed, and Google Scholar databases. Clinical and obstetric studies and studies that did not report prevalence were excluded. Data on study settings, characteristics of workers, blood pressure (BP) levels, prevalence of hypertension, and associated demographic factors were extracted. Results A total of 45 studies from six countries were identified involving 30,727 formal and informal sector workers. In 40 studies with a common definition of hypertension, the prevalence ranged from 12.0% among automobile garage workers to 68.9% among traditional chiefs. In 15 of these studies, the prevalence exceeded 30%. Typically sedentary workers such as traders, bank workers, civil servants, and chiefs were at high risk. Among health care workers, the prevalence ranged from 17.5 to 37.5%. The prevalence increased with age and was higher among males and workers with higher socio-economic status. Complications of hypertension, co-morbidities, and clustering of risk factors were common. The crude prevalence of hypertension increased progressively from 12.9% in studies published in the 1980s to 34.4% in those published in 2010–2014. The proportion of hypertensives who were previously aware of their diagnosis, were on treatment or had their BP controlled was 19.6–84.0%, 0–79.2%, and 0–12.7%, respectively. Hypertensive subjects, including health workers, rarely checked their BP except when they were ill. Conclusions There is a high prevalence of hypertension among West Africa's workforce, of which a significant

  19. Mapping transmission risk of Lassa fever in West Africa: the importance of quality control, sampling bias, and error weighting.

    PubMed

    Peterson, A Townsend; Moses, Lina M; Bausch, Daniel G

    2014-01-01

    Lassa fever is a disease that has been reported from sites across West Africa; it is caused by an arenavirus that is hosted by the rodent M. natalensis. Although it is confined to West Africa, and has been documented in detail in some well-studied areas, the details of the distribution of risk of Lassa virus infection remain poorly known at the level of the broader region. In this paper, we explored the effects of certainty of diagnosis, oversampling in well-studied region, and error balance on results of mapping exercises. Each of the three factors assessed in this study had clear and consistent influences on model results, overestimating risk in southern, humid zones in West Africa, and underestimating risk in drier and more northern areas. The final, adjusted risk map indicates broad risk areas across much of West Africa. Although risk maps are increasingly easy to develop from disease occurrence data and raster data sets summarizing aspects of environments and landscapes, this process is highly sensitive to issues of data quality, sampling design, and design of analysis, with macrogeographic implications of each of these issues and the potential for misrepresenting real patterns of risk.

  20. Walking the Path: A Reflection on How I Got Started at Tuskegee International School, Ghana, West Africa

    ERIC Educational Resources Information Center

    Greenberg, Bev

    2011-01-01

    The author has given meaning to global citizenship over the past four years through the work and connections she has made with students at her school in Chicago, Francis W. Parker, and a school in the village of Madina, Ghana, West Africa, Tuskegee International. She has motivated other teachers to make connections as they traveled with her to…

  1. The Affect of Drug Trafficking in West Africa on the National Security Interests of the United States of America

    DTIC Science & Technology

    2015-06-12

    Latin America and Asia to end users in North America, Europe, the Middle East, and Asia. The type of illegal substances has expanded from cocaine and...heroin to amphetamine- type stimulants. West Africa is particularly susceptible to influence by transnational criminal organizations (TCOs) due to

  2. Monitoring HIV Risk and Evaluating Interventions among Young People in Urban West Africa: Development and Validation of an Instrument

    ERIC Educational Resources Information Center

    Boileau, Catherine; Rashed, Selim; Sylla, Mohamed; Zunzunegui, Maria Victoria

    2008-01-01

    We developed an instrument for HIV/AIDS behavioral surveillance applicable to youth living in urban West Africa. The instrument includes a comprehensive set of constructs borrowed from the sociocognitive theory of planned behavior as well as measures of parental and peer communication An exploratory (n = 189) and validation sample (n = 342) of…

  3. The mineralogy of global magnetic anomalies. [rock magnetic signatures and MAGSAT geological, and gravity correlations in West Africa

    NASA Technical Reports Server (NTRS)

    Haggerty, S. E. (Principal Investigator)

    1982-01-01

    Problems with the Curie balance, which severely hindered the acquisition of data, were rectified. Chemical analytical activities are proceeding satisfactorily. The magnetization characteristics of metamorphic suites were analyzed and susceptibility data for a wide range of metamorphic and igneous rocks. These rock magnetic signatures are discussed as well as the relationships between geology, gravity and MAGSAT anomalies of West Africa.

  4. The spatial genetic differentiation of the legume pod borer, Maruca vitrata F. (Lepidoptera: Pyralidae) populations in West Africa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The legume pod borer, Maruca vitrata, is an endemic insect pest that causes significant yield loss to the cowpea crop in West Africa, and contributes to food shortages and malnutrition in native human populations. The genetic structure of Maruca vitrata was investigated among five sites from Burkin...

  5. New evidence for hybrid zones of forest and savanna elephants in Central and West Africa.

    PubMed

    Mondol, Samrat; Moltke, Ida; Hart, John; Keigwin, Michael; Brown, Lisa; Stephens, Matthew; Wasser, Samuel K

    2015-12-01

    The African elephant consists of forest and savanna subspecies. Both subspecies are highly endangered due to severe poaching and habitat loss, and knowledge of their population structure is vital to their conservation. Previous studies have demonstrated marked genetic and morphological differences between forest and savanna elephants, and despite extensive sampling, genetic evidence of hybridization between them has been restricted largely to a few hybrids in the Garamba region of northeastern Democratic Republic of Congo (DRC). Here, we present new genetic data on hybridization from previously unsampled areas of Africa. Novel statistical methods applied to these data identify 46 hybrid samples--many more than have been previously identified--only two of which are from the Garamba region. The remaining 44 are from three other geographically distinct locations: a major hybrid zone along the border of the DRC and Uganda, a second potential hybrid zone in Central African Republic and a smaller fraction of hybrids in the Pendjari-Arli complex of West Africa. Most of the hybrids show evidence of interbreeding over more than one generation, demonstrating that hybrids are fertile. Mitochondrial and Y chromosome data demonstrate that the hybridization is bidirectional, involving males and females from both subspecies. We hypothesize that the hybrid zones may have been facilitated by poaching and habitat modification. The localized geography and rarity of hybrid zones, their possible facilitation from human pressures, and the high divergence and genetic distinctness of forest and savanna elephants throughout their ranges, are consistent with calls for separate species classification.

  6. Public health professionals’ perceptions of mental health services in Equatorial Guinea, Central-West Africa

    PubMed Central

    Reuter, Peter Robert; McGinnis, Shannon Marcail; Reuter, Kim Eleanor

    2016-01-01

    Introduction Mental health disorders constitute 13% of global disease burden, the impacts of which are disproportionality felt in sub-Saharan Africa. Equatorial Guinea, located in Central-West Africa, has the highest per-capita investment in healthcare on the African continent, but only two studies have discussed mental health issues in the country and none of have examined the perspective of professionals working in the field. The purpose of this study was to gain a preliminary understanding of Equatoguinean health care professionals' perspectives on the mental health care system. Methods Nine adult participants (directors or program managers) were interviewed in July 2013 in Malabo, Equatorial Guinea from government agencies, aid organizations, hospitals, and pharmacies. Interviews were designed to collect broad information about the mental healthcare system in Equatorial Guinea including the professionals' perspectives and access to resources. This research was reviewed and approved by an ethical oversight committee. Results All individuals interviewed indicated that the mental health system does not currently meet the needs of the community. Professionals cited infrastructural capacity, stigmatization, and a lack of other resources (training programs, knowledgeable staff, medications, data) as key factors that limit the effectiveness of mental healthcare. Conclusion This study provides a preliminary understanding of the existing mental health care needs in the country, highlighting opportunities for enhanced healthcare services. PMID:28293352

  7. Determinants of Mean Blood Pressure and Hypertension among Workers in West Africa

    PubMed Central

    Bosu, William K.

    2016-01-01

    Background. This review was undertaken to estimate the mean blood pressure and evaluate its determinants as well as the determinants of hypertension among workers in West Africa. Methods. In a follow-up to an earlier study, a systematic search for articles published between 1980 and August 2015 was undertaken using major databases. Results. A total of 55 articles involving 34,919 different cadres of workers from six countries were retrieved. The mean systolic blood pressure (BP) ranged from 116.6 ± 1.3 mmHg to 151.7 ± 13.6 mmHg while the mean diastolic BP ranged from 69.6 ± 11.0 mmHg to 97.1 ± 9.1 mmHg. Population-wide prehypertension was common. The major determinants of mean BP and hypertension were similar and included male sex, older age group, higher socioeconomic status, obesity, alcohol consumption, plasma glucose, and sodium excretion. Ethnicity and educational level were inconsistently associated with hypertension. Workers at higher risk of cardiovascular event did not perceive themselves as such. Conclusion. The prevailing mean prehypertensive BP, low perception of risk, and clustering of risk factors call for interventions such as healthy diets, improved physical activity, and a favourable work environment. Successful models for improving the cardiovascular health of sedentary informal sector workers in Africa are urgently needed. PMID:26949543

  8. Insecticide dissipation from soil and plant surfaces in tropical horticulture of southern Benin, West Africa.

    PubMed

    Rosendahl, Ingrid; Laabs, Volker; Atcha-Ahowé, Cyrien; James, Braima; Amelung, Wulf

    2009-06-01

    In Sub-Saharan Africa, horticulture provides livelihood opportunities for millions of people, especially in urban and peri-urban areas. Although the vegetable agroecosystems are often characterized by intensive pesticide use, risks resulting therefrom are largely unknown under tropical horticultural conditions. The objective of this study therefore was to study the fate of pesticides in two representative horticultural soils (Acrisol and Arenosol) and plants (Solanum macrocarpon L.) after field application and thus to gain first insight on environmental persistence and dispersion of typical insecticides used in vegetable horticulture in Benin, West Africa. On plant surfaces, dissipation was rapid with half lives ranging from 2 to 87 h (alpha-endosulfan < beta-endosulfan < deltamethrin). Soil dissipation was considerably slower than dissipation from plant surfaces with half-lives ranging from 3 (diazinon) to 74 d (total endosulfan), but persistence of pesticides in soil was still reduced compared to temperate climates. Nevertheless, for deltamethrin and endosulfan, a tendency for mid-term accumulation in soil upon repeated applications was observed. The soil and plant surface concentrations of the metabolite endosulfan sulfate increased during the entire trial period, indicating that this compound is a potential long-term pollutant even in tropical environments.

  9. Climate forecasts in disaster management: Red Cross flood operations in West Africa, 2008.

    PubMed

    Braman, Lisette Martine; van Aalst, Maarten Krispijn; Mason, Simon J; Suarez, Pablo; Ait-Chellouche, Youcef; Tall, Arame

    2013-01-01

    In 2008, the International Federation of Red Cross and Red Crescent Societies (IFRC) used a seasonal forecast for West Africa for the first time to implement an Early Warning, Early Action strategy for enhanced flood preparedness and response. Interviews with disaster managers suggest that this approach improved their capacity and response. Relief supplies reached flood victims within days, as opposed to weeks in previous years, thereby preventing further loss of life, illness, and setbacks to livelihoods, as well as augmenting the efficiency of resource use. This case demonstrates the potential benefits to be realised from the use of medium-to-long-range forecasts in disaster management, especially in the context of potential increases in extreme weather and climate-related events due to climate variability and change. However, harnessing the full potential of these forecasts will require continued effort and collaboration among disaster managers, climate service providers, and major humanitarian donors.

  10. Perspectives on West Africa Ebola Virus Disease Outbreak, 2013-2016

    DOE PAGES

    Spengler, Jessica R.; Ervin, Elizabeth D.; Towner, Jonathan S.; ...

    2016-06-01

    The variety of factors that contributed to the initial undetected spread of Ebola virus disease in West Africa during 2013-2016 and the difficulty controlling the outbreak once the etiology was identified highlight priorities for disease prevention, detection, and response. These factors include occurrence in a region recovering from civil instability and lacking experience with Ebola response; inadequate surveillance, recognition of suspected cases, and Ebola diagnosis; mobile populations and extensive urban transmission; and the community's insufficient general understanding about the disease. The magnitude of the outbreak was not attributable to a substantial change of the virus. Finally, continued efforts during themore » outbreak and in preparation for future outbreak response should involve identifying the reservoir, improving in-country detection and response capacity, conducting survivor studies and supporting survivors, engaging in culturally appropriate public education and risk communication, building productive interagency relationships, and continuing support for basic research.« less

  11. Not just malaria: Mary Slessor (1848-1915) and other Victorian missionaries in West Africa.

    PubMed

    Hardage, Jeanette

    2006-11-01

    Fear of 'fever' was uppermost in the minds of many travellers to West Africa in Victorian times. 'Not just malaria...' chronicles attitudes, treatments and discoveries regarding malaria from the time of David Livingstone through the early 20th century. Missionaries often found themselves in the position of serving as untrained doctors and nurses among the people they went to evangelize. In addition, they suffered from the same maladies as the people did, and many died from malaria or other afflictions. Mary Slessor arrived in Calabar, in what is now southeastern Nigeria, to serve with the Scottish Presbyterian Mission in 1876. With only a few furloughs, she remained there until her death in 1915. The article relates instances of the illnesses and injuries she treated as well as those she suffered herself. She is remembered in Nigeria with statues and, along with David Livingstone, is one of Scotland's best-known missionary figures.

  12. Perspectives on West Africa Ebola Virus Disease Outbreak, 2013–2016

    PubMed Central

    Spengler, Jessica R.; Ervin, Elizabeth D.; Towner, Jonathan S.; Rollin, Pierre E.

    2016-01-01

    The variety of factors that contributed to the initial undetected spread of Ebola virus disease in West Africa during 2013–2016 and the difficulty controlling the outbreak once the etiology was identified highlight priorities for disease prevention, detection, and response. These factors include occurrence in a region recovering from civil instability and lacking experience with Ebola response; inadequate surveillance, recognition of suspected cases, and Ebola diagnosis; mobile populations and extensive urban transmission; and the community’s insufficient general understanding about the disease. The magnitude of the outbreak was not attributable to a substantial change of the virus. Continued efforts during the outbreak and in preparation for future outbreak response should involve identifying the reservoir, improving in-country detection and response capacity, conducting survivor studies and supporting survivors, engaging in culturally appropriate public education and risk communication, building productive interagency relationships, and continuing support for basic research. PMID:27070842

  13. Assessment of vaccination coverage, vaccination scar rates, and smallpox scarring in five areas of West Africa*

    PubMed Central

    Henderson, Ralph H.; Davis, Hillard; Eddins, Donald L.; Foege, William H.

    1973-01-01

    In 1966, nineteen countries of West and Central Africa began a regional smallpox eradication and measles control programme in cooperation with the World Health Organization. This paper summarizes sample survey data collected to assess the results of the programme in Northern Nigeria (Sokoto and Katsina Provinces), Western Nigeria, Niger, Dahomey, and Togo. These data indicate that the programme, which used mass vaccination campaigns based on a collecting-point strategy, was generally successful in reaching a high proportion of the population. Analysis of vaccination coverage and vaccination scar rates by age underlined the importance to the programme of newborn children who accumulate rapidly following the mass campaign. Of all persons without vaccination scars at the time of the surveys, 34.4% were under 5 years of age; in the absence of a maintenance programme, this figure would rise to 40% after 1 year. PMID:4541684

  14. Remote sensing experiment in West Africa. [drought effects on desert agriculture and vegetation in Niger

    NASA Technical Reports Server (NTRS)

    Macleod, N. H.

    1974-01-01

    There are substantial needs of the Sahelien Zone to detail the state of regional agricultural resources in the face of a sixth year of serious drought conditions. While most of the work has been done in the Republic of Niger, the principles which have emerged from the analysis seem to be applicable to much of the Sahel. The discussion relates to quite specific rehabilitation and development initiations under consideration in Niger which are based in part upon direct analysis of ERTS imagery of the country, in part on field surveys and on discussions with Nigerian officials and technicians. Again, because the entire Sahelien Zone (including Niger) has large zones of similar ecologic characteristics, modificiations of the approaches suggested for Niger are applicable to the solution of rehabilitation of the desert, the savannah and the woodlands of West Africa in general.

  15. Rift Valley fever in West Africa: the role of space in endemicity.

    PubMed

    Favier, Charly; Chalvet-Monfray, Karine; Sabatier, Philippe; Lancelot, Renaud; Fontenille, Didier; Dubois, Marc A

    2006-12-01

    Rift Valley fever is an endemic vector-borne disease in West Africa, which mainly affects domestic ruminants and occasionally humans. The aetiological mechanisms of its endemicity remain under debate. We used a simple spatially explicit model to assess the possibility of endemicity without wild animals providing a permanent virus reservoir. Our model takes into account the vertical transmission in some mosquito species, the rainfall-driven emergence of their eggs and local and distant contacts because of herd migration. Endemicity without such a permanent virus reservoir would be impossible in a single site except when there is a strictly periodic rainfall pattern; but it would be possible when there are herd movements and sufficient inter-site variability in rainfall, which drives mosquito emergence.

  16. Satellite data transmission and hydrological forecasting in the fight against Onchocerciasis in west Africa

    NASA Astrophysics Data System (ADS)

    Servat, Eric; Lapetite, Jean-Marc; Bader, Jean-Claude; Boyer, Jean-Francois

    1990-09-01

    Onchocerciasis, or river blindness, is an endemic disease which causes great hardship in west Africa. Within the World Health Organization's Onchocerciasis Control Program (WHO/OCP), reliable data on the discharge of the watercourses have been obtained by using remote satellite transmission. These data are necessary to calculate how much insecticide should be introduced into the rivers. A description of the equipment and its use is followed by an initial report covering the functioning of the equipment, its efficiency and the economies attained. The improvement in the resulting treatment and the reduction in the running costs of the programme are discussed. Software for forecasting the discharge over different time intervals was developed by ORSTOM at the request of the OCP. The different functions of this software (PERLES) are described. In conclusion, the advantages of remote transmission techniques for operational hydrology in general are discussed (flood warning systems, hydrological networks, etc.).

  17. Perspectives on West Africa Ebola Virus Disease Outbreak, 2013-2016

    SciTech Connect

    Spengler, Jessica R.; Ervin, Elizabeth D.; Towner, Jonathan S.; Rollin, Pierre E.; Nichol, Stuart T.

    2016-06-01

    The variety of factors that contributed to the initial undetected spread of Ebola virus disease in West Africa during 2013-2016 and the difficulty controlling the outbreak once the etiology was identified highlight priorities for disease prevention, detection, and response. These factors include occurrence in a region recovering from civil instability and lacking experience with Ebola response; inadequate surveillance, recognition of suspected cases, and Ebola diagnosis; mobile populations and extensive urban transmission; and the community's insufficient general understanding about the disease. The magnitude of the outbreak was not attributable to a substantial change of the virus. Finally, continued efforts during the outbreak and in preparation for future outbreak response should involve identifying the reservoir, improving in-country detection and response capacity, conducting survivor studies and supporting survivors, engaging in culturally appropriate public education and risk communication, building productive interagency relationships, and continuing support for basic research.

  18. Hantaviruses in Africa.

    PubMed

    Witkowski, Peter T; Klempa, Boris; Ithete, Ndapewa L; Auste, Brita; Mfune, John K E; Hoveka, Julia; Matthee, Sonja; Preiser, Wolfgang; Kruger, Detlev H

    2014-07-17

    This paper summarizes the progress in the search for hantaviruses and hantavirus infections in Africa. After having collected molecular evidence of an indigenous African hantavirus in 2006, an intensive investigation for new hantaviruses has been started in small mammals. Various novel hantaviruses have been molecularly identified not only in rodents but also in shrews and bats. In addition, the first African hantavirus, Sangassou virus, has been isolated and functionally characterized in cell culture. Less is known about the ability of these hantaviruses to infect humans and to cause diseases. To date, no hantavirus genetic material could be amplified from patients' specimens collected in Africa. Serological studies in West Africa, based on a battery of screening and confirmatory assays, led to the detection of hantavirus antibodies in the human population and in patients with putative hantavirus disease. In addition to this overview, we present original data from seroepidemiological and field studies conducted in the Southern part of Africa. A human seroprevalence rate of 1.0% (n=1442) was detected in the South African Cape Region whereas no molecular evidence for the presence of hantavirus was found in 2500 small animals trapped in South Africa and Namibia.

  19. Relief inversion in the geomorphological evolution of sub-Saharan West Africa

    NASA Astrophysics Data System (ADS)

    Butt, C. R. M.; Bristow, A. P. J.

    2013-03-01

    The geomorphology of much of sub-Saharan West Africa is dominated by the presence of plateaux and plains with ferruginous and, locally, aluminous (bauxitic) duricrusts. The plateaux occur at different elevations and have been correlated as two or more palaeosurfaces across much of the region. The duricrusts have generally been considered to be residual, formed by conformable erosion and chemical wasting of immediately underlying bedrock. This concept has been central to interpretations as diverse as the formation and evolution of the landscape and the development of geochemical exploration models. Recent regolith landform mapping, field observations and experience from mineral exploration in southern Mali and Burkina Faso, however, demonstrate that the duricrusts are mainly ferricretes, i.e., Fe oxide-cemented sediments. These observations require a re-interpretation of the geomorphological evolution of the region during the Cenozoic. The landscape has evolved by several cycles of weathering and erosion-deposition, triggered by climatic, tectonic or other environmental changes. It is proposed that an initial bauxitic/lateritic regolith was partly eroded following uplift and/or a change to a more arid climate, and that the detritus, rather than being removed, was deposited on slopes and valleys. During a subsequent humid period of lateritic weathering, Fe oxide cementation of this detritus formed ferricrete. Dehydration and hardening of the ferricrete after further uplift or aridity increased its resistance to erosion, resulting in relief inversion, with the detritus, in turn, being deposited downslope. This too has been weathered and cemented, to form a younger ferricrete. The occurrence of ferricrete landforms in adjacent countries, noted by field observation and inferred from satellite imagery, demonstrates that relief inversion is a very widespread and important phenomenon in southern Mali, Burkina Faso and adjacent countries in semi-arid West Africa.

  20. Secondary organic aerosol from biogenic VOCs over West Africa during AMMA

    NASA Astrophysics Data System (ADS)

    Capes, G.; Murphy, J. G.; Reeves, C. E.; McQuaid, J. B.; Hamilton, J. F.; Hopkins, J. R.; Crosier, J.; Williams, P. I.; Coe, H.

    2009-06-01

    This paper presents measurements of organic aerosols above subtropical West Africa during the wet season using data from the UK Facility for Airborne Atmospheric Measurements (FAAM) aircraft. Measurements of biogenic volatile organic compounds (BVOC) at low altitudes over these subtropical forests were made during the African Monsoon Multidisciplinary Analysis (AMMA) field experiment during July and August 2006 mainly above Benin, Nigeria and Niger. Data from an Aerodyne Quadrupole Aerosol Mass Spectrometer show a median organic aerosol loading of 1.07 μg m-3 over tropical West Africa, which represents the first regionally averaged assessment of organic aerosol mass (OM) in this region during the wet season. This is broadly in agreement with global model predictions based on partitioning schemes, although there are large uncertainties associated with such estimates. In contrast our own calculations based on aerosol yields from isoprene and monoterpenes during chamber studies under represent the OM measured in this region on a comparable scale to the under representations of OM by predictive models in the mid latitudes. As global models rely on similar yield calculations in their global estimates, as our calculations this points to further systematic differences between global model estimates and measurements of SOA, most likely caused by use of incorrect BVOC emission rates. The under predictions of OM by our calculations and those in the mid latitudes employ yields extrapolated from chamber data obtained at higher mass concentrations - more recent yield data for α-pinene obtained at ambient concentrations in a flow through chamber (Shilling et al., 2008) show considerably better agreement with our data.

  1. Experiences and Psychosocial Impact of West Africa Ebola Deployment on US Health Care Volunteers

    PubMed Central

    Gershon, Robyn; Dernehl, Liza A.; Nwankwo, Ezinne; Zhi, Qi; Qureshi, Kristine

    2016-01-01

    Background: This qualitative study was designed to assess health care volunteers’ experiences and psychosocial impacts associated with deployment to the West Africa Ebola epidemic. Methods: In 2015, using snowball sampling, 16 US health care volunteers who had recently returned from West Africa were recruited for this study. Semi-structured interviews were conducted to collect information associated with each phase of deployment (pre, peri, and post). Results: Participants reported that they were motivated to volunteer because of a sense of responsibility and feelings of empathy and altruism. Immediately prior to deployment, most reported fear of contagion and death, as well as doubts regarding the adequacy of their training. Family members and close friends expressed high levels of concern regarding participants’ decisions to volunteer. During the deployment, participants were fearful of exposure and reported feeling emotionally and physically exhausted. They also reported feeling frustrated by extreme resource limitations, poor management of the mission, lack of clearly defined roles and responsibilities, and inability to provide high quality care. Upon return home, participants felt a sense of isolation, depression, stigmatization, interpersonal difficulties, and extreme stress. Conclusion: Preparedness of volunteers was suboptimal at each stage of deployment. All stakeholders, including volunteers, sponsoring organizations, government agencies, and professional organizations have a shared responsibility in ensuring that volunteers to medical missions are adequately prepared. This is especially critical for high risk deployments. Effective policies and practices need to be developed and implemented in order to protect the health and well-being of health care volunteers to the fullest extent possible. PMID:27803840

  2. How influences on teenage smoking reflect gender and society in Mali, West Africa

    PubMed Central

    Kirk, Anna

    2012-01-01

    Objectives To provide further understanding and discussion on the influences on smoking in young people in Mali. Design A generic qualitative methodological approach was used following Caelli's generic principles. Six focus group discussions were conducted with a total of 31 participants followed by two semi-structured interviews. A reflexive account was kept to record development in the researcher's theoretical position Setting The setting was recreational areas of Bamako, capital city of Mali, West Africa. Participants Participants aged 13–15 years were recruited opportunistically in a recreational area of Bamako. Mainoutcome measures To develop further understanding of the influences of teenage smoking in Mali, West Africa. Results Five main categories that explained influences on youth smoking emerged: knowledge and awareness of smoking; associations with smoking; influential people; key messages in Malian society; and access to tobacco. The results showed that influences were complex and interwoven, notable gender differences were revealed, and the role of elder members of the community proved decisive in participants' smoking experiences. Participants described vague knowledge of the impact on health of smoking and reported trying smoking from an early age. Often contact with smoking was through elders and being sent to buy and sometimes light cigarettes for them. Associations with smoking were influenced by gender with smoking more desirable for boys than girls. Conclusions Any approach to preventing smoking initiation in young people requires an understanding of the social influences and pressures on young people. A tobacco control strategy is required to look at all areas of influence on smoking behaviours. Different needs should also account for the differing characteristics and perceptions of specific population groups. PMID:22299069

  3. Climatic and Human Influence on Tropical Forest Degradation in West Africa

    NASA Astrophysics Data System (ADS)

    Liu, Z., Sr.; Wimberly, M. C.; Dwomoh, F. K.

    2015-12-01

    The Upper Guinean Forests of West Africa encompass one of most fragmented and endangered tropical forest ecosystems on earth. However, relatively little is known about the extent and causes of forest degradation in this heavily human affected region. We used the tasseled cap wetness (TCW) index to detect forest degradation using dry-season imagery from 2001 to 2015. TCW was calculated from MODIS (or Moderate Resolution Imaging Spectroradiometer) Nadir BRDF-Adjusted Reflectance (NBAR) at 500 meter resolution. The TCW index was compared with field data and high-resolution imagery and was found to have a strong relationship with different level of forest degradation, with lower TCW index values indicating higher levels of degradation. Mann-Kendall tests were used to detect the monotonic decreases in TCW index. Results indicated that about 12.9% of tropical forest in West Africa has been degraded during past 15 years, and most of these areas were located in isolated forest patches and on the periphery of intact forest. The boosted regression tree (BRT) method was then used to assess the influence of climate and human influence on forest degradation. BRT analysis indicated that climatic variations, human activities, and their interactions were important contributors to forest degradation. Major drivers of forest degradation included distance to cropland, rainfall trend, and rate of population growth.. Our results show that times series of coarse-resolution MODIS imagery can be used for broad-scale assessment of tropical forest degradation, and human activities need to be taken into account when assessing potential forest responses to climate change in this region.

  4. « Younger-Dryas / African Humid Period »: a notable climatic transition over West Africa

    NASA Astrophysics Data System (ADS)

    Skonieczny, C.; Bory, A. J.; Bout-Roumazeilles, V.; Malaizé, B.; Grousset, F. E.; Abouchami, W.; Galer, S. J.; Francois, R. H.

    2013-05-01

    Every year, several hundreds teragrams of dust are emitted from the Sahara and Sahel regions. These mineral particles sensitively track variations in atmospheric circulation and continental aridity. Sediments of the Northeastern Atlantic Tropical Ocean (NEATO) are fed by this intense dust supply and comprise unique long-term archives of past dust emissions. Past modifications of dust characteristics in these sedimentary archives can provide precious information on changes in environmental conditions in source areas (aridity, weathering), as well as on changes in the characteristics of their atmospheric transport (pathways and strength). Over Africa, gradual increases in local insolation due to changes in the Earth's orbit are accompanied by a migration of the precipitation monsoon-system (associated with the InterTropical Convergence Zone, ITCZ) toward the North. This displacement leads to decrease in West African mineral dust emission. Consequently, Saharan and Sahelian dust deposited in the NEATO sedimentary archives represent an exceptional opportunity to document the environmental and climatic changes that have taken place in West Africa throughout the Quaternary and beyond (Rea, 1994). Here we document changes in the terrigenous supplies to the NETAO throughout the last deglaciation using the marine sediment core MD03-2705 located off Mauritania (18°05N; 21°09W; 3085m water depth) and retrieved from a bathymetric dome, 300 meters above the surrounding seafloor. Considering this particular environmental setting, the terrigenous fraction in this record is assumed to be predominantly of aeolian origin. Multi-proxy analyses of the carbonate-free fraction of the sediment were carried-out, including dust fluxes, grain-size, clay mineralogy and geochemical measurements (major and trace elements as well as Sr & Nd isotopes). We will discuss the most significant changes recorded over the studied period: levels dated from the Younger Dryas and the subsequent African

  5. Reasons for hospitalization in HIV-infected children in West Africa

    PubMed Central

    Dicko, Fatoumata; Desmonde, Sophie; Koumakpai, Sikiratou; Dior-Mbodj, Hélène; Kouéta, Fla; Baeta, Novisi; Koné, Niaboula; Akakpo, Jocelyn; Sy, Haby Signate; Ye, Diarra; Renner, Lorna; Lewden, Charlotte; Leroy, Valériane

    2014-01-01

    Introduction Current knowledge on morbidity and mortality in HIV-infected children comes from data collected in specific research programmes, which may offer a different standard of care compared to routine care. We described hospitalization data within a large observational cohort of HIV-infected children in West Africa (IeDEA West Africa collaboration). Methods We performed a six-month prospective multicentre survey from April to October 2010 in five HIV-specialized paediatric hospital wards in Ouagadougou, Accra, Cotonou, Dakar and Bamako. Baseline and follow-up data during hospitalization were recorded using a standardized clinical form, and extracted from hospitalization files and local databases. Event validation committees reviewed diagnoses within each centre. HIV-related events were defined according to the WHO definitions. Results From April to October 2010, 155 HIV-infected children were hospitalized; median age was 3 years [1–8]. Among them, 90 (58%) were confirmed for HIV infection during their stay; 138 (89%) were already receiving cotrimoxazole prophylaxis and 64 children (40%) had initiated antiretroviral therapy (ART). The median length of stay was 13 days (IQR: 7–23); 25 children (16%) died during hospitalization and four (3%) were transferred out. The leading causes of hospitalization were WHO stage 3 opportunistic infections (37%), non-AIDS-defining events (28%), cachexia and other WHO stage 4 events (25%). Conclusions Overall, most causes of hospitalizations were HIV related but one hospitalization in three was caused by a non-AIDS-defining event, mostly in children on ART. HIV-related fatality is also high despite the scaling-up of access to ART in resource-limited settings. PMID:24763078

  6. Role of the biosphere in the mid-Holocene climate of West Africa

    NASA Astrophysics Data System (ADS)

    Irizarry-Ortiz, Michelle M.; Wang, Guiling; Eltahir, Elfatih A. B.

    2003-01-01

    In previous studies, a zonally symmetric, synchronously coupled biosphere-atmosphere model (ZonalBAM), which includes explicit representation of ecosystem dynamics, has been developed and validated based on current conditions over the region of West Africa. Here, we use ZonalBAM to study the response of the coupled biosphere-atmosphere system to changes in the Earth's orbital forcing during the Middle Holocene (6K yrs BP) and the relative contribution of vegetation feedbacks. Simulations in which vegetation conditions were fixed to the current distribution, show that an orbitally induced increased seasonality in insolation for the Middle Holocene, by itself, results in a 1.1° northward shift in the location of the southern margin of the Sahara as compared to current solar forcings. When vegetation is allowed to be dynamic, a 2.4° northward shift is simulated. However, when dynamic vegetation is initialized to palaeovegetation, a 5.1° northward shift is simulated, bringing results more consistent with palaeoevidence. Based on previous studies on the role of the gradient of moist static energy on the dynamics of large-scale tropical circulations, a mechanism for the enhancement of the summer monsoon circulation has been developed. Our results suggest that multiple equilibria could have coexisted over the region of West Africa during the Middle Holocene. Furthermore, based on previous studies on the current climate over the region, we hypothesize that transitions between the different equilibria could have taken place during the Middle Holocene causing the southern desert margin to migrate between 18.1°N and 21.4°N and shaping climate variability.

  7. Regional assessment of the hydropower potential of rivers in West Africa

    NASA Astrophysics Data System (ADS)

    Kling, Harald; Stanzel, Philipp; Fuchs, Martin

    2016-04-01

    The 15 countries of the Economic Community of West African States (ECOWAS) face a constant shortage of energy supply, which limits sustained economic growth. Currently there are about 50 operational hydropower plants and about 40 more are under construction or refurbishment. The potential for future hydropower development - especially for small-scale plants in rural areas - is assumed to be large, but exact data are missing. This study supports the energy initiatives of the "ECOWAS Centre for Renewable Energy and Energy Efficiency" (ECREEE) by assessing the hydropower potential of all rivers in West Africa. For more than 500,000 river reaches the hydropower potential was computed from channel slope and mean annual discharge. In large areas there is a lack of discharge observations. Therefore, an annual water balance model was used to simulate discharge. The model domain covers 5 Mio km², including e.g. the Niger, Volta, and Senegal River basins. The model was calibrated with observed data of 410 gauges, using precipitation and potential evapotranspiration data as inputs. Historic variations of observed annual discharge between 1950 and 2010 are simulated well by the model. As hydropower plants are investments with a lifetime of several decades we also assessed possible changes in future discharge due to climate change. To this end the water balance model was driven with bias-corrected climate projections of 15 Regional Climate Models for two emission scenarios of the CORDEX-Africa ensemble. The simulation results for the river network were up-scaled to sub-areas and national summaries. This information gives a regional quantification of the hydropower potential, expected climate change impacts, as well as a regional classification for general suitability (or non-suitability) of hydropower plant size - from small-scale to large projects.

  8. Hybrid Gravimetry for the Monitoring of Water Storage Changes in the Critical Zone of West Africa

    NASA Astrophysics Data System (ADS)

    Hector, B.; Hinderer, J.; Séguis, L.; Calvo, M.; Pfeffer, J.

    2015-12-01

    Time-lapse gravimetry is known to be a powerful tool to monitor mass redistributions near the Earth's surface and hence is of interest in various fields (volcanology, hydrology, glaciology, geothermics, C02 sequestration). Hybrid gravimetry relies on the combined use of different types of instruments measuring the earth's gravity changes i.e. relative spring gravimeters (RG) and superconducting gravimeters (SG), as well as ballistic absolute gravimeters (AG) in a specific study. We show here that hybrid gravimetry is able to provide new constraints on underground water storage changes. We will focus on two special cases in West Africa which were investigated in the frame of the GHYRAF (Gravity and Hydrology in Africa) project: one is located in the semi-arid Sahelian zone in Wankama (Niger) and another one in Djougou (Benin) in the humid, hard-rock basement zone. In Wankama, both time-lapse AG and RG are available. In an innovative field survey during 3 months of the rainy season in 2009, we merged relative microgravimetry on a network of 12 stations, magnetic resonance soundings, and hydrological measurements to evaluate both surface and subsurface water storage variations. We show that most of the gravity variations originate from heterogeneities in the vadose zone highlighting the potential of time lapse microgravity surveys for detecting intraseasonal water storage variations in the critical zone. In Djougou, we will present the hydrology results coming from the use of the hybrid gravimetry approach based on a continuous record of a GWR SG installed since 2010 complemented with FG5 AG episodic measurements (4 times a year between 2008 and 2011 then yearly). In addition we also set up repeated micro-gravimetric measurements with a Scintrex CG5 RG on a dense network (more than 100 surveys and 15 stations) around the base station. The continuous SG record allows to bring additional insight on the space and time variable gravity (and hence water storage changes) in

  9. Cost-Effectiveness of Antivenoms for Snakebite Envenoming in 16 Countries in West Africa

    PubMed Central

    Hamza, Muhammad; Idris, Maryam A.; Maiyaki, Musa B.; Lamorde, Mohammed; Chippaux, Jean-Philippe; Warrell, David A.; Kuznik, Andreas; Habib, Abdulrazaq G.

    2016-01-01

    Background Snakebite poisoning is a significant medical problem in agricultural societies in Sub Saharan Africa. Antivenom (AV) is the standard treatment, and we assessed the cost-effectiveness of making it available in 16 countries in West Africa. Methods We determined the cost-effectiveness of AV based on a decision-tree model from a public payer perspective. Specific AVs included in the model were Antivipmyn, FAV Afrique, EchiTab-G and EchiTab-Plus. We derived inputs from the literature which included: type of snakes causing bites (carpet viper (Echis species)/non-carpet viper), AV effectiveness against death, mortality without AV, probability of Early Adverse Reactions (EAR), likelihood of death from EAR, average age at envenomation in years, anticipated remaining life span and likelihood of amputation. Costs incurred by the victims include: costs of confirming and evaluating envenomation, AV acquisition, routine care, AV transportation logistics, hospital admission and related transportation costs, management of AV EAR compared to the alternative of free snakebite care with ineffective or no AV. Incremental Cost Effectiveness Ratios (ICERs) were assessed as the cost per death averted and the cost per Disability-Adjusted-Life-Years (DALY) averted. Probabilistic Sensitivity Analyses (PSA) using Monte Carlo simulations were used to obtain 95% Confidence Intervals of ICERs. Results The cost/death averted for the 16 countries of interest ranged from $1,997 in Guinea Bissau to $6,205 for Liberia and Sierra Leone. The cost/DALY averted ranged from $83 (95% Confidence Interval: $36-$240) for Benin Republic to $281 ($159–457) for Sierra-Leone. In all cases, the base-case cost/DALY averted estimate fell below the commonly accepted threshold of one time per capita GDP, suggesting that AV is highly cost-effective for the treatment of snakebite in all 16 WA countries. The findings were consistent even with variations of inputs in 1—way sensitivity analyses. In addition

  10. Probabilistic Impact Assessment of Domestic Rainwater Harvesting in Urban Slums: West Africa Case Study

    NASA Astrophysics Data System (ADS)

    Cowden, J. R.; Watkins, D. W.; Mihelcic, J. R.; Fry, L. M.

    2007-12-01

    Urban populations now exceed rural populations worldwide, creating unique challenges in providing basic services, especially in developing countries where informal or illegal settlements grow in peri-urban areas. West Africa is an acute example of the problems created by rapid urban growth, with high levels of urban poverty and low water and sanitation access rates. Although considerable effort has been made in providing improved water access and urban services to slum communities, research indicates that clean water access rates are not keeping up with urbanization rates in several areas of the world and that rapidly growing slum communities are beginning to overwhelm many prior water improvements projects. In the face of these challenges, domestic rainwater harvesting is proposed as a technologically appropriate and economically viable option for enhancing water supplies to urban slum households. However, assessing the reliability, potential health impacts, and overall cost-effectiveness of these systems on a regional level is difficult for several reasons. First, long daily rainfall records are not readily available in much of the developing world, including many regions of sub-Saharan Africa. Second, significant uncertainties exist in the relevant cost, water use, and health data. Third, to estimate the potential future impacts at the regional scale, various global change scenarios should be investigated. Finally, in addition to these technical challenges, there is also a need to develop relatively simple and transparent assessment methods for informing policy makers. A procedure is presented for assessment of domestic rainwater harvesting systems using a combination of scenario, sensitivity, and trade-off analyses. Using data from West Africa, simple stochastic weather models are developed to generate rainfall sequences for the region, which are then used to estimate the reliability of providing a range of per capita water supplies. Next, a procedure is

  11. Etiology of urethral discharge in West Africa: the role of Mycoplasma genitalium and Trichomonas vaginalis.

    PubMed Central

    Pépin, J.; Sobéla, F.; Deslandes, S.; Alary, M.; Wegner, K.; Khonde, N.; Kintin, F.; Kamuragiye, A.; Sylla, M.; Zerbo, P. J.; Baganizi, E.; Koné, A.; Kane, F.; Mâsse, B.; Viens, P.; Frost, E.

    2001-01-01

    OBJECTIVE: To determine the etiological role of pathogens other than Neisseria gonorrhoeae and Chlamydia trachomatis in urethral discharge in West African men. METHODS: Urethral swabs were obtained from 659 male patients presenting with urethral discharge in 72 primary health care facilities in seven West African countries, and in 339 controls presenting for complaints unrelated to the genitourinary tract. Polymerase chain reaction analysis was used to detect the presence of N. gonorrhoeae, C. trachomatis, Trichomonas vaginalis, Mycoplasma genitalium, and Ureaplasma urealyticum. FINDINGS: N. gonorrhoeae, T. vaginalis, C. trachomatis, and M. genitalium--but not U. urealyticum--were found more frequently in men with urethral discharge than in asymptomatic controls, being present in 61.9%, 13.8%, 13.4% and 10.0%, respectively, of cases of urethral discharge. Multiple infections were common. Among patients with gonococcal infection, T. vaginalis was as frequent a coinfection as C. trachomatis. M. genitalium, T. vaginalis, and C. trachomatis caused a similar clinical syndrome to that associated with gonococcal infection, but with a less severe urethral discharge. CONCLUSIONS: M. genitalium and T. vaginalis are important etiological agents of urethral discharge in West Africa. The frequent occurrence of multiple infections with any combination of four pathogens strongly supports the syndromic approach. The optimal use of metronidazole in flowcharts for the syndromic management of urethral discharge needs to be explored in therapeutic trials. PMID:11242818

  12. A new inventory for two-wheel vehicle emissions in West Africa for 2002

    NASA Astrophysics Data System (ADS)

    Assamoi, Eric-Michel; Liousse, Catherine

    2010-10-01

    Rather surprisingly, urban atmospheric particulate levels in West Africa compare with measured concentrations in Europe and Asia megacities (Liousse, C., Galy-Lacaux, C., Assamoi, E.-M., Ndiaye, A., Diop, B., Cachier, H., Doumbia, T., Gueye, P., Yoboue, V., Lacaux, J.-P., Guinot, B., Guillaume, B., Rosset, R., Castera, P., Gardrat, E., Zouiten, C., Jambert, C., Diouf, A., Koita, O., Baeza, A., Annesi-Maesano, I., Didier, A., Audry, S., Konare, A., 2009. Integrated Focus on West African Cities (Cotonou, Bamako, Dakar, Ouagadougou, Abidjan, Niamey): Emissions, Air Quality and Health Impacts of Gases and Aerosols. Third International AMMA Conference on Predictability of the West African Moosoon Weather, Climate and Impacts. Ouagadougou, Burkina Faso. July 20-24). This pollution mainly derives from road traffic emissions with, in some capitals (e.g. Cotonou), the strong contribution of two-wheel vehicles. Two key questions arise: are presently available emission inventories (e.g. Junker, C., Liousse, C., 2008. A global emission inventory of carbonaceous aerosol from historic records of fossil fuel and biofuel consumption for the period 1860-1997. Atmospheric Chemistry Physics, 8, 1-13; Bond, T.C., Streets, D.G., Yarber, K.F., Nelson, S.M., Woo, J.H., Klimont, Z., 2004. A technology-based global inventory of black and organic carbon emissions from combustion. Journal of Geophysical Research, 1009, D14203, DOI:10.1029/2003JD003697) able to account for these emissions? And, if not, how can we remedy this? The aim of this paper is to develop a methodology to estimate emissions produced by two-wheel vehicles in West Africa for 2002 in a context where reliable information is hardly available. Fuel consumption ratios between two-wheel engines (in this work) and all vehicles issued from UN database ( http://data.un.org/Data.aspx?d=EDATA&f=cmID%3aMO%3btrID%3a1221) are as high as 169%, 264% and 628%, for Burkina Faso, Mali and Chad respectively, indicating that this global

  13. 'FAN the SUN brighter': fortifying Africa nutritionally (FAN) - the role of public private partnership in scaling up nutrition (SUN) in West Africa.

    PubMed

    Sablah, Mawuli; Baker, Shawn K; Badham, Jane; De Zayas, Alfred

    2013-11-01

    The scaling up nutrition (SUN) policy framework requires extensive public–private partnership (PPP). Malnutrition is multi-dimensional and should engage multi-sectoral platforms. The SUN policy however did not fully embrace the dynamics of harnessing PPP. The objectives of the present paper are to highlight the reasons for the apprehension around PPP and illustrate how effective coordination of PPP in West Africa has contributed to implementing large-scale food fortification with micronutrients as a complementary nutrition intervention. The experience of Helen Keller International (HKI) in scaling up food fortification was emphasised with understanding of the factors contributing to indifference by the international community to private sector contribution to SUN. The roles of different stakeholders in a PPP are elucidated and the process linked to who, why and how to engage. The private sector provides direct nutrition services while the public sector creates the enabling environment for the private sector to thrive on social values. Through this approach fortified vegetable oil and wheat flour are now reaching over 70% of the population in West Africa. As a neutral broker HKI coordinated and facilitated dialogue among the different stakeholders. The core competencies of each stakeholder were harnessed and each partner was held accountable. It concludes that multi-sectoral relationship must be transparent, equitable and based on shared mutual interests. The rules and values of PPP offer opportunities for SUN.

