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Sample records for african nssa region

  1. Effect of biomass burning on surface ozone: A case study in 2010 over Northern Sub-Saharan Africa (NSSA)

    NASA Astrophysics Data System (ADS)

    Damoah, R.; Ichuku, C.; Ellison, L.

    2015-12-01

    One of the major sources of tropospheric ozone (O3) precursors such as nitrogen oxides (NOx), carbon monoxides (CO), and non-methane volatile organic compounds (NMVOCs) is biomass burning. The emissions from the burning do not only affect air quality and climate locally, but also on a continental to hemispheric scales through long-range transport. We have used NASA's Global Modeling Initiative Chemistry and Transport Model (GMI-CTM), to quantify the changes in surface ozone over Northern Sub-Saharan Africa (NSSA: 0 - 20N, 20W - 55E), as triggered by biomass burning from different regions. During the winter months (e.g. January), most of the burning is concentrated in the NSSA region while in summer it shifts southward outside the NSSA region. Our analysis reveals that out of the total contribution to surface ozone from biomass burning emissions in the NSSA region, 92 % is due to NSSA biomass burning while the remaining 8 % is from outside the NSSA. In fact, most (~75 %) of the 8 % comes from outside the African continent because little to no biomass burning occurs in Africa outside of the NSSA region during this time of year. However, during the summer months (e.g. July), most of the contribution to NSSA surface ozone (96 %) is due to burning from outside NSSA. Only 10 % of the 96 % comes from outside the African continent because during this time most of the burning is from outside the NSSA but within the African continent. In spring (e.g. April) approximately equal percentages of contributions come from within and outside the NSSA region.

  2. Fire and Emission Characterization in the Northern Sub-Saharan Africa (NSSA) Region and their Potential Effects on the Regional Climate System

    NASA Astrophysics Data System (ADS)

    Ellison, L.; Ichoku, C. M.

    2013-12-01

    Northern Sub-Saharan Africa (NSSA) is known for its consistent vast amounts of seasonal biomass burning each year. These mostly anthropogenic slash-and-burn fires typically used for farming and grazing purposes contributes to a significant proportion of the total global emissions of particulate matter (PM). The consequences of such severe burning could potentially have a noticeable influence on local climate patterns, such as the frequent severe droughts over the past century or the drying of Lake Chad, through both direct and indirect causes. This research therefore focuses on: 1) characterizing the burning patterns and extent within NSSA, 2) accurately quantifying PM emissions that have a direct impact on climate, and 3) exploring potential indirect impacts of burning on climate through evaluation of correlations with various environmental and meteorological parameters. In this study, the NSSA region was first split into nine distinct sub-regions to better analyze the burning patters and climatological changes. The diurnal cycle of fire radiative power (FRP, a quantifiable way of measuring fire radiant heat output) within these different regions differ in amplitude and shape, though the basic shape is the same with months of maximum FRP being between November and January and with practically no fires during the rainy season. Corresponding changes in other climatological variables were studied against changes seen in FRP on a monthly scale, including precipitation, soil moisture, surface evaporation, evapotranspiration (ET), normalized difference vegetation index (NDVI) and aerosol optical depth (AOD). This study includes an analysis of the distinct change in FRP signal that occurred in 2006 for the middle of the NSSA region, which is the area with the highest concentration of fires. A decrease in maximum monthly FRP has been observed since 2006 in this region. Regional changes in PM emissions have also been observed since then, including a large region of

  3. Interactions and Feedbacks Between Biomass Burning and Water Cycle Dynamics Across the Northern Sub-Saharan African Region

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles

    2012-01-01

    The northern sub-Saharan African (NSSA) region, bounded on the north and south by the Sahara and the Equator, respectively, and stretching from the West to the East African coastlines, has one of the highest biomass-burning rates per unit land area among all regions of the world. Because of the high concentration and frequency of fires in this region, with the associated abundance of heat release and gaseous and particulate smoke emissions, biomass-burning activity is believed to be one of the drivers of the regional carbon and energy cycles, with serious implications for the water cycle. A new interdisciplinary research effort sponsored by NASA is presently being focused on the NSSA region, to better understand the possible connection between the intense biomass burning observed from satellite year after year across the region and the rapid depletion of the regional water resources, as exemplified by the dramatic drying of Lake Chad. A combination of remote sensing and modeling approaches is being utilized in investigating multiple regional surface, atmospheric, and water-cycle processes, and inferring possible links between them. In this presentation, we will discuss preliminary results as well as the path toward improved understanding of the interrelationships and feedbacks between the biomass burning and the environmental change dynamics in the NSSA region.

  4. Assessment of the Vulnerability of Water Resources to Seasonal Fires Across the Northern Sub-Saharan African Region

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles M.

    2010-01-01

    The northern sub-Saharan African (NSSA) region, extending from the southern fringes of the Sahara to the Equator, and stretching west to east from the Atlantic to the Indian ocean coasts, plays a prominent role in the distribution of Saharan dust and other airborne matter around the region and to other parts of the world, the genesis of global atmospheric circulation, and the birth of such major (and often catastrophic) events as hurricanes. Therefore, this NSSA region represents a critical variable in the global climate change equation. Recent satellite-based studies have revealed that the NSSA region has one of the highest biomass-burning rates per unit land area among all regions of the world. Because of the high concentration and frequency of fires in this region, with the associated abundance of heat release and gaseous and particulate smoke emissions, biomass-burning activity is believed to be a major driver of the regional carbon, energy, and water cycles. We acknowledge that the rainy season in the NSSA region is from April to September while biomass burning occurs mainly during the dry season (October to March). Nevertheless, these two phenomena are indirectly coupled to each other through a chain of complex processes and conditions, including land-cover and surface-albedo changes, the carbon cycle, evapotranspiration, drought, desertification, surface water runoff, ground water recharge, and variability in atmospheric composition, heating rates, and circulation. In this presentation, we will examine the theoretical linkages between these processes, discuss the preliminary results based on satellite data analysis, and provide an overview of plans for more integrated research to be conducted over the next few years.

  5. Researching the Link Between Biomass Burning and Drought Across the Northern Sub-Saharan African Savanna/Sahel Belt

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles; Ellison, Luke

    2012-01-01

    The northern sub-Saharan African (NSSA) region, bounded by the Sahara, Equator, and the West and East African coastlines, is subjected to intense biomass burning every year during the dry season. This is believed to be one of the drivers of the regional carbon and energy cycles, with serious implications for the water cycle anomalies that probably contribute to drought and desertification. In this presentation, we will discuss a new multi-disciplinary research in the NSSA region, review progress, evaluate preliminary results, and interact with the research and user communities to examine how best to coordinate with other research activities in order to address related environmental issues most effectively.

  6. Possible Effects of Seasonal Fires on Drought Across the Northern Sub-Saharan African Region

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles

    2010-01-01

    Recent satellite-based studies have revealed that the northern sub-Saharan African (NSSA) region has one of the highest biomass-burning rates per unit land area among all regions of the world. Because of the high concentration and frequency of fires in this region, with the associated abundance of heat release and gaseous and particulate smoke emissions, biomass-burning activity is believed to be a major driver of the regional carbon, energy, and water cycles. We acknowledge that the rainy season in the NSSA region is from April to September while biomass burning occurs mainly during the dry season (October to March). Nevertheless, these two phenomena are indirectly coupled to each other through a chain of complex processes and conditions, including land-cover and surface-albedo changes, the carbon cycle, evapotranspiration, drought, desertification, surface water runoff, ground water recharge, and variability in atmospheric composition, heating rates, and circulation. In this presentation, we will examine the theoretical linkages between these processes, discuss the preliminary results based on satellite data analysis, and provide an overview of plans for more integrated research to be conducted over the next few years.

  7. Mesoscale Modeling of Smoke Particles Distribution and Their Radiative Feedback over Northern Sub-Saharan African Region

    NASA Astrophysics Data System (ADS)

    Yue, Y.; Wang, J.; Ichoku, C. M.; Ellison, L.

    2015-12-01

    Stretching from southern boundary of Sahara to the equator and expanding west to east from Atlantic Ocean coasts to the India Ocean coasts, the northern sub-Saharan African (NSSA) region has been subject to intense biomass burning. Comprised of savanna, shrub, tropical forest and a number of agricultural crops, the extensive fires burn belt covers central and south of NSSA during dry season (from October to March) contributes to one of the highest biomass burning rate per km2 in the world. Due to smoke particles' absorption effects of solar radiation, they can modify the surface and atmosphere temperature and thus change atmospheric stability, height of the boundary layer, regional atmospheric circulation, evaporation rate, cloud formation, and precipitation. Hence, smoke particles emitted from biomass burning over NSSA region has a significant influence to the air quality, weather and climate variability. In this study, the first version of this Fire Energetics and Emissions Research (FEER.v1) emissions of several smoke constituents including light-absorbing organic carbon (OC) and black carbon (BC) are applied to a state-of-science meteorology-chemistry model as NOAA Weather Research and Forecasting Model with Chemistry (WRF-Chem). We analyzed WRF-Chem simulations of surface and vertical distribution of various pollutants and their direct radiative effects in conjunction with satellite observation data from Moderate Resolution Imaging Spectroradiometer (MODIS) and Cloud-Aerosol Lidar data with Orthogonal Polarization (CALIPSO) to strengthen the importance of combining space measured emission products like FEER.v1 emission inventory with mesoscale model over intense biomass burning region, especially in area where ground-based air-quality and radiation-related observations are limited or absent.

  8. Sensitivity of Mesoscale Modeling of Smoke Direct Radiative Effect to the Emission Inventory: a Case Study in Northern Sub-Saharan African Region

    NASA Technical Reports Server (NTRS)

    Zhang, Feng; Wang, Jun; Ichoku, Charles; Hyer, Edward J.; Yang, Zhifeng; Ge, Cui; Su, Shenjian; Zhang, Xiaoyang; Kondragunta, Shobha; Kaiser, Johannes W.; Wiedinmyer, Christine; da Silva, Arlindo

    2014-01-01

    An ensemble approach is used to examine the sensitivity of smoke loading and smoke direct radiative effect in the atmosphere to uncertainties in smoke emission estimates. Seven different fire emission inventories are applied independently to WRF-Chem model (v3.5) with the same model configuration (excluding dust and other emission sources) over the northern sub-Saharan African (NSSA) biomass-burning region. Results for November and February 2010 are analyzed, respectively representing the start and end of the biomass burning season in the study region. For February 2010, estimates of total smoke emission vary by a factor of 12, but only differences by factors of 7 or less are found in the simulated regional (15degW-42degE, 13degS-17degN) and monthly averages of column PM(sub 2.5) loading, surface PM(sub 2.5) concentration, aerosol optical depth (AOD), smoke radiative forcing at the top-of-atmosphere and at the surface, and air temperature at 2 m and at 700 hPa. The smaller differences in these simulated variables may reflect the atmospheric diffusion and deposition effects to dampen the large difference in smoke emissions that are highly concentrated in areas much smaller than the regional domain of the study. Indeed, at the local scale, large differences (up to a factor of 33) persist in simulated smoke-related variables and radiative effects including semi-direct effect. Similar results are also found for November 2010, despite differences in meteorology and fire activity. Hence, biomass burning emission uncertainties have a large influence on the reliability of model simulations of atmospheric aerosol loading, transport, and radiative impacts, and this influence is largest at local and hourly-to-daily scales. Accurate quantification of smoke effects on regional climate and air quality requires further reduction of emission uncertainties, particularly for regions of high fire concentrations such as NSSA.

  9. Regional analysis of convective systems during the West African monsoon

    NASA Astrophysics Data System (ADS)

    Guy, Bradley Nicholas

    characteristics (e.g. total precipitation and vertical reflectivity profiles) at the inland and maritime sites. The wave regime also resulted in an increased population of the largest observed mesoscale convective systems observed near the coast, which led to an increase in stratiform precipitation. Despite this increase, differentiation of convective strength characteristics was less obvious between wave and no-wave regimes at the coast. Due to the propagating nature of these advecting mesoscale convective systems, interaction with the regional thermodynamic and dynamic environment appears to result in more variability than enhancements due to the wave regime, independent of location. A 13-year (1998-2010) climatology of mesoscale convective characteristics associated with the West African monsoon are also investigated using precipitation radar and passive microwave data from the NASA Tropical Rainfall Measuring Mission satellite. Seven regions defined as continental northeast and northwest, southeast and southwest, coastal, and maritime north and south are compared to analyze zonal and meridional differences. Data are categorized according to identified African easterly wave (AEW) phase and when no wave is present. While some enhancements are observed in association with AEW regimes, regional differences were generally more apparent than wave vs. no-wave differences. Convective intensity metrics confirm that land-based systems exhibit stronger characteristics, such as higher storm top and maximum 30-dBZ heights and significant 85-GHz brightness temperature depressions. Continental systems also contain a lower fraction of points identified as stratiform. Results suggest that precipitation processes also varied depending upon region and AEW regime, with warm-rain processes more apparent over the ocean and the southwest continental region and ice-based microphysics more dominant over land, including mixed-phase processes. AEW regimes did show variability in stratiform fraction and

  10. Monitoring Southern African Rainfall Season Utilizing Growing Regions

    NASA Astrophysics Data System (ADS)

    Husak, G. J.; Magadzire, T.

    2005-12-01

    Variability in timing and amount of rainfall during the growing season in southern Africa can have a dramatic impact on livelihoods in the region. This research integrates satellite model rainfall amounts with expectations for the remainder of the season to provide an envelope of likely outcomes for different growing regions. Satellite information combined with station observations combine to make the African Rainfall Climatology (ARC), which is used to estimate the start of season (SOS) and monitor the season-to-date rainfall accumulations at a pixel level. The Collaborative Historical African Rainfall Model (CHARM) - a 36-year climatology based on available station fields, global climate models and an orographic component - is used to estimate various scenarios for the remainder of the season. The season length is defined by location specific length of growing period provided by the Southern African Development Community (SADC). Once the SOS is observed according to the ARC, seasonal accumulations for each pixel begin and are evaluated at a dekadal interval. These accumulations can be compared to historical accumulations after an equal number of dekads to evaluate the progression of the season as a percentage of historical season-to-date totals for each pixel. Rainfall accumulations for the remainder of the growing period can be tallied for each year of the CHARM dataset, and Gamma probability distribution parameters can be fit to these values. Using these distribution parameters, it is possible to evaluate scenarios for the remainder of the season and combine them with the accumulations from the ARC to arrive at total rainfall accumulated during a growing period. Analysis of these totals can be compared with long-term mean accumulations for the growing period to estimate how crops will fare relative to past performance. Evaluation of various wet and dry scenarios for the remainder of the season, defined here as the 80th percentile and 20th percentile, provide an

  11. Regional environmental simulation of African cattle herding societies

    SciTech Connect

    Krummel, J.R.; Markin, J.B.; O'Neill, R.V.

    1986-03-01

    Regional analyses of the interaction between human populations and natural resources must integrate landscape scale environmental problems. An approach that considers human culture, environmental processes, and resource needs offers an appropriate methodology. With this methodology, we analyze problems of food availability in African cattle-keeping societies. The analysis interrelates cattle biomass, forage availability, milk and blood production, crop yields, gathering, food subsidies, population, and variable precipitation. While an excess of cattle leads to overgrazing, cattle also serve as valuable food storage mechanisms during low rainfall periods. Food subsidies support higher population levels but do not alter drought-induced population fluctuations. Variable precipitation patterns require solutions that stabilize year-to-year food production and also address problems of overpopulation.

  12. Extreme events evaluation over African cities with regional climate simulations

    NASA Astrophysics Data System (ADS)

    Bucchignani, Edoardo; Mercogliano, Paola; Simonis, Ingo; Engelbrecht, Francois

    2013-04-01

    The warming of the climate system in recent decades is evident from observations and is mainly related to the increase of anthropogenic greenhouse gas concentrations (IPCC, 2012). Given the expected climate change conditions on the African continent, as underlined in different publications, and their associated socio-economic impacts, an evaluation of the specific effects on some strategic African cities on the medium and long-term is of crucial importance with regard to the development of adaptation strategies. Assessments usually focus on averages climate properties rather than on variability or extremes, but often these last ones have more impacts on the society than averages values. Global Coupled Models (GCM) are generally used to simulate future climate scenarios as they guarantee physical consistency between variables; however, due to the coarse spatial resolution, their output cannot be used for impact studies on local scales, which makes necessary the generation of higher resolution climate change data. Regional Climate Models (RCM) describe better the phenomena forced by orography or by coastal lines, or that are related to convection. Therefore they can provide more detailed information on climate extremes that are hard to study and even harder to predict because they are, by definition, rare and obey different statistical laws. The normal bias of the RCM to represent the local climatology is reduced using adequate statistical techniques based on the comparison of the simulated results with long observational time series. In the framework of the EU-FP7 CLUVA (Climate Change and Urban Vulnerability in Africa) project, regional projections of climate change at high resolution (about 8 km), have been performed for selected areas surrounding five African cities. At CMCC, the regional climate model COSMO-CLM has been employed: it is a non-hydrostatic model. For each domain, two simulations have been performed, considering the RCP4.5 and RCP8.5 emission

  13. Projections of African drought extremes in CORDEX regional climate simulations

    NASA Astrophysics Data System (ADS)

    Gbobaniyi, Emiola; Nikulin, Grigory; Jones, Colin; Kjellström, Erik

    2013-04-01

    We investigate trends in drought extremes for different climate regions of the African continent over a combined historical and future period 1951-2100. Eight CMIP5 coupled atmospheric global climate models (CanESM2, CNRM-CM5, HadGEM2-ES, NorESM1-M, EC-EARTH, MIROC5, GFDL-ESM2M and MPI-ESM-LR) under two forcing scenarios, the relative concentration pathways (RCP) 4.5 and 8.5, with spatial resolution varying from about 1° to 3° are downscaled to 0.44° resolution by the Rossby Centre (SMHI) regional climate model RCA4. We use data from the ensuing ensembles of CORDEX-Africa regional climate simulations to explore three drought indices namely: standardized precipitation index (SPI), moisture index (MI) and difference in precipitation and evaporation (P-E). Meteorological and agricultural drought conditions are assessed in our analyses and a climate change signal is obtained for the SPI by calculating gamma functions for future SPI with respect to a baseline present climate. Results for the RCP4.5 and RCP8.5 scenarios are inter-compared to assess uncertainties in the future projections. We show that there is a pronounced sensitivity to the choice of forcing GCM which indicates that assessments of future drought conditions in Africa would benefit from large model ensembles. We also note that the results are sensitive to the choice of drought index. We discuss both spatial and temporal variability of drought extremes for different climate zones of Africa and the importance of the ensemble mean. Our study highlights the usefulness of CORDEX simulations in identifying possible future impacts of climate at local and regional scales.

  14. Progress toward measles preelimination--African Region, 2011-2012.

    PubMed

    Masresha, Balcha G; Kaiser, Reinhard; Eshetu, Messeret; Katsande, Reggis; Luce, Richard; Fall, Amadou; Dosseh, Annick R G A; Naouri, Boubker; Byabamazima, Charles R; Perry, Robert; Dabbagh, Alya J; Strebel, Peter; Kretsinger, Katrina; Goodson, James L; Nshimirimana, Deo

    2014-04-01

    In 2008, the 46 member states of the World Health Organization (WHO) African Region (AFR) adopted a measles preelimination goal to reach by the end of 2012 with the following targets: 1) >98% reduction in estimated regional measles mortality compared with 2000, 2) annual measles incidence of fewer than five reported cases per million population nationally, 3) >90% national first dose of measles-containing vaccine (MCV1) coverage and >80% MCV1 coverage in all districts, and 4) >95% MCV coverage in all districts by supplementary immunization activities (SIAs). Surveillance performance objectives were to report two or more cases of nonmeasles febrile rash illness per 100,000 population, one or more suspected measles cases investigated with blood specimens in ≥80% of districts, and 100% completeness of surveillance reporting from all districts. This report updates previous reports and describes progress toward the measles preelimination goal during 2011-2012. In 2012, 13 (28%) member states had >90% MCV1 coverage, and three (7%) reported >90% MCV1 coverage nationally and >80% coverage in all districts. During 2011-2012, four (15%) of 27 SIAs with available information met the target of >95% coverage in all districts. In 2012, 16 of 43 (37%) member states met the incidence target of fewer than five cases per million, and 19 of 43 (44%) met both surveillance performance targets. In 2011, the WHO Regional Committee for AFR established a goal to achieve measles elimination by 2020. To achieve this goal, intensified efforts to identify and close population immunity gaps and improve surveillance quality are needed, as well as committed leadership and ownership of the measles elimination activities and mobilization of adequate resources to complement funding from global partners. PMID:24699765

  15. Regional view of a Trans-African Drainage System

    PubMed Central

    Abdelkareem, Mohamed; El-Baz, Farouk

    2014-01-01

    Despite the arid to hyperarid climate of the Great Sahara of North Africa, pluvial climates dominated the region. Radar data shed some light on the postulated Trans-African Drainage System and its relationship to active and inactive tributaries of the Nile basin. Interpretations of recent elevation data confirm a source of the river water from the Red Sea highlands did not connect the Atlantic Ocean across Tushka basin, highlands of Uwinate and Darfur, and Chad basin, but northward to the ancestral Nile Delta. Elements of topography and climate were considered. They show that the former segments of the Nile closely mirror present-day tributaries of the Nile basin in drainage geometry, landscape, and climate. A rainfall data interpolation scenario revealed that this basin received concurrent runoff from both flanks such as Gabgaba-Allaqi to the east and Tushka basin to the west, similar to present-day Sobat and White Nile tributaries, respectively. Overall the western tributaries such as those of Tushka basin and Howar lead to the Nile, which was (and still is) the biggest river system in Africa. PMID:26257941

  16. Regional view of a Trans-African Drainage System.

    PubMed

    Abdelkareem, Mohamed; El-Baz, Farouk

    2015-05-01

    Despite the arid to hyperarid climate of the Great Sahara of North Africa, pluvial climates dominated the region. Radar data shed some light on the postulated Trans-African Drainage System and its relationship to active and inactive tributaries of the Nile basin. Interpretations of recent elevation data confirm a source of the river water from the Red Sea highlands did not connect the Atlantic Ocean across Tushka basin, highlands of Uwinate and Darfur, and Chad basin, but northward to the ancestral Nile Delta. Elements of topography and climate were considered. They show that the former segments of the Nile closely mirror present-day tributaries of the Nile basin in drainage geometry, landscape, and climate. A rainfall data interpolation scenario revealed that this basin received concurrent runoff from both flanks such as Gabgaba-Allaqi to the east and Tushka basin to the west, similar to present-day Sobat and White Nile tributaries, respectively. Overall the western tributaries such as those of Tushka basin and Howar lead to the Nile, which was (and still is) the biggest river system in Africa. PMID:26257941

  17. Lassa fever in West African sub-region: an overview.

    PubMed

    Ogbu, O; Ajuluchukwu, E; Uneke, C J

    2007-03-01

    Lassa fever is an acute viral zoonotic illness caused by Lassa virus, an arenavirus known to be responsible for a severe haemorrhagic fever characterised by fever, muscle aches, sore throat, nausea, vomiting and, chest and abdominal pain. The virus exhibits persistent, asymptomatic infection with profuse urinary virus excretion in the ubiquitous rodent vector, Mastomys natalensis. Lassa fever is endemic in West Africa and has been reported from Sierra Leone, Guinea, Liberia, and Nigeria. Some studies indicate that 300,000 to 500,000 cases of Lassa fever and 5000 deaths occur yearly across West Africa. Studies reported in English, that investigated Lassa fever with reference to West Africa were identified using the Medline Entrez-PubMed search and were used for this review. The scarcity of resources available for health care delivery system and the political instability that characterise the West African countries would continue to impede efforts for the control of Lassa fever in the sub-region. There is need for adequate training of health care workers regarding diagnostics, intensive care of patients under isolation, contact tracing, adequate precautionary measures in handling infectious laboratory specimens, control of the vector as well as care and disposal of infectious waste. PMID:17378212

  18. African-American Materials Project Experiment in Regional Cooperation. Final Report.

    ERIC Educational Resources Information Center

    Hall, Carol J.

    The African-American Materials Project was a three year venture in bibliographic control of African-American materials. It was a regional project, designed to locate and describe materials in six Southern states. The project was divided into three periods. Phase I was devoted to locating existing collections through the use of a questionnaire,…

  19. Validation of the TEC2F2 model over the African equatorial region

    NASA Astrophysics Data System (ADS)

    Ssessanga, Nicholas

    2016-06-01

    In this paper a statistical method, TEC2F2, of estimating critical F2 layer frequency (foF2) from Global Positioning System (GPS) Vertical Total Electron content (VTEC) is extended from Africa's mid-latitudes to the equatorial region, and the results validated. The equatorial region is one of the most dynamic yet under-represented over Africa in ionospheric studies. The TEC2F2 method was first considered for the South African region (mid-latitudes). This region is covered by a network of ionosondes that provided a validation platform for the TEC2F2 method before being applied to other parts of Africa. The results show that over the African equatorial region, the TEC2F2 method is a potential candidate in more accurately estimating the foF2 parameter than the most recent version of the International Reference Ionosphere (IRI-2012) model.

  20. Region of birth, migration and homicide rates of African Americans.

    PubMed

    Greenberg, M; Schneider, D

    1997-08-01

    A study was made of all homicide deaths among black Americans during the period 1979-1991 in order to test two competing hypotheses about region of birth and region of death. One hypothesis was that Southern-born blacks had the highest homicide rates in every region of the US. The competing hypothesis was that blacks who did not migrate out of their region of birth had the highest homicide rates. We found that Southern-born blacks had the highest homicide rates among the population 35+ years old in the Northeast, Midwest, South and West. Yet non-migrants (region-born population) had higher rates than their Southern-born counterparts among the population 15-34 years old. Long distance migrants who were born in the Northeast, West or were foreign-born had the lowest homicide rates, by far. The distressing implications of these findings for public health efforts to prevent violent death are discussed. PMID:9426984

  1. The Southern African Regional Science Initiative (SAFARI 2000). Dry-Season Campaign: An Overview

    NASA Technical Reports Server (NTRS)

    Swap, R. J.; Annegarn, H. J.; Suttles, J. T.; Haywood, J.; Hely, C.; Hobbs, P. V.; Holben, B. N.; Ji, J.; King, M. D.; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    The Southern African Regional Science Initiative (SAFARI 2000) is an international science project investigating the southern African earth-atmosphere-human system. The experiment was conducted over a two-year period March 1999 - March 2001. The dry season field campaign (August-Steptember 2000) was the most intensive activity and involving over 200 scientists from 18 different nations. The main objectives of this campaign were to characterize and quantify the biogenic, pyrogenic and anthropogenic aerosol and trace gas emissions and their transport and transformations in the atmosphere and to validate the NASA Earth Observing System (EOS) satellite Terra within a scientific context. Five aircraft, namely two South African Weather Service aircraft, University of Washington CV-580, the UK Meteorological Office C-130 and the NASA ER-2, with different altitude capabilities, participated in the campaign. Additional airborne sampling of southern African air masses that had moved downwind of the subcontinent was conducted by the CSIRO over Australia. Multiple observations were taken in various sectors for a variety of synoptic conditions. Flight missions were designed to maximize synchronous over-flights of the NASA TERRA satellite platform, above regional ground validation and science targets. Numerous smaller-scale ground validation activities took place throughout the region during the campaign period.

  2. Ionospheric Current System over the African Region and East Asian Region as Observed by MAGDAS Stations (Invited)

    NASA Astrophysics Data System (ADS)

    Yumoto, K.; Yamazaki, Y.; Rabiu, A.; Mahrous, A.; Meloni, A.; Baki, P.; Makundi, N.; Afullo, T.; McKinnell, L. A.; Badi, K.; Mweene, H.; Macamo, A.; Abe, S.; Ikeda, A.; Fujimoto, A.; Tokunaga, T.; Fujita, Y.; Matsuyama, K.

    2010-12-01

    The MAGnetic Data Acquisition System (MAGDAS) is the global real-time magnetometer array operated by the Space Environment Research Center (SERC), Kyushu University. This array includes two latitudinal chains; one is along the 210-degree magnetic meridian (210MM in the East Asian region since 2005). And the other is along the 96-degree magnetic meridian (96MM in the African region since 2008). The objective of this paper is to describe the longitudinal difference of the ionospheric current system using the MAGDAS data observed along the two different longitudinal chains. We analyzed the data recorded during the latest solar minimum (2008-2010) when the Sun was abnormally quiet. Our analysis shows some important characteristics of the equivalent current system over the African region: (1) From May to September, the current vortex in the Northern Hemisphere penetrates into the Southern Hemisphere in the morning hours as deeply as 40-degree at the dip latitude. (2) During this period, the strength of the equatorial electrojet becomes weaker than during other periods. These features are seen only in the current system over the African region. In the presentation, we will explain more details of the longitudinal difference of the ionospheric current system.

  3. Global diversity and genetic contributions of chicken populations from African, Asian and European regions.

    PubMed

    Lyimo, C M; Weigend, A; Msoffe, P L; Eding, H; Simianer, H; Weigend, S

    2014-12-01

    Genetic diversity and population structure of 113 chicken populations from Africa, Asia and Europe were studied using 29 microsatellite markers. Among these, three populations of wild chickens and nine commercial purebreds were used as reference populations for comparison. Compared to commercial lines and chickens sampled from the European region, high mean numbers of alleles and a high degree of heterozygosity were found in Asian and African chickens as well as in Red Junglefowl. Population differentiation (FST ) was higher among European breeds and commercial lines than among African, Asian and Red Junglefowl populations. Neighbour-Net genetic clustering and structure analysis revealed two main groups of Asian and north-west European breeds, whereas African populations overlap with other breeds from Eastern Europe and the Mediterranean region. Broilers and brown egg layers were situated between the Asian and north-west European clusters. structure analysis confirmed a lower degree of population stratification in African and Asian chickens than in European breeds. High genetic differentiation and low genetic contributions to global diversity have been observed for single European breeds. Populations with low genetic variability have also shown a low genetic contribution to a core set of diversity in attaining maximum genetic variation present from the total populations. This may indicate that conservation measures in Europe should pay special attention to preserving as many single chicken breeds as possible to maintain maximum genetic diversity given that higher genetic variations come from differentiation between breeds. PMID:25315897

  4. African Regional Seminar for Advanced Training In Systematic Curriculum Development and Evaluation. (Achimota, Ghana, 14 July--15 August 1975). Report.

    ERIC Educational Resources Information Center

    Swedish International Development Authority (SIDA).

    This report summarizes the African Regional Seminar for Advanced Training in Systematic Curriculum Development and Evaluation that was held at Achimota, Ghana, July 14-August 15 1975. Attending the seminar were 67 participants from 12 African countries, including Cameroon, Gambia, Ghana, Kenya, Liberia, Malawi, Nigeria, Sierra Leone, Swaziland,…

  5. Increase in African dust flux at the onset of commercial agriculture in the Sahel region.

    PubMed

    Mulitza, Stefan; Heslop, David; Pittauerova, Daniela; Fischer, Helmut W; Meyer, Inka; Stuut, Jan-Berend; Zabel, Matthias; Mollenhauer, Gesine; Collins, James A; Kuhnert, Henning; Schulz, Michael

    2010-07-01

    The Sahara Desert is the largest source of mineral dust in the world. Emissions of African dust increased sharply in the early 1970s (ref. 2), a change that has been attributed mainly to drought in the Sahara/Sahel region caused by changes in the global distribution of sea surface temperature. The human contribution to land degradation and dust mobilization in this region remains poorly understood, owing to the paucity of data that would allow the identification of long-term trends in desertification. Direct measurements of airborne African dust concentrations only became available in the mid-1960s from a station on Barbados and subsequently from satellite imagery since the late 1970s: they do not cover the onset of commercial agriculture in the Sahel region approximately 170 years ago. Here we construct a 3,200-year record of dust deposition off northwest Africa by investigating the chemistry and grain-size distribution of terrigenous sediments deposited at a marine site located directly under the West African dust plume. With the help of our dust record and a proxy record for West African precipitation we find that, on the century scale, dust deposition is related to precipitation in tropical West Africa until the seventeenth century. At the beginning of the nineteenth century, a sharp increase in dust deposition parallels the advent of commercial agriculture in the Sahel region. Our findings suggest that human-induced dust emissions from the Sahel region have contributed to the atmospheric dust load for about 200 years. PMID:20613839

  6. Regional Climate Modeling of West African Summer Monsoon Climate: Impact of Historical Boundary Forcing

    NASA Astrophysics Data System (ADS)

    Kebe, I.

    2015-12-01

    In this paper, we analyze and intercompare the performance of an ensemble of three Regional Climate Models (RCMs) driven by three set of Global Climate Models (GCMs), in reproducing seasonal mean climatologies with their annual cycle and the key features of West African summer monsoon over 20 years period (1985-2004) during the present day. The results show that errors in lateral boundary conditions from the GCM members, have an unexpected way on the skill of the RCMs in reproducing regional climate features such as the West African Monsoon features and the annual cycle of precipitation and temperature in terms of outperforming the GCM simulation. It also shows the occurrence of the West African Monsoon jump, the intensification and northward shift of the Saharan Heat Low (SHL) as expressed in some RCMs than the GCMs. Most RCMs also capture the mean annual cycle of precipitation and temperature, including, single and double-peaked during the summer months, in terms of events and amplitude. In a series of RCMs and GCMs experiments between the Sahara region and equatorial Africa, the presence of strong positive meridional temperature gradients at the surface and a strong meridional gradients in the potential temperatures near the surface are obvious, indicating the region of strong vertical shear development enough to establish easterly flow such as the African easterly jet. In addition, the isentropic potential vorticity (IPV) gradient decreases northward in the lower troposphere across northern Africa, with the maximum reversal on the 315-K surface. The region with negative IPV gradient favors the potential instability which has been associated with the growth of easterly waves.

  7. Impact of disaster-related mortality on gross domestic product in the WHO African Region

    PubMed Central

    Kirigia, Joses M; Sambo, Luis G; Aldis, William; Mwabu, Germano M

    2004-01-01

    Background Disaster-related mortality is a growing public health concern in the African Region. These deaths are hypothesized to have a significantly negative effect on per capita gross domestic product (GDP). The objective of this study was to estimate the loss in GDP attributable to natural and technological disaster-related mortality in the WHO African Region. Methods The impact of disaster-related mortality on GDP was estimated using double-log econometric model and cross-sectional data on various Member States in the WHO African Region. The analysis was based on 45 of the 46 countries in the Region. The data was obtained from various UNDP and World Bank publications. Results The coefficients for capital (K), educational enrolment (EN), life expectancy (LE) and exports (X) had a positive sign; while imports (M) and disaster mortality (DS) were found to impact negatively on GDP. The above-mentioned explanatory variables were found to have a statistically significant effect on GDP at 5% level in a t-distribution test. Disaster mortality of a single person was found to reduce GDP by US$0.01828. Conclusions We have demonstrated that disaster-related mortality has a significant negative effect on GDP. Thus, as policy-makers strive to increase GDP through capital investment, export promotion and increased educational enrolment, they should always keep in mind that investments made in the strengthening of national capacity to mitigate the effects of national disasters expeditiously and effectively will yield significant economic returns. PMID:15113453

  8. Impact of disaster-related mortality on gross domestic product in the WHO African Region.

    PubMed

    Kirigia, Joses M; Sambo, Luis G; Aldis, William; Mwabu, Germano M

    2004-03-15

    BACKGROUND: Disaster-related mortality is a growing public health concern in the African Region. These deaths are hypothesized to have a significantly negative effect on per capita gross domestic product (GDP). The objective of this study was to estimate the loss in GDP attributable to natural and technological disaster-related mortality in the WHO African Region. METHODS: The impact of disaster-related mortality on GDP was estimated using double-log econometric model and cross-sectional data on various Member States in the WHO African Region. The analysis was based on 45 of the 46 countries in the Region. The data was obtained from various UNDP and World Bank publications. RESULTS: The coefficients for capital (K), educational enrolment (EN), life expectancy (LE) and exports (X) had a positive sign; while imports (M) and disaster mortality (DS) were found to impact negatively on GDP. The above-mentioned explanatory variables were found to have a statistically significant effect on GDP at 5% level in a t-distribution test. Disaster mortality of a single person was found to reduce GDP by US$0.01828. CONCLUSIONS: We have demonstrated that disaster-related mortality has a significant negative effect on GDP. Thus, as policy-makers strive to increase GDP through capital investment, export promotion and increased educational enrolment, they should always keep in mind that investments made in the strengthening of national capacity to mitigate the effects of national disasters expeditiously and effectively will yield significant economic returns. PMID:15113453

  9. Effects of maternal mortality on gross domestic product (GDP) in the WHO African region.

    PubMed

    Kirigia, Joses M; Oluwole, Doyin; Mwabu, Germano M; Gatwiri, Doris; Kainyu, Lenity H

    2006-01-01

    WHO African region has got the highest maternal mortality rate compared to the other five regions. Maternal mortality is hypothesized to have significantly negative effect on the gross domestic product (GDP). The objective of the current study was to estimate the loss in GDP attributable to maternal mortality in the WHO African Region. The burden of maternal mortality on GDP was estimated using a double-log econometric model. The analysis is based on cross-sectional data for 45 of the 46 Member States in the WHO African Region. Data were obtained from UNDP and the World Bank publications. All the explanatory variables included in the double-log model were found to have statistically significant effect on per capita gross domestic product (GDP) at 5 % level in a t-distribution test. The coefficients for land (D), capital (K), educational enrollment (EN) and exports (X) had a positive sign; while labor (L), imports (M) and maternal mortality rate (MMR) were found to impact negatively on GDP. Maternal mortality of a single person was found to reduce per capita GDP by US $ 0.36 per year. The study has demonstrated that maternal mortality has a statistically significant negative effect on GDP. Thus, as policy-makers strive to increase GDP through land reform programs, capital investments, export promotion and increase in educational enrollment, they should always remember that investment in maternal mortality-reducing interventions promises significant economic returns. PMID:17348747

  10. Investigation of TEC variations over the magnetic equatorial and equatorial anomaly regions of the African sector

    NASA Astrophysics Data System (ADS)

    Oryema, B.; Jurua, E.; D'ujanga, F. M.; Ssebiyonga, N.

    2015-11-01

    This paper presents the annual, seasonal and diurnal variations in ionospheric TEC along the African equatorial region. The study also investigated the effects of a geomagnetic storm on ionospheric TEC values. Dual-frequency GPS derived TEC data obtained from four stations within the African equatorial region for the high solar activity year 2012 were used in this study. Annual variations showed TEC having two peaks in the equinoctial months, while minima values were observed in the summer and winter solstices. The diurnal pattern showed a pre-dawn minimum, a steady increase from about sunrise to an afternoon maximum and then a gradual fall after sunset to attain a minimum just before sunrise. Nighttime enhancements of TEC were observed mostly in the equinoctial months. There was comparably higher percentage TEC variability during nighttime than daytime and highest during equinoxes, moderate in winter and least during summer solstice. TEC was observed to exhibit a good correlation with geomagnetic storm indices.

  11. Southern African Phanerozoic marine invertebrates: Biogeography, pal˦oecology, climatology and comments on adjacent regions

    NASA Astrophysics Data System (ADS)

    Boucot, A. J.

    The Palaeozoic marine invertebrate fossil record in southern Africa is characterised by extensive data for the Early and Middle Devonian but extremely limited or absent for other Palaeozoic Periods. The Mesozoic Era is lacking in marine invertebrate fossils for the Triassic, Late Jurassic, and Cretaceous. For the Cenozoic Era there is limited marine megafossil information. Overall, in benthic, cool waters, Palaeozoic, marine megafossils from southern Africa appear to represent relatively low diversity communities, when compared to ecologically comparable warm water environments elsewhere. However, the marine benthic Cretaceous and Cenozoic faunas of southwestern Africa are typically diverse warm water types, until the later Miocene when cool waters again prevailed. The Benguela Current clearly influenced lower diversity faunas. Climatically, it can be inferred from the marine megabenthic pal˦ontological evidence, thatwarm conditions were present from Early Cambrian until mid-Ordovician times, followed by a much cooler climate that persisted well into the Middle Devonian. The Late Palaeozoic evidence thus indicates cool to cold conditions. In contrast, the Late Permian fossils are consistent with warmer conditions, continuing through Late Jurassic and Cretaceous times along the East African and West African coasts, until the Late Miocene. Within the Gondwanan framework, a Central African region can be envisaged that was subject to non-marine conditions during the entire Phanerozoic Eon. Peripheral to this central African region were marine environments of various ages. The geological history of these peripheral regions was fairly unique. Some features in southern Africa are similar of those found in the Paraná Basin and the Falkland Islands. Most of North Africa from central Senegal to Libya contains a Phanerozoic marine cover extending from the Early Cambrian through to the Carboniferous, characterised by warm water faunas, except for the Ordovician which yields

  12. Regional health governance: A suggested agenda for Southern African health diplomacy

    PubMed Central

    Penfold, Erica Dale; Fourie, Pieter

    2015-01-01

    Regional organisations can effectively promote regional health diplomacy and governance through engagement with regional social policy. Regional bodies make decisions about health challenges in the region, for example, the Union of South American Nations (UNASUR) and the World Health Organisation South East Asia Regional Office (WHO-SEARO). The Southern African Development Community (SADC) has a limited health presence as a regional organisation and diplomatic partner in health governance. This article identifies how SADC facilitates and coordinates health policy, arguing that SADC has the potential to promote regional health diplomacy and governance through engagement with regional social policy. The article identifies the role of global health diplomacy and niche diplomacy in health governance. The role of SADC as a regional organisation and the way it functions is then explained, focusing on how SADC engages with health issues in the region. Recommendations are made as to how SADC can play a more decisive role as a regional organisation to implement South–South management of the regional social policy, health governance and health diplomacy agenda. PMID:26635498

  13. Can countries of the WHO African Region wean themselves off donor funding for health?

    PubMed

    Kirigia, Joses Muthuri; Diarra-Nama, Alimata J

    2008-11-01

    More than 20% of total health expenditure in 48% of the 46 countries in the WHO African Region is provided by external sources. Issues surrounding aid effectiveness suggest that these countries ought to implement strategies for weaning off aid dependency. This paper broaches the following question: what are some of the strategies that countries of the region can employ to wean off donor funding for health? Five strategies are discussed: reduction in economic inefficiencies; reprioritizing public expenditures; raising additional tax revenues; increased private sector involvement in health development; and fighting corruption. PMID:19030696

  14. The Southern African Regional Science Initiative (SAFARI 2000): Overview of the Dry Season Field Campaign

    NASA Technical Reports Server (NTRS)

    Swap, R. J.; Annegarn, H. J.; Suttles, J. T.; Haywood, J.; Helmlinger, M. C.; Hely, C.; Hobbs, P. V.; Holben, B. N.; Ji, J.; King, M. D.

    2002-01-01

    The Southern African Regional Science Initiative (SAFARI 2000) is an international project investigating the earth atmosphere -human system in southern Africa. The programme was conducted over a two year period from March 1999 to March 2001. The dry season field campaign (August-September 2000) was the most intensive activity involved over 200 scientist from eighteen countries. The main objectives were to characterize and quantify biogenic, pyrogenic and anthropogenic aerosol and trace gas emissions and their transport and transformations in the atmosphere and to validate NASA's Earth Observing System's Satellite Terra within a scientific context. Five aircraft-- two South African Weather Service Aeorcommanders, the University of Washington's CV-880, the U.K. Meteorological Office's C-130, and NASA's ER-2 --with different altitude capabilities, participated in the campaign. Additional airborne sampling of southern African air masses, that had moved downwind of the subcontinent, was conducted by the CSIRO over Australia. Multiple Observations were made in various geographical sections under different synoptic conditions. Airborne missions were designed to optimize the value of synchronous over-flights of the Terra Satellite platform, above regional ground validation and science targets. Numerous smaller scale ground validation activities took place throughout the subcontinent during the campaign period.

  15. Bias reduction in decadal predictions of West African monsoon rainfall using regional climate models

    NASA Astrophysics Data System (ADS)

    Paxian, A.; Sein, D.; Panitz, H.-J.; Warscher, M.; Breil, M.; Engel, T.; Tödter, J.; Krause, A.; Cabos Narvaez, W. D.; Fink, A. H.; Ahrens, B.; Kunstmann, H.; Jacob, D.; Paeth, H.

    2016-02-01

    The West African monsoon rainfall is essential for regional food production, and decadal predictions are necessary for policy makers and farmers. However, predictions with global climate models reveal precipitation biases. This study addresses the hypotheses that global prediction biases can be reduced by dynamical downscaling with a multimodel ensemble of three regional climate models (RCMs), a RCM coupled to a global ocean model and a RCM applying more realistic soil initialization and boundary conditions, i.e., aerosols, sea surface temperatures (SSTs), vegetation, and land cover. Numerous RCM predictions have been performed with REMO, COSMO-CLM (CCLM), and Weather Research and Forecasting (WRF) in various versions and for different decades. Global predictions reveal typical positive and negative biases over the Guinea Coast and the Sahel, respectively, related to a southward shifted Intertropical Convergence Zone (ITCZ) and a positive tropical Atlantic SST bias. These rainfall biases are reduced by some regional predictions in the Sahel but aggravated by all RCMs over the Guinea Coast, resulting from the inherited SST bias, increased westerlies and evaporation over the tropical Atlantic and shifted African easterly waves. The coupled regional predictions simulate high-resolution atmosphere-ocean interactions strongly improving the SST bias, the ITCZ shift and the Guinea Coast and Central Sahel precipitation biases. Some added values in rainfall bias are found for more realistic SST and land cover boundary conditions over the Guinea Coast and improved vegetation in the Central Sahel. Thus, the ability of RCMs and improved boundary conditions to reduce rainfall biases for climate impact research depends on the considered West African region.

  16. African Anthropogenic Combustion Emissions: Estimate of Regional Mortality Attributable to Fine Particle Concentrations in 2030

    NASA Astrophysics Data System (ADS)

    Liousse, C.; Roblou, L.; Assamoi, E.; Criqui, P.; Galy-Lacaux, C.; Rosset, R.

    2014-12-01

    Fossil fuel (traffic, industries) and biofuel (domestic fires) emissions of gases and particles in Africa are expected to significantly increase in the near future, particularly due to rapid growth of African cities and megacities. In this study, we will present the most recent developments of African combustion emission inventories, including African specificities. Indeed, a regional fossil fuel and biofuel inventory for gases and particulates described in Liousse et al. (2014) has been developed for Africa at a resolution of 0.25° x 0.25° for the years 2005 and 2030. For 2005, the original database of Junker and Liousse (2008) was used after modification for updated regional fuel consumption and emission factors. Two prospective inventories for 2030 are derived based on Prospective Outlook on Long-term Energy Systems (POLES) model (Criqui, 2001). The first is a reference scenario (2030ref) with no emission controls and the second is for a "clean" scenario (2030ccc*) including Kyoto policy and African specific emission control. This inventory predicts very large increases of pollutant emissions in 2030 (e.g. contributing to 50% of global anthropogenic organic particles), if no emission regulations are implemented. These inventories have been introduced in RegCM4 model. In this paper we will focus on aerosol modelled concentrations in 2005, 2030ref and 2030ccc*. Spatial distribution of aerosol concentrations will be presented with a zoom at a few urban and rural sites. Finally mortality rates (respiratory, cardiovascular) caused by anthropogenic PM2.5 increase from 2005 to 2030, calculated following Lelieveld et al. (2013), will be shown for each scenarios. To conclude, this paper will discuss the effectiveness of scenarios to reduce emissions, aerosol concentrations and mortality rates, underlining the need for further measurements scheduled in the frame of the new DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions) program.

  17. Ethnobotanical knowledge on botanical repellents employed in the African region against mosquito vectors - A review.

    PubMed

    Pavela, Roman; Benelli, Giovanni

    2016-08-01

    Mosquitoes (Diptera: Culicidae) represent a huge threat for millions of humans and animals worldwide, since they act as vectors for important parasites and pathogens, including malaria, filariasis and important arboviruses, such as dengue, West Nile and Zika virus. No vaccines or other specific treatments are available against the arboviruses transmitted by mosquitoes, and avoidance of mosquito bites remains the best strategy. African regions are usually hit most whose inhabitants are poor, and the use of repellent plants is the only efficient protection against vectors they have. Ethnobotanical knowledge of such plants and their use is usually passed on orally from one generation to another. However, it is also important to preserve this information in a written form, as well. Ethnobotanical research projects carried out in the regions of today's Ethiopia, South Africa, Nigeria, Kenya, and Tanzania indicate that the native inhabitants of the African study regions traditionally use 64 plant species, belonging to 30 families. Aromatic plants (i.e., Citrus spp., Eucalyptus spp., Lantana camara, Ocimum spp. and Lippia javanica) the most commonly used in all the study regions. Native people know three major methods of using repellent plants: (i) production of repellent smoke from burning plants, (ii) hanging plants inside the house or sprinkling leaves on the floor, (iii) the use of plant oils, juices from crushed fresh parts of the plants, or various prepared extracts applied on uncovered body parts. Overall, this review covers studies conducted only in a limited part of the African continent, highlighting the importance to undertake further research efforts to preserve the unique knowledge and traditions of the native tribes. PMID:27260568

  18. Marine protected areas in the eastern African Region: how successful are they?

    PubMed

    Francis, Julius; Nilsson, Agneta; Waruinge, Dixon

    2002-12-01

    This article reviews the governance and management of Marine Protected Areas (MPAs), and the coral reefs they contain, in the eastern African Region. This includes the Comoros, Kenya, Madagascar, Mauritius, Mozambique, Tanzania, and the Seychelles. Three generations or categories of MPAs are distinguished: i) small areas for protection of a single species or unique marine habitat; iii) large multiple use MPAs designed for coastal development as well as biodiversity protection; and iii) MPAs managed by a nongovernmental organization (NGO) or the private sector. Each of these MPA types is examined according to the policies, legislation, and management systems they entail as well as the economic and community situation they operate within. The paper also provides a review of some eastern African MPAs in terms of their size and location, the type of MPA, zonation schemes, and financial status. The successes of the different types of MPAs are discussed based on specific indicators, such as changes in biodiversity, infrastructure, compliance to regulations and the level of involvement of primary stakeholders in the management. From the review it is clear that a fourth generation of MPAs may be forthcoming; community-based MPAs. Although lack of data makes it difficult to assess the effectiveness of these different categories of MPAs, it is clear that no MPA can succeed without support of the local communities. Generally, the results of the analysis are promising for MPAs, however a lack of data is hampering a deeper analysis. The major issues facing MPAs in the region are highlighted, as well as some regional initiatives striving to address these issues. A number of recommendations are made, aiming to strengthen the establishment and management of MPAs in the eastern African region. PMID:12572815

  19. Association studies in QTL regions linked to bovine trypanotolerance in a West African crossbred population.

    PubMed

    Dayo, G K; Gautier, M; Berthier, D; Poivey, J P; Sidibe, I; Bengaly, Z; Eggen, A; Boichard, D; Thevenon, S

    2012-04-01

    African animal trypanosomosis is a parasitic blood disease transmitted by tsetse flies and is widespread in sub-Saharan Africa. West African taurine breeds have the ability, known as trypanotolerance, to limit parasitaemia and anaemia and remain productive in enzootic areas. Several quantitative trait loci (QTL) underlying traits related to trypanotolerance have been identified in an experimentally infected F(2) population resulting from a cross between taurine and zebu cattle. Although this information is highly valuable, the QTL remain to be confirmed in populations subjected to natural conditions of infection, and the corresponding regions need to be refined. In our study, 360 West African cattle were phenotyped for the packed cell volume control under natural conditions of infection in south-western Burkina Faso. Phenotypes were assessed by analysing data from previous cattle monitored over 2 years in an area enzootic for trypanosomosis. We further genotyped for 64 microsatellite markers mapping within four previously reported QTL on BTA02, BTA04, BTA07 and BTA13. These data enabled us to estimate the heritability of the phenotype using the kinship matrix between individuals computed from genotyping data. Thus, depending on the estimators considered and the method used, the heritability of anaemia control ranged from 0.09 to 0.22. Finally, an analysis of association identified an allele of the MNB42 marker on BTA04 as being strongly associated with anaemia control, and a candidate gene, INHBA, as being close to that marker. PMID:22404348

  20. Regional distribution models with lack of proximate predictors: Africanized honeybees expanding north

    USGS Publications Warehouse

    Jarnevich, Catherine S.; Esaias, Wayne E.; Ma, Peter L.A.; Morisette, Jeffery T.; Nickeson, Jaime E.; Stohlgren, Thomas J.; Holcombe, Tracy R.; Nightingale, Joanne M.; Wolfe, Robert E.; Tan, Bin

    2014-01-01

    Species distribution models have often been hampered by poor local species data, reliance on coarse-scale climate predictors and the assumption that species–environment relationships, even with non-proximate predictors, are consistent across geographical space. Yet locally accurate maps of invasive species, such as the Africanized honeybee (AHB) in North America, are needed to support conservation efforts. Current AHB range maps are relatively coarse and are inconsistent with observed data. Our aim was to improve distribution maps using more proximate predictors (phenology) and using regional models rather than one across the entire range of interest to explore potential differences in drivers.