  14. West Africa - A Safe Haven for Frogs? A Sub-Continental Assessment of the Chytrid Fungus (Batrachochytrium dendrobatidis)

    PubMed Central

    Penner, Johannes; Adum, Gilbert B.; McElroy, Matthew T.; Doherty-Bone, Thomas; Hirschfeld, Mareike; Sandberger, Laura; Weldon, Ché; Cunningham, Andrew A.; Ohst, Torsten; Wombwell, Emma; Portik, Daniel M.; Reid, Duncan; Hillers, Annika; Ofori-Boateng, Caleb; Oduro, William; Plötner, Jörg; Ohler, Annemarie; Leaché, Adam D.; Rödel, Mark-Oliver

    2013-01-01

    A putative driver of global amphibian decline is the panzootic chytrid fungus Batrachochytrium dendrobatidis (Bd). While Bd has been documented across continental Africa, its distribution in West Africa remains ambiguous. We tested 793 West African amphibians (one caecilian and 61 anuran species) for the presence of Bd. The samples originated from seven West African countries - Bénin, Burkina Faso, Côte d'Ivoire, Ghana, Guinea, Liberia, Sierra Leone - and were collected from a variety of habitats, ranging from lowland rainforests to montane forests, montane grasslands to humid and dry lowland savannahs. The species investigated comprised various life-history strategies, but we focused particularly on aquatic and riparian species. We used diagnostic PCR to screen 656 specimen swabs and histology to analyse 137 specimen toe tips. All samples tested negative for Bd, including a widespread habitat generalist Hoplobatrachus occipitalis which is intensively traded on the West African food market and thus could be a potential dispersal agent for Bd. Continental fine-grained (30 arc seconds) environmental niche models suggest that Bd should have a broad distribution across West Africa that includes most of the regions and habitats that we surveyed. The surprising apparent absence of Bd in West Africa indicates that the Dahomey Gap may have acted as a natural barrier. Herein we highlight the importance of this Bd-free region of the African continent - especially for the long-term conservation of several threatened species depending on fast flowing forest streams (Conraua alleni (“Vulnerable”) and Petropedetes natator (“Near Threatened”)) as well as the “Critically Endangered” viviparous toad endemic to the montane grasslands of Mount Nimba (Nimbaphrynoides occidentalis). PMID:23426141

  15. Precipitation interannual variability and predictions for West Africa from the National Multi-Model Ensemble dataset

    NASA Astrophysics Data System (ADS)

    Thiaw, W. M.

    2013-12-01

    The ability of coupled climate models from the national multi-model ensemble (NMME) dataset to reproduce the basic state and interannual variability of precipitation in West Africa and associated teleconnections is examined. The analysis is for the period 1982-2010 for most of the models, which corresponds to the NMME hindcast period, except for the CFS version 1 (CFSv1) which covers the period 1981-2009. The satellite based CPC African Rainfall Climatology (ARC2) data is used as proxy for observed rainfall and to validate the models. We examine rainfall patterns throughout the year. Models are able to reproduce the north-south migration of precipitation from winter and spring when the area of maximum precipitation is located in Central Africa and the Gulf of Guinea region to the summer when it is in northern Sub-Saharan Africa, and the later return to the south. Models also appropriately place precipitation over the Gulf of Guinea region during the equinoxes in MAM and OND. However, there are considerable differences in the representation of the intensities and locations of the rainfall. Three of the models including the two versions of the NCEP CFS and the NASA models also have a systematic dry (wet) bias over the Sahel (Gulf of Guinea region) during the summer rainfall season, while the others show alternating wet and dry biases across West Africa. All models have spatially averaged values of standard deviation lower than that observed. Models are also able to reproduce to some extent the main features of the precipitation variability maximum, but again with deficiencies in the amplitudes and locations. The areas of highest variability are generally depicted, but there are significant differences among the models, and even between the two versions of the CFS. Teleconnections in the models are investigated by first conducting an EOF in the precipitation anomaly fields and then perform a regression of the first or second EOF time series onto the global SST

  16. Moko Jumbies: Dancing Spirits from Africa

    ERIC Educational Resources Information Center

    Bennett, S. A.; Phillips, Claire; Moore, Natalie

    2009-01-01

    The original Moko Jumbie was a spirit dancer from West Africa. "Moko" is a West African word that refers to gods and "Jumbie" means ghost. In West Africa, Moko Jumbies are known to kidnap and eat disobedient children, steal dreams and see into evildoers' hearts and terrorize them. They walk through villages on 10- to…

  17. [An approach to food consumption in an urban environment. The case of west Africa].

    PubMed

    Ag Bendech, M; Gerbouin-Rerolle, P; Chauliac, M; Malvy, D

    1996-01-01

    West Africa has undergone rapid economic and political changes during the last 20 years. After the failure of economic policies implemented since independence, programs for structural adjustment have strongly influenced the economy. Food problems affect each country differently. The Sahel has experienced food shortages and starvation whereas in forested countries the food supply has remained stable. Nevertheless, food policies have not succeeded in contributing to urban and rural development. The rate of urbanization in west Africa is generally low but the rate of urban population growth is particularly high, much more than the growth rates of industry and infrastructure. Although metropolitan areas are affected by poverty, they offer more hope and opportunities than rural areas. Urban markets have expanded and diversified as social differences have also increased and contributed to changes in consumption structure. Urban growth has contributed to the increase of imported food: this is indicated by both the strong dependency and the change of food habits towards western food patterns. Recently however, west African urban dwellers are still preferring local items if they are affordable. When imported products are used, they are integrated within a stable meal plan consisting of a single dish with a base and a sauce, which is typical of African food preparation. Surveys of consumption-budgets are still only available on a national scale. These can provide accurate information about food consumption patterns of families, particularly for significant trends. However, they do not provide information about the dynamics of food consumption, neither for urban areas or the individual. Now a significant proportion of individual food consumption occurs outside of the home, mainly with food provided by street vendors. This new consumption habit is a response to the urban food crisis. Consumption of street-vendor-food comprises one component but this cannot be dissociated from

  18. Sustainable Development of Research Capacity in West Africa based on the GLOWA Volta Project

    NASA Astrophysics Data System (ADS)

    Liebe, Jens R.; Rogmann, Antonio; Falk, Ulrike; Amisigo, Barnabas; Nyarko, Kofi; Harmsen, Karl; Vlek, Paul L. G.

    2010-05-01

    The Sustainable Development of Research Capacity (SDRC) in West Africa is an 18 month project, funded by the German Ministry of Education and Research, to strengthen the research capacity, give access to data and models, and to support the establishment of the newly formed Volta Basin Authority. The SDRC project largely builds on the results and models developed in the framework of the GLOWA Volta Project (GVP), a nine-year, interdisciplinary research project (May 2000 - May 2009). The GVP's central objectives were to analyze the physical and socio-economic determinants of the hydrological cycle in the Volta Basin in the face of global change, and to develop scientifically sound decision support resources. Another major achievement of GVP was the extensive capacity building. Of the 81 participating students (57 Ph.D.'s), 44 originated from West Africa, and 85% of the West African graduates returned to their home countries. The SDRC makes use of the wide range of research results and decision support tools developed in the course of the GVP. It is based on three columns: I. knowledge transfer and strengthening of human capacity, which focus on a training on the modeling of the onset of the rainy season, hydrological, economic, and hydro-economic modeling, and training of geospatial database managers; II. strengthening of infrastructural research capacity through the support of a research instrumentation network through the operation and transfer of a weather station network, a network of tele-transmitted stream gauges; and III. the transfer of a publicly accessible online Geoportal for the dissemination of various geospatial data and research results. At the center of the SDRC effort is the strengthening of the Volta Basin Authority, a river basin authority with a transnational mandate, especially through the transfer of the Geoportal, and the associated training and promotion efforts. The Geoportal is an effort to overcome the data scarcity previously observed in

  19. The nutrition and health impact of cash cropping in west Africa: a historical perspective.

    PubMed

    Brun, T A

    1991-01-01

    The impact of cash cropping in West Africa cannot be isolated from its social and historical background. Among the many changes brought to West African economies by cash cropping since the beginning of the century, the present document shows how the extension of trade with European merchants and colonizers created new sets of values and criteria for wealth. Food crops gradually lost their prominent cultural and economics roles to the benefit of export crops or goods. Traditional systems of agricultural production were profoundly disrupted by military actions. They imposed colonial rule and control of trade of tropical crops and goods. Forced labor and compulsory (poorly paid) work assignments were instituted for private and public enterprises: construction of roads, railways, public buildings and plantations. The main justification was the need for cheap labor to cultivate, transport and build roads for the extraction of raw materials. This in turn caused massive migrations from countries such as Burkina Faso (Upper Volta) to Ivory Coast. Cash cropping made systematic collection of taxes possible. An imposition on a per capita basis became the rule and the major incentive of small farmers to engage in commercial farming. Cash cropping made also possible extensive monetarization of West Africa. This results in both favorable and unfavorable effects on the quality of the diet. In profoundly disrupted traditional societies, the diffusion of new consumption patterns was easier and faster. It led to massive food imports of wheat, rice, sugar, alcohol, etc. Cash cropping was (and still is) practiced as a 'mining' agriculture, exhausting soils and deteriorating their fertility for extended periods of time. In the Sudanian and Sahelian zones cash cropping conflicted with the cultivation of grains because peak demands for labor were similar. Therefore, millet and sorghum production declined. Cash cropping was developed in response to the need of European economies for

  20. An overview of the nutrition transition in West Africa: implications for non-communicable diseases.

    PubMed

    Bosu, William K

    2015-11-01

    The nutrition landscape in West Africa has been dominated by the programmes to address undernutrition. However, with increasing urbanisation, technological developments and associated change in dietary patterns and physical activity, childhood and adult overweight, and obesity are becoming more prevalent. There is an evidence of increasing intake of dietary energy, fat, sugars and protein. There is low consumption of fruit and vegetables universally in West Africa. Overall, the foods consumed are predominantly traditional with the component major food groups within recommended levels. Most of the West African countries are at the early stages of nutrition transition but countries such as Cape Verde, Ghana and Senegal are at the latter stages. In the major cities of the region, children consume energy-dense foods such as candies, ice cream and sweetened beverages up to seven times as frequently as fruit and vegetables. Adult obesity rates have increased by 115 % in 15 years since 2004. In Ghana, the prevalence of overweight/obesity in women has increased from 12·8 % in 1993 to 29·9 % in 2008. In Accra, overweight/obesity in women has increased from 62·2 % in 2003 to 64·9 % in 2009. The age-standardised proportion of adults who engage in adequate levels of physical activity ranges from 46·8 % in Mali to 94·7 % in Benin. The lingering stunting in children and the rising overweight in adults have resulted to a dual burden of malnutrition affecting 16·2 % of mother-child pairs in Cotonou. The prevalence of hypertension has been increased and ranges from 17·6 % in Burkina Faso to 38·7 % in Cape Verde. The prevalence is higher in the cities: 40·2 % in Ougadougou, 46·0 % in St Louis and 54·6 % in Accra. The prevalence of diabetes ranges from 2·5 to 7·9 % but could be as high as 17·9 % in Dakar, Senegal. The consequences of nutrition transition are not only being felt by the persons in the high socioeconomic class, but also in cities such as Accra and

  1. Dynamic Topography in the Oceanic Realm of West Africa, India, and the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Hoggard, M. J.; Roberts, G.; White, N. J.

    2012-12-01

    It is generally agreed that convection in the mantle can generate vertical motions at the Earth's surface. Consequently, the recorded history of subsidence and uplift holds important clues about mantle convection. We use the well-established relationship between seafloor subsidence and age to map present-day residual depth anomalies in the oceanic realm. This map yields estimates of the spatial variation of dynamic topography, providing care is taken to rule out other potential causes of subsidence or uplift such as flexure adjacent to seamounts and subduction zones. Global analysis indicates that anomalies typically vary between ±1 km, over wavelengths of ~1000 km. This analysis of residual topography is concentrated on the oldest oceanic crust that abuts continental margins in order to provide a leg up onto the continents, where measuring absolute values of dynamic topography is considerably more complicated. Here we begin by looking at three areas in more detail - the west coast of Africa, India and the Gulf of Mexico. Residual depths along the west coast of Africa capture two full wavelengths of dynamic topography, which correlate well with the long-wavelength free air gravity anomaly. To constrain the temporal evolution of dynamic topography, we focus on regions such as the Gulf of Mexico which is currently drawn-down by ~2 km at its centre. Backstripping stratigraphic data from wells implies the majority of the anomalous subsidence has occurred in the last ~15 Ma. The east coast of India shows a drawdown of 2 km beneath the Bengal fan and the development of this anomaly is clearly recorded in the transition from progradational to aggradational behaviour within the margin's clinoform architecture. Analysis of adjacent river profiles indicates recent onshore uplift has provided high quantities of clastic detritus that have been deposited on the margin. Oceanic residual depths along the west African margin overlain by the long wavelength filtered free air

  2. Understanding the impact of land use change on climate in West Africa

    NASA Astrophysics Data System (ADS)

    Taylor, C. M.; Lambin, E. F.; Stephenne, N.; Oregan, D. P.; Harding, R. J.

    2003-04-01

    The Sahel has experienced a prolonged period of below average rainfall since the 1960s, and a number of studies have linked this to anthropogenic changes in vegetation. Previous numerical modelling experiments have shown that taking locally observed vegetation changes and extrapolating them over the entire region results in substantial reductions in rainfall. In fact, the intensity and geographical extent of actual vegetation change over recent decades are not well known. In this study, we present the sensitivity of the West African climate simulated by the Met Office/Hadley Centre Atmospheric General Circulation Model to more realistic estimates of land cover change. In the Sahel region, estimates are generated by a dynamic simulation model of land use change. This simulates the key processes associated with changing human and livestock populations, urbanisation, commercialisation of crop production and climate variability. In the tropical belt of West and Central Africa, simple deforestation scenarios are adopted, based on the Forestry Research Assessment of 2000. The sensitivity of the climate to land use is compared with simulations using global sea surface temperature patterns from extreme years. Additional simulations are performed which take into account the natural variability in biomass associated with climatic anomalies. The relative impacts of each of these factors on past and future climate in the region will be discussed.

  3. Delayed Closure of Giant Omphaloceles in West Africa: Report of Five Cases

    PubMed Central

    El Ezzi, Oumama; Bossou, Raymond; Reinberg, Olivier; Maurer, Sabine Vasseur; Roessingh, Anthony de Buys

    2017-01-01

    Giant omphalocele (GO) management is controversial and not easy. Conservative management at birth and delayed surgical closure is usually mandatory. Postponed surgery may be challenging and carry the risk of intensive care treatment. We report on five children who were treated in our department for GO between 2000 and 2010. Initially, the patients were managed conservatively in West Africa. Delayed closure of the ventral hernia was performed in Switzerland after patient transfer through a nongovernmental organization. Fascial closure was performed at the median age of 23 months. Median diameter of the hernias was 10 × 10 cm ranging from 10 × 8 cm to 24 × 15 cm. Four (80%) patients had associated anomalies. Three children needed mechanical ventilation in the intensive care unit after surgery. Median hospitalization was 19 days. Complications were seen in two patients. The follow-up showed no recurrence of ventral hernia. There was no mortality. This report shows that conservative management of a GO at birth with delayed closure of the ventral hernia after transferring the patients to a European center is a safe approach for West African children and avoids life-threatening procedures. Delayed closure of a GO may be nevertheless challenging everywhere. PMID:28352500

  4. Seasonal Variations of Water, Energy, and Carbon Fluxes Across a Moisture Gradient in West Africa

    NASA Astrophysics Data System (ADS)

    Smith, D.; Baker, I. T.; Denning, S.; Stockli, R.; Orescanin, B.

    2013-12-01

    While grasslands make up nearly 40% of Earth's land surface, many areas remain understudied and under observed. Particularly, tropical grasslands are generally less researched sites due to the remoteness of their location. Model output and satellite data have become key resources when describing and analyzing the ecological processes occurring in these areas. In this project, the Simple Biosphere Model (SiB) and fluorescence data are used alongside each other to summarize the productivity both seasonally and annually in several grassland sites in West Africa. While SiB interpreted the overall meteorological processes fairly well, the model struggled to accurately describe the variations in leaf indices, including; leaf area index, fraction of photosynthetically active radiation, and fluorescence. Specifically, fluorescence data retrieved by satellite showed variability seasonally, whereas, SiB showed very little. To improve SiB's output, the phenology of each grassland site are examined and altered to create a more realistic description than what had been previously used. The adaption resulted in more accurate modeling of ecological processes in West African grasslands. Comparing the Simple Biosphere Model (SiB) to remotely sensed observations.

  5. Pleistocene refugia and genetic diversity patterns in West Africa: Insights from the liana Chasmanthera dependens (Menispermaceae)

    PubMed Central

    Schmidt, Marco; Muellner-Riehl, Alexandra Nora; Ogundipe, Oluwatoyin Temitayo; Paule, Juraj

    2017-01-01

    Processes shaping the African Guineo-Congolian rain forest, especially in the West African part, are not well understood. Recent molecular studies, based mainly on forest tree species, confirmed the previously proposed division of the western African Guineo-Congolian rain forest into Upper Guinea (UG) and Lower Guinea (LG) separated by the Dahomey Gap (DG). Here we studied nine populations in the area of the DG and the borders of LG and UG of the widespread liana species, Chasmanthera dependens (Menispermaceae) by amplified fragment length polymorphism (AFLP), a chloroplast DNA sequence marker, and modelled the distribution based on current as well as paleoclimatic data (Holocene Climate Optimum, ca. 6 kyr BP and Last Glacial Maximum, ca. 22 kyr BP). Current population genetic structure and geographical pattern of cpDNA was related to present as well as historical modelled distributions. Results from this study show that past historical factors played an important role in shaping the distribution of C. dependens across West Africa. The Cameroon Volcanic Line seems to represent a barrier for gene flow in the present as well as in the past. Distribution modelling proposed refugia in the Dahomey Gap, supported also by higher genetic diversity. This is in contrast with the phylogeographic patterns observed in several rainforest tree species and could be explained by either diverging or more relaxed ecological requirements of this liana species. PMID:28301470

  6. Climate variability and environmental stress in the Sudan-Sahel zone of West Africa.

    PubMed

    Mertz, Ole; D'haen, Sarah; Maiga, Abdou; Moussa, Ibrahim Bouzou; Barbier, Bruno; Diouf, Awa; Diallo, Drissa; Da, Evariste Dapola; Dabi, Daniel

    2012-06-01

    Environmental change in the Sudan-Sahel region of West Africa (SSWA) has been much debated since the droughts of the 1970s. In this article we assess climate variability and environmental stress in the region. Households in Senegal, Mali, Burkina Faso, Niger, and Nigeria were asked about climatic changes and their perceptions were compared across north-south and west-east rainfall gradients. More than 80% of all households found that rainfall had decreased, especially in the wettest areas. Increases in wind speeds and temperature were perceived by an overall 60-80% of households. Contrary to household perceptions, observed rainfall patterns showed an increasing trend over the past 20 years. However, August rainfall declined, and could therefore potentially explain the contrasting negative household perceptions of rainfall trends. Most households reported degradation of soils, water resources, vegetation, and fauna, but more so in the 500-900 mm zones. Adaptation measures to counter environmental degradation included use of manure, reforestation, soil and water conservation, and protection of fauna and vegetation. The results raise concerns for future environmental management in the region, especially in the 500-900 mm zones and the western part of SSWA.

  7. The quest for safe drinking water: an example from Guinea-Bissau (West Africa).

    PubMed

    Bordalo, Adriano A; Savva-Bordalo, Joana

    2007-07-01

    While humans require water for life, one-sixth of our species lives without access to safe water. In Africa, the situation is particularly acute because of global warming, the progression of the Sahara desert, civil unrest and poor governance, population growth, migration and poverty. In rural areas, the lack of adequate safe water and sanitary infrastructures leaves millions with doubtful water quality, increasing the harshness of daily life. In this paper, a pilot study was conducted during the wet season on Bolama Island (Guinea-Bissau, West Africa), a UNESCO Man and the Biosphere Reserve. Twenty-eight shallow wells, supplying water to most of the population, were sampled for microbiological, physical and chemical water quality characteristics. A ten-parameter water quality index (WQI) adapted to tropical conditions was applied to compare the different wells. About 79% of the wells showed moderate to heavy fecal contamination. From the surveyed parameters, it was found that chemical contamination was less important, although all samples were acidic, with the pH averaging 5.12+/-0.08. The WQI was 43+/-4% (0%-worst; 100%-best quality), showing that the water from the majority of wells was polluted but should be suitable for domestic use after appropriate treatment. At the onset of the wet season, diarrhea represented 11.5% of all medical cases, 92.5% of which were children aged <15. This paper suggests inexpensive steps to reduce the fecal contamination and control the pH in order to increase the potability of the well water and, concomitantly, to raise the living standards of the population in one of the poorest countries of the world.

  8. A GCM study of the response of the atmospheric water cycle of West Africa and the Atlantic to Saharan dust radiative forcing

    NASA Astrophysics Data System (ADS)

    Lau, K. M.; Kim, K. M.; Sud, Y. C.; Walker, G. K.

    2009-10-01

    The responses of the atmospheric water cycle and climate of West Africa and the Atlantic to radiative forcing of Saharan dust are studied using the NASA finite volume general circulation model (fvGCM), coupled to a mixed layer ocean. We find evidence of an "elevated heat pump" (EHP) mechanism that underlines the responses of the atmospheric water cycle to dust forcing as follow. During the boreal summer, as a result of large-scale atmospheric feedback triggered by absorbing dust aerosols, rainfall and cloudiness are enhanced over the West Africa/Eastern Atlantic ITCZ, and suppressed over the West Atlantic and Caribbean region. Shortwave radiation absorption by dust warms the atmosphere and cools the surface, while longwave has the opposite response. The elevated dust layer warms the air over West Africa and the eastern Atlantic. As the warm air rises, it spawns a large-scale onshore flow carrying the moist air from the eastern Atlantic and the Gulf of Guinea. The onshore flow in turn enhances the deep convection over West Africa land, and the eastern Atlantic. The condensation heating associated with the ensuing deep convection drives and maintains an anomalous large-scale east-west overturning circulation with rising motion over West Africa/eastern Atlantic, and sinking motion over the Caribbean region. The response also includes a strengthening of the West African monsoon, manifested in a northward shift of the West Africa precipitation over land, increased low-level westerly flow over West Africa at the southern edge of the dust layer, and a near surface westerly jet underneath the dust layer over the Sahara. The dust radiative forcing also leads to significant changes in surface energy fluxes, resulting in cooling of the West African land and the eastern Atlantic, and warming in the West Atlantic and Caribbean. The EHP effect is most effective for moderate to highly absorbing dusts, and becomes minimized for reflecting dust with single scattering albedo at 0

  9. A GCM Study of Responses of the Atmospheric Water Cycle of West Africa and the Atlantic to Saharan Dust Radiative Forcing

    NASA Technical Reports Server (NTRS)

    Lau, K. M.; Kim, K. M.; Sud, Y. C.; Walker, G. K.

    2009-01-01

    The responses of the atmospheric water cycle and climate of West Africa and the Atlantic to radiative forcing of Saharan dust are studied using the NASA finite volume general circulation model (fvGCM), coupled to a mixed layer ocean. We find evidence of an "elevated heat pump" (EHP) mechanism that underlines the responses of the atmospheric water cycle to dust forcing as follow. During the boreal summerr, as a result of large-scale atmospheric feedback triggered by absorbing dust aerosols, rainfall and cloudiness are ehanIed over the West Africa/Eastern Atlantic ITCZ, and suppressed over the West Atlantic and Caribbean region. Shortwave radiation absorption by dust warms the atmosphere and cools the surface, while longwave has the opposite response. The elevated dust layer warms the air over West Africa and the eastern Atlantic. As the warm air rises, it spawns a large-scale onshore flow carrying the moist air from the eastern Atlantic and the Gulf of Guinea. The onshore flow in turn enhances the deep convection over West Africa land, and the eastern Atlantic. The condensation heating associated with the ensuing deep convection drives and maintains an anomalous large-scale east-west overturning circulation with rising motion over West Africa/eastern Atlantic, and sinking motion over the Caribbean region. The response also includes a strengthening of the West African monsoon, manifested in a northward shift of the West Africa precipitation over land, increased low-level westerlies flow over West Africa at the southern edge of the dust layer, and a near surface westerly jet underneath the dust layer overr the Sahara. The dust radiative forcing also leads to significant changes in surface energy fluxes, resulting in cooling of the West African land and the eastern Atlantic, and warming in the West Atlantic and Caribbean. The EHP effect is most effective for moderate to highly absorbing dusts, and becomes minimized for reflecting dust with single scattering albedo at0

  10. Marine Incursion: The Freshwater Herring of Lake Tanganyika Are the Product of a Marine Invasion into West Africa

    PubMed Central

    Wilson, Anthony B.; Teugels, Guy G.; Meyer, Axel

    2008-01-01

    The spectacular marine-like diversity of the endemic fauna of Lake Tanganyika, the oldest of the African Great Lakes, led early researchers to suggest that the lake must have once been connected to the ocean. Recent geophysical reconstructions clearly indicate that Lake Tanganyika formed by rifting in the African subcontinent and was never directly linked to the sea. Although the Lake has a high proportion of specialized endemics, the absence of close relatives outside Tanganyika has complicated phylogeographic reconstructions of the timing of lake colonization and intralacustrine diversification. The freshwater herring of Lake Tanganyika are members of a large group of pellonuline herring found in western and southern Africa, offering one of the best opportunities to trace the evolutionary history of members of Tanganyika's biota. Molecular phylogenetic reconstructions indicate that herring colonized West Africa 25–50MYA, at the end of a major marine incursion in the region. Pellonuline herring subsequently experienced an evolutionary radiation in West Africa, spreading across the continent and reaching East Africa's Lake Tanganyika during its early formation. While Lake Tanganyika has never been directly connected with the sea, the endemic freshwater herring of the lake are the descendents of an ancient marine incursion, a scenario which may also explain the origin of other Tanganyikan endemics. PMID:18431469

  11. Gambian-British and Nigerian-British Children's and Families' Experiences of Migration "Back" to West Africa. Research Briefing No. 13

    ERIC Educational Resources Information Center

    Roberts-Holmes, Guy

    2013-01-01

    This research looks at the factors motivating Gambian-British and Nigerian-British parents to send their children "back" to West Africa and what this means for parents, children and families on both continents.

  12. Extensive nitrogen loss from permeable sediments off North-West Africa

    NASA Astrophysics Data System (ADS)

    Sokoll, Sarah; Lavik, Gaute; Sommer, Stefan; Goldhammer, Tobias; Kuypers, Marcel M. M.; Holtappels, Moritz

    2016-04-01

    The upwelling area off North-West Africa is characterized by high export production, high nitrate and low oxygen concentration in bottom waters. The underlying sediment consists of sands that cover most of the continental shelf. Due to their permeability sands allow for fast advective pore water transport and can exhibit high rates of nitrogen (N) loss via denitrification as reported for anthropogenically eutrophied regions. However, N loss from sands underlying naturally eutrophied waters is not well studied, and in particular, N loss from the North-West African shelf is poorly constrained. During two research cruises in April/May 2010/2011, sediment was sampled along the North-West African shelf and volumetric denitrification rates were measured in sediment layers down to 8 cm depth using slurry incubations with 15N-labeled nitrate. Areal N loss was calculated by integrating volumetric rates down to the nitrate penetration depth derived from pore water profiles. Areal N loss was neither correlated with water depth nor with bottom water concentrations of nitrate and oxygen but was strongly dependent on sediment grain size and permeability. The derived empirical relation between benthic N loss and grains size suggests that pore water advection is an important regulating parameter for benthic denitrification in sands and further allowed extrapolating rates to an area of 53,000 km2 using detailed sediment maps. Denitrification from this region amounts to 995 kt yr-1 (average 3.6 mmol m-2 d-1) which is 4 times higher than previous estimates based on diffusive pore water transport. Sandy sediments cover 50-60% of the continental shelf and thus may contribute significantly to the global benthic N loss.

  13. Vulnerability to climate change of cocoa in West Africa: Patterns, opportunities and limits to adaptation.

    PubMed

    Schroth, Götz; Läderach, Peter; Martinez-Valle, Armando Isaac; Bunn, Christian; Jassogne, Laurence

    2016-06-15

    The West African cocoa belt, reaching from Sierra Leone to southern Cameroon, is the origin of about 70% of the world's cocoa (Theobroma cacao), which in turn is the basis of the livelihoods of about two million farmers. We analyze cocoa's vulnerability to climate change in the West African cocoa belt, based on climate projections for the 2050s of 19 Global Circulation Models under the Intergovernmental Panel on Climate Change intermediate emissions scenario RCP 6.0. We use a combination of a statistical model of climatic suitability (Maxent) and the analysis of individual, potentially limiting climate variables. We find that: 1) contrary to expectation, maximum dry season temperatures are projected to become as or more limiting for cocoa as dry season water availability; 2) to reduce the vulnerability of cocoa to excessive dry season temperatures, the systematic use of adaptation strategies like shade trees in cocoa farms will be necessary, in reversal of the current trend of shade reduction; 3) there is a strong differentiation of climate vulnerability within the cocoa belt, with the most vulnerable areas near the forest-savanna transition in Nigeria and eastern Côte d'Ivoire, and the least vulnerable areas in the southern parts of Cameroon, Ghana, Côte d'Ivoire and Liberia; 4) this spatial differentiation of climate vulnerability may lead to future shifts in cocoa production within the region, with the opportunity of partially compensating losses and gains, but also the risk of local production expansion leading to new deforestation. We conclude that adaptation strategies for cocoa in West Africa need to focus at several levels, from the consideration of tolerance to high temperatures in cocoa breeding programs, the promotion of shade trees in cocoa farms, to policies incentivizing the intensification of cocoa production on existing farms where future climate conditions permit and the establishment of new farms in already deforested areas.

  14. Radiative impact of mineral dust on monsoon precipitation variability over West Africa

    SciTech Connect

    Zhao, Chun; Liu, Xiaohong; Leung, Lai-Yung R.; Hagos, Samson M.

    2011-03-01

    The radiative forcing of dust and its impact on precipitation over the West Africa monsoon (WAM) region is simulated using a coupled meteorology and aerosol/chemistry model (WRF-Chem). During the monsoon season, dust is a dominant contributor to AOD over West Africa. In the standard simulation, on 24-hour domain average, dust has a cooling effect (-6.11 W/m2) at the surface, a warming effect (6.94 W/m2) in the atmosphere, and a relatively small TOA forcing (0.83 W/m2). Dust modifies the surface energy budget and atmospheric diabatic heating and hence causes lower atmospheric cooling in the daytime but warming in the nighttime. As a result, atmospheric stability is increased in the daytime and reduced in the nighttime, leading to a reduction of late afternoon precipitation by up to 0.14 mm/hour (30%) and an increase of nocturnal and early morning precipitation by up to 0.04 mm/hour (23%) over the WAM region. Dust-induced reduction of diurnal precipitation variation improves the simulated diurnal cycle of precipitation when compared to measurements. However, daily precipitation is only changed by a relatively small amount (-0.14 mm/day or -4%). On the other hand, sensitivity simulations show that, for weaker-to-stronger absorbing dust, dust longwave warming effect in the nighttime surpasses its shortwave cooling effect in the daytime at the surface, leading to a less stable atmosphere associated with more convective precipitation in the nighttime. As a result, the dust-induced change of daily WAM precipitation varies from a significant reduction of -0.40 mm/day (-12%, weaker absorbing dust) to a small increase of 0.05 mm/day (1%, stronger absorbing dust). This variation originates from the competition between dust impact on daytime and nighttime precipitation, which depends on dust shortwave absorption. Dust reduces the diurnal variation of precipitation regardless of its absorptivity, but more reduction is associated with stronger absorbing dust.

  15. Travelers' diarrhea in West Africa and Mexico: fecal transport systems and liquid bismuth subsalicylate for self-therapy.

    PubMed

    Steffen, R; Mathewson, J J; Ericsson, C D; DuPont, H L; Helminger, A; Balm, T K; Wolff, K; Witassek, F

    1988-05-01

    The goals of this study were threefold: to compare the etiology of travelers' diarrhea in West Africa and Mexico, to evaluate two fecal transport systems for the recovery of enteropathogens, and to verify the efficacy of liquid bismuth subsalicylate (BSS) in different locations and under different entrance criteria for disease severity. The study populations consisted of 133 European tourists in West Africa and 112 American students in Mexico who had suffered from travelers' diarrhea. In 60% and 38% of the stool samples at the two study sites, similar proportions of enteropathogens were detected. A two-vial system consisting of Enteric Plus medium and polyvinyl alcohol fixative was slightly superior for identifying enteric pathogens than was a three-vial system with buffered glycerol saline, Cary-Blair medium with campylobacter antibodies, and polyvinyl alcohol fixative. In a parallel, double-blind, randomized trial, BSS significantly shortened disease duration at both study sites.

  16. North Africa

    SciTech Connect

    Nicod, M.A.

    1981-10-01

    The total area covered by petroleum rights in the six countries described in this paper increased by more than 17% in 1980 compared to 1979. Joint venture agreements were finalized for 19 blocks over 94,000 km/sup 2/ in the Algerian venture. Although official information is scarce for Algeria and Libya, seismic activity probably increased in 1980 compared to 1979. Exploration drilling activity increased with 121 wildcats drilled compared to 93 during the previous year. This effort led to 40 discoveries, a 34.5% success ratio. Chevron was especially successful in wildcatting, with 6 oil discoveries for 8 wells drilled in the interior basins of Sudan. One Moroccan discovery can be considered as a highlight: the BRPM Meskala 101 well in the Essaouira basin found an apparently large amount of gas in Triassic sandstones. This discovery deserves special attention, since the gas has been found in Triassic pays rather than in the usual Jurassic pays in the Essaouira basin. Oil production in North Africa decreased from about 13.5% in 1980, with about 3,405,000 barrels of oil per day compared to 3,939,500 barrels of oil per day in 1979. When oil output strongly decreased in Algeria (-16.4%) and Libya (-15.6%), Tunisian production peaked at 116,287 barrels of oil per day and Egypt production also peaked at 584,148 barrels of oil per day. Total gas production in 1980 strongly declined from 44%, mostly due to the decline of the Algerian gas production. 8 figures, 40 tables.

  17. Investigating GRACE Range-Rate Observations over West Africa with respect to Small-Scale Hydrological Signals

    NASA Astrophysics Data System (ADS)

    Springer, A.; Eicker, A.; Kusche, J.; Longuevergne, L.; Diekkrüger, B.; Jütten, T.

    2015-12-01

    Here, GRACE K-band range rate (KBRR) observations are analyzed for the effects from small-scale hydrological signals over West Africa including water level changes in reservoirs, extreme weather events, and water storage variability predicted by hydrological models. The presented approach, which is based on level 1B data, avoids the downward continuation and filtering process required for computing monthly gravity field solutions and, thus, enables to assess hydrological signals with a high temporal resolution and at small spatial scales. In a first step, water mass variations derived from tide gauges, altimetry, and from hydrological model output are converted into simulated KBRR observations. Secondly, these simulated observations and a number of geophysical corrections are reduced from the original GRACE K-band observations to obtain the residuals for a time span of ten years. Then, (i) the residuals are used to validate differently modeled water mass variations and (ii) extreme weather events are identified in the residuals. West Africa represents an interesting study region as it is increasingly facing exteme precipitation events and floodings. In this study, monthly and daily output from different global hydrological models is validated for their representation of long-term and short-term (daily) water storage variability over West Africa. The daily RMS of KBRR residuals ranges between 0.1 μm/s and 0.7 μm/s. Smaller residuals imply that the model is able to better explain the observations. For example, we find that in 2007 the Land Surface Discharge Model (LSDM) better agrees with GRACE range-rate observations than the Water-GAP Global Hydrology Model (WGHM) and the GLDAS-Noah land surface model. Furthermore, we confirm previous studies and show that the signal from Lake Volta is distinctly contained in the residuals. Finally, we investigate variations of other smaller reservoirs and the floodings over West Africa in June 2009 and over Benin in October 2010.

  18. DPA1*02012: A DPA1*0201-related Mhc class II allele in West Africa

    SciTech Connect

    Meyer, C.G.; May, J.; Spauke, D.; Schnittger, L.

    1994-12-31

    DNA techniques such as sequence-specific oligonucleotide probe (SSOP) hybridizations, restriction-fragment length polymorphism (RFLP) analyses, and DNA sequencing have greatly supported the characterization of Mhc class II allelic polymorphism. Here the authors describe a DPA 1 allele which has been identified in two male individuals from Liberia and Benin, West Africa, during a survey study on Mhc class II associations with the different manifestations after infection with Onchocerca volvulus. 4 refs., 1 fig.

  19. Genetically Different Highly Pathogenic Avian Influenza A(H5N1) Viruses in West Africa, 2015

    PubMed Central

    Tassoni, Luca; Fusaro, Alice; Milani, Adelaide; Lemey, Philippe; Awuni, Joseph Adongo; Sedor, Victoria Bernice; Dogbey, Otilia; Commey, Abraham Nii Okai; Meseko, Clement; Joannis, Tony; Minoungou, Germaine L.; Ouattara, Lassina; Haido, Abdoul Malick; Cisse-Aman, Diarra; Couacy-Hymann, Emmanuel; Dauphin, Gwenaelle; Cattoli, Giovanni

    2016-01-01

    To trace the evolution of highly pathogenic influenza A(H5N1) virus in West Africa, we sequenced genomes of 43 viruses collected during 2015 from poultry and wild birds in 5 countries. We found 2 co-circulating genetic groups within clade 2.3.2.1c. Mutations that may increase adaptation to mammals raise concern over possible risk for humans. PMID:27389972

  20. Assessment of undiscovered oil and gas resources of the West African Costal Province, West Africa

    USGS Publications Warehouse

    Brownfield, Michael E.; Charpentier, Ronald R.; Schenk, Christopher J.; Klett, Timothy R.; Cook, Troy A.; Pollastro, Richard M.

    2011-01-01

    The West African Coastal Province along the west African coastline recently was assessed for undiscovered, technically recoverable oil, natural gas, and natural gas liquids resources as part of the U.S. Geological Survey's USGS World Oil and Gas Assessment. Using a geology-based assessment methodology, the USGS estimated mean volumes of 3.2 billion barrels of oil, 23.63 trillion cubic feet of natural gas, and 721 million barrels of natural gas liquids.

  1. Mitochondrial DNA variability in Giraffa camelopardalis: consequences for taxonomy, phylogeography and conservation of giraffes in West and central Africa.

    PubMed

    Hassanin, Alexandre; Ropiquet, Anne; Gourmand, Anne-Laure; Chardonnet, Bertrand; Rigoulet, Jacques

    2007-03-01

    The giraffe (Giraffa camelopardalis) still survives in four countries of West and central Africa. The populations of Niger and Cameroon are generally assigned to the subspecies peralta, but those of Chad and the Central African Republic are taxonomically problematic, as they are referred to as either peralta, or antiquorum, or congoensis. In this study, a mitochondrial fragment of 1765 nucleotide sites, covering the complete cytochrome b gene, three transfer RNAs and a large part of the control region, was sequenced to assess the relationships between several populations of giraffe. The phylogenetic analyses performed on the 12 identified haplotypes indicate that northern giraffes constitute a natural group, distinct from that of southern giraffes. Surprisingly, the giraffes of Niger are found to be more closely related to the giraffes of East Africa (subspecies rothschildi and reticulata) than to those of central Africa. We conclude therefore that the subspecies peralta contains only the Niger giraffes, whereas the subspecies antiquorum includes all populations living in Cameroon, Chad, the Central African Republic, and southwestern Sudan. We suggest that the ancestor of the Nigerian giraffe dispersed from East to North Africa during the Quaternary period and thereafter migrated to its current Sahelian distribution in West Africa, in response to the development of the Sahara desert. This hypothesis implies that Lake Mega-Chad acted as a strong geographical barrier during the Holocene, preventing any contact between the subspecies peralta and antiquorum. Our study has direct implications for conservation management, as we show that no subspecies peralta is represented in any European zoos, only in Niger, with a small population of less than 200 individuals.

  2. Desert dust impacts on human health: an alarming worldwide reality and a need for studies in West Africa

    NASA Astrophysics Data System (ADS)

    de Longueville, Florence; Ozer, Pierre; Doumbia, Seydou; Henry, Sabine

    2013-01-01

    High desert dust concentrations raise concerns about adverse health effects on human populations. Based on a systematic literature review, this paper aims to learn more about the relationship between desert dust and human health in the world and to analyse the place of West Africa as a study area of interest. Papers focussing on the potential relationship between dust and health and showing quantitative analyses, published between January 1999 and September 2011, were identified using the ISI Web of Knowledge database ( N = 50). A number of adverse health effects, including respiratory, cardiovascular and cardiopulmonary diseases, are associated with dust. This survey highlights obvious dust impacts on human health independently of the study area, health outcomes and method. Moreover, it reveals an imbalance between the areas most exposed to dust and the areas most studied in terms of health effects. None of these studies has been conducted in West Africa, despite the proximity of the Sahara, which produces about half of the yearly global mineral dust. In view of the alarming results in many parts of the world (Asia, Europe, America), this paper concludes by stressing the importance of carrying out impact studies of Saharan dust in West Africa, where dust events are more frequent and intense than anywhere else.

  3. Assessing the link between Atlantic Niño 1 and drought over West Africa using CORDEX regional climate models

    NASA Astrophysics Data System (ADS)

    Adeniyi, Mojisola Oluwayemisi; Dilau, Kabiru Alabi

    2016-12-01

    The skill of Coordinated Regional Climate Downscaling Experiment (CORDEX) models (ARPEGE, CCLM, HIRHAM, RACMO, REMO, PRECIS, RegCM3, RCA, WRF and CRCM) in simulating the climate (precipitation, temperature and drought) of West Africa is determined using a process-based metric. This is done by comparing the CORDEX models' simulated and observed correlation coefficients between Atlantic Niño Index 1 (ATLN1) and the climate over West Africa. Strong positive correlation is observed between ATLN1 and the climate parameters at the Guinea Coast (GC). The Atlantic Ocean has Niño behaviours through the ATLN indices which influence the climate of the tropics. Drought has distinct dipole structure of correlation with ATLN1 (negative at the Sahel); precipitation does not have distinct dipole structure of correlation, while temperature has almost a monopole correlation structure with ATLN1 over West Africa. The magnitude of the correlation increases with closeness to the equatorial eastern Atlantic. Correlations between ATLN1 and temperature are mostly stronger than those between ATLN1 and precipitation over the region. Most models have good performance over the GC, but ARPEGE has the highest skill at GC. The PRECIS is the most skilful over Savannah and RCA over Sahel. These models can be used to downscale the projected climate at the region of their highest skill.

  4. Oxygen, hydrogen, and helium isotopes for investigating groundwater systems of the Cape Verde Islands, West Africa

    NASA Astrophysics Data System (ADS)

    Heilweil, Victor M.; Solomon, D. Kip; Gingerich, Stephen B.; Verstraeten, Ingrid M.

    2009-07-01

    Stable isotopes (δ18O, δ2H), tritium (3H), and helium isotopes (3He, 4He) were used for evaluating groundwater recharge sources, flow paths, and residence times of three watersheds in the Cape Verde Islands (West Africa). Stable isotopes indicate the predominance of high-elevation precipitation that undergoes little evaporation prior to groundwater recharge. In contrast to other active oceanic hotspots, environmental tracers show that deep geothermal circulation does not strongly affect groundwater. Low tritium concentrations at seven groundwater sites indicate groundwater residence times of more than 50 years. Higher tritium values at other sites suggest some recent recharge. High 4He and 3He/4He ratios precluded 3H/3He dating at six sites. These high 3He/4He ratios (R/Ra values of up to 8.3) are consistent with reported mantle derived helium of oceanic island basalts in Cape Verde and provided end-member constraints for improved dating at seven other locations. Tritium and 3H/3He dating shows that São Nicolau Island’s Ribeira Fajã Basin has groundwater residence times of more than 50 years, whereas Fogo Island’s Mosteiros Basin and Santo Antão Island’s Ribeira Paul Basin contain a mixture of young and old groundwater. Young ages at selected sites within these two basins indicate local recharge and potential groundwater susceptibility to surface contamination and/or salt-water intrusion.

  5. Toward a Socio-Territorial Approach to Health: Health Equity in West Africa

    PubMed Central

    Vialard, Lucie; Squiban, Clara; Fournet, Florence; Salem, Gérard; Foley, Ellen E.

    2017-01-01

    This study contributes to the literature about the effects of space and place on health by introducing a socio-territorial approach to urban health disparities in West Africa. It explores how urban spaces, specifically neighbourhoods, are shaped by social and economic relations and strategies of territorial control. We examine the potential influence of socio-territorial processes on vulnerability to disease, access to medical care, healthscapes, and illness experiences. Our research was conducted in Senegal and relied on a mixed methods design. We identified four neighbourhoods that represent the socio-spatial heterogeneity of the city of Saint-Louis and utilized the following methods: geographic and anthropological field research, household surveys, health knowledge and behaviour surveys, clinical exams, and illness interviews. Our results highlight the socio-territorial processes at work in each neighbourhood, clinical findings on three health measures (overweight, high blood pressure, and hyperglycaemia) and health experiences of individuals with hypertension or type II diabetes. We found significant differences in the prevalence of the three health measures in the study sites, while experiences managing hypertension and diabetes were similar. We conclude that a socio-territorial approach offers insight into the complex constellation of forces that produce health disparities in urban settings. PMID:28117751

  6. IASI-derived Surface Temperature Under Dusty Conditions: Application to the West Africa Region.

    NASA Astrophysics Data System (ADS)

    Mechri, Rihab; Capelle, Virginie; Chedin, Alain

    2016-04-01

    Giving access to energy and water budgets, Surface Temperature (ST) is considered as a key variable for a wide range of applications in particular for meteorology and climatology. An accurate knowledge of this variable should significantly improve the monitoring of numerous atmospheric and surface processes as well as their interactions. Even-though satellite sensors bring ST global fields at different spatial and temporal scales, the accuracy of these products is still questionable especially over land or for complex atmospheric conditions (presence of clouds, of aerosols, etc.). At LMD, the ST is determined through the simultaneous "Look-up-Table" inversion of satellite METOP/IASI radiances in terms of Aerosol Optical Depth (AOD), dust layer mean altitude and surface temperature . The main aim of this work is to validate IASI ST product and to analyze its spatial and temporal variability, in particular in the presence of dust aerosols. This approach has been first applied to the West Africa region. The accuracy of this ST product will be assessed in terms of bias and standard deviation against ST products from ECMWF forecast, from other satellite products (MODIS AQUA/TERRA, AATSR,…) and from in-situ measurements for different periods ranging from July 2007 to today according to the availability of these validation data.

  7. Microcredit in West Africa: how small loans make a big impact on poverty.

    PubMed

    Gbezo, B E

    1999-01-01

    This article examines the impact of microfinancing schemes in West Africa and the role of the International Labor Organization (ILO) in their development. Microfinancing or microcredit schemes are meant to create the kind of jobs that can keep households severely hit by the economic crisis afloat. They affect not only the financial, but also the agricultural, crafts, financing of social economy, and social protection sectors of the society. Thus, they contribute to improved access to basic social, health and family planning services and to drinking water. The challenge then, is for institutes to adopt microfinancing and to reach out to more than 100 million families in the region. To realize this, nongovernmental organizations are setting up as veritable microfinancing institutions, which are able to realize the resulting benefits so as to be economically viable. In the context of its role in the development of microfinancing schemes, ILO manages a portfolio of technical cooperation and research projects aimed at identifying and removing constraints in the access to credit, savings, insurance, and other financial services through its Social Finance Unit. In addition, ILO is promoting women's entrepreneurship through the International Small Enterprise Programme and the International Programme on More and Better Jobs for Women.

  8. Occurrence of Emerging Micropollutants in Water Systems in Gauteng, Mpumalanga, and North West Provinces, South Africa

    PubMed Central

    Wanda, Elijah M. M.; Nyoni, Hlengilizwe; Mamba, Bhekie B.; Msagati, Titus A. M.

    2017-01-01

    The ubiquitous occurrence of emerging micropollutants (EMPs) in water is an issue of growing environmental-health concern worldwide. However, there remains a paucity of data regarding their levels and occurrence in water. This study determined the occurrence of EMPs namely: carbamazepine (CBZ), galaxolide (HHCB), caffeine (CAF), tonalide (AHTN), 4-nonylphenol (NP), and bisphenol A (BPA) in water from Gauteng, Mpumalanga, and North West provinces, South Africa using comprehensive two-dimensional gas chromatography coupled to high resolution time-of-flight mass spectrometry (GCxGC-HRTOFMS). Kruskal-Wallis test and ANOVA were performed to determine temporal variations in occurrence of the EMPs. Principal component analysis (PCA) and Surfer Golden Graphics software for surface mapping were used to determine spatial variations in levels and occurrence of the EMPs. The mean levels ranged from 11.22 ± 18.8 ng/L for CAF to 158.49 ± 662 ng/L for HHCB. There was no evidence of statistically significant temporal variations in occurrence of EMPs in water. Nevertheless, their levels and occurrence vary spatially and are a function of two principal components (PCs, PC1 and PC2) which controlled 89.99% of the variance. BPA was the most widely distributed EMP, which was present in 62% of the water samples. The detected EMPs pose ecotoxicological risks in water samples, especially those from Mpumalanga province. PMID:28098799

  9. Groundwater arsenic contamination in Burkina Faso, West Africa: Predicting and verifying regions at risk.

    PubMed

    Bretzler, Anja; Lalanne, Franck; Nikiema, Julien; Podgorski, Joel; Pfenninger, Numa; Berg, Michael; Schirmer, Mario

    2017-04-15

    Arsenic contamination in groundwater from crystalline basement rocks in West Africa has only been documented in isolated areas and presents a serious health threat in a region already facing multiple challenges related to water quality and scarcity. We present a comprehensive dataset of arsenic concentrations from drinking water wells in rural Burkina Faso (n=1498), of which 14.6% are above 10μg/L. Included in this dataset are 269 new samples from regions where no published water quality data existed. We used multivariate logistic regression with arsenic measurements as calibration data and maps of geology and mineral deposits as independent predictor variables to create arsenic prediction models at concentration thresholds of 5, 10 and 50μg/L. These hazard maps delineate areas vulnerable to groundwater arsenic contamination in Burkina Faso. Bedrock composed of schists and volcanic rocks of the Birimian formation, potentially harbouring arsenic-containing sulphide minerals, has the highest probability of yielding groundwater arsenic concentrations >10μg/L. Combined with population density estimates, the arsenic prediction models indicate that ~560,000 people are potentially exposed to arsenic-contaminated groundwater in Burkina Faso. The same arsenic-bearing geological formations that are positive predictors for elevated arsenic concentrations in Burkina Faso also exist in neighbouring countries such as Mali, Ghana and Ivory Coast. This study's results are thus of transboundary relevance and can act as a trigger for targeted water quality surveys and mitigation efforts.

  10. Aircraft measurements of biomass burning aerosol over West Africa during DABEX

    NASA Astrophysics Data System (ADS)

    Johnson, B. T.; Osborne, S. R.; Haywood, J. M.; Harrison, M. A. J.

    2008-12-01

    This paper investigates the properties of biomass burning aerosols over West Africa using data from the UK FAAM aircraft during the Dust and Biomass-burning Experiment (DABEX). Aged biomass burning aerosols were widespread across the region, often at altitudes up to 4 km. Fresh biomass burning aerosols were observed at low altitudes by flying through smoke plumes from agricultural fires. The aircraft measured aerosol size distributions, optical properties, and vertical distributions. Single scattering albedo varied from 0.73 to 0.93 (at 0.55 μm) in aerosol layers dominated by biomass burning aerosol. We attribute much of this variation to the variable proportion of mineral dust and biomass burning aerosol. We estimate the single scattering albedo of aged biomass burning aerosol to be around 0.81 with an instrumental uncertainty of ±0.05. External mixing, and possibly internal mixing, between the biomass burning aerosol and mineral dust presents an additional source of uncertainty in this estimate. The size distributions of biomass burning aerosols were dominated by particles with radii smaller than 0.35 μm. A 20% increase of count mean radius was observed when contrasting fresh and aged biomass burning aerosols, accompanied by changes in the shape of the size distribution. These changes suggest growth by coagulation and condensation. Extinction coefficients, asymmetry parameters, and Angstrom exponents are calculated from Mie theory, using the lognormal fits to the measured size distributions and assumed refractive indices.

  11. The economic impact of strategic risk on petroleum ventures: Examples from West Africa

    SciTech Connect

    Ethetton, L.K.; Brumbaugh, W.D.

    1995-12-31

    Strategic risks attend any and all business ventures. They arise from the nature of the particular business being pursued and the environment in which that business is being conducted. In the petroleum industry, considerable attention is devoted to quantifying technical risks, i.e., the risk of finding and producing hydrocarbons. However, strategic risks often impact economic viability more than technical asks. Accordingly, strategic risk analysis is critical to, realistically evaluating petroleum ventures in today`s turbulent business environment. While difficult to assess and quantify, strategic risks must be accorded equal status with technical risks. Competitor activity, contract terms, environmental sensitivity, political stability and market forces are typical strategic risks. A strategic risk system correlates a company`s capabilities with the quality of possible ventures. Internal strengths and weaknesses are thus matched against external opportunities and threats. This is known in the business literature as a SWOT analysis. The degree of strategic risk is then proportional to the mismatch between the SWOT elements. Such a mismatch was not recognized during exploration of the West Africa Aptian Salt Basins play in the 1980s. Angola, Congo and Gabon all contain examples where failure to consider strategic risk ultimately resulted in {open_quotes}Gambler`s Ruin{close_quotes}.

  12. Deciphering Dynamics of Recent Epidemic Spread and Outbreak in West Africa: The Case of Ebola Virus

    NASA Astrophysics Data System (ADS)

    Upadhyay, Ranjit Kumar; Roy, Parimita

    Recently, the 2014 Ebola virus (EBOV) outbreak in West Africa was the largest outbreak to date. In this paper, an attempt has been made for modeling the virus dynamics using an SEIR model to better understand and characterize the transmission trajectories of the Ebola outbreak. We compare the simulated results with the most recent reported data of Ebola infected cases in the three most affected countries Guinea, Liberia and Sierra Leone. The epidemic model exhibits two equilibria, namely, the disease-free and unique endemic equilibria. Existence and local stability of these equilibria are explored. Using central manifold theory, it is established that the transcritical bifurcation occurs when basic reproduction number passes through unity. The proposed Ebola epidemic model provides an estimate to the potential number of future cases. The model indicates that the disease will decline after peaking if multisectorial and multinational efforts to control the spread of infection are maintained. Possible implication of the results for disease eradication and its control are discussed which suggests that proper control strategies like: (i) transmission precautions, (ii) isolation and care of infectious Ebola patients, (iii) safe burial, (iv) contact tracing with follow-up and quarantine, and (v) early diagnosis are needed to stop the recurrent outbreak.

  13. A chaotic model for the epidemic of Ebola virus disease in West Africa (2013-2016)

    NASA Astrophysics Data System (ADS)

    Mangiarotti, Sylvain; Peyre, Marisa; Huc, Mireille

    2016-11-01

    An epidemic of Ebola Virus Disease (EVD) broke out in Guinea in December 2013. It was only identified in March 2014 while it had already spread out in Liberia and Sierra Leone. The spill over of the disease became uncontrollable and the epidemic could not be stopped before 2016. The time evolution of this epidemic is revisited here with the global modeling technique which was designed to obtain the deterministic models from single time series. A generalized formulation of this technique for multivariate time series is introduced. It is applied to the epidemic of EVD in West Africa focusing on the period between March 2014 and January 2015, that is, before any detected signs of weakening. Data gathered by the World Health Organization, based on the official publications of the Ministries of Health of the three main countries involved in this epidemic, are considered in our analysis. Two observed time series are used: the daily numbers of infections and deaths. A four-dimensional model producing a very complex dynamical behavior is obtained. The model is tested in order to investigate its skills and drawbacks. Our global analysis clearly helps to distinguish three main stages during the epidemic. A characterization of the obtained attractor is also performed. In particular, the topology of the chaotic attractor is analyzed and a skeleton is obtained for its structure.

  14. Multisensor monitoring of deforestation in the Guinea Highlands of West Africa

    NASA Technical Reports Server (NTRS)

    Gilruth, Peter T.; Hutchinson, Charles F.

    1990-01-01

    Multiple remote sensing systems were used to assess deforestation in the Guinea Highlands (Fouta Djallon) of West Africa. Sensor systems included: (1) historical (1953) and current (1989) aerial mapping photography; (2) current large-scale, small format (35mm) aerial photography; (3) current aerial video imagery; and (4) historical (1973) and recent (1985) LANDSAT MSS. Photographic and video data were manually interpreted and incorporated in a vector-based geographic information system (GIS). LANDSAT data were digitally classified. General results showed an increase in permanent and shifting agriculture over the past 35 years. This finding is consistent with hypothesized strategies to increase agricultural production through a shortening of the fallow period in areas of shifting cultivation. However, results also show that the total area of both permanent and shifting agriculture had expanded at the expense of natural vegetation and an increase in erosion. Although sequential LANDSAT MSS cannot be used in this region to accurately map land over, the location, direction and magnitude of changes can be detected in relative terms. Historical and current aerial photography can be used to map agricultural land use changes with some accuracy. Video imagery is useful as ancillary data for mapping vegetation. The most prudent approach to mapping deforestation would incorporate a multistage approach based on these sensors.

  15. Poverty, health and satellite-derived vegetation indices: their inter-spatial relationship in West Africa

    PubMed Central

    Sedda, Luigi; Tatem, Andrew J.; Morley, David W.; Atkinson, Peter M.; Wardrop, Nicola A.; Pezzulo, Carla; Sorichetta, Alessandro; Kuleszo, Joanna; Rogers, David J.

    2015-01-01

    Background Previous analyses have shown the individual correlations between poverty, health and satellite-derived vegetation indices such as the normalized difference vegetation index (NDVI). However, generally these analyses did not explore the statistical interconnections between poverty, health outcomes and NDVI. Methods In this research aspatial methods (principal component analysis) and spatial models (variography, factorial kriging and cokriging) were applied to investigate the correlations and spatial relationships between intensity of poverty, health (expressed as child mortality and undernutrition), and NDVI for a large area of West Africa. Results This research showed that the intensity of poverty (and hence child mortality and nutrition) varies inversely with NDVI. From the spatial point-of-view, similarities in the spatial variation of intensity of poverty and NDVI were found. Conclusions These results highlight the utility of satellite-based metrics for poverty models including health and ecological components and, in general for large scale analysis, estimation and optimisation of multidimensional poverty metrics. However, it also stresses the need for further studies on the causes of the association between NDVI, health and poverty. Once these relationships are confirmed and better understood, the presence of this ecological component in poverty metrics has the potential to facilitate the analysis of the impacts of climate change on the rural populations afflicted by poverty and child mortality. PMID:25733559

  16. Climatic controls on West Nile virus and Sindbis virus transmission and outbreaks in South Africa.

    PubMed

    Uejio, Christopher K; Kemp, Alan; Comrie, Andrew C

    2012-02-01

    The processes influencing the magnitude of West Nile virus (WNV) transmission from 1 year to the next require thorough investigation. The intensity of WNV transmission is related to the dynamics and interactions between the pathogen, vector, vertebrate hosts, and environment. Climatic variability is one process that can influence interannual disease transmission. South Africa has a long WNV and Sindbis virus (SINV) record where consistent climate and disease relationships can be identified. We relate climate conditions to historic mosquito infection rates. Next, we detect similar associations with reported human outbreaks dating back to 1941. Both concurrent summer precipitation and the change in summer precipitation from the previous to the current summer were strongly associated with WNV and SINV transmission and recorded human outbreaks. Each 100 mm interannual summer precipitation change increased WNV infection rates by 0.39 WNV-positive Culex univittatus/1000 tested Cx. univittatus. An improved understanding of biotic and abiotic disease transmission dynamics may help anticipate and mitigate future outbreaks.

  17. Intraseasonal variability of low-level moisture transport over West Africa

    NASA Astrophysics Data System (ADS)

    Lélé, M. Issa; Leslie, Lance M.

    2016-12-01

    The vertically integrated surface-850 hPa atmospheric water vapor flux is investigated, to account for the total low-level moisture flux contribution to rainfall over West Africa (WA), based on NCEP-NCAR reanalysis data. The focus is the contributions to total moisture transport and convergence by the mean circulation, the synoptic (<10 days), and climate (>10 day) scale anomalies. For WA, the time-mean flow and climate anomalies are comparable. Similarly, for meridional and zonal components, transports by the time-mean and climate anomalies are the largest contributors to mean meridional and zonal moisture transport. While the climate anomalies are responsible for driving moisture poleward from the Atlantic Ocean to the Guinea coast, and westward from the western Atlantic Ocean into the Sahel, the synoptic anomalies contribute to transporting moisture zonally out of the Sahel. Moreover, the spatial distribution of moisture flux convergence reveals a close similarity to the observed 2005 relatively wet and 2006 relatively dry accumulative rainfall. Convergence in WA is mainly the result of moisture transport by the mean flow. An enhanced (weak) flux convergence by the mean flow is characteristic of wet (dry) Sahel rainfall seasons. During wet April-June rainy seasons in the Guinea coast, enhanced convergence due to synoptic anomalies is observed in the region, whereas it is suppressed during dry April-June seasons. In the Sahel, however, during the dry rainy seasons, the convergence region due to synoptic anomalies is displaced southward.

  18. Mobile pastoralists in Central and West Africa: between conflict, mobile telephony and (im)mobility.

    PubMed

    De Bruijn, M; Amadou, A; Lewa Doksala, E; Sangaré, B

    2016-11-01

    The livelihoods of the Fulani mobile pastoralists in the Sahel, West and Central Africa are characterised by mobility (related to the needs of their animals), extensive social networks, and a focus on social ties as the basis of status and influence ('wealth in people'). The Sahel environment in which many Fulani nomads live has become embroiled in jihadism, conflict, and violence; at the same time, this region has experienced an increase in opportunities to connect through the wireless mobile communication system. This paper analyses the triangle of mobility, communication, and insecurity in order to understand the present-day situation of the nomadic and semi-nomadic Fulani pastoralists and their identity dynamics. The Fulani find themselves caught in between these conflicts, which end their mobility and often lead to the loss of their herds. Will they be able to keep their mobile lifestyle and identity? This article is based on qualitative case studies and the biographical narratives of nomadic and semi-nomadic pastoralists who have lived through conflict and violence in Cameroon, Chad and Mali. These case studies show that, despite the fact that mobile pastoralism has become difficult as a consequence of the conflicts and loss of cattle, the 'mobile' identity is very present and reinforced with the help of mobile telephony, through which social networks and 'wealth in people' are sustained.

  19. Distinguishing epidemiological features of the 2013–2016 West Africa Ebola virus disease outbreak

    PubMed Central

    Shultz, James M.; Espinel, Zelde; Espinola, Maria; Rechkemmer, Andreas

    2016-01-01

    ABSTRACT The 2013–2016 West Africa Ebola virus disease epidemic was notable for its scope, scale, and complexity. This briefing presents a series of distinguishing epidemiological features that set this outbreak apart. Compared to one concurrent and 23 previous outbreaks of the disease over 40 years, this was the only occurrence of Ebola virus disease involving multiple nations and qualifying as a pandemic. Across multiple measures of magnitude, the 2013–2016 outbreak was accurately described using superlatives: largest and deadliest in terms of numbers of cases and fatalities; longest in duration; and most widely dispersed geographically, with outbreak-associated cases occurring in 10 nations. In contrast, the case-fatality rate was much lower for the 2013–2016 outbreak compared to the other 24 outbreaks. A population of particular interest for ongoing monitoring and public health surveillance is comprised of more than 17,000 “survivors,” Ebola patients who successfully recovered from their illness. The daunting challenges posed by this outbreak were met by an intensive international public health response. The near-exponential rate of increase of incident Ebola cases during mid-2014 was successfully slowed, reversed, and finally halted through the application of multiple disease containment and intervention strategies. PMID:28229017

  20. Mining and environmental change in Sierra Leone, West Africa: a remote sensing and hydrogeomorphological study.

    PubMed

    Akiwumi, Fenda A; Butler, David R

    2008-07-01

    This paper evaluates the environmental changes in southwestern Sierra Leone, West Africa from rutile (titanium dioxide) between 1967 and 1995. Mining in peripheral parts of the world economy is a consequence of larger global economic interests. Historically, long-distance trade and export production of minerals and other natural resources primarily for the benefit of core countries are responsible for transforming the natural environment and landscapes of peripheral sectors of the world economy. Tracking environmental change in developing countries such as Sierra Leone is challenging because of financial and infrastructural constraints on the use of ground methods of evaluation and monitoring. Remote sensing data are invaluable in assessing the human dimensions of Land Use and Land Cover Change (LULCC) with implications for political ecology. Using available multi-date infrared Landsat images supplemented with field hydrological and biophysical data, we monitored the rapid temporal and spatial dynamic characteristic of mining areas in the study area with a focus on physical changes to the landscape. Reservoir construction for mining has caused flooding of alluvial lowlands, deforestation, and the creation of tailings and stockpiles over mined-out portions of the lease. Although the study was conducted at a local scale, it represents the broad, regional, past-to-present manner by which global economic interests exploit natural resources and impact the environment in distant places.

  1. Bilharziasis survey in British West and East Africa, Nyasaland, and the Rhodesias*

    PubMed Central

    Blair, Dyson M.

    1956-01-01

    The author, in his capacity as a WHO consultant, undertook a survey of bilharziasis in British West and East Africa and Nyasaland during 1950-51. The information thus obtained has been revised and brought up to date and is recorded in the present article together with similar observations on Northern Rhodesia, which was not visited, and on Southern Rhodesia, the author's own country. In Part I, each country is dealt with in turn. The history of the disease and the findings of field surveys are reviewed, and, wherever possible, personal observations have been included. The fact that the information is of a scanty and incomplete nature is an indication that further local studies in all areas are badly needed. In Part II an attempt is made to survey the situation from the point of view of the various aspects of the subjects—methods of obtaining morbidity data, intensity of infection, effects of the disease on human health, treatment, and the molluscan vectors. PMID:13383363

  2. Water and carbon fluxes from savanna ecosystems of the Volta River watershed, West Africa

    NASA Astrophysics Data System (ADS)

    Freitag, Heiko; Ferguson, Paul R.; Dubois, Kristal; Hayford, Ebenezer Kofi; von Vordzogbe, Vincent; Veizer, Ján

    2008-03-01

    The fluxes of water and carbon from terrestrial ecosystems are coupled via the process of photosynthesis. Constraining the annual water cycle therefore allows first order estimates of annual photosynthetic carbon flux, providing that the components of evapotranspiration can be separated. In this study, an isotope mass-balance equation is utilized to constrain annual evaporation flux, which in turn, is used to determine the amount of water transferred to the atmosphere by plant transpiration. The Volta River watershed in West Africa is dominated by woodland and savanna ecosystems with a significant proportion of C 4 vegetation. Annually, the Volta watershed receives ˜ 380 km 3 of rainfall, ˜ 50% of which is returned to the atmosphere via transpiration. An annual photosynthetic carbon flux of ˜ 170 × 10 12 g C yr - 1 or ˜ 428 g C m - 2 was estimated to be associated with this water vapor flux. Independent estimates of heterotrophic soil respiration slightly exceeded the NPP estimate from this study, implying that the exchange of carbon between the Volta River watershed and the atmosphere was close to being in balance or that terrestrial ecosystems were a small annual source of CO 2 to the atmosphere. In addition to terrestrial carbon flux, the balance of photosynthesis and respiration in Volta Lake was also examined. The lake was found to evade carbon dioxide to the atmosphere although the magnitude of the flux was much smaller than that of the terrestrial ecosystems.

  3. Assessing the performance of dynamical and statistical downscaling techniques to simulate crop yield in West Africa

    NASA Astrophysics Data System (ADS)

    Sultan, B.; Oettli, P.; Vrac, M.; Baron, C.

    2010-12-01

    Global circulation models (GCM) are increasingly capable of making relevant predictions of seasonal and long-term climate variability, thus improving prospects of predicting impact on crop yields. This is particularly important for semi-arid West Africa where climate variability and drought threaten food security. Translating GCM outputs into attainable crop yields is difficult because GCM grid boxes are of larger scale than the processes governing yield, involving partitioning of rain among runoff, evaporation, transpiration, drainage and storage at plot scale. It therefore requires the use of downscaling methods. This study analyzes the performance of both dynamical and statistical downscaling techniques in simulating crop yield at local scale. A detailed case study is conducted using historical weather data for Senegal, applied to the crop model SARRAH for simulating several tropical cereals (sorghum, millet, maize) at local scale. This control simulation is used as a benchmark to evaluate a set of Regional Climate Models (RCM) simulations, forced by ERA-Interim, from the ENSEMBLES project and a statistical downscaling method, the CDF-Transform, used to correct biases in RCM outputs. We first evaluate each climate variable that drives the simulated yield in the control simulation (radiation, rainfall, temperatures). We then simulate crop yields with RCM outputs (with or without applying the CDG-Transform) and evaluate the performance of each RCM in regards to crop yield simulations.

  4. Farmer-managed natural regeneration enhances rural livelihoods in dryland west Africa.

    PubMed

    Weston, Peter; Hong, Reaksmey; Kaboré, Carolyn; Kull, Christian A

    2015-06-01

    Declining agricultural productivity, land clearance and climate change are compounding the vulnerability of already marginal rural populations in West Africa. 'Farmer-Managed Natural Regeneration' (FMNR) is an approach to arable land restoration and reforestation that seeks to reconcile sustained food production, conservation of soils, and protection of biodiversity. It involves selecting and protecting the most vigorous stems regrowing from live stumps of felled trees, pruning off all other stems, and pollarding the chosen stems to grow into straight trunks. Despite widespread enthusiasm and application of FMNR by environmental management and development projects, to date, no research has provided a measure of the aggregate livelihood impact of community adoption of FMNR. This paper places FMNR in the context of other agroforestry initiatives, then seeks to quantify the value of livelihood outcomes of FMNR. We review published and unpublished evidence about the impacts of FMNR, and present a new case study that addresses gaps in the evidence-base. The case study focuses on a FMNR project in the district of Talensi in the semi-arid Upper East Region in Ghana. The case study employs a social return on investment analysis, which identifies proxy financial values for non-economic as well as economic benefits. The results demonstrate income and agricultural benefits, but also show that asset creation, increased consumption of wild resources, health improvements, and psycho-social benefits created more value in FMNR-adopting households during the period of the study than increases in income and agricultural yields.

  5. Reproductive characteristics of Mastomys natalensis and Lassa virus prevalence in Guinea, West Africa.

    PubMed

    Fichet-Calvet, Elisabeth; Lecompte, Emilie; Koivogui, Lamine; Daffis, Stéphane; ter Meulen, Jan

    2008-01-01

    We recently reported increased prevalence of Lassa virus (LASV) infection in Mastomys natalensis during the rainy season in Guinea, West Africa. Here, the association of LASV prevalence with fecundity, fertility, and the age structure of the rodent population was analyzed using data from the previous study. The animals reproduced throughout the year, but highest fecundity was observed during the rainy season. Accordingly, the rodent population was aged at the beginning and young at the end of the rainy season. Lassa virus infection was observed in all age groups, including the very young, which is compatible with vertical transmission. However, since the prevalence of infection showed a trend with increasing age in the younger age groups, horizontal transmission by yet unknown mechanisms may also play a role in LASV transmission. Multivariate analysis did not show an association of LASV prevalence with any demographic variable studied. Rodent behavior influencing virus transmissibility and contaminated environment may therefore be responsible for spatial and seasonal variations in LASV prevalence in M. natalensis.

  6. Regional-scale climate-variability synchrony of cholera epidemics in West Africa

    PubMed Central

    Constantin de Magny, Guillaume; Guégan, Jean-François; Petit, Michel; Cazelles, Bernard

    2007-01-01

    Background The relationship between cholera and climate was explored in Africa, the continent with the most reported cases, by analyzing monthly 20-year cholera time series for five coastal adjoining West African countries: Côte d'Ivoire, Ghana, Togo, Benin and Nigeria. Methods We used wavelet analyses and derived methods because these are useful mathematical tools to provide information on the evolution of the periodic component over time and allow quantification of non-stationary associations between time series. Results The temporal variability of cholera incidence exhibits an interannual component, and a significant synchrony in cholera epidemics is highlighted at the end of the 1980's. This observed synchrony across countries, even if transient through time, is also coherent with both the local variability of rainfall and the global climate variability quantified by the Indian Oscillation Index. Conclusion Results of this study suggest that large and regional scale climate variability influence both the temporal dynamics and the spatial synchrony of cholera epidemics in human populations in the Gulf of Guinea, as has been described for two other tropical regions of the world, western South America and Bangladesh. PMID:17371602

  7. Toward a Socio-Territorial Approach to Health: Health Equity in West Africa.

    PubMed

    Vialard, Lucie; Squiban, Clara; Fournet, Florence; Salem, Gérard; Foley, Ellen E

    2017-01-22

    This study contributes to the literature about the effects of space and place on health by introducing a socio-territorial approach to urban health disparities in West Africa. It explores how urban spaces, specifically neighbourhoods, are shaped by social and economic relations and strategies of territorial control. We examine the potential influence of socio-territorial processes on vulnerability to disease, access to medical care, healthscapes, and illness experiences. Our research was conducted in Senegal and relied on a mixed methods design. We identified four neighbourhoods that represent the socio-spatial heterogeneity of the city of Saint-Louis and utilized the following methods: geographic and anthropological field research, household surveys, health knowledge and behaviour surveys, clinical exams, and illness interviews. Our results highlight the socio-territorial processes at work in each neighbourhood, clinical findings on three health measures (overweight, high blood pressure, and hyperglycaemia) and health experiences of individuals with hypertension or type II diabetes. We found significant differences in the prevalence of the three health measures in the study sites, while experiences managing hypertension and diabetes were similar. We conclude that a socio-territorial approach offers insight into the complex constellation of forces that produce health disparities in urban settings.

  8. A chaotic model for the epidemic of Ebola virus disease in West Africa (2013-2016).

    PubMed

    Mangiarotti, Sylvain; Peyre, Marisa; Huc, Mireille

    2016-11-01

    An epidemic of Ebola Virus Disease (EVD) broke out in Guinea in December 2013. It was only identified in March 2014 while it had already spread out in Liberia and Sierra Leone. The spill over of the disease became uncontrollable and the epidemic could not be stopped before 2016. The time evolution of this epidemic is revisited here with the global modeling technique which was designed to obtain the deterministic models from single time series. A generalized formulation of this technique for multivariate time series is introduced. It is applied to the epidemic of EVD in West Africa focusing on the period between March 2014 and January 2015, that is, before any detected signs of weakening. Data gathered by the World Health Organization, based on the official publications of the Ministries of Health of the three main countries involved in this epidemic, are considered in our analysis. Two observed time series are used: the daily numbers of infections and deaths. A four-dimensional model producing a very complex dynamical behavior is obtained. The model is tested in order to investigate its skills and drawbacks. Our global analysis clearly helps to distinguish three main stages during the epidemic. A characterization of the obtained attractor is also performed. In particular, the topology of the chaotic attractor is analyzed and a skeleton is obtained for its structure.

  9. Natural enemies of the maize cob borer, Mussidia nigrivenella (Lepidoptera: Pyralidae) in Benin, West Africa.

    PubMed

    Sétamou, M; Schulthess, F; Goergen, G; Poehling, H-M; Borgemeister, C

    2002-08-01

    Mussidia nigrivenella Ragonot is a pest of maize cobs in West Africa. It significantly reduces maize yields and grain quality, with quantitative losses of 2-25%at harvest, and up to 10-15% indirect losses due to an increase in storage pest infestation levels. Infestation by M. nigrivenella also significantly increased the susceptibility of maize to Aspergillus flavus infection and subsequent aflatoxin contamination. Surveys conducted in different agro-ecological zones of Benin on cultivated and wild host plants during 1994-1997 revealed one egg parasitoid, three larval parasitoids and one pupal parasitoid attacking M. nigrivenella. Egg parasitism was scarce on all host plants sampled and in all four agro-ecological zones. Parasitism by larval and pupal parasitoids was usually less than 10%, and varied with host plant species. Both larval and pupal parasitoids were rare or absent in cultivated maize fields. The solitary chalcidid pupal parasitoid, Antrocephalus crassipes Masi, was the predominant species, contributing approximately 53% of the observed mortality. Logistic regression analysis indicated that this parasitoid was more prevalent on fruits of Gardenia spp. (Rubiaceae) than on the other host plant species including maize used by M. nigrivenella, and was most abundant between February and September. The differences in parasitoid diversity and parasitism between Benin and other regions suggest that there are opportunities for biological control through introduction of exotic parasitoids or using the 'new association' approach, which uses natural enemies of closely related host species that occupy similar ecological niches to the target pest.

  10. On the tectonics and metallogenesis of West Africa: a model incorporating new geophysical data

    USGS Publications Warehouse

    Hastings, David A.

    1982-01-01

    The gold, diamond and manganese deposits of Ghana have attracted commercial interest, but appropriate geophysical data to delineate the tectonic setting of these and other deposits have been lacking until recently. Recent gravity surveys, however, now cover about 75% of the country. When used in a synthesis of the sometimes contradictory existing theories about the geology and metallogenesis of West Africa, the available gravity, magnetic, and seismic data lead to a preliminary tectonic model that postulates rifting at the time of the (1800-2000 m.y. old) Eburnean orogeny and is consistent with the occurrences of mineral deposits in the region. In this model, diamond-bearing kimberlites formed during the commencement of rifting during the Eburnean orogenesis. Later emplacement of kimberlites was associated with the initiation of Mesozoic rifting of Gondwanaland. Primary gold vein deposits were probably formed by the migration of hydrothermal fluids (associated with the formation of granitoids) into dilatant zones, such as rift-related faults and anticlinal axial areas, toward the end of the Eburnean orogeny. At this time, the major concordant granitoids were formed, with smaller plutonic granitoids forming on the fringes of the concordant masses as partial melting fractions of the latter. Sedimentary manganese deposits were formed along the margins of rift lakes toward the end of the orogeny.

  11. Suitability Evaluation for Lowland Rice in Inland Valleys in West Africa

    NASA Astrophysics Data System (ADS)

    Hideto, Fujii; Muralikrishna, Gumma; Prasad, Thenkabail; Regassa, Namara

    A GIS based model developed by the authors are applied for selecting suitable rice cultivation area in inland valleys that has high potential for rice production in West Africa where rice consumption is increasing very rapidly. The model has the following features. 1) The model is to evaluate the suitability of the land for lowland rice based on score distribution maps respectively made by the data of 29 evaluation parameters. 2) The parameters are classified into 4 categories; bio-physical, technical, socio-economic and health-environmental parameters. 3) Each scored map (layer) is integrated to obtain total scores by multiplying a weight which is determined by the importance of parameters. The suitability for rice in two study sites was evaluated using the model. Mankran and Jolo-Kwaha watershed selected as the study sites from different agro-ecological zone in Ghana. Applying the data of 12 parameters acquired in the study sites to the model, “very suitable” or “suitable” occupies around 30% in Mankran study site and around 60% in Jolo-Kwaha study site.

  12. Oxygen, hydrogen, and helium isotopes for investigating groundwater systems of the Cape Verde Islands, West Africa

    USGS Publications Warehouse

    Heilweil, V.M.; Solomon, K.D.; Gingerich, S.B.; Verstraeten, Ingrid M.

    2009-01-01

    Stable isotopes (??18O, ??2H), tritium (3H), and helium isotopes (3He, 4He) were used for evaluating groundwater recharge sources, flow paths, and residence times of three watersheds in the Cape Verde Islands (West Africa). Stable isotopes indicate the predominance of high-elevation precipitation that undergoes little evaporation prior to groundwater recharge. In contrast to other active oceanic hotspots, environmental tracers show that deep geothermal circulation does not strongly affect groundwater. Low tritium concentrations at seven groundwater sites indicate groundwater residence times of more than 50 years. Higher tritium values at other sites suggest some recent recharge. High 4He and 3He/4He ratios precluded 3H/3He dating at six sites. These high 3He/4He ratios (R/Ra values of up to 8.3) are consistent with reported mantle derived helium of oceanic island basalts in Cape Verde and provided end-member constraints for improved dating at seven other locations. Tritium and 3H/3He dating shows that S??o Nicolau Island's Ribeira Faj?? Basin has groundwater residence times of more than 50 years, whereas Fogo Island's Mosteiros Basin and Santo Ant??o Island's Ribeira Paul Basin contain a mixture of young and old groundwater. Young ages at selected sites within these two basins indicate local recharge and potential groundwater susceptibility to surface contamination and/or salt-water intrusion. ?? Springer-Verlag 2009.

  13. An evaluability assessment of a West Africa based Non-Governmental Organization's (NGO) progressive evaluation strategy.

    PubMed

    D'Ostie-Racine, Léna; Dagenais, Christian; Ridde, Valéry

    2013-02-01

    While program evaluations are increasingly valued by international organizations to inform practices and public policies, actual evaluation use (EU) in such contexts is inconsistent. Moreover, empirical literature on EU in the context of humanitarian Non-Governmental Organizations (NGOs) is very limited. The current article focuses on the evaluability assessment (EA) of a West-Africa based humanitarian NGO's progressive evaluation strategy. Since 2007, the NGO has established an evaluation strategy to inform its maternal and child health care user-fee exemption intervention. Using Wholey's (2004) framework, the current EA enabled us to clarify with the NGO's evaluation partners the intent of their evaluation strategy and to design its program logic model. The EA ascertained the plausibility of the evaluation strategy's objectives, the accessibility of relevant data, and the utility for intended users of evaluating both the evaluation strategy and the conditions that foster EU. Hence, key evaluability conditions for an EU study were assured. This article provides an example of EA procedures when such guidance is scant in the literature. It also offers an opportunity to analyze critically the use of EAs in the context of a humanitarian NGO's collaboration with evaluators and political actors.

  14. Farmer-Managed Natural Regeneration Enhances Rural Livelihoods in Dryland West Africa

    NASA Astrophysics Data System (ADS)

    Weston, Peter; Hong, Reaksmey; Kaboré, Carolyn; Kull, Christian A.

    2015-06-01

    Declining agricultural productivity, land clearance and climate change are compounding the vulnerability of already marginal rural populations in West Africa. `Farmer-Managed Natural Regeneration' (FMNR) is an approach to arable land restoration and reforestation that seeks to reconcile sustained food production, conservation of soils, and protection of biodiversity. It involves selecting and protecting the most vigorous stems regrowing from live stumps of felled trees, pruning off all other stems, and pollarding the chosen stems to grow into straight trunks. Despite widespread enthusiasm and application of FMNR by environmental management and development projects, to date, no research has provided a measure of the aggregate livelihood impact of community adoption of FMNR. This paper places FMNR in the context of other agroforestry initiatives, then seeks to quantify the value of livelihood outcomes of FMNR. We review published and unpublished evidence about the impacts of FMNR, and present a new case study that addresses gaps in the evidence-base. The case study focuses on a FMNR project in the district of Talensi in the semi-arid Upper East Region in Ghana. The case study employs a social return on investment analysis, which identifies proxy financial values for non-economic as well as economic benefits. The results demonstrate income and agricultural benefits, but also show that asset creation, increased consumption of wild resources, health improvements, and psycho-social benefits created more value in FMNR-adopting households during the period of the study than increases in income and agricultural yields.

  15. Africa: Prosperous times

    SciTech Connect

    1996-08-01

    Political instability and corruption is the rule, rather than the exception, in Africa`s main producing regions, but exploration and production prospects there are bright and attractive to foreign operators. The paper discusses exploration, drilling, resource development, and production in Nigeria, Libya, Algeria, Egypt, Angola, Congo, Gabon, and Tunisia. The other countries of Africa are briefly mentioned, i.e., Cameroon, Cote D`Ivoire, South Africa, Sudan, Namibia, Equatorial Guinea, Eritrea, Zaire, Mozambique, Ghana, Niger, and Seychelles.

  16. Dust aerosol radiative effect and forcing over West Africa : A case study from the AMMA SOP

    NASA Astrophysics Data System (ADS)

    Lemaître, C.; Flamant, C.; Pelon, J.; Cuesta, J.; Chazette, P.; Raut, J. C.

    2009-04-01

    The massive transport of arid dust by the African easterly jet (AEJ) can impact the dynamic of the AEJ and modify the development of westerly African waves through modifications of horizontal temperature gradient. Hence, it is important to evaluate the radiative impact of dust and their effect on thermodynamical properties of the AEJ. In this presentation, the impact of aerosol on solar and infra-red fluxes and the heating rate due to dust over West Africa are investigated using the radiative code STREAMER, as well as space-borne and airborne lidars (CALIPSO and LEANDRE 2, respectively) as well as dropsonde observations acquired during the African Monsoon Multidisciplinary Analysis Special Observing Period. Aircraft operations were conducted on 13 and 14 June 2006, over Benin and Niger. On these days the dust observed over Benin and Niger originated from the Bodélé depression and from West Sudan. In this study, we use aerosol extinction coefficient derived from lidar, as well as temperature, pressure and water vapour profiles derived from dropsondes as inputs to STREAMER. The surface albedo is obtained with MODIS. A series of runs was carried out on 13 and 14 June 2006, around mid-day, to investigate the dust radiative forcing as a function of latitude, from 6°N to 15°N, i.e. between the vegetated coast of the Guinea Gulf and the arid Sahel. In the solar spectrum, the maximum heating rate associated with the dust plume on these days was comprised between 1.5 K/day and 3 K/day, depending on the aerosol load, over the entire Sudanian and Sahel regions as inferred from CALIPSO. Sensitivity studies to surface albedo, aerosol backscatter-to-extinction ratio, temperature and water vapor mixing ratio profiles were also conducted.

  17. Estimating some parameters of the equatorial ionosphere electrodynamics from ionosonde data in West Africa

    NASA Astrophysics Data System (ADS)

    Grodji, F. O.; Doumbia, V.; Boka, K.; Amory-Mazaudier, C.; Cohen, Y.; Fleury, R.

    2017-01-01

    During the International Equatorial Electrojet Year (IEEY), an IPS-42 ionosonde located at Korhogo (9.33°N, 5.42°W, -1.88° dip-lat) and a meridian chain of 10 magnetic stations were setup in West Africa (5°West longitude). In this work, some characteristic parameters of the equatorial electrojet were estimated on the basis of the IPS-42 ionosonde data at Korhogo during the years 1993 and 1994. The study consisted of determining the zonal electric field through an estimate of the plasma vertical drift velocity. The daytime plasma vertical drift velocity was estimated from the time rates of change of the F-layer virtual height variations and a correction term that takes into account the ionization production and recombination effects. This method resulted in an improved vertical drift velocity, which was found to be comparable to the results of previous studies. The estimated vertical drift velocity was used in a semi-empirical approach which involved the IRI-2012 model for the Pedersen and Hall conductivities and the IGRF-10 model for the geomagnetic main field intensity. Thus the zonal and polarization electric fields on one hand, and the eastward Pedersen, Hall and the equatorial electrojet current densities on the other hand, were estimated. Furthermore the integrated peak current density at the EEJ center was estimated from ionosonde observations and compared with that inferred from magnetometer data. The integrated EEJ peak current densities obtained from both experiments were found to be in the same order and their seasonal variations exhibit the same trends as well.

  18. Impact of land cover characterization on regional climate modeling over West Africa

    NASA Astrophysics Data System (ADS)

    Sylla, Mouhamadou Bamba; Pal, Jeremy S.; Wang, Guiling L.; Lawrence, Peter J.

    2016-01-01

    The impact of high resolution modern vegetation cover on the West African climate is examined using the International Centre for Theoretical Physics Regional Climate Model implementing the NCAR Community Land Model. Two high resolution 25 km long-term simulations driven by the output from a coarser 50-km resolution simulation are performed for the period 1998-2010. One high resolution simulation uses an earlier and coarser-resolution version of plant functional type distribution and leaf area index, while the other uses a more recent, higher-quality, and finer-resolution version of the data. The results indicate that the new land cover distribution substantially alters the distribution of temperature with warming in Central Nigeria, northern Gulf of Guinea and part of the Sahel due to the replacement of C4 grass with corn; and cooling along the coastlines of the Gulf of Guinea and in Central Africa due to the replacement of C4 grass with tropical broadleaf evergreen trees. Changes in latent heat flux appear to be largely responsible for these temperature changes with a net decrease (increase) in regions of warming (cooling). The improved land cover distribution also results in a wetter monsoon season. The presence of corn tends to favor larger precipitation amounts via more intense events, while the presence of tropical broadleaf evergreen trees tends to favor the occurrence of both more intense and more frequent events. The wetter conditions appear to be sustained via (1) an enhanced soil moisture feedback; and (2) elevated moisture transport due to increased low-level convergence in regions south of 10N where the most substantial land cover differences are present. Overall the changes induced by the improved vegetation cover improve, to some extent, the performance of the high resolution regional climate model in simulating the main West African summer monsoon features.

  19. Legume Diversity Patterns in West Central Africa: Influence of Species Biology on Distribution Models

    PubMed Central

    de la Estrella, Manuel; Mateo, Rubén G.; Wieringa, Jan J.; Mackinder, Barbara; Muñoz, Jesús

    2012-01-01

    Objectives Species Distribution Models (SDMs) are used to produce predictions of potential Leguminosae diversity in West Central Africa. Those predictions are evaluated subsequently using expert opinion. The established methodology of combining all SDMs is refined to assess species diversity within five defined vegetation types. Potential species diversity is thus predicted for each vegetation type respectively. The primary aim of the new methodology is to define, in more detail, areas of species richness for conservation planning. Methodology Using Maxent, SDMs based on a suite of 14 environmental predictors were generated for 185 West Central African Leguminosae species, each categorised according to one of five vegetation types: Afromontane, coastal, non-flooded forest, open formations, or riverine forest. The relative contribution of each environmental variable was compared between different vegetation types using a nonparametric Kruskal-Wallis analysis followed by a post-hoc Kruskal-Wallis Paired Comparison contrast. Legume species diversity patterns were explored initially using the typical method of stacking all SDMs. Subsequently, five different ensemble models were generated by partitioning SDMs according to vegetation category. Ecological modelers worked with legume specialists to improve data integrity and integrate expert opinion in the interpretation of individual species models and potential species richness predictions for different vegetation types. Results/Conclusions Of the 14 environmental predictors used, five showed no difference in their relative contribution to the different vegetation models. Of the nine discriminating variables, the majority were related to temperature variation. The set of variables that played a major role in the Afromontane species diversity model differed significantly from the sets of variables of greatest relative important in other vegetation categories. The traditional approach of stacking all SDMs indicated overall

  20. The Latitudinal Gradient of Rainfall, Mineralogy, Albedo and Magnetic Susceptibility in West Africa

    NASA Astrophysics Data System (ADS)

    Williams, E. R.; Balsam, W.; Schaaf, C.; Yang, X.; Zhang, Q.; Ji, J.; Rossman, G.; Garimella, S.; Oldfield, F.; Lyons, J. R.; Ellwood, B.; Hartman, H.; Hicks, E.; Mansot, J. L.; Cesaire, T.; Thomas, P.