  1. Regional Distribution Models with Lack of Proximate Predictors: Africanized Honeybees Expanding North

    NASA Technical Reports Server (NTRS)

    Jarnevich, Catherine S.; Esaias, Wayne E.; Ma, Peter L. A.; Morisette, Jeffery T.; Nickeson, Jaime E.; Stohlgren, Thomas J.; Holcombe, Tracy R.; Nightingale, Joanne M.; Wolfe, Robert E.; Tan, Bin

    2014-01-01

    Species distribution models have often been hampered by poor local species data, reliance on coarse-scale climate predictors and the assumption that species-environment relationships, even with non-proximate predictors, are consistent across geographical space. Yet locally accurate maps of invasive species, such as the Africanized honeybee (AHB) in North America, are needed to support conservation efforts. Current AHB range maps are relatively coarse and are inconsistent with observed data. Our aim was to improve distribution maps using more proximate predictors (phenology) and using regional models rather than one across the entire range of interest to explore potential differences in drivers.

  2. Trends of ionospheric irregularities over African low latitude region during quiet geomagnetic conditions

    NASA Astrophysics Data System (ADS)

    Mungufeni, Patrick; Habarulema, John Bosco; Jurua, Edward

    2016-02-01

    The occurrence patterns of ionospheric irregularities during quiet geomagnetic conditions over the African low latitude region were analysed. GNSS-derived Total Electron Content of the ionosphere data during the period 2001-2012 were used. The data were obtained from Libreville, Gabon (0.35°N, 9.68°E, geographic, 8.05°S, magnetic), Mbarara, Uganda (0.60°S, 30.74°E, geographic, 10.22°S, magnetic), and Malindi, Kenya (2.99°S, 40.19°E, geographic, 12.42°S, magnetic). The rate of change of total electron content index greater than 0.5 TECU/Min were considered as severe ionospheric irregularities. For most of the time, the strength of ionospheric irregularities in March equinox were greater than those during September equinox over East Africa and an opposite observation was made over West Africa. These asymmetries might be due to the direction of the meridional winds during equinoxes over the different stations. Severity of ionospheric irregularity reduced from west towards the east. This might have been related to the decreasing geomagnetic field strength from east towards the west. This is the first study that reveals the equinoctial asymmetry is different in the West and East African sectors. Moreover, the importance of this study lies in the fact that it has used extensive data to examine the isolated and un-explained earlier observations of equinoctial asymmetry and longitudinal variation of ionospheric irregularities over the African low latitude region.

  3. Status of national health research systems in ten countries of the WHO African Region

    PubMed Central

    Kirigia, Joses M; Wambebe, Charles

    2006-01-01

    Background The World Health Organization (WHO) Regional Committee for Africa, in 1998, passed a resolution (AFR/RC48/R4) which urged its Member States in the Region to develop national research policies and strategies and to build national health research capacities, particularly through resource allocation, training of senior officials, strengthening of research institutions and establishment of coordination mechanisms. The purpose of this study was to take stock of some aspects of national resources for health research in the countries of the Region; identify current constraints facing national health research systems; and propose the way forward. Methods A questionnaire was prepared and sent by pouch to all the 46 Member States in the WHO African Region through the WHO Country Representatives for facilitation and follow up. The health research focal person in each of the countries Ministry of Health (in consultation with other relevant health research bodies in the country) bore the responsibility for completing the questionnaire. The data were entered and analysed in Excel spreadsheet. Results The key findings were as follows: the response rate was 21.7% (10/46); three countries had a health research policy; one country reported that it had a law relating to health research; two countries had a strategic health research plan; three countries reported that they had a functional national health research system (NHRS); two countries confirmed the existence of a functional national health research management forum (NHRMF); six countries had a functional ethical review committee (ERC); five countries had a scientific review committee (SRC); five countries reported the existence of health institutions with institutional review committees (IRC); two countries had a health research programme; and three countries had a national health research institute (NHRI) and a faculty of health sciences in the national university that conducted health research. Four out of the ten

  4. Relative rates of evolution in the coding and control regions of African mtDNAs.

    PubMed

    Howell, Neil; Elson, Joanna L; Howell, Corinna; Turnbull, Douglass M

    2007-10-01

    Reduced median networks of African haplogroup L mitochondrial DNA (mtDNA) sequences were analyzed to determine the pattern of substitutions in both the noncoding control and coding regions. In particular, we attempted to determine the causes of the previously reported (Howell et al. 2004) violation of the molecular clock during the evolution of these sequences. In the coding region, there was a significantly higher rate of substitution at synonymous sites than at nonsynonymous sites as well as in the tRNA and rRNA genes. This is further evidence for the operation of purifying selection during human mtDNA evolution. For most sites in the control region, the relative rate of substitution was similar to the rate of neutral evolution (assumed to be most closely approximated by the substitution rate at 4-fold degenerate sites). However, there are a number of mutational hot spots in the control region, approximately 3% of the total sites, that have a rate of substitution greater than the neutral rate, at some sites by more than an order of magnitude. It is possible either that these sites are evolving under conditions of positive selection or that the substitution rate at some sites in the control region is strongly dependent upon sequence context. Finally, we obtained preliminary evidence for "nonideal" evolution in the control region, including haplogroup-specific substitution patterns and a decoupling between relative rates of substitution in the control and coding regions. PMID:17642471

  5. [People of African descent in the region of the Americas and health equity].

    PubMed

    Torres, Cristina

    2002-01-01

    The Region of the Americas and the Caribbean has a complex demographic profile from an ethnic and racial perspective. One of the largest groups is composed of persons of African descent, who in some countries, such as Brazil and the Dominican Republic, comprise 46 and 84% of the total population, respectively. Recent analyses of the statistics available in some countries of the Region show wide gaps in terms of living conditions and health in these communities, as well as gaps in access to health services. PAHO, through its Public Policy and Health Program, under the Division of Health and Human Development, supports sectorial efforts and those of civil organizations that aim to improve health conditions in this segment of the population, while taking into account their sociodemographic and cultural characteristics. This article briefly summarizes health conditions and access to health services in selected countries, as well as some aspects of the recent changes to the legislation in those countries. Finally, collaborative activities on the part of United Nations agencies and international financial institutions for the benefit of people of African descent and other ethnic minorities are described. PMID:12162849

  6. Assigning African elephant DNA to geographic region of origin: Applications to the ivory trade

    PubMed Central

    Wasser, Samuel K.; Shedlock, Andrew M.; Comstock, Kenine; Ostrander, Elaine A.; Mutayoba, Benezeth; Stephens, Matthew

    2004-01-01

    Resurgence of illicit trade in African elephant ivory is placing the elephant at renewed risk. Regulation of this trade could be vastly improved by the ability to verify the geographic origin of tusks. We address this need by developing a combined genetic and statistical method to determine the origin of poached ivory. Our statistical approach exploits a smoothing method to estimate geographic-specific allele frequencies over the entire African elephants' range for 16 microsatellite loci, using 315 tissue and 84 scat samples from forest (Loxodonta africana cyclotis) and savannah (Loxodonta africana africana) elephants at 28 locations. These geographic-specific allele frequency estimates are used to infer the geographic origin of DNA samples, such as could be obtained from tusks of unknown origin. We demonstrate that our method alleviates several problems associated with standard assignment methods in this context, and the absolute accuracy of our method is high. Continent-wide, 50% of samples were located within 500 km, and 80% within 932 km of their actual place of origin. Accuracy varied by region (median accuracies: West Africa, 135 km; Central Savannah, 286 km; Central Forest, 411 km; South, 535 km; and East, 697 km). In some cases, allele frequencies vary considerably over small geographic regions, making much finer discriminations possible and suggesting that resolution could be further improved by collection of samples from locations not represented in our study. PMID:15459317

  7. Solar Spectral Radiative Forcing During the Southern African Regional Science Initiative

    NASA Technical Reports Server (NTRS)

    Pilewskie, P.; Pommier, J.; Bergstrom, R.; Gore, W.; Howard, S.; Rabbette, M.; Schmid, B.; Hobbs, P. V.; Tsay, S. C.

    2003-01-01

    During the dry season component of the Southern African Regional Science Initiative (SAFARI) in late winter 2000, the net solar spectral irradiance was measured at flight levels throughout biomass burning haze layers. From these measurements, the flux divergence, fractional absorption, instantaneous heating rate, and absorption efficiency were derived. Two cases are examined: on 24 August 2000 off the coast of Mozambique in the vicinity of Inhaca Island and on 6 September 2000 in a very thick continental haze layer over Mongu, Zambia. The measured absolute absorption was substantially higher for the case over Mongu where the measured midvisible optical depth exceeded unity. Instantaneous heating from aerosol absorption was 4 K d(sup -1) over Mongu, Zambia and 1.5 K d(sup -1) near Inhaca Island, Mozambique. However, the spectral absorption efficiency was nearly identical for both cases. Although the observations over Inhaca Island preceded the river of smoke from the southern African continent by nearly 2 weeks, the evidence here suggests a continental influence in the lower tropospheric aerosol far from source regions of burning.

  8. Analysis of Genomic Regions Associated With Coronary Artery Disease Reveals Continent-Specific Single Nucleotide Polymorphisms in North African Populations

    PubMed Central

    Zanetti, Daniela; Via, Marc; Carreras-Torres, Robert; Esteban, Esther; Chaabani, Hassen; Anaibar, Fatima; Harich, Nourdin; Habbal, Rachida; Ghalim, Noreddine; Moral, Pedro

    2016-01-01

    Background In recent years, several genomic regions have been robustly associated with coronary artery disease (CAD) in different genome-wide association studies (GWASs) conducted mainly in people of European descent. These kinds of data are lacking in African populations, even though heart diseases are a major cause of premature death and disability. Methods Here, 384 single nucleotide polymorphisms (SNPs) in the top four CAD risk regions (1p13, 1q41, 9p21, and 10q11) were genotyped in 274 case-control samples from Morocco and Tunisia, with the aim of analyzing for the first time if the associations found in European populations were transferable to North Africans. Results The results indicate that, as in Europe, these four genetic regions are also important for CAD risk in North Africa. However, the individual SNPs associated with CAD in Africa are different from those identified in Europe in most cases (1p13, 1q41, and 9p21). Moreover, the seven risk variants identified in North Africans are efficient in discriminating between cases and controls in North African populations, but not in European populations. Conclusions This study indicates a disparity in markers associated to CAD susceptibility between North Africans and Europeans that may be related to population differences in the chromosomal architecture of these risk regions. PMID:26780859

  9. The West African Monsoon simulated by global and regional climate models

    NASA Astrophysics Data System (ADS)

    Nikulin, Grigory; Jones, Colin; Kjellström, Erik; Gbobaniyi, Emiola

    2013-04-01

    We present results from two ensembles of global and regional climate simulations with a focus on the West African Monsoon (WAM). The first ensemble includes eight coupled atmosphere ocean general circulation models (AOGCMs) from the CMIP5 project, namely: CanESM2, CNRM-CM5, HadGEM2-ES, NorESM1-M, EC-EARTH, MIROC5, GFDL-ESM2M and MPI-ESM-LR. The second ensemble consists of corresponding downscaling of all 8 AOGCMs by a regional climate model - RCA4 produced at the Rossby Centre (SMHI) in the Africa-CORDEX activities. Spatial resolution varies from about 1° to 3° in the AOGCM ensemble while all regional simulations are at the same 0.44° resolution. To see what added value higher resolution can provide ability of the eight AOGCMs and the downscaled RCA4(AOGCMs) to simulate the key characteristics of the WAM rainy season are evaluated and then inter-compared between the global and regional ensembles. The main focus in our analysis is on the WAM rainy season onset, cessation, length, total precipitation, its mean intensity and intraseasonal variability. Future climate projections under the RCP45 and RCP85 scenarios are analyzed and again inter-compared for both ensembles in order to assess uncertainties in the future projections of the WAM rainy season from the global and regional ensembles.

  10. Multiple Origins and Regional Dispersal of Resistant dhps in African Plasmodium falciparum Malaria

    PubMed Central

    Pearce, Richard J.; Pota, Hirva; Evehe, Marie-Solange B.; Bâ, El-Hadj; Mombo-Ngoma, Ghyslain; Malisa, Allen L.; Ord, Rosalynn; Inojosa, Walter; Matondo, Alexandre; Diallo, Diadier A.; Mbacham, Wilfred; van den Broek, Ingrid V.; Swarthout, Todd D.; Getachew, Asefaw; Dejene, Seyoum; Grobusch, Martin P.; Njie, Fanta; Kweku, Margaret; Owusu-Agyei, Seth; Chandramohan, Daniel; Bonnet, Maryline; Guthmann, Jean-Paul; Clarke, Sian; Barnes, Karen I.; Streat, Elizabeth; Katokele, Stark T.; Uusiku, Petrina; Agboghoroma, Chris O.; Elegba, Olufunmilayo Y.; Cissé, Badara; A-Elbasit, Ishraga E.; Giha, Hayder A.; Kachur, S. Patrick; Lynch, Caroline; Rwakimari, John B.; Chanda, Pascalina; Hawela, Moonga; Naidoo, Inbarani; Roper, Cally

    2009-01-01

    Background Although the molecular basis of resistance to a number of common antimalarial drugs is well known, a geographic description of the emergence and dispersal of resistance mutations across Africa has not been attempted. To that end we have characterised the evolutionary origins of antifolate resistance mutations in the dihydropteroate synthase (dhps) gene and mapped their contemporary distribution. Methods and Findings We used microsatellite polymorphism flanking the dhps gene to determine which resistance alleles shared common ancestry and found five major lineages each of which had a unique geographical distribution. The extent to which allelic lineages were shared among 20 African Plasmodium falciparum populations revealed five major geographical groupings. Resistance lineages were common to all sites within these regions. The most marked differentiation was between east and west African P. falciparum, in which resistance alleles were not only of different ancestry but also carried different resistance mutations. Conclusions Resistant dhps has emerged independently in multiple sites in Africa during the past 10–20 years. Our data show the molecular basis of resistance differs between east and west Africa, which is likely to translate into differing antifolate sensitivity. We have also demonstrated that the dispersal patterns of resistance lineages give unique insights into recent parasite migration patterns. PMID:19365539

  11. North African petroleum geology: regional structure and stratigraphic overview of a hydrocarbon-rich cratonic area

    SciTech Connect

    O'Connor, T.E.; Kanes, W.H.

    1985-02-01

    North Africa, including Sinai, contains some of the most important hydrocarbon-producing basins in the world. The North African Symposium is devoted to examining the exploration potential of the North African margin in light of the most recent and promising exploration discoveries. The geologic variety of the region is extraordinary and can challenge any exploration philosophy. Of primary interest are the Sirte basin of Libya, which has produced several billion barrels of oil, and the Gulf of Suez, a narrow, evaporite-capped trough with five fields that will produce more than 5 billion bbl. Both are extensional basins with minimal lateral movement and with good source rocks in direct proximity to reservoirs. Structural models of these basins give firm leads for future exploration. More difficult to evaluate are the Tethyan realm basins of the northern Sinai, and the Western Desert of Egypt, the Cyrenaican Platform of Libya, and the Tunisia-Sicily shelf area, where there are only limited subsurface data. These basins are extensional in origin also, but have been influenced by lateral tectonics. Favorable reservoirs exist, but source rocks have been a problem locally. Structural models with strong stratigraphic response offer several favorable play concepts. The Paleozoic Ghadames basin in Libya, Tunisia, and Algeria has the least complex structural history, and production appears to be limited to small structures. A series of stratigraphic models indicates additional areas with exploration potential. The Paleozoic megabasin of Morocco, with its downfaulted Triassic grabens, remains an untested but attractive area.

  12. Simultaneous observations of ionospheric irregularities in the African low-latitude region

    NASA Astrophysics Data System (ADS)

    Ngwira, Chigomezyo M.; Seemala, Gopi K.; Bosco Habarulema, John

    2013-05-01

    Ionospheric storms represent large global disturbances of the ionospheric F-region electron density in response to geomagnetic storms. This study investigates the ionospheric response during a minor geomagnetic storm that occurred on 13-15 September 2004. In particular, we use total electron content (TEC) measurements (rate of TEC change, ROT) to examine the presence of ionospheric irregularities over four low-latitude stations in the African sector, a region that has been less studied. Ionospheric irregularities are known to cause fading and phase fluctuation of L-band radio navigation signals such as those used by the Global Navigation Satellite Systems (GNSS), and are a common feature in the equatorial and low-latitude ionosphere. In the present study, the storm began with a sudden commencement at approximately 20:00 UT on 13 September, while the peak of the main phase occurred on 14 September with an SYM-H index value around -59 nT. On 13 September, the storm did not appear to hinder the development of irregularities as they were observed over all the stations. In contrast, irregularities were rarely observed at two of the 4 stations under study and were absent over the other two stations on 14 September. The DSMP F15 satellite post-sunset flight over the African region observed deep density depletions on 13 September that can be associated with the presence of ionospheric plasma bubble irregularities. Furthermore, an analysis of ΔH (horizontal geomagnetic component corrected for ring current effects) shows that there was a strong positive ΔH perturbation observed in the post-sunset hours on 13 September, which suggests the presence of an eastward penetration electric field, while a negative perturbation of ΔH, which is associated with the equatorial counter-electrojet, was observed on 14 September.

  13. Africanized honey bees (Apis mellifera) have low infestation levels of the mite Varroa destructor in different ecological regions in Mexico.

    PubMed

    Medina-Flores, C A; Guzmán-Novoa, E; Hamiduzzaman, M M; Aréchiga-Flores, C F; López-Carlos, M A

    2014-01-01

    Honey bee (Apis mellifera) colonies of African and European descent were compared for levels of Varroa destructor infestation in 3 different ecological regions in Mexico. The 300 colonies that were studied were located in subtropical, temperate sub-humid, and temperate dry climates. The morphotype and mitotype of adult bees as well as their rates of infestation by varroa mites were determined. Additionally, the number of combs with brood and covered with bees was recorded for each colony. The highest frequency of colonies that were classified as African-derived was found in the subtropical environment, whereas the lowest occurred in the temperate dry region. Overall, the colonies of African genotype had significantly lower mite infestation rates (3.5±0.34%) than the colonies of European genotype (4.7±0.49%) regardless of the region sampled. Significant effects of genotype and region on Varroa infestation rates were evident, and there were no differences in bee population or capped brood between genotypes. Mite infestation levels were significantly lower in the colonies of the temperate dry region than in the colonies of the other 2 regions. These results are discussed within the context of results from studies that were previously conducted in Brazil. This is the first study that demonstrates the effects of Africanization and ecological environment on V. destructor infestation rates in honey bee colonies in North America. PMID:24634296

  14. Bacterial diversity in different regions of gastrointestinal tract of Giant African Snail (Achatina fulica)

    PubMed Central

    Pawar, Kiran D; Banskar, Sunil; Rane, Shailendra D; Charan, Shakti S; Kulkarni, Girish J; Sawant, Shailesh S; Ghate, Hemant V; Patole, Milind S; Shouche, Yogesh S

    2012-01-01

    The gastrointestinal (GI) tract of invasive land snail Achatina fulica is known to harbor metabolically active bacterial communities. In this study, we assessed the bacterial diversity in the different regions of GI tract of Giant African snail, A. fulica by culture-independent and culture-dependent methods. Five 16S rRNA gene libraries from different regions of GI tract of active snails indicated that sequences affiliated to phylum γ-Proteobacteria dominated the esophagus, crop, intestine, and rectum libraries, whereas sequences affiliated to Tenericutes dominated the stomach library. On phylogenetic analysis, 30, 27, 9, 27, and 25 operational taxonomic units (OTUs) from esophagus, crop, stomach, intestine, and rectum libraries were identified, respectively. Estimations of the total bacterial diversity covered along with environmental cluster analysis showed highest bacterial diversity in the esophagus and lowest in the stomach. Thirty-three distinct bacterial isolates were obtained, which belonged to 12 genera of two major bacterial phyla namely γ-Proteobacteria and Firmicutes. Among these, Lactococcus lactis and Kurthia gibsonii were the dominant bacteria present in all GI tract regions. Quantitative real-time polymerase chain reaction (qPCR) analysis indicated significant differences in bacterial load in different GI tract regions of active and estivating snails. The difference in the bacterial load between the intestines of active and estivating snail was maximum. Principal component analysis (PCA) of terminal restriction fragment length polymorphism suggested that bacterial community structure changes only in intestine when snail enters estivation state. PMID:23233413

  15. Responses of equatorial F region to different geomagnetic storms observed by GPS in the African sector

    NASA Astrophysics Data System (ADS)

    Adewale, A. O.; Oyeyemi, E. O.; Adeloye, A. B.; Ngwira, C. M.; Athieno, R.

    2011-12-01

    This article presents the first results regarding the investigation of the response of the equatorial ionospheric F region in the African sector during geomagnetic storm periods between April 2000 and November 2007 using GPS-derived vertical total electron content observed at Libreville, Gabon (0.35°N, 9.67°E, dip latitude -8.05°S). We performed a superposed epoch analysis of the storms by defining the start time of the epoch as the storm onset time. During geomagnetic storms, the altered electric fields contribute significantly to the occurrence of negative and positive ionospheric storm effects. Our results showed that the positive storm effects are more prevalent than the negative storm effects and generally last longer irrespective of storm onset times. Also, the positive storm effects are most pronounced in the daytime than in the premidnight and postmidnight periods.

  16. New vaccine introduction in the East and Southern African sub-region of the WHO African region in the context of GIVS and MDGs.

    PubMed

    Chauke-Moagi, Bafedile E; Mumba, Mutale

    2012-09-01

    number of countries have adopted and operationalized GIVS through comprehensive multi-year plans for immunization (cMYP). This paper reviews progress with respect to introduction of some of the new vaccines in the East and Southern sub-region of WHO African region in the context of GIVS and MDGs as well as the challenges thereof. PMID:22939018

  17. Characterisation of plumes from the Johannesburg-Pretoria megacity within the regional South African context

    NASA Astrophysics Data System (ADS)

    Beukes, J. P.; Vakkari, V.; Van Zyl, P. G.; Venter, A. D.; Josipovic, M.; Tiitta, P.; Jaars, K.; Pienaar, J. J.; Kulmala, M.; Worsnop, D.; Laakso, L.

    2012-04-01

    plumes from the more well-known source regions i.e. the Mpumalanga Highveld and the Vaal Triangle, which have been proclaimed as a national air pollution hotspots in terms of the South African National Environmental Management: Air Quality Act (Government Gazette Republic of South Africa, 2005; Government Gazette Republic of South Africa, 2007). The above-mentioned results obtained for the Johannesburg-Pretoria conurbation indicate serious air quality and climate change related impacts for the human population and regional ecosystems.

  18. Assessing the Change in Rainfall Characteristics and Trends for the Southern African ITCZ Region

    NASA Astrophysics Data System (ADS)

    Baumberg, Verena; Weber, Torsten; Helmschrot, Jörg

    2015-04-01

    Southern Africa is strongly influenced by the movement and intensity of the Intertropical Convergence Zone (ITCZ) thus determining the climate in this region with distinct seasonal and inter-annual rainfall dynamics. The amount and variability of rainfall affect the various ecosystems by controlling the hydrological system, regulating water availability and determining agricultural practices. Changes in rainfall characteristics potentially caused by climate change are of uppermost relevance for both ecosystem functioning and human well-being in this region and, thus, need to be investigated. To analyse the rainfall variability governed by the ITCZ in southern Africa, observational daily rainfall datasets with a high spatial resolution of 0.25° x 0.25° (about 28 km x 28 km) from satellite-based Tropical Rainfall Measuring Mission (TRMM) and Global Land Data Assimilation System (GLDAS) are used. These datasets extend from 1998 to 2008 and 1948 to 2010, respectively, and allow for the assessment of rainfall characteristics over different spatial and temporal scales. Furthermore, a comparison of TRMM and GLDAS and, where available, with observed data will be made to determine the differences of both datasets. In order to quantify the intra- and inner-annual variability of rainfall, the amount of total rainfall, duration of rainy seasons and number of dry spells along with further indices are calculated from the observational datasets. Over the southern African ITCZ region, the rainfall characteristics change moving from wetter north to the drier south, but also from west to east, i.e. the coast to the interior. To address expected spatial and temporal variabilities, the assessment of changes in the rainfall parameters will be carried out for different transects in zonal and meridional directions over the region affected by the ITCZ. Revealing trends over more than 60 years, the results will help to identify and understand potential impacts of climate change on

  19. Polio eradication in the World Health Organization African Region, 2008-2012.

    PubMed

    Kretsinger, Katrina; Gasasira, Alex; Poy, Alain; Porter, Kimberly A; Everts, Johannes; Salla, Mbaye; Brown, Kristin H; Wassilak, Steven G F; Nshimirimana, Deogratias

    2014-11-01

    A renewed commitment at the regional and the global levels led to substantial progress in the fight for polio eradication in the African Region (AFR) of the World Health Organization (WHO) during 2008-2012. In 2008, there were 912 reported cases of wild poliovirus (WPV) infection in 12 countries in the region. This number had been reduced to 128 cases in 3 countries in 2012, of which 122 were in Nigeria, the only remaining country with endemic circulation of WPV in AFR. During 2008-2012, circulation apparently ceased in the 3 AFR countries with reestablished WPV transmission-Angola, the Democratic Republic of the Congo, and Chad. Outbreaks in West Africa continued to occur in 2008-2010 but were more rapidly contained, with fewer cases than during earlier years. This progress has been attributed to better implementation of core strategies, increased accountability, and implementation of innovative approaches. During this period, routine coverage with 3 doses of oral polio vaccine in AFR, as measured by WHO-United Nations Children's Fund estimates, increased slightly, from 72% to 74%. Despite this progress, challenges persist in AFR, and 2013 was marked by new setbacks and importations. High population immunity and strong surveillance are essential to sustain progress and assure that AFR reaches its goal of eradicating WPV. PMID:25316840

  20. Physical impacts of regional climate change in the West African Sahel and the question of desertification

    SciTech Connect

    Nicholson, S.E.; Ba, M.

    1997-11-01

    The question of desertification is examined in the West African Sahel region by considering various physical indicators assumed to accompany this process. The study considers only the past 14 years, since the availability of comprehensive satellite data sets. The physical indicators examined include vegetation cover, surface albedo, soil moisture, wind-borne dust, river flow, lakes, and the ratio of available moisture to vegetation growth. Vegetation cover and albedo are assessed from satellite data. Soil moisture is assessed using a surface hydrologic model. Dust is estimated from visibility measurements. The most important results are that: (1) there is no progressive change in the vegetation cover, (2) an increase of albedo as the region dries up cannot be documented, and (3) there has been a tremendous increase in wind-borne dust over the Sahel. The vegetation cover responds almost directly to rainfall and the movement of the desert boundary corresponds roughly to rainfall fluctuations. The most important meteorological effect of the drought and/or desertification in the Sahel may be the enhanced dust generation, with the region becoming a major global source of atmospheric mineral dust. 5 refs., 7 figs., 1 tab.

  1. Integrated mapping of groundwater drought risk in the Southern African Development Community (SADC) region

    NASA Astrophysics Data System (ADS)

    Villholth, Karen G.; Tøttrup, Christian; Stendel, Martin; Maherry, Ashton

    2013-06-01

    Groundwater drought denotes the condition and hazard during a prolonged meteorological drought when groundwater resources decline and become unavailable or inaccessible for human use. Groundwater drought risk refers to the combined physical risk and human vulnerability associated with diminished groundwater availability and access during drought. An integrated management support tool, GRiMMS, is presented, for the mapping and assessment of relative groundwater drought risk in the Southern African Development Community (SADC) region. Based on composite mapping analysis of region-wide gridded relative indices of meteorological drought risk, hydrogeological drought proneness and human groundwater drought vulnerability, the mapping results highlight consistent areas across the region with highest groundwater drought risk and populations in the order of 39 million at risk of groundwater drought at present. Projective climate-model results suggest a potentially significant negative impact of climate change on groundwater drought risk. The tool provides a means for further attention to the key, but neglected, role of groundwater in drought management in Africa.

  2. Feedback of observed interannual vegetation change: a regional climate model analysis for the West African monsoon

    NASA Astrophysics Data System (ADS)

    Klein, Cornelia; Bliefernicht, Jan; Heinzeller, Dominikus; Gessner, Ursula; Klein, Igor; Kunstmann, Harald

    2016-06-01

    West Africa is a hot spot region for land-atmosphere coupling where atmospheric conditions and convective rainfall can strongly depend on surface characteristics. To investigate the effect of natural interannual vegetation changes on the West African monsoon precipitation, we implement satellite-derived dynamical datasets for vegetation fraction (VF), albedo and leaf area index into the Weather Research and Forecasting model. Two sets of 4-member ensembles with dynamic and static land surface description are used to extract vegetation-related changes in the interannual difference between August-September 2009 and 2010. The observed vegetation patterns retain a significant long-term memory of preceding rainfall patterns of at least 2 months. The interannual vegetation changes exhibit the strongest effect on latent heat fluxes and associated surface temperatures. We find a decrease (increase) of rainy hours over regions with higher (lower) VF during the day and the opposite during the night. The probability that maximum precipitation is shifted to nighttime (daytime) over higher (lower) VF is 12 % higher than by chance. We attribute this behaviour to horizontal circulations driven by differential heating. Over more vegetated regions, the divergence of moist air together with lower sensible heat fluxes hinders the initiation of deep convection during the day. During the night, mature convective systems cause an increase in the number of rainy hours over these regions. We identify this feedback in both water- and energy-limited regions of West Africa. The inclusion of observed dynamical surface information improved the spatial distribution of modelled rainfall in the Sahel with respect to observations, illustrating the potential of satellite data as a boundary constraint for atmospheric models.

  3. Translating the potential of hydrological forecasts into improved decision making in African regions

    NASA Astrophysics Data System (ADS)

    Sheffield, J.; He, X.; Wanders, N.; Wood, E. F.; Ali, A.; Olang, L.; Estes, L. D.; Caylor, K. K.; Evans, T. P.

    2015-12-01

    Hydrological forecasts at local scale and seasonal time scales have the potential to inform decision-making by individuals and institutions to improve management of water resources and enhance food security. Much progress has been made in recent years in understanding climate variability and its predictability over African regions. However, there remain many challenges in translating large-scale evaluations and forecasts into locally relevant information. This is hampered by lack of on the ground data of hydrological and agricultural states, and the generally low skill of climate forecasts at time scales beyond one or two weeks. Additionally, the uptake of forecasts is not prevalent because of lack of capacity, and institutional and cultural barriers to using new and uncertain information. New technologies for monitoring and forecasting relevant hydrological variables, and novel approaches to understanding how this information may be used within decision making processes, have the potential to make substantial progress in addressing these challenges. We present a quasi-operational drought and flood monitoring and forecasting system and its use in understanding the potential of hydrological forecasts for improved decision-making. The system monitors in near real-time the terrestrial water cycle for the African continent based on remote sensing data and land surface hydrological modeling. The monitoring forms initial conditions for hydrological forecasts at short time scale, aimed at flood forecasting, and seasonal scale aimed at drought and crop yield forecasts. The flood forecasts are driven by precipitation and temperature forecasts from the Global Forecast System (GFS). The drought forecasts are driven by climate forecasts from the North American Multi-Model Ensemble (NMME). The seasonal forecast skill is modest and seasonally/regionally dependent with part of the skill coming from persistence in initial land surface conditions. We discuss the use of the system

  4. Estimation of foF2 from GPS TEC over the South African region

    NASA Astrophysics Data System (ADS)

    Ssessanga, Nicholas; Mckinnell, Lee-Anne; Bosco Habarulema, John

    2014-05-01

    This paper describes a statistical method (TEC2F2) of estimating the critical frequency (foF2) values from Global Positioning System (GPS) Vertical Total Electron Content (VTEC). The method has been developed over the South African region using the available ionosonde stations; Grahamstown (33.2°S, 26.3°E), Hermanus (34.4°S, 19.2°E), Louisvale (28.5°S, 21.2°E) and Madimbo (22.4°S, 30.9°E), and nearby GPS receiver stations. The analysis of the results showed the TEC2F2 method to be more accurate at estimating the foF2 parameter over South Africa than the most commonly used International Reference Ionosphere (IRI-2012) model. On average, the TEC2F2 improves foF2 estimation by 15% (2006-2012) over the IRI-2012 model. The application of this method over the rest of Africa is proposed in order to more accurately estimate the foF2 parameter in regions where ionosondes do not exist. This is a pioneering new method that allows for the utilisation of additional resources to close the gap in ionospheric mapping over Africa.

  5. The negative impacts of human activities in the eastern African region: an international waters perspective.

    PubMed

    Payet, Rolph; Obura, David

    2004-02-01

    The complex interactions between human activities and the environment at the interface of land and water is analyzed with a focus on the Somali Current (East Africa), and Indian Ocean Island States, subregions of the Global International Waters Assessment (GIWA). These 2 subregions contain some of the world's richest ecosystems, including the high biodiversity forests of Madagascar and the diverse coastal habitats of the eastern African coast. These ecosystems support local communities and national and regional economies. Current and future degradation of these systems, from water basins to continental shelves, affects the livelihoods and sustainability of the countries in the region, and long-term efforts to reduce poverty. The assessments determined that pollution and climate change are the primary environmental and social concerns in the Islands of the Indian Ocean, while freshwater shortage and unsustainable exploitation of fisheries and other living resources are the primary environmental and social concerns in East Africa. The GIWA approach, through assessing root causes of environmental concerns, enables the development of policy approaches for mitigating environmental degradation. This paper explores policy frameworks for mitigating the impacts, and reducing the drivers, of 3 environmental concerns--freshwater shortage; solid waste pollution; and climate change--addressing social and institutional causes and effects, and linking the subregions to broad international frameworks. The common theme in all 3 case studies is the need to develop integrated ecosystem and international waters policies, and mechanisms to manage conflicting interests and to limit threats to natural processes. PMID:15083647

  6. Regional Variations in the Phonological Characteristics of African American Vernacular English.

    ERIC Educational Resources Information Center

    Hinton, Linette N.; Pollock, Karen E.

    2000-01-01

    Investigated African American Vernacular English dialect features in the midwestern community of Davenport, Iowa, and compared them to those reported by Pollock and Berni (1997) for Memphis, Tennessee--specifically productions of vocalic and postvocalic /r/ across African-American speakers from Davenport and Memphis. (Author/VWL)

  7. Political Implications of the Southern African Development Community Agenda on Educational Development in the Region.

    ERIC Educational Resources Information Center

    Nziramasanga, Caiphas T.

    This paper briefly describes the historical development of the Southern African Development Coordination Conference (SADCC) from its roots in 1980 and examines the work of the Southern African Development Community (SADC) today. The objectives of the SADCC are listed from the 1980 declaration and the achievement of those objectives are assessed.…

  8. African Regional Symposium on Telematics for Development. Report and Recommendations = Colloque regional africain la telematique au service du developpement. Rapport et recommandations (Addis Ababa, Ethiopia, April 3-7, 1995).

    ERIC Educational Resources Information Center

    International Telecommunication Union, Geneva (Switzerland).

    The African Regional Symposium on Telematics for Development was organized in view of the special educational and communication needs of Africa in a time of accelerating change and development of information technologies. The symposium brought together more than 150 African specialists, and over 40 participants from other regions and development…

  9. Optical, physical and chemical properties of transported African mineral dust aerosols in the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Denjean, Cyrielle; Di Biagio, Claudia; Chevaillier, Servanne; Gaimoz, Cécile; Grand, Noel; Loisil, Rodrigue; Triquet, Sylvain; Zapf, Pascal; Roberts, Greg; Bourrianne, Thierry; Torres, Benjamin; Blarel, Luc; Sellegri, Karine; Freney, Evelyn; Schwarzenbock, Alfons; Ravetta, François; Laurent, Benoit; Mallet, Marc; Formenti, Paola

    2014-05-01

    The transport of mineral dust aerosols is a global phenomenon with strong climate implications. Depending on the travel distance over source regions, the atmospheric conditions and the residence time in the atmosphere, various transformation processes (size-selective sedimentation, mixing, condensation of gaseous species, and weathering) can modify the physical and chemical properties of mineral dust, which, in turn, can change the dust's optical properties. The model predictions of the radiative effect by mineral dust still suffer of the lack of certainty of these properties, and their temporal evolution with transport time. Within the frame of the ChArMex project (Chemistry-Aerosol Mediterranean experiment, http://charmex.lsce.ipsl.fr/), two intensive airborne campaigns (TRAQA, TRansport and Air QuAlity, 18 June - 11 July 2012, and ADRIMED, Aerosol Direct Radiative Impact in the regional climate in the MEDiterranean region, 06 June - 08 July 2013) have been performed over the Central and Western Mediterranean, one of the two major transport pathways of African mineral dust. In this study we have set up a systematic strategy to determine the optical, physical and optical properties of mineral dust to be compared to an equivalent dataset for dust close to source regions in Africa. This study is based on airborne observations onboard the SAFIRE ATR-42 aircraft, equipped with state of the art in situ instrumentation to measure the particle scattering and backscattering coefficients (nephelometer at 450, 550, and 700 nm), the absorption coefficient (PSAP at 467, 530, and 660 nm), the extinction coefficient (CAPS at 530 nm), the aerosol optical depth (PLASMA at 340 to 1640 nm), the size distribution in the extended range 40 nm - 30 µm by the combination of different particle counters (SMPS, USHAS, FSSP, GRIMM) and the chemical composition obtained by filter sampling. The chemistry and transport model CHIMERE-Dust have been used to classify the air masses according to

  10. Properties of transported African mineral dust aerosols in the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Denjean, Cyrielle; Chevaillier, Servanne; Gaimoz, Cécile; Grand, Noel; Triquet, Sylvain; Zapf, Pascal; Loisil, Rodrigue; Bourrianne, Thierry; Freney, Evelyn; Dupuy, Regis; Sellegri, Karine; Schwarzenbock, Alfons; Torres, Benjamin; Mallet, Marc; Cassola, Federico; Prati, Paolo; Formenti, Paola

    2015-04-01

    The transport of mineral dust aerosols is a global phenomenon with strong climate implications. Depending on the travel distance over source regions, the atmospheric conditions and the residence time in the atmosphere, various transformation processes (size-selective sedimentation, mixing, condensation of gaseous species, and weathering) can modify the physical and chemical properties of mineral dust, which, in turn, can change the dust's optical properties. The model predictions of the radiative effect by mineral dust still suffer of the lack of certainty of these properties, and their temporal evolution with transport time. Within the frame of the ChArMex project (Chemistry-Aerosol Mediterranean experiment, http://charmex.lsce.ipsl.fr/), one intensive airborne campaign (ADRIMED, Aerosol Direct Radiative Impact in the regional climate in the MEDiterranean region, 06 June - 08 July 2013) has been performed over the Central and Western Mediterranean, one of the two major transport pathways of African mineral dust. In this study we have set up a systematic strategy to determine the optical, physical and optical properties of mineral dust to be compared to an equivalent dataset for dust close to source regions in Africa. This study is based on airborne observations onboard the SAFIRE ATR-42 aircraft, equipped with state of the art in situ instrumentation to measure the particle scattering and backscattering coefficients (nephelometer at 450, 550, and 700 nm), the absorption coefficient (PSAP at 467, 530, and 660 nm), the extinction coefficient (CAPS at 530 nm), the aerosol optical depth (PLASMA at 340 to 1640 nm), the size distribution in the extended range 40 nm - 30 µm by the combination of different particle counters (SMPS, USHAS, FSSP, GRIMM) and the chemical composition obtained by filter sampling. The chemistry and transport model CHIMERE-Dust have been used to classify the air masses according to the dust origin and transport. Case studies of dust transport

  11. Exploring child prostitution in a major city in the West African region.

    PubMed

    Hounmenou, Charles

    2016-09-01

    The study explored the characteristics of child prostitution in a major city in the West African region. A convenience sample of children in prostitution, specifically girls below age 18 (n=243), were recruited on 83 prostitution sites identified in Ouagadougou, the capital city of Burkina Faso. A survey instrument, consisting of 71 closed-ended question items, was used to explore various variables including profile of children in prostitution, factors of vulnerability to prostitution; prostitution practices, compensations and related issues in child prostitution. The findings show that most children in prostitution in the city were from Burkina Faso (63%) and Nigeria (30%), two countries that do not share borders. Most native respondents practiced prostitution for survival and to support their families. In contrast, all the respondents from Nigeria practiced prostitution as victims of international sex trafficking. An important finding was that 77% of the children in prostitution surveyed were educated. Among the respondents, there were similarities in the major life events that contributed to their situation of prostitution. These life events include early separation with parents, sexual abuse, foster care, and forced marriage. Implications for policy, practice and research are discussed. PMID:27490517

  12. Tracking cashew economically important diseases in the West African region using metagenomics.

    PubMed

    Monteiro, Filipa; Romeiras, Maria M; Figueiredo, Andreia; Sebastiana, Mónica; Baldé, Aladje; Catarino, Luís; Batista, Dora

    2015-01-01

    During the last decades, agricultural land-uses in West Africa were marked by dramatic shifts in the coverage of individual crops. Nowadays, cashew (Anacardium occidentale L.) is one of the most export-oriented horticulture crops, notably in Guinea-Bissau. Relying heavily on agriculture to increase their income, developing countries have been following a strong trend of moving on from traditional farming systems toward commercial production. Emerging infectious diseases, driven either by adaptation to local conditions or inadvertent importation of plant pathogens, are able to cause tremendous cashew production losses, with economic and social impact of which, in developing countries is often underestimated. Presently, plant genomics with metagenomics as an emergent tool, presents an enormous potential to better characterize diseases by providing extensive knowledge on plant pathogens at a large scale. In this perspective, we address metagenomics as a promising genomic tool to identify cashew fungal associated diseases as well as to discriminate the causal pathogens, aiming at obtaining tools to help design effective strategies for disease control and thus promote the sustainable production of cashew in West African Region. PMID:26175748

  13. Tracking cashew economically important diseases in the West African region using metagenomics

    PubMed Central

    Monteiro, Filipa; Romeiras, Maria M.; Figueiredo, Andreia; Sebastiana, Mónica; Baldé, Aladje; Catarino, Luís; Batista, Dora

    2015-01-01

    During the last decades, agricultural land-uses in West Africa were marked by dramatic shifts in the coverage of individual crops. Nowadays, cashew (Anacardium occidentale L.) is one of the most export-oriented horticulture crops, notably in Guinea-Bissau. Relying heavily on agriculture to increase their income, developing countries have been following a strong trend of moving on from traditional farming systems toward commercial production. Emerging infectious diseases, driven either by adaptation to local conditions or inadvertent importation of plant pathogens, are able to cause tremendous cashew production losses, with economic and social impact of which, in developing countries is often underestimated. Presently, plant genomics with metagenomics as an emergent tool, presents an enormous potential to better characterize diseases by providing extensive knowledge on plant pathogens at a large scale. In this perspective, we address metagenomics as a promising genomic tool to identify cashew fungal associated diseases as well as to discriminate the causal pathogens, aiming at obtaining tools to help design effective strategies for disease control and thus promote the sustainable production of cashew in West African Region. PMID:26175748

  14. Identifying transboundary aquifers in need of international resource management in the Southern African Development Community region

    NASA Astrophysics Data System (ADS)

    Davies, Jeff; Robins, Nick S.; Farr, John; Sorensen, James; Beetlestone, Philip; Cobbing, Jude E.

    2013-03-01

    Transboundary aquifer (TBA) management, in part, seeks to mitigate degradation of groundwater resources caused either by an imbalance of abstraction between countries or by cross-border pollution. Fourteen potential TBAs were identified within a hydrogeological mapping programme based on simple hydrogeological selection criteria for the Southern African Development Community (SADC) region. These have been reassessed against a set of data associated with five categories: (1) groundwater flow and vulnerability (which is perceived as the over-arching influence on the activity level of each TBA), (2) knowledge and understanding, (3) governance capability, (4) socio-economic/water-demand factors, and (5) environmental issues. These assessments enable the TBAs to be classified according to their need for cross-border co-operation and management. The study shows that only two of the 14 TBAs have potential to be the cause of tension between neighbouring states, while nine are potentially troublesome and three are unlikely to become problematic even in the future. The classification highlights the need to focus on data gathering to enable improved understanding of the TBAs that could potentially become troublesome in the future due to, for example, change in demographics and climate.

  15. Africans in America.

    ERIC Educational Resources Information Center

    Hart, Ayanna; Spangler, Earl

    This book introduces African-American history and culture to children. The first Africans in America came from many different regions and cultures, but became united in this country by being black, African, and slaves. Once in America, Africans began a long struggle for freedom which still continues. Slavery, the Civil War, emancipation, and the…

  16. Capacity Building and Financing Oral Health in the African and Middle East Region.

    PubMed

    Mumghamba, E G; Joury, E; Fatusi, O; Ober-Oluoch, J; Onigbanjo, R J; Honkala, S

    2015-07-01

    Many low- and middle-income countries do not yet have policies to implement effective oral health programs. A reason is lack of human and financial resources. Gaps between resource needs and available health funding are widening. By building capacity, countries aim to improve oral health through actions by oral health care personnel and oral health care organizations and their communities. Capacity building involves achieving measurable and sustainable results in training, research, and provision of care. Actions include advancement of knowledge, attitudes and skills, expansion of support, and development of cohesiveness and partnerships. The aim of this critical review is to review existing knowledge and identify gaps and variations between and within different income levels in relation to the capacity building and financing oral health in the African and Middle East region (AMER). A second aim is to formulate research priorities and outline a research agenda for capacity building and financing to improve oral health and reduce oral health inequalities in the AMER. The article focuses on capacity building for oral health and oral health financing in the AMER of the IADR. In many communities in the AMER, there are clear and widening gaps between the dental needs and the existing capacity to meet these needs in terms of financial and human resources. Concerted efforts are required to improve access to oral health care through appropriate financing mechanisms, innovative health insurance schemes, and donor support and move toward universal oral health care coverage to reduce social inequality in the region. It is necessary to build capacity and incentivize the workforce to render evidence-based services as well as accessing funds to conduct research on equity and social determinants of oral health while promoting community engagement and a multidisciplinary approach. PMID:26101338

  17. Impact of burned areas on the northern African seasonal climate from the perspective of regional modeling

    NASA Astrophysics Data System (ADS)

    De Sales, F.; Xue, Y.; Okin, G. S.

    2014-12-01

    This study presents an investigation of the impact of burned areas on the surface energy balance and monthly precipitation in the northern Africa as simulated by a state-of-the-art regional model. Mean burned area fraction derived from MODIS approximate date of burning product were implemented in a set of 1-year long WRF/NMM/SSiB2 model simulations. Vegetation cover fraction and LAI were degraded daily based on mean burned area fraction and on the survival rate for each vegetation land cover type. Additionally, ground darkening associated with wildfire-induced ash and charcoal deposition was temporarily imposed through lower ground albedo for a period of 10 days after burning. In general, wildfire-induced vegetation and ground degradation increased surface albedo by exposing the brighter bare ground of the region, which in turn caused a decrease in surface net radiation and evapotranspiration in northern sub-saharan Africa. A decrease in atmospheric moisture flux convergence was simulated in the burned area experiments, which plays a dominant role in reducing precipitation over the area, especially in the months preceding the West African monsoon onset. The areas with largest impacts were those covered by forests and savanna, where annual precipitation decreased by 4.2% and 3.6%, respectively. This study suggests the cooling and drying of atmosphere induced by burned areas led to strengthening of subsidence during pre-onset and weakening of upward motion during onset and mature stages of the monsoon leading to a waning of convective instability and precipitation. Monthly vertical wind over the area showed a strengthening of downward motion in winter and spring seasons, and weakening of upward movement during the rainy months. Furthermore, precipitation energy analysis revealed that most of precipitation decrease originated from convective events, especially for those with daily precipitation rates above 2.0 mm day-1, which substantiates the hypothesis of convective

  18. The Chew Bahir Project, southern Ethiopia: Reconstructing East African palaeoenvironments in the source region of modern man

    NASA Astrophysics Data System (ADS)

    Foerster, V. E.; Chew Bahir Science Team

    2011-12-01

    Chew Bahir is a tectonically bounded basin in the southern part of the Main Ethiopian Rift and in close proximity to the Omo valley, which contains some of the oldest known early modern human sites. As East African palaeoenvironments are highly variable and marked by extreme fluctuations in moisture availability, this in turn bears far reaching implications for the life, evolution and most notably for the expansion of Homo sapiens beyond the limits of the African continent. This study is a prerequisite for the ICDP- Hominin Sites And Paleolakes Drilling Project and part of the CRC-806 "Our way to Europe". The Chew Bahir Project will provide fundamental data to reconstruct late Quaternary East African environments including the timing, amplitude, synchronicity and abruptness of dry-wet-dry cycles and focuses on the interaction between those rapid climate shifts and their influence on the biosphere. This poster presents results from six cores (9-18m depth) from a NW-SE transect across the Chew Bahir basin that have recorded the climatic history of the past 45 ka and therewith can potentially elucidate those highly variable East African palaeoenvironments with emphasis on the last of the wet periods, the African Humid Period (AHP). Based on a series of multi-proxy analyses, comprising geochemical, physical and biological indicators as well as AMS 14C dates, it becomes obvious that the Chew Bahir responds decidedly sensitive towards even minor climatic fluctuations on millennial to even centennial timescales. Therefore, the Chew Bahir represents a unique site to reveal the impact of timing and mechanisms of local, regional and global climate events on the key region for humankind.

  19. Novel swine virulence determinant in the left variable region of the African swine fever virus genome.

    PubMed

    Neilan, J G; Zsak, L; Lu, Z; Kutish, G F; Afonso, C L; Rock, D L

    2002-04-01

    Previously we have shown that the African swine fever virus (ASFV) NL gene deletion mutant E70DeltaNL is attenuated in pigs. Our recent observations that NL gene deletion mutants of two additional pathogenic ASFV isolates, Malawi Lil-20/1 and Pr4, remained highly virulent in swine (100% mortality) suggested that these isolates encoded an additional virulence determinant(s) that was absent from E70. To map this putative virulence determinant, in vivo marker rescue experiments were performed by inoculating swine with infection-transfection lysates containing E70 NL deletion mutant virus (E70DeltaNL) and cosmid DNA clones from the Malawi NL gene deletion mutant (MalDeltaNL). A cosmid clone representing the left-hand 38-kb region (map units 0.05 to 0.26) of the MalDeltaNL genome was capable of restoring full virulence to E70DeltaNL. Southern blot analysis of recovered virulent viruses confirmed that they were recombinant E70DeltaNL genomes containing a 23- to 28-kb DNA fragment of the Malawi genome. These recombinants exhibited an unaltered MalDeltaNL disease and virulence phenotype when inoculated into swine. Additional in vivo marker rescue experiments identified a 20-kb fragment, encoding members of multigene families (MGF) 360 and 530, as being capable of fully restoring virulence to E70DeltaNL. Comparative nucleotide sequence analysis of the left variable region of the E70DeltaNL and Malawi Lil-20/1 genomes identified an 8-kb deletion in the E70DeltaNL isolate which resulted in the deletion and/or truncation of three MGF 360 genes and four MGF 530 genes. A recombinant MalDeltaNL deletion mutant lacking three members of each MGF gene family was constructed and evaluated for virulence in swine. The mutant virus replicated normally in macrophage cell culture but was avirulent in swine. Together, these results indicate that a region within the left variable region of the ASFV genome containing the MGF 360 and 530 genes represents a previously unrecognized virulence

  20. Novel Swine Virulence Determinant in the Left Variable Region of the African Swine Fever Virus Genome

    PubMed Central

    Neilan, J. G.; Zsak, L.; Lu, Z.; Kutish, G. F.; Afonso, C. L.; Rock, D. L.

    2002-01-01

    Previously we have shown that the African swine fever virus (ASFV) NL gene deletion mutant E70ΔNL is attenuated in pigs. Our recent observations that NL gene deletion mutants of two additional pathogenic ASFV isolates, Malawi Lil-20/1 and Pr4, remained highly virulent in swine (100% mortality) suggested that these isolates encoded an additional virulence determinant(s) that was absent from E70. To map this putative virulence determinant, in vivo marker rescue experiments were performed by inoculating swine with infection-transfection lysates containing E70 NL deletion mutant virus (E70ΔNL) and cosmid DNA clones from the Malawi NL gene deletion mutant (MalΔNL). A cosmid clone representing the left-hand 38-kb region (map units 0.05 to 0.26) of the MalΔNL genome was capable of restoring full virulence to E70ΔNL. Southern blot analysis of recovered virulent viruses confirmed that they were recombinant E70ΔNL genomes containing a 23- to 28-kb DNA fragment of the Malawi genome. These recombinants exhibited an unaltered MalΔNL disease and virulence phenotype when inoculated into swine. Additional in vivo marker rescue experiments identified a 20-kb fragment, encoding members of multigene families (MGF) 360 and 530, as being capable of fully restoring virulence to E70ΔNL. Comparative nucleotide sequence analysis of the left variable region of the E70ΔNL and Malawi Lil-20/1 genomes identified an 8-kb deletion in the E70ΔNL isolate which resulted in the deletion and/or truncation of three MGF 360 genes and four MGF 530 genes. A recombinant MalΔNL deletion mutant lacking three members of each MGF gene family was constructed and evaluated for virulence in swine. The mutant virus replicated normally in macrophage cell culture but was avirulent in swine. Together, these results indicate that a region within the left variable region of the ASFV genome containing the MGF 360 and 530 genes represents a previously unrecognized virulence determinant for domestic swine

  1. MEDCAN-GRO: Medical Capacity for African Nations - Growing Regional Operability A Case Study in Special Operations Forces Capacity Building.

    PubMed

    Givens, Melissa L; Verlo, April

    2015-01-01

    Medical Capacity for African Nations-Growing Regional Operability (MEDCAN-GRO) is a framework for addressing healthcare engagements that are intended to provide sustainable capacity building with partner nations. MEDCAN-GRO provides SOF units with a model that can be scaled to partner nation needs and aligned with the goals of the TSOC in an effort to enhance partner nation security. PMID:25770807

  2. Impact of burned areas on the northern African seasonal climate from the perspective of regional modeling

    NASA Astrophysics Data System (ADS)

    De Sales, Fernando; Xue, Yongkang; Okin, Gregory S.

    2015-02-01

    This study investigates the impact of burned areas on the surface energy balance and monthly precipitation in northern Africa as simulated by a state-of-the-art regional model. Mean burned area fraction derived from MODIS date of burning product was implemented in a set of 1-year long WRF-NMM/SSiB2 model simulations. Vegetation cover fraction and LAI were degraded daily based on mean burned area fraction and on the survival rate for each vegetation land cover type. Additionally, ground darkening associated with wildfire-induced ash and charcoal deposition was imposed through lower ground albedo for a period after burning. In general, wildfire-induced vegetation and ground condition deterioration increased mean surface albedo by exposing the brighter bare ground, which in turn caused a decrease in monthly surface net radiation. On average, the wildfire-season albedo increase was approximately 6.3 % over the Sahel. The associated decrease in surface available energy caused a drop in surface sensible heat flux to the atmosphere during the dry months of winter and early spring, which gradually transitioned to a more substantial decrease in surface evapotranspiration in April and May that lessened throughout the rainy season. Overall, post-fire land condition deterioration resulted in a decrease in precipitation over sub-Saharan Africa, associated with the weakening of the West African monsoon progression through the region. A decrease in atmospheric moisture flux convergence was observed in the burned area simulations, which played a dominant role in reducing precipitation in the area, especially in the months preceding the monsoon onset. The areas with the largest precipitation impact were those covered by savannas and rainforests, where annual precipitation decreased by 3.8 and 3.3 %, respectively. The resulting precipitation decrease and vegetation deterioration caused a drop in gross primary productivity in the region, which was strongest in late winter and early

  3. Climatology and dynamics of nocturnal low-level stratus over the southern West African monsoon region

    NASA Astrophysics Data System (ADS)

    Fink, A. H.; Schuster, R.; Knippertz, P.; van der Linden, R.

    2013-12-01

    The southern parts of West Africa, from the coast to about 10°N, are frequently covered by an extensive deck of shallow, low (200 - 400 m above ground) stratus or stratocumulus clouds during the summer monsoon season. These clouds usually form at night in association with a nocturnal low-level jet (NLLJ) and can persist into the early afternoon hours until they are dissipated or replaced by fair-weather cumuli. Recent work suggests that the stratus deck and its effect on the surface radiation balance are unsatisfactorily represented in standard satellite retrievals and simulations by state-of-the-art climate models. We will present the first ever climatology of the diurnal cycle of the low cloud deck based on surface observations and satellite products. In addition, we use high-resolution regional simulations with the Weather Research and Forecast (WRF) model and observations from the African Monsoon Multidisciplinary Analysis (AMMA) 2006 campaign to investigate (a) the spatiotemporal distribution, (b) the influence on the radiation balance, and (c) the detailed formation and maintenance mechanisms of the stratiform clouds as simulated by the model. The model configuration used for this study has been determined following an extensive sensitivity study, which has shown that at least some configurations of WRF satisfactorily reproduce the diurnal cycle of the low cloud evolution. The main conclusions are: (a) The observed stratus deck forms after sunset along the coast, spreads inland in the course of the night, reaches maximum poleward extent at about 10°N around 09-10 local time and dissipates in the early afternoon. (b) The average surface net radiation balance in stratus-dominated regions is 35 W m-2 lower than in those with less clouds. (c) The cloud formation is related to a subtle balance between 'stratogenic' upward (downward) fluxes of latent (sensible) heat caused by shear-driven turbulence below the NLLJ, cold advection from the ocean, forced lifting at

  4. Oral Health Inequalities between Rural and Urban Populations of the African and Middle East Region.

    PubMed

    Ogunbodede, E O; Kida, I A; Madjapa, H S; Amedari, M; Ehizele, A; Mutave, R; Sodipo, B; Temilola, S; Okoye, L

    2015-07-01

    Although there have been major improvements in oral health, with remarkable advances in the prevention and management of oral diseases, globally, inequalities persist between urban and rural communities. These inequalities exist in the distribution of oral health services, accessibility, utilization, treatment outcomes, oral health knowledge and practices, health insurance coverage, oral health-related quality of life, and prevalence of oral diseases, among others. People living in rural areas are likely to be poorer, be less health literate, have more caries, have fewer teeth, have no health insurance coverage, and have less money to spend on dental care than persons living in urban areas. Rural areas are often associated with lower education levels, which in turn have been found to be related to lower levels of health literacy and poor use of health care services. These factors have an impact on oral health care, service delivery, and research. Hence, unmet dental care remains one of the most urgent health care needs in these communities. We highlight some of the conceptual issues relating to urban-rural inequalities in oral health, especially in the African and Middle East Region (AMER). Actions to reduce oral health inequalities and ameliorate rural-urban disparity are necessary both within the health sector and the wider policy environment. Recommended actions include population-specific oral health promotion programs, measures aimed at increasing access to oral health services in rural areas, integration of oral health into existing primary health care services, and support for research aimed at informing policy on the social determinants of health. Concerted efforts must be made by all stakeholders (governments, health care workforce, organizations, and communities) to reduce disparities and improve oral health outcomes in underserved populations. PMID:26101336

  5. Cattle ticks in Cameroon: is Rhipicephalus (Boophilus) microplus absent in Cameroon and the Central African region?

    PubMed

    Awa, D N; Adakal, H; Luogbou, N D D; Wachong, K H; Leinyuy, I; Achukwi, M D

    2015-03-01

    In most parts of the world, ticks are rapidly developing resistance to commonly used acaricides thus rendering control difficult. This constraint is further compounded by the introduction of new species in areas where they did not exist before. Such is the case with the introduction into and rapid spread of Rhipicephalus (Boophilus) microplus in some countries of West Africa. With the looming threat of its further spread in the region, the objective of the present study was to update knowledge on cattle ticks in Cameroon. Among 19,189 ticks collected monthly from 60 animals in 5 herds from March 2012 to February 2013, Rh. (B.) decoloratus was the most abundant species with a relative prevalence of 62.2%, followed by Amblyomma variegatum (28.4%), Rh. (B.) annulatus (0.2%), Rh. (B.) geigyi (0.03%), other Rhipicephalus spp. (8.4%) and Hyalomma spp. (0.3%). Rh. (B.) decoloratus and A. variegatum were also the most widely distributed in space. Infestation rate was generally high, with average tick count/animal of about 80 during peak periods. Tick distribution and abundance in the different sites was as varied as the underlying factors, among which the most important were management systems and climatic factors. The effects of rainfall and temperature were confounded by other factors and difficult to evaluate. However, it appears tick development depends among other factors, on a humidity threshold, above which there is not much more effect. Rh. microplus was not found during this study, but more extensive tick collections have to be done to confirm this. In conclusion, cattle tick infestation in Cameroon remains an important cause for concern. Farmers need assistance in the use and management of acaricides in order to increase their efficiency and reduce the development of resistance. Although Rh. microplus was not found, its introduction from other West African countries is imminent if adequate measures, especially in the control and limitation of animal movements

  6. Modelling of ionospheric irregularities during geomagnetic storms over African low latitude region

    NASA Astrophysics Data System (ADS)

    Mungufeni, Patrick

    2016-07-01

    In this study, empirical models of occurrence of ionospheric irregularities over low latitude African region during geomagnetic storms have been developed. The geomagnetic storms considered consisted of Dst ≤ -50 nT. GNSS-derived ionospheric Total Electron Content (TEC) data over Libreville, Gabon (NKLG) (0.35° N, 9.68° E, geographic, 8.05° S, magnetic) and Malindi, Kenya (MAL2) (2.99° S, 40.19° E, geographic, 12.42° S, magnetic) during 2000 - 2014 were used. Ionospheric irregularities at scale- lengths of a few kilometers and ˜400 m were represented with the rate of change of TEC index (ROTI). The inputs for the models are the local time, solar flux index, Auroral Electrojet index, day of the year, and the Dst index, while the output is the median ROTI during these given conditions. To develop the models, the ROTI index values were binned based on the input parameters and cubic B splines were then fitted to the binned data. Developed models using data over NKLG and MAL2 were validated with independent data over stations within 510 km and 680 km radius, respectively. The models captured the enhancements and inhibitions of the occurrence of the ionospheric irregularities during the storm period. The models even emulated these patterns in the various seasons, during medium and high solar activity conditions. The correlation coefficients for the validations were statistically significant and ranged from 0.58 - 0.73, while the percentage of the variance in the observed data explained by the modelled data ranged from 34 - 53.

  7. Establishing a Functional Link Between African Dust and Region-wide Coral Reef Decline

    NASA Astrophysics Data System (ADS)

    Hayes, M. L.; Barber, R. T.

    2003-12-01

    For nearly thirty years, coral reefs in the Western Atlantic and Caribbean basin have experienced historically unprecedented declines. Algal blooms, mass coral bleaching, disease outbreaks and shifts in the dominance of benthic coral-competitors were first documented in the 1970s and have increased in frequency, intensity, variety and range over the past two decades. Recent studies of decreasing coral cover document regional losses averaging nearly 80% over this period. Here, we provide experimental evidence that increased supplies of iron-rich eolian dust from Africa to typically iron-poor marine environments throughout the region could have played a key role in these profound changes. Atmospheric inputs of "new" micronutrients, especially iron, have the potential to overcome limitations to the growth of opportunistic coral-competitors and the virulence of coral pathogens. Microcosm and mesocosm experiments with a putative bacterial pathogen of stony corals, Aurantimonas coralicida, and a temperate stony coral, Oculina arbuscula, provide a means to test the functional relationship between iron availability, microbial growth and coral health. Iron limitation of A. coralicida growth rates is readily induced by the addition of synthetic chelators such as 2,2' Dipyridyl to bacterial cultures at relatively low concentrations (e.g. 10 μ M). This growth limitation is reversed by 100 nM over-enrichments of pure reagent-grade iron as well as iron-rich "synthetic dust" derived from African lake-bed sediments. The Chrome-azurol S assay demonstrates that A. coralicida also synthesizes high-affinity iron-capture mechanisms (i.e. siderophores) that may serve as critical determinants of virulence. Finally, our experimental mesocosms are based on oligotrophic Mediterranean seawater and permit controlled experimentation under relatively low iron ( ˜5 nM) conditions. Using this system, denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified ribosomal DNA

  8. Modelling the probability of ionospheric irregularity occurrence over African low latitude region

    NASA Astrophysics Data System (ADS)

    Mungufeni, Patrick; Jurua, Edward; Bosco Habarulema, John; Anguma Katrini, Simon

    2015-06-01

    This study presents models of geomagnetically quiet time probability of occurrence of ionospheric irregularities over the African low latitude region. GNSS-derived ionospheric total electron content data from Mbarara, Uganda (0.60°S, 30.74°E, geographic, 10.22°S, magnetic) and Libreville, Gabon (0.35°N, 9.68°E, geographic, 8.05°S, magnetic) during the period 2001-2012 were used. First, we established the rate of change of total electron content index (ROTI) value associated with background ionospheric irregularity over the region. This was done by analysing GNSS carrier-phases at L-band frequencies L1 and L2 with the aim of identifying cycle slip events associated with ionospheric irregularities. We identified at both stations a total of 699 events of cycle slips. The corresponding median ROTI value at the epochs of the cycle slip events was 0.54 TECU/min. The probability of occurrence of ionospheric irregularities associated with ROTI ≥ 0.5 TECU / min was then modelled by fitting cubic B-splines to the data. The aspects the model captured included diurnal, seasonal, and solar flux dependence patterns of the probability of occurrence of ionospheric irregularities. The model developed over Mbarara was validated with data over Mt. Baker, Uganda (0.35°N, 29.90°E, geographic, 9.25°S, magnetic), Kigali, Rwanda (1.94°S, 30.09°E, geographic, 11.62°S, magnetic), and Kampala, Uganda (0.34°N, 32.60°E, geographic, 9.29°S, magnetic). For the period validated at Mt. Baker (approximately, 137.64 km, north west), Kigali (approximately, 162.42 km, south west), and Kampala (approximately, 237.61 km, north east) the percentages of the number of errors (difference between the observed and the modelled probability of occurrence of ionospheric irregularity) less than 0.05 are 97.3, 89.4, and 81.3, respectively.

  9. Low latitude nighttime ionospheric vertical E × B drifts at African region

    NASA Astrophysics Data System (ADS)

    Adebesin, B. O.; Adeniyi, J. O.; Adimula, I. A.; Reinisch, B. W.

    2013-12-01

    The nighttime vertical E × B drifts velocities of the F2-region were inferred from the hourly hmF2 values obtained from ionosonde data over an African equatorial station, Ilorin (8.50oN, 4.68oE; dip lat. 2.95o) during period of low solar activity. For each season, the plasma drift Vz is characterized by an evening upward enhancement, then by a downward reversal at 1900 LT till around 0000 LT, except for June solstice. This was explained using the Rayleigh-Taylor (R-T) instability mechanism. The occasional drift differences in Vz obtained by inferred and direct measurement over Ilorin and Jicamarca, respectively are reflective of the importance of chemistry and divergent transport system due to both the E region electric and magnetic fields instead of simple motions. The pre-reversal enhancement (PRE) magnitude is higher during the equinoctial months than the solsticial months over Jicamarca, highest during December solstice and the equinoctial months over Ilorin, suggesting the dominance of higher E × B fountain during equinoxes at both stations. The lowest PRE magnitude was in June solstice. The appearance of post-noon peak in NmF2 around 1700 LT is highest during the equinoctial months and lowest during the solsticial period. A general sharp drop in NmF2 around 1800 LT is distinct immediately after sunset, lowest during June solstice and highest in March equinox. Our result suggests that between 0930 and 2100 LT, the general theory that vertical drifts obtained by digisonde measurements only match the E × B drift if the F layer is higher than 300 km is reliable, but does not hold for the nighttime period of 2200-0600 LT under condition of solar minima. Hence, the condition may not be sufficient for the representation of vertical plasma drift at nighttime during solar minima. This assertion may still be tentative, as more equatorial stations needed to be studied for better confirmation.

  10. Global and Regional-scale Sst Variability and West African Monsoon. The Role of The Indian Ocean : A Numerical Study

    NASA Astrophysics Data System (ADS)

    Trzaska, S.; Fontaine, B.; Janicot, S.

    Interannual to decadal variability of the West African Monsoon has been commonly linked to Tropical Atlantic and Pacific SST variabilities (so called "Atlantic Dipole" and ENSO). Tropical Atlantic is thought to affect West African Monsoon via modi- fication of low-level thermal gradients driving the monsoon thus the location of the rainbelt over the continent. Warm events in the easten Pacific may affect it via up- per level zonal circulation and eventual subsidence over West Africa. However the teleconnections seem to have modified through time : main association with tropi- cal Atlantic during 50's and 60's i.e. the wetter period vs stronger association with ENSO and relative disconnection with tropical Atlantic during recent, dry decades. The role of the Indian Ocean has not been much investigated so far. The variability of this basin is dominated by a slow warming trend which compares well with the global warming. This study is aimed at investigating the possible effects of the Indian Ocean warming on the West African Monsoon dynamics and its teleconnections to ENSO and Tropical Atlantic. It is shown that this warming can potentially modify circulation anomalies related to ENSO in the Atlantic-African region by limiting the zonal extent of the zonal circulation anomalies and shifting the main subsidence branch to Africa and central Atlantic. In non-ENSO case monsoon circulation seems also to have more zonal orientation. The results are documented in the divergent circulation frame since it allows to unify a regional view of the monsoon as a meridional overturning with the global effects of ENSO in the zonal circulation. Modifications in the low-level moisture flux are also presented.

  11. Early Holocenic and Historic mtDNA African Signatures in the Iberian Peninsula: The Andalusian Region as a Paradigm

    PubMed Central

    Hernández, Candela L.; Soares, Pedro; Dugoujon, Jean M.; Novelletto, Andrea; Rodríguez, Juan N.; Rito, Teresa; Oliveira, Marisa; Melhaoui, Mohammed; Baali, Abdellatif; Pereira, Luisa; Calderón, Rosario

    2015-01-01

    Determining the timing, identity and direction of migrations in the Mediterranean Basin, the role of “migratory routes” in and among regions of Africa, Europe and Asia, and the effects of sex-specific behaviors of population movements have important implications for our understanding of the present human genetic diversity. A crucial component of the Mediterranean world is its westernmost region. Clear features of transcontinental ancient contacts between North African and Iberian populations surrounding the maritime region of Gibraltar Strait have been identified from archeological data. The attempt to discern origin and dates of migration between close geographically related regions has been a challenge in the field of uniparental-based population genetics. Mitochondrial DNA (mtDNA) studies have been focused on surveying the H1, H3 and V lineages when trying to ascertain north-south migrations, and U6 and L in the opposite direction, assuming that those lineages are good proxies for the ancestry of each side of the Mediterranean. To this end, in the present work we have screened entire mtDNA sequences belonging to U6, M1 and L haplogroups in Andalusians—from Huelva and Granada provinces—and Moroccan Berbers. We present here pioneer data and interpretations on the role of NW Africa and the Iberian Peninsula regarding the time of origin, number of founders and expansion directions of these specific markers. The estimated entrance of the North African U6 lineages into Iberia at 10 ky correlates well with other L African clades, indicating that U6 and some L lineages moved together from Africa to Iberia in the Early Holocene. Still, founder analysis highlights that the high sharing of lineages between North Africa and Iberia results from a complex process continued through time, impairing simplistic interpretations. In particular, our work supports the existence of an ancient, frequently denied, bridge connecting the Maghreb and Andalusia. PMID:26509580

  12. Early Holocenic and Historic mtDNA African Signatures in the Iberian Peninsula: The Andalusian Region as a Paradigm.

    PubMed

    Hernández, Candela L; Soares, Pedro; Dugoujon, Jean M; Novelletto, Andrea; Rodríguez, Juan N; Rito, Teresa; Oliveira, Marisa; Melhaoui, Mohammed; Baali, Abdellatif; Pereira, Luisa; Calderón, Rosario

    2015-01-01

    Determining the timing, identity and direction of migrations in the Mediterranean Basin, the role of "migratory routes" in and among regions of Africa, Europe and Asia, and the effects of sex-specific behaviors of population movements have important implications for our understanding of the present human genetic diversity. A crucial component of the Mediterranean world is its westernmost region. Clear features of transcontinental ancient contacts between North African and Iberian populations surrounding the maritime region of Gibraltar Strait have been identified from archeological data. The attempt to discern origin and dates of migration between close geographically related regions has been a challenge in the field of uniparental-based population genetics. Mitochondrial DNA (mtDNA) studies have been focused on surveying the H1, H3 and V lineages when trying to ascertain north-south migrations, and U6 and L in the opposite direction, assuming that those lineages are good proxies for the ancestry of each side of the Mediterranean. To this end, in the present work we have screened entire mtDNA sequences belonging to U6, M1 and L haplogroups in Andalusians--from Huelva and Granada provinces--and Moroccan Berbers. We present here pioneer data and interpretations on the role of NW Africa and the Iberian Peninsula regarding the time of origin, number of founders and expansion directions of these specific markers. The estimated entrance of the North African U6 lineages into Iberia at 10 ky correlates well with other L African clades, indicating that U6 and some L lineages moved together from Africa to Iberia in the Early Holocene. Still, founder analysis highlights that the high sharing of lineages between North Africa and Iberia results from a complex process continued through time, impairing simplistic interpretations. In particular, our work supports the existence of an ancient, frequently denied, bridge connecting the Maghreb and Andalusia. PMID:26509580

  13. The burden of natural and technological disaster-related mortality on gross domestic product (GDP) in the WHO African region.

    PubMed

    Kirigia, Joses M; Sambo, Luis G; Aldis, W; Mwabu, Germano M

    2002-01-01

    The WHO Africa region has the highest disaster mortality rate compared to the other five regions of the organization. Those deaths are hypothesized to have significantly negative effect on per capita gross domestic product (GDP). The objective of this study was to estimate the loss in GDP attributable to natural and technological disaster-related mortality in the WHO African Region. We estimated the impact of disaster-related mortality on GDP using double-log econometric model and cross-sectional data (from the UNDP and the World Bank publications) on 45 out of 46 countries in the WHO African Region. The coefficients for capital (K), educational enrolment (EN), life expectancy (LE) and exports (X) had a positive sign; while imports (M) and disaster mortality (DS) were found to impact negatively on GDP. The abovementioned explanatory variables were found to have statistically significant effect on GDP at 5% level in a t-distribution test. Disaster mortality of a single person was found to reduce GDP by US$0.018. We have demonstrated that disaster mortality has a significant negative effect on GDP. Thus, as policy-makers strive to increase GDP through capital investment, export promotion and increase in educational enrolment, they should always recall that investments in strengthening national capacity to mitigate the effects of national disasters expeditiously and effectively shall yield significant economic returns. PMID:17298162

  14. Seismicity Patterns and Magmatic Processes in the Rwenzori Region, East-African Rift

    NASA Astrophysics Data System (ADS)

    Lindenfeld, M.; Rumpker, G.; Schmeling, H.; Wallner, H.

    2010-12-01

    The 5000m high Rwenzori Mountains are situated within the western branch of the East African Rift System (EARS), at the border between Uganda and the Democratic Republic of Congo. They represent a basement block located within the rift valley whose origin and relation to the evolution of the EARS are highly puzzling. During a recent seismological campaign we located more than 800 earthquakes per month with magnitudes ranging from 0.5 to 5.1. Vertical sections across the northern parts of the Rwenzoris show, that west of the mountains (towards the rift valley) the focal depths range from 10 to 20 km, whereas the hypocentres go as deep as 30 km on the eastern side. This is in good agreement with Moho-depths derived from receiver functions and implies that all of these events are located within the crust. However, about 30 km east of the northern mountain ridge we located a cluster of 7 events that exhibit an anomalous depth of about 60 km. We can confidently locate these earthquakes within the mantle lithosphere beneath the rift. The existence of earthquakes at this depth is enigmatic, especially within a rifting regime were one expects hot and weak material relatively close to the surface. We think that these events are possibly related to the evolution of the Rwenzori Mountains. A recent hypothesis to explain the extreme uplift of the Rwenzori Mountains is rift induced delamination (RID) of mantle lithosphere. Here we show that the RID-process is indeed capable of explaining the seismic energy release in the mantle. However, in view of the specific hypocentral location of the event cluster, magmatic impregnation processes associated with dyke propagation into the mantle lithosphere may be a more realistic cause for seismic radiation at the observed depth. Crustal earthquakes northeast of the Rwenzori area are relocated with a double-difference algorithm to improve the spatial resolution of seismicity pattern. Several event clusters in the vicinity of the Fort

  15. Explaining the Ordinary Magic of Stable African Multilingualism in the Vaal Triangle Region in South Africa

    ERIC Educational Resources Information Center

    Coetzee-Van Rooy, Susan

    2014-01-01

    The academic and public debates about language maintenance and language shift in the post-1994 South Africa distract attention from the more productive and important endeavour of explaining the nature of the multilingualism observed among users of African languages in urban contexts. An explanation for this phenomenon is offered here, based on…

  16. Assessment of uncertainties in the response of the African monsoon precipitation to land use change simulated by a regional model

    SciTech Connect

    Hagos, Samson M.; Leung, Lai-Yung Ruby; Xue, Yongkang; Boone, Aaron; de Sales, Fernando; Neupane, Naresh; Huang, Maoyi; Yoon, Jin -Ho

    2014-02-22

    Land use and land cover over Africa have changed substantially over the last sixty years and this change has been proposed to affect monsoon circulation and precipitation. This study examines the uncertainties on the effect of these changes on the African Monsoon system and Sahel precipitation using an ensemble of regional model simulations with different combinations of land surface and cumulus parameterization schemes. Furthermore, the magnitude of the response covers a broad range of values, most of the simulations show a decline in Sahel precipitation due to the expansion of pasture and croplands at the expense of trees and shrubs and an increase in surface air temperature.

  17. Impact of GCM boundary forcing on regional climate modeling of West African summer monsoon precipitation and circulation features

    NASA Astrophysics Data System (ADS)

    Kebe, Ibourahima; Sylla, Mouhamadou Bamba; Omotosho, Jerome Adebayo; Nikiema, Pinghouinde Michel; Gibba, Peter; Giorgi, Filippo

    2016-05-01

    In this study, the latest version of the International Centre for Theoretical Physics Regional Climate Model (RegCM4) driven by three CMIP5 Global Climate Models (GCMs) is used at 25 km grid spacing over West Africa to investigate the impact of lateral boundary forcings on the simulation of monsoon precipitation and its relationship with regional circulation features. We find that the RegCM4 experiments along with their multimodel ensemble generally reproduce the location of the main precipitation characteristics over the region and improve upon the corresponding driving GCMs. However, the provision of different forcing boundary conditions leads to substantially different precipitation magnitudes and spatial patterns. For instance, while RegCM4 nested within GFDL-ESM-2M and HadGEM2-ES exhibits some underestimations of precipitation and an excessively narrow Intertropical Convergence Zone, the MPI-ESM-MR driven run produces precipitation spatial distribution and magnitudes more similar to observations. Such a superior performance originates from a much better simulation of the interactions between baroclinicity, temperature gradient and African Easterly Jet along with an improved connection between the Isentropic Potential Vorticity, its gradient and the African Easterly Waves dynamics. We conclude that a good performing GCM in terms of monsoon dynamical features (in this case MPI-ESM-MR) is needed to drive RCMs in order to achieve a better representation of the West Africa summer monsoon precipitation.

  18. The mitochondrial landscape of African Americans: An examination of more than 2500 control region haplotypes from 22 U.S. locations.

    PubMed

    Scheible, M; Just, R; Sturk-Andreaggi, K; Saunier, J; Parson, W; Parsons, T; Coble, M; Irwin, J

    2016-05-01

    The mitochondrial DNA (mtDNA) control region (16024-576) was Sanger-sequenced for a total of 2563 self-identified African Americans, using automated processing techniques and data review standards exceeding guidelines for forensic applications. Genetic diversity ranged from 0.9952 to 0.9998 in 22 population samples from 20 different states. Haplogroups of African ancestry, found in 82.48% of individuals overall, were most concentrated in the Southeast U.S. and decreased to the north and west. West African and West Central African haplotypes were well-represented in the population samples, especially in the southern U.S. states, while East African haplogroups were observed in low-frequency clusters in a handful of locations across the country. East Asian, Native American, and West Eurasian admixture was present in 3.16%, 2.93%, and 11.43% of samples, respectively. While some geographic substructure was detected across the population samples as clines in admixture frequencies, 20 of the 22 population samples were found to be statistically indistinguishable by pairwise comparisons and AMOVA calculations. Datasets from Hawaii and Idaho, however, were clear outliers. Overall, these more than 2500 control region sequences represent the most comprehensive regional sampling of African American mtDNA diversity to date, and are suitable for use in a forensic mtDNA database. The population data are made available via EMPOP (www.empop.org) and GenBank. PMID:26919661

  19. Malaria control in the African Region: perceptions and viewspoints on proceedings of the Africa Leaders Malaria Alliance (ALMA)

    PubMed Central

    2011-01-01

    Union and regional economic communities to address the cross-border dimension of malaria control. It was agreed that countries needed to secure adequate domestic and external funding for sustained commitment to malaria elimination; strengthen national malaria control programmes in the context of broader health system strengthening; ensure free access to long-lasting insecticide treated nets and malaria diagnosis and treatment for vulnerable groups; strengthen human resource capacity at central, district and community levels; and establish strong logistics, information and surveillance systems. Conclusion It is critically important for countries to have a clear vision and strategy for malaria elimination; effective leadership of national malaria control programmes; draw lessons from other African countries that have succeeded to dramatically reduce the burden of malaria; and sustain funding and ongoing interventions. PMID:21810213

  20. Phylogenetic relations of humans and African apes from DNA sequences in the Psi eta-globin region

    SciTech Connect

    Miyamoto, M.M.; Slightom, J.L.; Goodman, M.

    1987-10-16

    Sequences from the upstream and downstream flanking DNA regions of the Psi eta-globin locus in Pan troglodytes (common chimpanzee), Gorilla gorilla (gorilla), and Pongo pygmaeus (orangutan, the closest living relative to Homo, Pan, and Gorilla) provided further data for evaluating the phylogenetic relations of humans and African apes. These newly sequenced orthologs (an additional 4.9 kilobase pairs (kbp) for each species) were combined with published Psi eta-gene sequences and then compared to the same orthologous stretch (a continuous 7.1-kbp region) available for humans. Phylogenetic analysis of these nucleotide sequences by the parsimony method indicated (i) that human and chimpanzee are more closely related to each other than either is to gorilla and (ii) that the slowdown in the rate of sequence evolution evident in higher primates is especially pronounced in humans. These results indicate that features unique to African apes (but not to humans) are primitive and that even local molecular clocks should be applied with caution.

  1. Ocean Pollution as a Result of Onshore Offshore Petroleum Activities in the African Gulf of Guinea Region

    NASA Astrophysics Data System (ADS)

    Abubakar, B.

    2007-05-01

    increasing cases of pollution of farmlands, rivers, wells and the environment in general. Apart from all these, what is even becoming more worrisome is that none of all these oil firms operating in the region is able to account on how it disposes its industrial toxic waste generated as a result of its industrial activities within the region. Finally Geological strata are adversely destroyed by seismographic activities, Sea creatures are destroyed by oil pollution and Means of livelihood of revering dwellers are often threatened by pollution. RECOMMENDATIONS After identifying how the pollution in the Gulf of Guinea region is increasing in relation to the increasing petroleum activities, I have come up with the following suggestions/recommendations. 1. AFRICAN UNION RESOLUTION The Organization of the Petroleum Exporting Countries (OPEC) in conjunction with the International Atomic Energy Agency (IAEA) should use their capacity to be able to influence the African Union (AU) to pass a resolution banning the illegal dumping of radioactive waste, Gas flaring and Costal bunkering in this part of the world. 2. RESEARCH AND INVESTIGATION The Organization of the Petroleum Exporting Countries, in conjunction with the United Nations Environmental Agency, the International Atomic Energy Agency and with the corporation of the African Union should send team of researchers to come and investigate this trend on petroleum pollution in the Gulf of Guinea region and proffer possible solutions in checking the menace.

  2. Solar quiet day ionospheric source current in the West African region

    PubMed Central

    Obiekezie, Theresa N.; Okeke, Francisca N.

    2012-01-01

    The Solar Quiet (Sq) day source current were calculated using the magnetic data obtained from a chain of 10 magnetotelluric stations installed in the African sector during the French participation in the International Equatorial Electrojet Year (IEEY) experiment in Africa. The components of geomagnetic field recorded at the stations from January–December in 1993 during the experiment were separated into the source and (induced) components of Sq using Spherical Harmonics Analysis (SHA) method. The range of the source current was calculated and this enabled the viewing of a full year’s change in the source current system of Sq. PMID:25685434

  3. Solar quiet day ionospheric source current in the West African region.

    PubMed

    Obiekezie, Theresa N; Okeke, Francisca N

    2013-05-01

    The Solar Quiet (Sq) day source current were calculated using the magnetic data obtained from a chain of 10 magnetotelluric stations installed in the African sector during the French participation in the International Equatorial Electrojet Year (IEEY) experiment in Africa. The components of geomagnetic field recorded at the stations from January-December in 1993 during the experiment were separated into the source and (induced) components of Sq using Spherical Harmonics Analysis (SHA) method. The range of the source current was calculated and this enabled the viewing of a full year's change in the source current system of Sq. PMID:25685434

  4. Managed European-Derived Honey Bee, Apis mellifera sspp, Colonies Reduce African-Matriline Honey Bee, A. m. scutellata, Drones at Regional Mating Congregations.

    PubMed

    Mortensen, Ashley N; Ellis, James D

    2016-01-01

    African honey bees (Apis mellifera scutellata) dramatically changed the South American beekeeping industry as they rapidly spread through the Americas following their introduction into Brazil. In the present study, we aimed to determine if the management of European-derived honey bees (A. mellifera sspp.) could reduce the relative abundance of African-matriline drones at regional mating sites known as drone congregation areas (DCAs). We collected 2,400 drones at six DCAs either 0.25 km or >2.8 km from managed European-derived honey bee apiaries. The maternal ancestry of each drone was determined by Bgl II enzyme digestion of an amplified portion of the mitochondrial Cytochrome b gene. Furthermore, sibship reconstruction via nuclear microsatellites was conducted for a subset of 1,200 drones to estimate the number of colonies contributing drones to each DCA. Results indicate that DCAs distant to managed European apiaries (>2.8 km) had significantly more African-matriline drones (34.33% of the collected drones had African mitochondrial DNA) than did DCAs close (0.25 km) to managed European apiaries (1.83% of the collected drones had African mitochondrial DNA). Furthermore, nuclear sibship reconstruction demonstrated that the reduction in the proportion of African matriline drones at DCAs near apiaries was not simply an increase in the number of European matriline drones at the DCAs but also the result of fewer African matriline colonies contributing drones to the DCAs. Our data demonstrate that the management of European honey bee colonies can dramatically influence the proportion of drones with African matrilines at nearby drone congregation areas, and would likely decreasing the probability that virgin European queens will mate with African drones at those drone congregation areas. PMID:27518068

  5. Patterns of sequence divergence and evolution of the S orthologous regions between Asian and African cultivated rice species.

    PubMed

    Guyot, Romain; Garavito, Andrea; Gavory, Frédérick; Samain, Sylvie; Tohme, Joe; Ghesquière, Alain; Lorieux, Mathias

    2011-01-01

    A strong postzygotic reproductive barrier separates the recently diverged Asian and African cultivated rice species, Oryza sativa and O. glaberrima. Recently a model of genetic incompatibilities between three adjacent loci: S(1)A, S(1) and S(1)B (called together the S(1) regions) interacting epistatically, was postulated to cause the allelic elimination of female gametes in interspecific hybrids. Two candidate factors for the S(1) locus (including a putative F-box gene) were proposed, but candidates for S(1)A and S(1)B remained undetermined. Here, to better understand the basis of the evolution of regions involved in reproductive isolation, we studied the genic and structural changes accumulated in the S(1) regions between orthologous sequences. First, we established an 813 kb genomic sequence in O. glaberrima, covering completely the S(1)A, S(1) and the majority of the S(1)B regions, and compared it with the orthologous regions of O. sativa. An overall strong structural conservation was observed, with the exception of three isolated regions of disturbed collinearity: (1) a local invasion of transposable elements around a putative F-box gene within S(1), (2) the multiple duplication and subsequent divergence of the same F-box gene within S(1)A, (3) an interspecific chromosomal inversion in S(1)B, which restricts recombination in our O. sativa×O. glaberrima crosses. Beside these few structural variations, a uniform conservative pattern of coding sequence divergence was found all along the S(1) regions. Hence, the S(1) regions have undergone no drastic variation in their recent divergence and evolution between O. sativa and O. glaberrima, suggesting that a small accumulation of genic changes, following a Bateson-Dobzhansky-Muller (BDM) model, might be involved in the establishment of the sterility barrier. In this context, genetic incompatibilities involving the duplicated F-box genes as putative candidates, and a possible strengthening step involving the

  6. Patterns of Sequence Divergence and Evolution of the S1 Orthologous Regions between Asian and African Cultivated Rice Species

    PubMed Central

    Gavory, Frédérick; Samain, Sylvie; Tohme, Joe; Ghesquière, Alain; Lorieux, Mathias

    2011-01-01

    A strong postzygotic reproductive barrier separates the recently diverged Asian and African cultivated rice species, Oryza sativa and O. glaberrima. Recently a model of genetic incompatibilities between three adjacent loci: S1A, S1 and S1B (called together the S1 regions) interacting epistatically, was postulated to cause the allelic elimination of female gametes in interspecific hybrids. Two candidate factors for the S1 locus (including a putative F-box gene) were proposed, but candidates for S1A and S1B remained undetermined. Here, to better understand the basis of the evolution of regions involved in reproductive isolation, we studied the genic and structural changes accumulated in the S1 regions between orthologous sequences. First, we established an 813 kb genomic sequence in O. glaberrima, covering completely the S1A, S1 and the majority of the S1B regions, and compared it with the orthologous regions of O. sativa. An overall strong structural conservation was observed, with the exception of three isolated regions of disturbed collinearity: (1) a local invasion of transposable elements around a putative F-box gene within S1, (2) the multiple duplication and subsequent divergence of the same F-box gene within S1A, (3) an interspecific chromosomal inversion in S1B, which restricts recombination in our O. sativa×O. glaberrima crosses. Beside these few structural variations, a uniform conservative pattern of coding sequence divergence was found all along the S1 regions. Hence, the S1 regions have undergone no drastic variation in their recent divergence and evolution between O. sativa and O. glaberrima, suggesting that a small accumulation of genic changes, following a Bateson-Dobzhansky-Muller (BDM) model, might be involved in the establishment of the sterility barrier. In this context, genetic incompatibilities involving the duplicated F-box genes as putative candidates, and a possible strengthening step involving the chromosomal inversion might participate to

  7. Regional trade and the nutrition transition: opportunities to strengthen NCD prevention policy in the Southern African Development Community

    PubMed Central

    Thow, Anne Marie; Sanders, David; Drury, Eliza; Puoane, Thandi; Chowdhury, Syeda N.; Tsolekile, Lungiswa; Negin, Joel

    2015-01-01

    Background Addressing diet-related non-communicable diseases (NCDs) will require a multisectoral policy approach that includes the food supply and trade, but implementing effective policies has proved challenging. The Southern African Development Community (SADC) has experienced significant trade and economic liberalization over the past decade; at the same time, the nutrition transition has progressed rapidly in the region. This analysis considers the relationship between regional trade liberalization and changes in the food environment associated with poor diets and NCDs, with the aim of identifying feasible and proactive policy responses to support healthy diets. Design Changes in trade and investment policy for the SADC were documented and compared with time-series graphs of import data for soft drinks and snack foods to assess changes in imports and source country in relation to trade and investment liberalization. Our analysis focuses on regional trade flows. Results Diets and the burden of disease in the SADC have changed since the 1990s in parallel with trade and investment liberalization. Imports of soft drinks increased by 76% into SADC countries between 1995 and 2010, and processed snack foods by 83%. South Africa acts as a regional trade and investment hub; it is the major source of imports and investment related to these products into other SADC countries. At the same time, imports of processed foods and soft drinks from outside the region – largely from Asia and the Middle East – are increasing at a dramatic rate with soft drink imports growing by almost 1,200% and processed snack foods by 750%. Conclusions There is significant intra-regional trade in products associated with the nutrition transition; however, growing extra-regional trade means that countries face new pressures in implementing strong policies to prevent the increasing burden of diet-related NCDs. Implementation of a regional nutrition policy framework could complement the SADC

  8. Phylogenetic analysis of the polyprotein coding region of an infectious South African bursal disease virus (IBDV) strain.

    PubMed

    Vukea, Phillia R; Willows-Munro, Sandi; Horner, Roger F; Coetzer, Theresa H T

    2014-01-01

    Infectious bursal disease virus (IBDV) causes Gumboro disease, which is highly contagious and immunosuppressive in young chickens. A virulent form of IBDV reached South Africa in 1989 and to date there has been little molecular information available for this strain. In this study, the polyprotein coding region of the South African strain SA-KZN95 was sequenced and analysed along with 52 representative sequences of other serotype I and II strains. We explored the relative impact of recombination on phylogenetic reconstruction using a multidimensional scaling approach. Phylogenetic analyses consistently placed the South African isolate within the very virulent IBDV clade. Selection analyses were also conducted to identify evolutionarily relevant amino acid residues. Previously, 19 residues in the polyprotein were shown to be potentially diagnostic for the different IBDV pathotypes. This study identified an additional two unique residues in the polyprotein which may be used as genetic signatures in future viral identifications. Better strain identification would aid in the development and application of vaccines. PMID:24291011

  9. Protocol to the African Charter on the Rights of Women: implications for access to abortion at the regional level.

    PubMed

    Ngwena, Charles G

    2010-08-01

    Article 14(2)(c) of the Protocol to the African Charter on the Rights of Women enjoins States Parties to take appropriate measures "to protect the reproductive rights of women by authorising medical abortion in cases of sexual assault, rape, incest, and where continued pregnancy endangers the mental and physical health of the mother or the life of the mother or the foetus." This paper considers the implications of Article 14 for access to safe, legal abortion. It is submitted that Article 14 has the potential to impact positively on regional abortion law, policy, and practice in 3 main areas. First, it takes forward the global consensus on combating abortion as a major public health danger. Second, it provides African countries with not just an incentive, but also an imperative for reforming abortion laws in a transparent manner. Third, if implemented in the context of a treaty that centers on the equality and non-discrimination of women, Article 14 has the potential to contribute toward transforming access to abortion from a crime and punishment model to a reproductive health model. PMID:20546748

  10. West African monsoon intraseasonal activity and its daily precipitation indices in regional climate models: diagnostics and challenges

    NASA Astrophysics Data System (ADS)

    Poan, E. D.; Gachon, P.; Dueymes, G.; Diaconescu, E.; Laprise, R.; Seidou Sanda, I.

    2016-02-01

    The West African monsoon intraseasonal variability has huge socio-economic impacts on local populations but understanding and predicting it still remains a challenge for the weather prediction and climate scientific community. This paper analyses an ensemble of simulations from six regional climate models (RCMs) taking part in the coordinated regional downscaling experiment, the ECMWF ERA-Interim reanalysis (ERAI) and three satellite-based and observationally-constrained daily precipitation datasets, to assess the performance of the RCMs with regard to the intraseasonal variability. A joint analysis of seasonal-mean precipitation and the total column water vapor (also called precipitable water—PW) suggests the existence of important links at different timescales between these two variables over the Sahel and highlights the relevance of using PW to follow the monsoon seasonal cycle. RCMs that fail to represent the seasonal-mean position and amplitude of the meridional gradient of PW show the largest discrepancies with respect to seasonal-mean observed precipitation. For both ERAI and RCMs, spectral decompositions of daily PW as well as rainfall show an overestimation of low-frequency activity (at timescales longer than 10 days) at the expense of the synoptic (timescales shorter than 10 days) activity. Consequently, the effects of the African Easterly Waves and the associated mesoscale convective systems are substantially underestimated, especially over continental regions. Finally, the study investigates the skill of the models with respect to hydro-climatic indices related to the occurrence, intensity and frequency of precipitation events at the intraseasonal scale. Although most of these indices are generally better reproduced with RCMs than reanalysis products, this study indicates that RCMs still need to be improved (especially with respect to their subgrid-scale parameterization schemes) to be able to reproduce the intraseasonal variance spectrum adequately.

  11. How strong ist the impact of changing topography of the East African Rift System on regional climate?

    NASA Astrophysics Data System (ADS)

    Prömmel, Kerstin; Kaspar, Frank; Cubasch, Ulrich

    2010-05-01

    The evolution of the East African Rift System (EARS) leads to a topography change at the surface and the impact of this change on climate in this region can easily be analysed with climate models. In the present study both global and regional climate models are applied. The global climate model is the coupled atmosphere ocean general circulation model ECHO-G and the regional climate model is the non-hydrostatic CLM, which is the climate version of the numerical weather prediction model of the German Meterorological Service. At the lateral boundaries the regional model is driven by the simulations performed with the global model. Different topographical situations representing possible conditions in the past, are simulated with the global and the regional climate model. One assumption affects only the highest peaks of the EARS south of the Turkana Channel by reducing them to 1200 m. The other assumptions affect a much larger area covering the whole of Southern and Eastern Africa. Over this region topography is reduced by 25%, 50%, 75% and 95%. These different topography reductions have an impact on circulation and therefore also on moisture transport. This leads to changes in the precipitation patterns over Africa. One strong effect is the decrease in orographic precipitation windward of the mountains. Wetter conditions can be found over the east coast of Africa, where moisture is transported from the Indian Ocean farther into the continent due to the lower barrier. Both global and regional models show similar results on the continental scale, however the results of the regional model are much more detailed due to the higher horizontal resolution (50 km) compared to the global model (~350 km).

  12. A review of groundwater recharge estimation in humid and semi-arid African regions

    NASA Astrophysics Data System (ADS)

    Chung, Il-Moon; Kim, Nam Won

    2016-04-01

    For the review of African recharge estimation, the distinct methods such as the geochemical approach, a method using groundwater level data, the streamflow method, and the water balance methods were first outlined. The major challenge of an African recharge study is the lack of basic data. Thus, this work suggests how to deal with this limitation and from future perspective using recently developed technologies such as RS, GIS, etc. With the rapid growth of information technology, more and more data, in terms of both volume and variety, are expected to be made available on the internet in the near future. RS technology has a great potential to revolutionize the groundwater development and management in the future by providing unique and completely new hydrological and hydrogeological data. However, at present, the RS data should be considered along with the conventional field data. In spite of the weaknesses of water balance methods in semi-arid areas, recently developed water balance methods combined with GIS technology are powerful tools for estimating groundwater re-charge, when spatial-temporal variability of components in water balance is taken into account (Lerner et al., 1990; De Vries and Simmers, 2002; Eilers et al., 2007).When enough data sets are available, integrated surface-groundwater modeling is recommended for more accurate estimation of groundwater recharge and discharge. Acknowledgements This work was supported by a grant(14RDRP-B076275-01-000000) from Infrastructure and transportation technology promotion research Program funded by the Ministry of Land, Infrastructure and Transport of Korean government.

  13. Managed European-Derived Honey Bee, Apis mellifera sspp, Colonies Reduce African-Matriline Honey Bee, A. m. scutellata, Drones at Regional Mating Congregations

    PubMed Central

    Mortensen, Ashley N.; Ellis, James D.