    2008-12-01

    In order to investigate the effect of climate on soil and surface sediment properties we examined four transects around the Sahara Desert. The transects were located in Mali, Niger, Benin, Togo, Egypt and Morocco and, with the exception of Egypt, each crossed a significant climatological rainfall gradient. The Egyptian transect was designed to characterize one of the driest portions of the Sahara Desert. Our study included laboratory measurements of mineralogy (XRD), elemental composition (XRF), grain size, optical reflectance (lab), magnetic susceptibility (MS)and remanences. In addition, albedo was determined from the MODIS satellite imagery from space. Many of our laboratory measurements exhibited variations with the rainfall gradient. Iron oxides (hematite and goethite), kaolinite, Al2O3, and TiO2 increased with increasing rainfall whereas SiO2, illite, and grain size decreased with increasing rainfall. Both laboratory-determined reflectivity and satellite-determine albedo decreased as rainfall increased. In part, this decrease in reflectivity/albedo with increasing rainfall appears to be the result of hematite, the dominant coloring agent for the soil in this region and the origin of the 'red' Sahel. The physical interpretation of these results centers on rainfall as a long-term leaching agent of surface material, and the control of physical properties by specific mineralogy. SiO2 is highly reflective and iron oxides are strongly absorptive in the visible range. The solubility of SiO2 in rainwater is orders of magnitude larger than all the iron oxides, with hematite the least soluble. It has long been recognized that leaching by rainfall produces dark red laterite in the near-surface oxidizing environment, a prominent geological feature throughout the high rainfall belt of West Africa. Laterite beds represent simultaneous enrichments of all iron oxides and a reduction in SiO2 by leaching. In the Sahara desert where rainfall is minimal (<10 mm/yr), SiO2 is

  1. University-level nutrition training in West Africa: cost and financing issues

    PubMed Central

    Sodjinou, Roger; Bosu, William; Fanou, Nadia; Zagre, Noel; Tchibindat, Félicité; Baker, Shawn; Delisle, Helene

    2015-01-01

    Background There is a serious shortage of skilled nutrition professionals in West Africa. Investing in nutrition training is one of the strategies for strengthening the human resource base in nutrition. However, little is known about how nutrition training in the region is financed and the levels of tuition fees charged. The purpose of this study was to provide a comprehensive assessment about the levels of tuition fees charged for nutrition training in the West Africa region and to determine to what extent this is of reach to the average student. Methodology The data for this study were obtained from 74 nutrition degree programs operating in nine West African countries in 2013 through semi-structured interviews during on-site visits or through self-administered questionnaires. They included the age of the programs, school ownership, tuition fees, financial assistance, and main sources of funding. Tuition fees (in 2013 US$) were expressed per program to enable uniformity and comparability. Simple descriptive and bivariate analyses were performed. Results Results from 74 nutrition training programs in nine countries showed a wide variation in tuition fees within and between countries. The tuition fees for bachelor's, master's, and doctoral programs, respectively, ranged from 372 to 4,325 (mean: 2,353); 162 to 7,678 (mean: 2,232); and 369 to 5,600 (mean: 2,208). The tuition fees were significantly higher (p<0.05) in private institutions than in public institutions (mean: US$3,079 vs. US$2,029 for bachelor's programs; US$5,118 vs. US$1,820 for master's programs; and US$3,076 vs. US$1,815 for doctoral programs). The difference in the tuition fees between Francophone and Anglophone countries was not statistically significant (mean: US$2,570 vs. US$2,216 for bachelor's programs; US$2,417 vs. US$2,147 for master's programs; US$3,285 vs. US$2,055 for doctoral programs). In most countries, the tuition fees appeared to be out of reach of the average student. Recent master

  2. Effectiveness of Alternative Extension Methods through Radio Broadcasting in West Africa

    ERIC Educational Resources Information Center

    Moussa, Bokar; Otoo, Miriam; Fulton, Joan; Lowenberg-DeBoer, James

    2011-01-01

    There is an urgent need to quantify which extension methods are most effective in Africa. The objective of this study was to determine the impact of alternative extension methods on adoption of the triple bagging cowpea storage technology in Niger and Burkina Faso. This study was designed as a quasi-experiment with two alternative extension…

  3. Ebola virus disease: a highly fatal infectious disease reemerging in West Africa.

    PubMed

    To, Kelvin K W; Chan, Jasper F W; Tsang, Alan K L; Cheng, Vincent C C; Yuen, Kwok-Yung

    2015-02-01

    Ebolavirus can cause a highly fatal and panic-generating human disease which may jump from bats to other mammals and human. High viral loads in body fluids allow efficient transmission by contact. Lack of effective antivirals, vaccines and public health infrastructures in parts of Africa make it difficult to health workers to contain the outbreak.

  4. Gender Discrimination and Education in West Africa: Strategies for Maintaining Girls in School

    ERIC Educational Resources Information Center

    Tuwor, Theresa; Sossou, Marie-Antoinette

    2008-01-01

    Girls' enrolment in primary schools has achieved significant increase and parity with male enrolment in many countries in Africa since the 1960s. Some of these countries include Botswana, Namibia and Tanzania. However, in most Sub-Saharan African countries, female enrolment still lags behind male enrolment. This paper examines some of the reasons…

  5. Stabilization of large drainage basins over geological time scales: Cenozoic West Africa, hot spot swell growth, and the Niger River

    NASA Astrophysics Data System (ADS)

    Chardon, Dominique; Grimaud, Jean-Louis; Rouby, Delphine; Beauvais, Anicet; Christophoul, Frédéric

    2016-03-01

    Reconstructing the evolving geometry of large river catchments over geological time scales is crucial to constraining yields to sedimentary basins. In the case of Africa, it should further help deciphering the response of large cratonic sediment routing systems to Cenozoic growth of the basin-and-swell topography of the continent. Mapping of dated and regionally correlated lateritic paleolandscape remnants complemented by onshore sedimentological archives allows the reconstruction of two physiographic configurations of West Africa in the Paleogene. Those reconstructions show that the geometry of the drainage is stabilized by the late early Oligocene (29 Ma) and probably by the end of the Eocene (34 Ma), allowing to effectively link the inland morphoclimatic record to offshore sedimentation since that time, particularly in the case of the Niger catchment—delta system. Mid-Eocene paleogeography reveals the antiquity of the Senegambia catchment back to at least 45 Ma and suggests that a marginal upwarp forming a continental divide preexisted early Oligocene connection of the Niger and Volta catchments to the Equatorial Atlantic Ocean. Such a drainage rearrangement was primarily enhanced by the topographic growth of the Hoggar hot spot swell and caused a stratigraphic turnover along the Equatorial margin of West Africa.

  6. Control of Saharan mineral dust transport to Barbados in winter by the Intertropical Convergence Zone over West Africa

    NASA Astrophysics Data System (ADS)

    Doherty, O. M.; Riemer, N.; Hameed, S.

    2012-10-01

    The reasons for the inter-annual variability of dust transport from the Sahara across the Atlantic are not well-understood. Here we address this issue by defining three new climate indices that capture the position and intensity of the zone of near-surface convergence over West Africa, a part of the global Intertropical Convergence Zone (ITCZ). We then relate these indices to a 38-year record of mineral dust concentrations at Barbados focusing on the winter season. The results show that the latitudinal displacement of the ITCZ over West Africa and the dust load in Barbados are statistically significantly correlated with a correlation coefficient ofr= -0.69. A southward movement of the ITCZ corresponds to an increased dust load at Barbados. This correlation represents an improvement upon previous results, which focused on traditional teleconnection indices such as the North Atlantic Oscillation or the El-Niño-Southern Oscillation. From analyzing composites of wind and precipitation we conclude that for the winter season, the inter-annual variability of the Barbados dust load is related to changes in near-surface northeasterly winds in semi-arid regions in North Africa coincident with the movement of the ITCZ. Changes in precipitation appear to only play a minor role.

  7. Precipitation recycling in West Africa - regional modeling, evaporation tagging and atmospheric water budget analysis

    NASA Astrophysics Data System (ADS)

    Arnault, Joel; Kunstmann, Harald; Knoche, Hans-Richard

    2015-04-01

    -atmospheric processes involved in the atmospheric branch of the water cycle in West Africa, based on our WRF simulation. We will particularly focus on the respective contribution of local and remote water vapor to atmospheric processes involved in local precipitation, and compare the results at the 100 and 1000 km2 scales. The potential impact of local land use change on local precipitation will finally be discussed based on this quantitative analysis.

  8. From institutionalization of user fees to their abolition in West Africa: a story of pilot projects and public policies

    PubMed Central

    2015-01-01

    This article analyzes the historical background of the institutionalization of user fees and their subsequent abolition in West Africa. Based on a narrative review, we present the context that frames the different articles in this supplement. We first show that a general consensus has emerged internationally against user fees, which were imposed widely in Africa in the 1980s and 1990s; at that time, the institutionalization of user fees was supported by evidence from pilot projects funded by international aid agencies. Since then there have been other pilot projects studying the abolition of user fees in the 2000s, but these have not yet had any real influence on public policies, which are often still chaotic. This perplexing situation might be explained more by ideologies and political will than by insufficient financial capacity of states. PMID:26559564

  9. Precipitation chemistry and wet deposition in a remote wet savanna site in West Africa: Djougou (Benin)

    NASA Astrophysics Data System (ADS)

    Akpo, A. B.; Galy-Lacaux, C.; Laouali, D.; Delon, C.; Liousse, C.; Adon, M.; Gardrat, E.; Mariscal, A.; Darakpa, C.

    2015-08-01

    In the framework of the IDAF (IGAC/DEBITS/AFrica) international program, this study aims to study the chemical composition of precipitation and associated wet deposition at the rural site of Djougou in Benin, representative of a West and Central African wet savanna. Five hundred and thirty rainfall samples were collected at Djougou, Benin, from July 2005 to December 2009 to provide a unique database. The chemical composition of precipitation was analyzed for inorganic (Ca2+, Mg2+, Na+, NH4+, K+, NO3-, Cl-, SO42-) and organic (HCOO-, CH3COO-, C2H5COO-, C2O42-) ions, using ion chromatography. The 530 collected rain events represent a total of 5706.1 mm of rainfall compared to the measured pluviometry 6138.9 mm, indicating that the collection efficiency is about 93%. The order of total annual loading rates for soluble cations is NH4+ > Ca2+ > Mg2+ > K+. For soluble anions the order of loading is carbonates > HCOO- > NO3- > CH3COO- > SO4,SUP>2- > Cl- > C2O42- > C2H5COO-. In the wet savanna of Djougou, 86% of the measured pH values range between 4.7 and 5.7 with a median pH of 5.19, corresponding to a VWM (Volume Weighed Mean) H+ concentration of 6.46 μeq·L-1. This acidity results from a mixture of mineral and organic acids. The annual sea salt contribution was computed for K+, Mg2+, Ca2+ and SO42- and represents 4.2% of K+, 41% of Mg2+, 1.3% of Ca2+, and 7.4% of SO42-. These results show that K+, Ca2+, SO42-, and Mg2+ were mainly of non-marine origin. The marine contribution is estimated at 9%. The results of the chemical composition of rainwater of Djougou indicates that, except for the carbonates, ammonium has the highest VWM concentration (14.3 μeq·L-1) and nitrate concentration is 8.2 μeq·L-1. The distribution of monthly VWM concentration for all ions is computed and shows the highest values during the dry season, comparing to the wet season. Identified nitrogenous compound sources (NOx and NH3) are domestic animals, natural emissions from savanna soils

  10. Zika virus outside Africa.

    PubMed

    Hayes, Edward B

    2009-09-01

    Zika virus (ZIKV) is a flavivirus related to yellow fever, dengue, West Nile, and Japanese encephalitis viruses. In 2007 ZIKV caused an outbreak of relatively mild disease characterized by rash, arthralgia, and conjunctivitis on Yap Island in the southwestern Pacific Ocean. This was the first time that ZIKV was detected outside of Africa and Asia. The history, transmission dynamics, virology, and clinical manifestations of ZIKV disease are discussed, along with the possibility for diagnostic confusion between ZIKV illness and dengue.The emergence of ZIKV outside of its previously known geographic range should prompt awareness of the potential for ZIKV to spread to other Pacific islands and the Americas.

  11. The relationship between African easterly waves and daily rainfall over West Africa: observations and regional climate simulations

    NASA Astrophysics Data System (ADS)

    Crétat, Julien; Vizy, Edward K.; Cook, Kerry H.

    2015-01-01

    The relationship between summer African easterly waves (AEWs) and daily rainfall is assessed in West Africa for 1998-2008 using various reanalyses, satellite-derived rainfall products, and a regional climate model (RCM) run at 90- and 30-km resolutions. 3-5 and 6-9 day AEWs are extracted by filtering daily 700 hPa meridional wind time series at 1°W and 11.5°N, and 1°W and 17.5°N, respectively. Both observed and simulated rainfall anomalies are of larger magnitude over West Africa during 3-5-d than 6-9-d AEWs. The RCM simulates larger rainfall rates in phase with the 3-5-d wave trough instead of ahead, unlike the observations, and overestimates the intensity and spatial coverage of rainfall associated with 6-9-d AEWs. The observed and simulated co-variability between 3-5-d (6-9-d) AEW activity and daily rainfall is strong (weak) and mostly located south (north) of 15°N. However, the RCM overestimates the spatial coverage of the AEW-rainfall relationship in the longitudinal (latitudinal) direction in the case of 3-5-d (6-9-d) AEWs. Observed and simulated daily intense rainfall events, extracted using a percentile threshold approach, are mostly located south of 15°N during summer. The observed relationship between their frequency of occurrence and active 3-5-d AEWs is maximal west of 8°E, while extends up to southern Chad in both RCM simulations. Their magnitude is also largely overestimated by the RCM, indicating an exaggerated coupling between the wave activity and the convection. Finally, observed and simulated 3-5-d AEWs establish the most favorable synoptic conditions for the development of intense rainfall events over West Africa.

  12. Water balance estimation with the Budyko method to assess the hydropower potential of rivers in West Africa

    NASA Astrophysics Data System (ADS)

    Kling, Harald; Stanzel, Philipp; Fuchs, Martin

    2015-04-01

    Small and medium hydropower has a large potential for future development in West Africa, a region that is facing a constant shortage of energy supply and thereby limiting economic growth. The river reaches suitable for small and medium hydropower development are usually located in headwater areas. Mean annual discharge (along with slope) is a key variable for assessing the hydropower potential of a river reach. As discharge gauges are typically located at larger, downstream rivers a regionalization of flow is required. In this study we use the Budyko method to establish the spatially distributed mean annual water balance for whole West Africa (appr. 5 Mio km²), including the basins of e.g. Niger, Volta, and Senegal rivers. The spatially distributed inputs of mean annual precipitation and potential evapotranspiration are used to compute actual evapotranspiration and thus runoff. Runoff is aggregated along the river network to compute discharge. Due to the impact of different soils and vegetation cover the Budyko curve is calibrated with observed discharge data of about 100 basins covering a wide range of humid to semi-arid conditions. A framework is developed to properly account for the distinctive decadal variations of rainfall (and discharge) in West Africa. Specific challenges are (a) apparently biased discharge measurements at some gauges and (b) uncertainties in the precipitation data (station-based and satellite-based). The results of this study will give (1) an overview about the hydropower potential in each West African country and (2) the theoretical hydropower potential of about 100,000 river reaches. The results will be published on a website with interactive maps to enable the selection of regions of interest for further, detailed assessment of small and medium hydropower development.

  13. Ebola or Not? Evaluating the Ill Traveler From Ebola-Affected Countries in West Africa

    PubMed Central

    Fairley, Jessica K.; Kozarsky, Phyllis E.; Kraft, Colleen S.; Guarner, Jeannette; Steinberg, James P.; Anderson, Evan; Jacob, Jesse T.; Meloy, Patrick; Gillespie, Darria; Espinoza, Tamara R.; Isakov, Alexander; Vanairsdale, Sharon; Baker, Esther; Wu, Henry M.

    2016-01-01

    Background. The 2014–2015 Ebola epidemic in West Africa had global impact beyond the primarily affected countries of Guinea, Liberia, and Sierra Leone. Other countries, including the United States, encountered numerous patients who arrived from highly affected countries with fever or other signs or symptoms consistent with Ebola virus disease (EVD). Methods. We describe our experience evaluating 25 travelers who met the US Centers for Disease Control and Prevention case definition for a person under investigation (PUI) for EVD from July 20, 2014 to January 28, 2015. All patients were triaged and evaluated under the guidance of institutional protocols to the emergency department, outpatient tropical medicine clinic, or Emory's Ebola treatment unit. Strict attention to infection control and early involvement of public health authorities guided the safe evaluation of these patients. Results. None were diagnosed with EVD. Respiratory illnesses were common, and 8 (32%) PUI were confirmed to have influenza. Four patients (16%) were diagnosed with potentially life-threatening infections or conditions, including 3 with Plasmodium falciparum malaria and 1 with diabetic ketoacidosis. Conclusions. In addition to preparing for potential patients with EVD, Ebola assessment centers should consider other life-threatening conditions requiring urgent treatment, and travelers to affected countries should be strongly advised to seek pretravel counseling. Furthermore, attention to infection control in all aspects of PUI evaluation is paramount and has presented unique challenges. Lessons learned from our evaluation of potential patients with EVD can help inform preparations for future outbreaks of highly pathogenic communicable diseases. PMID:26925428

  14. Ebola or Not? Evaluating the Ill Traveler From Ebola-Affected Countries in West Africa.

    PubMed

    Fairley, Jessica K; Kozarsky, Phyllis E; Kraft, Colleen S; Guarner, Jeannette; Steinberg, James P; Anderson, Evan; Jacob, Jesse T; Meloy, Patrick; Gillespie, Darria; Espinoza, Tamara R; Isakov, Alexander; Vanairsdale, Sharon; Baker, Esther; Wu, Henry M

    2016-01-01

    Background.  The 2014-2015 Ebola epidemic in West Africa had global impact beyond the primarily affected countries of Guinea, Liberia, and Sierra Leone. Other countries, including the United States, encountered numerous patients who arrived from highly affected countries with fever or other signs or symptoms consistent with Ebola virus disease (EVD). Methods.  We describe our experience evaluating 25 travelers who met the US Centers for Disease Control and Prevention case definition for a person under investigation (PUI) for EVD from July 20, 2014 to January 28, 2015. All patients were triaged and evaluated under the guidance of institutional protocols to the emergency department, outpatient tropical medicine clinic, or Emory's Ebola treatment unit. Strict attention to infection control and early involvement of public health authorities guided the safe evaluation of these patients. Results.  None were diagnosed with EVD. Respiratory illnesses were common, and 8 (32%) PUI were confirmed to have influenza. Four patients (16%) were diagnosed with potentially life-threatening infections or conditions, including 3 with Plasmodium falciparum malaria and 1 with diabetic ketoacidosis. Conclusions.  In addition to preparing for potential patients with EVD, Ebola assessment centers should consider other life-threatening conditions requiring urgent treatment, and travelers to affected countries should be strongly advised to seek pretravel counseling. Furthermore, attention to infection control in all aspects of PUI evaluation is paramount and has presented unique challenges. Lessons learned from our evaluation of potential patients with EVD can help inform preparations for future outbreaks of highly pathogenic communicable diseases.

  15. The contribution of occult precipitation to nutrient deposition on the west coast of South Africa.

    PubMed

    Nyaga, Justine M; Neff, Jason C; Cramer, Michael D

    2015-01-01

    The Strandveld mediterranean-ecosystem of the west coast of South Africa supports floristically diverse vegetation growing on mostly nutrient-poor aeolian sands and extending from the Atlantic Ocean tens of kilometers inland. The cold Benguela current upwelling interacts with warm onshore southerly winds in summer causing coastal fogs in this region. We hypothesized that fog and other forms of occult precipitation contribute moisture and nutrients to the vegetation. We measured occult precipitation over one year along a transect running inland in the direction of the prevailing wind and compared the nutrient concentrations with those in rainwater. Occult deposition rates of P, N, K, Mg, Ca, Na, Al and Fe all decreased with distance from the ocean. Furthermore, ratios of cations to Na were similar to those of seawater, suggesting a marine origin for these. In contrast, N and P ratios in occult precipitation were higher than in seawater. We speculate that this is due to marine foam contributing to occult precipitation. Nutrient loss in leaf litter from dominant shrub species was measured to indicate nutrient demand. We estimated that occult precipitation could meet the demand of the dominant shrubby species for annual N, P, K and Ca. Of these species, those with small leaves intercepted more moisture and nutrients than those with larger leaves and could take up foliar deposits of glycine, NO3(-), NH4(+) and Li (as tracer for K) through leaf surfaces. We conclude that occult deposition together with rainfall deposition are potentially important nutrient and moisture sources for the Strandveld vegetation that contribute to this vegetation being floristically distinct from neighbouring nutrient-poor Fynbos vegetation.

  16. The Contribution of Occult Precipitation to Nutrient Deposition on the West Coast of South Africa

    PubMed Central

    2015-01-01

    The Strandveld mediterranean-ecosystem of the west coast of South Africa supports floristically diverse vegetation growing on mostly nutrient-poor aeolian sands and extending from the Atlantic Ocean tens of kilometers inland. The cold Benguela current upwelling interacts with warm onshore southerly winds in summer causing coastal fogs in this region. We hypothesized that fog and other forms of occult precipitation contribute moisture and nutrients to the vegetation. We measured occult precipitation over one year along a transect running inland in the direction of the prevailing wind and compared the nutrient concentrations with those in rainwater. Occult deposition rates of P, N, K, Mg, Ca, Na, Al and Fe all decreased with distance from the ocean. Furthermore, ratios of cations to Na were similar to those of seawater, suggesting a marine origin for these. In contrast, N and P ratios in occult precipitation were higher than in seawater. We speculate that this is due to marine foam contributing to occult precipitation. Nutrient loss in leaf litter from dominant shrub species was measured to indicate nutrient demand. We estimated that occult precipitation could meet the demand of the dominant shrubby species for annual N, P, K and Ca. Of these species, those with small leaves intercepted more moisture and nutrients than those with larger leaves and could take up foliar deposits of glycine, NO3-, NH4+ and Li (as tracer for K) through leaf surfaces. We conclude that occult deposition together with rainfall deposition are potentially important nutrient and moisture sources for the Strandveld vegetation that contribute to this vegetation being floristically distinct from neighbouring nutrient-poor Fynbos vegetation. PMID:26017747

  17. Temporal and spatial analysis of the 2014-2015 Ebola virus outbreak in West Africa.

    PubMed

    Carroll, Miles W; Matthews, David A; Hiscox, Julian A; Elmore, Michael J; Pollakis, Georgios; Rambaut, Andrew; Hewson, Roger; García-Dorival, Isabel; Bore, Joseph Akoi; Koundouno, Raymond; Abdellati, Saïd; Afrough, Babak; Aiyepada, John; Akhilomen, Patience; Asogun, Danny; Atkinson, Barry; Badusche, Marlis; Bah, Amadou; Bate, Simon; Baumann, Jan; Becker, Dirk; Becker-Ziaja, Beate; Bocquin, Anne; Borremans, Benny; Bosworth, Andrew; Boettcher, Jan Peter; Cannas, Angela; Carletti, Fabrizio; Castilletti, Concetta; Clark, Simon; Colavita, Francesca; Diederich, Sandra; Donatus, Adomeh; Duraffour, Sophie; Ehichioya, Deborah; Ellerbrok, Heinz; Fernandez-Garcia, Maria Dolores; Fizet, Alexandra; Fleischmann, Erna; Gryseels, Sophie; Hermelink, Antje; Hinzmann, Julia; Hopf-Guevara, Ute; Ighodalo, Yemisi; Jameson, Lisa; Kelterbaum, Anne; Kis, Zoltan; Kloth, Stefan; Kohl, Claudia; Korva, Miša; Kraus, Annette; Kuisma, Eeva; Kurth, Andreas; Liedigk, Britta; Logue, Christopher H; Lüdtke, Anja; Maes, Piet; McCowen, James; Mély, Stéphane; Mertens, Marc; Meschi, Silvia; Meyer, Benjamin; Michel, Janine; Molkenthin, Peter; Muñoz-Fontela, César; Muth, Doreen; Newman, Edmund N C; Ngabo, Didier; Oestereich, Lisa; Okosun, Jennifer; Olokor, Thomas; Omiunu, Racheal; Omomoh, Emmanuel; Pallasch, Elisa; Pályi, Bernadett; Portmann, Jasmine; Pottage, Thomas; Pratt, Catherine; Priesnitz, Simone; Quartu, Serena; Rappe, Julie; Repits, Johanna; Richter, Martin; Rudolf, Martin; Sachse, Andreas; Schmidt, Kristina Maria; Schudt, Gordian; Strecker, Thomas; Thom, Ruth; Thomas, Stephen; Tobin, Ekaete; Tolley, Howard; Trautner, Jochen; Vermoesen, Tine; Vitoriano, Inês; Wagner, Matthias; Wolff, Svenja; Yue, Constanze; Capobianchi, Maria Rosaria; Kretschmer, Birte; Hall, Yper; Kenny, John G; Rickett, Natasha Y; Dudas, Gytis; Coltart, Cordelia E M; Kerber, Romy; Steer, Damien; Wright, Callum; Senyah, Francis; Keita, Sakoba; Drury, Patrick; Diallo, Boubacar; de Clerck, Hilde; Van Herp, Michel; Sprecher, Armand; Traore, Alexis; Diakite, Mandiou; Konde, Mandy Kader; Koivogui, Lamine; Magassouba, N'Faly; Avšič-Županc, Tatjana; Nitsche, Andreas; Strasser, Marc; Ippolito, Giuseppe; Becker, Stephan; Stoecker, Kilian; Gabriel, Martin; Raoul, Hervé; Di Caro, Antonino; Wölfel, Roman; Formenty, Pierre; Günther, Stephan

    2015-08-06

    West Africa is currently witnessing the most extensive Ebola virus (EBOV) outbreak so far recorded. Until now, there have been 27,013 reported cases and 11,134 deaths. The origin of the virus is thought to have been a zoonotic transmission from a bat to a two-year-old boy in December 2013 (ref. 2). From this index case the virus was spread by human-to-human contact throughout Guinea, Sierra Leone and Liberia. However, the origin of the particular virus in each country and time of transmission is not known and currently relies on epidemiological analysis, which may be unreliable owing to the difficulties of obtaining patient information. Here we trace the genetic evolution of EBOV in the current outbreak that has resulted in multiple lineages. Deep sequencing of 179 patient samples processed by the European Mobile Laboratory, the first diagnostics unit to be deployed to the epicentre of the outbreak in Guinea, reveals an epidemiological and evolutionary history of the epidemic from March 2014 to January 2015. Analysis of EBOV genome evolution has also benefited from a similar sequencing effort of patient samples from Sierra Leone. Our results confirm that the EBOV from Guinea moved into Sierra Leone, most likely in April or early May. The viruses of the Guinea/Sierra Leone lineage mixed around June/July 2014. Viral sequences covering August, September and October 2014 indicate that this lineage evolved independently within Guinea. These data can be used in conjunction with epidemiological information to test retrospectively the effectiveness of control measures, and provides an unprecedented window into the evolution of an ongoing viral haemorrhagic fever outbreak.

  18. Ecosystem properties of semiarid savanna grassland in West Africa and its relationship with environmental variability.

    PubMed

    Tagesson, Torbern; Fensholt, Rasmus; Guiro, Idrissa; Rasmussen, Mads Olander; Huber, Silvia; Mbow, Cheikh; Garcia, Monica; Horion, Stéphanie; Sandholt, Inge; Holm-Rasmussen, Bo; Göttsche, Frank M; Ridler, Marc-Etienne; Olén, Niklas; Lundegard Olsen, Jørgen; Ehammer, Andrea; Madsen, Mathias; Olesen, Folke S; Ardö, Jonas

    2015-01-01

    The Dahra field site in Senegal, West Africa, was established in 2002 to monitor ecosystem properties of semiarid savanna grassland and their responses to climatic and environmental change. This article describes the environment and the ecosystem properties of the site using a unique set of in situ data. The studied variables include hydroclimatic variables, species composition, albedo, normalized difference vegetation index (NDVI), hyperspectral characteristics (350-1800 nm), surface reflectance anisotropy, brightness temperature, fraction of absorbed photosynthetic active radiation (FAPAR), biomass, vegetation water content, and land-atmosphere exchanges of carbon (NEE) and energy. The Dahra field site experiences a typical Sahelian climate and is covered by coexisting trees (~3% canopy cover) and grass species, characterizing large parts of the Sahel. This makes the site suitable for investigating relationships between ecosystem properties and hydroclimatic variables for semiarid savanna ecosystems of the region. There were strong interannual, seasonal and diurnal dynamics in NEE, with high values of ~-7.5 g C m(-2)  day(-1) during the peak of the growing season. We found neither browning nor greening NDVI trends from 2002 to 2012. Interannual variation in species composition was strongly related to rainfall distribution. NDVI and FAPAR were strongly related to species composition, especially for years dominated by the species Zornia glochidiata. This influence was not observed in interannual variation in biomass and vegetation productivity, thus challenging dryland productivity models based on remote sensing. Surface reflectance anisotropy (350-1800 nm) at the peak of the growing season varied strongly depending on wavelength and viewing angle thereby having implications for the design of remotely sensed spectral vegetation indices covering different wavelength regions. The presented time series of in situ data have great potential for dryland dynamics

  19. Calculating crop water requirement satisfaction in the West Africa Sahel with remotely sensed soil moisture

    USGS Publications Warehouse

    McNally, Amy; Gregory J. Husak,; Molly Brown,; Mark Carroll,; Funk, Christopher C.; Soni Yatheendradas,; Kristi Arsenault,; Christa Peters-Lidard,; Verdin, James

    2015-01-01

    The Soil Moisture Active Passive (SMAP) mission will provide soil moisture data with unprecedented accuracy, resolution, and coverage, enabling models to better track agricultural drought and estimate yields. In turn, this information can be used to shape policy related to food and water from commodity markets to humanitarian relief efforts. New data alone, however, do not translate to improvements in drought and yield forecasts. New tools will be needed to transform SMAP data into agriculturally meaningful products. The objective of this study is to evaluate the possibility and efficiency of replacing the rainfall-derived soil moisture component of a crop water stress index with SMAP data. The approach is demonstrated with 0.1°-resolution, ~10-day microwave soil moisture from the European Space Agency and simulated soil moisture from the Famine Early Warning Systems Network Land Data Assimilation System. Over a West Africa domain, the approach is evaluated by comparing the different soil moisture estimates and their resulting Water Requirement Satisfaction Index values from 2000 to 2010. This study highlights how the ensemble of indices performs during wet versus dry years, over different land-cover types, and the correlation with national-level millet yields. The new approach is a feasible and useful way to quantitatively assess how satellite-derived rainfall and soil moisture track agricultural water deficits. Given the importance of soil moisture in many applications, ranging from agriculture to public health to fire, this study should inspire other modeling communities to reformulate existing tools to take advantage of SMAP data.

  20. Sediment budget of cratons: insights from West Africa over the Cenozoic

    NASA Astrophysics Data System (ADS)

    Jean-Louis, G.; Chardon, D.; Rouby, D.; Beauvais, A.

    2015-12-01

    The sediment load of rivers constitutes the material that builds the stratigraphic successions found from continental margins to the deep ocean. Measure of this flux is relevant to understanding continental controls on denudation, riverine transport and basin filling. An increasing number of sediment yield measures is available but whether these modern values can be extrapolated at geological timescales for large watersheds is still questioned. One reason is the lack of long-term data. Here, we present a sediment budget for Sub-Saharan West Africa over the Cenozoic to compare with the modern rates. The denudation of this cratonic area is constrained using three regional lateritic paleo-landsurfaces that formed during periods of enhanced weathering since the Paleocene-Eocene greenhouse peak. The 3D interpolation of these surfaces allowed building three successive denudation maps for the 45-24, 24-11 and 11-0 Ma intervals together with reconstructions of the paleo-drainage. The regional distribution of erosion suggests the influence of lithospheric deformation, concentrated around a southern marginal upwarp and eastern hotspot swells. The export of large-scale drainages was calculated by converting denudated volumes into sediment fluxes using the porosity and density of lateritic regolith. Exported volumes calculated for the Niger watershed fall within the same range as the Cenozoic clastic accumulations of the Niger delta. Comparisons also show that modern fluxes can be an order of magnitude above the long-term fluxes for moderately large watersheds but that modern and long-term yields are similar for the largest watersheds (e.g. Niger, Volta, Senegal). These results suggest that the export of very large cratonic watersheds is independent of the measurement timescale and that their modern yields can be extrapolated at long-timescale. Finally, it allows assessing the relative contribution of cratons, i.e. non-active orogenic areas, to the global sediment budgets at

  1. Dictating participation? Rethinking the adaptive co-management of socio-ecological systems in West Africa

    NASA Astrophysics Data System (ADS)

    El Vilaly, Audra; Abd salam El Vilaly, Mohamed

    2015-04-01

    In the face of environmental change, enhancing adaptive capacity relies on stakeholder engagement. But the participatory process, while critical to the translation, transfer, and application of scientific knowledge to society, is not without its own contradictions. These include the asymmetrical relations of power that prevail between environmental scientists, managers, and local users; discrepant understandings of knowledge and its appropriate uses; and conflicting social, economic, and ecological values, to name only a few. Our research examines five major transboundary river basin organizations in West Africa and their efforts to improve adaptive basin management via stakeholder collaboration. In particular, we evaluate the participatory strategies of these organizations to measure non-linear, multi-directional feedbacks between the social and biophysical factors of land use/land cover change, as well as the impacts of this change on basins and their dependent populations. Our research suggests that oftentimes, these methods paradoxically produce a hierarchical and marginalizing effect on local stakeholders in relation to the scientists that study them. In seeking to address these limitations, we assess the potential costs and benefits of integrating select components of a Participatory Action Research (PAR) framework (see, for example, Reason & Bradbury-Huang, 2007) into studies of complex socio-ecological problems. This approach, used widely in the social sciences, promotes critical reflection on and minimization of the power inequities inherent in science-society collaborations. It instead favors more horizontal forms of knowledge co-production that support and foster the expansion of local, existing movements for social and environmental justice. A PAR framework may therefore improve the efficiency, sustainability, and equitability of land-based adaptation to environmental change; further research is thus recommended to test this hypothesis. References

  2. Petrology and chemistry of the basaltic shergottite North West Africa 480

    NASA Astrophysics Data System (ADS)

    Barrat, J. A.; Gillet, Ph.; Sautter, V.; Jambon, A.; Javoy, M.; Göpel, C.; Lesourd, M.; Keller, F.; Petit, E.

    2002-04-01

    North West Africa (NWA) 480 is a new martian meteorite of 28 g found in the Moroccan Sahara in November 2000. It consists mainly of large gray pyroxene crystals (the largest grains are up to 5 mm in length) and plagioclase converted to maskelynite. Excluding the melt pocket areas, modal analyses indicate the following mineral proportions: 72 vol% pyroxenes extensively zoned, 25% maskelynite, 1% phosphates (merrillite and chlorapatite), 1% opaque oxides (ilmenite, ulvospinel and chromite) and sulfides, and 1% others such as silica and fayalite. The compositional trend of NWA 480 pyroxenes is similar to that of Queen Alexandra Range (QUE) 94201 but in NWA 480 the pyroxene cores are more Mg-rich (En77-En65). Maskelynites display a limited zoning (An42-50Ab54-48Or2-4). Our observations suggest that NWA 480 formed from a melt with a low nuclei density at a slow cooling rate. The texture was achieved via a single-stage cooling where pyroxenes grew continuously. A similar model was previously proposed for QUE 94201 by McSween et al. (1996). NWA 480 is an Al-poor ferroan basaltic rock and resembles Zagami or Shergotty for major elements and compatible trace element abundances. The bulk rock analysis for oxygen isotopes yields V17O = +0.42%o, a value in agreement at the high margin, with those measured on other shergottites (Clayton and Mayeda, 1996; Romanek et al., 1998; Franchi et al., 1999). Its CI-normalized rare earth element pattern is similar to those of peridotitic shergottites such as Allan Hills (ALH)A77005, suggesting that these shergottites shared a similar parent liquid, or at least the same mantle source.

  3. Analysis of Hydrological Processes In A Small Catchment In Benin (west Africa)

    NASA Astrophysics Data System (ADS)

    Giertz, S.; Diekkrüger, B.

    The presented study is integrated in the GLOWA IMPETUS project (an integrated ap- proach to the efficient management of scarce water resources in West Africa) which analyses the effects of global change conditions on regional hydrological processes and on the water availability in Benin and Morocco. To examine the hydrological cy- cle and its change at the regional scale, detailed knowledge about the dominant hydro- logical processes dependent on the environmental conditions is necessary. This study provides the analysis of the hydrological processes as well as their simulation at the local scale serving as a basis for the subsequent regionalisation of processes and model parameters. The investigated area is a 30 km2 sized catchment in the sub-humid region of Benin which has been selected as research area for several participating disciplines of the IMPETUS-Project (hydrology, soil degradation, dynamics of vegetation, phys- iological plant ecology). The catchment is characterized by a high spatial variability of the land cover and a high temporal variablility due to land cover changes. Con- sequently all hydrologic measurements are performed on different land use types to analyse their influence on the hydrological processes. The measurements of soil water dynamics, runoff, infiltration and soil physical properties provide detailed information on the generation of model input parameters. A validation of the model output is car- ried out by comparing simulated and measured dynamics of state variables as well as water balance terms. By testing and validating the TOPLATS-model at the local scale in different-sized sub-catchments an evaluation of its applicability to the regional scale and the assessment of the related uncertainties is performed.

  4. An Analysis of the Environments of Intense Convective Systems in West Africa in 2003

    NASA Technical Reports Server (NTRS)

    Nicholls, Stephen D.; Mohr, Karen I.

    2010-01-01

    We investigated the local- and regional-scale thermodynamical and dynamical environments associated with intense convective systems in West Africa during 2003. We identified convective system cases from TRMM microwave imagery, classifying each case by the system minimum 85-GHz brightness temperature and by the estimated elapsed time of propagation from high terrain. The speed of the mid-level jet, the magnitude of the low-level shear, and the surface equivalent potential temperature (theta(sub e)) were greater for the intense cases compared to the non-intense cases, although the differences between the means tended to be small, less than 3K for surface theta(sub e). Hypothesis testing of a series of commonly used intensity prediction metrics resulted in significant results only for low-level metrics such as convective available potential energy and not for any of the mid- or upper-level metrics such as 700-hPa theta(sub e). None of the environmental variables or intensity metrics by themselves or in combination appeared to be reliable direct predictors of intensity. In the regional scale analysis, the majority of intense convective systems occurred in the surface baroclinic zone where surface theta(sub e) exceeded 344 K and the 700-hPa zonal wind speeds were less than -6/ms. Fewer intense cases compared to non-intense cases were associated with African easterly wave troughs. Fewer than 25% of our cases occurred in environments with detectable Saharan dust loads, and the results for intense and non-intense cases were similar. Our results for the regional analysis were consistent with the seasonal movement of the WAM and the intertropical front, regional differences in topography, and AEW energetics.

  5. Studies of 21st-Century Precipitation Trends Over West Africa

    NASA Technical Reports Server (NTRS)

    Druyan, Leonard M.

    2010-01-01

    West Africa includes a semi-arid zone between the Sahara Desert and the humid Gulf of Guinea coast, approximately between 10 N and 20 N, which is irrigated by summer monsoon rains. This article refers to the region as the Sahel. Rain-fed agriculture is the primary sustenance for Sahel populations, and severe droughts (in the 1970s and 1980s), therefore, have devastating negative societal impacts. The future frequency of Sahel droughts and the evolution of its hydrological balance are therefore of great interest. The article reviews 10 recent research studies that attempt to discover how climate changes will affect the hydrology of the Sahel throughout the 21st century. All 10 studies rely on atmosphere ocean global climate model (AOGCM) simulations based on a range of greenhouse gas emissions scenarios. Many of the simulations are contained in the Intergovernmental Panel on Climate Change archives for Assessment Reports #3 and #4. Two of the studies use AOGCM data to drive regional climate models. Seven studies make projections for the first half of the 21st century and eight studies make projections for the second half. Some studies make projections of wetter conditions and some predict more frequent droughts, and each describes the atmospheric processes associated with its prediction. Only one study projects more frequent droughts before 2050, and that is only for continent-wide degradation in vegetation cover. The challenge to correctly simulate Sahel rainfall decadal trends is particularly daunting because multiple physical mechanisms compete to drive the trend upwards or downwards. A variety of model deficiencies, regarding the simulation of one or more of these physical processes, taints models climate change projections. Consequently, no consensus emerges regarding the impact of anticipated greenhouse gas forcing on the hydrology of the Sahel in the second half of the 21st century.

  6. How model and input uncertainty impact maize yield simulations in West Africa

    NASA Astrophysics Data System (ADS)

    Waha, Katharina; Huth, Neil; Carberry, Peter; Wang, Enli

    2015-02-01

    Crop models are common tools for simulating crop yields and crop production in studies on food security and global change. Various uncertainties however exist, not only in the model design and model parameters, but also and maybe even more important in soil, climate and management input data. We analyze the performance of the point-scale crop model APSIM and the global scale crop model LPJmL with different climate and soil conditions under different agricultural management in the low-input maize-growing areas of Burkina Faso, West Africa. We test the models’ response to different levels of input information from little to detailed information on soil, climate (1961-2000) and agricultural management and compare the models’ ability to represent the observed spatial (between locations) and temporal variability (between years) in crop yields. We found that the resolution of different soil, climate and management information influences the simulated crop yields in both models. However, the difference between models is larger than between input data and larger between simulations with different climate and management information than between simulations with different soil information. The observed spatial variability can be represented well from both models even with little information on soils and management but APSIM simulates a higher variation between single locations than LPJmL. The agreement of simulated and observed temporal variability is lower due to non-climatic factors e.g. investment in agricultural research and development between 1987 and 1991 in Burkina Faso which resulted in a doubling of maize yields. The findings of our study highlight the importance of scale and model choice and show that the most detailed input data does not necessarily improve model performance.

  7. Regional Climate Change Impact on Agricultural Land Use in West Africa

    NASA Astrophysics Data System (ADS)

    Ahmed, K. F.; Wang, G.; You, L.

    2014-12-01

    Agriculture is a key element of the human-induced land use land cover change (LULCC) that is influenced by climate and can potentially influence regional climate. Temperature and precipitation directly impact the crop yield (by controlling photosynthesis, respiration and other physiological processes) that then affects agricultural land use pattern. In feedback, the resulting changes in land use and land cover play an important role to determine the direction and magnitude of global, regional and local climate change by altering Earth's radiative equilibrium. The assessment of future agricultural land use is, therefore, of great importance in climate change study. In this study, we develop a prototype land use projection model and, using this model, project the changes to land use pattern and future land cover map accounting for climate-induced yield changes for major crops in West Africa. Among the inputs to the land use projection model are crop yield changes simulated by the crop model DSSAT, driven with the climate forcing data from the regional climate model RegCM4.3.4-CLM4.5, which features a projected decrease of future mean crop yield and increase of inter-annual variability. Another input to the land use projection model is the projected changes of food demand in the future. In a so-called "dumb-farmer scenario" without any adaptation, the combined effect of decrease in crop yield and increase in food demand will lead to a significant increase in agricultural land use in future years accompanied by a decrease in forest and grass area. Human adaptation through land use optimization in an effort to minimize agricultural expansion is found to have little impact on the overall areas of agricultural land use. While the choice of the General Circulation Model (GCM) to derive initial and boundary conditions for the regional climate model can be a source of uncertainty in projecting the future LULCC, results from sensitivity experiments indicate that the changes

  8. Impact of future climate change on streamflow in the White Volta river basin, West Africa

    NASA Astrophysics Data System (ADS)

    Obuobie, E.; Diekkrüger, B.; Liebe, J.

    2009-04-01

    The Soil and Water Assessment Tool (SWAT) model was applied in the White Volta river basin, West Africa, to simulate the streamflow and to estimate the impact of future climate change on the streamflow. The White Volta river basin is one of the three major sub-basins of the Volta river basin, and drains an area of about 106,000 km2 mainly shared by the riparian countries, Burkina Faso and Ghana. The model was calibrated and validated using daily measured streamflow data from the stream gage at Nawuni, for the period 1980-2000. Impact of future climate change on streamflow was estimated by simulating streamflow of two time slices, the present (1990-2000) and future (2030-2039), using the calibrated SWAT model and stochastically generated daily climate series and comparing their mean annual values. The generated future climate series reflected monthly changes in precipitation and temperature forecasted by the meso-scale climate model MM5, which was downscaled from ECHAM4 scenario IS92a. The results show that SWAT is able to accurately reproduce the streamflow in the White Volta Basin. The coefficient of determination and Nash-Sutcliffe model efficiency were found to be, respectively, higher than 0.8 and 0.7, for both the calibration and validation periods. Compared to the present, the future mean annual streamflow and the annual coefficient of variation of the streamflow in the basin are expected to increase by 33% and 52%, respectively, as a result of future climate change.

  9. Monthly streamflow prediction in the Volta Basin of West Africa: A SISO NARMAX polynomial modelling

    NASA Astrophysics Data System (ADS)

    Amisigo, B. A.; van de Giesen, N.; Rogers, C.; Andah, W. E. I.; Friesen, J.

    Single-input-single-output (SISO) non-linear system identification techniques were employed to model monthly catchment runoff at selected gauging sites in the Volta Basin of West Africa. NARMAX (Non-linear Autoregressive Moving Average with eXogenous Input) polynomial models were fitted to basin monthly rainfall and gauging station runoff data for each of the selected sites and used to predict monthly runoff at the sites. An error reduction ratio (ERR) algorithm was used to order regressors for various combinations of input, output and noise lags (various model structures) and the significant regressors for each model selected by applying an Akaike Information Criterion (AIC) to independent rainfall-runoff validation series. Model parameters were estimated from the Matlab REGRESS function (an orthogonal least squares method). In each case, the sub-model without noise terms was fitted first followed by a fitting of the noise model. The coefficient of determination ( R-squared), the Nash-Sutcliffe Efficiency criterion (NSE) and the F statistic for the estimation (training) series were used to evaluate the significance of fit of each model to this series while model selection from the range of models fitted for each gauging site was done by examining the NSEs and the AICs of the validation series. Monthly runoff predictions from the selected models were very good, and the polynomial models appeared to have captured a good part of the rainfall-runoff non-linearity. The results indicate that the NARMAX modelling framework is suitable for monthly river runoff prediction in the Volta Basin. The several good models made available by the NARMAX modelling framework could be useful in the selection of model structures that also provide insights into the physical behaviour of the catchment rainfall-runoff system.