    2016-01-01

    African honey bees (Apis mellifera scutellata) dramatically changed the South American beekeeping industry as they rapidly spread through the Americas following their introduction into Brazil. In the present study, we aimed to determine if the management of European-derived honey bees (A. mellifera sspp.) could reduce the relative abundance of African-matriline drones at regional mating sites known as drone congregation areas (DCAs). We collected 2,400 drones at six DCAs either 0.25 km or >2.8 km from managed European-derived honey bee apiaries. The maternal ancestry of each drone was determined by Bgl II enzyme digestion of an amplified portion of the mitochondrial Cytochrome b gene. Furthermore, sibship reconstruction via nuclear microsatellites was conducted for a subset of 1,200 drones to estimate the number of colonies contributing drones to each DCA. Results indicate that DCAs distant to managed European apiaries (>2.8 km) had significantly more African−matriline drones (34.33% of the collected drones had African mitochondrial DNA) than did DCAs close (0.25 km) to managed European apiaries (1.83% of the collected drones had African mitochondrial DNA). Furthermore, nuclear sibship reconstruction demonstrated that the reduction in the proportion of African matriline drones at DCAs near apiaries was not simply an increase in the number of European matriline drones at the DCAs but also the result of fewer African matriline colonies contributing drones to the DCAs. Our data demonstrate that the management of European honey bee colonies can dramatically influence the proportion of drones with African matrilines at nearby drone congregation areas, and would likely decreasing the probability that virgin European queens will mate with African drones at those drone congregation areas. PMID:27518068

  14. Five linkage regions each harbor multiple type 2 diabetes genes in the African American subset of the GENNID Study.

    PubMed

    Hasstedt, Sandra J; Highland, Heather M; Elbein, Steven C; Hanis, Craig L; Das, Swapan K

    2013-06-01

    We previously localized type 2 diabetes (T2D)-susceptibility genes to five chromosomal regions through a genome-wide linkage scan of T2D and age of diagnosis (AOD) in the African American subset of the GENNID sample. To follow up these findings, we repeated the linkage and association analysis using genotypes on an additional 9203 fine-mapping single nucleotide polymorphisms (SNPs) selected to tag genes under the linkage peaks. In each of the five regions, we confirmed linkage and inferred the presence of ≥2 susceptibility genes. The evidence of multiple susceptibility genes consisted of: (1) multiple linkage peaks in four of the five regions; and (2) association of T2D and AOD with SNPs within ≥2 genes in every region. The associated genes included 3 previously reported to associate with T2D or related traits (GRB10, NEDD4L, LIPG) and 24 novel candidate genes, including genes in lipid metabolism (ACOXL) and cell-cell and cell-matrix adhesion (MAGI2, CLDN4, CTNNA2). PMID:23552671

  15. Assessment of uncertainties in the response of the African monsoon precipitation to land use change simulated by a regional model

    DOE PAGESBeta

    Hagos, Samson M.; Leung, Lai-Yung Ruby; Xue, Yongkang; Boone, Aaron; de Sales, Fernando; Neupane, Naresh; Huang, Maoyi; Yoon, Jin -Ho

    2014-02-22

    Land use and land cover over Africa have changed substantially over the last sixty years and this change has been proposed to affect monsoon circulation and precipitation. This study examines the uncertainties on the effect of these changes on the African Monsoon system and Sahel precipitation using an ensemble of regional model simulations with different combinations of land surface and cumulus parameterization schemes. Furthermore, the magnitude of the response covers a broad range of values, most of the simulations show a decline in Sahel precipitation due to the expansion of pasture and croplands at the expense of trees and shrubsmore » and an increase in surface air temperature.« less

  16. Addressing the Issue of Gender Equity in the Presidency of the University System in the Southern African Development Community (SADC) Region

    ERIC Educational Resources Information Center

    Guramatunhu-Mudiwa, Precious

    2010-01-01

    The Southern African Development Community (SADC) is a regional economic grouping of 15 countries whose common vision is to promote economic, social and political development and growth. Arguably, sustainable growth can be realized if there is equal access to all positions of power and influence in the area, but an investigation of 117…

  17. African horse sickness: The potential for an outbreak in disease-free regions and current disease control and elimination techniques.

    PubMed

    Robin, M; Page, P; Archer, D; Baylis, M

    2016-09-01

    African horse sickness (AHS) is an arboviral disease of equids transmitted by Culicoides biting midges. The virus is endemic in parts of sub-Saharan Africa and official AHS disease-free status can be obtained from the World Organization for Animal Health on fulfilment of a number of criteria. AHS is associated with case fatality rates of up to 95%, making an outbreak among naïve horses both a welfare and economic disaster. The worldwide distributions of similar vector-borne diseases (particularly bluetongue disease of ruminants) are changing rapidly, probably due to a combination of globalisation and climate change. There is extensive evidence that the requisite conditions for an AHS epizootic currently exist in disease-free countries. In particular, although the stringent regulations enforced upon competition horses make them extremely unlikely to redistribute the virus, there are great concerns over the effects of illegal equid movement. An outbreak of AHS in a disease free region would have catastrophic effects on equine welfare and industry, particularly for international events such as the Olympic Games. While many regions have contingency plans in place to manage an outbreak of AHS, further research is urgently required if the equine industry is to avoid or effectively contain an AHS epizootic in disease-free regions. This review describes the key aspects of AHS as a global issue and discusses the evidence supporting concerns that an epizootic may occur in AHS free countries, the planned government responses, and the roles and responsibilities of equine veterinarians. PMID:27292229

  18. QTL Mapping in Three Rice Populations Uncovers Major Genomic Regions Associated with African Rice Gall Midge Resistance

    PubMed Central

    Semagn, Kassa; Sow, Mounirou; Nwilene, Francis; Kolade, Olufisayo; Bocco, Roland; Oyetunji, Olumoye; Mitchell-Olds, Thomas; Ndjiondjop, Marie-Noëlle

    2016-01-01

    African rice gall midge (AfRGM) is one of the most destructive pests of irrigated and lowland African ecologies. This study aimed to identify the quantitative trait loci (QTL) associated with AfRGM pest incidence and resistance in three independent bi-parental rice populations (ITA306xBW348-1, ITA306xTOG7106 and ITA306xTOS14519), and to conduct meta QTL (mQTL) analysis to explore whether any genomic regions are conserved across different genetic backgrounds. Composite interval mapping (CIM) conducted on the three populations independently uncovered a total of 28 QTLs associated with pest incidence (12) and pest severity (16). The number of QTLs per population associated with AfRGM resistance varied from three in the ITA306xBW348-1 population to eight in the ITA306xTOG7106 population. Each QTL individually explained 1.3 to 34.1% of the phenotypic variance. The major genomic region for AfRGM resistance had a LOD score and R2 of 60.0 and 34.1% respectively, and mapped at 111 cM on chromosome 4 (qAfrGM4) in the ITA306xTOS14519 population. The meta-analysis reduced the number of QTLs from 28 to 17 mQTLs, each explaining 1.3 to 24.5% of phenotypic variance, and narrowed the confidence intervals by 2.2 cM. There was only one minor effect mQTL on chromosome 1 that was common in the TOS14519 and TOG7106 genetic backgrounds; all other mQTLs were background specific. We are currently fine-mapping and validating the major effect genomic region on chromosome 4 (qAfRGM4). This is the first report in mapping the genomic regions associated with the AfRGM resistance, and will be highly useful for rice breeders. PMID:27508500

  19. QTL Mapping in Three Rice Populations Uncovers Major Genomic Regions Associated with African Rice Gall Midge Resistance.

    PubMed

    Yao, Nasser; Lee, Cheng-Ruei; Semagn, Kassa; Sow, Mounirou; Nwilene, Francis; Kolade, Olufisayo; Bocco, Roland; Oyetunji, Olumoye; Mitchell-Olds, Thomas; Ndjiondjop, Marie-Noëlle

    2016-01-01

    African rice gall midge (AfRGM) is one of the most destructive pests of irrigated and lowland African ecologies. This study aimed to identify the quantitative trait loci (QTL) associated with AfRGM pest incidence and resistance in three independent bi-parental rice populations (ITA306xBW348-1, ITA306xTOG7106 and ITA306xTOS14519), and to conduct meta QTL (mQTL) analysis to explore whether any genomic regions are conserved across different genetic backgrounds. Composite interval mapping (CIM) conducted on the three populations independently uncovered a total of 28 QTLs associated with pest incidence (12) and pest severity (16). The number of QTLs per population associated with AfRGM resistance varied from three in the ITA306xBW348-1 population to eight in the ITA306xTOG7106 population. Each QTL individually explained 1.3 to 34.1% of the phenotypic variance. The major genomic region for AfRGM resistance had a LOD score and R2 of 60.0 and 34.1% respectively, and mapped at 111 cM on chromosome 4 (qAfrGM4) in the ITA306xTOS14519 population. The meta-analysis reduced the number of QTLs from 28 to 17 mQTLs, each explaining 1.3 to 24.5% of phenotypic variance, and narrowed the confidence intervals by 2.2 cM. There was only one minor effect mQTL on chromosome 1 that was common in the TOS14519 and TOG7106 genetic backgrounds; all other mQTLs were background specific. We are currently fine-mapping and validating the major effect genomic region on chromosome 4 (qAfRGM4). This is the first report in mapping the genomic regions associated with the AfRGM resistance, and will be highly useful for rice breeders. PMID:27508500

  20. University as Regional Development Agent: A Counterfactual Analysis of an African University

    ERIC Educational Resources Information Center

    Fongwa, Samuel N.; Wangenge-Ouma, Gerald

    2015-01-01

    The contribution of universities to regional development has in the last few decades gained significant currency. Inter alia, this contribution has been through steered national, regional, and institutional policies aimed at enhancing national development, good governance, human capital creation and innovation in an increasing knowledge-dependent…

  1. Factors Associated with African-American Freshmen and Non-African-American Freshmen Retention and Graduation at a Predominantly White, Regional University

    ERIC Educational Resources Information Center

    Owens, Robert L., II

    2009-01-01

    The purpose of this study was to examine further, the factors at a Predominantly White College or University (PWCU) that may affect the first-year retention and six-year graduation of African-American (AA) and non-AA students. Biographical and descriptive data was obtained for each student entering Tennessee Technological University (TTU) from the…

  2. Plate Kinematic model of the NW Indian Ocean and derived regional stress history of the East African Margin

    NASA Astrophysics Data System (ADS)

    Tuck-Martin, Amy; Adam, Jürgen; Eagles, Graeme

    2015-04-01

    Starting with the break up of Gondwana, the northwest Indian Ocean and its continental margins in Madagascar, East Africa and western India formed by divergence of the African and Indian plates and were shaped by a complicated sequence of plate boundary relocations, ridge propagation events, and the independent movement of the Seychelles microplate. As a result, attempts to reconcile the different plate-tectonic components and processes into a coherent kinematic model have so far been unsatisfactory. A new high-resolution plate kinematic model has been produced in an attempt to solve these problems, using seafloor spreading data and rotation parameters generated by a mixture of visual fitting of magnetic isochron data and iterative joint inversion of magnetic isochron and fracture zone data. Using plate motion vectors and plate boundary geometries derived from this model, the first-order regional stress pattern was modelled for distinct phases of margin formation. The stress pattern is correlated with the tectono-stratigraphic history of related sedimentary basins. The plate kinematic model identifies three phases of spreading, from the Jurassic to the Paleogene, which resulted in the formation of three main oceanic basins. Prior to these phases, intracontinental 'Karoo' rifting episodes in the late Carboniferous to late Triassic had failed to break up Gondwana, but initiated the formation of sedimentary basins along the East African and West Madagascan margins. At the start of the first phase of spreading (183 to 133 Ma) predominantly NW - SE extension caused continental rifting that separated Madagascar/India/Antarctica from Africa. Maximum horizontal stresses trended perpendicular to the local plate-kinematic vector, and parallel to the rift axes. During and after continental break-up and subsequent spreading, the regional stress regime changed drastically. The extensional stress regime became restricted to the active spreading ridges that in turn adopted trends

  3. Variable light environments induce plastic spectral tuning by regional opsin coexpression in the African cichlid fish, Metriaclima zebra

    PubMed Central

    Dalton, Brian E.; Lu, Jessica; Leips, Jeff; Cronin, Thomas W.; Carleton, Karen L.

    2015-01-01

    Critical behaviors such as predation and mate choice often depend on vision. Visual systems are sensitive to the spectrum of light in their environment, which can vary extensively both within and among habitats. Evolutionary changes in spectral sensitivity contribute to divergence and speciation. Spectral sensitivity of the retina is primarily determined by visual pigments, which are opsin proteins bound to a chromophore. We recently discovered that photoreceptors in different regions of the retina, which view objects against distinct environmental backgrounds, coexpress different pairs of opsins in an African cichlid fish, Metriaclima zebra. This coexpression tunes the sensitivity of the retinal regions to the corresponding backgrounds and may aid detection of dark objects, such as predators. Although intraretinal regionalization of spectral sensitivity in many animals correlates with their light environments, it is unknown whether variation in the light environment induces developmentally plastic alterations of intraretinal sensitivity regions. Here, we demonstrate with fluorescent in situ hybridization and qPCR that the spectrum and angle of environmental light both influence the development of spectral sensitivity regions by altering the distribution and level of opsins across the retina. Normally M. zebra coexpresses LWS opsin with RH2Aα opsin in double cones of the ventral but not the dorsal retina. However, when illuminated from below throughout development, adult M. zebra coexpressed LWS and RH2Aα in double cones both dorsally and ventrally. Thus, environmental background spectra alter the spectral sensitivity pattern that develops across the retina, potentially influencing behaviors and related evolutionary processes such as courtship and speciation. PMID:26175094

  4. Variable light environments induce plastic spectral tuning by regional opsin coexpression in the African cichlid fish, Metriaclima zebra.

    PubMed

    Dalton, Brian E; Lu, Jessica; Leips, Jeff; Cronin, Thomas W; Carleton, Karen L

    2015-08-01

    Critical behaviours such as predation and mate choice often depend on vision. Visual systems are sensitive to the spectrum of light in their environment, which can vary extensively both within and among habitats. Evolutionary changes in spectral sensitivity contribute to divergence and speciation. Spectral sensitivity of the retina is primarily determined by visual pigments, which are opsin proteins bound to a chromophore. We recently discovered that photoreceptors in different regions of the retina, which view objects against distinct environmental backgrounds, coexpress different pairs of opsins in an African cichlid fish, Metriaclima zebra. This coexpression tunes the sensitivity of the retinal regions to the corresponding backgrounds and may aid in detection of dark objects, such as predators. Although intraretinal regionalization of spectral sensitivity in many animals correlates with their light environments, it is unknown whether variation in the light environment induces developmentally plastic alterations of intraretinal sensitivity regions. Here, we demonstrate with fluorescent in situ hybridization and qPCR that the spectrum and angle of environmental light both influence the development of spectral sensitivity regions by altering the distribution and level of opsins across the retina. Normally, M. zebra coexpresses LWS opsin with RH2Aα opsin in double cones of the ventral but not the dorsal retina. However, when illuminated from below throughout development, adult M. zebra coexpressed LWS and RH2Aα in double cones both dorsally and ventrally. Thus, environmental background spectra alter the spectral sensitivity pattern that develops across the retina, potentially influencing behaviours and related evolutionary processes such as courtship and speciation. PMID:26175094

  5. Assessment of the petroleum, coal, and geothermal resources of the economic community of West African states (ECOWAS) region

    SciTech Connect

    Mattick, R.E.

    1982-01-01

    Approximately 85 percent of the land area of the ECOWAS (Economic Community of West African States) region is covered by basement rocks (igneous and highly metamorphosed rocks) or relatively thin layers of Paleozoic, Upper Precambrian, and Continental Intercalaire sedimentary rocks. These areas have little or no petroleum potential. The ECOWAS region can be divided into 13 sedimentary basins on the basis of analysis of the geologic framework of Africa. These 13 basins can be further grouped into 8 categories on the basis of similarities in stratigraphy, geologic history, and probable hydrocarbon potential. The author has attempted to summarize the petroleum potential within the geologic framework of the region. The coal discoveries can be summarized as follows: the Carboniferous section in the Niger Basin; the Paleocene-Maestrichtian, Maestrichtian, and Eocene sections in the Niger Delta and Benin; the Maestrichtian section in the Senegal Basin; and the Pleistocene section in Sierra Leone. The only proved commercial deposits are the Paleocene-Maestrichtian and Maestrichtian subbituminous coal beds of the Niger Delta. Some of the lignite deposits of the Niger Delta and Senegal Basin, however, may be exploitable in the future. Published literature contains limited data on heat-flow values in the ECOWAS region. It is inferred, however, from the few values available and the regional geology that the development of geothermal resources, in general, would be uneconomical. Exceptions may include a geopressured zone in the Niger Delta and areas of recent tectonic activity in the Benue Trough and Cameroon. Development of the latter areas under present economic conditions is not feasible.

  6. The impact of the African Great Lakes on the regional climate in a dynamically downscaled CORDEX simulation (COSMO-CLM)

    NASA Astrophysics Data System (ADS)

    Thiery, W.; Panitz, H.; van Lipzig, N.

    2013-12-01

    Owing to the strong contrast in albedo, roughness and heat capacity between land and water, lakes significantly influence the exchange of moisture, heat and momentum between the surface and the boundary layer. To investigate this two-way interaction, a correct representation of lakes within regional climate models is essential. To this end, the one-dimensional lake parameterisation scheme FLake was recently coupled to the regional climate model COSMO-CLM (CCLM). One region where lakes constitute a key component of the climate system is the African Great Lakes region. In this study, the CCLM CORDEX-Africa evaluation simulation is dynamically downscaled from 0.44° (50 km) to 0.0625° (7 km) over East-Africa. The performance of two lake modules within CCLM are compared for the period 1999-2008: the default FLake scheme and the alternative Community Land Model. Model results are evaluated in a three-step procedure. First, the atmospheric state variables near-surface temperature, precipitation, surface energy fluxes, fractional cloud cover and column precipitable water are evaluated using in-situ based and satellite-derived products. Second, a comprehensive set of in-situ water temperature profile observations serves to evaluate the temporal evolution of water temperatures at three sites: Lake Kivu (Ishungu), Lake Tanganyika's northern basin (Kigoma) and southern basin (Mpulungu). Finally, spatial variability of surface temperatures in Lake Kivu and Lake Tanganyika are evaluated on the basis of satellite-derived lake surface temperatures. Subsequently, the preferred model configuration is used to quantify and understand effects by lakes reported for other regions in the world, such as a dampened diurnal temperature range, enhanced evaporation, modified surface layer stability, increased downwind precipitation, stronger winds, and the formation of local circulation patterns. This is achieved through comparison to a model integration excluding lake effects.

  7. Assessment of Uncertainties in the Response of the African Monsoon Precipitation to Land Use Change in Regional Model Simulations

    NASA Astrophysics Data System (ADS)

    Hagos, S. M.; Leung, L.; Xue, Y.; Boone, A. A.; Huang, M.; Yoon, J.

    2013-12-01

    Land use and land cover over Africa have changed substantially over the last sixty years and this change has been proposed to affect monsoon circulation and precipitation. This study examines the uncertainties on the effect of these changes on the African Monsoon system and Sahel precipitation using an ensemble of regional model simulations with different combinations of land surface and cumulus parameterization schemes. Although the magnitude of the response covers a broad range of values, most of the simulations show a decline in Sahel precipitation due to the expansion of pasture and croplands at the expense of trees and shrubs and an increase in surface air temperature. The relationship between the model responses to land use change and the climatologies of the control simulations is also examined. Simulations that are climatologically too dry or too wet compared to observations and reanalyses have weak response to land use change because they are in moisture or energy limited regimes respectively. The ones that lie in between and therefore land-atmosphere interactions play a more significant role have stronger response to the land use and land cover changes. Much of the change in precipitation is related to changes in circulation, particularly to the response of the intensity and latitudinal position of the African Easterly Jet, which varies with the changes in meridional surface temperature gradients. The study highlights the need for measurements of the surface fluxes across the meridional cross-section of the Sahel to evaluate models and thereby allowing human impacts such as land use change on the monsoon to be projected more realistically.

  8. Assessment of uncertainties in the response of the African monsoon precipitation to land use change simulated by a regional model

    NASA Astrophysics Data System (ADS)

    Hagos, Samson; Leung, L. Ruby; Xue, Yongkang; Boone, Aaron; de Sales, Fernando; Neupane, Naresh; Huang, Maoyi; Yoon, Jin-Ho

    2014-11-01

    Land use and land cover (LULC) over Africa have changed substantially over the last 60 years and this change has been proposed to affect monsoon circulation and precipitation. This study examines the uncertainties of model simulated response in the African monsoon system and Sahel precipitation due to LULC change using a set of regional model simulations with different combinations of land surface and cumulus parameterization schemes. Although the magnitude of the response covers a broad range of values, most of the simulations show a decline in Sahel precipitation due to the expansion of pasture and croplands at the expense of trees and shrubs and an increase in surface air temperature. The relationship between the model responses to LULC change and the climatologists of the control simulations is also examined. Simulations that are climatologically too dry or too wet compared to observations and reanalyses have weak response to land use change because they are in moisture or energy limited regimes respectively. The ones that lie in between have stronger response to the LULC changes, showing a more significant role in land-atmosphere interactions. Much of the change in precipitation is related to changes in circulation, particularly to the response of the intensity and latitudinal position of the African Easterly Jet, which varies with the changes in meridional surface temperature gradients. The study highlights the need for measurements of the surface fluxes across the meridional cross-section of the Sahel to evaluate models and thereby allowing human impacts such as land use change on the monsoon to be projected more realistically.

  9. Comparative phylogeography of African rain forest trees: A review of genetic signatures of vegetation history in the Guineo-Congolian region

    NASA Astrophysics Data System (ADS)

    Hardy, Olivier J.; Born, Céline; Budde, Katarina; Daïnou, Kasso; Dauby, Gilles; Duminil, Jérôme; Ewédjé, Eben-Ezer B. K.; Gomez, Céline; Heuertz, Myriam; Koffi, Guillaume K.; Lowe, Andrew J.; Micheneau, Claire; Ndiade-Bourobou, Dyana; Piñeiro, Rosalía; Poncet, Valérie

    2013-07-01

    The biogeographic history of the African rain forests has been contentious. Phylogeography, the study of the geographic distribution of genetic lineages within species, can highlight the signatures of historical events affecting the demography and distribution of species (i.e. population fragmentation or size changes, range expansion/contraction) and, thereby, the ecosystems they belong to. The accumulation of recent data for African rain forests now enables a first biogeographic synthesis for the region. In this review, we explain which phylogeographic patterns are expected under different scenarios of past demographic change, and we give an overview of the patterns detected in African rain forest trees to discuss whether they support alternative hypotheses regarding the history of the African rain forest cover. The major genetic discontinuities in the region support the role of refugia during climatic oscillations, though not necessarily following the classically proposed scenarios. We identify in particular a genetic split between the North and the South of the Lower Guinean region. Finally we provide some perspectives for future study.

  10. Simulation of the West African monsoon onset using the HadGEM3-RA regional climate model

    NASA Astrophysics Data System (ADS)

    Diallo, Ismaïla; Bain, Caroline L.; Gaye, Amadou T.; Moufouma-Okia, Wilfran; Niang, Coumba; Dieng, Mame D. B.; Graham, Richard

    2014-08-01

    The performance of the Hadley Centre Global Environmental Model version 3 regional climate model (HadGEM3-RA) in simulating the West African monsoon (WAM) is investigated. We focus on performance for monsoon onset timing and for rainfall totals over the June-July-August (JJA) season and on the model's representation of the underlying dynamical processes. Experiments are driven by the ERA-Interim reanalysis and follow the CORDEX experimental protocol. Simulations with the HadGEM3 global model, which shares a common physical formulation with HadGEM3-RA, are used to gain insight into the causes of HadGEM3-RA simulation errors. It is found that HadGEM3-RA simulations of monsoon onset timing are realistic, with an error in mean onset date of two pentads. However, the model has a dry bias over the Sahel during JJA of 15-20 %. Analysis suggests that this is related to errors in the positioning of the Saharan heat low, which is too far south in HadGEM3-RA and associated with an insufficient northward reach of the south-westerly low-level monsoon flow and weaker moisture convergence over the Sahel. Despite these biases HadGEM3-RA's representation of the general rainfall distribution during the WAM appears superior to that of ERA-Interim when using Global Precipitation Climatology Project or Tropical Rain Measurement Mission data as reference. This suggests that the associated dynamical features seen in HadGEM3-RA can complement the physical picture available from ERA-Interim. This approach is supported by the fact that the global HadGEM3 model generates realistic simulations of the WAM without the benefit of pseudo-observational forcing at the lateral boundaries; suggesting that the physical formulation shared with HadGEM3-RA, is able to represent the driving processes. HadGEM3-RA simulations confirm previous findings that the main rainfall peak near 10°N during June-August is maintained by a region of mid-tropospheric ascent located, latitudinally, between the cores of

  11. mtDNA control-region sequence variation suggests multiple independent origins of an "Asian-specific" 9-bp deletion in sub-Saharan Africans.

    PubMed Central

    Soodyall, H.; Vigilant, L.; Hill, A. V.; Stoneking, M.; Jenkins, T.

    1996-01-01

    The intergenic COII/tRNA(Lys) 9-bp deletion in human mtDNA, which is found at varying frequencies in Asia, Southeast Asia, Polynesia, and the New World, was also found in 81 of 919 sub-Saharan Africans. Using mtDNA control-region sequence data from a subset of 41 individuals with the deletion, we identified 22 unique mtDNA types associated with the deletion in Africa. A comparison of the unique mtDNA types from sub-Saharan Africans and Asians with the 9-bp deletion revealed that sub-Saharan Africans and Asians have sequence profiles that differ in the locations and frequencies of variant sites. Both phylogenetic and mismatch-distribution analysis suggest that 9-bp deletion arose independently in sub-Saharan Africa and Asia and that the deletion has arisen more than once in Africa. Within Africa, the deletion was not found among Khoisan peoples and was rare to absent in western and southwestern African populations, but it did occur in Pygmy and Negroid populations from central Africa and in Malawi and southern African Bantu-speakers. The distribution of the 9-bp deletion in Africa suggests that the deletion could have arisen in central Africa and was then introduced to southern Africa via the recent "Bantu expansion." PMID:8644719

  12. The Impact of the Atlantic Cold Tongue on West African Monsoon Onset in Regional Model Simulations for 1998-2002

    NASA Technical Reports Server (NTRS)

    Druyan, Leonard M.; Fulakeza, Matthew B.

    2014-01-01

    The Atlantic cold tongue (ACT) develops during spring and early summer near the Equator in the Eastern Atlantic Ocean and Gulf of Guinea. The hypothesis that the ACT accelerates the timing of West African monsoon (WAM) onset is tested by comparing two regional climate model (RM3) simulation ensembles. Observed sea surface temperatures (SST) that include the ACT are used to force a control ensemble. An idealized, warm SST perturbation is designed to represent lower boundary forcing without the ACT for the experiment ensemble. Summer simulations forced by observed SST and reanalysis boundary conditions for each of five consecutive years are compared to five parallel runs forced by SST with the warm perturbation. The article summarizes the sequence of events leading to the onset of the WAM in the Sahel region. The representation of WAM onset in RM3 simulations is examined and compared to Tropical Rainfall Measuring Mission (TRMM), Global Precipitation Climatology Project (GPCP) and reanalysis data. The study evaluates the sensitivity of WAM onset indicators to the presence of the ACT by analysing the differences between the two simulation ensembles. Results show that the timing of major rainfall events and therefore theWAM onset in the Sahel are not sensitive to the presence of the ACT. However, the warm SST perturbation does increase downstream rainfall rates over West Africa as a consequence of enhanced specific humidity and enhanced northward moisture flux in the lower troposphere.

  13. Source regions of whistlers detected in the American, African/European and Western Pacific sectors

    NASA Astrophysics Data System (ADS)

    Koronczay, David; Steinbach, Peter; Lichtenberger, Janos

    2016-04-01

    AWDANet is a recently completed network for automatic whistler detection and analysis. Here we investigate whistler measurements from its first years of operation, analyzing the time distribution of whistlers detected at various stations in Western Antarctica, Southern Africa, Europe and the Western Pacific region. Whistlers detected on the ground are thought to originate in their magnetic conjugate location, travelling through the plasmasphere before returning to the ground. We carry out a correlation analysis, comparing the occurrence of whistler events to lightning strokes using multiple lightning databases, including WWLLN (World Wide Lightning Location Network), to locate the events' source region. Our results can lead to a better understanding of the source regions and mechanisms of whistlers observed on the ground. This knowledge can improve their use as a tool to probe the plasmasphere.

  14. A Regional Stable Carbon Isotope Dendro-Climatology from the South African Summer Rainfall Area

    PubMed Central

    2016-01-01

    Carbon isotope analysis of four baobab (Adansonia digitata L.) trees from the Pafuri region of South Africa yielded a 1000-year proxy rainfall record. The Pafuri record age model was based on 17 radiocarbon dates, cross correlation of the climate record, and ring structures that were presumed to be annual for two of the trees. Here we present the analysis of five additional baobabs from the Mapungubwe region, approximately 200km west of Pafuri. The Mapungubwe chronology demonstrates that ring structures are not necessarily annually formed, and accordingly the Pafuri chronology is revised. Changes in intrinsic water-use efficiency indicate an active response by the trees to elevated atmospheric CO2, but this has little effect on the environmental signal. The revised Pafuri record, and the new Mapungubwe record correlate significantly with local rainfall. Both records confirm that the Medieval Warm Period was substantially wetter than present, and the Little Ice Age was the driest period in the last 1000 years. Although Mapungubwe is generally drier than Pafuri, both regions experience elevated rainfall peaking between AD 1570 and AD 1620 after which dry conditions persist in the Mapungubwe area until about AD 1840. Differences between the two records correlate with Agulhas Current sea-surface temperature variations suggesting east/west displacement of the temperate tropical trough system as an underlying mechanism. The Pafuri and Mapungubwe records are combined to provide a regional climate proxy record for the northern summer rainfall area of southern Africa. PMID:27427912

  15. A Regional Stable Carbon Isotope Dendro-Climatology from the South African Summer Rainfall Area.

    PubMed

    Woodborne, Stephan; Gandiwa, Patience; Hall, Grant; Patrut, Adrian; Finch, Jemma

    2016-01-01

    Carbon isotope analysis of four baobab (Adansonia digitata L.) trees from the Pafuri region of South Africa yielded a 1000-year proxy rainfall record. The Pafuri record age model was based on 17 radiocarbon dates, cross correlation of the climate record, and ring structures that were presumed to be annual for two of the trees. Here we present the analysis of five additional baobabs from the Mapungubwe region, approximately 200km west of Pafuri. The Mapungubwe chronology demonstrates that ring structures are not necessarily annually formed, and accordingly the Pafuri chronology is revised. Changes in intrinsic water-use efficiency indicate an active response by the trees to elevated atmospheric CO2, but this has little effect on the environmental signal. The revised Pafuri record, and the new Mapungubwe record correlate significantly with local rainfall. Both records confirm that the Medieval Warm Period was substantially wetter than present, and the Little Ice Age was the driest period in the last 1000 years. Although Mapungubwe is generally drier than Pafuri, both regions experience elevated rainfall peaking between AD 1570 and AD 1620 after which dry conditions persist in the Mapungubwe area until about AD 1840. Differences between the two records correlate with Agulhas Current sea-surface temperature variations suggesting east/west displacement of the temperate tropical trough system as an underlying mechanism. The Pafuri and Mapungubwe records are combined to provide a regional climate proxy record for the northern summer rainfall area of southern Africa. PMID:27427912

  16. Formation and maintenance of nocturnal low-level stratus over the southern West African monsoon region during AMMA 2006

    NASA Astrophysics Data System (ADS)

    Schuster, Robert; Fink, Andreas; Knippertz, Peter

    2013-04-01

    The southern parts of West Africa, from the coast to about 9°N, are frequently covered by an extensive deck of shallow, low (200 - 400 m above ground) stratus or stratocumulus clouds during the summer monsoon season as shown by recent studies based on ground observations and new satellite products. These clouds usually form at night in association with a nocturnal low-level jet (NLLJ) and can persist into the early afternoon hours until they are dissipated or replaced by fair-weather cumuli. Recent work suggests that the stratus deck and its effect on the surface radiation balance are unsatisfactorily represented in standard satellite retrievals and simulations by state-of-the-art climate models. Here we use high-resolution regional simulations with the Weather Research and Forecast (WRF) model and observations from the African Monsoon Multidisciplinary Analysis (AMMA) 2006 campaign to investigate (a) the spatiotemporal distribution, (b) the influence on the radiation balance, and (c) the detailed formation and maintenance mechanisms of the stratiform clouds. The model configuration used for this study has been determined following an extensive sensitivity study. The main conclusions are: (a) At least some configurations of WRF satisfactorily reproduce the diurnal cycle of the low cloud evolution. (b) The simulated stratus deck forms after sunset along the coast, spreads inland in the course of the night, and dissipates in the early afternoon. (c) The average surface net radiation balance in stratus-dominated regions is 35 W m-2 lower than in those with less clouds. (d) The cloud formation is related to a subtle balance between "stratogenic" upward (downward) fluxes of latent (sensible) heat caused by shear-driven turbulence below the NLLJ, cold advection from the ocean, forced lifting at the windward side of orography, and radiative cooling on one hand, and "stratolytic" dry advection and latent heating on the other hand. Future work should focus on the influence

  17. Integrating Oral Health with Non-Communicable Diseases as an Essential Component of General Health: WHO's Strategic Orientation for the African Region.

    PubMed

    Varenne, Benoit

    2015-05-01

    In the context of the emerging recognition of non-communicable diseases (NCDs), it has never been more timely to explore the World Health Organization (WHO) strategic orientations on oral health in the WHO African region and to raise awareness of a turning point in the search for better oral health for everyone. The global initiative against NCDs provides a unique opportunity for the oral health community to develop innovative policies for better recognition of oral health, as well as to directly contribute to the fight against NCDs and their risk factors. The WHO African region has led the way in developing the first regional oral health strategy for the prevention and control of oral diseases integrated with NCDs. The support of the international oral health community in this endeavor is urgently needed for making a success story of this initiative of integrating oral health into NCDs. PMID:25941239

  18. The impact of the African Great Lakes on the regional climate in a dynamically downscaled CORDEX simulation

    NASA Astrophysics Data System (ADS)

    Thiery, Wim; Panitz, Hans-Jürgen; Davin, Edouard; van Lipzig, Nicole

    2014-05-01

    Owing to the strong contrast in albedo, roughness and heat capacity between land and water, lakes significantly influence the exchange of moisture, heat and momentum between the surface and the boundary layer. To investigate this two-way interaction, a correct representation of lakes within regional climate models is essential. To this end, the one-dimensional lake parameterisation scheme FLake was recently coupled to the regional climate model COSMO-CLM (CCLM). One region where lakes constitute a key component of the climate system is the African Great Lakes region. In this study, the CCLM CORDEX-Africa evaluation simulation is dynamically downscaled from 0.44° (50 km) to 0.0625° (7 km) over East-Africa, an unprecedented resolution for this region. The performance of different CCLM configurations are compared for the period 1999-2008: in particular, CCLM is tested for its sensitivity to the choice of the lake surface temperature description (SST, FLake, an improved version of FLake and Hostetler) and the land surface model (Terra and Community Land Model). Model results are evaluated in a three-step procedure. First, the atmospheric state variables near-surface temperature, precipitation, surface energy fluxes, fractional cloud cover and column precipitable water are evaluated using in-situ based and satellite-derived products. Second, a comprehensive set of in-situ water temperature profile observations serves to evaluate the temporal evolution of water temperatures at three sites: Lake Kivu (Ishungu), Lake Tanganyika's northern basin (Kigoma) and southern basin (Mpulungu). Finally, spatial variability of surface temperatures in Lake Kivu and Lake Tanganyika are evaluated on the basis of satellite-derived lake surface temperatures. Subsequently, the preferred model configuration is used to quantify and understand effects by lakes reported for other regions in the world, such as a dampened diurnal temperature range, enhanced evaporation, modified surface layer

  19. Regional differences in seasonal timing of rainfall discriminate between genetically distinct East African giraffe taxa.

    PubMed

    Thomassen, Henri A; Freedman, Adam H; Brown, David M; Buermann, Wolfgang; Jacobs, David K

    2013-01-01

    Masai (Giraffa tippelskirchi), Reticulated (G. reticulata) and Rothschild's (G. camelopardalis) giraffe lineages in East Africa are morphologically and genetically distinct, yet in Kenya their ranges abut. This raises the question of how divergence is maintained among populations of a large mammal capable of long-distance travel, and which readily hybridize in zoos. Here we test four hypotheses concerning the maintenance of the phylogeographic boundaries among the three taxa: 1) isolation-by-distance; 2) physical barriers to dispersal; 3) general habitat differences resulting in habitat segregation; or 4) regional differences in the seasonal timing of rainfall, and resultant timing of browse availability. We used satellite remotely sensed and climate data to characterize the environment at the locations of genotyped giraffes. Canonical variate analysis, random forest algorithms, and generalized dissimilarity modelling were employed in a landscape genetics framework to identify the predictor variables that best explained giraffes' genetic divergence. We found that regional differences in the timing of precipitation, and resulting green-up associated with the abundance of browse, effectively discriminate between taxa. Local habitat conditions, topographic and human-induced barriers, and geographic distance did not aid in discriminating among lineages. Our results suggest that selection associated with regional timing of events in the annual climatic cycle may help maintain genetic and phenotypic divergence in giraffes. We discuss potential mechanisms of maintaining divergence, and suggest that synchronization of reproduction with seasonal rainfall cycles that are geographically distinct may contribute to reproductive isolation. Coordination of weaning with green-up cycles could minimize the costs of lactation and predation on the young. Our findings are consistent with theory and empirical results demonstrating the efficacy of seasonal or phenologically dictated

  20. Regional Differences in Seasonal Timing of Rainfall Discriminate between Genetically Distinct East African Giraffe Taxa

    PubMed Central

    Thomassen, Henri A.; Freedman, Adam H.; Brown, David M.; Buermann, Wolfgang; Jacobs, David K.

    2013-01-01

    Masai (Giraffa tippelskirchi), Reticulated (G. reticulata) and Rothschild's (G. camelopardalis) giraffe lineages in East Africa are morphologically and genetically distinct, yet in Kenya their ranges abut. This raises the question of how divergence is maintained among populations of a large mammal capable of long-distance travel, and which readily hybridize in zoos. Here we test four hypotheses concerning the maintenance of the phylogeographic boundaries among the three taxa: 1) isolation-by-distance; 2) physical barriers to dispersal; 3) general habitat differences resulting in habitat segregation; or 4) regional differences in the seasonal timing of rainfall, and resultant timing of browse availability. We used satellite remotely sensed and climate data to characterize the environment at the locations of genotyped giraffes. Canonical variate analysis, random forest algorithms, and generalized dissimilarity modelling were employed in a landscape genetics framework to identify the predictor variables that best explained giraffes' genetic divergence. We found that regional differences in the timing of precipitation, and resulting green-up associated with the abundance of browse, effectively discriminate between taxa. Local habitat conditions, topographic and human-induced barriers, and geographic distance did not aid in discriminating among lineages. Our results suggest that selection associated with regional timing of events in the annual climatic cycle may help maintain genetic and phenotypic divergence in giraffes. We discuss potential mechanisms of maintaining divergence, and suggest that synchronization of reproduction with seasonal rainfall cycles that are geographically distinct may contribute to reproductive isolation. Coordination of weaning with green-up cycles could minimize the costs of lactation and predation on the young. Our findings are consistent with theory and empirical results demonstrating the efficacy of seasonal or phenologically dictated

  1. Crystal forms and surface textures of alluvial diamonds from the Western Region of the Central African Republic

    NASA Astrophysics Data System (ADS)

    Censier, C.; Tourenq, J.

    1995-06-01

    The most common crystal forms of the diamonds from the alluvial deposits in the Western Region of the Central African Republic were examined by scanning electron microscope (SEM) in an attempt to determine their geological history. The marks observed are related to two distinct periods in the geological history of the diamonds: the magmatic episode and their hydraulic transport. The effects of significant magmatic corrosion undergone by the diamonds during their ascent from the upper mantle are shown by the predominance of rhombododecahedral forms over octahedral forms and the frequent occurrence on the crystal faces of pyramidal depressions with triangular (111) or square (100) bases, as well as of V-shaped figures (111) or stepped figures (on the faces around the ternary axes). Some impact marks probably occurred during the explosive episode of kimberlite extrusion. Other impact marks, the marks of general wear, and the high proportion of gemstone-quality diamonds indicate the lengthy transport. They thus also indicate that the diamonds have undergone a prolonged geological history after the erosion of the kimberlite. This suggests that the kimberlite are separated from the Carnot Sandstone Formation by a considerable distance. The diamonds were stored in Albian-Maastrichtian rocks before they become concentrated in the Recent alluvium.

  2. Characterisation of GPS-TEC in the African equatorial and low latitude region and the regional evaluation of the IRI model

    NASA Astrophysics Data System (ADS)

    Adebiyi, S. J.; Adimula, I. A.; Oladipo, O. A.

    2016-06-01

    With the increasing application of Global Navigation Satellite System (GNSS) products and services, knowledge of the Total Electron Content (TEC) variation is vital, particularly in historically under-sampled regions. The ionospheric induced-error, which is the largest and most variable error source of GNSS applications, is proportional to TEC along the satellite-receiver path. Simultaneous Global Positioning System (GPS) measurements from six African equatorial and low latitude stations in the southern hemisphere are used to investigate the latitudinal variation of TEC over the region during the year 2013, a year of moderate solar activity. The analysis reveals some detailed features of seasonal, month-to-month and solar activity dependence of TEC. The seasonal variation of TEC revealed that the daytime and the pre-midnight values of TEC for stations located close to the geographic equator is considerably higher in equinoxes and June solstice compared to stations farther from the equator, however, the difference is insignificant during the December solstice. The month-to-month variation of TEC shows semi-annual symmetry/asymmetry in TEC values for stations closer/farther from the equator. TEC sensitivity to solar activity shows significant seasonal and latitudinal characteristics. Generally, a relatively good correlation exists between TEC and F10.7 for stations around the Equatorial Ionization Anomaly (EIA) region compared to those found at stations close to the equator. Beyond the EIA region, the correlation coefficients drop in all seasons. TEC predicted by the three topside options of the International Reference Ionosphere (IRI) 2012 model [i.e. the NeQuick (NeQ), IRI-2001 Corrected (IRI-01 Corr) and the IRI-2001 (IRI-01) options] exhibits latitudinal and seasonal characteristics. The NeQ option performed better than the other two options at stations located within the equatorial region in most of the months and seasons. Outside the EIA region, the IRI-01 Corr

  3. Assessing the Effects of Burned Areas on the Northern and Southern African Seasonal Climates: a Regional Modeling Study

    NASA Astrophysics Data System (ADS)

    De Sales, F.; Okin, G. S.; Xue, Y.; Dintwe, K.

    2015-12-01

    The occurrence of wildfires, whether natural or anthropogenic, is an important disturbance of the terrestrial ecosystems as it plays an essential role in shaping global and regional vegetation. This study presents an investigation of the impact of burned areas on the surface energy balance and precipitation in northern and southern Africa as simulated by a state-of-the-art regional modeling system. Mean burned area fraction derived from MODIS date-of-burning product was implemented in a set of WRF/SSiB2 simulations. Vegetation cover and LAI were degraded based on mean burned area fraction and survival rate for each vegetation land cover type. Additionally, ground darkening associated with ash and charcoal deposition was imposed by temporarily lowering the ground albedo after burning. Wildfire-induced vegetation and ground degradation increased the surface albedo by exposing the brighter bare ground of the region, which in turn caused a decrease in surface net radiation and evapotranspiration. Overall, post-fire land condition resulted in a decrease in precipitation over sub-Saharan Africa, associated with the weakening of the West African monsoon progression through the region. A decrease in atmospheric moisture flux convergence was observed in the burned areas, which played a dominant role in reducing precipitation. The areas with the largest precipitation impact were those covered by savannas and rainforests, where annual precipitation decreased by 3.8% and 3.3%, respectively. The resulting precipitation decrease and vegetation deterioration caused a drop in gross primary productivity in the region, which was strongest in late winter and early spring. This study suggests that the cooling and drying of atmosphere induced by the burned areas led to strengthening of subsidence during pre-onset and weakening of upward motion during onset and mature stages of the monsoon leading to a waning of convective instability and precipitation. Vertical air movement over the

  4. Assessment of the petroleum, coal, and geothermal resources of the Economic Community of West African States (ECOWAS) region

    USGS Publications Warehouse

    Mattick, R. E., (compiler)

    1982-01-01

    Approximately 85 percent of the land area of the ECOWAS (Economic Community of West African States) region is covered by basement rocks (igneous and highly metamorphosed rocks) or relatively thin layers of Paleozoic, Upper Precambrian, and 'Continental Intercalaire? sedimentary rocks. These areas have little or no petroleum potential. Areas of the ECOWAS region that have potential for petroleum production or potential for increased petroleum production include the narrow belt of sedimentary rocks that stretches along the continental margin from Mauritania to Nigeria and the Niger Delta and the Benue depression. The Senegal Basin, located on the continental margin of Mauritania, Senegal, Gambia, Guinea Bissau, and Guinea, has been intensely explored by the oil industry and most of the larger structures onshore and on the shelf probably have been tested by drilling with little or no resulting commercial production. Unless basic ideas pertaining to the petroleum geology of the Senegal Basin are revised, future discoveries are expected to be limited to small fields overlooked by industry at a time when petroleum prices were low. On the continental shelf of Sierra Leone and the continental shelf of northeast and central Liberia, the sedimentary rocks are relatively thin, and industry has shown little interest in the area. On the continental rise of these countries, however, the sedimentary section, deposited in a complex fault-block system, increases in thickness. A renewal of industry interest in this deep-water area will probably follow further development of deep-water production technology. A recent oil discovery on the continental slope off the Ivory Coast is expected to spur further exploration offshore of southeastern Liberia, Ivory Coast, Ghana, Togo, and Benin. This relatively unexplored area in the Gulf of Guinea has good possibilities .for the discovery of giant oil fields. Nigeria's oil development from the Niger Delta may have peaked, as 13 of 14 giant oil

  5. Mapping the earth conductivity-depth structure of African geomagnetic equatorial anomaly regions using solar quiet current variations

    NASA Astrophysics Data System (ADS)

    Ugbor, D. O.; Okeke, F. N.; Yumoto, K.

    2016-04-01

    The solar quiet day ionospheric (Sq) current variations observed in Abuja, Bangui and Addis Ababa were used to delineate the mantle conductivity-depth structure along the equatorial African regions. Spherical harmonic analysis (SHA) was employed in separating the internal and external field contributions to the Sq variations. For each of the paired external and internal coefficients of the SHA, we used transfer function to compute the conductivity-depth profile for the region. Strikingly, we observed increased electrical conductivity values in the Earth layers and deep depth penetration. The calculated average electrical conductivity values in Addis Ababa and Abuja are 0.087 Sm-1 and 0.104 Sm-1 at depths of 93 km and 121 km respectively. These values suddenly rose to 0.235 Sm-1 and 0.222 Sm-1 at depths of 440 km and 427 km respectively. In Bangui, the calculated average values are 0.092 Sm-1, 0.144 Sm-1, 0.312 Sm-1 and 0.466 Sm-1 at 96 km, 300 km, 834 km and 1228 km depths respectively. At the greatest depths of penetration of 1412 km, 1385 km and 1278 km in Addis Ababa, Abuja and Bangui, the electrical conductivity attained the highest values of 0.415 Sm-1, 0.467 Sm-1 and 0.515 Sm-1 respectively. Two most Earth conductive layers were discovered in the magnetic equatorial zone. These layers lie between the depth of about 100 and 400 km within the upper mantle and beyond 1200 km in the lower mantle. It can be inferred that the closer one goes towards the Earth magnetic equator; the deeper the Sq current can penetrate the Earth's interior.

  6. Derivation of detrital rutile in the Yaoundé region from the Neoproterozoic Pan-African belt in southern Cameroon (Central Africa)

    NASA Astrophysics Data System (ADS)

    Stendal, Henrik; Toteu, Sadrack Félix; Frei, Robert; Penaye, Joseph; Njel, Urbain Olivier; Bassahak, Jean; Nni, Jean; Kankeu, Boniface; Ngako, Vincent; Hell, Joseph Victor

    2006-04-01

    Rutile, as an important component in alluvial or eluvial heavy mineral deposits, is known in southern Cameroon. These deposits are underlain by the Neoproterozoic low- to high-grade Yaoundé Group. Geochemical, thermometric, fluid inclusion and Pb isotopic studies of the rutile from alluvial and eluvial concentrates and from medium-grade micaschist from the nearby Yaoundé region permit the following conclusions: (1) alluvial and eluvial rutile of the Yaoundé region are derived from the degradation of metapelites, metamafic rocks and pegmatites of the nearby Yaoundé Group; (2) rutile in the Yaoundé Group formed during the Pan-African metamorphism, or was inherited as detrital rutile from a ˜900 Ma source. The study also shows that the rutile can be used to trace the history of the Pan-African belt north of the Congo craton.

  7. Future water availability in North African dams simulated by high-resolution regional climate models

    NASA Astrophysics Data System (ADS)

    Tramblay, Yves; Jarlan, Lionel; Hanich, Lahoucine; Somot, Samuel

    2016-04-01

    In North Africa, the countries of Morocco, Algeria and Tunisia are already experiencing water scarcity and a strong interannual variability of precipitation. To better manage their existing water resources, several dams and reservoirs have been built on most large river catchments. The objective of this study is to provide quantitative scenarios of future changes in water availability for the 47 major dams and reservoirs catchments located in North Africa. An ensemble of regional climate models (RCM) with a spatial resolution of 12km, driven by different general circulation models (GCM), from the EuroCORDEX experiment have been considered to analyze the projected changes on temperature, precipitation and potential evapotranspiration (PET) for two scenarios (RCP4.5 and RCP8.5) and two time horizons (2040-2065 and 2065-2090). PET is estimated from RCM outputs either with the FAO-Penman-Monteith (PM) equation, requiring air temperature, relative humidity, net radiation and wind, or with the Hargreave Samani (HS) equation, requiring only air temperature. The water balance is analyzed by comparing the climatic demand and supply of water, considering that for most of these catchments groundwater storage is negligible over long time periods. Results indicated a future temperature increase for all catchments between +1.8° and +4.2°, depending on the emission scenario and the time period considered. Precipitation is projected to decrease between -14% to -27%, mainly in winter and spring, with a strong East to West gradient. PET computed from PM or HS formulas provided very similar estimates and projections, ranging between +7% to +18%. Changes in PET are mostly driven by rising temperatures and are greatest during dry summer months than for the wet winter season. Therefore the increased PET has a lower impact than declining precipitation on future water availability, which is expected to decrease by -19% to -33% on average.

  8. The African superswell

    NASA Technical Reports Server (NTRS)

    Nyblade, Andrew A.; Robinson, Scott W.