  10. [Organisation of Veterinary Services in the developing countries of West Africa].

    PubMed

    Coulibaly, H

    2004-04-01

    The Veterinary Services in West Africa focused on animal health and production activities, which up until the beginning of the 1990s, were exclusively their responsibility. They were supported by many projects, conducted with notable successes. Veterinary public health activities were considered to be less of a priority because the major objective was improving productivity and because the concept of food safety was perceived by stakeholders to be much less important. The major challenges and issues that the weakened Veterinary Services will have to face are complying with the requirements of the World Trade Organization, negotiating new economic partnership agreements and dealing with the consequences of the implementation of structural adjustment programmes in the agricultural sector. The reorganisation of these Services is therefore taking place in the context of the globalisation of health problems, and in a trading framework that requires the application of the current international standards and regulations. Veterinary Services and their governments will have to meet these challenges by initiating discussions that lead to effective operational structures that can implement public health measures, satisfy the expectations of consumers and partner countries and withstand assessment by other countries. However, such reform depends upon several factors, such as a demonstration of political will, the development of an approach based on regional economic unions, and the indispensable support of financial backers. To add to the debate, the author offers recommendations and guidelines on the institutional framework, veterinary personnel and equipment and material needs. Creating effective Veterinary Services that have efficient operational structures and procedures is an ongoing process; how long this process takes depends on the ability of Veterinary Services to respond to the various challenges. Underlying these challenges and issues, in this region of the world as

  11. Participatory planning in river catchments, an innovative toolkit tested in Southern Africa and North West England.

    PubMed

    Tippett, J

    2005-01-01

    The European Union Water Framework Directive (WFD) offers an unparalleled opportunity for improving river basin management. Active participation is essential for its delivery. "End-of-pipe" solutions will not deliver the improvements needed to achieve its ambitious goals. This research tested DesignWays, a toolkit for participatory planning, as a mechanism for maximizing the long-term social and environmental benefits of such stakeholder and community participation. It examined the emerging role of "planning for sustainability" in the context of river catchments. Sustainable management of water requires integration, and recognition of interconnections between systems at different levels of scale. This is an endeavour in which systems thinking provides useful tools. The development of DesignWays was a conscious attempt to embed 'new paradigm' living systems metaphors into a practical planning tool. This paper begins with a description of DesignWays and its development in Southern Africa. An outline of the context of the action research in North-West England is followed by a description of the stages of the process, with highlights of the outcomes. This research had two major outcomes: a contribution to theory through an in-depth exploration of the theoretical basis of participatory, ecologically informed design; and a contribution to practice through investigating DesignWays' potential to meet key challenges of the WFD. This research points to the importance of understanding participatory planning as a societal process, aiming to make the process engaging and meaningful. It has pointed to the need to see participatory planning and education for sustainability as an integrated process. It demonstrated the benefits of an iterative process in which planning at the landscape level of scale informs, and is informed by, work at the site level. It has shown that an approach consistent with a living systems paradigm can contribute to the development of more integrated

  12. Optimal feeding systems for small-scale dairy herds in the North West Province, South Africa.

    PubMed

    Manzana, N Patience; McCrindle, Cheryl M E; Sebei, P Julius; Prozesky, Leon

    2014-07-09

    Land redistribution was legislated in 1994; it was designed to resolve historical imbalances inland ownership in South Africa. Between 2002 and 2006, a longitudinal observational studywas conducted with 15 purposively selected small-scale dairy farmers in a land redistributionproject in Central North West Province. Four farmers left the project over the period. For thepurposes of this study, a small-scale dairy farm was defined as a farm that produces less than500 L of milk a day, irrespective of the number of cows or size of the farm. The study wasconducted in three phases. In the first phase, situational analysis using participatory ruralappraisal (PRA) and observation was used to outline the extent of the constraints and designappropriate interventions. Feeds that were used were tested and evaluated. In the secondphase, three different feeding systems were designed from the data obtained from PRA. Thesewere: (1) A semi-intensive farm-based ration using available crops, pastures and crop residueswith minimal rations purchased. (2) An intensive, zero-grazing dairy system using a totalmixed ration. (3) A traditional, extensive or dual-purpose system, where the calf drank fromthe cow until weaning and milking was done only once a day. In the third phase, adoptionwas monitored. By July 2006, all remaining farmers had changed to commercially formulatedrations or licks and the body condition score of the cows had improved. It was concluded thatveterinary extension based on PRA and a holistic systems approach was a good option forsuch complex problems. Mentoring by commercial dairy farmers, veterinary and extensionservices appeared to be viable. Further research should be done to optimise the traditionalmodel of dairy farming, as this was relatively profitable, had a lower risk and was less labourintensive.

  13. Chimpanzees in an anthropogenic landscape: Examining food resources across habitat types at Bossou, Guinea, West Africa.

    PubMed

    Bryson-Morrison, Nicola; Matsuzawa, Tetsuro; Humle, Tatyana

    2016-12-01

    Many primate populations occur outside protected areas in fragmented anthropogenic landscapes. Empirical data on the ecological characteristics that define an anthropogenic landscape are urgently required if conservation initiatives in such environments are to succeed. The main objective of our study was to determine the composition and availability of chimpanzee (Pan troglodytes verus) food resources across fine spatial scales in the anthropogenic landscape of Bossou, Guinea, West Africa. We examined food resources in all habitat types available in the chimpanzees' core area. We surveyed resource composition, structure and heterogeneity (20 m × 20 m quadrats, N = 54) and assessed temporal availability of food from phenology trails (total distance 5951 m; 1073 individual trees) over 1 year (2012-2013). Over half of Bossou consists of regenerating forest and is highly diverse in terms of chimpanzee food species; large fruit bearing trees are rare and confined to primary and riverine forest. Moraceae (mulberries and figs) was the dominant family, trees of which produce drupaceous fruits favored by chimpanzees. The oil palm occurs at high densities throughout and is the only species found in all habitat types except primary forest. Our data suggest that the high densities of oil palm and fig trees, along with abundant terrestrial herbaceous vegetation and cultivars, are able to provide the chimpanzees with widely available resources, compensating for the scarcity of large fruit trees. A significant difference was found between habitat types in stem density/ha and basal area m(2) /ha of chimpanzee food species. Secondary, young secondary, and primary forest emerged as the most important habitat types for availability of food tree species. Our study emphasizes the importance of examining ecological characteristics of an anthropogenic landscape as each available habitat type is unlikely to be equally important in terms of spatial and temporal availability

  14. Missionary Education in Colonial Africa: The Critique of Mary Kingsley.

    ERIC Educational Resources Information Center

    Pearce, Robert

    1988-01-01

    Discussing missionary education in colonial Africa, Pearce examines the ideas of Mary Kingsley, one of the major influences on British thinking towards Africa from the late 1890's. Focusing attention on her educational views, Pearce states that she had influence on all areas of British policy in Africa, and especially West Africa. (GEA)

  15. Assessments for the impact of mineral dust on the meningitis incidence in West Africa

    NASA Astrophysics Data System (ADS)

    Martiny, Nadège; Chiapello, Isabelle

    2013-05-01

    Recently, mineral dust has been suspected to be one of the important environmental risk factor for meningitis epidemics in West Africa. The current study is one of the first which relies on long-term robust aerosol measurements in the Sahel region to investigate the possible impact of mineral dust on meningitis cases (incidence). Sunphotometer measurements, which allow to derive aerosol and humidity parameters, i.e., aerosol optical thickness, Angström coefficient, and precipitable water, are combined with quantitative epidemiological data in Niger and Mali over the 2004-2009 AMMA (African Monsoon Multidisciplinary Analysis) program period. We analyse how the extremely high aerosol loads in this region may influence both the calendar (onset, peaks, end) and the intensity of meningitis. We highlight three distinct periods: (i) from November to December, beginning of the dry season, humidity is weak, there is no dust and no meningitis cases; (ii) from January to April, humidity is still weak, but high dust loads occur in the atmosphere and this is the meningitis season; (iii) from May to October, humidity is high and there is no meningitis anymore, in presence of dust or not, which flow anyway in higher altitudes. More specifically, the onset of the meningitis season is tightly related to mineral dust flowing close to the surface at the very beginning of the year. During the dry, and the most dusty season period, from February to April, each meningitis peak is preceded by a dust peak, with a 0-2 week lead-time. The importance (duration, intensity) of these meningitis peaks seems to be related to that of dust, suggesting that a cumulative effect in dust events may be important for the meningitis incidence. This is not the case for humidity, confirming the special contribution of dust at this period of the year. The end of the meningitis season, in May, coincides with a change in humidity conditions related to the West African Monsoon. These results, which are

  16. Validating modeled soil moisture with in-situ data for agricultural drought monitoring in West Africa

    NASA Astrophysics Data System (ADS)

    McNally, A.; Yatheendradas, S.; Jayanthi, H.; Funk, C. C.; Peters-Lidard, C. D.

    2011-12-01

    The declaration of famine in Somalia on July 21, 2011 highlights the need for regional hydroclimate analysis at a scale that is relevant for agropastoral drought monitoring. A particularly critical and robust component of such a drought monitoring system is a land surface model (LSM). We are currently enhancing the Famine Early Warning Systems Network (FEWS NET) monitoring activities by configuring a custom instance of NASA's Land Information System (LIS) called the FEWS NET Land Data Assimilation System (FLDAS). Using the LIS Noah LSM, in-situ measurements, and remotely sensed data, we focus on the following question: How can Noah be best parameterized to accurately simulate hydroclimate variables associated with crop performance? Parameter value testing and validation is done by comparing modeled soil moisture against fortuitously available in-situ soil moisture observations in the West Africa. Direct testing and application of the FLDAS over African agropastoral locations is subject to some issues: [1] In many regions that are vulnerable to food insecurity ground based measurements of precipitation, evapotranspiration and soil moisture are sparse or non-existent, [2] standard landcover classes (e.g., the University of Maryland 5 km dataset), do not include representations of specific agricultural crops with relevant parameter values, and phenologies representing their growth stages from the planting date and [3] physically based land surface models and remote sensing rain data might still need to be calibrated or bias-corrected for the regions of interest. This research aims to address these issues by focusing on sites in the West African countries of Mali, Niger, and Benin where in-situ rainfall and soil moisture measurements are available from the African Monsoon Multidisciplinary Analysis (AMMA). Preliminary results from model experiments over Southern Malawi, validated with Normalized Difference Vegetation Index (NDVI) and maize yield data, show that the

  17. The Foraging Ecology of the Endangered Cape Verde Shearwater, a Sentinel Species for Marine Conservation off West Africa.

    PubMed

    Paiva, Vitor H; Geraldes, Pedro; Rodrigues, Isabel; Melo, Tommy; Melo, José; Ramos, Jaime A

    2015-01-01

    Large Marine Ecosystems such as the Canary Current system off West Africa sustains high abundance of small pelagic prey, which attracts marine predators. Seabirds are top predators often used as biodiversity surrogates and sentinel species of the marine ecosystem health, thus frequently informing marine conservation planning. This study presents the first data on the spatial (GPS-loggers) and trophic (stable isotope analysis) ecology of a tropical seabird-the endangered Cape Verde shearwater Calonectris edwardsii-during both the incubation and the chick-rearing periods of two consecutive years. This information was related with marine environmental predictors (species distribution models), existent areas of conservation concern for seabirds (i.e. marine Important Bird Areas; marine IBAs) and threats to the marine environment in the West African areas heavily used by the shearwaters. There was an apparent inter-annual consistency on the spatial, foraging and trophic ecology of Cape Verde shearwater, but a strong alteration on the foraging strategies of adult breeders among breeding phases (i.e. from incubation to chick-rearing). During incubation, birds mostly targeted a discrete region off West Africa, known by its enhanced productivity profile and thus also highly exploited by international industrial fishery fleets. When chick-rearing, adults exploited the comparatively less productive tropical environment within the islands of Cape Verde, at relatively close distance from their breeding colony. The species enlarged its trophic niche and increased the trophic level of their prey from incubation to chick-rearing, likely to provision their chicks with a more diversified and better quality diet. There was a high overlap between the Cape Verde shearwaters foraging areas with those of European shearwater species that overwinter in this area and known areas of megafauna bycatch off West Africa, but very little overlap with existing Marine Important Bird Areas. Further

  18. The Foraging Ecology of the Endangered Cape Verde Shearwater, a Sentinel Species for Marine Conservation off West Africa

    PubMed Central

    Paiva, Vitor H.; Geraldes, Pedro; Rodrigues, Isabel; Melo, Tommy; Melo, José; Ramos, Jaime A.

    2015-01-01

    Large Marine Ecosystems such as the Canary Current system off West Africa sustains high abundance of small pelagic prey, which attracts marine predators. Seabirds are top predators often used as biodiversity surrogates and sentinel species of the marine ecosystem health, thus frequently informing marine conservation planning. This study presents the first data on the spatial (GPS-loggers) and trophic (stable isotope analysis) ecology of a tropical seabird—the endangered Cape Verde shearwater Calonectris edwardsii–during both the incubation and the chick-rearing periods of two consecutive years. This information was related with marine environmental predictors (species distribution models), existent areas of conservation concern for seabirds (i.e. marine Important Bird Areas; marine IBAs) and threats to the marine environment in the West African areas heavily used by the shearwaters. There was an apparent inter-annual consistency on the spatial, foraging and trophic ecology of Cape Verde shearwater, but a strong alteration on the foraging strategies of adult breeders among breeding phases (i.e. from incubation to chick-rearing). During incubation, birds mostly targeted a discrete region off West Africa, known by its enhanced productivity profile and thus also highly exploited by international industrial fishery fleets. When chick-rearing, adults exploited the comparatively less productive tropical environment within the islands of Cape Verde, at relatively close distance from their breeding colony. The species enlarged its trophic niche and increased the trophic level of their prey from incubation to chick-rearing, likely to provision their chicks with a more diversified and better quality diet. There was a high overlap between the Cape Verde shearwaters foraging areas with those of European shearwater species that overwinter in this area and known areas of megafauna bycatch off West Africa, but very little overlap with existing Marine Important Bird Areas

  19. From Assistance to Partnership: Morocco and Its Foreign Policy in West Africa

    DTIC Science & Technology

    2015-11-01

    contribution of Morocco’s early banking investments. Those charged with the formulation of Moroccan policy and strat- egy towards sub-Saharan Africa have...the Sahel region through initiatives promoting moderate Islam , and concludes with a number of recommendations on how Morocco could be supported by...Sahara issue continues to dominate Morocco’s foreign policy towards African countries and the AU. In June 2014, the appointment of former Mozambican

  20. An updated Bouguer anomaly map of south-central West Africa

    USGS Publications Warehouse

    Hastings, David A.

    1983-01-01

    A new Bouguer gravity anomaly map compiled for western Africa adds data for Ghana, Guinea, and Liberia.The new data add detail to a key part of the Eburnean shield and assist in the development of a model of rifting at the time of the Eburnean orogeny, 2000 million years ago. This model includes a framework for the deposition of the region's mineral deposits. The model and existing field data can be used to guide future minerals exploration in the region.

  1. Decreasing incidence of cryptococcal meningitis in West Africa in the era of highly active antiretroviral therapy.

    PubMed

    Bamba, Sanata; Lortholary, Olivier; Sawadogo, Adrien; Millogo, Athanase; Guiguemdé, Robert T; Bretagne, Stéphane

    2012-05-15

    Cryptococcosis remains a major opportunistic infection in AIDS in sub-Saharan Africa, but few data exist from its western part. We report data from Bobo Dioulasso University Hospital, Bobo-Dioulasso, Burkina Faso, with a steady decline from 14 to two cases per year from 2002 to 2010 which contrasts with the increase (from 147 to 3940) of patients on antiretroviral therapy (ART). Better ART availability decreases the incidence of cryptococcosis in Burkina Faso.

  2. Marine communities on oil platforms in Gabon, West Africa: high biodiversity oases in a low biodiversity environment.

    PubMed

    Friedlander, Alan M; Ballesteros, Enric; Fay, Michael; Sala, Enric

    2014-01-01

    The marine biodiversity of Gabon, West Africa has not been well studied and is largely unknown. Our examination of marine communities associated with oil platforms in Gabon is the first scientific investigation of these structures and highlights the unique ecosystems associated with them. A number of species previously unknown to Gabonese waters were recorded during our surveys on these platforms. Clear distinctions in benthic communities were observed between older, larger platforms in the north and newer platforms to the south or closer to shore. The former were dominated by a solitary cup coral, Tubastraea sp., whereas the latter were dominated by the barnacle Megabalanus tintinnabulum, but with more diverse benthic assemblages compared to the northerly platforms. Previous work documented the presence of limited zooxanthellated scleractinian corals on natural rocky substrate in Gabon but none were recorded on platforms. Total estimated fish biomass on these platforms exceeded one ton at some locations and was dominated by barracuda (Sphyraena spp.), jacks (Carangids), and rainbow runner (Elagatis bipinnulata). Thirty-four percent of fish species observed on these platforms are new records for Gabon and 6% are new to tropical West Africa. Fish assemblages closely associated with platforms had distinct amphi-Atlantic affinities and platforms likely extend the distribution of these species into coastal West Africa. At least one potential invasive species, the snowflake coral (Carijoa riisei), was observed on the platforms. Oil platforms may act as stepping stones, increasing regional biodiversity and production but they may also be vectors for invasive species. Gabon is a world leader in terrestrial conservation with a network of protected areas covering >10% of the country. Oil exploration and biodiversity conservation currently co-exist in terrestrial and freshwater ecosystems in Gabon. Efforts to increase marine protection in Gabon may benefit by including oil

  3. Marine Communities on Oil Platforms in Gabon, West Africa: High Biodiversity Oases in a Low Biodiversity Environment

    PubMed Central

    Friedlander, Alan M.; Ballesteros, Enric; Fay, Michael; Sala, Enric

    2014-01-01

    The marine biodiversity of Gabon, West Africa has not been well studied and is largely unknown. Our examination of marine communities associated with oil platforms in Gabon is the first scientific investigation of these structures and highlights the unique ecosystems associated with them. A number of species previously unknown to Gabonese waters were recorded during our surveys on these platforms. Clear distinctions in benthic communities were observed between older, larger platforms in the north and newer platforms to the south or closer to shore. The former were dominated by a solitary cup coral, Tubastraea sp., whereas the latter were dominated by the barnacle Megabalanus tintinnabulum, but with more diverse benthic assemblages compared to the northerly platforms. Previous work documented the presence of limited zooxanthellated scleractinian corals on natural rocky substrate in Gabon but none were recorded on platforms. Total estimated fish biomass on these platforms exceeded one ton at some locations and was dominated by barracuda (Sphyraena spp.), jacks (Carangids), and rainbow runner (Elagatis bipinnulata). Thirty-four percent of fish species observed on these platforms are new records for Gabon and 6% are new to tropical West Africa. Fish assemblages closely associated with platforms had distinct amphi-Atlantic affinities and platforms likely extend the distribution of these species into coastal West Africa. At least one potential invasive species, the snowflake coral (Carijoa riisei), was observed on the platforms. Oil platforms may act as stepping stones, increasing regional biodiversity and production but they may also be vectors for invasive species. Gabon is a world leader in terrestrial conservation with a network of protected areas covering >10% of the country. Oil exploration and biodiversity conservation currently co-exist in terrestrial and freshwater ecosystems in Gabon. Efforts to increase marine protection in Gabon may benefit by including oil

  4. The 2014 Ebola virus outbreak in West Africa highlights no evidence of rapid evolution or adaptation to humans

    PubMed Central

    Li, Xingguang; Zai, Junjie; Liu, Haizhou; Feng, Yi; Li, Fan; Wei, Jing; Zou, Sen; Yuan, Zhiming; Shao, Yiming

    2016-01-01

    Following its immergence in December 2013, the recent Zaire Ebola virus (EBOV) outbreak in West Africa has spread and persisted for more than two years, making it the largest EBOV epidemic in both scale and geographical region to date. In this study, a total of 726 glycoprotein (GP) gene sequences of the EBOV full-length genome obtained from West Africa from the 2014 outbreak, combined with 30 from earlier outbreaks between 1976 and 2008 were used to investigate the genetic divergence, evolutionary history, population dynamics, and selection pressure of EBOV among distinct epidemic waves. Results from our dataset showed that no non-synonymous substitutions occurred on the GP gene coding sequences of EBOV that were likely to have affected protein structure or function in any way. Furthermore, the significantly different dN/dS ratios observed between the 2014 West African outbreak and earlier outbreaks were more likely due to the confounding presence of segregating polymorphisms. Our results highlight no robust evidence that the 2014 EBOV outbreak is fast-evolving and adapting to humans. Therefore, the unprecedented nature of the 2014 EBOV outbreak might be more likely related to non-virological elements, such as environmental and sociological factors. PMID:27767073

  5. HIV-1 and HIV-2 Infections Among U.S. Peace Corps Volunteers Returning from West Africa.

    PubMed

    Eng; O'Brien; Bernard; Schable; van der Vlugt T; Holmberg

    1995-09-01

    Background: The risk of acquiring HIV-1 and HIV-2 infections among expatriates in, and travelers to, West Africa is not known. The objective of the study was to examine the risk of human immunodeficiency virus type 1 and type 2 (HIV-1 and HIV-2) infections among Peace Corps volunteers in West Africa. Methods: A cross-sectional serosurvey was carried out in 18 West African countries. Subjects were 2491 returning Peace Corps volunteers. The main outcome measure was seropositivity for HIV-1 and HIV-2 antibodies. Results: From March 1988 through February 1993, of 2491 study participants, no HIV-2 infections were detected, but three HIV-1 infections were. All three HIV-1-infected persons reported having had unprotected sex with host-country national partners. Conclusions: Results suggest that although persons having unprotected sex with partners from countries with a high prevalence of HIV-1 are at risk for acquiring the infection, casual transmission of HIV-1 or HIV-2 is extremely unlikely.

  6. Potential climate effect of mineral aerosols over West Africa. Part I: model validation and contemporary climate evaluation

    NASA Astrophysics Data System (ADS)

    Ji, Zhenming; Wang, Guiling; Pal, Jeremy S.; Yu, Miao

    2016-02-01

    Mineral dusts present in the atmosphere can play an important role in climate over West Africa and surrounding regions. However, current understanding regarding how dust aerosols influence climate of West Africa is very limited. In this study, a regional climate model is used to investigate the potential climatic impacts of dust aerosols. Two sets of simulations driven by reanalysis and Earth System Model boundary conditions are performed with and without the representation of dust processes. The model, regardless of the boundary forcing, captures the spatial and temporal variability of the aerosol optical depth and surface concentration. The shortwave radiative forcing of dust is negative at the surface and positive in the atmosphere, with greater changes in the spring and summer. The presence of mineral dusts causes surface cooling and lower troposphere heating, resulting in a stabilization effect and reduction in precipitation in the northern portion of the monsoon close to the dust emissions region. This results in an enhancement of precipitation to the south. While dusts cause the lower troposphere to stabilize, upper tropospheric cooling makes the region more prone to intense deep convection as is evident by a simulated increase in extreme precipitation. In a companion paper, the impacts of dust emissions on future West African climate are investigated.

  7. U.S. Public Health Service Response to the 2014-2015 Ebola Epidemic in West Africa: A Nursing Perspective.

    PubMed

    Mosquera, Alexis; Braun, Michelle; Hulett, Melissa; Ryszka, Lauren

    2015-01-01

    The 2014-2015 Ebola epidemic in West Africa has been the deadliest Ebola epidemic to date. In response to this deadly epidemic, the U.S. government declared this a top national security priority and members of the Commissioned Corps of the United States Public Health Service were tasked to provide direct patient care to Ebola virus disease patients. Commissioned Corps nurses provided the highest level of care under the most austere conditions. This article discusses the training, ethical dilemmas, and constant risk for potential exposure while working in an Ebola Treatment Unit.

  8. Improving Brain Tumor Research in Resource-Limited Countries: A Review of the Literature Focusing on West Africa

    PubMed Central

    Fezeu, Francis; Ramesh, Arjun; Moosa, Shayan; Purow, Benjamin; Lopez, Beatrice; Schiff, David; Hussaini, Isa M; Sandabe, Umar K

    2015-01-01

    Neoplasms of the brain are often overlooked in resource-limited countries. Our literature search via AJOL and PubMed demonstrated that brain tumor research is still a rarity in these regions. We highlight the current status, importance, challenges, and methods of improving brain tumor research in West Africa. We suggest that more attention be given to basic, clinical, and epidemiological brain tumor research by national governments, private organizations, international organizations, non-governmental organizations (NGOs), and individuals in this region. PMID:26677422

  9. Desertification control and renewable-resource management in the Sahelian and Sudanian zones of west africa. Technical paper

    SciTech Connect

    Falloux, F.; Mukendi, A.

    1987-01-01

    This volume is a compendium of papers presented at the 'Workshop on Desertification Control and Renewable Resource Management' held in Oslo, Norway in June 1986, and sponsored by the Norwegian Ministry of Development Cooperation, the Canadian International Development Agency and the World Bank. The main objective of the workshop was to develop workable guidelines for addressing the problem of resource depletion in the Sahelian and Sudanian zones of West Africa. Major policy areas covered include land tenure, water management, household energy use, production systems, and migration.

  10. The Behavior of Gust Fronts in West Africa Based on Radar and Satellite Observations

    NASA Astrophysics Data System (ADS)

    McGraw-Herdeg, M.; Williams, E.

    2009-12-01

    M. McGraw-Herdeg, E. Williams. If we are to understand the global influence of dust storms in the tropical Sahelian region of West Africa, we must first understand what factors affect how these large storms develop, how far they travel, how fast they travel, and how much particulate matter they carry. Observations link the gust fronts of these large, dusty storms to new moist convection. As a first step, we test available theories against measured data by comparing the density current model's predictions of gust front speed (measured at using temperature-drop data measured by the ARM Mobile Facility and speed measurements derived from the MIT C-band radar site, both in Niamey, Niger for the AMMA (African Monsoon and Multidisciplinary Analysis) in 2006. We track intersections of CALIPSO satellite images with the front, as seen by the MIT radar. With speed information for 20 gust fronts tracked by the MIT radar site, we can show how a gust front's speed declines over time as it mixes with its dry environment. By interpreting these data alongside Meteosat satellite dust information (SEVIRI), we describe the average "lifespan" of these gust fronts and their maximum distance of propagation, which may range from 24-36 hours or 1000-1500 km. This analysis contributes precise speed data for a large number of gust fronts measured by the MIT radar. We have measured speeds for 20 gust fronts with 10-minute speeds calculated across a 150-km or 250-km radar circle. The average speed was 14.8 m/s; the average 10-minute speed as the fronts crossed the radar circle was 15.6 m/s. SEVIRI imagery indicates that nearly all the events which crossed the radar site originated at about the same place, and most started within two hours of 15:00, suggesting that local geography and the diurnal cycle plays significant roles in formation of gust fronts. Surface temperature drops as the gust front crosses the radar site were found to be weakly linearly correlated with velocity at crossing

  11. Implications of land use change in tropical West Africa under global warming

    NASA Astrophysics Data System (ADS)

    Brücher, Tim; Claussen, Martin

    2015-04-01

    Northern Africa, and the Sahel in particular, are highly vulnerable to climate change, due to strong exposure to increasing temperature, precipitation variability, and population growth. A major link between climate and humans in this region is land use and associated land cover change, mainly where subsistence farming prevails. But how strongly does climate change affect land use and how strongly does land use feeds back into climate change? To which extent may climate-induced water, food and wood shortages exacerbate conflict potential and lead changes in land use and to migration? Estimates of possible changes in African climate vary among the Earth System Models participating in the recent Coupled Model Intercomparison (CMIP5) exercise, except for the region adjacent to the Mediterranean Sea, where a significant decrease of precipitation emerges. While all models agree in a strong temperature increase, rainfall uncertainties for most parts of the Sahara, Sahel, and Sudan are higher. Here we present results of complementary experiments based on extreme and idealized land use change scenarios within a future climate.. We use the MPI-ESM forced with a strong green house gas scenario (RCP8.5) and apply an additional land use forcing by varying largely the intensity and kind of agricultural practice. By these transient experiments (until 2100) we elaborate the additional impact on climate due to strong land use forcing. However, the differences are mostly insignificant. The greenhouse gas caused temperature increase and the high variability in the West African Monsoon rainfall superposes the minor changes in climate due to land use. While simulated climate key variables like precipitation and temperature are not distinguishable from the CMIP5 RCP8.5 results, an additional greening is simulated, when crops are demanded. Crops have lower water usage than pastureland has. This benefits available soil water, which is taken up by the natural vegetation and makes it more

  12. A new Martian meteorite from Morocco: the nakhlite North West Africa 817

    NASA Astrophysics Data System (ADS)

    Sautter, V.; Barrat, J. A.; Jambon, A.; Lorand, J. P.; Gillet, Ph.; Javoy, M.; Joron, J. L.; Lesourd, M.

    2002-02-01

    North West Africa (NWA 817) is a single stone of 104 g found in the Sahara (Morocco) by meteorite hunters in November 2000. The meteorite is an unbrecciated, medium-grained olivine-bearing clinopyroxenite with a cumulate texture. It consists of zoned euhedral subcalcic augite (Wo 42En 38-22Fs 20-36), olivine spanning a wide range of compositions (from Fa 56 in the core to Fa 86) with rare magmatic inclusions and an intercumulus mesostasis made of Fe-bearing albitic plagioclase, Si-rich glass, Ti-magnetite with unusual skeletal growth morphologies containing ilmenite exsolutions, acicular pyroxene, olivine and cristobalite. Trace minerals are sulfide droplets and Cl-apatite. Mineral modes (in vol%) are augite 69%, olivine 10%, mesostasis 20% and Fe-Ti oxides 1%. Pervasive alteration produced a reddish clay mineral (hydrous ferrous silicate) in both olivine crystals and the mesostasis. The major element composition of NWA 817 is very similar to that of the other nakhlites: high FeO, MgO and CaO concentrations reflect the abundance of cumulus augite and olivine. Key element ratios such as FeO/MnO (=37), Na/Al (=0.40), K/La (=449), Ga/Al (=3.9×10 -4) and oxygen isotopic composition (Δ 17O=+0.37‰) are clear evidence for a Martian origin. The incompatible trace element pattern as in Nakhla displays a strong light rare earth element enrichment relative to chondrite (La n/Yb n=4.89). However, when compared to the other nakhlites, NWA 817 has specific features: (1) a higher modal proportion of mesostasis; (2) quench textures of Ti-magnetite and Fe-rich clinopyroxene; (3) more Mg-rich olivine core compositions whereas the augite core composition is identical for all nakhlites; (4) a stronger Fe enrichment toward crystal rims of these cumulus minerals. The intercumulus minerals (Ti-magnetite with skeletal growth morphology, acicular chains of clinopyroxene and Fe 3+-rich feldspar) indicate rapid crystallization in response to a high degree of undercooling at the end of

  13. Oral lesions among HIV-infected children on antiretroviral treatment in West Africa

    PubMed Central

    Meless, David; Ba, Boubacar; Faye, Malick; Diby, Jean-Serge; N’zoré, Serge; Datté, Sébastien; Diecket, Lucrèce; N’Diaye, Clémentine; Aka, Edmond Addi; Kouakou, Kouadio; Ba, Abou; Ekouévi, Didier Koumavi; Dabis, François; Shiboski, Caroline; Arrivé, Elise

    2014-01-01

    Objectives To estimate the prevalence of oral mucosal diseases and dental caries among HIV-infected children receiving antiretroviral treatment (ART) in West Africa, and to identify factors associated with the prevalence of oral mucosal lesions. Methods Multi-center cross-sectional survey in 5 pediatric HIV clinics in Côte d’Ivoire, Mali and Sénégal. A standardized examination was performed by trained dentists on a random sample of HIV-infected children aged 5 to 15 years receiving ART. The prevalence of oral and dental lesions and mean number of decayed, missing/extracted and filled teeth (DMFdefT) in temporary and permanent dentition were estimated with their 95% confidence interval (95%CI). We used logistic regression to explore the association between children’s characteristics and the prevalence of oral mucosal lesions, expressed as prevalence odds ratio (POR). Results The median age of the 420 children (47% females) enrolled was 10.4 years (interquartile range [IQR]=8.3–12.6). The median duration on ART was 4.6 years (IQR=2.6–6.2); 84 (20.0%) had CD4 count<350 cells/mm3. 35 children (8.3%; 95%CI: [6.1–11.1]) exhibited 42 oral mucosal lesions (24 were candidiasis); 86.0% (95%CI=82.6–89.3) of children had DMFdefT≥1. The presence of oral mucosal lesions was independently associated with CD4 count<350 cells/mm3 (POR=2.96, 95% CI=1.06–4.36) and poor oral hygiene (POR=2.69, 95%CI=1.07–6.76). Conclusions Oral mucosal lesions still occur in HIV-infected African children despite ART, but rarely. However, dental caries were common and severe in this population, reflecting the need to include oral health in the comprehensive care of HIV. PMID:24386972

  14. The Sahel Region of West Africa: Examples of Climate Analyses Motivated By Drought Management Needs

    NASA Astrophysics Data System (ADS)

    Ndiaye, O.; Ward, M. N.; Siebert, A. B.

    2011-12-01

    The Sahel is one of the most drought-prone regions in the world. This paper focuses on climate sources of drought, and some new analyses mostly driven by users needing climate information to help in drought management strategies. The Sahel region of West Africa is a transition zone between equatorial climate and vegetation to the south, and desert to the north. The climatology of the region is dominated by dry conditions for most of the year, with a single peak in rainfall during boreal summer. The seasonal rainfall total contains both interannual variability and substantial decadal to multidecadal variability (MDV). This brings climate analysis and drought management challenges across this range of timescales. The decline in rainfall from the wet decades of the 1950s and 60s to the dry decades of the 1970s and 80s has been well documented. In recent years, a moderate recovery has emerged, with seasonal totals in the period 1994-2010 significantly higher than the average rainfall 1970-1993. These MDV rainfall fluctuations have expression in large-scale sea-surface temperature fluctuations in all ocean basins, placing the changes in drought frequency within broader ocean-atmosphere climate fluctuation. We have evaluated the changing character of low seasonal rainfall total event frequencies in the Sahel region 1950-2010, highlighting the role of changes in the mean, variance and distribution shape of seasonal rainfall totals as the climate has shifted through the three observed phases. We also consider the extent to which updating climate normals in real-time can damp the bias in expected event frequency, an important issue for the feasibility of index insurance as a drought management tool in the presence of a changing climate. On the interannual timescale, a key factor long discussed for agriculture is the character of rainfall onset. An extended dry spell often occurs early in the rainy season before the crop is fully established, and this often leads to crop

  15. Geostatistical Model-Based Estimates of Schistosomiasis Prevalence among Individuals Aged ≤20 Years in West Africa

    PubMed Central

    Schur, Nadine; Hürlimann, Eveline; Garba, Amadou; Traoré, Mamadou S.; Ndir, Omar; Ratard, Raoult C.; Tchuem Tchuenté, Louis-Albert; Kristensen, Thomas K.; Utzinger, Jürg; Vounatsou, Penelope

    2011-01-01

    Background Schistosomiasis is a water-based disease that is believed to affect over 200 million people with an estimated 97% of the infections concentrated in Africa. However, these statistics are largely based on population re-adjusted data originally published by Utroska and colleagues more than 20 years ago. Hence, these estimates are outdated due to large-scale preventive chemotherapy programs, improved sanitation, water resources development and management, among other reasons. For planning, coordination, and evaluation of control activities, it is essential to possess reliable schistosomiasis prevalence maps. Methodology We analyzed survey data compiled on a newly established open-access global neglected tropical diseases database (i) to create smooth empirical prevalence maps for Schistosoma mansoni and S. haematobium for individuals aged ≤20 years in West Africa, including Cameroon, and (ii) to derive country-specific prevalence estimates. We used Bayesian geostatistical models based on environmental predictors to take into account potential clustering due to common spatially structured exposures. Prediction at unobserved locations was facilitated by joint kriging. Principal Findings Our models revealed that 50.8 million individuals aged ≤20 years in West Africa are infected with either S. mansoni, or S. haematobium, or both species concurrently. The country prevalence estimates ranged between 0.5% (The Gambia) and 37.1% (Liberia) for S. mansoni, and between 17.6% (The Gambia) and 51.6% (Sierra Leone) for S. haematobium. We observed that the combined prevalence for both schistosome species is two-fold lower in Gambia than previously reported, while we found an almost two-fold higher estimate for Liberia (58.3%) than reported before (30.0%). Our predictions are likely to overestimate overall country prevalence, since modeling was based on children and adolescents up to the age of 20 years who are at highest risk of infection. Conclusion/Significance We

  16. Exposure Patterns Driving Ebola Transmission in West Africa: A Retrospective Observational Study

    PubMed Central

    Agua-Agum, Junerlyn; Aylward, Bruce; Bawo, Luke; Blake, Isobel M.; Brennan, Richard J.; Cawthorne, Amy; Cleary, Eilish; Clement, Peter; Conteh, Roland; Cori, Anne; Dafae, Foday; Dahl, Benjamin; Dangou, Jean-Marie; Diallo, Boubacar; Donnelly, Christl A.; Dye, Christopher; Eckmanns, Tim; Fallah, Mosoka; Fiebig, Lena; Fraser, Christophe; Garske, Tini; Gonzalez, Lice; Hamblion, Esther; Hamid, Nuha; Hinsley, Wes; Jambei, Amara; Jombart, Thibaut; Kargbo, David; Keita, Sakoba; Kinzer, Michael; George, Fred Kuti; Godefroy, Beatrice; Gutierrez, Giovanna; Kannangarage, Niluka; Mills, Harriet L.; Moller, Thomas; Meijers, Sascha; Mohamed, Yasmine; Newton, Emily; Nouvellet, Pierre; Nyenswah, Tolbert; Perea, William; Perkins, Devin; Riley, Steven; Rondy, Marc; Sagrado, Maria; Savulescu, Camelia; Schafer, Ilana J.; Schumacher, Dirk; Seyler, Thomas; Shah, Anita; Van Kerkhove, Maria D.; Wesseh, C. Samford; Yoti, Zabulon

    2016-01-01

    Background The ongoing West African Ebola epidemic began in December 2013 in Guinea, probably from a single zoonotic introduction. As a result of ineffective initial control efforts, an Ebola outbreak of unprecedented scale emerged. As of 4 May 2015, it had resulted in more than 19,000 probable and confirmed Ebola cases, mainly in Guinea (3,529), Liberia (5,343), and Sierra Leone (10,746). Here, we present analyses of data collected during the outbreak identifying drivers of transmission and highlighting areas where control could be improved. Methods and Findings Over 19,000 confirmed and probable Ebola cases were reported in West Africa by 4 May 2015. Individuals with confirmed or probable Ebola (“cases”) were asked if they had exposure to other potential Ebola cases (“potential source contacts”) in a funeral or non-funeral context prior to becoming ill. We performed retrospective analyses of a case line-list, collated from national databases of case investigation forms that have been reported to WHO. These analyses were initially performed to assist WHO’s response during the epidemic, and have been updated for publication. We analysed data from 3,529 cases in Guinea, 5,343 in Liberia, and 10,746 in Sierra Leone; exposures were reported by 33% of cases. The proportion of cases reporting a funeral exposure decreased over time. We found a positive correlation (r = 0.35, p < 0.001) between this proportion in a given district for a given month and the within-district transmission intensity, quantified by the estimated reproduction number (R). We also found a negative correlation (r = −0.37, p < 0.001) between R and the district proportion of hospitalised cases admitted within ≤4 days of symptom onset. These two proportions were not correlated, suggesting that reduced funeral attendance and faster hospitalisation independently influenced local transmission intensity. We were able to identify 14% of potential source contacts as cases in the case line

  17. Hydro-gravimetry in West-Africa: First results from the Djougou (Benin) superconducting gravimeter

    NASA Astrophysics Data System (ADS)

    Hector, Basile; Hinderer, Jacques; Séguis, Luc; Boy, Jean-Paul; Calvo, Marta; Descloitres, Marc; Rosat, Séverine; Galle, Sylvie; Riccardi, Umberto

    2014-10-01

    The increasing number of hydro-gravimetry studies proves the rising interest of the hydrology community toward this monitoring method. The accuracy of superconducting gravimeters (SG) potentially allows the retrieval of small water storage changes (WSC) down to a few millimeters of equivalent water thickness. However, the importance of corrections applied to SG data to achieve such a precision in gravity residuals should be recalled. The Djougou permanent gravity station presented in this paper and located in northern Benin, West-Africa, provides a good opportunity to review these considerations. This station is equipped since July 2010 with the superconducting gravimeter SG-060 aimed at deriving WSC at different time-scales, daily to inter-annual. In this area, WSC are (1) part of the control system for evapotranspiration (ET) process, a key variable of the West-African monsoon cycle and (2) the state variable for resource management, a critical issue in storage-poor hard rock basement contexts such as in northern Benin. The potential for deriving WSC from time-lapse gravity data partly depends on environmental features such as topography and the instrument shelter. Therefore, this issue is addressed first, with the background idea that such sensitivity analysis should be undertaken before setting up any new instrument. In Djougou, local topography is quite flat leading to a theoretical straightforward relationship between gravity changes and WSC, close to the standard Bouguer value. However, the shelter plays a significant masking role, which is the principal limitation to the retrieval of fast hydrological processes such as ET following a rain event. Several issues concerning classical gravity corrections are also addressed in the paper. These include gap-filling procedures during rain-events and drift estimates for short time series. Special attention is provided to atmospheric corrections, and different approaches are tested: a simple scalar admittance, a

  18. Evaluating climate change impacts and adaptation options for agriculture in West Africa: a multi-model comparison

    NASA Astrophysics Data System (ADS)

    Sultan, B.; Lobell, D. B.; Biasutti, M.; Guan, K.; Roudier, P.; Piani, C.

    2013-12-01

    Climate change is likely to stress food production in many parts of the developing world over the next few decades. In areas such as West Africa, where poor communities are highly dependent on the direct use of local natural resources, the effects of climate change on food security could be particularly devastating. Given these concerns, there is great interest in identifying and investing in technologies or practices that could help farmers adapt to climate variability and change. Recent studies found a robust agreement across the various climate models of the IPCC Coupled Models Inter-comparison Program ensemble on the seasonal distribution of Sahel rainfall changes (with a drying of the early season and positive rainfall anomaly at the end) in contrast with a large uncertainty for summertime rainfall totals. These changes will therefore certainly impact agriculture strategy (selection of new cultivars, later sowing) and output. This study estimates such impacts by using a series of climate scenarios as input for two crop models for multiple locations within West Africa. Simulations are run for the two major crops in the region - sorghum and millets. Building on the above simulations, we then simulate different scenarios of adaptation that could be used to cope with climate changes.

  19. Assessment of Regional Climate Models over Côte d'Ivoire and Analysis of Future Projections over West Africa

    NASA Astrophysics Data System (ADS)

    Kouadio, K.; Konare, A.; Diawara, A.; Dje, B. K.; Ajayi, V. O.; Diedhiou, A.

    2015-12-01

    The ability of six Regional Climate Models (RCMs) used in AMMA-ENSEMBLES project is assessed over six meteorological stations in Côte d'Ivoire. The ensemble mean of the models is also used for the prediction of climate change over West Africa. The study focused on two periods: the period 1995-2005, the present-day simulations, is used to evaluate the skills of the models over the country and the years 2010-2013, for assessment of the future climate change scenario used. The results show that the skills of the models vary from one station to another and from one season to another. None of the models considered, presents an excellent performance over the entire country and in all the seasons. Generally, the ensemble mean of all the models presents better results when compared with the observation. These results suggest that the choice of any model for study over the country may depend on the focus of interest: intensity or variability of the rain and also on area of interest. The projection for 2020-2040, future climate change over West Africa shows that the Sahel exhibits a tendency to be drier while wetter Guinean coast is observed

  20. The monetary value of human milk in Francophone west Africa: a PROFILES analysis for nutrition policy communication.

    PubMed

    Aguayo, Víctor M; Ross, Jay

    2002-06-01

    Using a simple and conservative methodology, we estimated the volume and monetary value of the human milk produced by lactating women in Francophone West Africa. In that region, children zero to 35.9 months old consume over 1.1 billion liters of human milk per year. However, suboptimal breastfeeding practices account for the loss of 175 million liters of human milk annually. If the human milk consumed by children zero to 35.9 months old were to be adequately replaced using commercial breastmilk substitutes, an annual expenditure of about 2 billion US dollars would be needed. At the household level, the annual replacement cost of human milk would amount to US$412 per infant. This is beyond the reach of most families in West Africa, where as many as 61% of families in some countries live on less than one US dollar per day. Appropriate policies to foster breastfeeding need to be developed and adequately implemented. Such policy action is more likely to occur if decision makers fully appreciate the monetary value of human milk.

  1. Changes in Intense Precipitation Events in West Africa and the central U.S. under Global Warming

    SciTech Connect

    Cook, Kerry H.; Vizy, Edward

    2016-02-08

    The purpose of the proposed project is to improve our understanding of the physical processes and large-scale connectivity of changes in intense precipitation events (high rainfall rates) under global warming in West Africa and the central U.S., including relationships with low-frequency modes of variability. This is in response to the requested subject area #2 “simulation of climate extremes under a changing climate … to better quantify the frequency, duration, and intensity of extreme events under climate change and elucidate the role of low frequency climate variability in modulating extremes.” We will use a regional climate model and emphasize an understanding of the physical processes that lead to an intensification of rainfall. The project objectives are as follows: 1. Understand the processes responsible for simulated changes in warm-season rainfall intensity and frequency over West Africa and the Central U.S. associated with greenhouse gas-induced global warming 2. Understand the relationship between changes in warm-season rainfall intensity and frequency, which generally occur on regional space scales, and the larger-scale global warming signal by considering modifications of low-frequency modes of variability. 3. Relate changes simulated on regional space scales to global-scale theories of how and why atmospheric moisture levels and rainfall should change as climate warms.