    1994-01-01

    Maps of residual bathymetry in the ocean basins around the African continent reveal a broad bathymetric swell in the southeastern Atlantic Ocean with an amplitude of about 500 m. We propose that this region of anomalously shallow bathymetry, together with the contiguous eastern and southern African plateaus, form a superswell which we refer to as the African superswell. The origin of the African superswell is uncertain. However, rifting and volcanism in eastern Africa, as well as heat flow measurements in southern Africa and the southeastern Atlantic Ocean, suggest that the superswell may be attributed, at least in part, to heating of the lithosphere.

  9. Seismic structure of the crust and lithospheric mantle of the southern African cratonic region

    NASA Astrophysics Data System (ADS)

    Youssof, M.; Thybo, H.; Artemieva, I. M.; Levander, A.

    2013-12-01

    We present a new seismic model for the structure of the crust and lithospheric mantle in southern Africa constrained by a joint study of seismic receiver functions and finite-frequency tomography, using the high-quality data from the South Africa Seismic Experiment (SASE). A) The crust has a highly heterogeneous structure with short wavelength variations in (i) thickness, (ii) composition (reflected in Vp/Vs-ratio calculated for all SASE stations), and (iii) Moho sharpness (which is quantified and mapped for the entire region) (Youssof et al., Tectonophysics, in review). By mapping these three parameters, we distinguish ~20 crustal blocks that do not everywhere coincide with surface tectonic features. Our RFs also demonstrate strong azimuthal anisotropy in the crust, with a typical crustal contribution to the total S-wave splitting of at least 30%. Spatial correlation of the S-wave polarization directions of crustal and mantle anisotropy indicates (i) the presence of three distinct Archean lithospheric terranes and (ii) coupling between the crust and lithospheric mantle in most of the study area, with a strong decoupling in western Kaapvaal where the crustal anisotropy is strongest. The similarity of anisotropy directions in the crust and mantle beneath much of the Kaapvaal craton indicates that (a) the seismic anisotropy originates at the time of cratonization and (b) the observed correspondence between the present direction of absolute plate motion (APM) and lithosphere anisotropy is coincidental. B) A new 3D high-resolution seismic model of the lithospheric mantle has been determined from finite frequency tomographic inversions of teleseismic P- and S- body wave data. The two velocity models are very similar in structure, but differ in the relative P- and S-wave velocity anomalies. We find that: 1) the fast lithospheric keels extends very deep, perhaps to depths of 300-350 km and 250 km beneath the Kaapvaal and Zimbabwe cratons, respectively, and 2) the Archean

  10. Regional diversity patterns in African bovids, hyaenids, and felids during the past 3 million years: the role of taphonomic bias and implications for the evolution of Paranthropus

    NASA Astrophysics Data System (ADS)

    Patterson, David B.; Faith, J. Tyler; Bobe, René; Wood, Bernard

    2014-07-01

    Reconstructing patterns of Plio-Pleistocene mammalian faunal exchange between eastern and southern Africa may help us to better understand patterns of evolution within the hominin clade. However, differences in geological context, taphonomic history and collection methods, as well as a lack of a precise chronology in one of the regions, complicate attempts to compare the faunas of the two regions, but access to new comprehensive datasets encouraged us to re-examine this critical time period in the African paleontological record. In this study, we examine the biogeographic histories of three terrestrial African mammalian families whose fossil records span the past 3 million years to test hypotheses related to the evolutionary history of the hominin genus Paranthropus. We used presence/absence data for 117 species from 38 genera within the family Bovidae and 34 species from 15 genera within the families Hyaenidae and Felidae from 52 eastern African and 40 southern African fossil localities. These assemblages were placed into 500 ka time slices and compared at both the genus and species level using the Jaccard index of faunal similarity. Our findings indicate that sampling biases have more effect on the patterns of interchange between eastern and southern African Bovidae than they do the patterns of interchange seen in the Hyaenidae and Felidae. However, even when these biases are taken into account there are persistent differences in the degree of interchange within and between these families. These findings suggest that mammalian groups (including hominins) can have very different histories of exchange between eastern and southern Africa over the past 3 million years. There is no a priori reason why any of the three families we examined is a suitable proxy for the eastern and southern African hyper-megadont and megadont hominin taxa presently included in Paranthropus, but of the three we suggest that the Bovidae is likely to come closest to being an appropriate

  11. Response of Seasonal Atlantic Tropical Cyclone Activity to Suppression of African Easterly Waves in a Regional Climate Model

    NASA Astrophysics Data System (ADS)

    Patricola, C. M.; Saravanan, R.; Chang, P.

    2014-12-01

    Atlantic tropical cyclones and African easterly waves (AEWs) are strongly linked on the synoptic timescale, with about 85% of observed major Atlantic hurricanes originating from AEWs (e.g., Landsea et al. 1993). However, the influence of variability in AEWs on seasonal Atlantic tropical cyclone activity is not fully understood; a positive correlation between AEW activity and Atlantic tropical cyclone activity exists on the interannual timescale during just some periods of the observational record (e.g., Thorncroft and Hodges, 2001; Hopsch et al. 2007). This study investigates the impact of AEWs on seasonal Atlantic tropical cyclone activity using regional climate model simulations in which AEWs were either prescribed or removed through the lateral boundary condition (LBC). The control simulation (10-member ensemble) was run at 27 km resolution and used 6-hourly LBCs from the NCEP CFS Reanalysis and daily NOAA Optimum Interpolation (OI) V2 sea surface temperature (SST) from the year 2005. In the experiment AEWs were suppressed by filtering 2-10 day variability over tropical latitudes from the eastern LBC, located along the west coast of the Sahel. The difference in Atlantic tropical cyclone frequency was insignificant between the simulations in which AEWs were prescribed versus suppressed, indicating that AEWs are not necessary to maintain climatological tropical cyclone frequency even though tropical cyclones readily originate from these features. This further implies that seasonal Atlantic tropical cyclone frequency is uninfluenced by variability in AEWs, and that the value of AEW variability as a predictor of Atlantic tropical cyclones is limited to the weekly timescale. However in response to filtering AEWs, accumulated cyclone energy significantly increased by about 15% of the control simulation mean and the spatial pattern of track density shifted in association with changes in steering winds. This suggests the importance of AEWs in impacting tropical cyclone

  12. 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.

  13. Holocene sea surface temperatures in the East African Coastal Current region and their relationship with North Atlantic climate

    NASA Astrophysics Data System (ADS)

    Kuhnert, Henning; Kuhlmann, Holger; Mohtadi, Mahyar; Pätzold, Jürgen

    2013-04-01

    The East African Coastal Current (EACC) is one of the western boundary currents of the Indian Ocean and represents the only pathway for southern water masses to enter the Arabian Sea. Today, sea surface temperatures (SST) in the western boundary currents region covary with those in large parts of the central tropical Indian Ocean. The latter play an important role in global climate by influencing the mean state of the North Atlantic Oscillation (NAO) and associated Atlantic SST anomalies (Hoerling et al., 2001). In the EACC region paleoclimate data are sparse and its Holocene temperature history is unexplored. We present data from a 5 m long sediment core retrieved off northern Tanzania where the EACC flows northward year-round. Proximity to the Pangani River mouth provides a steady sediment supply. We have reconstructed SST from Mg/Ca and stable oxygen isotope ratios (^18O) of the surface-dwelling planktonic foraminifera species Globigerinoides ruber (sensu stricto). Our record spans the time period from 9700 to 1400 years BP at an average temporal resolution of 40 years. The Holocene is characterized by a sequence of intervals representing cool, warm, cool, and intermediate SST, with boundaries at 7.8, 5.6, and 4.4 ka BP. SST anomalies relative to the series mean range from -0.6 to +0.75 ° C. This pattern strikingly resembles a Northwest Atlantic foraminiferal ^18O record (Cléroux et al., 2012), with warm Indian SST corresponding to low Atlantic foraminiferal ^18O (indicating low sea surface density). This matches the modern situation on the interdecadal time-scale, where a warm Indian Ocean leads to a shift of the NAO towards a positive mean state, which is accompanied by SST warming over much of the low- and mid-latitude western Atlantic and a displacement of the Gulf Stream path. We hypothesize that this mechanism also operates on millennial time-scales to explain the obvious similarities in the SST patterns observed in the Northwest Atlantic and western

  14. Novel Use of Hydroxyurea in an African Region With Malaria: Protocol for a Randomized Controlled Clinical Trial

    PubMed Central

    Anyanwu, Juliana N; Williams, Olatundun; Sautter, Casey L; Kasirye, Phillip; Hume, Heather; Opoka, Robert O; Latham, Teresa; Ndugwa, Christopher; Ware, Russell E

    2016-01-01

    Background Sickle cell anemia (SCA), one of most prevalent monogenic diseases worldwide, is caused by a glutamic acid to valine substitution on the beta globin protein of hemoglobin, which leads to hemolytic anemia. Hydroxyurea, the only disease-modifying therapy approved by the Food and Drug Administration for SCA, has proven to be a viable therapeutic option for SCA patients in resource-rich settings, given clinical improvements experienced while taking the medication and its once-daily oral dosing. Significant studies have demonstrated its safety and clinical efficacy among children and adults in developed countries. In Sub-Saharan Africa, however, the risk of malaria, hematologic toxicities, and safety of hydroxyurea in children with SCA living in malaria-endemic areas are unknown. Objectives Study objectives include determining the incidence of malaria in SCA patients taking hydroxyurea versus placebo; establishing the frequency of hematologic toxicities and adverse events (AEs) in children with SCA treated with hydroxyurea versus placebo; and defining the relationships between hydroxyurea treatment and fetal hemoglobin, soluble intracellular adhesion molecule-1, and nitric oxide levels, and between levels of these factors and risk of subsequent malaria. Methods Novel use Of Hydroxyurea in an African Region with Malaria (NOHARM, NCT01976416) is a prospective, randomized, placebo-controlled, double-blinded phase III trial to compare risk of malaria with oral hydroxyurea versus placebo. Children will be recruited from the Mulago Hospital Sickle Cell Clinic in Kampala, Uganda. Results Two hundred Ugandan children aged between 1.00 and 3.99 years with confirmed SCA will be randomized into treatment groups by order of entry in the study, based on a predetermined blinded randomization list. The primary outcome of the trial is malaria incidence in the 2 study groups, defined as episodes of clinical malaria occurring over the 1-year randomized study treatment period

  15. Elimination of mother-to-child transmission of HIV and syphilis: A dual approach in the African Region to improve quality of antenatal care and integrated disease control.

    PubMed

    Newman Owiredu, Morkor; Newman, Lori; Nzomo, Theresa; Conombo Kafando, Ghislaine; Sanni, Saliyou; Shaffer, Nathan; Bucagu, Maurice; Peeling, Rosanna; Mark, Jennifer; Diop Toure, Isseu

    2015-06-01

    The World Health Organization's (WHO) Strategic Framework for the Elimination of New HIV Infections among Children in Africa by 2015 identifies important synergies for the elimination of mother-to-child transmission of HIV and syphilis in terms of prevention interventions, implementation logistics and service delivery, monitoring and evaluation systems, and need for sustained political commitment. The WHO advocates the use of an integrated, rights-based dual approach with partnerships and collaboration to make the best use of available resources. Through a consultative approach, six countries in the African Region committed to dual elimination and developed and implemented action plans for this purpose. Where interest and commitment are high, this may also be possible and effective in other African countries. PMID:25963908

  16. The Paternal Landscape along the Bight of Benin – Testing Regional Representativeness of West-African Population Samples Using Y-Chromosomal Markers

    PubMed Central

    Larmuseau, Maarten H. D.; Vessi, Andrea; Jobling, Mark A.; Van Geystelen, Anneleen; Primativo, Giuseppina; Biondi, Gianfranco; Martínez-Labarga, Cristina; Ottoni, Claudio; Decorte, Ronny; Rickards, Olga

    2015-01-01

    Patterns of genetic variation in human populations across the African continent are still not well studied in comparison with Eurasia and America, despite the high genetic and cultural diversity among African populations. In population and forensic genetic studies a single sample is often used to represent a complete African region. In such a scenario, inappropriate sampling strategies and/or the use of local, isolated populations may bias interpretations and pose questions of representativeness at a macrogeographic-scale. The non-recombining region of the Y-chromosome (NRY) has great potential to reveal the regional representation of a sample due to its powerful phylogeographic information content. An area poorly characterized for Y-chromosomal data is the West-African region along the Bight of Benin, despite its important history in the trans-Atlantic slave trade and its large number of ethnic groups, languages and lifestyles. In this study, Y-chromosomal haplotypes from four Beninese populations were determined and a global meta-analysis with available Y-SNP and Y-STR data from populations along the Bight of Benin and surrounding areas was performed. A thorough methodology was developed allowing comparison of population samples using Y-chromosomal lineage data based on different Y-SNP panels and phylogenies. Geographic proximity turned out to be the best predictor of genetic affinity between populations along the Bight of Benin. Nevertheless, based on Y-chromosomal data from the literature two population samples differed strongly from others from the same or neighbouring areas and are not regionally representative within large-scale studies. Furthermore, the analysis of the HapMap sample YRI of a Yoruban population from South-western Nigeria based on Y-SNPs and Y-STR data showed for the first time its regional representativeness, a result which is important for standard population and forensic genetic applications using the YRI sample. Therefore, the uniquely

  17. The Paternal Landscape along the Bight of Benin - Testing Regional Representativeness of West-African Population Samples Using Y-Chromosomal Markers.

    PubMed

    Larmuseau, Maarten H D; Vessi, Andrea; Jobling, Mark A; Van Geystelen, Anneleen; Primativo, Giuseppina; Biondi, Gianfranco; Martínez-Labarga, Cristina; Ottoni, Claudio; Decorte, Ronny; Rickards, Olga

    2015-01-01

    Patterns of genetic variation in human populations across the African continent are still not well studied in comparison with Eurasia and America, despite the high genetic and cultural diversity among African populations. In population and forensic genetic studies a single sample is often used to represent a complete African region. In such a scenario, inappropriate sampling strategies and/or the use of local, isolated populations may bias interpretations and pose questions of representativeness at a macrogeographic-scale. The non-recombining region of the Y-chromosome (NRY) has great potential to reveal the regional representation of a sample due to its powerful phylogeographic information content. An area poorly characterized for Y-chromosomal data is the West-African region along the Bight of Benin, despite its important history in the trans-Atlantic slave trade and its large number of ethnic groups, languages and lifestyles. In this study, Y-chromosomal haplotypes from four Beninese populations were determined and a global meta-analysis with available Y-SNP and Y-STR data from populations along the Bight of Benin and surrounding areas was performed. A thorough methodology was developed allowing comparison of population samples using Y-chromosomal lineage data based on different Y-SNP panels and phylogenies. Geographic proximity turned out to be the best predictor of genetic affinity between populations along the Bight of Benin. Nevertheless, based on Y-chromosomal data from the literature two population samples differed strongly from others from the same or neighbouring areas and are not regionally representative within large-scale studies. Furthermore, the analysis of the HapMap sample YRI of a Yoruban population from South-western Nigeria based on Y-SNPs and Y-STR data showed for the first time its regional representativeness, a result which is important for standard population and forensic genetic applications using the YRI sample. Therefore, the uniquely

  18. The self-organizing map, a new approach to apprehend the Madden-Julian Oscillation influence on the intraseasonal variability of rainfall in the southern African region

    NASA Astrophysics Data System (ADS)

    Oettli, Pascal; Tozuka, Tomoki; Izumo, Takeshi; Engelbrecht, Francois A.; Yamagata, Toshio

    2014-09-01

    The Madden-Julian Oscillation (MJO) is the major mode of intraseasonal variability (30-60 days) in the tropics, having large rainfall impacts globally, and possibly on southern Africa. However, the latter impact is not well understood and needs to be further explored. The life cycle of the MJO, known to be asymmetric, has been nevertheless analyzed usually through methods constrained by both linearity and orthogonality, such as empirical orthogonal function analysis. Here we explore a non-linear classification method, the self-organizing map (SOM), a type of artificial neural network used to produce a low-dimensional representation of high-dimensional datasets, to capture more accurately the life cycle of the MJO and its global impacts. The classification is applied on intraseasonal anomalies of outgoing longwave radiation within the tropical region over the 1980-2009 period. Using the SOM to describe the MJO is a new approach, complimentary to the usual real-time multivariate MJO index. It efficiently captures this propagative phenomenon and its seasonality, and is shown to provide additional temporal and spatial information on MJO activity. For each node, the subtropical convection is analyzed, with a particular focus on the southern Africa region. Results show that the convection activity over the central tropical Indian Ocean is a key factor influencing the intraseasonal convective activity over the southern African region. Enhanced (suppressed) convection over the central Indian Ocean tends to suppress (enhance) convection over the southern African region with a 10-day lag by modulating the moisture transport.

  19. Using the ``blue spike'' to characterize biomass-burning sites during Southern African Regional Science Initiative (SAFARI) 2000

    NASA Astrophysics Data System (ADS)

    McCourt, M. L.; McMillan, W. W.; Ackerman, S.; Holz, R.; Revercomb, H. E.; Tobin, D.

    2004-10-01

    During several flights of the ER-2 while participating in the Southern African Regional Science Initiative (SAFARI 2000), the University of Wisconsin-Madison's Scanning High Resolution Interferometer Sounder (S-HIS) obtained spectra containing isolated fires within its field of view (FOV). These fire-laden FOVs contain a spectral feature caused by rotational hot band transitions of CO2 near 2400 cm-1. Because of its location on the blue side of the 4.3 μm band of CO2, this feature is commonly referred to as the "blue spike." Using this feature, we detected fires on four flights: 24 and 27 August and 6 and 7 September 2000. Fire locations are further verified by the ER-2 pilot's flight logs and elevated brightness temperatures in the thermal detectors of the MODIS Airborne Simulator (MAS) also on board the ER-2. Using line-by-line radiative transfer calculations (Genln2) with corrections for a fire's extreme high temperatures (HiTemp), we model S-HIS spectra for various scenes: background (cool surface and cool atmosphere), smoldering (warm surface and cool atmosphere), hot gas layer (cool surface and warm atmosphere), and fire (hot surface and hot atmosphere) cases. Using the controlled burn in the Timbavati Game Reserve on 7 September 2000 as a test case, we spectrally modeled the blue spike feature seen in the spectra obtained by S-HIS while the ER-2 flew over the fire. For this case, we found that ˜4.12 ± 0.05% of the FOV contained the hot gas layer while ˜0.23 ± 0.05% was actively burning. Originally viewed as a straightforward task of using the blue spike to characterize the fire temperature and size (fraction of S-HIS FOV), our analysis shows that numerous variables, including amount of carbon dioxide, amount of water vapor, and the temperature near the fire, play significant roles in the blue spike's shape and spectral position.

  20. World City/Regional City: Latinos and African-Americans in Chicago and St. Louis. JSRI Working Paper No. 46.

    ERIC Educational Resources Information Center

    Villanueva, Margaret; Erdman, Brian; Howlett, Larry

    This paper traces the effects of economic restructuring through comparative socioeconomic profiles of African American and Latinos in the Midwest, with a focus on Chicago and Kansas City. Globalization has been associated with deindustrialization, relocation of jobs to developing countries with cheaper labor, and expansion of the service sector. A…

  1. The Rising Burden of Diabetes and Hypertension in Southeast Asian and African Regions: Need for Effective Strategies for Prevention and Control in Primary Health Care Settings

    PubMed Central

    Mohan, Viswanathan; Seedat, Yackoob K.; Pradeepa, Rajendra

    2013-01-01

    Aim. To review the available literature on burden of diabetes mellitus (DM) and hypertension (HTN) and its coexistence in Southeast Asian (SEA) and the African (AFR) regions and to suggest strategies to improve DM and HTN prevention and control in primary health care (PHC) in the two regions. Methods. A systematic review of the papers published on DM, HTN, and prevention/control of chronic diseases in SEA and AFR regions between 1980 and December 2012 was included. Results. In the year 2011, SEA region had the second largest number of people with DM (71.4 million), while the AFR region had the smallest number (14.7 million). Screening studies identified high proportions (>50%) of individuals with previously undiagnosed HTN and DM in both of the SEA and AFR regions. Studies from both regions have shown that DM and HTN coexist in type 2 DM ranging from 20.6% in India to 78.4% in Thailand in the SEA region and ranging from 9.7% in Nigeria to 70.4% in Morocco in the AFR region. There is evidence that by lifestyle modification both DM and HTN can be prevented. Conclusion. To meet the twin challenge of DM and HTN in developing countries, PHCs will have to be strengthened with a concerted and multipronged effort to provide promotive, preventive, curative, and rehabilitative services. PMID:23573413

  2. The VP2 variable region of African and German isolates of infectious bursal disease virus: comparison with very virulent, "classical" virulent, and attenuated tissue culture-adapted strains.

    PubMed

    Zierenberg, K; Nieper, H; van den Berg, T P; Ezeokoli, C D; Voss, M; Müller, H

    2000-01-01

    11 African and two German IBDV strains isolated in the mid '80s from field outbreaks in vaccinated and unvaccinated chicken flocks displayed features of very virulent (vv) IBDV strains. The sequence data of the VP2 variable region and phylogenetic analysis confirm that these strains can be grouped within vv IBDV strains which appeared at the same time on the three continents Africa, Asia, and Europe. Strain Cu-1wt, responsible for severe IBD outbreaks in Germany 13 years earlier, showed some relatedness to these strains, but also significant differences at the genomic level, even though this strain has also features of the vv IBDV strains. PMID:10664410

  3. Reduced-Median-Network Analysis of Complete Mitochondrial DNA Coding-Region Sequences for the Major African, Asian, and European Haplogroups

    PubMed Central

    Herrnstadt, Corinna; Elson, Joanna L.; Fahy, Eoin; Preston, Gwen; Turnbull, Douglass M.; Anderson, Christen; Ghosh, Soumitra S.; Olefsky, Jerrold M.; Beal, M. Flint; Davis, Robert E.; Howell, Neil

    2002-01-01

    The evolution of the human mitochondrial genome is characterized by the emergence of ethnically distinct lineages or haplogroups. Nine European, seven Asian (including Native American), and three African mitochondrial DNA (mtDNA) haplogroups have been identified previously on the basis of the presence or absence of a relatively small number of restriction-enzyme recognition sites or on the basis of nucleotide sequences of the D-loop region. We have used reduced-median-network approaches to analyze 560 complete European, Asian, and African mtDNA coding-region sequences from unrelated individuals to develop a more complete understanding of sequence diversity both within and between haplogroups. A total of 497 haplogroup-associated polymorphisms were identified, 323 (65%) of which were associated with one haplogroup and 174 (35%) of which were associated with two or more haplogroups. Approximately one-half of these polymorphisms are reported for the first time here. Our results confirm and substantially extend the phylogenetic relationships among mitochondrial genomes described elsewhere from the major human ethnic groups. Another important result is that there were numerous instances both of parallel mutations at the same site and of reversion (i.e., homoplasy). It is likely that homoplasy in the coding region will confound evolutionary analysis of small sequence sets. By a linkage-disequilibrium approach, additional evidence for the absence of human mtDNA recombination is presented here. PMID:11938495

  4. The second African Federation of Neurological Surgeons course in the East, Central, and Southern Africa region held in Dar es Salaam, Tanzania, January 2011.

    PubMed

    Kahamba, Joseph F; Assey, Anthony B; Dempsey, Robert J; Qureshi, Mahmood M; Härtl, Roger

    2013-01-01

    The second International African Federation of Neurological Surgeons course was organized on January 24 to 28, 2011, at the Seacliff Hotel and Muhimbili Orthopaedic Institute in Dar es Salaam, Tanzania. President Jakaya Mrisho Kikwete graced the official opening with high ranking government officials in attendance. The targeted participants were young neurosurgeons in the East, Central, and South African region. More than 80 surgeons, residents, and neurosurgical nurses came from Tanzania, Kenya, Uganda, Rwanda, Ethiopia, Zambia, and Zimbabwe. The objectives of the course were to teach and train young local surgeons in the essential-relevant for the region-and current techniques and management principles of brain and spinal diseases, acquire new skills through hands-on practical sessions, and share experiences. The course consisted of didactic sessions, practical aspects on spine internal fixation, cadaver dissections, and live microscopic and endoscopic surgery. Experienced faculty from different states of the United States, Spain, Turkey, India, Egypt, and Ethiopia facilitated the course. The objectives of the course were met with a favorable evaluation report. The collaboration and experience gained will be reinvested in organizing similar courses in the region. PMID:22120325

  5. History and origin of the HIV-1 subtype C epidemic in South Africa and the greater southern African region

    PubMed Central

    Wilkinson, Eduan; Engelbrecht, Susan; de Oliveira, Tulio

    2015-01-01

    HIV has spread at an alarming rate in South Africa, making it the country with the highest number of HIV infections. Several studies have investigated the histories of HIV-1 subtype C epidemics but none have done so in the context of social and political transformation in southern Africa. There is a need to understand how these processes affects epidemics, as socio-political transformation is a common and on-going process in Africa. Here, we genotyped strains from the start of the epidemic and applied phylodynamic techniques to determine the history of the southern Africa and South African epidemic from longitudinal sampled data. The southern African epidemic’s estimated dates of origin was placed around 1960 (95% HPD 1956–64), while dynamic reconstruction revealed strong growth during the 1970s and 80s. The South African epidemic has a similar origin, caused by multiple introductions from neighbouring countries, and grew exponentially during the 1980s and 90s, coinciding with socio-political changes in South Africa. These findings provide an indication as to when the epidemic started and how it has grown, while the inclusion of sequence data from the start of the epidemic provided better estimates. The epidemic have stabilized in recent years with the expansion of antiretroviral therapy. PMID:26574165

  6. Mitochondrial DNA control region sequence variation suggests an independent origin of an {open_quotes}Asian-specific{close_quotes} 9-bp deletion in Africans

    SciTech Connect

    Soodyall, H.; Redd, A.; Vigilant

    1994-09-01

    The intergenic noncoding region between the cytochrome oxidase II and lysyl tRNA genes of human mitochondrial DNA (mtDNA) is associated with two tandemly arranged copies of a 9-bp sequence. A deletion of one of these repeats has been found at varying frequencies in populations of Asian descent, and is commonly referred to as an {open_quotes}Asian-specific{close_quotes} marker. We report here that the 9-bp deletion is also found at a frequency of 10.2% (66/649) in some indigenous African populations, with frequencies of 28.6% (20/70) in Pygmies, 26.6% (12/45) in Malawians and 15.4% (31/199) in southeastern Bantu-speaking populations. The deletion was not found in 123 Khoisan individuals nor in 209 western Bantu-speaking individuals, with the exception of 3 individuals from one group that was admixed with Pygmies. Sequence analysis of the two hypervariable segments of the mtDNA control region reveals that the types associated with the African 9-bp deletion are different from those found in Asian-derived populations with the deletion. Phylogenetic analysis separates the {open_quotes}African{close_quotes} and {open_quotes}Asian{close_quotes} 9-bp deletion types into two different clusters which are statistically supported. Mismatch distributions based on the number of differences between pairs of mtDNA types are consistent with this separation. These findings strongly support the view that the 9-bp deletion originated independently in Africa and in Asia.

  7. Comparative Transcriptomics of Eastern African Cichlid Fishes Shows Signs of Positive Selection and a Large Contribution of Untranslated Regions to Genetic Diversity

    PubMed Central

    Baldo, Laura; Santos, M.Emília; Salzburger, Walter

    2011-01-01

    The hundreds of endemic species of cichlid fishes in the East African Great Lakes Tanganyika, Malawi, and Victoria are a prime model system in evolutionary biology. With five genomes currently being sequenced, eastern African cichlids also represent a forthcoming genomic model for evolutionary studies of genotype-to-phenotype processes in adaptive radiations. Here we report the functional annotation and comparative analyses of transcriptome data sets for two eastern African cichlid species, Astatotilapia burtoni and Ophthalmotilapia ventralis, representatives of the modern haplochromines and ectodines, respectively. Nearly 647,000 expressed sequence tags were assembled in more than 46,000 contigs for each species using the 454 sequencing technology, largely expanding the current sequence data set publicly available for these cichlids. Total predicted coverage of their proteome diversity is approximately 50% for both species. Comparative qualitative and quantitative analyses show very similar transcriptome data for the two species in terms of both functional annotation and relative abundance of gene ontology terms expressed. Average genetic distance between species is 1.75% when all transcript types are considered including nonannotated sequences, 1.33% for annotated sequences only including untranslated regions, and decreases to nearly half, 0.95%, for coding sequences only, suggesting a large contribution of noncoding regions to their genetic diversity. Comparative analyses across the two species, tilapia and the outgroup medaka based on an overlapping data set of 1,216 genes (∼526 kb) demonstrate cichlid-specific signature of disruptive selection and provide a set of candidate genes that are putatively under positive selection. Overall, these data sets offer the genetic platform for future comparative analyses in light of the upcoming genomes for this taxonomic group. PMID:21617250

  8. A conserved African swine fever virus right variable region gene, l11L, is non-essential for growth in vitro and virulence in domestic swine.

    PubMed

    Kleiboeker, S B; Kutish, G F; Neilan, J G; Lu, Z; Zsak, L; Rock, D L

    1998-05-01

    The right variable region of the African swine fever virus (ASFV) genome is known to contain genes with functions involving virus virulence and host range in swine. A novel open reading frame, ORF l11L, which was absent in the non-pathogenic, cell culture-adapted European isolate BA71V, was identified in the pathogenic African isolate Malawi Lil-20/1. The location of l11L in the right variable region, together with its absence in BA71V, suggested that l11L may have a function in virus virulence and/or host range. Here, we show that the l11L gene is highly conserved among pathogenic African, European and Caribbean ASFV field isolates and that it exists either in a short form, encoding a protein of 77-78 amino acids (9.1 kDa) or in a longer form of 93-94 amino acids (11.1 kDa). The presence of two predicted membrane-spanning segments suggests that l11L is an integral membrane protein. RT-PCR analysis demonstrated that l11L mRNA is expressed late in the virus replication cycle. A recombinant l11L gene deletion mutant, deltal11L, was constructed from the ASFV isolate Malawi Lil-20/1 to examine gene function. Deletion of l11L did not affect virus replication in swine macrophage cell cultures nor virulence in domestic pigs, indicating that l11L is non-essential for growth in vitro and for virus virulence in domestic swine. PMID:9603334

  9. A Polymorphism in the Regulatory Region of the CC-Chemokine Receptor 5 Gene Influences Perinatal Transmission of Human Immunodeficiency Virus Type 1 to African-American Infants

    PubMed Central

    Kostrikis, Leondios G.; Neumann, Avidan U.; Thomson, Bruce; Korber, Bette T.; McHardy, Paul; Karanicolas, Rose; Deutsch, Lisa; Huang, Yaoxing; Lew, Judy F.; McIntosh, Kenneth; Pollack, Henry; Borkowsky, William; Spiegel, Hans M. L.; Palumbo, Paul; Oleske, James; Bardeguez, Arlene; Luzuriaga, Katherine; Sullivan, John; Wolinsky, Steven M.; Koup, Richard A.; Ho, David D.; Moore, John P.

    1999-01-01

    There are natural mutations in the coding and noncoding regions of the human immunodeficiency virus type 1 (HIV-1) CC-chemokine coreceptor 5 (CCR5) and in the related CCR2 protein (the CCR2-64I mutation). Individuals homozygous for the CCR5-Δ32 allele, which prevents CCR5 expression, strongly resist HIV-1 infection. Several genetic polymorphisms have been identified within the CCR5 5′ regulatory region, some of which influence the rate of disease progression in adult AIDS study cohorts. We genotyped 1,442 infants (1,235 uninfected and 207 HIV-1 infected) for five CCR5 and CCR2 polymorphisms: CCR5-59353-T/C, CCR5-59356-C/T CCR5-59402-A/G, CCR5-Δ32, and CCR2-64I. The clinical significance of each genotype was assessed by measuring whether it influenced the rate of perinatal HIV-1 transmission among 667 AZT-untreated mother-infant pairs (554 uninfected and 113 HIV-1 infected). We found that the mutant CCR5-59356-T allele is relatively common in African-Americans (20.6% allele frequency among 552 infants) and rare in Caucasians and Hispanics (3.4 and 5.6% of 174 and 458 infants, respectively; P < 0.001). There were 38 infants homozygous for CCR5-59356-T, of whom 35 were African-Americans. Among the African-American infants in the AZT-untreated group, there was a highly significant increase in HIV-1 transmission to infants with two mutant CCR5-59356-T alleles (47.6% of 21), compared to those with no or one mutant allele (13.4 to 14.1% of 187 and 71, respectively; P < 0.001). The increased relative risk was 5.9 (95% confidence interval, 2.3 to 15.3; P < 0.001). The frequency of the CCR5-59356-T mutation varies between population groups in the United States, a low frequency occurring in Caucasians and a higher frequency occurring in African-Americans. Homozygosity for CCR5-59356-T is strongly associated with an increased rate of perinatal HIV-1 transmission. PMID:10559343

  10. The West African monsoon: Contribution of the AMMA multidisciplinary programme to the study of a regional climate system.

    NASA Astrophysics Data System (ADS)

    Lebel, T.; Janicot, S.; Redelsperger, J. L.; Parker, D. J.; Thorncroft, C. D.

    2015-12-01

    The AMMA international project aims at improving our knowledge and understanding of the West African monsoon and its variability with an emphasis on daily-to-interannual timescales. AMMA is motivated by an interest in fundamental scientific issues and by the societal need for improved prediction of the WAM and its impacts on water resources, health and food security for West African nations. The West African monsoon (WAM) has a distinctive annual cycle in rainfall that remains a challenge to understand and predict. The location of peak rainfall, which resides in the Northern Hemisphere throughout the year, moves from the ocean to the land in boreal spring. Around the end of June there is a rapid shift in the location of peak rainfall between the coast and around 10°N where it remains until about the end of August. In September the peak rainfall returns equatorward at a relatively steady pace and is located over the ocean again by November. The fact that the peak rainfall migrates irregularly compared to the peak solar heating is due to the interactions that occur between the land, the atmosphere and the ocean. To gain a better understanding of this complex climate system, a large international research programme was launched in 2002, the biggest of its kind into environment and climate ever attempted in Africa. AMMA has involved a comprehensive field experiment bringing together ocean, land and atmospheric measurements, on timescales ranging from hourly and daily variability up to the changes in seasonal activity over a number of years. This presentation will focus on the description of the field programme and its accomplishments, and address some key questions that have been recently identified to form the core of AMMA-Phase 2.

  11. The West African monsoon: Contribution of the AMMA multidisciplinary programme to the study of a regional climate system.

    NASA Astrophysics Data System (ADS)

    Lebel, T.; Janicot, S.; Redelsperger, J. L.; Parker, D. J.; Thorncroft, C. D.

    2014-12-01

    The AMMA international project aims at improving our knowledge and understanding of the West African monsoon and its variability with an emphasis on daily-to-interannual timescales. AMMA is motivated by an interest in fundamental scientific issues and by the societal need for improved prediction of the WAM and its impacts on water resources, health and food security for West African nations. The West African monsoon (WAM) has a distinctive annual cycle in rainfall that remains a challenge to understand and predict. The location of peak rainfall, which resides in the Northern Hemisphere throughout the year, moves from the ocean to the land in boreal spring. Around the end of June there is a rapid shift in the location of peak rainfall between the coast and around 10°N where it remains until about the end of August. In September the peak rainfall returns equatorward at a relatively steady pace and is located over the ocean again by November. The fact that the peak rainfall migrates irregularly compared to the peak solar heating is due to the interactions that occur between the land, the atmosphere and the ocean. To gain a better understanding of this complex climate system, a large international research programme was launched in 2002, the biggest of its kind into environment and climate ever attempted in Africa. AMMA has involved a comprehensive field experiment bringing together ocean, land and atmospheric measurements, on timescales ranging from hourly and daily variability up to the changes in seasonal activity over a number of years. This presentation will focus on the description of the field programme and its accomplishments, and address some key questions that have been recently identified to form the core of AMMA-Phase 2.

  12. The role of conflict minerals, artisanal mining, and informal trading networks in African intrastate and regional conflicts

    USGS Publications Warehouse

    Chirico, Peter G.; Malpeli, Katherine C.

    2014-01-01

    The relationship between natural resources and armed conflict gained public and political attention in the 1990s, when it became evident that the mining and trading of diamonds were connected with brutal rebellions in several African nations. Easily extracted resources such as alluvial diamonds and gold have been and continue to be exploited by rebel groups to fund their activities. Artisanal and small-scale miners operating under a quasi-legal status often mine these mineral deposits. While many African countries have legalized artisanal mining and established flow chains through which production is intended to travel, informal trading networks frequently emerge in which miners seek to evade taxes and fees by selling to unauthorized buyers. These networks have the potential to become international in scope, with actors operating in multiple countries. The lack of government control over the artisanal mining sector and the prominence of informal trade networks can have severe social, political, and economic consequences. In the past, mineral extraction fuelled violent civil wars in Sierra Leone, Liberia, and Angola, and it continues to do so today in several other countries. The significant influence of the informal network that surrounds artisanal mining is therefore an important security concern that can extend across borders and have far-reaching impacts.

  13. Mesoscale modeling and satellite observation of transport and mixing of smoke and dust particles over northern sub-Saharan African region

    NASA Astrophysics Data System (ADS)

    Yang, Zhifeng; Wang, Jun; Ichoku, Charles; Hyer, Edward; Zeng, Jing

    2013-11-01

    transport and vertical distribution of smoke and dust aerosols over the northern sub-Saharan African region are simulated in the Weather Research and Forecasting model with Chemistry (WRF-Chem), which uses hourly dynamic smoke emissions from the Fire Locating and Modeling of Burning Emissions database derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) fire products. Model performance for February 2008 is evaluated using MODIS true color images, aerosol optical depth (AOD) measurements from the Aerosol Robotic Network, MODIS AOD retrievals, and the Cloud-Aerosol Lidar data with Orthogonal Polarization (CALIOP) atmospheric backscattering and extinction products. Specification of smoke injection height of 650 m in WRF-Chem yields aerosol vertical profiles that are most consistent with CALIOP observations of aerosol layer height. Between the equator and 10°N, Saharan dust is often mixed with smoke near the surface, and their transport patterns manifest the interplay of trade winds, subtropical highs, precipitation associated with the Intertropical Convergence Zone, and the high mountains located near the Great Rift Valley region. At the 700 hPa level and above, smoke layers spread farther to the north and south and are often above the dust layers over the Sahel region. In some cases, transported smoke can also be mixed with dust over the Saharan region. Statistically, 5% of the CALIOP valid measurements in February 2007-2011 show aerosol layers either above or between the clouds, reinforcing the importance of the aerosol vertical distribution for quantifying aerosol impact on climate in the Sahel region.

  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. Astronomy for African development

    NASA Astrophysics Data System (ADS)

    Govender, Kevindran

    2011-06-01

    In recent years there have been a number of efforts across Africa to develop the field of astronomy as well as to reap benefit from astronomy for African people. This presentation will discuss the case of the SALT (Southern African Large Telescope) Collateral Benefits Programme (SCBP) which was set up to ensure societal benefit from astronomy. With African society as the target, the SCBP has embarked on various projects from school level education to public understanding of science to socio-economic development, the latter mainly being felt in the rural communities surrounding the South African Astronomical Observatory (home to SALT). A development plan for ``Astronomy in Africa'' will also be discussed. This plan has been drawn up with input from all over Africa and themed ``Astronomy for Education''. The Africa case stands as a good example for the IYA cornerstone project ``Developing Astronomy Globally'' which focuses on developing regions.

  16. Using solar wind data to predict daily GPS scintillation occurrence in the African and Asian low-latitude regions

    NASA Astrophysics Data System (ADS)

    Carter, B. A.; Retterer, J. M.; Yizengaw, E.; Wiens, K.; Wing, S.; Groves, K.; Caton, R.; Bridgwood, C.; Francis, M.; Terkildsen, M.; Norman, R.; Zhang, K.

    2014-12-01

    The feasibility of predicting the daily occurrence of Global Positioning System scintillation events using forecasts of common geophysical indices to drive a physics-based model of the system is demonstrated over a 5 month period for the African and Asian longitude sectors. The output from the Wing Kp model, which uses solar wind data to predict the geomagnetic activity level up to 4 h in advance, was used to drive the National Center for Atmospheric Research thermosphere/ionosphere model, from which the strength of the Rayleigh-Taylor instability growth rate was calculated to determine the likelihood of scintillation. It is found that the physics-based model demonstrates superior skill to an empirical scintillation model (Wideband Model (WBMOD)) in forecasting scintillation suppression events during seasons when scintillation is common. However, neither of the models driven in this way possess the ability to forecast isolated scintillation events during transitional and off-peak seasons.

  17. The Thermal History of the East African Rift Lakes Region Since the Last Glacial Maximum Using TEX86 Paleothermometry

    NASA Astrophysics Data System (ADS)

    Berke, M. A.; Johnson, T. C.; Werne, J. P.; Schouten, S.; Sinninghe Damsté, J. S.

    2008-12-01

    We present preliminary results from a study using the TEX86 temperature proxy from sediments of East African Rift Lakes (including Lakes Turkana, Albert, and Malawi) to reconstruct the thermal history of tropical Africa for the last ~ 20,000 years at a subcentennial to multicentennial resolution. The TEX86 proxy, based on tetraether membrane lipids produced by lacustrine Crenarchaeota, has been shown to be successful at recording lake surface temperatures of some large lakes, including Lakes Malawi and Tanganyika, while providing unreasonable surface temperatures for lakes that receive a large input of soil material. The East African Rift Lakes are climatically sensitive, with the majority of water loss due to evaporation rather than outflow. Thus, they are useful for paleoclimate studies, being sensitive to even small changes in aridity. Temperature records from the northern and central basins of Lake Malawi agree well and fall within modern surface lake temperatures. A 2.5°C cooling is evident during the Younger Dryas in the northern basin record, with no response seen in the central basin. We are currently investigating mechanisms to explain why both records show a gradual cooling of 3°C during the late Holocene. Lake Albert shows an intriguing two-step cooling during the Younger Dryas, reaching temperatures 2.5°C lower than temperatures preceding or following this interval. The temperature record of Lake Turkana shows an interesting ~ 500 year cyclicity of low temperatures punctuated by abrupt warming events. Lakes Turkana and Albert show TEX86 paleotemperatures considerably lower (8°C cooler in Lake Albert and ~ 4°C cooler in Lake Turkana) than modern surface water temperatures. Although these records appear to fall in the range of temporal variability, these temperature discrepancies may indicate varying Crenarcheotal populations between lakes or other influencing factors.

  18. High-resolution regional modeling of summertime transport and impact of African dust over the Red Sea and Arabian Peninsula

    NASA Astrophysics Data System (ADS)

    Kalenderski, Stoitchko; Stenchikov, Georgiy

    2016-06-01

    Severe dust outbreaks and high dust loading over Eastern Africa and the Red Sea are frequently detected in the summer season. Observations suggest that small-scale dynamic and orographic effects, from both the Arabian and African sides, strongly contribute to dust plume formation. To better understand these processes, we present here the first high-resolution modeling study of a dust outbreak in June 2012 developed over East Africa, the Red Sea, and the Arabian Peninsula. Using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) component, we identified several dust generating dynamical processes that range from convective to synoptic scales, including synoptic cyclones, nocturnal low-level jets, and cold pools of mesoscale convective systems. The simulations reveal an eastward transport of African dust across the Red Sea. Over the northern part of the Red Sea, most of the dust transport occurs above 2 km height, whereas across the central and southern parts of the sea; dust is mostly transported below 2 km height. Dust is the dominant contributor (87%) to the aerosol optical depth, producing a domain average cooling effect of -12.1 W m-2 at the surface, a warming of 7.1 W m-2 in the atmosphere, and a residual cooling of -4.9 W m-2 at the top of the atmosphere. Both dry and wet deposition processes contribute significantly to dust removal from the atmosphere. Model results compare well with available ground-based and satellite observations but generally underestimate the observed maximum values of aerosol optical depth. The satellite-retrieved mean optical depth at some locations is underestimated by a factor of 2. A sensitive experiment suggests that these large local differences may result from poor characterization of dust emissions in some areas of the modeled domain. In this case study we successfully simulate the major fine-scale dust generating dynamical processes, explicitly resolving convection and haboob formation. The future

  19. Patterns of GPS-TEC variation over low-latitude regions (African sector) during the deep solar minimum (2008 to 2009) and solar maximum (2012 to 2013) phases

    NASA Astrophysics Data System (ADS)

    Tariku, Yekoye Asmare

    2015-03-01

    Due to the unique geometry of the geomagnetic fields near the magnetic equator and low-latitude regions, the satellite communication system in the African sector is strongly influenced by the effects resulting from the accumulation of electrons in their ionosphere. Hence, this paper investigates the patterns of the vertical total electron content (VTEC) variation detected by the Global Positioning System (GPS) over low-latitude regions during a very low (2008 to 2009) and a high solar activity (2012 to 2013) phases. The study has been carried out by considering eight ground-based dual-frequency GPS receivers installed recently at different regions in Ethiopia. In this work, the diurnal, monthly, and seasonal variations in the GPS-VTEC have been analyzed. It has been found that the diurnal variability of VTEC has shown minimum values at around 0300 UT (0600 local time (LT)) and maximum values nearly between 1000 and 1300 UT (1300 and 1600 LT) during both the low and the high activity phases. Moreover, the maximum and minimum of monthly mean hourly VTEC values are observed in October and July, respectively, during both the low (2009) and the high solar activity (2012) phases. It has also been depicted that seasonal mean hourly VTEC values have shown maxima and minima in the March equinox and the June solstice, respectively, during both the low and the high solar activity phases.

  20. Late Pan-African granite emplacement during regional deformation, evidence from magnetic fabric and structural studies in the Hammamat-Atalla area, Central Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Greiling, R. O.; de Wall, H.; Sadek, M. F.; Dietl, C.

    2014-11-01

    Field investigations, microstructural observations, and magnetic fabric analyses revealed a polyphase, late Pan-African deformational evolution in the Um Sheqila-Um Had (595 Ma) composite pluton and in the Hammamat and Atalla areas of the Central Eastern Desert of Egypt in Ediacaran times. Major stages are early shortening (NNW-SSE), subsequent strike-slip (NW-SE shear zones), and late shortening (NW-SE). Strain studies on pebbles and xenoliths together with AMS data show a predominance of shallow, NW-SE trending X axes or magnetic lineations, associated with steep, NW-SE striking magnetic foliations. Magnetic fabrics and microstructures indicate a tectonic fabric in the Um Sheqila-Um Had granitoid plutons, which is dominated by steep NW-SE striking foliations and shallow NW-SE trending lineations, similar to those in the high-angle Atalla Shear Zone. There is a change of lineation directions from ESE-WNW at Um Sheqila (oldest) to NW-SE to Um Had II (youngest). This pattern may indicate an influence of strike-slip and is also consistent with NE-SW compression. This holds also true for the asymmetry of the contact aureole, which is extended towards NW, parallel with the trend of the magnetic lineation. The character and orientation of the deformation pattern in the Um Sheqila-Um Had plutons and the Atalla Shear Zone is thus similar to the pattern of the late shortening phase. The intrusion of the Um Sheqila-Um Had granitoid rocks, therefore, took place before the late shortening stage, but postdates early deformation, which, according to published data, was associated with lithospheric thinning in the Central Eastern Desert. Therefore, these Pan-African plutons do not represent the earliest post-deformational intrusions but a late stage of syn-deformational magmatic activity. At a regional scale, this deformation with steep foliations and shallow lineations may also be related with lateral escape tectonics. The pluton emplacement, the importance of transcurrent

  1. Using apatite (U-Th)/He thermochronometry to resolve regional unroofing patterns across the interior of the southern African Plateau and implications for mantle dynamics

    NASA Astrophysics Data System (ADS)

    Stanley, J. R.; Flowers, R. M.

    2011-12-01

    plateau interior since Cretaceous time. The only published AHe data for southern Africa (Flowers and Schoene 2009) comes from across the Great Escarpment in the Barberton region of South Africa and Swaziland. Those results are also Cretaceous with dates clustering ~100 Ma. Our new data, when combined with the previously published results, complete a large scale, ~900 km long, transect of AHe data from the coastal plain across the Great Escarpment well into the interior of the plateau. This full dataset suggests an intriguing spatial variability in dates, and shows the promise of using AHe data to decipher unroofing patterns across the continent to help better understand the mantle processes responsible for the rise of the southern African Plateau.

  2. The family planning movement within the African Region of the International Planned Parenthood Federation. Le mouvement pour la planification familiale dans la Region Afrique de la Federation Internationale pour la Planification Familiale.

    PubMed

    Sozi, M K

    1984-09-01

    The African Region of International Planned Parenthood Federation (IPPF) was established in 1971 to: encourage and sustain voluntary groups, provide information about family planning as a basic right, provide limited family planning services where acceptable and needed, and eventually influence change in public opinion so that governments could accept some responsibility for family planning programs. Today almost all of Anglophone Africa is covered by IPPF-funded activities, progress is being made in Francophone Africa, and Lusophone Africa is a target for the 1980s. National family planning associations and the IPPF have laid a firm foundation for family planning and raised its credibility to acceptable levels. However, both inadequate logistic infrastructures for the smooth flow of services and overcaution in adopting innovative methods such as community-based delivery systems to those not easily reached by coventional delivery systems have led service to lag behind demand. Leaders at all levels must join efforts to solve this dilemma. Family planning associations are the best suited channels for family planning work in the African Region, but they lack the capacity to cover all needs. As a result, these associations are shiftingg their efforts toward supplementing government work in this area. Although the government response has been far from uniform, governments have shown an ability to accommodate the operations of family planning organizations and have integrated family planning into national health services. Although 19 governments in the Region consider the fertility levels in their countries to be satisfactory and a few consider fertility too low, family planning is accepted as an instrument for the promotion of family welfare. The importance of national leadership in promoting and implementing family planning programs is increasingly recognized. Parliamentarians can formulate national policies favorable to family planning, promote awareness among their

  3. Structural analysis of the Itapucumí Group in the Vallemí region, northern Paraguay: Evidence of a new Brasiliano/Pan-African mobile belt

    NASA Astrophysics Data System (ADS)

    Campanha, Ginaldo Ademar da Cruz; Warren, Lucas; Boggiani, Paulo César; Grohmann, Carlos Henrique; Cáceres, Alberto Arias

    The Neoproterozoic (Ediacaran) Itapucumí Group in northern Paraguay is composed of carbonate and siliciclastic rocks, including ooid grainstones, marls, shales and sandstones, containing Cloudina fossils in the eastern region. It is almost undeformed over the Rio Apa Cratonic Block but shows a strong deformational pattern at its western edge. A detailed structural analysis of the Itapucumí Group was conducted in the Vallemí Mine, along with a regional survey in other outcrops downstream in the Paraguay River and in the San Alfredo, Cerro Paiva and Sargento José E. López regions. In the main Vallemí quarry, the structural style is characterized by an axial-plane slaty cleavage in open to isoclinal folds, sometimes overturned, associated with N-S trending thrust faults and shear zones of E-vergence and with a low-grade chlorite zone metamorphism. The structural data presented here are compatible with the hypothesis of a newly recognized mobile belt on the western side of the Rio Apa Cratonic Block, with opposite vergence to that of the Paraguay Mobile Belt in Brazil. Both belts are related to the Late Brasiliano/Pan-African tectonic cycle with a Lower Cambrian deformation and metamorphism age. The deformation could be due to the late collision of the Amazonian Craton with the remainder of Western Gondwana or to the western active plate boundary related to the Pampean Belt. The structural and lithologic differences between the western Itapucumí Group in the Vallemí and Paraguay River region and the eastern region, near San Alfredo and Cerro Paiva, suggest that this group could be divided into two lithostratigraphic units, but more stratigraphic and geochronological analyses are required to confirm this possibility.

  4. Geochemistry and isotopic evolution of the central African Domes, Bangweulu and Irumide regions: Evidence for cryptic Archean sources and a Paleoproterozoic continental arc

    NASA Astrophysics Data System (ADS)

    Debruyne, David; Van Wilderode, Jorik; Balcaen, Lieve; Vanhaecke, Frank; Muchez, Philippe

    2014-12-01

    The interregional cratonic relations between the Paleo- and Mesoproterozoic basement units surrounding the Neoproterozoic Central African Copperbelt are still largely unresolved, although they are regarded as major potential metal sources. This study focuses on the Domes region basement at depth below the Copperbelt and its relationship to the neighboring Bangweulu Block and its destabilized margin, the Irumide Belt. We applied an integrated whole rock petrochemical and Sm-Nd isotopic approach to major lithological units to assess the proposed mid-Proterozoic arc setting for the Domes basement inliers along with their relationship to the neighboring areas. The available petrochemical and isotopic data for the Paleoproterozoic eastern Domes granitoids and magmatic units in the SW Bangweulu Block is consistent with a continental arc setting. Moreover, the mid-Paleoproterozoic Nd isotope ratios preclude an island arc because they are significantly less radiogenic than the depleted mantle. Predominantly Archean and Early Paleoproterozoic depleted mantle model ages in all terranes indicate limited juvenile input during Paleo- and Mesoproterozoic magmatic phases. Finally, broadly similar model ages in the Domes inliers and the Bangweulu-Irumide region suggest a relationship between these terranes.

  5. A framework for process-based assessment of regional climate model experiments: applied to projections of southern African precipitation

    NASA Astrophysics Data System (ADS)

    James, Rachel; Washington, Richard; Jones, Richard

    2015-04-01

    There is a demand from adaptation planners for regional climate change projections, particularly the finer resolution data delivered by regional models. However, climate models are subject to important uncertainties, and their projections diverge substantially, particularly for precipitation. So how should decision makers know which futures to consider and which to disregard? Model evaluation is clearly a priority. The majority of studies seeking to assess the validity of projections are based on comparison of the models' twentieth century climatologies with observations or reanalysis. Whilst this work is very important, examination of the modelled mean state it is not sufficient to assess the credibility of modelled changes. Direct investigation of the mechanisms for change is also vital. In this study, a framework for process-based analysis of projections is presented, whereby circulation changes accompanying future responses are examined, and then compared to atmospheric dynamics during historical years in models and reanalyses. This framework has previously been applied to investigate a drying signal in West Africa, and will here be used to examine projected precipitation change in southern Africa. An ensemble of five global and regional model experiments will be employed, consisting of five perturbed versions of HadCM3 and five corresponding runs of HadRM3P (PRECIS), run over the CORDEX Africa domain. The global and regional model runs show contrasting future responses: there is a strong drying in the global models over southern Africa during the rainy season, but the regional models show drying over Madagascar and the south west Indian Ocean. Circulation changes associated with these projections will be presented as a first step towards understanding the mechanisms for change and the reasons for difference between the global and regional models. The interannual variability will also be examined and compared to reanalysis to explore how well the models

  6. Future changes in African temperature and precipitation in an ensemble of Africa-CORDEX regional climate model simulations

    NASA Astrophysics Data System (ADS)

    Kjellström, Erik; Nikulin, Grigory; Gbobaniyi, Emiola; Jones, Colin

    2013-04-01

    In this study we investigate possible changes in temperature and precipitation on a regional scale over Africa from 1961 to 2100. We use data from two ensembles of climate simulations, one global and one regional, over the Africa-CORDEX domain. The global ensemble includes eight coupled atmosphere ocean general circulation models (AOGCMs) from the CMIP5 project with horizontal resolution varying from about 1° to 3°, namely CanESM2, CNRM-CM5, HadGEM2-ES, NorESM1-M, EC-EARTH, MIROC5, GFDL-ESM2M and MPI-ESM-LR. In the regional ensemble all 8 AOGCMs are downscaled at the Rossby Centre (SMHI) by a regional climate model - RCA4 at 0.44° resolution. Two forcing scenarios are considered, RCP 4.5 and 8.5. The experimental setup allows us to illustrate how uncertainties in future climate change are related to forcing scenario and to forcing AOGCM at different time periods. Further, we investigate the benefit of the higher horizontal resolution in RCA4 by comparing the results to the coarser driving AOGCM data. The significance of the results is investigated by comparing to i) the model simulated natural variability, and, ii) the biases in the control period. Results dealing with changes in the seasonal cycle of temperature and precipitation are presented. We also address higher-order variability by showing results for changes in temperature extremes and for changes in intensity and frequency of extreme precipitation.

  7. Association of Socioeconomic Status with Overall and Cause Specific Mortality in the Republic of Seychelles: Results from a Cohort Study in the African Region

    PubMed Central

    Stringhini, Silvia; Rousson, Valentin; Viswanathan, Bharathi; Gedeon, Jude; Paccaud, Fred; Bovet, Pascal

    2014-01-01

    Background Low socioeconomic status (SES) is consistently associated with higher mortality in high income countries. Only few studies have assessed this association in low and middle income countries, mainly because of sparse reliable mortality data. This study explores SES differences in overall and cause-specific mortality in the Seychelles, a rapidly developing small island state in the African region. Methods All deaths have been medically certified over more than two decades. SES and other lifestyle-related risk factors were assessed in a total of 3246 participants from three independent population-based surveys conducted in 1989, 1994 and 2004. Vital status was ascertained using linkage with vital statistics. Occupational position was the indicator of SES used in this study and was assessed with the same questions in the three surveys. Results During a mean follow-up of 15.0 years (range 0–23 years), 523 participants died (overall mortality rate 10.8 per 1000 person-years). The main causes of death were cardiovascular disease (CVD) (219 deaths) and cancer (142 deaths). Participants in the low SES group had a higher mortality risk for overall (HR = 1.80; 95% CI: 1.24–2.62), CVD (HR = 1.95; 1.04–3.65) and non-cancer/non-CVD (HR = 2.14; 1.10–4.16) mortality compared to participants in the high SES group. Cancer mortality also tended to be patterned by SES (HR = 1.44; 0.76–2.75). Major lifestyle-related risk factors (smoking, heavy drinking, obesity, diabetes, hypertension, hypercholesterolemia) explained a small proportion of the associations between low SES and all-cause, CVD, and non-cancer/non-CVD mortality. Conclusions In this population-based study assessing social inequalities in mortality in a country of the African region, low SES (as measured by occupational position) was strongly associated with overall, CVD and non-cancer/non-CVD mortality. Our findings support the view that the burden of non-communicable diseases may

  8. Resolution dependence in simulating the African hydroclimate with the HadGEM3-RA regional climate model

    NASA Astrophysics Data System (ADS)

    Moufouma-Okia, W.; Jones, R.

    2015-02-01

    This study documents the effect of horizontal resolution on the ability of the Met Office third-generation Global Atmosphere Regional Climate Model (HadGEM3-RA), a regional atmospheric configuration of the HadGEM3 model, to simulate rainfall variability over Africa. It is based on six 20-year long RCM simulations driven by ERA-Interim reanalysis and performed at 12, 25, 50, 70, 90, and 150 km over the CORDEX-Africa domain. To gain further insight into model errors, we also compared the HadGEM3-RA's performance to that of the parent General Circulation Model using three different spatial resolutions (70, 100, and 150 km), and to HadRM3P—the current Met Office regional climate model. It is found that the 50 km resolution RCM reproduces reasonably the spatial and temporal features of rainfall variability across regions. These include the seasonal progression of the tropical rainbelt, its extent and location, the annual cycle and interannual variability. Although model biases vary across seasons and locations, a prominent feature is the over-prediction of rainfall totals over Central Africa, and underestimation of rainfall in coastal areas of the Guinea Gulf during boreal spring and autumn. HadGEM3-RA improves with increased horizontal resolution, but some model errors persist. Comparison with the parent global model simulations demonstrates generally a realistic and consistent behaviour over large scales—suggesting that the physical formulation is able to capture the key driving processes, but also confirms the benefit of increasing the model horizontal resolution. Despite the model errors, HadGEM3-RA rainfall shows superiority over that from HadRM3P, ERA-Interim and MERRA datasets—indicating that the associated dynamical features of HadGEM3-RA can complement the physical understanding gained from reanalyses. This article also highlights the challenges for evaluating climate models in data sparse regions where satellite derived rainfall and gridded observational

  9. 9 CFR 94.17 - Dry-cured pork products from regions where foot-and-mouth disease, rinderpest, African swine...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the Federal Meat Inspection Act (21 U.S.C. 601 et seq.) and regulations thereunder (9 CFR, chapter III... where foot-and-mouth disease, rinderpest, African swine fever, classical swine fever, or swine vesicular... RINDERPEST, FOOT-AND-MOUTH DISEASE, EXOTIC NEWCASTLE DISEASE, AFRICAN SWINE FEVER, CLASSICAL SWINE...

  10. 9 CFR 94.17 - Dry-cured pork products from regions where foot-and-mouth disease, rinderpest, African swine...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the Federal Meat Inspection Act (21 U.S.C. 601 et seq.) and regulations thereunder (9 CFR, chapter III... where foot-and-mouth disease, rinderpest, African swine fever, classical swine fever, or swine vesicular... RINDERPEST, FOOT-AND-MOUTH DISEASE, EXOTIC NEWCASTLE DISEASE, AFRICAN SWINE FEVER, CLASSICAL SWINE...

  11. 9 CFR 94.17 - Dry-cured pork products from regions where foot-and-mouth disease, rinderpest, African swine...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... the Federal Meat Inspection Act (21 U.S.C. 601 et seq.) and regulations thereunder (9 CFR, chapter III... where foot-and-mouth disease, rinderpest, African swine fever, classical swine fever, or swine vesicular... RINDERPEST, FOOT-AND-MOUTH DISEASE, EXOTIC NEWCASTLE DISEASE, AFRICAN SWINE FEVER, CLASSICAL SWINE...

  12. 9 CFR 94.17 - Dry-cured pork products from regions where foot-and-mouth disease, rinderpest, African swine...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... (9 CFR, chapter III), including requirements that the pork or pork products be prepared only in... where foot-and-mouth disease, rinderpest, African swine fever, classical swine fever, or swine vesicular... RINDERPEST, FOOT-AND-MOUTH DISEASE, NEWCASTLE DISEASE, HIGHLY PATHOGENIC AVIAN INFLUENZA, AFRICAN SWINE...

  13. 9 CFR 94.17 - Dry-cured pork products from regions where foot-and-mouth disease, rinderpest, African swine...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... the Federal Meat Inspection Act (21 U.S.C. 601 et seq.) and regulations thereunder (9 CFR, chapter III... where foot-and-mouth disease, rinderpest, African swine fever, classical swine fever, or swine vesicular... RINDERPEST, FOOT-AND-MOUTH DISEASE, EXOTIC NEWCASTLE DISEASE, AFRICAN SWINE FEVER, CLASSICAL SWINE...

  14. Africa-U.S. Higher Education Collaboration Initiative: Empowering African Higher Education for Africa's Transformation. A Discussion Paper for the Africa Region Post-Summit Workshop. Working Paper

    ERIC Educational Resources Information Center

    National Association of State Universities and Land-Grant Colleges, 2008

    2008-01-01

    This paper examines how higher education can contribute to Africa's transformation, reviews the challenges and priorities for higher education institution building, and introduces a proposed partnership program among African and U.S. higher education institutions to strengthen African higher education. In July of 2007 the National Association of…

  15. Low Prevalence of Liver Disease but Regional Differences in HBV Treatment Characteristics Mark HIV/HBV Co-Infection in a South African HIV Clinical Trial

    PubMed Central

    Ive, Prudence; MacLeod, William; Mkumla, Nompumelelo; Orrell, Catherine; Jentsch, Ute; Wallis, Carole L.; Stevens, Wendy; Wood, Robin; Sanne, Ian; Bhattacharya, Debika

    2013-01-01

    Background Hepatitis B virus (HBV) infection is endemic in South Africa however, there is limited data on the degree of liver disease and geographic variation in HIV/HBV coinfected individuals. In this study, we analysed data from the CIPRA-SA ‘Safeguard the household study’ in order to assess baseline HBV characteristics in HIV/HBV co-infection participants prior to antiretroviral therapy (ART) initiation. Methods 812 participants from two South African townships Soweto and Masiphumelele were enrolled in a randomized trial of ART (CIPRA-SA). Participants were tested for hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), and HBV DNA. FIB-4 scores were calculated at baseline. Results Forty-eight (5.9%) were HBsAg positive, of whom 28 (58.3%) were HBeAg positive. Of those with HBV, 29.8% had an HBV DNA<2000 IU/ml and ALT<40 IU/ml ; 83.0% had a FIB-4 score <1.45, consistent with absent or minimal liver disease. HBV prevalence was 8.5% in Masiphumelele compared to 3.8% in Soweto (relative risk 2.3; 95% CI: 1.3–4.0). More participants in Masiphumelele had HBeAg-negative disease (58% vs. 12%, p = 0.002) and HBV DNA levels ≤2000 IU/ml, (43% vs. 6% p<0.007). Conclusion One third of HIV/HBV co-infected subjects had low HBV DNA levels and ALT while the majority had indicators of only mild liver disease. There were substantial regional differences in HBsAg and HbeAg prevalence in HIV/HBV co-infection between two regions in South Africa. This study highlights the absence of severe liver disease and the marked regional differences in HIV/HBV co-infection in South Africa and will inform treatment decisions in these populations. PMID:24324573

  16. [Hand injuries caused by snake bites. Apropos of 9 cases treated in a West African regional hospital].

    PubMed

    Ribault, L

    1990-01-01

    The author reports 9 cases of snake bite hand injuries in a regional hospital in the ivory coast. This study presents a number of particular points: patients often consult quite late; the precarious hygiene induces microbia contamination; patients often have a very poor conception of their body schema, which sometimes creates problems of understanding during reeducation. Treatment consists of emergency debridement under antibiotic cover of Iselin's "emergency with delayed surgery". The good blood supply of the hand allows satisfactory functional results. PMID:1712571

  17. Nonlinear responses of southern African rainfall to forcing from Atlantic SST in a high-resolution regional climate model

    NASA Astrophysics Data System (ADS)

    Williams, C.; Kniveton, D.; Layberry, R.

    2009-04-01

    It is increasingly accepted that any possible climate change will not only have an influence on mean climate but may also significantly alter climatic variability. A change in the distribution and magnitude of extreme rainfall events (associated with changing variability), such as droughts or flooding, may have a far greater impact on human and natural systems than a changing mean. This issue is of particular importance for environmentally vulnerable regions such as southern Africa. The subcontinent is considered especially vulnerable to and ill-equipped (in terms of adaptation) for extreme events, due to a number of factors including extensive poverty, famine, disease and political instability. Rainfall variability is a function of scale, so high spatial and temporal resolution data are preferred to identify extreme events and accurately predict future variability. In this research, high resolution satellite derived rainfall data from the Microwave Infra-Red Algorithm (MIRA) are used as a basis for undertaking model experiments using a state-of-the-art regional climate model. The MIRA dataset covers the period from 1993-2002 and the whole of southern Africa at a spatial resolution of 0.1 degree longitude/latitude. Once the model's ability to reproduce extremes has been assessed, idealised regions of sea surface temperature (SST) anomalies are used to force the model, with the overall aim of investigating the ways in which SST anomalies influence rainfall extremes over southern Africa. In this paper, results from sensitivity testing of the regional climate model's domain size are briefly presented, before a comparison of simulated daily rainfall from the model with the satellite-derived dataset. Secondly, simulations of current climate and rainfall extremes from the model are compared to the MIRA dataset at daily timescales. Finally, the results from the idealised SST experiments are presented, suggesting highly nonlinear associations between rainfall extremes

  18. Larger genetic differences within africans than between Africans and Eurasians.

    PubMed Central

    Yu, Ning; Chen, Feng-Chi; Ota, Satoshi; Jorde, Lynn B; Pamilo, Pekka; Patthy, Laszlo; Ramsay, Michele; Jenkins, Trefor; Shyue, Song-Kun; Li, Wen-Hsiung

    2002-01-01

    The worldwide pattern of single nucleotide polymorphism (SNP) variation is of great interest to human geneticists, population geneticists, and evolutionists, but remains incompletely understood. We studied the pattern in noncoding regions, because they are less affected by natural selection than are coding regions. Thus, it can reflect better the history of human evolution and can serve as a baseline for understanding the maintenance of SNPs in human populations. We sequenced 50 noncoding DNA segments each approximately 500 bp long in 10 Africans, 10 Europeans, and 10 Asians. An analysis of the data suggests that the sampling scheme is adequate for our purpose. The average nucleotide diversity (pi) for the 50 segments is only 0.061% +/- 0.010% among Asians and 0.064% +/- 0.011% among Europeans but almost twice as high (0.115% +/- 0.016%) among Africans. The African diversity estimate is even higher than that between Africans and Eurasians (0.096% +/- 0.012%). From available data for noncoding autosomal regions (total length = 47,038 bp) and X-linked regions (47,421 bp), we estimated the pi-values for autosomal regions to be 0.105, 0.070, 0.069, and 0.097% for Africans, Asians, Europeans, and between Africans and Eurasians, and the corresponding values for X-linked regions to be 0.088, 0.042, 0.053, and 0.082%. Thus, Africans differ from one another slightly more than from Eurasians, and the genetic diversity in Eurasians is largely a subset of that in Africans, supporting the out of Africa model of human evolution. Clearly, one must specify the geographic origins of the individuals sampled when studying pi or SNP density. PMID:12019240

  19. Tropical convective systems life cycle characteristics from geostationary satellite and precipitating estimates derived from TRMM and ground weather radar observations for the West African and South American regions

    NASA Astrophysics Data System (ADS)

    Fiolleau, T.; Roca, R.; Angelis, F. C.; Viltard, N.

    2012-12-01

    In the tropics most of the rainfall comes in the form of individual storm events embedded in the synoptic circulations (e.g., monsoons). Understanding the rainfall and its variability hence requires to document these highly contributing tropical convective systems (MCS). Our knowledge of the MCS life cycle, from a physical point of view mainly arises from individual observational campaigns heavily based on ground radar observations. While this large part of observations enabled the creation of conceptual models of MCS life cycle, it nevertheless does not reach any statistically significant integrated perspective yet. To overcome this limitation, a composite technique, that will serve as a Day-1 algorithm for the Megha-Tropiques mission, is considered in this study. this method is based on a collocation in space and time of the level-2 rainfall estimates (BRAIN) derived from the TMI radiometer onboard TRMM with the cloud systems identified by a new MCS tracking algorithm called TOOCAN and based on a 3-dimensional segmentation (image + time) of the geostationary IR imagery. To complete this study, a similar method is also developed collocating the cloud systems with the precipitating features derived from the ground weather radar which has been deployed during the CHUVA campaign over several Brazilian regions from 2010 up to now. A comparison of the MCSs life cycle is then performed for the 2010-2012 summer seasons over the West African, and South American regions. On the whole region of study, the results show that the temporal evolution of the cold cloud shield associated to MCSs describes a symmetry between the growth and the decay phases. It is also shown that the parameters of the conceptual model of MCSs are strongly correlated, reducing thereby the problem to a single degree of freedom. At the system scale, over both land and oceanic regions, rainfall is described by an increase at the beginning (the first third) of the life cycle and then smoothly decreases

  20. Seismic Anisotropy of the Lithosphere/Asthenosphere System Beneath the Rwenzori Region of the East-African Rift

    NASA Astrophysics Data System (ADS)

    Homuth, B.; Löbl, U.; Batte, A.; Link, K.; Kasereka, C.; Rumpker, G.

    2014-12-01

    We present results from a temporary seismic network of 32 broad-band stations located around the Rwenzori region of the Albertine rift at the border between Uganda and DR Congo. The study aims to constrain seismic anisotropy and mantle deformation processes in relation to the formation of the rift zone. Shear-wave splitting measurements from local and teleseismic earthquakes are used to investigate the seismic anisotropy in the crust and upper mantle beneath the Rwenzori region. At most stations, shear-wave splitting parameters obtained from individual earthquakes exhibit only minor variations with backazimuth. We therefore employ a joint inversion of SKS waveforms to derive hypothetical one-layer parameters. The corresponding fast polarizations are generally rift-parallel and the average delay time is about 1 s. On the other hand, shear phases from local events within the crust are characterized by an average delay time of 0.04 s. This observation suggests that the dominant source region for seismic anisotropy beneath the rift is located within the mantle. We use finite-frequency waveform modeling to test different models of anisotropy within the lithosphere/asthenosphere system of the rift. The results show that the rift-parallel fast polarizations are consistent with HTI anisotropy caused by magmatic intrusions or lenses located within the lithospheric mantle - as it would be expected during the early stages of continental rifting. Furthermore, the short-scale spatial variations in the fast polarizations observed in the southern part of the study area can be explained by effects due to sedimentary basins of low isotropic velocity in combination with a shift in the orientation of anisotropic fabrics in the upper mantle. A uniform anisotropic layer in relation to large-scale asthenospheric mantle flow is less consistent with the observed splitting parameters.

  1. Seismic anisotropy of the lithosphere/asthenosphere system beneath the Rwenzori region of the East-African Rift

    NASA Astrophysics Data System (ADS)

    Homuth, Benjamin; Löbl, Ulrike; Batte, Arthur; Link, Klemens; Kasereka, Celestine; Rümpker, Georg

    2014-05-01

    We present results from a temporary seismic network of 32 broad-band stations located around the Rwenzori region of the Albertine rift at the border between Uganda and DR Congo. The study aims to constrain seismic anisotropy and mantle deformation processes in relation to the formation of the rift zone. Shear-wave splitting measurements from local and teleseismic earthquakes are used to investigate the seismic anisotropy in the crust and upper mantle beneath the Rwenzori region. At most stations, shear-wave splitting parameters obtained from individual earthquakes exhibit only minor variations with backazimuth. We therefore employ a joint inversion of SKS waveforms to derive hypothetical one-layer parameters. The corresponding fast polarizations are generally rift-parallel and the average delay time is about 1 s. On the other hand, shear phases from local events within the crust are characterized by a bimodal pattern of fast polarizations and an average delay time of 0.04 s. This observation suggests that the dominant source region for seismic anisotropy beneath the rift is located within the mantle. We use finite-frequency waveform modeling to test different models of anisotropy within the lithosphere/asthenosphere system of the rift. The results show that the rift-parallel fast polarizations are consistent with HTI anisotropy caused by rift-parallel magmatic intrusions or lenses located within the lithospheric mantle - as it would be expected during the early stages of continental rifting. Furthermore, the short-scale spatial variations in the fast polarizations observed in the southern part of the study area can be explained by effects due to sedimentary basins of low isotropic velocity in combination with a shift in the orientation of anisotropic fabrics in the upper mantle. A uniform anisotropic layer in relation to large-scale asthenospheric mantle flow is less consistent with the observed splitting parameters.

  2. Regional assessment of lake ecological states using Landsat: A classification scheme for alkaline-saline, flamingo lakes in the East African Rift Valley

    NASA Astrophysics Data System (ADS)

    Tebbs, E. J.; Remedios, J. J.; Avery, S. T.; Rowland, C. S.; Harper, D. M.

    2015-08-01

    In situ reflectance measurements and Landsat satellite imagery were combined to develop an optical classification scheme for alkaline-saline lakes in the Eastern Rift Valley. The classification allows the ecological state and consequent value, in this case to Lesser Flamingos, to be determined using Landsat satellite imagery. Lesser Flamingos depend on a network of 15 alkaline-saline lakes in East African Rift Valley, where they feed by filtering cyanobacteria and benthic diatoms from the lakes' waters. The classification developed here was based on a decision tree which used the reflectance in Landsat ETM+ bands 2-4 to assign one of six classes: low phytoplankton biomass; suspended sediment-dominated; microphytobenthos; high cyanobacterial biomass; cyanobacterial scum and bleached cyanobacterial scum. The classification accuracy was 77% when verified against in situ measurements. Classified imagery and timeseries were produced for selected lakes, which show the different ecological behaviours of these complex systems. The results have highlighted the importance to flamingos of the food resources offered by the extremely remote Lake Logipi. This study has demonstrated the potential of high spatial resolution, low spectral resolution sensors for providing ecologically valuable information at a regional scale, for alkaline-saline lakes and similar hypereutrophic inland waters.

  3. Wild Termitomyces Species Collected from Ondo and Ekiti States Are More Related to African Species as Revealed by ITS Region of rDNA

    PubMed Central

    Oyetayo, Victor Olusegun

    2012-01-01

    Molecular identification of eighteen Termitomyces species collected from two states, Ondo and Ekiti in Nigeria was carried out using the internal transcribed spacer (ITS) region. The amplicons obtained from rDNA of Termitomyces species were compared with existing sequences in the NCBI GenBank. The results of the ITS sequence analysis discriminated between all the Termitomyces species (obtained from Ondo and Ekiti States) and Termitomyces sp. sequences obtained from NCBI GenBank. The degree of similarity of T1 to T18 to gene of Termitomyces sp. obtained from NCBI ranges between 82 and 99 percent. Termitomyces species from Garbon with ascension number AF321374 was the closest relative of T1 to T18 except T12 that has T. eurhizus and T. striatus as the closet relative. Phylogenetic tree generated with ITS sequences obtained from NCBI GenBank data revealed that T1 to T18 are more related to Termitomyces species indigenous to African countries such as Senegal, Congo, and Gabon. PMID:22649309

  4. Trend analysis of carbon monoxide distributions for changes in fire vs. anthropogenic sources in diverse African regions

    NASA Astrophysics Data System (ADS)

    Worden, H. M.; Worden, J. R.; Bloom, A. A.; Bowman, K. W.

    2015-12-01

    Satellite measurements of atmospheric carbon monoxide (CO) provide a signature for biomass burning and anthropogenic combustion-related pollution emissions. CO plays an important role in both air quality and climate as a precursor for tropospheric ozone and as a major sink of OH, the atmospheric "detergent" that affects the lifetime of methane and other pollutants. Worden et al., [2013] showed decreasing global CO values in time series of satellite total column CO measurements over the past decade. All of the satellite instruments that measure CO in the thermal infrared showed consistent inter-annual variability due to fires and possibly the global recession in late 2008. Observed decreases in CO over N. America and Europe were consistent with expected decreases in CO emissions inventories [Granier et al., 2011], however, the decrease is not uniform globally. In particular, Africa shows regions with smaller negative trends and potentially increasing trends in CO concentration. Here we examine trends for surface and total column CO concentrations in Africa over 2002-2014 using MOPITT V5J data. Our hypothesis is that temporal changes in CO will have different signatures related to anthropogenic and biomass burning emissions. We use singular value decomposition (SVD) with time series from different regions based on vegetation type and population density to diagnose the dominant trends and their potential drivers.

  5. Geochronology of the Birim Supergroup of the West African craton in the Wa-Bolé region of west-central Ghana: Implications for the stratigraphic framework

    NASA Astrophysics Data System (ADS)

    de Kock, G. S.; Armstrong, R. A.; Siegfried, H. P.; Thomas, E.

    2011-01-01

    The Birim rocks of the West African craton comprise belts of greenschist- to amphibolite-grade gneiss and schist, and subparallel basins of greenschist-grade phyllite of volcaniclastic and epiclastic origin, which were intruded by igneous rocks. The granitoids intruded between 2213 and 2060 Ma and overlap with the volcaniclastic units dated between 2211 and 2064 Ma. The simultaneous occurrence of the magmatic events and irregular distribution of the rock ages hamper the formulation of a stratigraphic succession. SHRIMP spot analyses were done on older cores, crystals and rims from 23 rocks from the Bolé-Wa region in west-central Ghana. The crystallization ages range from 2195 to 2118 Ma, the inherited ages from 2876 to 2130 Ma, and metamorphic ages from 2114 to 2090 Ma. Aided by metamorphic, structural and chemical studies an older geotectonic cycle (2195-2150 Ma), containing the Dole and Guropie Suite and Bolé Group, was established. These units were subjected to several orthogonal and shear deformation events. These events were followed by the contemporaneous Sawla calc-alkaline monzonitic plutonism (2132-2126 Ma) and deposition of the epiclastic Maluwe Group (2137-2125 Ma) of calc-alkaline felsic to tholeiitic volcanic origin. Deformation of the basin beds was succeeded by the intrusion of the Tanina Suite granitoids of 2122-2120 Ma, which, themselves, were deformed prior to 2119 Ma. At 2118 Ma syenite and gabbro intruded along conjugate extension fractures. The gabbro and syenite of the Wakawaka Suite were only affected by three events of brittle strike-slip faulting. The first had significant displacement along NNE- to NE-directed shear zones, while the latter only formed conjugate joint systems with limited transport. Palaeo- to Neoarchaean cores, the oldest yet reported in the Baoulé Mossi domain, are restricted to the gneissic Dole Suite biotite granites. The presence of Dole-, Guropie-, Sawla-, and Tanina-aged older cores and grains in younger rocks

  6. Association of polymorphisms at the ADIPOR1 regulatory region with type 2 diabetes and body mass index in a Brazilian population with European or African ancestry.

    PubMed

    Yeh, E; Kimura, L; Errera, F I V; Angeli, C B; Mingroni-Netto, R C; Silva, M E R; Canani, L H S; Passos-Bueno, M R

    2008-06-01

    Association studies between ADIPOR1 genetic variants and predisposition to type 2 diabetes (DM2) have provided contradictory results. We determined if two single nucleotide polymorphisms (SNP c.-8503G>A and SNP c.10225C>G) in regulatory regions of ADIPOR1 in 567 Brazilian individuals of European (EA; N = 443) or African (AfA; N = 124) ancestry from rural (quilombo remnants; N = 439) and urban (N = 567) areas. We detected a significant effect of ethnicity on the distribution of the allelic frequencies of both SNPs in these populations (EA: -8503A = 0.27; AfA: -8503A = 0.16; P = 0.001 and EA: 10225G = 0.35; AfA: 10225G = 0.51; P < 0.001). Neither of the polymorphisms were associated with DM2 in the case-control study in EA (SNP c.-8503G>A: DM2 group -8503A = 0.26; control group -8503A = 0.30; P = 0.14/SNP 10225C>G: DM2 group 10225G = 0.37; control group 10225G = 0.32; P = 0.40) and AfA populations (SNP c.-8503G>A: DM2 group -8503A = 0.16; control group -8503A = 0.15; P = 0.34/SNP 10225C>G: DM2 group 10225G = 0.51; control group 10225G = 0.52; P = 0.50). Similarly, none of the polymorphisms were associated with metabolic/anthropometric risk factors for DM2 in any of the three populations, except for HDL cholesterol, which was significantly higher in AfA heterozygotes (GC = 53.75 +/- 17.26 mg/dL) than in homozygotes. We conclude that ADIPOR1 polymorphisms are unlikely to be major risk factors for DM2 or for metabolic/anthropometric measurements that represent risk factors for DM2 in populations of European and African ancestries. PMID:18622492

  7. Multi-stage emerald formation during Pan-African regional metamorphism: The Zabara, Sikait, Umm Kabo deposits, South Eastern desert of Egypt

    NASA Astrophysics Data System (ADS)

    Grundmann, G.; Morteani, G.

    2008-02-01

    The genesis of gem-quality deep green emeralds of Zabara, Sikait and Umm Kabo (South Eastern Desert, Egypt) is to date a controversial topic. The emerald-bearing biotite schists and quartz lenses are interpreted alternatively as a product of (i) thrust-fault-shear zone - controlled large scale alkali-metasomatism driven by post-magmatic fluid flow or of (ii) a large scale interaction between syntectonic pegmatitic magma or hydrothermal fluids with pre-existing basic to ultrabasic rocks, or of (iii) a syn- to post-tectonic regional metamorphism and small scale blackwall metasomatism. Detailed microstructural and chemical analyses of the Egyptian emeralds and their host rocks show that three generations of beryl can be distinguished: a colourless pegmatitic beryl; a pale green Cr-poor beryl crystallized from pegmatite-related hydrothermal fluids; and a deep green Cr- and Mg-rich emerald. The crystallization of the Cr- and Mg-rich emerald was controlled by the very local availability of Cr, Mg and Be-rich metamorphic fluids during the Pan-African tectono-thermal event. Emerald-rich quartz lenses demonstrate that those fluids locally did mobilize quartz, too. The pale green emeralds found within the pegmatites in association with colourless beryl are the product of a mobilization of colourless pegmatitic beryl and/or phenakite by late pegmatitic fluids slightly enriched in Cr by an interaction with the Cr-rich country rocks. The late pegmatitic fluids are typically Na-rich as is demonstrated by the pervasive albitization of the pegmatites. The complex interplay of magmatic and regional metamorphic events during the genesis of the Egyptian emeralds/beryls makes it impossible through stable oxygen isotope data to relate their genesis to the one or the other event.

  8. Tyrosinase-positive oculocutaneous albinism in Southern African blacks: P gene-associated haplotypes suggest a major mutation in the 5{prime} region of the gene

    SciTech Connect

    Ramsay, M.; Stevens, G.; Beukering, J. van

    1994-09-01

    Tyrosinase-positive oculocutaneous albinism (ty-pos OCA) occurs with a prevalence of 1 in 3900 among Southern African (SA) blacks. The major contributors to morbidity and mortality are skin cancer and decreased visual acuity. Two distinct phenotypes occur, namely individuals with ephelides (darkly pigmented patches) and those without. There is complete concordance with regard to ephelus status among siblings. The disorder is linked to markers on chromosome 15q11.2-q12, and no obligatory cross-overs were observed with polymophic markers at the human homolog, P, of the mouse pink eyed dilute gene, p. Contrary to what has been shown for Caucasoid ty-pos OCA, this condition shows locus homogeneity among SA blacks. The P gene is an excellent candidate for ty-pos OCA and mutations in this gene will confirm its role in causing the common form of albinism in SA. Numerous P gene mutations have been described in other populations. In an attempt to detect mutations, the P gene cDNA was used to search for structural rearrangements or polymorphisms. Six polymorphisms (plR10/Scal, 912/Xbal, 912/HincII, 912/TaqI, 1412/TaqI [two systems] and 1412/HindIII) were detected with subclones of the P cDNA and haplotypes were determined in each family. None were clearly associated with an albinism-related rearrangement. However, strong linkage disequilibrium was observed with alleles at loci toward the 5{prime} region of the gene ({triangle}=0.65, 0.57 and 0.80 for the three polymorphisms detected with the 912 subclone), suggesting a major ty-pos OCA mutation in this region. Haplotype analysis provides evidence for a major mutation associated with the same haplotype in individuals with ephelides (8/12 OCA chromosomes) and those without ephelides (24:30). The presence of other ty-pos OCA associated haplotypes indicates several other less common mutations.

  9. Current status and future prospects of epidemiology and public health training and research in the WHO African region

    PubMed Central

    Nachega, Jean B; Uthman, Olalekan A; Ho, Yuh-Shan; Lo, Melanie; Anude, Chuka; Kayembe, Patrick; Wabwire-Mangen, Fred; Gomo, Exnevia; Sow, Papa Salif; Obike, Ude; Kusiaku, Theophile; Mills, Edward J; Mayosi, Bongani M; IJsselmuiden, Carel

    2012-01-01

    Background To date little has been published about epidemiology and public health capacity (training, research, funding, human resources) in WHO/AFRO to help guide future planning by various stakeholders. Methods A bibliometric analysis was performed to identify published epidemiological research. Information about epidemiology and public health training, current research and challenges was collected from key informants using a standardized questionnaire. Results From 1991 to 2010, epidemiology and public health research output in the WHO/AFRO region increased from 172 to 1086 peer-reviewed articles per annum [annual percentage change (APC) = 10.1%, P for trend < 0.001]. The most common topics were HIV/AIDS (11.3%), malaria (8.6%) and tuberculosis (7.1%). Similarly, numbers of first authors (APC = 7.3%, P for trend < 0.001), corresponding authors (APC = 8.4%, P for trend < 0.001) and last authors (APC = 8.5%, P for trend < 0.001) from Africa increased during the same period. However, an overwhelming majority of respondents (>90%) reported that this increase is only rarely linked to regional post-graduate training programmes in epidemiology. South Africa leads in publications (1978/8835, 22.4%), followed by Kenya (851/8835, 9.6%), Nigeria (758/8835, 8.6%), Tanzania (549/8835, 6.2%) and Uganda (428/8835, 4.8%) (P < 0.001, each vs South Africa). Independent predictors of relevant research productivity were ‘in-country numbers of epidemiology or public health programmes’ [incidence rate ratio (IRR) = 3.41; 95% confidence interval (CI) 1.90–6.11; P = 0.03] and ‘number of HIV/AIDS patients’ (IRR = 1.30; 95% CI 1.02–1.66; P < 0.001). Conclusions Since 1991, there has been increasing epidemiological research productivity in WHO/AFRO that is associated with the number of epidemiology programmes and burden of HIV/AIDS cases. More capacity building and training initiatives in epidemiology are required to promote research and address the public health challenges

  10. African-American Student Achievement Research Project.

    ERIC Educational Resources Information Center

    Wagstaff, Mark; Melton, Jerry; Lawless, Brenda; Combs, Linda

    Data from the Texas Assessment of Academic Skills (TAAS) reveal that gains in performance for the African American student population of Region VII of the state's educational system were not keeping pace with the performance of African Americans in the rest of Texas. This study investigated practices in school districts in the region in which…

  11. Possible Climate Change/Variability and Human Impacts, Vulnerability of African Drought Prone Regions, its Water Resources and Capacity Building

    NASA Astrophysics Data System (ADS)

    Yew Gan, Thian; Huelsmann, Stephen; Qin, XiaoSheng; Lu, Xi Xi; Liong, Shie-Yui; Rutschmann, Peter; Disse, Markus; Koivusalo, Harri

    2016-04-01

    The climate, water resources and historical droughts of Africa, drought indices, vulnerability, impact of global warming and landuse to drought-prone regions in West, Southern, and Greater Horn of Africa, which have suffered recurrent severe droughts in the past are reviewed first. Recent studies detected warming and drying trends in Africa since the mid-20th century. Based on the 4th Assessment Report of the Intergovernmental Panel of Climate Change, and that of the 5th Coupled Model Intercomparison Project (CMIP5), both northern and southern Africa are projected to experience drying such as decreasing precipitation, runoff and soil moisture in the 21st Century and could become more vulnerable to impact of droughts. The daily maximum temperature is projected to increase up to 8oC (RCP8.5 of CMIP5), precipitation indices such as total wet day precipitation (PRCPTOT) and heavy precipitation days (R10mm) could decrease, while warm spell duration (WSDI) and consecutive dry days (CDD) could increase. Uncertainties of the above long-term projections, teleconnections to climate anomalies such as ENSO and Madden Julian Oscillation which could also affect water resources of Africa, and capacity building in terms of physical infrastructure and non-structural solutions, are also discussed. Given traditional climate and hydrologic data observed in Africa are generally limited, satellite data should also be exploited to fill in the data gap for Africa in future.

  12. Ionospheric F region effects observed in the American and African sectors during the intense geomagnetic storm of September-October 2012

    NASA Astrophysics Data System (ADS)

    De Jesus, Rodolfo; Gende, Mauricio; Fagundes, Paulo Roberto; Coster, Anthea; Bolaji, Segun; Kavutarapu, Venkatesh; De Abreu, Alessandro; Sobral, J. H. A.; Pillat, Valdir Gil; Batista, Inez S.

    This study presents an investigation of geomagnetic disturbance effects on the equatorial, low- and mid-latitude ionospheric F region over the American and African sectors during the intense geomagnetic storm (maximum Kp index of 6.7) that occurred on 30th September, 2012 and 1st October, 2012. In this study digital ionosonde and Global Positioning System (GPS) data are simultaneously utilized from 30th September to 3rd October 2012. The diurnal variability over this four day period observed from both the digital ionosonde and from ground based GPS units can be characterized as quiet, slightly disturbed, and strongly disturbed periods. This time period includes the sudden commencement of the storm (SCS), the main phase (MPS), and the recovery phase of the storm (RPS). During the period of investigation, ionospheric parameters F-region critical frequency (foF2) and minimum F-region virtual height ('hF) were obtained at Jicamarca, São Luís, Fortaleza, Palmas and Port Stanley at the following geographical coordinates, respectively: 12.0ºS 76.8ºW, 2.6ºS 44.2ºW, 3.8ºS 38ºW, 10.2ºS 48.8ºW and 51.6ºS 57.9ºW. In this study, we also used observations of 20 GPS stations located at Greenbelt (39.0ºN, 76.8ºW), Cambridge (38.6ºN, 76.1ºW), Virgin Islands (17.6ºN, 64.6ºW), Eusebio (03.9ºS, 38.4ºW), Iquitos (03.8ºS, 73.3 ºW), Arequipa (16.5ºS, 71.5ºW), Cachoeira Paulista (22.7ºS, 45.0ºW), Copiapo (27.4ºS, 70.4ºW), La Plata (34.9ºS, 57.9ºW), Concepcion (36.8ºS, 73.0ºW), Rio Grande (53.8ºS, 67.8ºW), Dakar (14.7ºN, 17.4ºW), Addis (09.0ºN, 38.8ºE), Cotonou (06.4ºN, 02.5ºE), Libreville (00.4ºN, 09.7ºE), Mbarara (00.6ºS, 30.7ºE), Lusaka (15.4ºS, 28.3ºE), Windhoek (22.6ºS, 17.1ºE), Springbok (29.7ºS, 17.9ºE) and Sutherland (32.4ºS, 20.8ºE). Vertical Total Electron Content (VTEC) and TEC fluctuations (ROT, rate of change of TEC) are calculated from GPS data using the measured Slant Total Electron Content (STEC) records from the 20 GPS

  13. Mitigation of Disasters Due to Severe Climate Events: from Policy to Practice,the West African Coastal Region Experience

    NASA Astrophysics Data System (ADS)

    Ediang, Okuku

    2016-07-01

    The distributive pattern of disaster due to severe climate events over the coast of West Africa especially Nigeria was examined using yearly mean disaster due to severe climatic events for the period of 30 years (1981-2010) from the marine stations in the coastal region of Nigeria. Graphical and isohyetal analyses were used to look into the patter of severe weather events over the area considered and to see if the severe weather events is increasing or not in the coast of West Africa especially the Nigerian coast and how to mitigate ,were policy relating to severe weather events are discussed. The paper conclude that due to the nature of coast of West Africa and Nigeria in particular, it enjoys longer severe weather events season than dry during the wet season, it is common to observe periods of enhanced or suppressed convective activity to persist over the wide areas for somedays. This paper also contributes to the wealth of knowledge already existing on Indigenous people play major roles in preserving the ecosystem especially during severe weather events . This has resulted in the recent calls for the integration of indigenous knowledge systems into global knowledge system strategies. Until now, integrating local knowledge systems into severe weather events and climate change concerns is not a completely new idea. A comprehensive review of literature using electronic and non-electronic databases formed the methodology. The paper conclude also by drawing the attention that by targeting Promoting indigenous people's participation in severe weather events and climate change issues is an important initiative towards adaptation and sustainable development in Africa and around the world. It is increasingly realized that the global knowledge system has dominated research, policies and programmes that address current severe weather events and climate change's challenges,mitigation and adaptation strategies.

  14. How Rainfall Variation Influences Reproductive Patterns of African Savanna Ungulates in an Equatorial Region Where Photoperiod Variation Is Absent.

    PubMed

    Ogutu, Joseph O; Owen-Smith, Norman; Piepho, Hans-Peter; Dublin, Holly T

    2015-01-01

    In high temperate latitudes, ungulates generally give birth within a narrow time window when conditions are optimal for offspring survival in spring or early summer, and use changing photoperiod to time conceptions so as to anticipate these conditions. However, in low tropical latitudes day length variation is minimal, and rainfall variation makes the seasonal cycle less predictable. Nevertheless, several ungulate species retain narrow birth peaks under such conditions, while others show births spread quite widely through the year. We investigated how within-year and between-year variation in rainfall influenced the reproductive timing of four ungulate species showing these contrasting patterns in the Masai Mara region of Kenya. All four species exhibited birth peaks during the putative optimal period in the early wet season. For hartebeest and impala, the birth peak was diffuse and offspring were born throughout the year. In contrast, topi and warthog showed a narrow seasonal concentration of births, with conceptions suppressed once monthly rainfall fell below a threshold level. High rainfall in the previous season and high early rains in the current year enhanced survival into the juvenile stage for all the species except impala. Our findings reveal how rainfall variation affecting grass growth and hence herbivore nutrition can govern the reproductive phenology of ungulates in tropical latitudes where day length variation is minimal. The underlying mechanism seems to be the suppression of conceptions once nutritional gains become insufficient. Through responding proximally to within-year variation in rainfall, tropical savanna ungulates are less likely to be affected adversely by the consequences of global warming for vegetation phenology than northern ungulates showing more rigid photoperiodic control over reproductive timing. PMID:26295154

  15. How Rainfall Variation Influences Reproductive Patterns of African Savanna Ungulates in an Equatorial Region Where Photoperiod Variation Is Absent

    PubMed Central

    Ogutu, Joseph O.; Owen-Smith, Norman; Piepho, Hans-Peter; Dublin, Holly T.

    2015-01-01

    In high temperate latitudes, ungulates generally give birth within a narrow time window when conditions are optimal for offspring survival in spring or early summer, and use changing photoperiod to time conceptions so as to anticipate these conditions. However, in low tropical latitudes day length variation is minimal, and rainfall variation makes the seasonal cycle less predictable. Nevertheless, several ungulate species retain narrow birth peaks under such conditions, while others show births spread quite widely through the year. We investigated how within-year and between-year variation in rainfall influenced the reproductive timing of four ungulate species showing these contrasting patterns in the Masai Mara region of Kenya. All four species exhibited birth peaks during the putative optimal period in the early wet season. For hartebeest and impala, the birth peak was diffuse and offspring were born throughout the year. In contrast, topi and warthog showed a narrow seasonal concentration of births, with conceptions suppressed once monthly rainfall fell below a threshold level. High rainfall in the previous season and high early rains in the current year enhanced survival into the juvenile stage for all the species except impala. Our findings reveal how rainfall variation affecting grass growth and hence herbivore nutrition can govern the reproductive phenology of ungulates in tropical latitudes where day length variation is minimal. The underlying mechanism seems to be the suppression of conceptions once nutritional gains become insufficient. Through responding proximally to within-year variation in rainfall, tropical savanna ungulates are less likely to be affected adversely by the consequences of global warming for vegetation phenology than northern ungulates showing more rigid photoperiodic control over reproductive timing. PMID:26295154

  16. African Aesthetics

    ERIC Educational Resources Information Center

    Abiodun, Rowland

    2001-01-01

    No single traditional discipline can adequately supply answers to the many unresolved questions in African art history. Because of the aesthetic, cultural, historical, and, not infrequently, political biases, already built into the conception and development of Western art history, the discipline of art history as defined and practiced in the West…

  17. Gas isotopic signatures (He, C, and Ar) in the Lake Kivu region (western branch of the East African rift system): Geodynamic and volcanological implications

    NASA Astrophysics Data System (ADS)

    Tedesco, D.; Tassi, F.; Vaselli, O.; Poreda, R. J.; Darrah, T.; Cuoco, E.; Yalire, M. M.

    2010-01-01

    On 17 January 2002, the city of Goma was partly destroyed by two of the several lava flows erupted from a roughly N-S oriented fracture system opened along the southern flank of Mount Nyiragongo (Democratic Republic of Congo), in the western branch of the East African rift system. A humanitarian and scientific response was promptly organized by international, governmental, and nongovernmental agencies coordinated by the United Nations and the European Union. Among the different scientific projects undertaken to study the mechanisms triggering this and possible future eruptions, we focused on the isotopic (He, C, and Ar) analysis of the magmatic-hydrothermal and cold gas discharges related to the Nyiragongo volcanic system, the Kivu and Virunga region. The studied area includes the Nyiragongo volcano, its surroundings, and peripheral areas inside and outside the rift. They have been subdivided into seven regions characterized by distinct 3He/4He (expressed as R/Rair) ratios and/or δ13C-CO2 values. The Nyiragongo summit crater fumaroles, whose R/Rair and δ13C-CO2 values are up to 8.73 and from -3.5‰ to -4.0‰ VPDB, respectively, show a clear mantle, mid-ocean ridge basalt (MORB)-like contribution. Similar mantle-like He isotopic values (6.5-8.3 R/Rair) are also found in CO2-rich gas emanations (mazukus) along the northern shoreline of Lake Kivu main basin, whereas the 13δC-CO2 values range from -5.3‰ to -6.8‰ VPDB. The mantle influence progressively decreases in (1) dissolved gases of Lake Kivu (2.6-5.5 R/Rair) and (2) the distal gas discharges within and outside the two sides of the rift (from 0.1 to 1.7 R/Rair). Similarly, δ13C-CO2 ratios of the peripheral gas emissions are lighter (from -5.9‰ to -11.6‰ VPDB) than those of the crater fumaroles. Therefore, the spatial distribution of He and C signatures in the Lake Kivu region is mainly produced by mixing of mantle-related (e.g., Nyiragongo crater fumaroles and/or mazukus gases) and crustal-related (e

  18. Understanding the Environmental and Climate Impacts of Biomass Burning in Northern Sub-Saharan Africa

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles; Gatebe, Charles; Bolten, John; Policelli, Fritz; Habib, Shahid; Lee, Jejung; Wang, Jun; Wilcox, Eric; Adegoke, Jimmy

    2011-01-01

    The northern sub-Saharan African (NSSA) region, bounded on the north and south by the Sahara and the Equator, respectively, and stretching from the West to the East African coastlines, has one of the highest biomass-burning rates per unit land area among all regions of the world. Because of the high concentration and frequency of fires in this region, with the associated abundance of heat release and gaseous and particulate smoke emissions, biomass-burning activity is believed to be one of the drivers of the regional carbon and energy cycles, with serious implications for the water cycle. A new interdisciplinary research effort sponsored by NASA is presently being focused on the NSSA region, to better understand the possible connection between the intense biomass burning observed from satellite year after year across the region and the rapid depletion of the regional water resources, as exemplified by the dramatic drying of Lake Chad. A combination of remote sensing and modeling approaches is being utilized in investigating multiple regional surface, atmospheric, and water-cycle processes, and inferring possible links between them. In this presentation, we will discuss preliminary results as well as the path toward improved understanding'of the interrelationships and feedbacks between the biomass burning and the environmental change dynamics in the NSSA region.