  2. Simulating and Tracking a Heavily Rainy Wave over West Africa Using a Modeling Strategy with WRF Model

    NASA Astrophysics Data System (ADS)

    Sarr, A.

    2014-12-01

    The last decades, over Sahel, are characterized by a relative recovery in rainfall compared to the long drought, which affected this part of West Africa in the 70s, 80s and early 90s. It is also noted an increase of extreme events, mainly excess of rainfall causing damages to many parts of the Sahel area. In this study, we are focusing on an extreme case, which occurred during September 2009. A deep African Easterly Wave (AEW) crossed the region from Niger to Senegal giving heavy rains along its path with a maximum of more than 260mm in Ouagadougou, Burkina Faso. While continuing its trajectory other strong winds associated with the systems caused other kind of damages. A modeling strategy, based on a moving nest with the Weather Research and Forecast model (WRF-ARW), is used to simulate the system. The model is run at 27 and 9km respectively for the outer and inner domains. Key parameters are investigated in order to assess the ability of WRF model in simulating the even. The study has shown good performance of WRF in simulating tropical systems. Noted weaknesses are also highlighted in the study, which showed promising results in simulating extremes, hours to days head, in support to early warning systems (EWS) to mitigate the adverse effects of extremes. This is a key responsibility of National Meteorological Services lacking this capacity in developing countries of West Africa.

  3. Solar drying of mangoes: preservation of an important source of vitamin A in French-speaking West Africa.

    PubMed

    Rankins, Jenice; Sathe, Shridhar K; Spicer, Maria T

    2008-06-01

    Vitamin A deficiency, which is especially widespread among children younger than age 5 years, is a major barrier to reducing child mortality rates in French-speaking West Africa. A large amount of an indigenous plant source of provitamin A carotenoids are lost to postharvest waste. For example, the postharvest loss of mangoes in the region exceeds an annual total of 100,000 metric tons. In our study, 3.75 metric tons of fresh mangoes were dried using a solar dryer to a final moisture content of 10% to 12%, yielding a total of 360 kg dried mango. The product analysis revealed 4,000+/-500 microg beta carotene/100 g and 3,680+/-150 microg beta carotene/100 g after 2 and 6 months of storage, respectively. Thus, one greenhouse solar dryer is capable of reducing postharvest mango waste by 3.75 tons providing up to 1.15 million retinol activity equivalents of dietary vitamin A. The use of this technology that requires solar energy and manpower has the potential of increasing dietary vitamin A supply by up to 27,000-fold, compared to the currently available vitamin A in the region. Moreover, mango is a fruit that is well-liked by the population in this geographic area increasing the likelihood of its ready acceptance. Reducing postharvest loss of mangoes by using greenhouse model solar dryers is a promising strategy to help combat vitamin A deficiency in French-speaking West Africa.

  4. Characteristics of HIV-2 and HIV-1/HIV-2 Dually Seropositive Adults in West Africa Presenting for Care and Antiretroviral Therapy: The IeDEA-West Africa HIV-2 Cohort Study

    PubMed Central

    Ekouevi, Didier K.; Balestre, Eric; Coffie, Patrick A.; Minta, Daouda; Messou, Eugene; Sawadogo, Adrien; Minga, Albert; Sow, Papa Salif; Bissagnene, Emmanuel; Eholie, Serge P.; Gottlieb, Geoffrey S.; Dabis, François; Zannou, Djimon Marcel; Ahouada, Carin; Akakpo, Jocelyn; Ahomadegbé, Christelle; Bashi, Jules; Gougounon-Houéto, Alice; Azon-Kouanou, Angèle; Houngbé, Fabien; Koumakpaï, Sikiratou; Alihonou, Florence; d’Almeida, Marcelline; Hodonou, Irvine; Hounhoui, Ghislaine; Sagbo, Gracien; Tossa-Bagnan, Leïla; Adjide, Herman; Drabo, Joseph; Bognounou, René; Dienderé, Arnaud; Traore, Eliezer; Zoungrana, Lassane; Zerbo, Béatrice; Sawadogo, Adrien Bruno; Zoungrana, Jacques; Héma, Arsène; Soré, Ibrahim; Bado, Guillaume; Tapsoba, Achille; Yé, Diarra; Kouéta, Fla; Ouedraogo, Sylvie; Ouédraogo, Rasmata; Hiembo, William; Gansonré, Mady; Messou, Eugène; Gnokoro, Joachim Charles; Koné, Mamadou; Kouakou, Guillaume Martial; Bosse, Clarisse Amani; Brou, Kouakou; Assi, Achi Isidore; Chenal, Henri; Hawerlander, Denise; Soppi, Franck; Minga, Albert; Abo, Yao; Bomisso, Germain; Eholié, Serge Paul; Amego, Mensah Deborah Noelly; Andavi, Viviane; Diallo, Zelica; Ello, Frédéric; Tanon, Aristophane Koffi; Koule, Serge Olivier; Anzan, Koffi Charles; Guehi, Calixte; Aka, Edmond Addi; Issouf, Koffi Ladji; Kouakou, Jean-Claude; N’Gbeche, Marie-Sylvie; Touré, Pety; Avit-Edi, Divine; Kouakou, Kouadio; Moh, Magloire; Yao, Valérie Andoblé; Folquet, Madeleine Amorissani; Dainguy, Marie-Evelyne; Kouakou, Cyrille; Méa-Assande, Véronique Tanoh; Oka-Berete, Gladys; Zobo, Nathalie; Acquah, Patrick; Kokora, Marie-Berthe; Eboua, Tanoh François; Timité-Konan, Marguerite; Ahoussou, Lucrèce Diecket; Assouan, Julie Kebé; Sami, Mabéa Flora; Kouadio, Clémence; Renner, Lorna; Goka, Bamenla; Welbeck, Jennifer; Sackey, Adziri; Owiafe, Seth Ntiri; Wejse, Christian; Silva, Zacarias José Da; Paulo, Joao; Rodrigues, Amabelia; da Silva, David; Medina, Candida; Oliviera-Souto, Ines; Østergaard, Lars; Laursen, Alex; Sodemann, Morten; Aaby, Peter; Fomsgaard, Anders; Erikstrup, Christian; Eugen-Olsen, Jesper; Maïga, Moussa Y; Diakité, Fatoumata Fofana; Kalle, Abdoulaye; Katile, Drissa; Traore, Hamar Alassane; Minta, Daouda; Cissé, Tidiani; Dembelé, Mamadou; Doumbia, Mohammed; Fomba, Mahamadou; Kaya, Assétou Soukho; Traoré, Abdoulaye M; Traoré, Hamady; Toure, Amadou Abathina; Dicko, Fatoumata; Sylla, Mariam; Berthé, Alima; Traoré, Hadizatou Coulibaly; Koïta, Anta; Koné, Niaboula; N'Diaye, Clémentine; Coulibaly, Safiatou Touré; Traoré, Mamadou; Traoré, Naïchata; Charurat, Man; Ajayi, Samuel; Dapiap, Stephen; Otu; Igbinoba, Festus; Benson, Okwara; Adebamowo, Clément; James, Jesse; Obaseki; Osakede, Philip; Olasode, John; Sow, Papa Salif; Diop, Bernard; Manga, Noël Magloire; Tine, Judicael Malick; Signate Sy, Haby; Ba, Abou; Diagne, Aida; Dior, Hélène; Faye, Malick; Gueye, Ramatoulaye Diagne; Mbaye, Aminata Diack; Patassi, Akessiwe; Kotosso, Awèrou; Kariyare, Benjamin Goilibe; Gbadamassi, Gafarou; Komi, Agbo; Mensah-Zukong, Kankoé Edem; Pakpame, Pinuwe; Lawson-Evi, Annette Koko; Atakouma, Yawo; Takassi, Elom; Djeha, Améyo; Ephoévi-gah, Ayoko; Djibril, Sherifa El-Hadj; Dabis, François; Bissagnene, Emmanuel; Arrivé, Elise; Coffie, Patrick; Ekouevi, Didier; Jaquet, Antoine; Leroy, Valériane; Lewden, Charlotte; Sasco, Annie; Azani, Jean-Claude; Allou, Gérard; Balestre, Eric; Bohossou, Franck; Karcher, Sophie; Gonsan, Jules Mahan; Carrou, Jérôme Le; Lenaud, Séverin; Nchot, Célestin; Malateste, Karen; Yao, Amon Roseamonde; Siloué, Bertine; Clouet, Gwenaelle; Djetouan, Hugues; Doring, Alexandra; Kouakou, Adrienne; Rabourdin, Elodie; Rivenc, Jean; Anglaret, Xavier; Ba, Boubacar; Essanin, Jean Bosco; Ciaranello, Andrea; Datté, Sébastien; Desmonde, Sophie; Diby, Jean-Serge Elvis; Gottlieb, Geoffrey S.; Horo, Apollinaire Gninlgninrin; Kangah, Serge N'zoré; Malvy, Denis; Meless, David; Mounkaila-Harouna, Aida; Ndondoki, Camille; Shiboski, Caroline; Thiébaut, Rodolphe; PAC-CI; Abidjan

    2013-01-01

    Background HIV-2 is endemic in West Africa. There is a lack of evidence-based guidelines on the diagnosis, management and antiretroviral therapy (ART) for HIV-2 or HIV-1/HIV-2 dual infections. Because of these issues, we designed a West African collaborative cohort for HIV-2 infection within the framework of the International epidemiological Databases to Evaluate AIDS (IeDEA). Methods We collected data on all HIV-2 and HIV-1/HIV-2 dually seropositive patients (both ARV-naive and starting ART) and followed-up in clinical centres in the IeDEA-WA network including a total of 13 clinics in five countries: Benin, Burkina-Faso Côte d’Ivoire, Mali, and Senegal, in the West Africa region. Results Data was merged for 1,754 patients (56% female), including 1,021 HIV-2 infected patients (551 on ART) and 733 dually seropositive for both HIV-1 and HIV 2 (463 on ART). At ART initiation, the median age of HIV-2 patients was 45.3 years, IQR: (38.3–51.7) and 42.4 years, IQR (37.0–47.3) for dually seropositive patients (p = 0.048). Overall, 16.7% of HIV-2 patients on ART had an advanced clinical stage (WHO IV or CDC-C). The median CD4 count at the ART initiation is 166 cells/mm3, IQR (83–247) among HIV-2 infected patients and 146 cells/mm3, IQR (55–249) among dually seropositive patients. Overall, in ART-treated patients, the CD4 count increased 126 cells/mm3 after 24 months on ART for HIV-2 patients and 169 cells/mm3 for dually seropositive patients. Of 551 HIV-2 patients on ART, 5.8% died and 10.2% were lost to follow-up during the median time on ART of 2.4 years, IQR (0.7–4.3). Conclusions This large multi-country study of HIV-2 and HIV-1/HIV-2 dual infection in West Africa suggests that routine clinical care is less than optimal and that management and treatment of HIV-2 could be further informed by ongoing studies and randomized clinical trials in this population. PMID:23824279

  5. Generation 2030/Africa

    ERIC Educational Resources Information Center

    You, Danzhen; Hug, Lucia; Anthony, David

    2014-01-01

    Until relatively recently, much of Africa has been among the economically least developed and least densely populated places on earth, replete with villages and rural communities. Africa is changing rapidly, in its economy, trade and investment; in climate change; in conflict and stability; in urbanization, migration patterns, and most of all in…

  6. Language in South Africa.

    ERIC Educational Resources Information Center

    Mesthrie, Rajend, Ed.

    This collection of 24 papers focuses on language and society in South Africa. Part 1, "The Main Language Groupings," includes (1) "South Africa: A Sociolinguistic Overview" (R. Mesthrie); (2) "The Khoesan Languages" (A. Traill); (3) "The Bantu Languages: Sociohistorical Perspectives" (Robert K. Herbert and…

  7. Teaching about Francophone Africa.

    ERIC Educational Resources Information Center

    Merryfield, Mary; Timbo, Adama

    Lessons and resources for Social Studies and French courses are included in this document. The major goals of these materials are to help students (1) explore the history and geography of Francophone Africa, (2) examine French influences in contemporary Africa, (3) recognize and appreciate cultural differences and similarities in values and…

  8. Trends in health surveillance and joint service delivery for pastoralists in West and Central Africa.

    PubMed

    Abakar, M F; Schelling, E; Béchir, M; Ngandolo, B N; Pfister, K; Alfaroukh, I O; Hassane, H M; Zinsstag, J

    2016-11-01

    In most sub-Saharan African countries, pastoralism represents an important economic resource and contributes significantly to national growth; however, challenges remain, particularly in providing social services to pastoralists (especially health and education) and in avoiding conflict with local sedentary communities and local authorities. All of this takes place while pastoralists try to maintain their mobile lifestyle within a rapidly changing ecosystem. Transdisciplinary approaches, such as 'One Health', which covers both human and animal health, have proven effective in delivering services and reaching mobile pastoralists in remote areas. The pastoralist way of life could be described as being linked to both their livestock and their environment, which makes social science an important element when researching the delivery and adaptation of social services to pastoralists. Early or pre-diagnostic detection of emerging and endemic infectious disease remains a vital aspect of health surveillance targeted at preventing further transmission and spread. Community-based syndromic surveillance, coupled with visual mobile phone technology, adapted to the high levels of illiteracy among nomads, could offer an alternative to existing health surveillance systems. Such an approach could contribute to accelerated reporting, which could in turn lead to targeted intervention among mobile pastoralists in sub-Saharan Africa. Although considerable efforts have been made towards integrating mobile pastoralists into social services, obstacles remain to the adoption of a clear, specific and sustainable policy on pastoralism in sub-Saharan Africa.

  9. The UNEP Shelf Programme: Highlighting efforts in West Africa and the Pacific Islands

    NASA Astrophysics Data System (ADS)

    Baker, E.; Beaudoin, Y. C.; Brekke, H.; Fabres, J.; Halvorsen, O.; Harris, P. T.; Lonne, O.; Nilsen, R.; Sorensen, M.; Thygesen, K.

    2013-12-01

    The UNEP Shelf Programme, coordinated by GRID-Arendal (a center collaborating with UNEP) was established in 2003 in response to Article 76 of the UN Convention on the Law of the Sea (UNCLOS) and UN General Assembly resolution 57/141. The Programme provides scientific and technical support to developing countries to assist in making timely submissions under the Convention to establish the outer limits of their continental shelf. The deadline for most states was midnight on 12 May 2009. All states that were expected to submit, managed to meet the deadline, and almost all developing states received support from the UNEP Shelf Programme. The support ranged from comprehensive capacity building and tailor-made training, to access to data from GRID-Arendal's One Stop Data Shop (OSDS). Two case studies will be presented and discussed: In the period from 8 December 2011 to 20 June 2012, the ship 'Sea Surveyor' of Gardline Hydro carried out a regional marine acquisition program off West Africa. The acquisition program was part of a joint project between seven African states (Mauretania, Senegal, the Gambia, Cape Verde, Guinea Bissau, Guinea and Sierra Leone) in cooperation with the Government of Norway. The data were acquired for the purpose of delineating and documenting the outer limits of the continental shelf of the seven states in accordance with article 76 of UNCLOS. Multibeam bathymetry (40 000 km) was acquired for the identification of the base of slope (BOS) and for the detailed foot of slope (FOS) analyses. Single channel reflection seismic (36 000 km) and sub bottom profiler data (40 000 km) were acquired for the interpretation of the general geology (including basement characteristics and sediment thickness) and recent sedimentary processes, respectively, as supportive evidence in the establishment of the BOS. In two areas, multi channel reflection seismic (4 000 km) data were acquired for the purpose of detailed sediment thickness analyses. Wide-angle reflection

  10. The Use of Lactic Acid Bacteria Starter Cultures during the Processing of Fermented Cereal-based Foods in West Africa: A Review

    PubMed Central

    Soro-Yao, Amenan Anastasie; Brou, Kouakou; Amani, Georges; Thonart, Philippe; Djè, Koffi Marcelin

    2014-01-01

    Lactic acid bacteria (LAB) are the primary microorganisms used to ferment maize-, sorghum- or millet-based foods that are processed in West Africa. Fermentation contributes to desirable changes in taste, flavour, acidity, digestibility and texture in gruels (ogi, baca, dalaki), doughs (agidi, banku, komé) or steam-cooked granulated products (arraw, ciacry, dégué). Similar to other fermented cereal foods that are available in Africa, these products suffer from inconsistent quality. The use of LAB starter cultures during cereal dough fermentation is a subject of increasing interest in efforts to standardise this step and guaranty product uniformity. However, their use by small-scale processing units or small agro-food industrial enterprises is still limited. This review aims to illustrate and discuss major issues that influence the use of LAB starter cultures during the processing of fermented cereal foods in West Africa. PMID:27073601

  11. Phylogenetic and pathotypic characterization of newcastle disease viruses circulating in west Africa and efficacy of a current vaccine.

    PubMed

    Samuel, Arthur; Nayak, Baibaswata; Paldurai, Anandan; Xiao, Sa; Aplogan, Gilbert L; Awoume, Kodzo A; Webby, Richard J; Ducatez, Mariette F; Collins, Peter L; Samal, Siba K

    2013-03-01

    Newcastle disease (ND) is a deadly avian disease worldwide. In Africa, ND is enzootic and causes large economic losses, but little is known about the Newcastle disease virus (NDV) strains circulating in African countries. In this study, 27 NDV isolates collected from apparently healthy chickens in live-bird markets of the West African countries Benin and Togo in 2009 were characterized. All isolates had polybasic fusion (F)-protein cleavage sites and were shown to be highly virulent in standard pathogenicity assays. Infection of 2-week-old chickens with two of the isolates resulted in 100% mortality within 4 days. Phylogenetic analysis of the 27 isolates based on a partial F-protein gene sequence identified three clusters: one containing all the isolates from Togo and one from Benin (cluster 2), one containing most isolates from Benin (cluster 3), and an outlier isolate from Benin (cluster 1). All the three clusters are related to genotype VII strains of NDV. In addition, the cluster of viruses from Togo contained a recently identified 6-nucleotide insert between the hemagglutinin-neuraminidase (HN) and large polymerase (L) genes in a complete genome of an NDV isolate from this geographical region. Multiple strains that include this novel element suggest local emergence of a new genome length class. These results reveal genetic diversity within and among local NDV populations in Africa. Sequence analysis showed that the F and HN proteins of six West African isolates share 83.2 to 86.6% and 86.5 to 87.9% identities, respectively, with vaccine strain LaSota, indicative of considerable diversity. A vaccine efficacy study showed that the LaSota vaccine protected birds from morbidity and mortality but did not prevent shedding of West African challenge viruses.

  12. Roles and interactions of begomoviruses and satellite DNAs associated with okra leaf curl disease in Mali, West Africa.

    PubMed

    Kon, Tatsuya; Rojas, Maria R; Abdourhamane, Issoufou K; Gilbertson, Robert L

    2009-04-01

    Okra leaf curl disease (OLCD) is a major constraint on okra (Abelmoschus esculentus) production in West Africa. Two monopartite begomoviruses (okra virus-1 and okra virus-2), a betasatellite and a DNA1 satellite are associated with OLCD in Mali. Okra virus-1 is an isolate of okra yellow crinkle virus (OYCrV), okra virus-2 is a recombinant isolate of cotton leaf curl Gezira virus (CLCuGV) and the betasatellite is a variant of cotton leaf curl Gezira betasatellite (CLCuGB). Cloned DNA of OYCrV and CLCuGV were infectious and induced leaf curl symptoms in Nicotiana benthamiana plants, but did not induce OLCD in okra. However, when these clones were individually co-inoculated with the cloned CLCuGB DNA, symptom severity and viral DNA levels were increased in N. benthamiana plants and typical OLCD symptoms were induced in okra. The CLCuGB was also replicated by, and increased symptom severity of, three monopartite tomato-infecting begomoviruses, including two from West Africa. The sequence of the DNA1 satellite was highly divergent, indicating that it represents a distinct West African lineage. DNA1 replicated autonomously, and replication required the DNA1-encoded Rep protein. Although DNA1 reduced helper begomovirus DNA levels, symptoms were not attenuated. In the presence of CLCuGB, DNA levels of the helper begomoviruses and DNA1 were substantially increased. Together, these findings establish that OLCD in Mali is caused by a complex of monopartite begomoviruses and a promiscuous betasatellite with an associated parasitic DNA1 satellite. These findings are discussed in terms of the aetiology of OLCD and the evolution of new begomovirus/satellite DNA complexes.

  13. The Epidemiology and Geographic Distribution of Relapsing Fever Borreliosis in West and North Africa, with a Review of the Ornithodoros erraticus Complex (Acari: Ixodida)

    PubMed Central

    Trape, Jean-François; Diatta, Georges; Arnathau, Céline; Bitam, Idir; Sarih, M’hammed; Belghyti, Driss; Bouattour, Ali; Elguero, Eric; Vial, Laurence; Mané, Youssouph; Baldé, Cellou; Pugnolle, Franck; Chauvancy, Gilles; Mahé, Gil; Granjon, Laurent; Duplantier, Jean-Marc

    2013-01-01

    Background Relapsing fever is the most frequent bacterial disease in Africa. Four main vector / pathogen complexes are classically recognized, with the louse Pediculus humanus acting as vector for B. recurrentis and the soft ticks Ornithodoros sonrai, O. erraticus and O. moubata acting as vectors for Borrelia crocidurae, B. hispanica and B. duttonii, respectively. Our aim was to investigate the epidemiology of the disease in West, North and Central Africa. Methods And Findings From 2002 to 2012, we conducted field surveys in 17 African countries and in Spain. We investigated the occurrence of Ornithodoros ticks in rodent burrows in 282 study sites. We collected 1,629 small mammals that may act as reservoir for Borrelia infections. Using molecular methods we studied genetic diversity among Ornithodoros ticks and Borrelia infections in ticks and small mammals. Of 9,870 burrows investigated, 1,196 (12.1%) were inhabited by Ornithodoros ticks. In West Africa, the southern and eastern limits of the vectors and Borrelia infections in ticks and small mammals were 13°N and 01°E, respectively. Molecular studies revealed the occurrence of nine different Ornithodoros species, including five species new for science, with six of them harboring Borrelia infections. Only B. crocidurae was found in West Africa and three Borrelia species were identified in North Africa: B. crocidurae, B. hispanica, and B. merionesi. Conclusions Borrelia Spirochetes responsible for relapsing fever in humans are highly prevalent both in Ornithodoros ticks and small mammals in North and West Africa but Ornithodoros ticks seem absent south of 13°N and small mammals are not infected in these regions. The number of Ornithodoros species acting as vector of relapsing fever is much higher than previously known. PMID:24223812

  14. Resisting Conformity: Anglican Mission Women and the Schooling of Girls in Early Nineteenth-Century West Africa

    ERIC Educational Resources Information Center

    Leach, Fiona

    2012-01-01

    The origins of modern schooling in early nineteenth-century Africa have been poorly researched. Moreover, histories of education in Africa have focused largely on the education of boys. Little attention has been paid to girls' schooling or to the missionary women who sought to construct a new feminine Christian identity for African girls. In the…

  15. Evaluation of soil moisture ensemble runs to estimate precipitation variability in convection-permitting model simulations for West Africa

    NASA Astrophysics Data System (ADS)

    Klüpfel, Vera; Kalthoff, Norbert; Gantner, Leonhard; Kottmeier, Christoph

    2011-07-01

    In this investigation, the impact of soil moisture on the precipitation amount and distribution in model simulations for West Africa was assessed. This included the examination of the dependence of precipitation on soil moisture, boundary layer parameters or convective conditions. For this purpose, different soil moisture fields from the rainy season of the year 2006 in West Africa were collected. These included three analysis fields, satellite measurements, and model output from the African Monsoon Multidisciplinary Analysis (AMMA) Land Surface Model Intercomparison Project. The different soil moisture fields were analyzed and compared first; large differences in the mean values, the north-south gradients, and the heterogeneity were revealed. The distributions were taken to initialize five convection-permitting model runs performed with the limited-area model COSMO (Consortium for Small-scale Modeling), forced by reanalyses from the European Centre for Medium-Range Weather Forecasts. A case study of a period with intense convective activity in the Sudanian and Sahelian zone was selected for the simulations. The simulated precipitation was compared with data from two satellite-based precipitation analyses and with forecasts from two global models of lower resolution. The model spread encompassed the precipitation analyses in the southern subdomain, while the latter lay far above the model results in the northern subdomain. The different soil moisture fields also influenced the turbulent fluxes at the surface, the boundary layer state and height as well as convective instability. Standard deviation of the simulations was highest for convective available potential energy, while the impact on convective inhibition was less pronounced. Only a weak negative relation of precipitation to soil moisture or conditional instability could be discerned. In this case, dry soil favored a higher boundary layer with better developed convective cells contributing to larger

  16. AMMA-CATCH a Hydrological, Meteorological and Ecological Long Term Observatory on West Africa : Some Recent Results

    NASA Astrophysics Data System (ADS)

    Galle, S.; Grippa, M.; Peugeot, C.; Bouzou Moussa, I.; Cappelaere, B.; Demarty, J.; Mougin, E.; Lebel, T.; Chaffard, V.

    2015-12-01

    AMMA-CATCH is a multi-scale observation system dedicated to long-term monitoring of the water cycle, the vegetation dynamics and their interaction with climate and water resources in West Africa. In the context of the global change, long-term observations are required to i) gain understanding in eco-hydrological processes over this highly contrasted region, ii) help their representation in Earth System Models, and iii) detect trends and infer their impacts on water resources and living conditions. It is made of three meso-scale sites (~ 1°x1°) in Mali, Niger and Benin, extending along the West African eco-climatic gradient. Within this regional window (5° by 9°), each of the three sites comprises a multi-scale set-up which helps documenting the components of the hydrologic budget and the evolutions of the surface conditions over a range of time scales: raingages, piezometers, river discharge stations, soil moisture and temperature profiles, turbulent fluxes measurements, LAI/biomass monitoring. This observation system has been continuously generating coherent datasets for 10 to 25 years depending on the datasets. It is jointly operated by French and African (Mali, Niger and Benin) research institutions. The data-base is available to the community through the website (www.amma-catch.org). AMMA-CATCH is a member of the French critical zone observatory network "Réseau des Bassins Versants", (RBV). AMMA-CATH participates to several global or regional observation networks, such as FluxNet, CarboAfrica, International Soil Moisture Networks (ISMN) and to calibration/validation campaigns for satellite missions such as SMOS (CNES, ESA), MEGHA-TROPIQUES (France/India) or SWAP(NASA). AMMA-CATCH fills a gap over a region, West Africa, where environmental data are largely lacking, and thus, it can usefully contribute to the international networking effort for environmental monitoring and research. Recent results on regional evolution of land cover, rainfall intensity and

  17. Poverty reduction in Africa

    PubMed Central

    Collier, Paul

    2007-01-01

    Poverty in Africa has been rising for the last quarter-century, while it has been falling in the rest of the developing world. Africa's distinctive problem is that its economies have not been growing. This article attempts to synthesize a range of recent research to account for this failure of the growth process. I argue that the reasons lie not in African peculiarities but rather in geographic features that globally cause problems but that are disproportionately pronounced in Africa. These features interact to create three distinct challenges that are likely to require international interventions beyond the conventional reliance on aid. PMID:17942702

  18. Poverty reduction in Africa.

    PubMed

    Collier, Paul

    2007-10-23

    Poverty in Africa has been rising for the last quarter-century, while it has been falling in the rest of the developing world. Africa's distinctive problem is that its economies have not been growing. This article attempts to synthesize a range of recent research to account for this failure of the growth process. I argue that the reasons lie not in African peculiarities but rather in geographic features that globally cause problems but that are disproportionately pronounced in Africa. These features interact to create three distinct challenges that are likely to require international interventions beyond the conventional reliance on aid.

  19. Ebola Virus Disease Epidemic: What Can the World Learn and Not Learn from West Africa?

    PubMed Central

    Azuine, Romuladus E.; Ekejiuba, Sussan E.; Singh, Gopal K.; Azuine, Magnus A.

    2015-01-01

    With over 4,500 deaths and counting, and new cases identified in two developed countries that are struggling and faltering in their handling of the epidemic, the 2014 Ebola Virus Disease (EVD) epidemic is unlike any of its kind ever encountered. The ability of some poor, resource-limited, developing countries in sub-Saharan Africa to efficiently handle the epidemic within their shores provides some lessons learned for the global health community. Among others, the 2014 EVD epidemic teaches us that it is time to put the “P” back in public and population health around the world. The global health community must support a sustainable strategy to mitigate Ebola virus and other epidemics both within and outside their shores, even after the cameras are gone. Ebola virus must not be called the disease of the poor and developing world. PMID:27621980

  20. Implementation of Information Communication Technology in the Teaching/Learning Process for Sustainable Development of Adults in West Africa Sub Sahara Region

    ERIC Educational Resources Information Center

    Nwobi, Anthonia; Ngozi, Ugwuoke; Rufina, Nwachukwu; Ogbonnaya, Kingsley A.

    2016-01-01

    This study examines the implementation of information technology in the teaching/learning process for sustainable development of adults in West Africa Sub Sahara Region (WASSR). Three research questions and two hypotheses guided the study. The population for the study was 3071 participants and instructors drawn from 10 education centres that were…

  1. Challenges Associated with the Content of the Art History Component in the General Knowledge in Art Subject: Implications for Art History Education in West Africa

    ERIC Educational Resources Information Center

    Adom, Dickson; Kquofi, Steve; Agyem, Joe Adu

    2016-01-01

    The content of the Art History component in the General Knowledge in Art subject studied by various Senior High Schools in West Africa is largely of foreign art histories at the expense of the histories of African indigenous arts which are shallowly presented in the teaching syllabus to be taught students. This makes the students appreciate more…

  2. Bibliographic analysis of scientific research on selected topics in public health nutrition in West Africa: Review of articles published from 1998 to 2008.

    PubMed

    Aaron, Grant J; Wilson, Shelby E; Brown, Kenneth H

    2010-01-01

    Few countries in West Africa have the capacity for carrying out advanced training in nutrition and public health. To provide additional information on current regional applied nutrition research capacity and productivity, we analysed peer-reviewed articles on key public health nutrition topics that were published from 1998 to 2008. Using MEDLINE/PubMed, the following terms were searched: 'breast feeding', 'infant nutrition physiology' (comprising complementary feeding and weaning), 'protein energy malnutrition', 'nutrition and infection', 'vitamin A', 'iodine', 'zinc' and 'overweight', each linked with the term 'Western Africa'. In total, 412 unique articles (37±6 articles per year) were identified. Most research focused on infant and young child feeding practices, selected micronutrient deficiencies, and the emerging problem of overweight and obesity. The primary author of nearly half (46%) the publications was located in an institution outside of West Africa. Most articles were published in English (90%), and nearly half of all articles (41%) were cross-sectional studies. Our findings indicate that few peer-reviewed research studies are being published on key public health topics in the West African region, considering the magnitude of nutrition problems in this region. New approaches are needed to encourage and support research capacity and output in West Africa.

  3. Development of reference transcriptomes for the major insect pests of cowpea: a toolbox for insect pest management approaches in West Africa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cowpea crops are widely cultivated and a major nutritional source of protein for indigenous human populations in West Africa. Annual yields and longevity of grain storage is greatly reduced by feeding damage caused by a complex of insect pests that include Anoplocnemis curvipes, Aphis craccivora, Cl...

  4. The Impact of Human Conflict on the Genetics of Mastomys natalensis and Lassa Virus in West Africa

    PubMed Central

    Denys, Christiane; ter Meulen, Jan; Wirth, Thierry

    2012-01-01

    Environmental changes have been shown to play an important role in the emergence of new human diseases of zoonotic origin. The contribution of social factors to their spread, especially conflicts followed by mass movement of populations, has not been extensively investigated. Here we reveal the effects of civil war on the phylogeography of a zoonotic emerging infectious disease by concomitantly studying the population structure, evolution and demography of Lassa virus and its natural reservoir, the rodent Mastomys natalensis, in Guinea, West Africa. Analysis of nucleoprotein gene sequences enabled us to reconstruct the evolutionary history of Lassa virus, which appeared 750 to 900 years ago in Nigeria and only recently spread across western Africa (170 years ago). Bayesian demographic inferences revealed that both the host and the virus populations have gone recently through severe genetic bottlenecks. The timing of these events matches civil war-related mass movements of refugees and accompanying environmental degradation. Forest and habitat destruction and human predation of the natural reservoir are likely explanations for the sharp decline observed in the rodent populations, the consequent virus population decline, and the coincident increased incidence of Lassa fever in these regions. Interestingly, we were also able to detect a similar pattern in Nigeria coinciding with the Biafra war. Our findings show that anthropogenic factors may profoundly impact the population genetics of a virus and its reservoir within the context of an emerging infectious disease. PMID:22615894

  5. Cryptomyrus: a new genus of Mormyridae (Teleostei, Osteoglossomorpha) with two new species from Gabon, West-Central Africa.

    PubMed

    Sullivan, John P; Lavoué, Sébastien; Hopkins, Carl D

    2016-01-01

    We use mitochondrial and nuclear sequence data to show that three weakly electric mormyrid fish specimens collected at three widely separated localities in Gabon, Africa over a 13-year period represent an unrecognized lineage within the subfamily Mormyrinae and determine its phylogenetic position with respect to other taxa. We describe these three specimens as a new genus containing two new species. Cryptomyrus, new genus, is readily distinguished from all other mormyrid genera by a combination of features of squamation, morphometrics, and dental attributes. Cryptomyrus ogoouensis, new species, is differentiated from its single congener, Cryptomyrus ona, new species, by the possession of an anal-fin origin located well in advance of the dorsal fin, a narrow caudal peduncle and caudal-fin lobes nearly as long as the peduncle. In Cryptomyrus ona, the anal-fin origin is located only slightly in advance of the dorsal fin, the caudal peduncle is deep and the caudal-fin lobes considerably shorter than the peduncle. Continued discovery of new taxa within the "Lower Guinea Clade" of Mormyridae highlights the incompleteness of our knowledge of fish diversity in West-Central Africa. We present a revised key to the mormyrid genera of Lower Guinea.

  6. The impact of human conflict on the genetics of Mastomys natalensis and Lassa virus in West Africa.

    PubMed

    Lalis, Aude; Leblois, Raphaël; Lecompte, Emilie; Denys, Christiane; Ter Meulen, Jan; Wirth, Thierry

    2012-01-01

    Environmental changes have been shown to play an important role in the emergence of new human diseases of zoonotic origin. The contribution of social factors to their spread, especially conflicts followed by mass movement of populations, has not been extensively investigated. Here we reveal the effects of civil war on the phylogeography of a zoonotic emerging infectious disease by concomitantly studying the population structure, evolution and demography of Lassa virus and its natural reservoir, the rodent Mastomys natalensis, in Guinea, West Africa. Analysis of nucleoprotein gene sequences enabled us to reconstruct the evolutionary history of Lassa virus, which appeared 750 to 900 years ago in Nigeria and only recently spread across western Africa (170 years ago). Bayesian demographic inferences revealed that both the host and the virus populations have gone recently through severe genetic bottlenecks. The timing of these events matches civil war-related mass movements of refugees and accompanying environmental degradation. Forest and habitat destruction and human predation of the natural reservoir are likely explanations for the sharp decline observed in the rodent populations, the consequent virus population decline, and the coincident increased incidence of Lassa fever in these regions. Interestingly, we were also able to detect a similar pattern in Nigeria coinciding with the Biafra war. Our findings show that anthropogenic factors may profoundly impact the population genetics of a virus and its reservoir within the context of an emerging infectious disease.

  7. Analysis of the bacterial community composition in acidic well water used for drinking in Guinea-Bissau, West Africa.

    PubMed

    Machado, Ana; Bordalo, Adriano A

    2014-08-01

    Potable water is a resource out of reach for millions worldwide, and the available water may be chemically and microbiologically compromised. This is particularly acute in Africa, where water-networks may be non-existent or restricted to a small fraction of the urban population, as in the case of Guinea-Bissau, West Africa. This study was carried out seasonally in Bolama (11°N), where unprotected hand-dug wells with acidic water are the sole source of water for the population. We inspected the free-living bacterial community dynamics by automated rRNA intergenic spacer analyses, quantitative polymerase chain reaction and cloning approaches. The results revealed a clear seasonal shift in bacterial assemblage composition and microbial abundance within the same sampling site. Temperature, pH and turbidity, together with the infiltration and percolation of surface water, which takes place in the wet season, seemed to be the driving factors in the shaping and selection of the bacterial community and deterioration of water quality. Analysis of 16S rDNA sequences revealed several potential pathogenic bacteria and uncultured bacteria associated with water and sediments, corroborating the importance of a culture-independent approach in drinking water monitoring.

  8. Residence times of shallow groundwater in West Africa: implications for hydrogeology and resilience to future changes in climate

    NASA Astrophysics Data System (ADS)

    Lapworth, D. J.; MacDonald, A. M.; Tijani, M. N.; Darling, W. G.; Gooddy, D. C.; Bonsor, H. C.; Araguás-Araguás, L. J.

    2013-05-01

    Although shallow groundwater (<50 mbgl) sustains the vast majority of improved drinking-water supplies in rural Africa, there is little information on how resilient this resource may be to future changes in climate. This study presents results of a groundwater survey using stable isotopes, CFCs, SF6, and 3H across different climatic zones (annual rainfall 400-2,000 mm/year) in West Africa. The purpose was to quantify the residence times of shallow groundwaters in sedimentary and basement aquifers, and investigate the relationship between groundwater resources and climate. Stable-isotope results indicate that most shallow groundwaters are recharged rapidly following rainfall, showing little evidence of evaporation prior to recharge. Chloride mass-balance results indicate that within the arid areas (<400 mm annual rainfall) there is recharge of up to 20 mm/year. Age tracers show that most groundwaters have mean residence times (MRTs) of 32-65 years, with comparable MRTs in the different climate zones. Similar MRTs measured in both the sedimentary and basement aquifers suggest similar hydraulic diffusivity and significant groundwater storage within the shallow basement. This suggests there is considerable resilience to short-term inter-annual variation in rainfall and recharge, and rural groundwater resources are likely to sustain diffuse, low volume abstraction.

  9. Alcohol use and non-adherence to antiretroviral therapy in HIV-infected patients in West Africa

    PubMed Central

    Antoine, Jaquet; Ekouevi Didier, K; Jules, Bashi; Maiga, Aboubakrine; Eugène, Messou; Moussa, Maiga; Alassane, Traore Hamar; Djimon, Zannou Marcel; Calixte, Guehi; Olivier, Ba-Gomis Franck; Albert, Minga; Gérard, Allou; Paul, Eholie Serge; Emmanuel, Bissagnene; Sasco Annie, J; Francois, Dabis

    2015-01-01

    AIM To investigate the association between alcohol use and adherence to Highly Active Antiretroviral Treatment (HAART) among HIV-infected patients in sub-Saharan Africa. DESIGN and MEASURES Cross sectional survey conducted in eight adult HIV treatment centers from Benin, Côte d’Ivoire and Mali. During a four-week period, health workers administered the Alcohol Use Disorders Identification Test to HAART-treated patients and assessed treatment adherence using the AIDS Clinical Trials Group follow-up questionnaire. RESULTS A total of 2920 patients were enrolled with a median age of 38 years (IQR 32–45 years) and a median duration on HAART of 3 years (IQR 1–4 years). Overall, 91.8% of patients were identified as adherent to HAART. Non-adherence was associated with current drinking (OR 1.4; 95% CI 1.1–2.0), hazardous drinking (OR 4.7; 95% CI 2.6–8.6) and was inversely associated with a history of counseling on adherence (OR 0.7; 95% CI 0.5–0.9). CONCLUSION Alcohol consumption and hazardous drinking is associated with non-adherence to HAART among HIV-infected patients from West Africa. thus providing a framework for developing and reinforcing the necessary prevention and intervention strategies. PMID:20528816

  10. Cryptomyrus: a new genus of Mormyridae (Teleostei, Osteoglossomorpha) with two new species from Gabon, West-Central Africa

    PubMed Central

    Sullivan, John P.; Lavoué, Sébastien; Hopkins, Carl D.

    2016-01-01

    Abstract We use mitochondrial and nuclear sequence data to show that three weakly electric mormyrid fish specimens collected at three widely separated localities in Gabon, Africa over a 13-year period represent an unrecognized lineage within the subfamily Mormyrinae and determine its phylogenetic position with respect to other taxa. We describe these three specimens as a new genus containing two new species. Cryptomyrus, new genus, is readily distinguished from all other mormyrid genera by a combination of features of squamation, morphometrics, and dental attributes. Cryptomyrus ogoouensis, new species, is differentiated from its single congener, Cryptomyrus ona, new species, by the possession of an anal-fin origin located well in advance of the dorsal fin, a narrow caudal peduncle and caudal-fin lobes nearly as long as the peduncle. In Cryptomyrus ona, the anal-fin origin is located only slightly in advance of the dorsal fin, the caudal peduncle is deep and the caudal-fin lobes considerably shorter than the peduncle. Continued discovery of new taxa within the “Lower Guinea Clade” of Mormyridae highlights the incompleteness of our knowledge of fish diversity in West-Central Africa. We present a revised key to the mormyrid genera of Lower Guinea. PMID:27006619

  11. High Resolution Simulations of Future Climate in West Africa Using a Variable-Resolution Atmospheric Model

    NASA Astrophysics Data System (ADS)

    Adegoke, J. O.; Engelbrecht, F.; Vezhapparambu, S.

    2013-12-01

    In previous work demonstrated the application of a var¬iable-resolution global atmospheric model, the conformal-cubic atmospheric model (CCAM), across a wide range of spatial and time scales to investigate the ability of the model to provide realistic simulations of present-day climate and plausible projections of future climate change over sub-Saharan Africa. By applying the model in stretched-grid mode the versatility of the model dynamics, numerical formulation and physical parameterizations to function across a range of length scales over the region of interest, was also explored. We primarily used CCAM to illustrate the capability of the model to function as a flexible downscaling tool at the climate-change time scale. Here we report on additional long term climate projection studies performed by downscaling at much higher resolutions (8 Km) over an area that stretches from just south of Sahara desert to the southern coast of the Niger Delta and into the Gulf of Guinea. To perform these simulations, CCAM was provided with synoptic-scale forcing of atmospheric circulation from 2.5 deg resolution NCEP reanalysis at 6-hourly interval and SSTs from NCEP reanalysis data uses as lower boundary forcing. CCAM 60 Km resolution downscaled to 8 Km (Schmidt factor 24.75) then 8 Km resolution simulation downscaled to 1 Km (Schmidt factor 200) over an area approximately 50 Km x 50 Km in the southern Lake Chad Basin (LCB). Our intent in conducting these high resolution model runs was to obtain a deeper understanding of linkages between the projected future climate and the hydrological processes that control the surface water regime in this part of sub-Saharan Africa.

  12. Nutritional and economic benefits of Leucaena and Gliricidia as feed supplements for small ruminants in humid West Africa.

    PubMed

    Jabbar, M A; Reynolds, L; Larbi, A; Smith, J

    1997-02-01

    Considering leguminous trees Leucaena and Gliricidia as good sources of quality food, on-station and on-farm studies were conducted in the humid zone of West Africa to establish animal responses to levels, times and forms of browse supplementation, to develop alternative feeding strategies for utilising limited feed supply and to assess the economic benefits of feed supplements as against the use of tree foliage as mulch for crop production. Results indicate that at any level of supplement, sheep grew twice as fast as goats. The main benefits of supplementation came through increased growth and survival. Form and level of supplementation had significant effect on intake. Economic analyses showed that crop response to mulching was the principal competing determinant of whether the use of tree foliage as feed supplement was economic.

  13. Required duration of combined annual ivermectin treatment and vector control in the Onchocerciasis Control Programme in west Africa.

    PubMed Central

    Plaisier, A. P.; Alley, E. S.; van Oortmarssen, G. J.; Boatin, B. A.; Habbema, J. D.

    1997-01-01

    In the extension areas of the Onchocerciasis Control Programme in West Africa, aerial larviciding is supplemented with annual ivermectin treatment, mainly to achieve better control of morbidity. The purpose of this study is to determine whether and to what extent the addition of annual ivermectin treatment permits earlier cessation of vector control than originally recommended. The effectiveness of combined ivermectin distribution and vector control was assessed using an epidemiological model. Model predictions suggest that, dependent on the pre-control endemicity of the area and the proportion of persons treated during each ivermectin round, large-scale annual treatment permits a considerable reduction in the duration of vector control. Taking into account uncertainty about the efficacy of ivermectin, our results indicate that, provided treatment coverage is at least 65% and there is no importation of infection from elsewhere, 12 years of combined control will be sufficient to reduce the risk of recrudescence to below 1% in even the most afflicted areas. PMID:9277011

  14. Contemporary Problems in Africa.

    ERIC Educational Resources Information Center

    O'Meara, Patrick; Winchester, N. Brian

    1987-01-01

    Provides a brief overview of political and economic developments of the past 25 years in Africa. Maintains this was a period of experimentation with vast differences in the ways in which governments dealt with human and natural problems. (JDH)

  15. Child Labour in Africa.

    ERIC Educational Resources Information Center

    Bonnet, Michel

    1993-01-01

    The question of child labor in Africa is complicated by the failures of the educational system, family relations, traditional forms of apprenticeship, proliferation of the informal economic sector, and continuing existence of a rural economy. Hazardous working conditions prevail. (SK)

  16. Microsatellite analysis supports clonal propagation and reduced divergence of Trypanosoma vivax from asymptomatic to fatally infected livestock in South America compared to West Africa

    PubMed Central

    2014-01-01

    Background Mechanical transmission of the major livestock pathogen Trypanosoma vivax by other biting flies than tsetse allows its spread from Africa to the New World. Genetic studies are restricted to a small number of isolates and based on molecular markers that evolve too slowly to resolve the relationships between American and West African populations and, thus, unable us to uncover the recent history of T. vivax in the New World. Methods T. vivax genetic diversity, population structure and the source of outbreaks was investigated through the microsatellite multiloci (7 loci) genotype (MLGs) analysis in South America (47isolates from Brazil, Venezuela and French Guiana) and West Africa (12 isolates from The Gambia, Burkina Faso, Ghana, Benin and Nigeria). Relationships among MLGs were explored using phylogenetic, principal component and STRUCTURE analyses. Results Although closely phylogenetically related, for the first time, genetic differences were detected between T. vivax isolates from South America (11 genotypes/47 isolates) and West Africa (12 genotypes/12 isolates) with no MLGs in common. Diversity was far greater across West Africa than in South America, where genotypes from Brazil (MLG1-6), Venezuela (MLG7-10) and French Guiana (MLG11) shared similar but not identical allele composition. No MLG was exclusive to asymptomatic (endemic areas) or sick (outbreaks in non-endemic areas) animals, but only MLGs1, 2 and 3 were responsible for severe haematological and neurological disorders. Conclusions Our results revealed closely related genotypes of T. vivax in Brazil and Venezuela, regardless of endemicity and clinical conditions of the infected livestock. The MLGs analysis from T. vivax across SA and WA support clonal propagation, and is consistent with the hypothesis that the SA populations examined here derived from common ancestors recently introduced from West Africa. The molecular markers defined here are valuable to assess the genetic diversity, to

  17. Astronomy Landscape in Africa

    NASA Astrophysics Data System (ADS)

    Nemaungani, Takalani

    2015-01-01

    The vision for astronomy in Africa is embedded in the African Space Policy of the African Union in early 2014. The vision is about positioning Africa as an emerging hub for astronomy sciences and facilities. Africa recognized the need to take advantage of its natural resource, the geographical advantage of the clear southern skies and pristine sites for astronomy. The Pan African University (PAU) initiative also presents an opportunity as a post-graduate training and research network of university nodes in five regions of Africa and supported by the African Union. The Southern African node based in South Africa concentrates on space sciences which also includes astronomy. The PAU aims to provide the opportunity for advanced graduate training and postgraduate research to high-performing African students. Objectives also include promoting mobility of students and teachers and harmonizing programs and degrees.A number of astronomy initiatives have burgeoned in the Southern African region and these include the Southern Africa Largest Optical Telescope (SALT), HESS (High Energy Stereoscopic System), the SKA (Square Kilometre Array) and the AVN (African Very Long Baseline Interferometer Network). There is a growing appetite for astronomy sciences in Africa. In East Africa, the astronomy community is well organized and is growing - the East African Astronomical society (EAAS) held its successful fourth annual conference since 2010 on 30 June to 04 July 2014 at the University of Rwanda. Centred around the 'Role of Astronomy in Socio-Economic Transformation,' this conference aimed at strengthening capacity building in Astronomy, Astrophysics and Space Science in general, while providing a forum for astronomers from the region to train young and upcoming scientists.

  18. AIDS in Africa

    DTIC Science & Technology

    2006-03-09

    have recommended that Africans infected with HIV be treated with an antibiotic/ sulfa drug combination known as cotrimoxazole in order to prevent...response is the subject of much debate. An estimated 500,000 Africa AIDS patients were being treated with antiretroviral drugs in mid-2005, up from 150,000...whether drugs can be made widely accessible without costly health infrastructure improvements. U.S. concern over AIDS in Africa grew in the 1980s, as the

  19. Profile of South Africa

    SciTech Connect

    Fox, G.J.; Tonneson, L.C.

    1996-08-01

    A broad overview of the Republic of South Africa`s nuclear energy program is presented. Economic aspects are the main focus of the article, and numerical data is provided for electricity generation and use and uranium production. The role of the molecular laser isotope process for enrichment is discussed. The research reactor program, waste disposal and decommissioning, mining history, uranium production, and nonproliferation policy are other highlighted topics.

  20. Consistent rainy season changes predicted from Regional Climate Models ensembles indicate threats to crop production in West Africa

    NASA Astrophysics Data System (ADS)

    Wisser, D.; Sylla, M. B.; Ibrahim, B.

    2014-12-01

    Agricultural production in West Africa is extremely vulnerable to precipitation change and variability. Designing adaptation options to anticipate these changes in precipitation requires robust predicting future climate conditions. Output from Global Circulation Models (GCMs) is too coarse to be used directly to assess regional and high order statistics changes. We use output from a set of Regional Climate Models that dynamically downscale CMIP5 GCMs and analyze mid-century changes in the characteristics of precipitation in West Africa over cropland areas. For each RCM/GCM combinations, we compared predicted precipitation for the period 2035-2065 under the RCP 8.5 scenario with its historical reconstruction of 1975-2005. The mean changes emerging from an analysis of the ensemble of 15 RCM/GCM combinations suggest moderate (~3%) increases in annual precipitation,a very consistent delay in the onset of the rainy season (1 to 4 days from South to North) and no consistent change in the ending of the rainy season. This illustrates a general shortening of the rainy season. An analysis of dry spells (periods of consecutive days with less than 5 mm) for a durations of between 5 and 15 days revealed an increased probability of experiencing longer dry spells during the rainy season in the future climate, coupled with a general intensification of precipitation. This finding was consistent across all models. Our analysis promotes regional prioritization of adaptation measures to the changes in precipitation characteristics that could potentially have detrimental effects on crop yields while also affecting water resources management, species distribution, and others sectors. Increased storage of water, in combination with supplemental irrigation can be an important mechanism for adapting to the effects for regional precipitation changes on crop yield.

  1. Heterogeneity in District-Level Transmission of Ebola Virus Disease during the 2013-2015 Epidemic in West Africa

    PubMed Central

    Gsteiger, Sandro; Low, Nicola; Hansen, Christian H.; Althaus, Christian L.

    2016-01-01

    The Ebola virus disease (EVD) epidemic in West Africa in 2013–2015 spread heterogeneously across the three hardest-hit countries Guinea, Liberia and Sierra Leone and the estimation of national transmission of EVD provides little information about local dynamics. To investigate district-level transmissibility of EVD, we applied a statistical modelling approach to estimate the basic reproduction number (R0) for each affected district and each country using weekly incident case numbers. We estimated growth rates during the early exponential phase of the outbreak using exponential regression of the case counts on the first eight weeks since onset. To take into account the heterogeneity between and within countries, we fitted a mixed effects model and calculated R0 based on the predicted individual growth rates and the reported serial interval distribution. At district level, R0 ranged from 0.36 (Dubréka) to 1.72 (Beyla) in Guinea, from 0.53 (Maryland) to 3.37 (Margibi) in Liberia and from 1.14 (Koinadugu) to 2.73 (Western Rural) in Sierra Leone. At national level, we estimated an R0 of 0.97 (95% CI 0.77–1.18) for Guinea, 1.26 (95% CI 0.98–1.55) for Liberia and 1.66 (95% CI 1.32–2.00) for Sierra Leone. Socio-demographic variables related to urbanisation such as high population density and high wealth index were found positively associated with R0 suggesting that the consequences of fast urban growth in West Africa may have contributed to the increased spread of EVD. PMID:27434164

  2. Impact of land surface properties on convection in a 40 day convection-permitting simulation over West Africa

    NASA Astrophysics Data System (ADS)

    Taylor, Christopher; Birch, Cathryn; Dixon, Nick; Parker, Douglas

    2013-04-01

    Land surface properties influence the life cycle of convective systems across West Africa via space-time variability in sensible and latent heat fluxes. Previous observational and modelling studies have shown that areas with strong mesoscale variability in vegetation cover or soil moisture induce coherent structures in the daytime planetary boundary layer. In particular, horizontal gradients in sensible heat flux can induce convergence zones which favour the initiation of deep convection. A recent study based on satellite data (Taylor et al. Nature Geoscience 2011), illustrated the climatological importance of soil moisture gradients in the initiation of long-lived Mesoscale Convective Systems (MCS) in the Sahel. Here we explore the relationships between MCS life-cycles and the underlying surface using a unique convection-permitting simulation over West Africa during the wet season. Under the UK CASCADE project, the Met Office Unified Model was run with a grid length of 4km over a domain of 4000 x 3000 km for the period 25th July to 2nd September 2006. Over the course of the integration, the model generates a large population of MCS to analyse, each creating new soil moisture structures which in turn can feed back on the atmosphere. We track simulated MCS developing in varied environments and examine how land surface features influence convective initiation. We find strong consistency between the previous analysis of satellite data and the model. Specifically, the model captures the observed preference for convective initiation close to strong soil moisture gradients, with storms developing on the upwind side of transitions from dry to wet soil. The model clearly illustrates the pre-storm surface-induced circulation previously hypothesised to be responsible for the land-atmosphere coupling.

  3. Social and cultural aspects of HIV and AIDS in West Africa: a narrative review of qualitative research.

    PubMed

    Samuelsen, Helle; Norgaard, Ole; Ostergaard, Lise Rosendal

    2012-01-01

    With the increasing focus on the role of social aspects of the HIV epidemic in sub-Saharan Africa, the need for an overview of existing research dealing with such issues has become more urgent. The objective of this article is to provide a thematic overview of existing qualitative research on HIV and AIDS in the West African region and to analyze the main research findings in order to identify possible gaps and recommend new research themes to inform future research-based interventions. The analysis is based on a total of 58 articles published from 2001 to 2009 in English or French identified through a literature search in seven scientific, bibliographical databases. Searches included terms related to qualitative studies combined with various terms related to HIV/AIDS. The results of this narrative review show that there was a geographical concentration on Nigeria, Ghana, Burkina Faso and Côte d'Ivoire and a strong urban bias, with most studies taking place in the capital cities of these countries. The majority of the studies focused on women or women and men; only four articles dealt exclusively with men, of which only two were on men who have sex with men. The main study groups were people living with HIV, young people or female sex workers. Sexual risk-taking and stigmatization were the themes that were most prominently explored in the articles we reviewed. We conclude that research needs to be strengthened in relation to the analysis of experiences with antiretroviral therapy and the non-optimal access to treatment in West Africa. Also, more research is needed on men and their exposure to HIV/AIDS, as well as on the role of concurrent partnership in the spread of HIV.

  4. Embargo on Lion Hunting Trophies from West Africa: An Effective Measure or a Threat to Lion Conservation?

    PubMed

    Bouché, Philippe; Crosmary, William; Kafando, Pierre; Doamba, Benoit; Kidjo, Ferdinand Claude; Vermeulen, Cédric; Chardonnet, Philippe

    2016-01-01

    The W-Arly-Pendjari (WAP) ecosystem, shared among Benin, Burkina Faso and Niger, represents the last lion stronghold of West Africa. To assess the impact of trophy hunting on lion populations in hunting areas of the WAP, we analyzed trends in harvest rates from 1999 to 2014. We also investigated whether the hunting areas with higher initial hunting intensity experienced steeper declines in lion harvest between 1999 and 2014, and whether lion densities in hunting areas were lower than in national parks. Lion harvest rate remained overall constant in the WAP. At initial hunting intensities below 1.5 lions/1000km2, most hunting areas experienced an increase in lion harvest rate, although that increase was of lower magnitude for hunting areas with higher initial hunting intensity. The proportion of hunting areas that experienced a decline in lion harvest rate increased at initial hunting intensities above 1.5 lions/1000km2. In 2014, the lion population of the WAP was estimated with a spoor count at 418 (230-648) adults and sub-adult individuals, comparable to the 311 (123-498) individuals estimated in the previous 2012 spoor survey. We found no significant lion spoor density differences between national parks and hunting areas. Hunting areas with higher mean harvest rates did not have lower lion densities. The ratio of large adult males, females and sub-adults was similar between the national parks and the hunting areas. These results suggested that the lion population was not significantly affected by hunting in the WAP. We concluded that a quota of 1 lion/1000km2 would be sustainable for the WAP. Based on our results, an import embargo on lion trophies from the WAP would not be justified. It could ruin the incentive of local actors to conserve lions in hunting areas, and lead to a drastic reduction of lion range in West Africa.

  5. Embargo on Lion Hunting Trophies from West Africa: An Effective Measure or a Threat to Lion Conservation?

    PubMed Central

    Bouché, Philippe; Crosmary, William; Kafando, Pierre; Doamba, Benoit; Kidjo, Ferdinand Claude; Vermeulen, Cédric; Chardonnet, Philippe

    2016-01-01

    The W-Arly-Pendjari (WAP) ecosystem, shared among Benin, Burkina Faso and Niger, represents the last lion stronghold of West Africa. To assess the impact of trophy hunting on lion populations in hunting areas of the WAP, we analyzed trends in harvest rates from 1999 to 2014. We also investigated whether the hunting areas with higher initial hunting intensity experienced steeper declines in lion harvest between 1999 and 2014, and whether lion densities in hunting areas were lower than in national parks. Lion harvest rate remained overall constant in the WAP. At initial hunting intensities below 1.5 lions/1000km2, most hunting areas experienced an increase in lion harvest rate, although that increase was of lower magnitude for hunting areas with higher initial hunting intensity. The proportion of hunting areas that experienced a decline in lion harvest rate increased at initial hunting intensities above 1.5 lions/1000km2. In 2014, the lion population of the WAP was estimated with a spoor count at 418 (230–648) adults and sub-adult individuals, comparable to the 311 (123–498) individuals estimated in the previous 2012 spoor survey. We found no significant lion spoor density differences between national parks and hunting areas. Hunting areas with higher mean harvest rates did not have lower lion densities. The ratio of large adult males, females and sub-adults was similar between the national parks and the hunting areas. These results suggested that the lion population was not significantly affected by hunting in the WAP. We concluded that a quota of 1 lion/1000km2 would be sustainable for the WAP. Based on our results, an import embargo on lion trophies from the WAP would not be justified. It could ruin the incentive of local actors to conserve lions in hunting areas, and lead to a drastic reduction of lion range in West Africa. PMID:27182985

  6. A Landscape-based model for predicting Mycobacterium ulcerans infection (Buruli Ulcer disease) presence in Benin, West Africa.

    PubMed

    Wagner, Tyler; Benbow, M Eric; Burns, Meghan; Johnson, R Christian; Merritt, Richard W; Qi, Jiaguo; Small, Pamela L C

    2008-03-01

    Mycobacterium ulcerans infection (Buruli ulcer [BU] disease) is an emerging tropical disease that causes severe morbidity in many communities, especially those in close proximity to aquatic environments. Research and control efforts are severely hampered by the paucity of data regarding the ecology of this disease; for example, the vectors and modes of transmission remain unknown. It is hypothesized that BU presence is associated with altered landscapes that perturb aquatic ecosystems; however, this has yet to be quantified over large spatial scales. We quantified relationships between land use/land cover (LULC) characteristics surrounding individual villages and BU presence in Benin, West Africa. We also examined the effects of other village-level characteristics which we hypothesized to affect BU presence, such as village distance to the nearest river. We found that as the percent urban land use in a 50-km buffer surrounding a village increased, the probability of BU presence decreased. Conversely, as the percent agricultural land use in a 20-km buffer surrounding a village increased, the probability of BU presence increased. Landscape-based models had predictive ability when predicting BU presence using validation data sets from Benin and Ghana, West Africa. Our analyses suggest that relatively small amounts of urbanization are associated with a decrease in the probability of BU presence, and we hypothesize that this is due to the increased availability of pumped water in urban environments. Our models provide an initial approach to predicting the probability of BU presence over large spatial scales in Benin and Ghana, using readily available land use data.

  7. Projecting Future Land Use Changes in West Africa Driven by Climate and Socioeconomic Factors: Uncertainties and Implications for Adaptation

    NASA Astrophysics Data System (ADS)

    Wang, G.; Ahmed, K. F.; You, L.

    2015-12-01

    Land use changes constitute an important regional climate change forcing in West Africa, a region of strong land-atmosphere coupling. At the same time, climate change can be an important driver for land use, although its importance relative to the impact of socio-economic factors may vary significant from region to region. This study compares the contributions of climate change and socioeconomic development to potential future changes of agricultural land use in West Africa and examines various sources of uncertainty using a land use projection model (LandPro) that accounts for the impact of socioeconomic drivers on the demand side and the impact of climate-induced crop yield changes on the supply side. Future crop yield changes were simulated by a process-based crop model driven with future climate projections from a regional climate model, and future changes of food demand is projected using a model for policy analysis of agricultural commodities and trade. The impact of human decision-making on land use was explicitly considered through multiple "what-if" scenarios to examine the range of uncertainties in projecting future land use. Without agricultural intensification, the climate-induced decrease of crop yield together with increase of food demand are found to cause a significant increase in agricultural land use at the expense of forest and grassland by the mid-century, and the resulting land use land cover changes are found to feed back to the regional climate in a way that exacerbates the negative impact of climate on crop yield. Analysis of results from multiple decision-making scenarios suggests that human adaptation characterized by science-informed decision making to minimize land use could be very effective in many parts of the region.

  8. Evaluation of 2001 springtime CO transport over West Africa using MOPITT CO measurements assimilated in a global chemistry transport model

    NASA Astrophysics Data System (ADS)

    Pradier, Stéphanie; Attié, Jean-Luc; Chong, Michel; Escobar, Juan; Peuch, Vincent-Henri; Lamarque, Jean-François; Khattatov, Boris; Edwards, David

    2006-07-01

    The global chemistry and transport model MOCAGE (Modèle de Chimie Atmosphérique à Grande Echelle) is used to investigate the contribution of transport to the carbon monoxide (CO) distribution over West Africa during spring 2001. It is constrained with the CO profiles provided by the Measurements Of Pollution In The Troposphere (MOPITT) instrument through a sequential assimilation technique based on a suboptimal Kalman filter. The improvement of tropospheric CO distribution from MOCAGE is evaluated by comparing the model results (with and without assimilation) with the MOPITT CO concentrations observed during the analysed period (between 2001 March 15 to 2001 April 30), and also with independent in situ CMDL and TRACE-P observations. The initial overestimation in high CO emissions areas (Africa, SE Asia and NW coast of South America) is considerably reduced by using the MOPITT CO assimilation. We analysed the assimilated CO for a period of three successive 15 d periods in terms of average fields over West Africa and contributions to the CO budget of transport and chemical sources. It is found that the horizontal and vertical CO distributions are strongly dependent on the characteristics of the large-scale flows during spring, marked by the onset of the low-level southerly monsoon flow and the gradual increase of the well-known African and tropical easterly jets at middle and upper levels, respectively. Total transport by the mean flow (horizontal plus vertical advection) is important in the CO budget since it mostly compensates the local sink or source generated by chemical reactions and small-scale processes. The major source of CO is concentrated in the lower troposphere (1000-800 hPa) mainly due to convergent low-level flow advecting CO from surrounding regions and surface emissions (biomass burning). Vertical transport removes 70% of this low-level CO and redistributes it in the middle troposphere (800-400 hPa) where chemical reactions and horizontal exports

  9. Decolonizing Bioethics in Africa

    PubMed Central

    Macaulay-Adeyelure, O.C.

    2017-01-01

    The global spread of bioethics from its North-American and European provenance to non-Western societies is currently raising some concerns. Part of the concern has to do with whether or not the exportation of bioethics in its full Western sense to developing non-Western states is an instance of ethical imperialism or bioethical neocolonialism. This paper attempts an exploration of this debate in the context of bioethics in sub-Saharan Africa. Rather than conceding that bioethics has a colonial agenda in Africa, this paper defends the position that the current bioethics trend in sub-Saharan Africa is an unintended imperialistic project. It argues that its colonizing character is not entirely a product of the Western programmed goals of training and institution building; rather, it is a structural consequence of many receptive African minds and institutions. Though bioethics in Africa is turning out as a colonizing project, one serious implication of such trend, if unchecked urgently, is that bioethics’ invaluable relevance to Africa is being incapacitated. This paper, therefore, attempts a decolonizing trajectory of bioethics in Africa. Contrary to the pretense of ‘African bioethics,’ which some African scholars are now defending, this paper through the logic of decolonization makes case for ‘bioethics in Africa’. In such logic, the principle of existential needs is prioritized over the principle of identity and authenticity that define African voice in bioethics. PMID:28344985

  10. First Report of Outbreaks of the Fall Armyworm Spodoptera frugiperda (J E Smith) (Lepidoptera, Noctuidae), a New Alien Invasive Pest in West and Central Africa.

    PubMed

    Goergen, Georg; Kumar, P Lava; Sankung, Sagnia B; Togola, Abou; Tamò, Manuele

    2016-01-01

    The fall armyworm Spodoptera frugiperda is a prime noctuid pest of maize on the American continents where it has remained confined despite occasional interceptions by European quarantine services in recent years. The pest has currently become a new invasive species in West and Central Africa where outbreaks were recorded for the first time in early 2016. The presence of at least two distinct haplotypes within samples collected on maize in Nigeria and São Tomé suggests multiple introductions into the African continent. Implications of this new threat to the maize crop in tropical Africa are briefly discussed.

  11. First Report of Outbreaks of the Fall Armyworm Spodoptera frugiperda (J E Smith) (Lepidoptera, Noctuidae), a New Alien Invasive Pest in West and Central Africa

    PubMed Central

    Sankung, Sagnia B.; Togola, Abou; Tamò, Manuele

    2016-01-01

    The fall armyworm Spodoptera frugiperda is a prime noctuid pest of maize on the American continents where it has remained confined despite occasional interceptions by European quarantine services in recent years. The pest has currently become a new invasive species in West and Central Africa where outbreaks were recorded for the first time in early 2016. The presence of at least two distinct haplotypes within samples collected on maize in Nigeria and São Tomé suggests multiple introductions into the African continent. Implications of this new threat to the maize crop in tropical Africa are briefly discussed. PMID:27788251

  12. High blood pressure and associated risk factors as indicator of preclinical hypertension in rural West Africa

    PubMed Central

    Jobe, Modou; Agbla, Schadrac C.; Prentice, Andrew M.; Hennig, Branwen J.

    2017-01-01

    Abstract Hypertension is fast becoming a major public health problem across sub-Saharan Africa. We sought to determine the prevalence of high blood pressure (BP) and associated risk factors as indicator of preclinical hypertension in a rural Gambian population. We analyzed data on 6160 healthy Gambians cross-sectionally. Attention was given to 5 to <18-year olds (N = 3637), as data from sub-Saharan Africa on this young age group are scarce. High BP was defined as systolic blood pressure (SBP) above the 95th percentile for age-sex specific height z scores in <18-year olds employing population-specific reference values. Standard high BP categories were applied to ≥18-year olds. In <18-year olds, the multivariable analysis gave an adjusted high BP prevalence ratio of 0.95 (95% confidence interval [CI] 0.92–0.98; P = 0.002) for age and 1.13 (95% CI 1.06–1.19; P < 0.0001) for weight-for-height z score (zWT-HT); sex and hemoglobin were not shown to affect high BP. In adults age 1.05 (95% CI 1.04–1.05; P < 0.0001), body mass index z score 1.28 (95% CI 1.16–1.40; P < 0.0001), hemoglobin 0.90 (95% CI 0.85–0.96; P < 0.0001) and high fasting glucose 2.60 (95% CI 2.02–3.36; P < 0.0001, though the number was very low) were confirmed as risk factors for high BP prevalence; sex was not associated. The reported high BP prevalence and associated risk factors in adults are comparable to other studies conducted in the region. The observed high BP prevalence of 8.2% (95% CI 7.4–9.2) in our generally lean young Gambians (<18 years) is alarming, given that high BP tracks from childhood to adulthood. Hence there is an urgent need for further investigation into risk factors of pediatric high BP/hypertension even in rural African settings. PMID:28353557

  13. An investigation of MAGSAT and complementary data emphasizing precambrian shields and adjacent areas of West Africa and South America

    NASA Technical Reports Server (NTRS)

    Hastings, D. A. (Principal Investigator)

    1981-01-01

    Accomplishments with regard to the mapping and analysis of MAGSAT data for the investigation of correlations between the magnetic field characteristics of South American and African shields are reported. Significant results in the interpretation of the global total-field anomalies and the anomaly patterns of Africa and South America are discussed. The central position of the Brazilian shield tends to form a negative total-field anomaly, consistent with findings for shields in equatorial Africa. Sedimentary sequences in the Amazon basin and in the Rio de Janeiro-Sao Paolo areas exhibit positive anomalies, also consistent with equatorial Africa. Results for the Caribbean Sea and Guyana regions are also described.

  14. An investigation of MAGSAT and complementary data emphasizing precambrian shields and adjacent areas of West Africa and South America

    NASA Technical Reports Server (NTRS)

    Hastings, D. A. (Principal Investigator)

    1982-01-01

    The problems associated with the use of an interactive magnetic modeling program are reported and a publication summarizing the MAGSAT anomaly results for Africa and the possible tectonic associations of these anomalies is provided. An overview of the MAGSAT scalar anomaly map for Africa suggested a correlation of MAGSAT anomalies with major crustal blocks of uplift or depression and different degrees of regional metamorphism. The strongest MAGSAT anomalies in Africa are closely correlated spatially with major tectonic features. Results indicate that the Bangui anomaly may be caused by a central old Precambrian shield, flanked to the north and south by two relatively young sedimentary basins.

  15. Solid waste characterization in Ketao, a rural town in Togo, West Africa.

    PubMed

    Edjabou, Maklawe Essonanawe; Møller, Jacob; Christensen, Thomas H

    2012-07-01

    In Africa the majority of solid waste data is for big cities. Small and rural towns are generally neglected and waste data from these areas are often unavailable, which makes planning a proper solid waste management difficult. This paper presents the results from two waste characterization projects conducted in Kétao, a rural town in Togo during the rainy season and the dry season in 2010. The seasonal variation has a significant impact on the waste stream. The household waste generation rate was estimated at 0.22 kg person(-1) day(-1) in the dry season and 0.42 in the rainy season. Likewise, the waste moisture content was 4% in the dry season while it was 33-63% in the rainy season. The waste consisted mainly of soil and dirt characterized as 'other' (41%), vegetables and putrescibles (38%) and plastic (11%). In addition to these fractions, considerable amounts of material are either recycled or reused locally and do not enter the waste stream. The study suggests that additional recycling is not feasible, but further examination of the degradability of the organic fraction is needed in order to assess whether the residual waste should be composed or landfilled.

  16. Genome-wide and fine-resolution association analysis of malaria in West Africa.

    PubMed

    Jallow, Muminatou; Teo, Yik Ying; Small, Kerrin S; Rockett, Kirk A; Deloukas, Panos; Clark, Taane G; Kivinen, Katja; Bojang, Kalifa A; Conway, David J; Pinder, Margaret; Sirugo, Giorgio; Sisay-Joof, Fatou; Usen, Stanley; Auburn, Sarah; Bumpstead, Suzannah J; Campino, Susana; Coffey, Alison; Dunham, Andrew; Fry, Andrew E; Green, Angela; Gwilliam, Rhian; Hunt, Sarah E; Inouye, Michael; Jeffreys, Anna E; Mendy, Alieu; Palotie, Aarno; Potter, Simon; Ragoussis, Jiannis; Rogers, Jane; Rowlands, Kate; Somaskantharajah, Elilan; Whittaker, Pamela; Widden, Claire; Donnelly, Peter; Howie, Bryan; Marchini, Jonathan; Morris, Andrew; SanJoaquin, Miguel; Achidi, Eric Akum; Agbenyega, Tsiri; Allen, Angela; Amodu, Olukemi; Corran, Patrick; Djimde, Abdoulaye; Dolo, Amagana; Doumbo, Ogobara K; Drakeley, Chris; Dunstan, Sarah; Evans, Jennifer; Farrar, Jeremy; Fernando, Deepika; Hien, Tran Tinh; Horstmann, Rolf D; Ibrahim, Muntaser; Karunaweera, Nadira; Kokwaro, Gilbert; Koram, Kwadwo A; Lemnge, Martha; Makani, Julie; Marsh, Kevin; Michon, Pascal; Modiano, David; Molyneux, Malcolm E; Mueller, Ivo; Parker, Michael; Peshu, Norbert; Plowe, Christopher V; Puijalon, Odile; Reeder, John; Reyburn, Hugh; Riley, Eleanor M; Sakuntabhai, Anavaj; Singhasivanon, Pratap; Sirima, Sodiomon; Tall, Adama; Taylor, Terrie E; Thera, Mahamadou; Troye-Blomberg, Marita; Williams, Thomas N; Wilson, Michael; Kwiatkowski, Dominic P

    2009-06-01

    We report a genome-wide association (GWA) study of severe malaria in The Gambia. The initial GWA scan included 2,500 children genotyped on the Affymetrix 500K GeneChip, and a replication study included 3,400 children. We used this to examine the performance of GWA methods in Africa. We found considerable population stratification, and also that signals of association at known malaria resistance loci were greatly attenuated owing to weak linkage disequilibrium (LD). To investigate possible solutions to the problem of low LD, we focused on the HbS locus, sequencing this region of the genome in 62 Gambian individuals and then using these data to conduct multipoint imputation in the GWA samples. This increased the signal of association, from P = 4 × 10(-7) to P = 4 × 10(-14), with the peak of the signal located precisely at the HbS causal variant. Our findings provide proof of principle that fine-resolution multipoint imputation, based on population-specific sequencing data, can substantially boost authentic GWA signals and enable fine mapping of causal variants in African populations.

  17. Crustal structure of Nigeria and Southern Ghana, West Africa from P-wave receiver functions

    NASA Astrophysics Data System (ADS)

    Akpan, Ofonime; Nyblade, Andrew; Okereke, Chiedu; Oden, Michael; Emry, Erica; Julià, Jordi

    2016-04-01

    We report new estimates of crustal thickness (Moho depth), Poisson's ratio and shear-wave velocities for eleven broadband seismological stations in Nigeria and Ghana. Data used for this study came from teleseismic earthquakes recorded at epicentral distances between 30° and 95° and with moment magnitudes greater than or equal to 5.5. P-wave receiver functions were modeled using the Moho Ps arrival times, H-k stacking, and joint inversion of receiver functions and Rayleigh wave group velocities. The average crustal thickness of the stations in the Neoproterozoic basement complex of Nigeria is 36 km, and 23 km for the stations in the Cretaceous Benue Trough. The crustal structure of the Paleoproterozoic Birimian Terrain, and Neoproterozoic Dahomeyan Terrain and Togo Structural Unit in southern Ghana is similar, with an average Moho depth of 44 km. Poisson's ratios for all the stations range from 0.24 to 0.26, indicating a bulk felsic to intermediate crustal composition. The crustal structure of the basement complex in Nigeria is similar to the average crustal structure of Neoproterozoic terrains in other parts of Africa, but the two Neoproterozoic terrains in southern Ghana have a thicker crust with a thick mafic lower crust, ranging in thickness from 12 to 17 km. Both the thicker crust and thick mafic lower crustal section are consistent with many Precambrian suture zones, and thus we suggest that both features are relict from the collisional event during the formation of Gondwana.

  18. Associations between Mycobacterium ulcerans and aquatic plant communities of West Africa: implications for Buruli ulcer disease.

    PubMed

    McIntosh, Mollie; Williamson, Heather; Benbow, M Eric; Kimbirauskas, Ryan; Quaye, Charles; Boakye, Daniel; Small, Pamela; Merritt, Richard

    2014-06-01

    Numerous studies have associated Buruli ulcer (BU) disease with disturbed aquatic habitats; however, the natural reservoir, distribution, and transmission of the pathogen, Mycobacterium ulcerans, remain unknown. To better understand the role of aquatic plants in the ecology of this disease, a large-scale survey was conducted in waterbodies of variable flow throughout three regions of Ghana, Africa. Our objectives were to characterize plant communities and identify potential relationships with M. ulcerans and other mycolactone-producing mycobacteria (MPM). Waterbodies with M. ulcerans had significantly different aquatic plant communities, with submerged terrestrial plants identified as indicators of M. ulcerans presence. Mycobacterium ulcerans and MPM were detected on 14 plant taxa in emergent zones from both lotic and lentic waterbodies in endemic regions; however, M. ulcerans was not detected in the non-endemic Volta region. These findings support the hypothesis that plants provide substrate for M. ulcerans colonization and could act as potential indicators for disease risk. These findings also suggest that M. ulcerans is a widespread environmental bacteria species, but that it is absent or reduced in regions of low disease incidence. A better understanding is needed regarding the mechanistic associations among aquatic plants and M. ulcerans for identifying the mode of transmission of BU disease.

  19. Improving Malaria Control in West Africa: Interruption of Transmission as a Paradigm Shift

    PubMed Central

    Doumbia, Seydou O.; Ndiaye, Daouda; Koita, Ousmane A.; Diakité, Mahamadou; Nwakanma, Davis; Coulibaly, Mamadou; Traoré, Sekou F.; Keating, Joseph; Milner, Danny A.; Ndiaye, Jean-Louis; Sene, Papa Diogoye; Ahouidi, Ambroise; Dieye, Tandakha N.; Gaye, Oumar; Okebe, Joseph; Ceesay, Serign J.; Ngwa, Alfred; Oriero, Eniyou C.; Konaté, Lassana; Sy, Ngayo; Jawara, Musa; Faye, Ousmane; Kéita, Moussa; Cissé, Moussa; Sogoba, Nafomon; Poudiougou, Belco; Diawara, Sory; Sangaré, Lansana; Coulibaly, Tinzana; Seck, Ibrahima; Abubakar, Ismaela; Gomis, Jules; Mather, Frances J.; Sissako, Aliou; Diarra, Ayouba; Kandeh, Balla; Whalen, Christopher; Moyer, Brian; Nnedu, Obinna; Thiero, Oumar; Bei, Amy K.; Daniels, Rachel; Miura, Kazutoyo; Long, Carole A.; Fairhurst, Rick M.; Duraisingh, Manoj; Muskavitch, Marc A.T.; D’Alessandro, Umberto; Conway, David J.; Volkman, Sarah K.; Valim, Clarissa; Wirth, Dyann F.; Krogstad, Donald J.

    2011-01-01

    With the paradigm shift from the reduction of morbidity and mortality to the interruption of transmission, the focus of malaria control broadens from symptomatic infections in children ≤ 5 years of age to include asymptomatic infections in older children and adults. In addition, as control efforts intensify and the number of interventions increases, there will be decreases in prevalence, incidence and transmission with additional decreases in morbidity and mortality. Expected secondary consequences of these changes include upward shifts in the peak ages for infection (parasitemia) and disease, increases in the ages for acquisition of antiparasite humoral and cellular immune responses and increases in false-negative blood smears and rapid diagnostic tests. Strategies to monitor these changes must include: 1] studies of the entire population (that are not restricted to children ≤ 5 or ≤ 10 years of age), 2] study sites in both cities and rural areas (because of increasing urbanization across sub-Saharan Africa) and 3] innovative strategies for surveillance as the prevalence of infection decreases and the frequency of false-negative smears and rapid diagnostic tests increases. PMID:22142790

  20. Neogene desertification of Africa

    NASA Astrophysics Data System (ADS)

    Senut, Brigitte; Pickford, Martin; Ségalen, Loïc

    2009-08-01

    Throughout the Neogene, the faunas and floras in Africa recorded global climatic changes. We present an overview of Neogene desertification in Africa by tracing stable isotopes in eggshells and mammalian enamel, by faunal (changes in hypsodonty, etc.) and floral changes in sequences at the latitudinal extremities of the continent and the equator. This work reveals that desertification started in the southwest ca 17-16 Ma, much earlier than the region of the present-day Sahara (ca 8-7 Ma) and long before the deserts in East Africa (Plio-Pleistocene). A consequence of this history is that animals and plants inhabiting the South of the continent had a long period of time in which to adapt to arid, unstable climatic conditions. When parts of East Africa became arid during the Late Miocene and Plio-Pleistocene, several of these lineages expanded northwards and occupied developing arid niches before local lineages could adapt. Several of the latter became extinct, while others withdrew westwards as the tropical forest diminished in extent. It is proposed that the history of desertification in Africa was related to that of the polar ice caps (Antarctic, Arctic).

  1. An overview of the socio-cultural and psychiatric aspects of women's reproductive health in West Africa.

    PubMed

    Aina, O F

    2007-09-01

    The challenges associated with women reproductive health in West African sub region have over the years become a source of concern to relevant world bodies such as WHO, UNFPA, World Bank etc. Some of these challenges include Infertility, Family Planning and Female Genital Mutilation (FGM). However, of greater concern is the scourge of Sexually Transmitted Diseases (STDs) most especially HIV/ AIDS and the unacceptably high maternal mortality in the sub region where Nigeria alone accounts for the highest percentage (10%) of the global 60,000 maternal deaths annually. Significant psychiatric complications such as anxiety and depression are associated with menstruation and menopause. However, the postpartum period is the most vulnerable with significant proportion of women developing such psychopathologies as Puerperal (maternity) blues, Postpartum Depression (PPD) and Acute Organic Brain Syndrome. Sociocultural factors, the dearth of psychiatrists in West Africa coupled with the poor or non-recognition of the psychiatric complications by the obstetric staff have not allowed enough clinical attention to be paid to these problems. It is thus advocated that improvement in the maternal and child health care component of the primary health care (PHC) services will go a long way to attenuate the psychiatric complications associated with childbirth.

  2. Evaluation of remotely sensed DMP product using multi-year field measurements of biomass in West Africa

    NASA Astrophysics Data System (ADS)

    Nutini, Francesco; Stroppiana, Daniela; Boschetti, Mirco; Brivio, Pietro A.; Bartholome, Etienne; Beye, Gora

    2011-11-01

    The Sahelian belt of West Africa is a region characterized by wide climate variations, which can in turn affect the survival of local populations especially in rangeland, as happened during the dramatic food crisis in the 70-80s caused by severe drought. This work has been carried out in the framework of the EU FP7 Geoland2 project as a contribution to the ECOWAS component (Economic Community Of West African States) of the AMESD (African Monitoring of the Environment for Sustainable Development) programme with the purpose of establishing the reliability of Dry Matter Productivity (DMP) developed by Flemish Institute for Technological Research (VITO), a spatial estimation of dry matter (DM) obtained from remotely sensed data. DMP can be of great help in monitoring savanna pasturelands in a region characterized by food insecurity and a significant variability of biomass production, linked to climate variations, which can in turn affect the survival of local populations. The evaluation of DMP was carried out thanks to the Centre de Suivi Ecologique (CSE) and Action Contre la Fame (ACF), the partners who provided the field biomass measurements. The paper shows the correlation of DMP with field measurements of herbaceous biomass, and discusses the differences among the different sites where ground data were collected. The analysis of other environmental variables (land cover, rainfall), which can be influential on rangeland biomass production, is presented in order to better explain the variance of field measurements among the different years.

  3. Re-assessment of the northern Guinean "Koubia-Lessere unconformity" (KLU): Consequences on the geological correlations throughout West Africa

    NASA Astrophysics Data System (ADS)

    Villeneuve, Michel; Theveniaut, Hervé; Ndiaye, Papa Moussa; Retière, Sylvain

    2014-09-01

    New radiometric data from recent cartographic projects (2007, 2010) lead to a re-interpretation of the "Koubia-Lessere Unconformity" (KLU). This unconformity is evidenced in the Bassaride Ranges (northern Guinea) and in two western inliers (Tominé and Kemberra). The KLU was previously correlated with the main unconformity (Jbeliat unconformity [JU]) separating the lower "super group 1" from the middle "super group 2" of the large Taoudeni basin. Consequently, the brecciated level (partly glaciogenic) that underlines the "KLU" was correlated with the "tillitic" level located at the base of the super group 2. The latter is linked to the worldwide "Marinhoan" glacial event (650-635 Ma). However, 32 recently published U/Pb age data on detrital or new formed zircons show clearly that the Bassarides groups (ante KLU), deformed and slightly metamorphosed by the Panafrican-II orogen, belong to the super group 2 of the Taoudeni basin. Consequently, the overlying "Koubia-Lessere unconformity" (KLU) cannot be linked to the "Jbeliats unconformity" (JU) that separates the super groups 1 and 2 in the Taoudeni basin. The KLU is younger than the Panafrican-II orogen and probably younger than the last volcanic basaltic flows (492 Ma) outcropping in the Bassaride belt. Consequently, the glaciogenic levels that outcrop in the KLU should be distinguished from the numerous "Marinhoan" glacial levels of West Africa. This new KLU interpretation implies some important changes in the stratigraphic correlations and interpretations all over the West African domain.

  4. [Ebola virus disease in West Africa and Germany : clinical presentation, management and practical experience with medevacuated patients in Germany].

    PubMed

    Schmiedel, Stefan; Kreuels, B

    2015-07-01

    Ebolaviruses are the causative pathogens of a severe form of viral haemorrhagic fever with cytokine induced shock and multi-organ failure and a high case fatality rate in humans (50-90 %, more than 70 % in the beginning of the current outbreak), designated Ebola haemorrhagic fever or Ebola virus disease (EVD). Ebola is endemic in regions of Central and West Africa. Ebolavirus Zaire (EBOV) is the most aggressive Ebola virus species and is causing the current epidemic. Currently, beginning in late 2013, an unprecedented epidemic with several thousand cases and deaths (as per WHO report 24.12.2014: 19,497 documented cases, 7588 death, 2352 cases in past 3 weeks) is unfolding in Guinea, Liberia and Sierra Leone, and spreading to other countries in Africa, Europe and the USA, where isolated cases have occurred. Ebola transmission occurs exclusively through direct contact with body fluids through mucosal surfaces, skin abrasions, or by parenteral introduction-an aerolised transmission has not been reported so far. Infections in healthcare personnel have not only occurred after needle stick injuries but also after unsafe doffing procedures of personal protection equipment (PPE). The protection of healthcare personnel caring for Ebola patients, therefore, requires that high standards in the use of PPE are mandatory. In high-income countries the management and treatment of EVD patients in specialized centres is recommended. Using negative pressure rooms and positive pressure suits may provide additional safety. Due to the high degree of training and monitoring needed to prevent occupational risks, treatment of EVD patients in non-specialized hospitals should not take place.

  5. Spatial and temporal dynamics of superspreading events in the 2014–2015 West Africa Ebola epidemic

    PubMed Central

    Lau, Max S. Y.; Dalziel, Benjamin Douglas; Funk, Sebastian; McClelland, Amanda; Tiffany, Amanda; Riley, Steven; Metcalf, C. Jessica E.; Grenfell, Bryan T.

    2017-01-01

    The unprecedented scale of the Ebola outbreak in Western Africa (2014–2015) has prompted an explosion of efforts to understand the transmission dynamics of the virus and to analyze the performance of possible containment strategies. Models have focused primarily on the reproductive numbers of the disease that represent the average number of secondary infections produced by a random infectious individual. However, these population-level estimates may conflate important systematic variation in the number of cases generated by infected individuals, particularly found in spatially localized transmission and superspreading events. Although superspreading features prominently in first-hand narratives of Ebola transmission, its dynamics have not been systematically characterized, hindering refinements of future epidemic predictions and explorations of targeted interventions. We used Bayesian model inference to integrate individual-level spatial information with other epidemiological data of community-based (undetected within clinical-care systems) cases and to explicitly infer distribution of the cases generated by each infected individual. Our results show that superspreaders play a key role in sustaining onward transmission of the epidemic, and they are responsible for a significant proportion (∼61%) of the infections. Our results also suggest age as a key demographic predictor for superspreading. We also show that community-based cases may have progressed more rapidly than those notified within clinical-care systems, and most transmission events occurred in a relatively short distance (with median value of 2.51 km). Our results stress the importance of characterizing superspreading of Ebola, enhance our current understanding of its spatiotemporal dynamics, and highlight the potential importance of targeted control measures. PMID:28193880

  6. Disaggregating Tropical Disease Prevalence by Climatic and Vegetative Zones within Tropical West Africa

    PubMed Central

    Beckley, Carl S.; Shaban, Salisu; Palmer, Guy H.; Hudak, Andrew T.; Noh, Susan M.; Futse, James E.

    2016-01-01

    Tropical infectious disease prevalence is dependent on many socio-cultural determinants. However, rainfall and temperature frequently underlie overall prevalence, particularly for vector-borne diseases. As a result these diseases have increased prevalence in tropical as compared to temperate regions. Specific to tropical Africa, the tendency to incorrectly infer that tropical diseases are uniformly prevalent has been partially overcome with solid epidemiologic data. This finer resolution data is important in multiple contexts, including understanding risk, predictive value in disease diagnosis, and population immunity. We hypothesized that within the context of a tropical climate, vector-borne pathogen prevalence would significantly differ according to zonal differences in rainfall, temperature, relative humidity and vegetation condition. We then determined if these environmental data were predictive of pathogen prevalence. First we determined the prevalence of three major pathogens of cattle, Anaplasma marginale, Babesia bigemina and Theileria spp, in the three vegetation zones where cattle are predominantly raised in Ghana: Guinea savannah, semi-deciduous forest, and coastal savannah. The prevalence of A. marginale was 63%, 26% for Theileria spp and 2% for B. bigemina. A. marginale and Theileria spp. were significantly more prevalent in the coastal savannah as compared to either the Guinea savanna or the semi-deciduous forest, supporting acceptance of the first hypothesis. To test the predictive power of environmental variables, the data over a three year period were considered in best subsets multiple linear regression models predicting prevalence of each pathogen. Corrected Akaike Information Criteria (AICc) were assigned to the alternative models to compare their utility. Competitive models for each response were averaged using AICc weights. Rainfall was most predictive of pathogen prevalence, and EVI also contributed to A. marginale and B. bigemina prevalence

  7. Alu insertions in the Iberian Peninsula and north west Africa--genetic boundaries or melting pot?

    PubMed

    González-Pérez, Emili; Via, Marc; Esteban, Esther; López-Alomar, Antoni; Mazieres, Stéphane; Harich, Nourdin; Kandil, Mostafa; Dugoujon, Jean-Michel; Moral, Pedro

    2003-12-01

    The Western Mediterranean Basin joins a set of ethnically different populations as Iberians and Basques in the North shore and Berbers and Arab-speakers in the South one. In spite of this differentiation, they have maintained historical contacts since ancient times. The existence of a possible common genetic background (specially for Berbers and Iberians) together with the genetic impact of the Islamic occupation of the Iberian Peninsula during 7 centuries are some of the intriguing anthropological questions that have been studied in this area using several classical and DNA markers. The aim of this work is to present the results on a survey of polymorphic Alu elements in 10 human populations of the Western Mediterranean. Recent Alu subfamilies include a significant number of polymorphic Alu insertions in humans. The polymorphic Alu elements are neutral genetic markers of identical descent with known ancestral states. This fact turns Alu insertions into useful markers for the study of human population genetics. A total number of 14 Alu insertions were analyzed in 5 Iberian populations, 3 Berber groups from North-Western Africa, an Arab-speaker population from Morocco and a sub-Saharan ethnic group from Ivory Coast. The results of this study allow the genetic characterization of Berber populations, which show a certain degree of differentiation from Arab-speaking groups of the same geographic area. Furthermore, a closer genetic distance between South Spain and Moroccan Berbers as compared with other Spanish samples supports a major genetic influx consistent with some (but not all) previous genetic studies on populations from the two shores of the Gibraltar Straits.