  19. Genome-wide patterns of population structure and admixture in West Africans and African Americans.

    PubMed

    Bryc, Katarzyna; Auton, Adam; Nelson, Matthew R; Oksenberg, Jorge R; Hauser, Stephen L; Williams, Scott; Froment, Alain; Bodo, Jean-Marie; Wambebe, Charles; Tishkoff, Sarah A; Bustamante, Carlos D

    2010-01-12

    Quantifying patterns of population structure in Africans and African Americans illuminates the history of human populations and is critical for undertaking medical genomic studies on a global scale. To obtain a fine-scale genome-wide perspective of ancestry, we analyze Affymetrix GeneChip 500K genotype data from African Americans (n = 365) and individuals with ancestry from West Africa (n = 203 from 12 populations) and Europe (n = 400 from 42 countries). We find that population structure within the West African sample reflects primarily language and secondarily geographical distance, echoing the Bantu expansion. Among African Americans, analysis of genomic admixture by a principal component-based approach indicates that the median proportion of European ancestry is 18.5% (25th-75th percentiles: 11.6-27.7%), with very large variation among individuals. In the African-American sample as a whole, few autosomal regions showed exceptionally high or low mean African ancestry, but the X chromosome showed elevated levels of African ancestry, consistent with a sex-biased pattern of gene flow with an excess of European male and African female ancestry. We also find that genomic profiles of individual African Americans afford personalized ancestry reconstructions differentiating ancient vs. recent European and African ancestry. Finally, patterns of genetic similarity among inferred African segments of African-American genomes and genomes of contemporary African populations included in this study suggest African ancestry is most similar to non-Bantu Niger-Kordofanian-speaking populations, consistent with historical documents of the African Diaspora and trans-Atlantic slave trade. PMID:20080753

  20. Effects of the intense geomagnetic storm of September-October 2012 on the equatorial, low- and mid-latitude F region in the American and African sector during the unusual 24th solar cycle

    NASA Astrophysics Data System (ADS)

    de Jesus, R.; Fagundes, P. R.; Coster, A.; Bolaji, O. S.; Sobral, J. H. A.; Batista, I. S.; de Abreu, A. J.; Venkatesh, K.; Gende, M.; Abalde, J. R.; Sumod, S. G.

    2016-02-01

    The main purpose of this paper is to investigate the response of the ionospheric F layer in the American and African sectors during the intense geomagnetic storm which occurred on 30 September-01 October 2012. In this work, we used observations from a chain of 20 GPS stations in the equatorial, low- and mid-latitude regions in the American and African sectors. Also, in this study ionospheric sounding data obtained during 29th September to 2nd October, 2012 at Jicamarca (JIC), Peru, São Luis (SL), Fortaleza (FZ), Brazil, and Port Stanley (PST), are presented. On the night of 30 September-01 October, in the main and recovery phase, the h´F variations showed an unusual uplifting of the F region at equatorial (JIC, SL and FZ) and mid- (PST) latitude stations related with the propagations of traveling ionospheric disturbances (TIDs) generated by Joule heating at auroral regions. On 30 September, the VTEC variations and foF2 observations at mid-latitude stations (American sector) showed a long-duration positive ionospheric storm (over 6 h of enhancement) associated with large-scale wind circulations and equatorward neutral winds. Also, on 01 October, a long-duration positive ionospheric storm was observed at equatorial, low- and mid- latitude stations in the African sector, related with the large-scale wind circulations and equatorward neutral winds. On 01 and 02 October, positive ionospheric storms were observed at equatorial, low- and mid-latitude stations in the American sector, possibly associated with the TIDs and an equatorward neutral wind. Also, on 01 October negative ionospheric storms were observed at equatorial, low- and mid-latitude regions in the American sector, probably associated with the changes in the O/N2 ratio. On the night of 30 September-01 October, ionospheric plasma bubbles were observed at equatorial, low- and mid- latitude stations in the South American sector, possibly associated with the occurrence of geomagnetic storm.

  1. African horse sickness.

    PubMed

    Zientara, S; Weyer, C T; Lecollinet, S

    2015-08-01

    African horse sickness (AHS) is a devastating disease of equids caused by an arthropod-borne virus belonging to the Reoviridae family, genus Orbivirus. It is considered a major health threat for horses in endemic areas in sub-Saharan Africa. African horse sickness virus (AHSV) repeatedly caused large epizootics in the Mediterranean region (North Africa and southern Europe in particular) as a result of trade in infected equids. The unexpected emergence of a closely related virus, the bluetongue virus, in northern Europe in 2006 has raised fears about AHSV introduction into Europe, and more specifically into AHSV-free regions that have reported the presence of AHSV vectors, e.g. Culicoides midges. North African and European countries should be prepared to face AHSV incursions in the future, especially since two AHSV serotypes (serotypes 2 and 7) have recently spread northwards to western (e.g. Senegal, Nigeria, Gambia) and eastern Africa (Ethiopia), where historically only serotype 9 had been isolated. The authors review key elements of AHS epidemiology, surveillance and prophylaxis. PMID:26601437

  2. Spatio-temporal characteristics of the Equatorial Ionization Anomaly (EIA) in the East African region via ionospheric tomography during the year 2012

    NASA Astrophysics Data System (ADS)

    Kassa, T.; Damtie, B.; Bires, A.; Yizengaw, E.; Cilliers, P.

    2015-01-01

    We present the characteristics of the EIA in the East African sector inferred from ground-based GPS receivers via ionospheric tomography during the year 2012. For the analysis, we developed and used a 2D ionospheric tomography imaging software based on Bayesian inversion approach. To reconstruct ionospheric electron density form slant Total Electron Content (sTEC) measurements, we selected a chain of ten ground-based GPS receivers with stations' codes and geomagnetic coordinates: ARMI (3.03 °S, 109.29 °E), DEBK (4.32 °N, 109.48 °E), ASOS (1.14 °N, 106.16 °E), NEGE (3.60 °S, 111.35 °E), SHIS (3.26 °N, 110.62 °E), ASAB (4.91 °N, 114.34 °E), SHEB (7.36 °N, 110.60 °E), EBBE (9.54 °S, 104.10 °E), DODM (16.03 °S, 109.04 °E) & NAMA (11.49 °N, 113.60 °E). The temporal, spatial and storm-time characteristics of the EIA and the hourly, day-to-day and seasonal variations of the maximum electron density of F2 region (NmF2) at 15.29°S geomagnetic latitude are presented. We found that the magnitude of the peak and the width/thickness of the EIA pronounced during the equinox and weakened during the solstice seasons at 2100 LT. It is also observed that the EIA persisted for longer time in equinox season than the solstice season. The spatial appearance of the northern and southern anomalies are observed starting from 6.12 ° N and 10 ° S respectively along geomagnetic latitude during equinox season. The EIA is localized between 180 km and 450 km along the altitude during December solstice. The analysis on the NmF2 demonstrated a significant dependence on local time, day and season of the year. We also investigated the storm response of the EIA for the magnetic storm of Day Of the Year (DOY) 274-276. It is observed that the disturbance dynamo related composition change (O/N2 ratio) resulted in a well-developed EIA with an increase in the peak and the width of the EIA at 2100 LT on DOY 275 (main phase of the storm) compared to 274 (initial phase of the storm

  3. An Analysis of Children's Drawings of What They Think Is inside Their Bodies: A South African Regional Study

    ERIC Educational Resources Information Center

    Dempster, Edith; Stears, Michèle

    2014-01-01

    The purpose of the study is to find out what a group of seven-year-old South African children understand of their internal anatomy. The research is based on the premise that young children obtain most of their science knowledge through personal experience. Drawings are used to determine the level of young children's knowledge of systems and…

  4. Technical Education and Vocational Training in Central Africa. Feasibility Survey of the Regional Development of Rapid Vocational Training: Cameroon, Central African Republic, Chad, and Gabon.

    ERIC Educational Resources Information Center

    Organization for Rehabilitation through Training, Geneva (Switzerland).

    This final report is the result of a survey requested by the United States Agency for International Development (USAID) and undertaken by the Organization for Rehabilitation through Training (ORT) of four countries (Cameroon, Chad, Central African Republic, and Gabon) and a conference on vocational training sponsored by the Economic and Customs…

  5. 9 CFR 94.8 - Pork and pork products from regions where African swine fever exists or is reasonably believed to...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ....) and regulations thereunder (9 CFR, chapter III, part 327), including requirements that the pork or...) Editorial Note: For Federal Register citations affecting § 94.8, see the List of CFR Sections Affected... where African swine fever exists or is reasonably believed to exist. 94.8 Section 94.8 Animals...

  6. 9 CFR 94.8 - Pork and pork products from regions where African swine fever exists or is reasonably believed to...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ....) and regulations thereunder (9 CFR, chapter III, part 327), including requirements that the pork or...) Editorial Note: For Federal Register citations affecting § 94.8, see the List of CFR Sections Affected... where African swine fever exists or is reasonably believed to exist. 94.8 Section 94.8 Animals...

  7. 9 CFR 94.8 - Pork and pork products from regions where African swine fever exists or is reasonably believed to...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ....C. 601 et seq.) and regulations thereunder (9 CFR, chapter III, part 327), including requirements... number 0579-0015) Editorial Note: For Federal Register citations affecting § 94.8, see the List of CFR... where African swine fever exists or is reasonably believed to exist. 94.8 Section 94.8 Animals...

  8. 9 CFR 94.8 - Pork and pork products from regions where African swine fever exists or is reasonably believed to...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ....) and regulations thereunder (9 CFR, chapter III, part 327), including requirements that the pork or...) Editorial Note: For Federal Register citations affecting § 94.8, see the List of CFR Sections Affected... where African swine fever exists or is reasonably believed to exist. 94.8 Section 94.8 Animals...

  9. 9 CFR 94.8 - Pork and pork products from regions where African swine fever exists or is reasonably believed to...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ....) and regulations thereunder (9 CFR, chapter III, part 327), including requirements that the pork or...) Editorial Note: For Federal Register citations affecting § 94.8, see the List of CFR Sections Affected... where African swine fever exists or is reasonably believed to exist. 94.8 Section 94.8 Animals...

  10. Obesity and African Americans

    MedlinePlus

    ... Data > Minority Population Profiles > Black/African American > Obesity Obesity and African Americans African American women have the ... ss6304.pdf [PDF | 3.38MB] HEALTH IMPACT OF OBESITY More than 80 percent of people with type ...

  11. Structural analysis of the 5 prime flanking region of the. beta. -globin gene in African sickle cell anemia patients: Further evidence for three origins of the sickle cell mutation in Africa

    SciTech Connect

    Chebloune, Y.; Pagnier, J.; Trabuchet, G.; Faure, C.; Verdier, G.; Labie, D.; Nigon, V. )

    1988-06-01

    Haplotype analysis of the {beta}-globin gene cluster shows two regions of DNA characterized by nonrandom association of restriction site polymorphisms. These regions are separated by a variable segment containing the repeated sequences (ATTTT){sub n} and (AT){sub x}T{sub y}, which might be involved in recombinational events. Studies of haplotypes linked to the sickle cell gene in Africa provide strong argument for three origins of the mutation: Benin, Senegal, and the Central African Republic. The structure of the variable segment in the three African populations was studied by S1 nuclease mapping of genomic DNA, which allows a comparison of several samples. A 1080-base-pair DNA segment was sequenced for one sample from each population. S1 nuclease mapping confirmed the homogeneity of each population with regard to both (ATTTT){sub n} and (AT){sub x}T{sub y} repeats. The authors found three additional structures for (AT){sub x}T{sub y} correlating with the geographic origin of the patients. Ten other nucleotide positions, 5{prime} and 3{prime} to the (AT){sub x}T{sub y} copies, were found to be variable when compared to homologous sequences from human and monkey DNAs. These results allow us to propose an evolutionary scheme for the polymorphisms in the 5{prime} flanking region of the {beta}-globin gene. The results strongly support the hypothesis of three origins for the sickle mutation in Africa.

  12. African Outreach Workshop 1974.

    ERIC Educational Resources Information Center

    Schmidt, Nancy J.

    This report discusses the 1974 African Outreach Workshop planned and coordinated by the African Studies Program at the University of Illinois at Urbana-Champaign. Its major aim was to assist teachers in developing curriculum units on African using materials available in their local community. A second aim was for the African Studies Program to…

  13. Detection of a novel recombinant strain of norovirus in an African-descendant community from the Amazon region of Brazil in 2008.

    PubMed

    Fumian, Tulio M; Aragão, Glicélia C; Mascarenhas, Joana D'Arc P; Kaiano, Jane H; Siqueira, Jones Anderson M; Soares, Luana S; Linhares, Alexandre C; Gabbay, Yvone B

    2012-12-01

    Noroviruses, a major cause of acute gastroenteritis outbreaks worldwide, are constantly evolving. This ability is reflected in the speed and efficiency with which these viruses spread and remain in the human population. The present study reports the detection of a novel recombination event among norovirus genotypes in Brazil in 2008. A strain detected in a stool sample from a child with norovirus-associated gastroenteritis, residing in an African-descendant semi-closed community of Pará State, was characterized as a novel intergenotype recombinant, GII.7/GII.20, as determined by partial sequencing and SimPlot analysis. PMID:22872050

  14. Trade in Educational Services: Reflections on the African and South African Higher Education System

    ERIC Educational Resources Information Center

    Sehoole, Chika Trevor

    2004-01-01

    This article discusses and analyses the emergence of globalisation and its impact on developments within the African continent. Africa's response at a regional level through the New Partnership for Africa's Development and at a subregional level through the Southern African Development Community's "Protocol on Education" come under scrutiny. These…

  15. West African crude production diversifies

    SciTech Connect

    Aalund, L.

    1983-06-01

    Nigeria, with its seven crude-oil export streams, dominated West African production and accounted for over 70% of the depressed 1.8 million b/d output from the region last year. However, during the 1970s a flurry of new producing fields, primarily off the African coast, diversified production among a number of countries and touched off a wave of oil activity. The Journal takes a close look at the quality of West African oil in this installment of assays on world export crudes. This issue covers, in alphabetical order, Bonny Light (Nigeria) to Espoir (Ivory Coast). A following issue will wrap up West Africa by presenting assays on crudes from Forcados Blend (Nigeria) to Zaire Crude (Zaire).

  16. Characteristics of African easterly waves associated with tropical cyclogenesis in the Cape Verde Islands region in July-August-September of 2004-2008

    NASA Astrophysics Data System (ADS)

    Arnault, Joël; Roux, Frank

    2011-04-01

    The most common synoptic-scale disturbances related to cyclogenesis over the tropical north Atlantic Ocean are African easterly waves (AEWs) that originated from the northern African continent. However, most of these waves do not evolve in tropical depressions, storms, or hurricanes. The reasons why only few AEWs develop and the necessary conditions for cyclogenetic evolution are still the subject of intense debate. Tropical cyclogenesis occurring near the Cape Verde Islands in the eastern tropical Atlantic is investigated here with five seasons (July-August-September of 2004-2008) of European Centre for Medium-Range Weather Forecasts analyses, Meteosat-9 images, and National Hurricane Center (National Oceanic and Atmospheric Administration, National Centers for Environmental Prediction) "best track" archives. The nine named storms that first reached tropical depression intensity east of 30°W, and two among six which developed between 30 and 40°W, during these five years evolved from intense AEW troughs, associated with low-level cyclonic circulation, weak mid-level anticyclonic Saharan flow to the east, and deep convection near the center of cyclonic vorticity. The cyclogenetic evolution of three AEW troughs, which verified these conditions but failed to develop into named storms, was probably inhibited by unusually dry environment and strong vertical wind shear. The fate of other AEW troughs, which did not satisfy the necessary conditions, is also discussed.

  17. HLA-E coding and 3' untranslated region variability determined by next-generation sequencing in two West-African population samples.

    PubMed

    Castelli, Erick C; Mendes-Junior, Celso T; Sabbagh, Audrey; Porto, Iane O P; Garcia, André; Ramalho, Jaqueline; Lima, Thálitta H A; Massaro, Juliana D; Dias, Fabrício C; Collares, Cristhianna V A; Jamonneau, Vincent; Bucheton, Bruno; Camara, Mamadou; Donadi, Eduardo A

    2015-12-01

    HLA-E is a non-classical Human Leucocyte Antigen class I gene with immunomodulatory properties. Whereas HLA-E expression usually occurs at low levels, it is widely distributed amongst human tissues, has the ability to bind self and non-self antigens and to interact with NK cells and T lymphocytes, being important for immunosurveillance and also for fighting against infections. HLA-E is usually the most conserved locus among all class I genes. However, most of the previous studies evaluating HLA-E variability sequenced only a few exons or genotyped known polymorphisms. Here we report a strategy to evaluate HLA-E variability by next-generation sequencing (NGS) that might be used to other HLA loci and present the HLA-E haplotype diversity considering the segment encoding the entire HLA-E mRNA (including 5'UTR, introns and the 3'UTR) in two African population samples, Susu from Guinea-Conakry and Lobi from Burkina Faso. Our results indicate that (a) the HLA-E gene is indeed conserved, encoding mainly two different protein molecules; (b) Africans do present several unknown HLA-E alleles presenting synonymous mutations; (c) the HLA-E 3'UTR is quite polymorphic and (d) haplotypes in the HLA-E 3'UTR are in close association with HLA-E coding alleles. NGS has proved to be an important tool on data generation for future studies evaluating variability in non-classical MHC genes. PMID:26187162

  18. Increasing the value of health research in the WHO African Region beyond 2015—reflecting on the past, celebrating the present and building the future: a bibliometric analysis

    PubMed Central

    Uthman, Olalekan A; Wiysonge, Charles Shey; Ota, Martin O; Nicol, Mark; Hussey, Gregory D; Ndumbe, Peter M; Mayosi, Bongani M

    2015-01-01

    Objective To assess the profile and determinants of health research productivity in Africa since the onset of the new millennium. Design Bibliometric analysis. Data collection and synthesis In November 2014, we searched PubMed for articles published between 2000 and 2014 from the WHO African Region, and obtained country-level indicators from World Bank data. We used Poisson regression to examine time trends in research publications and negative binomial regression to explore determinants of research publications. Results We identified 107 662 publications, with a median of 727 per country (range 25–31 757). Three countries (South Africa, Nigeria and Kenya) contributed 52% of the publications. The number of publications increased from 3623 in 2000 to 12 709 in 2014 (relative growth 251%). Similarly, the per cent share of worldwide research publications per year increased from 0.7% in 2000 to 1.3% in 2014. The trend analysis was also significant to confirm a continuous increase in health research publications from Africa, with productivity increasing by 10.3% per year (95% CIs +10.1% to +10.5%). The only independent predictor of publication outputs was national gross domestic product. For every one log US$ billion increase in gross domestic product, research publications rose by 105%: incidence rate ratio (IRR=2.05, 95% CI 1.39 to 3.04). The association of private health expenditure with publications was only marginally significant (IRR=1.86, 95% CI 1.00 to 3.47). Conclusions There has been a significant improvement in health research in the WHO African Region since 2000, with some individual countries already having strong research profiles. Countries of the region should implement the WHO Strategy on Research for Health: reinforcing the research culture (organisation); focusing research on key health challenges (priorities); strengthening national health research systems (capacity); encouraging good research practice (standards); and consolidating linkages

  19. Black African Traditional Mathematics

    ERIC Educational Resources Information Center

    Zaslavsky, Claudia

    1970-01-01

    Discusses the traditional number systems and the origin of the number names used by several African peoples living south of the Sahara. Also included are limitations in African mathematical development, and possible topics for research. (RP)

  20. The African Connection

    ERIC Educational Resources Information Center

    Oguntoyinbo, Lekan

    2012-01-01

    From student and faculty exchanges to joint research projects, U.S. universities maintain a broad spectrum of collaborative relationships with African universities. It's unclear how many U.S. colleges and universities have partnerships with African universities. The African Studies Association, an organization of scholars, doesn't keep that kind…

  1. Determination of recent horizontal crustal movements and deformations of African and Eurasian plates in western Mediterranean region using geodetic-GPS computations extended to 2006 (from 1997) related to NAFREF and AFREF frames.

    NASA Astrophysics Data System (ADS)

    Azzouzi, R.

    2009-04-01

    Determination of recent horizontal crustal movements and deformations of African and Eurasian plates in western Mediterranean region using geodetic-GPS computations extended to 2006 (from 1997) related to NAFREF and AFREF frames. By: R. Azzouzi*, M. Ettarid*, El H. Semlali*, et A. Rimi+ * Filière de Formation en Topographie Institut Agronomique et Vétérinaire Hassan II B.P. 6202 Rabat-Instituts MAROC + Département de la Physique du Globe Université Mohammed V Rabat MAROC This study focus on the use of the geodetic spatial technique GPS for geodynamic purposes generally in the Western Mediterranean area and particularly in Morocco. It aims to exploit this technique first to determine the geodetic coordinates on some western Mediterranean sites. And also this technique is used to detect and to determine movements cross the boundary line between the two African and Eurasian crustal plates on some well chosen GPS-Geodynamics sites. It will allow us also to estimate crustal dynamic parameters of tension that results. These parameters are linked to deformations of terrestrial crust in the region. They are also associated with tectonic constraints of the study area. The usefulness of repeated measurements of these elements, the estimate of displacements and the determination of their temporal rates is indisputable. Indeed, sismo-tectonique studies allow a good knowledge of the of earthquake processes, their frequency their amplitude and even of their prediction in the world in general and in Moroccan area especially. They allow also contributing to guarantee more security for all most important management projects, as projects of building great works (dams, bridges, nuclear centrals). And also as preliminary study, for the most important joint-project between Europe and Africa through the Strait of Gibraltar. For our application, 23 GPS monitoring stations under the ITRF2000 reference frame are chosen in Eurasian and African plates. The sites are located around the

  2. Development of a suspension microarray for the genotyping of African swine fever virus targeting the SNPs in the C-terminal end of the p72 gene region of the genome.

    PubMed

    Leblanc, N; Cortey, M; Fernandez Pinero, J; Gallardo, C; Masembe, C; Okurut, A R; Heath, L; van Heerden, J; Sánchez-Vizcaino, J M; Ståhl, K; Belák, S

    2013-08-01

    African swine fever virus (ASFV) causes one of the most dreaded transboundary animal diseases (TADs) in Suidae. African swine fever (ASF) often causes high rates of morbidity and mortality, which can reach 100% in domestic swine. To date, serological diagnosis has the drawback of not being able to differentiate variants of this virus. Previous studies have identified the 22 genotypes based on sequence variation in the C-terminal region of the p72 gene, which has become the standard for categorizing ASFVs. This article describes a genotyping assay developed using a segment of PCR-amplified genomic DNA of approximately 450 bp, which encompasses the C-terminal end of the p72 gene. Complementary paired DNA probes of 15 or 17 bp in length, which are identical except for a single nucleotide polymorphism (SNP) in the central position, were designed to either individually or in combination differentiate between the 22 genotypes. The assay was developed using xMAP technology; probes were covalently linked to microspheres, hybridized to PCR product, labelled with a reporter and read in the Luminex 200 analyzer. Characterization of the sample was performed by comparing fluorescence of the paired SNP probes, that is, the probe with higher fluorescence in a complementary pair identified the SNP that a particular sample possessed. In the final assay, a total of 52 probes were employed, 24 SNP pairs and 4 for general detection. One or more samples from each of the 22 genotypes were tested. The assay was able to detect and distinguish all 22 genotypes. This novel assay provides a powerful novel tool for the simultaneous rapid diagnosis and genotypic differentiation of ASF. PMID:22776009

  3. Development of West African Rainy Seasons (Invited)

    NASA Astrophysics Data System (ADS)

    Cook, K. H.

    2013-12-01

    The development of West African rainy seasons in the observed climatology can be understood in terms of two factors: continentality, i.e., the shape and placement of the African continent, and solar forcing. First, the observed features of the West African spring and summer precipitation climatology that distinguish it from the precipitation climatology of the tropical Atlantic to the east and Central/Eastern Africa to the west are presented. These include a lingering of the precipitation maximum along the Guinean coast in June and the apparent sudden movement of the precipitation maximum into the Sahel in early July. Then, these distinguishing features of the West Africa precipitation climatology are explained in terms of the regional dynamics and, finally, related to continentality and solar forcing through the roles of the African easterly jet, land surface temperature, and seasonally-varying SSTs.

  4. Empowering Women for Development through Community-Driven Sustainable Programmes: A Response to Traditional Patriarchal Power in the Southern African Region

    ERIC Educational Resources Information Center

    Braimoh, Dele; Lekoko, Rebecca; Alade, Eunice B.

    2004-01-01

    In the Southern Africa region, the act of prejudice against women mostly occurs where patriarchal power reigns. This type of power is felt in areas such as inheritance right, division of labour, access to political and economic resources and legal and social matters. Other areas of discrimination against women include access to educational and…

  5. African and non-African admixture components in African Americans and an African Caribbean population.

    PubMed

    Murray, Tanda; Beaty, Terri H; Mathias, Rasika A; Rafaels, Nicholas; Grant, Audrey Virginia; Faruque, Mezbah U; Watson, Harold R; Ruczinski, Ingo; Dunston, Georgia M; Barnes, Kathleen C

    2010-09-01

    Admixture is a potential source of confounding in genetic association studies, so it becomes important to detect and estimate admixture in a sample of unrelated individuals. Populations of African descent in the US and the Caribbean share similar historical backgrounds but the distributions of African admixture may differ. We selected 416 ancestry informative markers (AIMs) to estimate and compare admixture proportions using STRUCTURE in 906 unrelated African Americans (AAs) and 294 Barbadians (ACs) from a study of asthma. This analysis showed AAs on average were 72.5% African, 19.6% European and 8% Asian, while ACs were 77.4% African, 15.9% European, and 6.7% Asian which were significantly different. A principal components analysis based on these AIMs yielded one primary eigenvector that explained 54.04% of the variation and captured a gradient from West African to European admixture. This principal component was highly correlated with African vs. European ancestry as estimated by STRUCTURE (r(2)=0.992, r(2)=0.912, respectively). To investigate other African contributions to African American and Barbadian admixture, we performed PCA on approximately 14,000 (14k) genome-wide SNPs in AAs, ACs, Yorubans, Luhya and Maasai African groups, and estimated genetic distances (F(ST)). We found AAs and ACs were closest genetically (F(ST)=0.008), and both were closer to the Yorubans than the other East African populations. In our sample of individuals of African descent, approximately 400 well-defined AIMs were just as good for detecting substructure as approximately 14,000 random SNPs drawn from a genome-wide panel of markers. PMID:20717976

  6. Tree-ring δ18O in African mahogany (Entandrophragma utile) records regional precipitation and can be used for climate reconstructions

    NASA Astrophysics Data System (ADS)

    van der Sleen, Peter; Groenendijk, Peter; Zuidema, Pieter A.

    2015-04-01

    The availability of instrumental climate data in West and Central Africa is very restricted, both in space and time. This limits the understanding of the regional climate system and the monitoring of climate change and causes a need for proxies that allow the reconstruction of paleoclimatic variability. Here we show that oxygen isotope values (δ18O) in tree rings of Entandrophragma utile from North-western Cameroon correlate to precipitation on a regional to sub-continental scale (1930-2009). All found correlations were negative, following the proposed recording of the 'amount effect' by trees in the tropics. The capacity of E. utile to record the variability of regional precipitation is also confirmed by the significant correlation of tree-ring δ18O with river discharge data (1944-1983), outgoing longwave radiation (a proxy for cloud cover; 1974-2011) and sea surface salinity in the Gulf of Guinea (1950-2011). Furthermore, the high values in the δ18O chronology from 1970 onwards coincide with the Sahel drought period. Given that E. utile presents clear annual growth rings, has a wide-spread distribution in tropical Africa and is long lived (> 250 years), we argue that the analysis of oxygen isotopes in growth rings of this species is a promising tool for the study of paleoclimatic variability during the last centuries in West and Central Africa.

  7. Rain-induced emission pulses of NOx and HCHO from soils in African regions after dry spells as viewed by satellite sensors

    NASA Astrophysics Data System (ADS)

    Zörner, Jan; Penning de Vries, Marloes; Beirle, Steffen; Veres, Patrick; Williams, Jonathan; Wagner, Thomas

    2014-05-01

    Outside industrial areas, soil emissions of NOx (stemming from bacterial emissions of NO) represent a considerable fraction of total NOx emissions, and may even dominate in remote tropical and agricultural areas. NOx fluxes from soils are controlled by abiotic and microbiological processes which depend on ambient environmental conditions. Rain-induced spikes in NOx have been observed by in-situ measurements and also satellite observations. However, the estimation of soil emissions over broad geographic regions remains uncertain using bottom-up approaches. Independent, global satellite measurements can help constrain emissions used in chemical models. Laboratory experiments on soil fluxes suggest that significant HCHO emissions from soil can occur. However, it has not been previously attempted to detect HCHO emissions from wetted soils by using satellite observations. This study investigates the evolution of tropospheric NO2 (as a proxy for NOx) and HCHO column densities before and after the first rain fall event following a prolonged dry period in semi-arid regions, deserts as well as tropical regions in Africa. Tropospheric NO2 and HCHO columns retrieved from OMI aboard the AURA satellite, GOME-2 aboard METOP and SCIAMACHY aboard ENVISAT are used to study and inter-compare the observed responses of the trace gases with multiple space-based instruments. The observed responses are prone to be affected by other sources like lightning, fire, influx from polluted air masses, as well measurement errors in the satellite retrieval caused by manifold reasons such as an increased cloud contamination. Thus, much care is taken verify that the observed spikes reflect enhancements in soil emissions. Total column measurements of H2O from GOME-2 give further insight into the atmospheric state and help to explain the increase in humidity before the first precipitation event. The analysis is not only conducted for averages of distinct geographic regions, i.e. the Sahel, but also

  8. Effect of background and transport dose on the results of the personal dose equivalent Hp(10) measurements in photon fields obtained during the intercomparison 2013 of the African region.

    PubMed

    Arib, M; Herrati, A; Dari, F; Lounis-Mokrani, Z

    2015-12-01

    As part of the intercomparison on the measurement of personal dose equivalent Hp(10), jointly organised by the International Atomic Energy Agency and the Algerian Secondary Standard Dosimetry Laboratory, for the African region, up to 12 dosemeters were added to the packages of the 28 participants to evaluate the background and transport dose (BGTD), received by the dosemeters before and after their irradiation at the SSDL (environmental irradiations, scanning process at the airports, etc.). Out of the 28 participants, only 17 reported the corresponding BGTD measured values, which lied between 0.03 and 0.8 mSv. The mean measured value of BG was (0.25±0.14) mSv, which is significantly high compared with the lowest dose value used in the intercomparison exercise. The BGTD correction shifted the overall results of the intercomparison from an overestimation of dose (∼8 % before applying BGT dose correction) to an underestimation of dose (-9 % after correction). The measurement protocol and the detailed analysis of the results and applied corrections are discussed in this paper. PMID:25433048

  9. 16 Extraordinary African Americans.

    ERIC Educational Resources Information Center

    Lobb, Nancy

    This collection for children tells the stories of 16 African Americans who helped make America what it is today. African Americans can take pride in the heritage of these contributors to society. Biographies are given for the following: (1) Sojourner Truth, preacher and abolitionist; (2) Frederick Douglass, abolitionist; (3) Harriet Tubman, leader…

  10. African Studies Computer Resources.

    ERIC Educational Resources Information Center

    Kuntz, Patricia S.

    African studies computer resources that are readily available in the United States with linkages to Africa are described, highlighting those most directly corresponding to African content. Africanists can use the following four fundamental computer systems: (1) Internet/Bitnet; (2) Fidonet; (3) Usenet; and (4) dial-up bulletin board services. The…

  11. African Literature as Celebration.

    ERIC Educational Resources Information Center

    Achebe, Chinua

    1989-01-01

    Describes the Igbo tradition of "Mbari," a communal creative enterprise that celebrates the world and the life lived in it through art. Contrasts the cooperative, social dimension of pre-colonial African culture with the exclusion and denial of European colonialism, and sees new African literature again celebrating human presence and dignity. (AF)

  12. Educating African American Males

    ERIC Educational Resources Information Center

    Bell, Edward E.

    2010-01-01

    Background: Schools across America spend money, invest in programs, and sponsor workshops, offer teacher incentives, raise accountability standards, and even evoke the name of Obama in efforts to raise the academic achievement of African American males. Incarceration and college retention rates point to a dismal plight for many African American…

  13. Africans Away from Home.

    ERIC Educational Resources Information Center

    Clarke, John Henrik

    Africans who were brought across the Atlantic as slaves never fully adjusted to slavery or accepted its inevitability. Resistance began on board the slave ships, where many jumped overboard or committed suicide. African slaves in South America led the first revolts against tyranny in the New World. The first slave revolt in the Caribbean occurred…

  14. Keeping African Masks Real

    ERIC Educational Resources Information Center

    Waddington, Susan

    2012-01-01

    Art is a good place to learn about our multicultural planet, and African masks are prized throughout the world as powerfully expressive artistic images. Unfortunately, multicultural education, especially for young children, can perpetuate stereotypes. Masks taken out of context lose their meaning and the term "African masks" suggests that there is…

  15. Diabetes in African Americans

    PubMed Central

    Marshall, M

    2005-01-01

    African Americans have a high risk for type 2 diabetes. Genetic traits, the prevalence of obesity, and insulin resistance all contribute to the risk of diabetes in the African American community. African Americans have a high rate of diabetic complications, because of poor glycaemic control and racial disparities in health care in the USA. African Americans with diabetes may have an atypical presentation that simulates type 1 diabetes, but then their subsequent clinical course is typical of type 2 diabetes. Culturally sensitive strategies, structured disease management protocols, and the assistance of nurses, diabetic educators, and other health care professionals are effective in improving the outcome of diabetes in the African American community. PMID:16344294

  16. Evolution of the primate beta-globin gene region: nucleotide sequence of the delta-beta-globin intergenic region of gorilla and phylogenetic relationships between African apes and man.

    PubMed

    Perrin-Pecontal, P; Gouy, M; Nigon, V M; Trabuchet, G

    1992-01-01

    A 6.0-kb DNA fragment from Gorilla gorilla including the 5' part of the beta-globin gene and about 4.5 kb of its upstream flanking region was cloned and sequenced. The sequence was compared to the human, chimpanzee, and macaque delta-beta intergenic region. This analysis reveals four tandemly repeated sequences (RS), at the same location in the four species, showing a variable number of repeats generating both intraspecific (polymorphism) and interspecific variability. These tandem arrays delimit five regions of unique sequence called IG for intergenic. The divergence for these IG sequences is 1.85 +/- 0.22% between human and gorilla, which is not significantly different from the value estimated in the same region between chimpanzee and human (1.62 +/- 0.21%). The CpG and TpA dinucleotides are avoided. CpGs evolve faster than other sequence sites but do not confuse phylogenetic inferences by producing parallel mutations in different lineages. About 75% of CpG doublets have become TpG or CpA since the common ancestor, in agreement with the methylation/deamination pattern. Comparison of this intergenic region gives information on branching order within Hominoidea. Parsimony and distance-based methods when applied to the delta-beta intergenic region provide evidence (although not statistically significant) that human and chimpanzee are more closely related to each other than to gorilla. CpG sites are indeed rich in information by carrying substitutions along the short internal branch. Combining these results with those on the psi eta-delta intergenic region, shows in a statistically significant way that chimpanzee is the closest relative of human. PMID:1556740

  17. African bees to control African elephants

    NASA Astrophysics Data System (ADS)

    Vollrath, Fritz; Douglas-Hamilton, Iain

    2002-11-01

    Numbers of elephants have declined in Africa and Asia over the past 30 years while numbers of humans have increased, both substantially. Friction between these two keystone species is reaching levels which are worryingly high from an ecological as well as a political viewpoint. Ways and means must be found to keep the two apart, at least in areas sensitive to each species' survival. The aggressive African bee might be one such method. Here we demonstrate that African bees deter elephants from damaging the vegetation and trees which house their hives. We argue that bees can be employed profitably to protect not only selected trees, but also selected areas, from elephant damage.

  18. Comparison of GPS-TEC with IRI-2012 TEC over African equatorial and low latitude regions during the period of 2012-2013

    NASA Astrophysics Data System (ADS)

    Tariku, Yekoye Asmare

    2015-10-01

    This paper presents the performance of the latest version of the International Reference Ionosphere (IRI-2012) model in estimating the Vertical Total Electron Content (VTEC) variation over equatorial and low latitude East Africa regions during the period of 2012-2013. This has been conducted by comparing the ground-based Global Positioning System (GPS) VTEC inferred from nine dual frequency GPS receivers installed at different regions in the continent. In this work, the diurnal, monthly and seasonal variation in the measured VTEC have been analyzed and compared with the VTEC obtained from IRI-2012 model. It is depicted that the lowest diurnal peaks of the modeled and measured VTEC values are observed in the June solstice months, whereas the highest values are observed in the equinoctial months. The variability of the diurnal GPS-VTEC is also found to be minimal nearly at 03:00 UT and maximal mostly between 09:00 and 14:00 UT. Moreover, the maximum and minimum monthly mean hourly measured VTEC values inferred from both the Arba Minch and Entebbe stations are observed in October and July, respectively. Similarly, the highest and the lowest seasonal mean hourly measured VTEC values are observed in the September equinox and in the June solstice, respectively. The model predictions generally follow the diurnal variations of the measured VTEC, with minimum value at predawn hours and maximum at noontime hours (10:00-13:00 UT). It has been shown that the model better estimates the diurnal VTEC values mostly just after midnight hours (00:00-03:00 UT). Good agreements between the modeled and measured monthly and seasonal mean hourly VTEC values obtained from Arba Minch station are also observed in the equinoctial months. But, for the Entebbe station, the modeled monthly and seasonal VTEC values are larger than the corresponding measured VTEC values by about 75% and 60%, respectively. In addition, there are large discrepancies observed between the diurnal measured and modeled

  19. Y chromosome lineages in men of west African descent.

    PubMed

    Torres, Jada Benn; Doura, Menahem B; Keita, Shomarka O Y; Kittles, Rick A

    2012-01-01

    The early African experience in the Americas is marked by the transatlantic slave trade from ∼1619 to 1850 and the rise of the plantation system. The origins of enslaved Africans were largely dependent on European preferences as well as the availability of potential laborers within Africa. Rice production was a key industry of many colonial South Carolina low country plantations. Accordingly, rice plantations owners within South Carolina often requested enslaved Africans from the so-called "Grain Coast" of western Africa (Senegal to Sierra Leone). Studies on the African origins of the enslaved within other regions of the Americas have been limited. To address the issue of origins of people of African descent within the Americas and understand more about the genetic heterogeneity present within Africa and the African Diaspora, we typed Y chromosome specific markers in 1,319 men consisting of 508 west and central Africans (from 12 populations), 188 Caribbeans (from 2 islands), 532 African Americans (AAs from Washington, DC and Columbia, SC), and 91 European Americans. Principal component and admixture analyses provide support for significant Grain Coast ancestry among African American men in South Carolina. AA men from DC and the Caribbean showed a closer affinity to populations from the Bight of Biafra. Furthermore, 30-40% of the paternal lineages in African descent populations in the Americas are of European ancestry. Diverse west African ancestries and sex-biased gene flow from EAs has contributed greatly to the genetic heterogeneity of African populations throughout the Americas and has significant implications for gene mapping efforts in these populations. PMID:22295064

  20. Y Chromosome Lineages in Men of West African Descent

    PubMed Central

    Keita, Shomarka O. Y.; Kittles, Rick A.

    2012-01-01

    The early African experience in the Americas is marked by the transatlantic slave trade from ∼1619 to 1850 and the rise of the plantation system. The origins of enslaved Africans were largely dependent on European preferences as well as the availability of potential laborers within Africa. Rice production was a key industry of many colonial South Carolina low country plantations. Accordingly, rice plantations owners within South Carolina often requested enslaved Africans from the so-called “Grain Coast” of western Africa (Senegal to Sierra Leone). Studies on the African origins of the enslaved within other regions of the Americas have been limited. To address the issue of origins of people of African descent within the Americas and understand more about the genetic heterogeneity present within Africa and the African Diaspora, we typed Y chromosome specific markers in 1,319 men consisting of 508 west and central Africans (from 12 populations), 188 Caribbeans (from 2 islands), 532 African Americans (AAs from Washington, DC and Columbia, SC), and 91 European Americans. Principal component and admixture analyses provide support for significant Grain Coast ancestry among African American men in South Carolina. AA men from DC and the Caribbean showed a closer affinity to populations from the Bight of Biafra. Furthermore, 30–40% of the paternal lineages in African descent populations in the Americas are of European ancestry. Diverse west African ancestries and sex-biased gene flow from EAs has contributed greatly to the genetic heterogeneity of African populations throughout the Americas and has significant implications for gene mapping efforts in these populations. PMID:22295064

  1. Black versus Black: The Relationship among African, African American, and African Caribbean Persons.

    ERIC Educational Resources Information Center

    Jackson, Jennifer V.; Cothran, Mary E.

    2003-01-01

    Surveyed people of African descent regarding relationships among African, African-American, and African-Caribbean persons, focusing on contact and friendship, travel to countries of the diaspora, cross-cultural communication, thoughts and stereotypes, and education. Most respondents had contacts with the other groups, but groups had preconceived…

  2. African American Suicide

    MedlinePlus

    ... accounted for 83.8% of Caucasian elderly suicides. • Firearms were the predominant method of suicide among African ... per 100,000 annually. Source: Centers for Disease Control and Prevention. National Vital Statistics System. Mortality Data. ...

  3. Toward a Caribbean psychology: an African-centered approach.

    PubMed

    Sutherland, Marcia Elizabeth

    2011-01-01

    Although the Americas and Caribbean region are purported to comprise different ethnic groups, this article’s focus is on people of African descent, who represent the largest ethnic group in many countries. The emphasis on people of African descent is related to their family structure, ethnic identity, cultural, psychohistorical, and contemporary psychosocial realities. This article discusses the limitations of Western psychology for theory, research, and applied work on people of African descent in the Americas and Caribbean region. In view of the adaptations that some people of African descent have made to slavery, colonialism, and more contemporary forms of cultural intrusions, it is argued that when necessary, notwithstanding Western psychology’s limitations, Caribbean psychologists should reconstruct mainstream psychology to address the psychological needs of these Caribbean people. The relationship between theory and psychological interventions for the optimal development of people of African descent is emphasized throughout this article. In this regard, the African-centered and constructionist viewpoint is argued to be of utility in addressing the psychological growth and development of people of African descent living in the Americas and Caribbean region. PMID:22013618

  4. Abundance of African invader fly, Bactrocera invadens drew, tsuruta and white (diptera: tephritidae) and influence of weather parameters on trap catches in mango in the Volta region of Ghana.

    PubMed

    Adzim, Charles Amankwa; Billah, Maxwell Kelvin; Afreh-Nuamah, Kwame

    2016-01-01

    The seasonal abundance of African Invader fly, Bactrocera invadens and the influence of temperature and rainfall on fly catches was determined in two agro ecological zones; moist semi-deciduous forest area and the coastal grassland area of the Volta Region of Ghana for year of mango production. Traps containing methyl eugenol were used in monitoring the abundance of the Africa invader fly, Bactrocera invadens where data on both temperature and rainfall were collected from Meteorological Services of Ghana in Volta region. A total of 49,322 organisms captured, 45,829 were identified as Bactrocera invadens and 3493 were non-fruit fly. There were significant differences (p < 0.05) in the number of Bactrocera invadens captured between the agro ecological zones with relative fly densities of 5.06 F/T/D in moist semi deciduous forest area and 2.38 F/T/D in the coastal grassland zone. The result shows that climatic factors affected Bactrocera invadens differently in different agro ecological area. There was negative correlation and highly significant (p < 0.001) correlation between fruit flies and temperature whereas there was negative correlation and high significant (p < 0.01) difference between rainfall in the moist semi deciduous forest area. In the coastal grassland area, there was negative correlation and highly significant (p < 0.001) between Bactrocera invadens for both rainfall and temperature. Bactrocera invadens activities peaked differently during the study period due to favourable climatic conditions. The activities of Bactrocera invadens peaked during weeks 7 and 29 in the moist semi deciduous forest area while their activities peaked during weeks 3 and 24 for the coastal grassland areas. Both agro ecological zones recorded the presence of Bactrocera invadens, their number and proportion varied considerably with associated effects of the weather parameters on their abundance. The effect of weather parameters on the abundance of bactrocera invadens

  5. African diatom palaeoecology and biostratigraphy

    NASA Astrophysics Data System (ADS)

    Gasse, F.; Fourtanier, E.

    This paper illustrates the different types of information which can be deduced from African diatoms studies. The first section is devoted to the reconstruction of palaeoenvironments. The accuracy of ecological data (estimates of ecological variables e.g. types of habitats, water chemistry…) depends on the times scale and on the spatial scale considered: short-term environments in a given waterbody, environmental evolution during individual humid episodes considered locally or regionally, long-term changes in diatom flora induced by major climatic tendencies at a regional or continental scale. One then summarizes our present state of knowledge in diatom biostratigraphy in Africa. Several centric taxa, belonging to the genera Aulacoseira, Mesodictyon, Cyclotella, Stephanodiscus and Cyclostephanos appear to have limited stratigraphical ranges and to be good chronological markers.

  6. Population affinities of African Colombians to Sub-Saharan Africans based on dental morphology.

    PubMed

    Delgado-Burbano, M E

    2007-01-01

    The Atlantic slave trade moved more than 13 million Africans to American lands between the 15th and 19th centuries. Previous historical, linguistic, and social-cultural studies suggested a Western-Central Bantu African origin for the Colombian slaves; however, their precise provenance remains unclear. The present study investigates the variation of the epigenetic dental traits in the deciduous and permanent dentition and phenotypic affinities of a contemporary Afro-Colombian community (n=178) in an attempt to identify their possible African ancestors. The results of a multivariate analysis of principal components show that Afro-descendents from Guapi have strong phenotypic relationships with several Bantu-speakers groups of Western and Western-Central Africa (Sub-Saharan region), specifically from Gabon, Congo, Pygmies, Nigeria, Cameroon, Togo and Benin. In concordance with recent mtDNA studies, this research suggests a distant but important relationship between Afro-Colombians and Eastern and South-Eastern African populations. This analysis also shows a marked dental divergence with North African samples. The dental information is not very different from the cultural, linguistic and historic data; however, it is more in agreement with studies based on molecular variation. In addition, this study reveals that African-Americans from North America, Central America-Caribbean and South America have high biological variation essentially identical to their several Sub-Saharan sources. Although a microevolutionary model, based on differential rates of gene flow with Native American and European-American groups and little selective pressures influence, better explains the phenotypic variation observed, more African-American dental samples must be analyzed from a regional perspective. PMID:17675007

  7. The Great Migration and African-American Genomic Diversity

    PubMed Central

    Barakatt, Maxime; Gignoux, Christopher R.; Errington, Jacob; Blot, William J.; Bustamante, Carlos D.; Kenny, Eimear E.; Williams, Scott M.; Aldrich, Melinda C.; Gravel, Simon

    2016-01-01

    We present a comprehensive assessment of genomic diversity in the African-American population by studying three genotyped cohorts comprising 3,726 African-Americans from across the United States that provide a representative description of the population across all US states and socioeconomic status. An estimated 82.1% of ancestors to African-Americans lived in Africa prior to the advent of transatlantic travel, 16.7% in Europe, and 1.2% in the Americas, with increased African ancestry in the southern United States compared to the North and West. Combining demographic models of ancestry and those of relatedness suggests that admixture occurred predominantly in the South prior to the Civil War and that ancestry-biased migration is responsible for regional differences in ancestry. We find that recent migrations also caused a strong increase in genetic relatedness among geographically distant African-Americans. Long-range relatedness among African-Americans and between African-Americans and European-Americans thus track north- and west-bound migration routes followed during the Great Migration of the twentieth century. By contrast, short-range relatedness patterns suggest comparable mobility of ∼15–16km per generation for African-Americans and European-Americans, as estimated using a novel analytical model of isolation-by-distance. PMID:27232753

  8. The Great Migration and African-American Genomic Diversity.

    PubMed

    Baharian, Soheil; Barakatt, Maxime; Gignoux, Christopher R; Shringarpure, Suyash; Errington, Jacob; Blot, William J; Bustamante, Carlos D; Kenny, Eimear E; Williams, Scott M; Aldrich, Melinda C; Gravel, Simon

    2016-05-01

    We present a comprehensive assessment of genomic diversity in the African-American population by studying three genotyped cohorts comprising 3,726 African-Americans from across the United States that provide a representative description of the population across all US states and socioeconomic status. An estimated 82.1% of ancestors to African-Americans lived in Africa prior to the advent of transatlantic travel, 16.7% in Europe, and 1.2% in the Americas, with increased African ancestry in the southern United States compared to the North and West. Combining demographic models of ancestry and those of relatedness suggests that admixture occurred predominantly in the South prior to the Civil War and that ancestry-biased migration is responsible for regional differences in ancestry. We find that recent migrations also caused a strong increase in genetic relatedness among geographically distant African-Americans. Long-range relatedness among African-Americans and between African-Americans and European-Americans thus track north- and west-bound migration routes followed during the Great Migration of the twentieth century. By contrast, short-range relatedness patterns suggest comparable mobility of ∼15-16km per generation for African-Americans and European-Americans, as estimated using a novel analytical model of isolation-by-distance. PMID:27232753

  9. AILA Africa Research Network Launch 2007: Research into the Use of the African Languages for Academic Purposes

    ERIC Educational Resources Information Center

    Wildsmith-Cromarty, Rosemary

    2009-01-01

    The aim of the one-day symposium was to bring together scholars in applied linguistics with an interest in the African languages for the launch of the new AILA Africa regional network. Contributions were in the form of invited research papers from several African countries. This report focuses on the South African contribution, which highlighted…

  10. An African-American family with dystonia.

    PubMed

    Puschmann, Andreas; Xiao, Jianfeng; Bastian, Robert W; Searcy, Jill A; LeDoux, Mark S; Wszolek, Zbigniew K

    2011-08-01

    The genetic cause of late-onset focal and segmental dystonia remains unknown in most individuals. Recently, mutations in Thanatos-associated protein domain containing, apoptosis associated protein 1 (THAP1) have been described in DYT6 dystonia and associated with some cases of familial and sporadic late-onset dystonia in Caucasians. We are not aware of any previous descriptions of familial dystonia in African-Americans or reports of THAP1 mutations in African-Americans. Herein, we characterize an African-American (AA) kindred with late-onset primary dystonia, clinically and genetically. The clinical phenotype included cervical, laryngeal and hand-forearm dystonia. Symptoms were severe and disabling for several family members, whereas others only displayed mild signs. There were no accompanying motor or cognitive signs. In this kindred, age of onset ranged from 45 to 50 years and onset was frequently sudden, with symptoms developing within weeks or months. DYT1 was excluded as the cause of dystonia in this kindred. The entire genomic region of THAP1, including non-coding regions, was sequenced. We identified 13 sequence variants in THAP1, although none co-segregated with dystonia. A novel THAP1 variant (c.-237-3G>T/A) was found in 3/84 AA dystonia patient alleles and 3/212 AA control alleles, but not in 5870 Caucasian alleles. In summary, although previously unreported, familial primary dystonia does occur in African-Americans. Genetic analysis of the entire genomic region of THAP1 revealed a novel variant that was specific for African-Americans. Therefore, genetic testing for dystonia and future studies of candidate genes must take genetic background into consideration. PMID:21601506

  11. An African-American Family with Dystonia

    PubMed Central

    Puschmann, Andreas; Xiao, Jianfeng; Bastian, Robert W.; Searcy, Jill A.; LeDoux, Mark S.; Wszolek, Zbigniew K.