  8. Treatment uptake by individuals infected with Plasmodium falciparum in rural Gambia, West Africa.

    PubMed Central

    von Seidlein, Lorenz; Clarke, Sian; Alexander, Neâl; Manneh, Fandingding; Doherty, Tom; Pinder, Margaret; Walraven, Gijs; Greenwood, Brian

    2002-01-01

    OBJECTIVE: To find out what proportion of Plasmodium falciparum infections are treated in rural Gambia. METHODS: Subjects from four villages in the Gambia were followed over nine months through visits to village health workers. Monthly cross-sectional malaria surveys measured the prevalence of P. falciparum infection. Linked databases were searched for treatment requests. Treated cases were individuals with parasitaemia who requested treatment during narrow or extended periods (14 or 28 days, respectively) before or after a positive blood film was obtained. FINDINGS: Parasite prevalence peaked in November 1998, when 399/653 (61%) individuals had parasitaemia. Parasite prevalence was highest throughout the study in children aged 5-10 years. Although access to treatment was better than in most of sub-Saharan Africa, only 20% of infected individuals sought medical treatment up to 14 days before or after a positive blood film. Within two months of a positive blood film, 199/726 (27%) individuals with parasitaemia requested treatment. Despite easy access to health care, less than half (42%) of those with parasite densities consistent with malaria attacks (5000/ l) requested treatment. High parasite density and infection during October-November were associated with more frequent treatment requests. Self-treatment was infrequent in study villages: in 3/120 (2.5%) households antimalarial drugs had been used in the preceding malaria season. CONCLUSION: Many P. falciparum infections may be untreated because of their subclinical nature. Intermittent presumptive treatment may reduce morbidity and mortality. It is likely that not all untreated infections were asymptomatic. Qualitative research should explore barriers to treatment uptake, to allow educational interventions to be planned. PMID:12471399

  9. Condom use and associated factors among men who have sex with men in Togo, West Africa

    PubMed Central

    Bakai, Tchaa Abalo; Ekouevi, Didier Koumavi; Tchounga, Boris Kévin; Balestre, Eric; Afanvi, Kossivi Agbélénko; Goilibe, Kariyiare Benjamin; Kassankogno, Yao; Pitche, Vincent Palokinam

    2016-01-01

    Introduction In 2011, the prevalence of HIV among men who have sex with men (MSM) in Togo was estimated at 19.6% compared to 3.4% in the general population. This study aimed to describe condom use and associated factors among MSM in Togo. Methods In 2011, a cross-sectional survey was conducted using the snowball sampling method among MSM in Togo. This study enrolled MSM aged 18 years and above who reported having sexual contact with other men within the last 30 days. A standardized survey form was used for data collection, and multivariate analyses were performed. Results A total of 724 MSM were included in this study. The median age was 25 years [22-28], 90.3% had at least a secondary school level. The sexual practices during the last sexual encounter with another man included: insertive anal sex (62.2%), receptive anal sex (56.6%), oral sex (33.8%) and oral-anal sex (8.6%). A condom was used during the last insertive and receptive anal encounters in 78.4% and 81.2% of the time, respectively. In multivariate analysis, condom use was positively associated with previous participation in HIV/STD prevention activities (aOR=1.72; 95% CI=[1.09-2.71]), with the consideration of the last sexual partner as a casual one (aOR=1.87; 95% CI=[1.24-2.82]) and with having at least a secondary school level (aOR=2.40; 95% CI=[1.22-4.69]). Conclusion One out of five MSM did not use a condom during the last anal encounter with another man. HIV prevention programs in Africa should develop specific interventions targeting MSM to reduce the incidence of HIV in this hidden population. PMID:27279945

  10. Comparison of DNA fingerprint patterns of isolates of Mycobacterium africanum from east and west Africa.

    PubMed Central

    Haas, W H; Bretzel, G; Amthor, B; Schilke, K; Krommes, G; Rüsch-Gerdes, S; Sticht-Groh, V; Bremer, H J

    1997-01-01

    Mycobacterium africanum is a pathogen found in tuberculosis patients in certain parts of Africa and is a member of the Mycobacterium tuberculosis complex. Biochemically, strains of M. africanum exhibit a high degree of variability, with some tendency to cluster according to their geographical origin. To investigate whether this phenotypic variability is reflected at the genetic level, we performed DNA fingerprint analysis of strains isolated from patients with pulmonary tuberculosis in Uganda and Sierra Leone. IS6110 DNA fingerprinting was carried out by the mixed-linker PCR method. A total of 138 strains of M. africanum were analyzed: 42 isolates from Uganda and 96 isolates from Sierra Leone. With few exceptions, the resulting DNA fingerprint patterns grouped together according to their country of origin. A striking lack of variability of DNA fingerprints was found for strains from Sierra Leone, where 70 of 96 isolates (61.5%) fell into clusters. The two largest clusters accounted for 41.7% of all isolates and differed by only one band, as confirmed by standard DNA fingerprinting. In contrast, only two clusters (7.1%) with two and three isolates, respectively, were found for M. africanum isolates collected in Uganda, and three of the DNA fingerprints contained fewer than seven bands. Strains of M. tuberculosis collected and processed during the same time period were highly variable in both countries. Our results support the concept of geographically defined subtypes of M. africanum. In addition, they demonstrate that natural geographic differences in the variability of IS6110 DNA fingerprints within the M. tuberculosis complex must be considered if this technique is used for epidemiologic studies. PMID:9041408

  11. Disaggregating Tropical Disease Prevalence by Climatic and Vegetative Zones within Tropical West Africa.

    PubMed

    Beckley, Carl S; Shaban, Salisu; Palmer, Guy H; Hudak, Andrew T; Noh, Susan M; Futse, James E

    2016-01-01

    Tropical infectious disease prevalence is dependent on many socio-cultural determinants. However, rainfall and temperature frequently underlie overall prevalence, particularly for vector-borne diseases. As a result these diseases have increased prevalence in tropical as compared to temperate regions. Specific to tropical Africa, the tendency to incorrectly infer that tropical diseases are uniformly prevalent has been partially overcome with solid epidemiologic data. This finer resolution data is important in multiple contexts, including understanding risk, predictive value in disease diagnosis, and population immunity. We hypothesized that within the context of a tropical climate, vector-borne pathogen prevalence would significantly differ according to zonal differences in rainfall, temperature, relative humidity and vegetation condition. We then determined if these environmental data were predictive of pathogen prevalence. First we determined the prevalence of three major pathogens of cattle, Anaplasma marginale, Babesia bigemina and Theileria spp, in the three vegetation zones where cattle are predominantly raised in Ghana: Guinea savannah, semi-deciduous forest, and coastal savannah. The prevalence of A. marginale was 63%, 26% for Theileria spp and 2% for B. bigemina. A. marginale and Theileria spp. were significantly more prevalent in the coastal savannah as compared to either the Guinea savanna or the semi-deciduous forest, supporting acceptance of the first hypothesis. To test the predictive power of environmental variables, the data over a three year period were considered in best subsets multiple linear regression models predicting prevalence of each pathogen. Corrected Akaike Information Criteria (AICc) were assigned to the alternative models to compare their utility. Competitive models for each response were averaged using AICc weights. Rainfall was most predictive of pathogen prevalence, and EVI also contributed to A. marginale and B. bigemina prevalence

  12. Spatial and temporal dynamics of superspreading events in the 2014-2015 West Africa Ebola epidemic.

    PubMed

    Lau, Max S Y; Dalziel, Benjamin Douglas; Funk, Sebastian; McClelland, Amanda; Tiffany, Amanda; Riley, Steven; Metcalf, C Jessica E; Grenfell, Bryan T

    2017-02-28

    The unprecedented scale of the Ebola outbreak in Western Africa (2014-2015) has prompted an explosion of efforts to understand the transmission dynamics of the virus and to analyze the performance of possible containment strategies. Models have focused primarily on the reproductive numbers of the disease that represent the average number of secondary infections produced by a random infectious individual. However, these population-level estimates may conflate important systematic variation in the number of cases generated by infected individuals, particularly found in spatially localized transmission and superspreading events. Although superspreading features prominently in first-hand narratives of Ebola transmission, its dynamics have not been systematically characterized, hindering refinements of future epidemic predictions and explorations of targeted interventions. We used Bayesian model inference to integrate individual-level spatial information with other epidemiological data of community-based (undetected within clinical-care systems) cases and to explicitly infer distribution of the cases generated by each infected individual. Our results show that superspreaders play a key role in sustaining onward transmission of the epidemic, and they are responsible for a significant proportion ([Formula: see text]61%) of the infections. Our results also suggest age as a key demographic predictor for superspreading. We also show that community-based cases may have progressed more rapidly than those notified within clinical-care systems, and most transmission events occurred in a relatively short distance (with median value of 2.51 km). Our results stress the importance of characterizing superspreading of Ebola, enhance our current understanding of its spatiotemporal dynamics, and highlight the potential importance of targeted control measures.

  13. High Genetic Diversity of Newcastle Disease Virus in Poultry in West and Central Africa: Cocirculation of Genotype XIV and Newly Defined Genotypes XVII and XVIII

    PubMed Central

    Snoeck, Chantal J.; Owoade, Ademola A.; Couacy-Hymann, Emmanuel; Alkali, Bello R.; Okwen, Mbah P.; Adeyanju, Adeniyi T.; Komoyo, Giscard F.; Nakouné, Emmanuel; Le Faou, Alain

    2013-01-01

    Despite rampant Newcastle disease virus (NDV) outbreaks in Africa for decades, the information about the genetic characteristics of the virulent strains circulating in West and Central Africa is still scarce. In this study, 96 complete NDV fusion gene sequences were obtained from poultry sampled in Cameroon, Central African Republic, Côte d'Ivoire, and Nigeria between 2006 and 2011. Based on rational criteria recently proposed for the classification of NDV strains into classes, genotypes, and subgenotypes, we revisited the classification of virulent strains, in particular those from West and Central Africa, leading to their grouping into genotype XIV and newly defined genotypes XVII and XVIII, each with two subgenotypes. Phylogenetic analyses revealed that several (sub)genotypes are found in almost every country. In Cameroon, most strains were related to vaccine strains, but a single genotype XVII strain was also found. Only three highly similar genotype XVII strains were detected in Central African Republic. Subgenotypes XVIIa, XVIIIa, and XVIIIb cocirculated in Côte d'Ivoire, while subgenotypes XIVa, XIVb, XVIIa, XVIIb, and XVIIIb were found in Nigeria. While these genotypes are so far geographically restricted, local and international trade of domestic and exotic birds may lead to their spread beyond West and Central Africa. A high genetic diversity, mutations in important neutralizing epitopes paired with suboptimal vaccination, various levels of clinical responses of poultry and wild birds to virulent strains, strains with new cleavage sites, and other genetic modifications found in these genotypes tend to undermine and complicate NDV management in Africa. PMID:23658271

  14. WASCAL - West African Science Service Center on Climate Change and Adapted Land Use Regional Climate Simulations and Land-Atmosphere Simulations for West Africa at DKRZ and elsewhere

    NASA Astrophysics Data System (ADS)

    Hamann, Ilse; Arnault, Joel; Bliefernicht, Jan; Klein, Cornelia; Heinzeller, Dominikus; Kunstmann, Harald

    2014-05-01

    Changing climate and hydro-meteorological boundary conditions are among the most severe challenges to Africa in the 21st century. In particular West Africa faces an urgent need to develop effective adaptation and mitigation strategies to cope with negative impacts on humans and environment due to climate change, increased hydro-meteorological variability and land use changes. To help meet these challenges, the German Federal Ministry of Education and Research (BMBF) started an initiative with institutions in Germany and West African countries to establish together a West African Science Service Center on Climate Change and Adapted Land Use (WASCAL). This activity is accompanied by an establishment of trans-boundary observation networks, an interdisciplinary core research program and graduate research programs on climate change and related issues for strengthening the analytical capabilities of the Science Service Center. A key research activity of the WASCAL Competence Center is the provision of regional climate simulations in a fine spatio-temporal resolution for the core research sites of WASCAL for the present and the near future. The climate information is needed for subsequent local climate impact studies in agriculture, water resources and further socio-economic sectors. The simulation experiments are performed using regional climate models such as COSMO-CLM, RegCM and WRF and statistical techniques for a further refinement of the projections. The core research sites of WASCAL are located in the Sudanian Savannah belt in Northern Ghana, Southern Burkina Faso and Northern Benin. The climate in this region is semi-arid with six rainy months. Due to the strong population growth in West Africa, many areas of the Sudanian Savannah have been already converted to farmland since the majority of the people are living directly or indirectly from the income produced in agriculture. The simulation experiments of the Competence Center and the Core Research Program are

  15. Chemical and aerosol characterisation of the troposphere over West Africa during the monsoon period as part of AMMA

    NASA Astrophysics Data System (ADS)

    Reeves, C. E.; Formenti, P.; Afif, C.; Ancellet, G.; Attie, J.-L.; Bechara, J.; Borbon, A.; Cairo, F.; Coe, H.; Crumeyrolle, S.; Fierli, F.; Flamant, C.; Gomes, L.; Hamburger, T.; Lambert, C.; Law, K. S.; Mari, C.; Matsuki, A.; Methven, J.; Mills, G. P.; Minikin, A.; Murphy, J. G.; Nielsen, J. K.; Oram, D. E.; Parker, D. J.; Richter, A.; Schlager, H.; Schwarzenboeck, A.; Thouret, V.

    2010-03-01

    During June, July and August 2006 five aircraft took part in a campaign over West Africa to observe the aerosol content and chemical composition of the troposphere and lower stratosphere as part of the African Monsoon Multidisciplinary Analysis (AMMA) project. These are the first such measurements in this region during the monsoon period. In addition to providing an overview of the tropospheric composition, this paper provides a description of the measurement strategy (flights performed, instrumental payloads, wing-tip to wing-tip comparisons) and points to some of the important findings discussed in more detailed in other papers in this special issue. The ozone data exhibits an "S" shaped vertical profile which appears to result from significant losses in the lower troposphere due to rapid deposition to forested areas and photochemical destruction in the moist monsoon air, and convective uplift of O3-poor air to the upper troposphere. This profile is disturbed, particularly in the south of the region, by the intrusions in the lower and middle troposphere of air from the Southern Hemisphere impacted by biomass burning. Comparisons with longer term data sets suggest the impact of these intrusions on West Africa in 2006 was greater than in other recent wet seasons. There is evidence for net photochemical production of ozone in these biomass burning plumes as well as in urban plumes, in particular that from Lagos, convective outflow in the upper troposphere and in boundary layer air affected by nitrogen oxide emissions from recently wetted soils. This latter effect, along with enhanced deposition to the forested areas, contributes to a latitudinal gradient of ozone in the lower troposphere. Biogenic volatile organic compounds are also important in defining the composition both for the boundary layer and upper tropospheric convective outflow. Mineral dust was found to be the most abundant and ubiquitous aerosol type in the atmosphere over Western Africa. Data collected

  16. Chemical and aerosol characterisation of the troposphere over West Africa during the monsoon period as part of AMMA

    NASA Astrophysics Data System (ADS)

    Reeves, C. E.; Formenti, P.; Afif, C.; Ancellet, G.; Attié, J.-L.; Bechara, J.; Borbon, A.; Cairo, F.; Coe, H.; Crumeyrolle, S.; Fierli, F.; Flamant, C.; Gomes, L.; Hamburger, T.; Jambert, C.; Law, K. S.; Mari, C.; Jones, R. L.; Matsuki, A.; Mead, M. I.; Methven, J.; Mills, G. P.; Minikin, A.; Murphy, J. G.; Nielsen, J. K.; Oram, D. E.; Parker, D. J.; Richter, A.; Schlager, H.; Schwarzenboeck, A.; Thouret, V.

    2010-08-01

    During June, July and August 2006 five aircraft took part in a campaign over West Africa to observe the aerosol content and chemical composition of the troposphere and lower stratosphere as part of the African Monsoon Multidisciplinary Analysis (AMMA) project. These are the first such measurements in this region during the monsoon period. In addition to providing an overview of the tropospheric composition, this paper provides a description of the measurement strategy (flights performed, instrumental payloads, wing-tip to wing-tip comparisons) and points to some of the important findings discussed in more detail in other papers in this special issue. The ozone data exhibits an "S" shaped vertical profile which appears to result from significant losses in the lower troposphere due to rapid deposition to forested areas and photochemical destruction in the moist monsoon air, and convective uplift of ozone-poor air to the upper troposphere. This profile is disturbed, particularly in the south of the region, by the intrusions in the lower and middle troposphere of air from the southern hemisphere impacted by biomass burning. Comparisons with longer term data sets suggest the impact of these intrusions on West Africa in 2006 was greater than in other recent wet seasons. There is evidence for net photochemical production of ozone in these biomass burning plumes as well as in urban plumes, in particular that from Lagos, convective outflow in the upper troposphere and in boundary layer air affected by nitrogen oxide emissions from recently wetted soils. This latter effect, along with enhanced deposition to the forested areas, contributes to a latitudinal gradient of ozone in the lower troposphere. Biogenic volatile organic compounds are also important in defining the composition both for the boundary layer and upper tropospheric convective outflow. Mineral dust was found to be the most abundant and ubiquitous aerosol type in the atmosphere over Western Africa. Data

  17. Voodoo in Africa and the United States.

    PubMed

    Golden, K M

    1977-12-01

    The authors states that the practice of hexing is not just a nearly extinct phenomenon of isolated rural communities of the deep south of the United States but is evident in large urban areas in the northeast and west. He describes the psychological mechanisms of voodoo as practiced in West Africa to provide insight into similar practices in the United States.

  18. Processes Underpinning Development and Maintenance of Diversity in Rice in West Africa: Evidence from Combining Morphological and Molecular Markers

    PubMed Central

    Maat, Harro; Richards, Paul; Struik, Paul C.

    2014-01-01

    We assessed the interplay of artificial and natural selection in rice adaptation in low-input farming systems in West Africa. Using 20 morphological traits and 176 molecular markers, 182 farmer varieties of rice (Oryza spp.) from 6 West African countries were characterized. Principal component analysis showed that the four botanical groups (Oryza sativa ssp. indica, O. sativa ssp. japonica, O. glaberrima, and interspecific farmer hybrids) exhibited different patterns of morphological diversity. Regarding O. glaberrima, morphological and molecular data were in greater conformity than for the other botanical groups. A clear difference in morphological features was observed between O. glaberrima rices from the Togo hills and those from the Upper Guinea Coast, and among O. glaberrima rices from the Upper Guinea Coast. For the other three groups such clear patterns were not observed. We argue that this is because genetic diversity is shaped by different environmental and socio-cultural selection pressures. For O. glaberrima, recent socio-cultural selection pressures seemed to restrict genetic diversity while this was not observed for the other botanical groups. We also show that O. glaberrima still plays an important role in the selection practices of farmers and resulting variety development pathways. This is particularly apparent in the case of interspecific farmer hybrids where a relationship was found between pericarp colour, panicle attitude and genetic diversity. Farmer varieties are the product of long and complex trajectories of selection governed by local human agency. In effect, rice varieties have emerged that are adapted to West African farming conditions through genotype × environment × society interactions. The diversity farmers maintain in their rice varieties is understood to be part of a risk-spreading strategy that also facilitates successful and often serendipitous variety innovations. We advocate, therefore, that farmers and farmer varieties should

  19. Dust storm off Western Africa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The impacts of Saharan dust storms reach far beyond Africa. Wind-swept deserts spill airborne dust particles out over the Atlantic Ocean where they can enter trade winds bound for Central and North America and the Caribbean. This Moderate Resolution Imaging Spectroradiometer (MODIS) image shows a dust storm casting an opaque cloud of cloud across the Canary Islands and the Atlantic Ocean west of Africa on June 30, 2002. In general it takes between 5 and 7 days for such an event to cross the Atlantic. The dust has been shown to introduce foreign bacteria and fungi that have damaged reef ecosystems and have even been hypothesized as a cause of increasing occurrences of respiratory complaints in places like Florida, where the amount of Saharan dust reaching the state has been increasing over the past 25 years.

  20. Chinese Public Attention to the Outbreak of Ebola in West Africa: Evidence from the Online Big Data Platform

    PubMed Central

    Liu, Kui; Li, Li; Jiang, Tao; Chen, Bin; Jiang, Zhenggang; Wang, Zhengting; Chen, Yongdi; Jiang, Jianmin; Gu, Hua

    2016-01-01

    Objective: The outbreak of the Ebola epidemic in West Africa in 2014 exerted enormous global public reaction via the Internet and social media. This study aimed to investigate and evaluate the public reaction to Ebola in China and identify the primitive correlation between possible influence factors caused by the outbreak of Ebola in West Africa and Chinese public attention via Internet surveillance. Methods: Baidu Index (BDI) and Sina Micro Index (SMI) were collected from their official websites, and the disease-related data were recorded from the websites of the World Health Organization (WHO), U.S. Centers for Disease Control and Prevention (CDC), and U.S. National Ministries of Health. The average BDI of Internet users in different regions were calculated to identify the public reaction to the Ebola outbreak. Spearman’s rank correlation was used to check the relationship of epidemic trends with BDI and SMI. Additionally, spatio-temporal analysis and autocorrelation analysis were performed to detect the clustered areas with the high attention to the topic of “Ebola”. The related news reports were collected from authoritative websites to identify potential patterns. Results: The BDI and the SMI for “Ebola” showed a similar fluctuating trend with a correlation coefficient = 0.9 (p < 0.05). The average BDI in Beijing, Tibet, and Shanghai was higher than other cities. However, the disease-related indicators did not identify potential correlation with both indices above. A hotspot area was detected in Tibet by local autocorrelation analysis. The most likely cluster identified by spatiotemporal cluster analysis was in the northeast regions of China with the relative risk (RR) of 2.26 (p ≤ 0.01) from 30 July to 14 August in 2014. Qualitative analysis indicated that negative news could lead to a continuous increase of the public’s attention until the appearance of a positive news report. Conclusions: Confronted with the risk of cross-border transmission of

  1. Regional Climate Simulations with COSMO-CLM for West Africa using three different soil-vegetation-atmosphere-transfer (SVAT) module

    NASA Astrophysics Data System (ADS)

    Breil, Marcus; Panitz, Hans-Jürgen

    2014-05-01

    Climate predictions on decadal timescales constitute a new field of research, closing the gap between short-term and seasonal weather predictions and long-term climate projections. Therefore, the Federal Ministry of Education and Research in Germany (BMBF) has recently funded the research program MiKlip (Mittelfristige Klimaprognosen), which aims to create a model system that can provide reliable decadal climate forecasts. Recent studies have suggested that one region with high potential decadal predictability is West Africa. Therefore, the project DEPARTURE (DEcadal Prediction of African Rainfall and ATlantic HURricanE Activity) was established within the MiKlip program to assess the feasibility and the potential added value of regional decadal climate predictions for West Africa. To quantify the potential decadal climate predictability, a multi-model approach with the three different regional climate models REMO, WRF and COSMO-CLM (CCLM) will be realized. The presented research will contribute to DEPARTURE by performing hindcast ensemble simulations with CCLM, driven by global decadal MPI-ESM-LR simulations. Thereby, one focus is on the dynamic soil-vegetation-climate interaction on decadal timescales. Recent studies indicate that there are significant feedbacks between the land-surface and the atmosphere, which might influence the decadal climate variability substantially. To investigate this connection, two different SVATs (Community Land Model (CLM), and VEG3D) will be coupled with the CCLM, replacing TERRA_ML, the standard SVAT implemented in CCLM. Thus, sensitive model parameters shall be identified, whereby the understanding of important processes might be improved. As a first step, TERRA_ML is substituted by VEG3D, a SVAT developed at the IMK-TRO, Karlsruhe, Germany. Compared to TERRA_ML, VEG3D includes an explicit vegetation layer by using a big leaf approach, inducing higher correlations with observations as it has been shown in previous studies. The

  2. Assessing climate change impacts on sorghum and millet yields in the Sudanian and Sahelian savannas of West Africa

    NASA Astrophysics Data System (ADS)

    Sultan, B.; Roudier, P.; Quirion, P.; Alhassane, A.; Muller, B.; Dingkuhn, M.; Ciais, P.; Guimberteau, M.; Traore, S.; Baron, C.

    2013-03-01

    Sub-Saharan West Africa is a vulnerable region where a better quantification and understanding of the impact of climate change on crop yields is urgently needed. Here, we have applied the process-based crop model SARRA-H calibrated and validated over multi-year field trials and surveys at eight contrasting sites in terms of climate and agricultural practices in Senegal, Mali, Burkina Faso and Niger. The model gives a reasonable correlation with observed yields of sorghum and millet under a range of cultivars and traditional crop management practices. We applied the model to more than 7000 simulations of yields of sorghum and millet for 35 stations across West Africa and under very different future climate conditions. We took into account 35 possible climate scenarios by combining precipitation anomalies from -20% to 20% and temperature anomalies from +0 to +6 °C. We found that most of the 35 scenarios (31/35) showed a negative impact on yields, up to -41% for +6 °C/ - 20% rainfall. Moreover, the potential future climate impacts on yields are very different from those recorded in the recent past. This is because of the increasingly adverse role of higher temperatures in reducing crop yields, irrespective of rainfall changes. When warming exceeds +2 °C, negative impacts caused by temperature rise cannot be counteracted by any rainfall change. The probability of a yield reduction appears to be greater in the Sudanian region (southern Senegal, Mali, Burkina Faso, northern Togo and Benin), because of an exacerbated sensitivity to temperature changes compared to the Sahelian region (Niger, Mali, northern parts of Senegal and Burkina Faso), where crop yields are more sensitive to rainfall change. Finally, our simulations show that the photoperiod-sensitive traditional cultivars of millet and sorghum used by local farmers for centuries seem more resilient to future climate conditions than modern cultivars bred for their high yield potential (-28% versus -40% for

  3. Immunologic response in treatment-naïve HIV-2-infected patients: the IeDEA West Africa cohort

    PubMed Central

    Balestre, Eric; Ekouevi, Didier Koumavi; Tchounga, Boris; Eholie, Serge Paul; Messou, Eugène; Sawadogo, Adrien; Thiébaut, Rodolphe; May, Margaret T; Sterne, Jonathan Ac; Dabis, François

    2016-01-01

    Introduction Response to antiretroviral therapy (ART) among individuals infected with HIV-2 is poorly described. We compared the immunological response among patients treated with three nucleoside reverse-transcriptase inhibitors (NRTIs) to boosted protease inhibitor (PI) and unboosted PI-based regimens in West Africa. Methods This prospective cohort study enrolled treatment-naïve HIV-2-infected patients within the International Epidemiological Databases to Evaluate AIDS collaboration in West Africa. We used mixed models to compare the CD4 count response to treatment over 12 months between regimens. Results Of 422 HIV-2-infected patients, 285 (67.5%) were treated with a boosted PI-based regimen, 104 (24.6%) with an unboosted PI-based regimen and 33 (7.8%) with three NRTIs. Treatment groups were comparable with regard to gender (54.5% female) and median age at ART initiation (45.3 years; interquartile range 38.3 to 51.8). Treatment groups differed by clinical stage (21.2%, 16.8% and 17.3% at CDC Stage C or World Health Organization Stage IV for the triple NRTI, boosted PI and unboosted PI groups, respectively, p=0.02), median length of follow-up (12.9, 17.7 and 44.0 months for the triple NRTI, the boosted PI and the unboosted PI groups, respectively, p<0.001) and baseline median CD4 count (192, 173 and 129 cells/µl in the triple NRTI, the boosted PI and the unboosted PI-based regimen groups, respectively, p=0.003). CD4 count recovery at 12 months was higher for patients treated with boosted PI-based regimens than those treated with three NRTIs or with unboosted PI-based regimens (191 cells/µl, 95% CI 142 to 241; 110 cells/µl, 95% CI 29 to 192; 133 cells/µl, 95% CI 80 to 186, respectively, p=0.004). Conclusions In this observational study using African data, boosted PI-containing regimens had better immunological response compared to triple NRTI combinations and unboosted PI-based regimens at 12 months. A randomized clinical trial is still required to determine

  4. Country Energy Profile, South Africa

    SciTech Connect

    1995-08-01

    This country energy profile provides energy and economic information about South Africa. Areas covered include: Economics, demographics, and environment; Energy situation; Energy structure; Energy investment opportunities; Department of Energy (DOE) programs in South Africa; and a listing of International aid to South Africa.

  5. Emergency nursing in South Africa.

    PubMed

    Brysiewicz, Petra; Bruce, Judy

    2008-04-01

    The role of the emergency nurse in South Africa is a challenging one due to a variety of reasons. This article describes the healthcare system of South Africa with particular attention to the emergency medical system as well as the reason why most emergency clients present to the emergency departments. The actual experience of working as an emergency nurse in South Africa is highlighted.

  6. Identification of environmental anomaly hot spots in West Africa from time series of NDVI and rainfall

    NASA Astrophysics Data System (ADS)

    Boschetti, Mirco; Nutini, Francesco; Brivio, Pietro Alessandro; Bartholomé, Etienne; Stroppiana, Daniela; Hoscilo, Agata

    2013-04-01

    Studies of the impact of human activity on vegetation dynamics of the Sahelian belt of Africa have been recently re-invigorated by new scientific findings that highlighted the primary role of climate in the drought crises of the 1970s-1980s. Time series of satellite observations revealed a re-greening of the Sahelian belt that indicates no noteworthy human effect on vegetation dynamics at sub continental scale from the 1980s to late 1990s. However, several regional/local crises related to natural resources occurred in the last decades despite the re-greening thus underlying that more detailed studies are needed. In this study we used time-series (1998-2010) of SPOT-VGT NDVI and FEWS-RFE rainfall estimates to analyse vegetation - rainfall correlation and to map areas of local environmental anomalies where significant vegetation variations (increase/decrease) are not fully explained by seasonal changes of rainfall. Some of these anomalous zones (hot spots) were further analysed with higher resolution images Landsat TM/ETM+ to evaluate the reliability of the identified anomalous behaviour and to provide an interpretation of some example hot spots. The frequency distribution of the hot spots among the land cover classes of the GlobCover map shows that increase in vegetation greenness is mainly located in the more humid southern part and close to inland water bodies where it is likely to be related to the expansion/intensification of irrigated agricultural activities. On the contrary, a decrease in vegetation greenness occurs mainly in the northern part (12°-15°N) in correspondence with herbaceous vegetation covers where pastoral and cropping practices are often critical due to low and very unpredictable rainfall. The results of this study show that even if a general positive re-greening due to increased rainfall is evident for the entire Sahel, some local anomalous hot spots exist and can be explained by human factors such as population growth whose level reaches the

  7. [A collective malarial infestation during a humanitarian mission in west Africa].

    PubMed

    Philippe, J M; Caumon, L; Chouaki, M; Dufraise, S; Rimeize, H; Monchard, F; Cueto, T; Beytout, J; Delort, P

    2002-06-01

    travelers and drivers planning a trip to Sub-Saharan Africa to take with them anti-vectorial protective gear. Finally, the observation of these cases indicates once more the difficulty in France of establishing a proper diagnosis in face of malaria. Health personnel must systematically call to mind malaria in face of thrombopenia or fever following a sojourn in an endemic area even when chemoprophylaxis has been correctly followed.

  8. Factors associated with antenatal mental disorder in West Africa: A cross-sectional survey

    PubMed Central

    2011-01-01

    Background Maternal mental illness is likely to have a profound impact in less developed parts of the world. A mother experiencing mental illness in a low income setting is at risk of providing sub-optimal care for her offspring which can have grave consequences in an environment where poverty, overcrowding, poor sanitation, malnutrition, tropical diseases and a lack of appropriate medical services may be pronounced. Given the profound consequences of antenatal and postnatal mental illness on maternal mental health, foetal wellbeing and childhood growth and development the factors associated with mental illness in a Sub-Saharan setting merit clarification and investigation. Methods A prospective survey design was conducted in Lagos. Self reporting questionnaire 20 items - SRQ20 - assessed the presence of mental illness. The WHO Multi-country Study on Women's Health and Domestic Violence Questions assessed women's exposure to violence. Numerous variables potentially associated with mental illness including maternal socio-economic factors, maternal characteristics, obstetric variables and the characteristics of previous children were recorded. Direct logistic regression was performed to assess the impact of a number of variables on the likelihood of presence of mental disorder in the population. Results 189 women were surveyed. 7% met the criteria for experiencing a common mental disorder according to their score on the SRQ-20. Of variables examined only the number of female children and the presence of inter personal violence predicted being a case of mental illness (OR = 3.400; 95%CI = 1.374 - 8.414 and OR = 5.676; 95%CI = 1.251 - 25.757 respectively). Conclusions Rates of mental disorder found in our study were lower than those previously observed internationally and in Africa, perhaps reflecting stigma about disclosing symptoms. The predictive nature of violence on mental disorder is in keeping with international evidence. Our study demonstrated that exposure to

  9. The Epi Info Viral Hemorrhagic Fever (VHF) Application: A Resource for Outbreak Data Management and Contact Tracing in the 2014-2016 West Africa Ebola Epidemic.

    PubMed

    Schafer, Ilana J; Knudsen, Erik; McNamara, Lucy A; Agnihotri, Sachin; Rollin, Pierre E; Islam, Asad

    2016-10-15

    The Epi Info Viral Hemorrhagic Fever application (Epi Info VHF) was developed in response to challenges managing outbreak data during four 2012 filovirus outbreaks. Development goals included combining case and contact data in a relational database, facilitating data-driven contact tracing, and improving outbreak data consistency and use. The application was first deployed in Guinea, when the West Africa Ebola epidemic was detected, in March 2014, and has been used in 7 African countries and 2 US states. Epi Info VHF enabled reporting of compatible data from multiple countries, contributing to international Ebola knowledge. However, challenges were encountered in accommodating the epidemic's unexpectedly large magnitude, addressing country-specific needs within 1 software product, and using the application in settings with limited Internet access and information technology support. Use of Epi Info VHF in the West Africa Ebola epidemic highlighted the fundamental importance of good data management for effective outbreak response, regardless of the software used.

  10. Forest pricing and concession policies: Managing the high forest of west and central Africa. World Bank technical paper; Politique de redevances et de concessions forestieres: gestion des futaies en afrique occidentale et centrale

    SciTech Connect

    Grut, M.; Gray, J.A.; Egli, N.

    1993-12-01

    This French edition describes forest revenue systems and concession policies in the tropical moist hardwood forests of West and Central Africa. The paper reviews current issues in silviculture, tenure, concession management, and biological and financial sustainable development. Until the fledgling forestry departments of governments in West and Central Africa are strengthened, the report concludes that a simple system of forest fees should be implemented. The report recommends that such a system emphasize bidding and concession fees.

  11. Drug Development and Conservation of Biodiversity in West and Central Africa: Performance of Neurochemical and Radio Receptor Assays of Plant Extracts Drug Discovery for the Central Nervous System

    DTIC Science & Technology

    2004-09-01

    7) Hui, D.; Sao-Xing, C. J. Nat. Prod. 1998, 61, 142-144. (8) Aldrich Libray of 13C and 1H FT NMR spectra 1992, 2, 326A. (9) Kadota, S .; Hui, D...Biodiversity in West and Central Africa: Performance of Neurochemical and Radio Receptor Assays of Plant Extracts Drug Discovery for the Central... s ) and should not be construed as an official Department of the Army position, policy or decision unless so designated by other documentation

  12. Comparative phylogeography of African fruit bats (Chiroptera, Pteropodidae) provide new insights into the outbreak of Ebola virus disease in West Africa, 2014-2016.

    PubMed

    Hassanin, Alexandre; Nesi, Nicolas; Marin, Julie; Kadjo, Blaise; Pourrut, Xavier; Leroy, Éric; Gembu, Guy-Crispin; Musaba Akawa, Prescott; Ngoagouni, Carine; Nakouné, Emmanuel; Ruedi, Manuel; Tshikung, Didier; Pongombo Shongo, Célestin; Bonillo, Céline

    Both Ebolavirus and Marburgvirus were detected in several fruit bat species of the family Pteropodidae, suggesting that this taxon plays a key role in the life cycle of filoviruses. After four decades of Zaire Ebolavirus (ZEBOV) outbreaks in Central Africa, the virus was detected for the first time in West Africa in 2014. To better understand the role of fruit bats as potential reservoirs and circulating hosts between Central and West Africa, we examine here the phylogeny and comparative phylogeography of Pteropodidae. Our phylogenetic results confirm the existence of four independent lineages of African fruit bats: the genera Eidolon and Rousettus, and the tribes Epomophorini and Scotonycterini, and indicate that the three species suspected to represent ZEBOV reservoir hosts (Epomops franqueti, Hypsignathus monstrosus, and Myonycteris torquata) belong to an African clade that diversified rapidly around 8-7 Mya. To test for phylogeographic structure and for recent gene flow from Central to West Africa, we analysed the nucleotide variation of 675 cytochrome b gene (Cytb) sequences, representing eight fruit bat species collected in 48 geographic localities. Within Epomophorina, our mitochondrial data do not support the monophyly of two genera (Epomops and Epomophorus) and four species (Epomophorus gambianus, Epomops franqueti, Epomops buettikoferi, and Micropteropus pusillus). In Epomops, however, we found two geographic haplogroups corresponding to the Congo Basin and Upper Guinea forests, respectively. By contrast, we found no genetic differentiation between Central and West African populations for all species known to make seasonal movements, Eidolon helvum, E. gambianus, H. monstrosus, M. pusillus, Nanonycteris veldkampii, and Rousettus aegyptiacus. Our results suggest that only three fruit bat species were able to disperse directly ZEBOV from the Congo Basin to Upper Guinea: E. helvum, H. monstrosus, and R. aegyptiacus.

  13. Characterization of weathering profile in granites and volcanosedimentary rocks in West Africa under humid tropical climate conditions. Case of the Dimbokro Catchment (Ivory Coast)

    NASA Astrophysics Data System (ADS)

    Koita, M.; Jourde, H.; Koffi, K. J. P.; da Silveira, K. S.; Biaou, A.

    2013-06-01

    In granitic rocks, various models of weathering profile have been proposed, but never for the hard rocks of West Africa. Besides, in the literature there is no description of the weathering profile in volcanosedimentrary rocks. Therefore, we propose three models describing the weathering profiles in granites, metasediments, and volcanic rocks for hard rock formations located in West Africa. For each of these models proposed for granitic and volcanosedimentary rocks of the Dimbokro catchment, vertical layered weathering profiles are described, according to the various weathering and erosion cycles (specific to West Africa) that the geological formations of the Dimbokro catchment experienced from the Eocene to the recent Quaternary period. The characterization of weathering profiles is based on: i) bedrocks and weathering profile observations at outcrop, and ii) interpretation and synthesis of geophysical data and lithologs from different boreholes. For each of the geological formations (granites, metasediments, and volcanic rocks), their related weathering profile model depicted from top to bottom comprises four separate layers: alloterite, isalterite, fissured layer, and fractured fresh basement. These weathering profiles are systematically covered by a soil layer. Though granites, metasediments and volcanic rocks of the Dimbokro catchment experience the same weathering and erosion cycles during the palaeoclimatic fluctuations from Eocene to recent Quaternary period, they exhibit differences in thickness. In granites, the weathering profile is relatively thin due to the absence of iron crust which protects weathering products against dismantling. In metasediments and volcanic rocks iron crusts develop better than in granites; in these rocks the alterite are more resistant to dismantling.

  14. Influence of Neoproterozoic tectonic fabric on the origin of the Potiguar Basin, northeastern Brazil and its links with West Africa based on gravity and magnetic data

    NASA Astrophysics Data System (ADS)

    de Castro, David Lopes; Bezerra, Francisco H. R.; Sousa, Maria O. L.; Fuck, Reinhardt A.

    2012-03-01

    The Potiguar Basin is a ˜6,000 m thick aborted NE-trending rift that was formed during the Cretaceous in the continental margin of northeastern Brazil. Its ˜E-W-trending offshore faults form part of the successful continental margin rift that evolved into the South Atlantic Ocean. The region represents one of the most significant pre-Pangea breakup piercing points between eastern South America and West Africa. We used gravity, aeromagnetic, and geological data to assess the role of reactivated Precambrian shear zones and major terrain boundaries in the development of the Potiguar Basin from the Cretaceous to the Cenozoic. We also looked for possible links between these structures in northeastern Brazil and their continuation in West Africa. Our results indicate that the major fault systems of the Potiguar Basin were superimposed on the Precambrian fabric. Both gravity and magnetic maps show lineaments related to the shear zones and major terrain boundaries in the Precambrian crystalline basement, which also characterize the architecture of the rift. For example, the Carnaubais fault, the master fault of the rift system, represents the reactivation of the Portalegre shear zone, the major tectonic boundary between Precambrian terrains in the crystalline basement. In addition, part of the Moho topography is controlled by these shear zones and developed during the period of main rift extension in the Neocomian. The shear zones bounding the Potiguar rift system continue in West Africa around and underneath the Benue Basin, where fault reactivation also took place.

  15. A French-speaking speech-language pathology program in West Africa: transfer of training between Minority and Majority World countries.

    PubMed

    Topouzkhanian, Sylvia; Mijiyawa, Moustafa

    2013-02-01

    In West Africa, as in Majority World countries, people with a communication disability are generally cut-off from the normal development process. A long-term involvement of two partners (Orthophonistes du Monde and Handicap International) allowed the implementation in 2003 of the first speech-language pathology qualifying course in West Africa, within the Ecole Nationale des Auxiliaires Medicaux (ENAM, National School for Medical Auxiliaries) in Lome, Togo. It is a 3-year basic training (after the baccalaureate) in the only academic training centre for medical assistants in Togo. This department has a regional purpose and aims at training French-speaking African students. French speech-language pathology lecturers had to adapt their courses to the local realities they discovered in Togo. It was important to introduce and develop knowledge and skills in the students' system of reference. African speech-language pathologists have to face many challenges: creating an African speech and language therapy, introducing language disorders and their possible cure by means other than traditional therapies, and adapting all the evaluation tests and tools for speech-language pathology to each country, each culture, and each language. Creating an African speech-language pathology profession (according to its own standards) with a real influence in West Africa opens great opportunities for schooling and social and occupational integration of people with communication disabilities.

  16. Out of Africa

    ERIC Educational Resources Information Center

    Wilbert, Nancy Corrigan

    2009-01-01

    Karen Blixen (Isak Dinesen), author of "Out of Africa," said, "God made the world round so people would never be able to see too far down the road." The author embraced this wonderful thought by venturing on a three-week journey to Kenya and Tanzania in search of grand adventure. In this article, the author shares her adventure…

  17. Anglicising Postapartheid South Africa

    ERIC Educational Resources Information Center

    Louw, P. Eric

    2004-01-01

    The apartheid state deliberately encouraged linguistic diversity and actively built cultural infrastructures which impeded Anglicisation. With the end of apartheid has come "de facto" Anglicisation. So although South Africa has, since 1994, had 11 official languages, in reality, English is swamping the other 10 languages. Afrikaans has,…

  18. Who Speaks for Africa?

    ERIC Educational Resources Information Center

    Nealy, Michelle

    2005-01-01

    Judging by the press coverage, it would seem that Europeans are the only ones concerned about conditions in Africa, but perhaps the media is not telling the whole story. According to Mark P. Fancher, chair of the National Conference of Black Lawyers' Section on International Affairs & World Peace and the author of "The Splintering of…

  19. South Africa's Constitutional Change.

    ERIC Educational Resources Information Center

    Getman, Thomas

    1987-01-01

    Describes the striking dichotomy of South Africa's beauty and the squalor resulting from the apartheid policies of the government. Reviews reactions of black South Africans to recent constitutional changes and details efforts to secure more sweeping reform. Includes stories of several individuals who have taken actions which oppose the system of…

  20. AED in Africa

    ERIC Educational Resources Information Center

    Academy for Educational Development, 2004

    2004-01-01

    Founded in 1961, the Academy for Educational Development (AED) is an independent, nonprofit, charitable organization that operates development programs in the United States and throughout the world. This directory presents an overview of the AED programs in Africa since 1975. Current AED Programs include: (1) HIV/AIDS Prevention and Impact…

  1. AED in Africa.

    ERIC Educational Resources Information Center

    Academy for Educational Development, Washington, DC.

    For 30 years, the Academy for Educational Development (AED) has worked to support African development. In Uganda, Tanzania, and Botswana AED promoted some of Africa's first AIDS prevention programs. AED is funding research in Ethiopia, Tanzania, and perhaps Zambia that will target stigma and its role in AIDS prevention. Working with governments…

  2. Africa: Myth and Reality.

    ERIC Educational Resources Information Center

    Brown, Barbara B.

    1994-01-01

    Reports on the Third International Social Studies Conference held in Nairobi, Kenya, in 1994. Discusses democracy, educational reform efforts, and the importance of tourism to the Kenyan economy. Asserts that U.S. teachers must use accurate and nonstereotypical instructional materials in teaching about Africa. (CFR)

  3. Topical Research: Africa.

    ERIC Educational Resources Information Center

    Lynn, Karen

    This lesson plan can be used in social studies, language arts, or library research. The instructional objective is for students to select a topic of study relating to Africa, write a thesis statement, collect information from media sources, and develop a conclu