    2011-01-01

    The genetic cause of late-onset focal and segmental dystonia remains unknown in most individuals. Recently, mutations in Thanatos-associated protein domain containing, apoptosis associated protein 1 (THAP1) have been described in DYT6 dystonia and associated with some cases of familial and sporadic late-onset dystonia in Caucasians. We are not aware of any previous descriptions of familial dystonia in African Americans or reports of THAP1 mutations in African Americans. Herein, we characterize an African-American (AA) kindred with late-onset primary dystonia, clinically and genetically. The clinical phenotype included cervical, laryngeal and hand-forearm dystonia. Symptoms were severe and disabling for several family members, whereas others only displayed mild signs. There were no accompanying motor or cognitive signs. In this kindred, age of onset ranged from 45 to 50 years and onset was frequently sudden, with symptoms developing within weeks or months. DYT1 was excluded as the cause of dystonia in this kindred. The entire genomic region of THAP1, including non-coding regions, was sequenced. We identified 13 sequence variants in THAP1, although none co-segregated with dystonia. A novel THAP1 variant (c.-237-3G>T/A) was found in 3/84 AA dystonia patient alleles and 3/212 AA control alleles, but not in 5,870 Caucasian alleles. In summary, although previously unreported, familial primary dystonia does occur in African Americans. Genetic analysis of the entire genomic region of THAP1 revealed a novel variant that was specific for African Americans. Therefore, genetic testing for dystonia and future studies of candidate genes must take genetic background into consideration. PMID:21601506

  12. Ideal Body Size as a Mediator for the Gender-Specific Association between Socioeconomic Status and Body Mass Index: Evidence from an Upper-Middle-Income Country in the African Region

    ERIC Educational Resources Information Center

    Yepes, Maryam; Maurer, Jürgen; Stringhini, Silvia; Viswanathan, Barathi; Gedeon, Jude; Bovet, Pascal

    2016-01-01

    Background: While obesity continues to rise globally, the associations between body size, gender, and socioeconomic status (SES) seem to vary in different populations, and little is known on the contribution of perceived ideal body size in the social disparity of obesity in African countries. Purpose: We examined the gender and socioeconomic…

  13. Cross-Reactivity of Filariais ICT Cards in Areas of Contrasting Endemicity of Loa loa and Mansonella perstans in Cameroon: Implications for Shrinking of the Lymphatic Filariasis Map in the Central African Region

    PubMed Central

    Wanji, Samuel; Koudou, Benjamin; Chounna Ndongmo, Patrick W.; Kengne-Ouafo, Jonas A.; Datchoua-Poutcheu, Fabrice R.; Fovennso, Bridget Adzemye; Tayong, Dizzle Bita; Fombad, Fanny Fri; Fischer, Peter U.; Enyong, Peter I.; Bockarie, Moses

    2015-01-01

    : a rate of 1% or more of positive ICT results was found only in areas with an L. loa Mf prevalence above 15%. In contrast, there was no association between ICT positivity and M. perstans prevalence (Spearman’s rho = - 0.200; p = 0.747) and Mf density (Odds ratio = 1.8; 95%CI: 0.8–4.2; p = 0.192). Conclusions/Significance This study has confirmed the strong association between the ICT positivity and L. loa intensity (Mf/ml of blood) at the individual level. Furthermore, the study has demonstrated that ICT positivity is strongly associated with high L. loa prevalence. These results suggest that the main confounding factor for positive ICT test card results are high levels of L. loa. The findings may indicate that W. bancrofti is much less prevalent in the Central African region where L. loa is highly endemic than previously assumed and accurate re-mapping of the region would be very useful for shrinking of the map of LF distribution. PMID:26544042

  14. Investigating the Impacts of Surface Temperature Anomalies Due to Wildfires in Northern Sub-Saharan Africa

    NASA Astrophysics Data System (ADS)

    Gabbert, T.; Ichoku, C. M.; Matsui, T.; Capehart, W. J.

    2014-12-01

    The northern Sub-Saharan African region (NSSA) is an area of intense study due to the recent severe droughts that have dire consequences on the population, which relies mostly on rainfed agriculture for its food supply. This region's weather and hydrologic cycle are very complex and are dependent on the West African Monsoon. Different regional processes affect the West African Monsoon cycle and variability. One of the areas of current investigation is the water cycle response to the variability of land surface characteristics. Land surface characteristics are often altered in NSSA due to agricultural practices, grazing, and the fires that occur during the dry season. To better understand the effects of biomass burning on the hydrologic cycle of the sub-Saharan environment, an interdisciplinary team sponsored by NASA is analyzing potential feedback mechanisms due to the fires. As part of this research, this study focuses on the effects of land surface changes, particularly albedo and skin temperature, that are influenced by biomass burning. Surface temperature anomalies can influence the initiation of convective rainfall and surface albedo is linked to the absorption of solar radiation. To capture the effects of fire perturbations on the land surface, NASA's Unified Weather and Research Forecasting (NU-WRF) model coupled with NASA's Land Information System (LIS) is being used to simulate some of the fire-induced surface temperature anomalies and other environmental processes. In this presentation, we will report the strategy for these simulations, and show some preliminary results.

  15. African-Americans and Alzheimer's

    MedlinePlus

    ... Share Plus on Google Plus African-Americans and Alzheimer's alz.org | IHaveAlz Introduction 10 Warning Signs Brain ... African-Americans are at a higher risk for Alzheimer's disease. Many Americans dismiss the warning signs of ...

  16. The Struggles over African Languages

    ERIC Educational Resources Information Center

    Maseko, Pam; Vale, Peter

    2016-01-01

    In this interview, African Language expert Pam Maseko speaks of her own background and her first encounter with culture outside of her mother tongue, isiXhosa. A statistical breakdown of South African languages is provided as background. She discusses Western (originally missionary) codification of African languages and suggests that this approach…

  17. Psychological Misdiagnosis of African Americans.

    ERIC Educational Resources Information Center

    Garretson, Deborah J.

    1993-01-01

    Reviews historical and current problems with making accurate psychological diagnoses of African Americans. Suggests that misdiagnosis is strongly related to pathologization of African-American culture itself. Explores diagnostic process, stereotypes of African-American psychopathology, cultural differences in values and life stressors, and…

  18. Narcolepsy in African Americans

    PubMed Central

    Kawai, Makoto; O'Hara, Ruth; Einen, Mali; Lin, Ling; Mignot, Emmanuel

    2015-01-01

    Study Objectives: Although narcolepsy affects 0.02–0.05% of individuals in various ethnic groups, clinical presentation in different ethnicities has never been fully characterized. Our goal was to study phenotypic expression across ethnicities in the United States. Design/Setting: Cases of narcolepsy from 1992 to 2013 were identified from searches of the Stanford Center for Narcolepsy Research database. International Classification of Sleep Disorders, Third Edition diagnosis criteria for type 1 and type 2 narcolepsy were used for inclusion, but subjects were separated as with and without cataplexy for the purpose of data presentation. Information extracted included demographics, ethnicity and clinical data, HLA-DQB1*06:02, polysomnography (PSG), multiple sleep latency test (MSLT) data, and cerebrospinal fluid (CSF) hypocretin-1 level. Patients: 182 African-Americans, 839 Caucasians, 35 Asians, and 41 Latinos with narcolepsy. Results: Sex ratio, PSG, and MSLT findings did not differ across ethnicities. Epworth Sleepiness Scale (ESS) score was higher and age of onset of sleepiness earlier in African Americans compared with other ethnicities. HLA-DQB1*06:02 positivity was higher in African Americans (91.0%) versus others (76.6% in Caucasians, 80.0% in Asians, and 65.0% in Latinos). CSF hypocretin-1 level, obtained in 222 patients, was more frequently low (≤ 110 pg/ml) in African Americans (93.9%) versus Caucasians (61.5%), Asians (85.7%) and Latinos (75.0%). In subjects with low CSF hypocretin-1, African Americans (28.3%) were 4.5 fold more likely to be without cataplexy when compared with Caucasians (8.1%). Conclusions: Narcolepsy in African Americans is characterized by earlier symptom onset, higher Epworth Sleepiness Scale score, higher HLA-DQB1*06:02 positivity, and low cerebrospinal fluid hypocretin-1 level in the absence of cataplexy. In African Americans, more subjects without cataplexy have type 1 narcolepsy. Citation: Kawai M, O'Hara R, Einen M, Lin L

  19. The Genetic Structure and History of Africans and African Americans

    PubMed Central

    Tishkoff, Sarah A.; Reed, Floyd A.; Friedlaender, Françoise R.; Ehret, Christopher; Ranciaro, Alessia; Froment, Alain; Hirbo, Jibril B.; Awomoyi, Agnes A.; Bodo, Jean-Marie; Doumbo, Ogobara; Ibrahim, Muntaser; Juma, Abdalla T.; Kotze, Maritha J.; Lema, Godfrey; Moore, Jason H.; Mortensen, Holly; Nyambo, Thomas B.; Omar, Sabah A.; Powell, Kweli; Pretorius, Gideon S.; Smith, Michael W.; Thera, Mahamadou A.; Wambebe, Charles; Weber, James L.; Williams, Scott M.

    2010-01-01

    Africa is the source of all modern humans, but characterization of genetic variation and of relationships among populations across the continent has been enigmatic. We studied 121 African populations, four African American populations, and 60 non-African populations for patterns of variation at 1327 nuclear microsatellite and insertion/deletion markers. We identified 14 ancestral population clusters in Africa that correlate with self-described ethnicity and shared cultural and/or linguistic properties. We observed high levels of mixed ancestry in most populations, reflecting historical migration events across the continent. Our data also provide evidence for shared ancestry among geographically diverse hunter-gatherer populations (Khoesan speakers and Pygmies). The ancestry of African Americans is predominantly from Niger-Kordofanian (~71%), European (~13%), and other African (~8%) populations, although admixture levels varied considerably among individuals. This study helps tease apart the complex evolutionary history of Africans and African Americans, aiding both anthropological and genetic epidemiologic studies. PMID:19407144

  20. Two Distinct mtDNA Lineages among Captive African Penguins in Japan

    PubMed Central

    MURATA, Michiko; MURAKAMI, Masaru

    2013-01-01

    ABSTRACT The African penguin (Spheniscus demersus) is one of the world’s most endangered seabirds. In Japan, although the number of African penguins in captivity continues to increase, genetic data have not been collected for either wild or captive populations. To reveal genetic diversity and characterization in captive African penguins, we analyzed the nucleotide sequences of mitochondrial DNA (mtDNA) from a sample of 236 African penguins. Analysis of 433 bp of the control region and 1,140 bp of cytochrome b sequences revealed the existence of two mtDNA clades. Control region haplotypes were much more divergent (d=3.39%) between the two clades than within each clade. The divergence of these clades may reflect differences at the subspecies or geographical population level in African penguins. These findings suggest that at least two distinct maternal lineages exist in the wild populations of the African penguin. PMID:24317269

  1. The Other African Americans.

    ERIC Educational Resources Information Center

    Matory, J. Lorand

    Black North America is ethnically and culturally diverse. It contains many groups who do not call themselves or have not always called themselves "Negro,""Black,""African-American," and so forth, such as Louisiana Creoles of color and many of the Indian tribes east of the Mississippi. There are also numerous North American ethnic groups of African…

  2. African American rhinoplasty.

    PubMed

    Boyette, Jennings R; Stucker, Fred J

    2014-08-01

    Rhinoplasty in patients of African descent requires a patient-specific approach, because the goals and ideal proportions differ from the white nose. This article discusses approaches to surgical correction of common anatomic variations. In addition, common pitfalls are outlined. PMID:25049123

  3. Elective: African Literature.

    ERIC Educational Resources Information Center

    Jenkins, Kenneth V.

    The make-up of a course in African literature for high school students is discussed. It is pointed out that the course can be constructed on already familiar lines. High school students will be able to describe clearly, for example, the relationship between environment and character or the dilemma of characters caught between traditional values…

  4. Role of inertial instability in the West African monsoon jump

    NASA Astrophysics Data System (ADS)

    Cook, Kerry H.

    2015-04-01

    The West African monsoon jump is a sudden shift in the latitude of the West African precipitation maximum from the Guinean coast near 4°N into Sahel near 12°N in late June or early July. An examination of reanalyses and observations indicates that the Sahel rainy season develops smoothly and the monsoon jump occurs because of an abrupt decrease in Guinean coast rainfall. We show that this abrupt end of the coastal rainy season occurs when inertial instability develops over the region, 1 month later than it develops in the vicinity of the marine Atlantic Intertropical Convergence Zone. The reason for this delay is the presence of the African easterly jet, which places strong negative meridional zonal wind gradients over the coast to preserve the inertially stable environment. When the African easterly jet moves farther north due to the seasonal solar forcing, these gradients weaken and then reverse to satisfy the threshold condition for inertial instability; the rapid end of the Guinean coast rainy season follows. The northward movement and intensity of the African easterly jet are controlled by the seasonal development of strong meridional land surface temperature gradients and are independent of the formation of the Atlantic cold tongue. This explanation for the West African monsoon jump relates the phenomenon to the shape and location of the African continent, including the low-latitude position of the Guinean coast and the large expanse of the continent to the north.

  5. African Ancestry Is Associated with Asthma Risk in African Americans

    PubMed Central

    Pino-Yanes, María; Wade, Michael S.; Pérez-Méndez, Lina; Kittles, Rick A.; Wang, Deli; Papaiahgari, Srinivas; Ford, Jean G.; Kumar, Rajesh; Garcia, Joe G. N.

    2012-01-01

    Background Asthma is a common complex condition with clear racial and ethnic differences in both prevalence and severity. Asthma consultation rates, mortality, and severe symptoms are greatly increased in African descent populations of developed countries. African ancestry has been associated with asthma, total serum IgE and lower pulmonary function in African-admixed populations. To replicate previous findings, here we aimed to examine whether African ancestry was associated with asthma susceptibility in African Americans. In addition, we examined for the first time whether African ancestry was associated with asthma exacerbations. Methodology/Principal Findings After filtering for self-reported ancestry and genotype data quality, samples from 1,117 self-reported African-American individuals from New York and Baltimore (394 cases, 481 controls), and Chicago (321 cases followed for asthma exacerbations) were analyzed. Genetic ancestry was estimated based on ancestry informative markers (AIMs) selected for being highly divergent among European and West African populations (95 AIMs for New York and Baltimore, and 66 independent AIMs for Chicago). Among case-control samples, the mean African ancestry was significantly higher in asthmatics than in non-asthmatics (82.0±14.0% vs. 77.8±18.1%, mean difference 4.2% [95% confidence interval (CI):2.0–6.4], p<0.0001). This association remained significant after adjusting for potential confounders (odds ratio: 4.55, 95% CI: 1.69–12.29, p = 0.003). African ancestry failed to show an association with asthma exacerbations (p = 0.965) using a model based on longitudinal data of the number of exacerbations followed over 1.5 years. Conclusions/Significance These data replicate previous findings indicating that African ancestry constitutes a risk factor for asthma and suggest that elevated asthma rates in African Americans can be partially attributed to African genetic ancestry. PMID:22235241

  6. Ecological observations on an East African bat community

    USGS Publications Warehouse

    O'Shea, Thomas J.; Vaughan, Terry A.

    1980-01-01

    The structure and ecology of bat faunas is a subject of interest to mammalogists (Findley, 1976; Wilson, 1973). Syntopic African bat communities, however, have received little study in comparison with neotropical faunas (cf. Fleming et al., 1972; LaVal and Fitch, 1977; McNab, 1971). Verschuren (1957) presented natural history information and species accounts for a localized central African bat fauna. Foraging related characteristics of a Rhodesian community have also been analyzed (Fenton, 1975; Fenton et al., 1977), but not on a seasonal basis. Other reports on African bat faunas are restricted to regional summaries (cf. Koopman, 1975 or Rosevear, 1965) and do not consider ecological aspects of a single localized community. The purpose of our study was to follow species composition, reproduction, and foraging related characteristics of an East African bat fauna over a full annual cycle.

  7. Phylogeny of African cichlid fishes as revealed by molecular markers.

    PubMed

    Mayer, W E; Tichy, H; Klein, J

    1998-06-01

    The species flocks of cichlid fish in the three great East African Lakes, Victoria, Malawi, and Tanganyika, have arisen in each lake by explosive adaptive radiation. Various questions concerning their phylogeny have not yet been answered. In particular, the identity of the ancestral founder species and the monophyletic origin of the haplochromine cichlids from the East African lakes have not been established conclusively. In the present study, we used the anonymous nuclear DNA marker DXTU1 as a step towards answering these questions. A 280 bp-fragment of the DXTU1 locus was amplified by the polymerase chain reaction from East African lacustrine species, the East African riverine cichlid species Haplochromis bloyeti, H. burtoni and H. sparsidens, and other African cichlids. Sequencing revealed several indels and substitutions that were used as cladistically informative markers to support a phylogenetic tree constructed by the neighbor-joining method. The topology, although not supported by high bootstrap values, corresponds well to the geographical distribution and previous classification of the cichlids. Markers could be defined that: (i) differentiate East African from West African cichlids; (ii) distinguish the riverine and Lake Victoria/Malawi haplochromines from Lake Tanganyika cichlids; and (iii) indicate the existence of a monophyletic Lake Victoria cichlid superflock which includes haplochromines from satellite lakes and East African rivers. In order to resolve further the relationship of East African riverine and lacustrine species, mtDNA cytochrome b and control region segments were sequenced. The mtDNA-based trees support the notion of the monophyly of the Lake Victoria superflock but are ambiguous with respect to the phylogenetic position of the Lake Malawi flock. PMID:9675872

  8. Lactase persistence alleles reveal partial East African ancestry of southern African Khoe pastoralists.

    PubMed

    Breton, Gwenna; Schlebusch, Carina M; Lombard, Marlize; Sjödin, Per; Soodyall, Himla; Jakobsson, Mattias

    2014-04-14

    The ability to digest milk into adulthood, lactase persistence (LP), as well as specific genetic variants associated with LP, is heterogeneously distributed in global populations. These variants were most likely targets of selection when some populations converted from hunter-gatherer to pastoralist or farming lifestyles. Specific LP polymorphisms are associated with particular geographic regions and populations; however, they have not been extensively studied in southern Africa. We investigate the LP-regulatory region in 267 individuals from 13 southern African populations (including descendants of hunter-gatherers, pastoralists, and agropastoralists), providing the first comprehensive study of the LP-regulatory region in a large group of southern Africans. The "East African" LP single-nucleotide polymorphism (SNP) (14010G>C) was found at high frequency (>20%) in a strict pastoralist Khoe population, the Nama of Namibia, suggesting a connection to East Africa, whereas the "European" LP SNP (13910C>T) was found in populations of mixed ancestry. Using genome-wide data from various African populations, we identify admixture (13%) in the Nama, from an Afro-Asiatic group dating to >1,300 years ago, with the remaining fraction of their genomes being from San hunter-gatherers. We also find evidence of selection around the LCT gene among Khoe-speaking groups, and the substantial frequency of the 14010C variant among the Nama is best explained by adaptation to digesting milk. These genome-local and genome-wide results support a model in which an East African group brought pastoralist practices to southern Africa and admixed with local hunter-gatherers to form the ancestors of Khoe people. PMID:24704072

  9. Understanding traditional African healing

    PubMed Central

    MOKGOBI, M.G.

    2015-01-01

    Traditional African healing has been in existence for many centuries yet many people still seem not to understand how it relates to God and religion/spirituality. Some people seem to believe that traditional healers worship the ancestors and not God. It is therefore the aim of this paper to clarify this relationship by discussing a chain of communication between the worshipers and the Almighty God. Other aspects of traditional healing namely types of traditional healers, training of traditional healers as well as the role of traditional healers in their communities are discussed. In conclusion, the services of traditional healers go far beyond the uses of herbs for physical illnesses. Traditional healers serve many roles which include but not limited to custodians of the traditional African religion and customs, educators about culture, counselors, social workers and psychologists. PMID:26594664

  10. Geomorphic Aspects of Southern African Dryland Soils

    NASA Astrophysics Data System (ADS)

    Eckardt, Frank

    2015-04-01

    Southern African drylands are host to stable land surfaces with limited denudation rates. The resulting soils manifest long term weathering processes, including leaching, collapse and precipitation of calcium carbonate as is the case in the semi-arid Kalahari. Despite the thickness of some of the Kalahari soils and sands, they are furthermore depicting a range of neotectonic land forms and processes, associated with the contemporary rifting of the southern African continent. This is particularly apparent in satellite imagery and digital elevation data that can be used to examine regional scale surface characteristics. Southern Africa is also home to significant global and regional scale dust sources, which are mostly associated with inland basins and playas. Plumes of dust emitted from playas are able to impact upon downwind soil quality. This can be observed in the both the western Makgadikgadi as well as the Central Namib gravel plain. In the Namib playa dust contributes to the accumulation of gravel plain fines, leaching and massive pedogenic gypsum accumulations. It is apparent that Southern African dryland soils are home to aeolian inputs, host extensive duricrusts and depict neotectonic movement which should be of interest to the wider earth science community.

  11. An Overview of the New FEER Smoke Emissions Product and Its Applications over Northern Sub-Saharan Africa

    NASA Astrophysics Data System (ADS)

    Ellison, L. T.; Ichoku, C. M.

    2012-12-01

    A new smoke emissions inventory is being derived by NASA's Fire Energetics and Emissions Research (FEER, http://feer.gsfc.nasa.gov/) group in conjunction with the NASA-funded interdisciplinary research project on the interactions and feedbacks between biomass burning and water cycle dynamics across the Northern Sub-Saharan African (NSSA) region. The vast amount of anthropogenic biomass burning conducted in NSSA during the dry months contributes significant amounts of gaseous and particulate emissions to the local climate system. The emissions product presented here is a result of the efforts made to utilize quantitative satellite measures of important fire and smoke variables to generate an accurate emissions product that can be used to quantify the relationship between biomass burning and regional climate impacts. This new product is based on a unique top-down approach whereby radiant energy and emission rates are related from independent yet coincident remotely sensed retrievals of fire radiative power (FRP) and aerosol optical depth (AOD) from the two active Moderate Resolution Imaging Spectroradiometer (MODIS) instruments. The algorithm produces a 1×1° global grid of coefficients of emission, Ce, that directly relate FRP to emission rates, or equivalently, fire radiative energy (FRE, the temporally integrated FRP curve) to emissions. Thus, emissions can be easily and quickly obtained in a given region by multiplying the Ce grid with FRP measurements acquired within that region. The Ce product offers the user flexibility in using any desired FRP data source, and the lag time in generating emissions is only constrained by that of obtaining FRP. The accuracy of this emissions product and its comparisons to other established emissions databases are presented here, as is a discussion of the contribution that this product will make toward accounting for climate variabilities in the NSSA region.

  12. Emigration dynamics of eastern African countries.

    PubMed

    Oucho, J O

    1995-01-01

    This examination of emigration dynamics focuses on 13 countries extending from Eritrea to Zimbabwe and Mozambique on the eastern African mainland and on 5 Indian Ocean island nations. The first part of the study looks at the temporal, spatial, and structural perspectives of emigration dynamics. Part 2 considers international migration in the region according to Appleyard's typology (permanent settlers, labor migration, refugees, and illegal migrants) with the additional category of return migration. Measurement issues in emigration dynamics are discussed in part 3, and the demographic/economic setting is the topic of part 4. The demographic factors emphasized include spatial distribution, population density, population structure, population dynamics, demographic transition, and the relationship between internal and international migration. Other major topics of this section of the study are the economic base, the human resource base, population and natural resources, the sociocultural context (emigration, chain migration, return migration, and migration linkages and networks), political factors (including human rights, minority rights and security, regional integration and economic cooperation, and the impact of structural adjustment programs), and a prediction of future emigration dynamics. It is concluded that refugee flows remain a major factor in eastern African countries but the development of human resources in the northern portion of the region indicates development of potential labor migration from this area. Data constraints have limited measurement of emigration in this region and may contribute to the seeming indifference of most eastern African countries to emigration policies. Emigration in this region has been triggered by deteriorating economic and political conditions and is expected to increase. PMID:12347007

  13. East African Rift Valley, Kenya

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This rare, cloud free view of the East African Rift Valley, Kenya (1.5N, 35.5E) shows a clear view of the Turkwell River Valley, an offshoot of the African REift System. The East African Rift is part of a vast plate fracture which extends from southern Turkey, through the Red Sea, East Africa and into Mozambique. Dark green patches of forests are seen along the rift margin and tea plantations occupy the cooler higher ground.

  14. The African American Struggle for Secondary Schooling, 1940-1980: Closing the Graduation Gap

    ERIC Educational Resources Information Center

    Rury, John L.; Hill, Shirley A.

    2011-01-01

    This is the first comprehensive account of African American secondary education in the postwar era. Drawing on quantitative datasets, as well as oral history, this compelling narrative examines how African Americans narrowed the racial gap in high school completion. The authors explore regional variations in high school attendance across the…

  15. Reexaming the Development of African American English: Evidence from Isolated Communities.

    ERIC Educational Resources Information Center

    Wolfram, Walt

    2003-01-01

    Examines several longstanding, isolated biracial sociolinguistic situations in the coastal and Appalachian regions of North Carolina: a core community of African Americans and two case studies of isolated speakers. Compares diagnostic phonological and morphosyntactic variables for speakers representing different generations of African American and…

  16. "We Don't Feel Welcome Here": African Americans and Hispanics in Metro Boston

    ERIC Educational Resources Information Center

    Louie, Josephine

    2005-01-01

    Racial discrimination is an ongoing reality in the lives of African Americans and Hispanics in Metro Boston. Although the region has experienced significant growth in racial and ethnic diversity over the past several decades, racial minority groups continue to struggle for full acceptance and equal opportunity. African Americans and Hispanics…

  17. Language Policy and Practice in the Multilingual Southern African Development Community

    ERIC Educational Resources Information Center

    Mooko, Theophilus

    2009-01-01

    This study explores the language policy and practice of the Southern African Development Community (SADC), an African regional economic organisation made up of 14 member states (Angola, Botswana, Democratic Republic of Congo, Lesotho, Madagascar, Malawi, Mauritius, Mozambique, Namibia, South Africa, Swaziland, United Republic of Tanzania, Zambia…

  18. Cultural In-Group Advantage: Emotion Recognition in African American and European American Faces and Voices

    ERIC Educational Resources Information Center

    Wickline, Virginia B.; Bailey, Wendy; Nowicki, Stephen

    2009-01-01

    The authors explored whether there were in-group advantages in emotion recognition of faces and voices by culture or geographic region. Participants were 72 African American students (33 men, 39 women), 102 European American students (30 men, 72 women), 30 African international students (16 men, 14 women), and 30 European international students…

  19. African American Fathers' Involvement in Their Children's School-Based Lives

    ERIC Educational Resources Information Center

    Abel, Yolanda

    2012-01-01

    This research investigated African American fathers' involvement in the school-based lives of their elementary-aged children using the Hoover-Dempsey and Sandler model of parent involvement and Epstein's framework of involvement. Questionnaires were administered to 101 African American males in the mid-Atlantic region of the United States.…

  20. Sequence diversity between class I MHC loci of African native and introduced Bos taurus cattle in Theileria parva endemic regions: in silico peptide binding prediction identifies distinct functional clusters.

    PubMed

    Obara, Isaiah; Nielsen, Morten; Jeschek, Marie; Nijhof, Ard; Mazzoni, Camila J; Svitek, Nicholas; Steinaa, Lucilla; Awino, Elias; Olds, Cassandra; Jabbar, Ahmed; Clausen, Peter-Henning; Bishop, Richard P

    2016-05-01

    There is strong evidence that the immunity induced by live vaccination for control of the protozoan parasite Theileria parva is mediated by class I MHC-restricted CD8(+) T cells directed against the schizont stage of the parasite that infects bovine lymphocytes. The functional competency of class I MHC genes is dependent on the presence of codons specifying certain critical amino acid residues that line the peptide binding groove. Compared with European Bos taurus in which class I MHC allelic polymorphisms have been examined extensively, published data on class I MHC transcripts in African taurines in T. parva endemic areas is very limited. We utilized the multiplexing capabilities of 454 pyrosequencing to make an initial assessment of class I MHC allelic diversity in a population of Ankole cattle. We also typed a population of exotic Holstein cattle from an African ranch for class I MHC and investigated the extent, if any, that their peptide-binding motifs overlapped with those of Ankole cattle. We report the identification of 18 novel allelic sequences in Ankole cattle and provide evidence of positive selection for sequence diversity, including in residues that predominantly interact with peptides. In silico functional analysis resulted in peptide binding specificities that were largely distinct between the two breeds. We also demonstrate that CD8(+) T cells derived from Ankole cattle that are seropositive for T. parva do not recognize vaccine candidate antigens originally identified in Holstein and Boran (Bos indicus) cattle breeds. PMID:26852329

  1. A Teacher's Guide to African Narratives. Studies in African Literature.

    ERIC Educational Resources Information Center

    O'Brien, Sara Talis

    This guide is designed to help secondary school teachers include African literature in their classes. It furnishes English and social studies teachers with a foundation for teaching African literature by offering critical commentary on the texts themselves. A synthesis of anthropological and historical material is presented to help both teachers…

  2. African-American Sacred Music.

    ERIC Educational Resources Information Center

    Bailey, A. Peter

    1991-01-01

    The history of African-American sacred music is traced from the time of slavery to the present interest in gospel music. The religious music of African Americans is geared toward liberation themes. It is important that this music does not dilute its power through cross-over with other music forms. (SLD)

  3. Seasonal Distribution of African Savanna Fires

    NASA Technical Reports Server (NTRS)

    Cahoon, Donald R.; Stocks, Brian J.; Levine, Joel S.; Cofer, Wesley R., III; O'Neill, Katherine P.

    1992-01-01

    Savannas consist of a continuous layer of grass interspersed with scattered trees or shrubs, and cover approx. 10 million square kilometers of tropical Africa. African savanna fires, almost all resulting from human activities, may produce as much as a third of the total global emissions from biomass burning. Little is known, however, about the frequency and location of these fires, and the area burned each year. Emissions from African savanna burning are known to be transported over the mid-Atlantic, south Pacific and Indian oceans; but to study fully the transport of regional savanna burning and the seasonality of the atmospheric circulation must be considered simultaneously. Here we describe the temporal and spatial distribution of savanna fires over the entire African continent, as determined from night-time satellite imagery. We find that, contrary to expectations, most fires are left to burn uncontrolled, so that there is no strong diurnal cycle in the fire frequency. The knowledge gained from this study regarding the distribution and variability of fires will aid monitoring of the climatically important trace gases emitted from burning biomass.

  4. The East African rift system

    NASA Astrophysics Data System (ADS)

    Chorowicz, Jean

    2005-10-01

    This overview paper considers the East African rift system (EARS) as an intra-continental ridge system, comprising an axial rift. It describes the structural organization in three branches, the overall morphology, lithospheric cross-sections, the morphotectonics, the main tectonic features—with emphasis on the tension fractures—and volcanism in its relationships with the tectonics. The most characteristic features in the EARS are narrow elongate zones of thinned continental lithosphere related to asthenospheric intrusions in the upper mantle. This hidden part of the rift structure is expressed on the surface by thermal uplift of the rift shoulders. The graben valleys and basins are organized over a major failure in the lithospheric mantle, and in the crust comprise a major border fault, linked in depth to a low angle detachment fault, inducing asymmetric roll-over pattern, eventually accompanied by smaller normal faulting and tilted blocks. Considering the kinematics, divergent movements caused the continent to split along lines of preexisting lithospheric weaknesses marked by ancient tectonic patterns that focus the extensional strain. The hypothesis favored here is SE-ward relative divergent drifting of a not yet well individualized Somalian plate, a model in agreement with the existence of NW-striking transform and transfer zones. The East African rift system comprises a unique succession of graben basins linked and segmented by intracontinental transform, transfer and accommodation zones. In an attempt to make a point on the rift system evolution through time and space, it is clear that the role of plume impacts is determinant. The main phenomenon is formation of domes related to plume effect, weakening the lithosphere and, long after, failure inducing focused upper mantle thinning, asthenospheric intrusion and related thermal uplift of shoulders. The plume that had formed first at around 30 Ma was not in the Afar but likely in Lake Tana region (Ethiopia

  5. African oil plays

    SciTech Connect

    Clifford, A.J. )

    1989-09-01

    The vast continent of Africa hosts over eight sedimentary basins, covering approximately half its total area. Of these basins, only 82% have entered a mature exploration phase, 9% have had little or no exploration at all. Since oil was first discovered in Africa during the mid-1950s, old play concepts continue to bear fruit, for example in Egypt and Nigeria, while new play concepts promise to become more important, such as in Algeria, Angola, Chad, Egypt, Gabon, and Sudan. The most exciting developments of recent years in African oil exploration are: (1) the Gamba/Dentale play, onshore Gabon; (2) the Pinda play, offshore Angola; (3) the Lucula/Toca play, offshore Cabinda; (4) the Metlaoui play, offshore Libya/Tunisia; (5) the mid-Cretaceous sand play, Chad/Sudan; and (6) the TAG-I/F6 play, onshore Algeria. Examples of these plays are illustrated along with some of the more traditional oil plays. Where are the future oil plays likely to develop No doubt, the Saharan basins of Algeria and Libya will feature strongly, also the presalt of Equatorial West Africa, the Central African Rift System and, more speculatively, offshore Ethiopia and Namibia, and onshore Madagascar, Mozambique, and Tanzania.

  6. Bioenergy and African transformation.

    PubMed

    Lynd, Lee R; Sow, Mariam; Chimphango, Annie Fa; Cortez, Luis Ab; Brito Cruz, Carlos H; Elmissiry, Mosad; Laser, Mark; Mayaki, Ibrahim A; Moraes, Marcia Afd; Nogueira, Luiz Ah; Wolfaardt, Gideon M; Woods, Jeremy; van Zyl, Willem H

    2015-01-01

    Among the world's continents, Africa has the highest incidence of food insecurity and poverty and the highest rates of population growth. Yet Africa also has the most arable land, the lowest crop yields, and by far the most plentiful land resources relative to energy demand. It is thus of interest to examine the potential of expanded modern bioenergy production in Africa. Here we consider bioenergy as an enabler for development, and provide an overview of modern bioenergy technologies with a comment on application in an Africa context. Experience with bioenergy in Africa offers evidence of social benefits and also some important lessons. In Brazil, social development, agricultural development and food security, and bioenergy development have been synergistic rather than antagonistic. Realizing similar success in African countries will require clear vision, good governance, and adaptation of technologies, knowledge, and business models to myriad local circumstances. Strategies for integrated production of food crops, livestock, and bioenergy are potentially attractive and offer an alternative to an agricultural model featuring specialized land use. If done thoughtfully, there is considerable evidence that food security and economic development in Africa can be addressed more effectively with modern bioenergy than without it. Modern bioenergy can be an agent of African transformation, with potential social benefits accruing to multiple sectors and extending well beyond energy supply per se. Potential negative impacts also cut across sectors. Thus, institutionally inclusive multi-sector legislative structures will be more effective at maximizing the social benefits of bioenergy compared to institutionally exclusive, single-sector structures. PMID:25709714

  7. Mantle support of the East African Rift System

    NASA Astrophysics Data System (ADS)

    Lin, S.; van Keken, P. E.; Brandenburg, J. P.; Furman, T.; Bryce, J.

    2007-12-01

    The African Superplume is a region of slow seismic wave velocities in the lower mantle under southern Africa. The uplift, volcanism and rifting that defines the much of eastern and southern Africa suggest a dynamic link between lower mantle dynamics and near-surface processes affecting the African plate. The dynamic link between the lower mantle and the surface, and the structure and dynamics of the upper mantle below the East African Rift System (EARS) remain unclear. As part of a comprehensive geochemical and numerical investigation of basaltic magmatism in the EARS we have modeled the interaction between putative upper mantle plumes and the rifting continental lithosphere. The modeling provides dynamically tested scenarios that explain the observed episodes of Cenozoic volcanism. Results from recent models that provided an explanation for the present day distribution of volcanism (Lin et al., EPSL, 237, 2005) suggest two plumes below Afar and Tanzania whose uplift is influenced by lithospheric topography. In new 3D modeling we provide improved quantification of the mantle involvement in generating EARS volcanism as constrained by the timing of uplift and regional volcanism. The time scales of episodicity of the volcanism observed at Turkana (related to the Tanzania-Kenya plume) since 45 Ma can be explained by deep- seated time-dependent plume activity. We suggest that this time-dependence is due to thermochemical interactions of dense recycled oceanic crust in the thermally hot regions in the African superplume region (Lin and Van Keken, Nature, 436, 2005).

  8. Human demographic history: refining the recent African origin model.

    PubMed

    Excoffier, Laurent

    2002-12-01

    Recent studies of large portions of the human genome support a recent origin of modern humans from an African stock after a bottleneck of moderate size followed by a range expansion out of Africa. Under this simple scenario, patterns of molecular diversity suggest that balancing selection could be more prevalent than positive selection in coding regions. PMID:12433581

  9. Aerosol interactions with African/Atlantic climate dynamics

    NASA Astrophysics Data System (ADS)

    Hosseinpour, F.; Wilcox, E. M.

    2014-07-01

    Mechanistic relationships exist between variability of dust in the oceanic Saharan air layer (OSAL) and transient changes in the dynamics of Western Africa and the tropical Atlantic Ocean. This study provides evidence of possible interactions between dust in the OSAL region and African easterly jet-African easterly wave (AEJ-AEW) system in the climatology of boreal summer, when easterly wave activity peaks. Synoptic-scale changes in instability and precipitation in the African/Atlantic intertropical convergence zone are correlated with enhanced aerosol optical depth (AOD) in the OSAL region in response to anomalous 3D overturning circulations and upstream/downstream thermal anomalies at above and below the mean-AEJ level. Upstream and downstream anomalies are referred to the daily thermal/dynamical changes over the West African monsoon region and the Eastern Atlantic Ocean, respectively. Our hypothesis is that AOD in the OSAL is positively correlated with the downstream AEWs and negatively correlated with the upstream waves from climatological perspective. The similarity between the 3D pattern of thermal/dynamical anomalies correlated with dust outbreaks and those of AEWs provides a mechanism for dust radiative heating in the atmosphere to reinforce AEW activity. We proposed that the interactions of OSAL dust with regional climate mainly occur through coupling of dust with the AEWs.

  10. Southern African AIDS Training Programme.

    PubMed

    Dafoe, G H

    1994-01-01

    The Canadian Public Health Association (CPHA) with the Canadian International Development Agency (CIDA), in a little over 2 years, have established a Southern African AIDS Training Programme (SAT) that is effective in developing community-based responses to acquired immunodeficiency syndrome (AIDS). Based in Harare, Zimbabwe, the program provides financial assistance, training, monitoring, and advice and information to 120 project partners. The average grant size is $40,000. In a second phase of the project, SAT will attempt to meet the requests of its partners for more services. Currently, to meet needs for rapid, responsive training, and novel approaches to skill building, SAT has developed a collaborative nongovernmental organization (NGO) initiative, "The School Without Walls". This program identifies and amplifies what has worked effectively for organizations and programs. Other similar organizations and programs learn from these experiences. Site visits, apprenticeships, mentor organizations, and skills-building based on shared problem-diagnosis and resolution are some of the techniques employed. A draft report of the CIDA midterm external evaluation of SAT recommends renewal of the program, resourcing of the program to meet its regional responsibilities, and adoption of "The School Without Walls" as a central strategy for southern Africa. PMID:8180923

  11. Quiet time enhancements over African latitudes

    NASA Astrophysics Data System (ADS)

    Orford, Nicola; Katamzi, Zama; Buresova, Dalia

    2016-07-01

    F2 layer disturbances not related to geomagnetic activity are known as quiet time enhancements (QTEs). The phenomenon of QTEs has not yet been studied over African latitudes. We therefore explore the occurrence of QTEs over Africa in order to expand our knowledge on the behaviour of the ionosphere over this region. Several GPS stations in the middle to equatorial latitudes, during the solar minimum (2009) and near solar maximum (2013), are used. This data was examined for possible trends in variation with solar cycle, season and latitude as well as time of commencement of enhancements. Over the southern mid-latitude region of Africa we have observed that the QTEs are more likely to commence during the night in both solar minimum and maximum, however a slightly larger portion of daytime commencements during solar minimum than during solar maximum were observed. The total number of enhancements for the solar minimum period appears greater than during solar maximum. A seasonal trend is seen with the maximum number of enhancements occurring in summer during solar minimum and in winter during solar maximum. We explore further whether these trends are mirrored or different at low latitude/equatorial African regions.

  12. Assimilation Differences among Africans in America.

    ERIC Educational Resources Information Center

    Dodoo, F. Nii-Amoo

    1997-01-01

    Census data (1990) indicate that male African immigrants earn more than their Caribbean-born counterparts or native-born African Americans, but controlling for relevant earnings-related endowments erases the African advantage and elevates Caribbean earnings above those of the other groups. Also, African (but not Caribbean) university degree…

  13. Successfully Educating Our African-American Students

    ERIC Educational Resources Information Center

    Moncree-Moffett, Kareem

    2013-01-01

    The purpose of this empirical study was to explore the lived experiences of African American retired female teachers who have prior experience with educating urban African American students in public schools. Also explored are the experiences of active African American female teachers of urban African American students and comparisons are…

  14. Negro, Black, Black African, African Caribbean, African American or what? Labelling African origin populations in the health arena in the 21st century.

    PubMed

    Agyemang, Charles; Bhopal, Raj; Bruijnzeels, Marc

    2005-12-01

    Broad terms such as Black, African, or Black African are entrenched in scientific writings although there is considerable diversity within African descent populations and such terms may be both offensive and inaccurate. This paper outlines the heterogeneity within African populations, and discusses the strengths and limitations of the term Black and related labels from epidemiological and public health perspectives in Europe and the USA. This paper calls for debate on appropriate terminologies for African descent populations and concludes with the proposals that (1) describing the population under consideration is of paramount importance (2) the word African origin or simply African is an appropriate and necessary prefix for an ethnic label, for example, African Caribbean or African Kenyan or African Surinamese (3) documents should define the ethnic labels (4) the label Black should be phased out except when used in political contexts. PMID:16286485

  15. African swine fever.

    PubMed

    Penrith, Mary-Louise

    2009-03-01

    African swine fever (ASF) is a devastating haemorrhagic fever of pigs that causes up to 100% mortality, for which there is no vaccine. It is caused by a unique DNA virus that is maintained in an ancient cycle between warthogs and argasid ticks, making it the only known DNA arbovirus. ASF has a high potential for transboundary spread, and has twice been transported from Africa to other continents--Europe and subsequently the Caribbean and Brazil (1957, 1959) and the Caucasus (2007). It is also a devastating constraint for pig production in Africa. Research at Onderstepoort Veterinary Institute has made and is making important contributions to knowledge of this disease, focusing on the cycle in warthogs and tampans and transmission from that cycle to domestic pigs, resistance to its effects in domestic pigs, and the molecular genetic characterisation and epidemiology of the virus. PMID:19967933

  16. The African Millennium Villages

    PubMed Central

    Sanchez, Pedro; Palm, Cheryl; Sachs, Jeffrey; Denning, Glenn; Flor, Rafael; Harawa, Rebbie; Jama, Bashir; Kiflemariam, Tsegazeab; Konecky, Bronwen; Kozar, Raffaela; Lelerai, Eliud; Malik, Alia; Modi, Vijay; Mutuo, Patrick; Niang, Amadou; Okoth, Herine; Place, Frank; Sachs, Sonia Ehrlich; Said, Amir; Siriri, David; Teklehaimanot, Awash; Wang, Karen; Wangila, Justine; Zamba, Colleen

    2007-01-01

    We describe the concept, strategy, and initial results of the Millennium Villages Project and implications regarding sustainability and scalability. Our underlying hypothesis is that the interacting crises of agriculture, health, and infrastructure in rural Africa can be overcome through targeted public-sector investments to raise rural productivity and, thereby, to increased private-sector saving and investments. This is carried out by empowering impoverished communities with science-based interventions. Seventy-eight Millennium Villages have been initiated in 12 sites in 10 African countries, each representing a major agroecological zone. In early results, the research villages in Kenya, Ethiopia, and Malawi have reduced malaria prevalence, met caloric requirements, generated crop surpluses, enabled school feeding programs, and provided cash earnings for farm families. PMID:17942701

  17. [West African childbirth traditions].

    PubMed

    Hallgren, R

    1983-11-01

    Religious and medical practices are steeped in the traditions of West African culture vis-a-vis childbirth. It is customary for delivery to occur with the woman squatting on the ground surrounded by sisters and female relatives, some of whom function as midwives. Midwives get paid only if delivery is successful. A stool is also often used in childbirth. The name given to a child in the Yoruba tribe in Nigeria has to refer to the circumstances of the individual's birth. The contact with the earth (as in the squatting position) has religious overtones--it indicates the fecundity of the earth, and the mother's contact with it. Infertility is considered the greatest tragedy in traditional African society. In Senegal, a childless woman pays a fertile one a certain sum in return for bearing her a child who would be raised as her own (this tradition is not unlike surrogate motherhood in Western countries). Men are never present at birth; however, in urban settings this practice is changing. The burial of the placenta and umbilical cord is thought to restore the woman's fertility and help heal her womb. This practice was even recorded in 19th century Sweden harkening back to heathen times. In Ghana, an infertile woman urinates on the ground where the placenta is buried in the belief that her fertility will be restored. The birth of twins is regarded as a great blessing, and as a sign of fertility; however, the inability of the mother to breast-feed both twins may result in the death of the weaker child. The harmony of nature, animals, and human beings is paramount in traditional West Africa religion and life, and undoubtedly Western culture could learn from some of these beliefs. PMID:6558064

  18. The African Genome Variation Project shapes medical genetics in Africa

    PubMed Central

    Gurdasani, Deepti; Carstensen, Tommy; Tekola-Ayele, Fasil; Pagani, Luca; Tachmazidou, Ioanna; Hatzikotoulas, Konstantinos; Karthikeyan, Savita; Iles, Louise; Pollard, Martin O.; Choudhury, Ananyo; Ritchie, Graham R. S.; Xue, Yali; Asimit, Jennifer; Nsubuga, Rebecca N.; Young, Elizabeth H.; Pomilla, Cristina; Kivinen, Katja; Rockett, Kirk; Kamali, Anatoli; Doumatey, Ayo P.; Asiki, Gershim; Seeley, Janet; Sisay-Joof, Fatoumatta; Jallow, Muminatou; Tollman, Stephen; Mekonnen, Ephrem; Ekong, Rosemary; Oljira, Tamiru; Bradman, Neil; Bojang, Kalifa; Ramsay, Michele; Adeyemo, Adebowale; Bekele, Endashaw; Motala, Ayesha; Norris, Shane A.; Pirie, Fraser; Kaleebu, Pontiano; Kwiatkowski, Dominic; Tyler-Smith, Chris; Rotimi, Charles; Zeggini, Eleftheria; Sandhu, Manjinder S.

    2014-01-01

    Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterisation of African genetic diversity is needed. The African Genome Variation Project (AGVP) provides a resource to help design, implement and interpret genomic studies in sub-Saharan Africa (SSA) and worldwide. The AGVP represents dense genotypes from 1,481 and whole genome sequences (WGS) from 320 individuals across SSA. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across SSA. We identify new loci under selection, including for malaria and hypertension. We show that modern imputation panels can identify association signals at highly differentiated loci across populations in SSA. Using WGS, we show further improvement in imputation accuracy supporting efforts for large-scale sequencing of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa, showing for the first time that such designs are feasible. PMID:25470054

  19. Triangulating the provenance of African elephants using mitochondrial DNA

    PubMed Central

    Ishida, Yasuko; Georgiadis, Nicholas J; Hondo, Tomoko; Roca, Alfred L

    2013-01-01

    African elephant mitochondrial (mt) DNA follows a distinctive evolutionary trajectory. As females do not migrate between elephant herds, mtDNA exhibits low geographic dispersal. We therefore examined the effectiveness of mtDNA for assigning the provenance of African elephants (or their ivory). For 653 savanna and forest elephants from 22 localities in 13 countries, 4258 bp of mtDNA was sequenced. We detected eight mtDNA subclades, of which seven had regionally restricted distributions. Among 108 unique haplotypes identified, 72% were found at only one locality and 84% were country specific, while 44% of individuals carried a haplotype detected only at their sampling locality. We combined 316 bp of our control region sequences with those generated by previous trans-national surveys of African elephants. Among 101 unique control region haplotypes detected in African elephants across 81 locations in 22 countries, 62% were present in only a single country. Applying our mtDNA results to a previous microsatellite-based assignment study would improve estimates of the provenance of elephants in 115 of 122 mis-assigned cases. Nuclear partitioning followed species boundaries and not mtDNA subclade boundaries. For taxa such as elephants in which nuclear and mtDNA markers differ in phylogeography, combining the two markers can triangulate the origins of confiscated wildlife products. PMID:23798975

  20. Early African Hominids: Pedagogic Patterns.

    ERIC Educational Resources Information Center

    Newman, James L.

    1984-01-01

    By studying early African hominids, students can learn about the interactive testing and creative aspects of scientific thinking and sharpen their geographical skills. It is impossible to study this topic without giving prominence to space and time. (RM)

  1. African easterly wave energetics on intraseasonal timescales

    NASA Astrophysics Data System (ADS)

    Alaka, Ghassan J., Jr.

    African easterly waves (AEWs) are synoptic-scale eddies that dominate North African weather in boreal summer. AEWs propagate westward with a maximum amplitude near 700 hPa and a period of 2.5-6-days. AEWs and associated perturbation kinetic energy (PKE) exhibit significant intraseasonal variability in tropical North Africa during boreal summer, which directly impacts local agriculture and tropical cyclogenesis. This study performs a comprehensive analysis of the 30-90-day variability of AEWs and associated energetics using both reanalysis data and model output. Specifically, the PKE and perturbation available potential energy (PAPE) budgets are used to understand the factors that contribute to PKE maxima in West Africa and the extent to which these surges of AEW activity are modulated by the Madden-Julian oscillation (MJO). The role of the MJO in the intraseasonal variability of AEWs is assessed by comparing PKE sources as a function of an MJO index and a local 30-90-day West African PKE index. Since East Africa is an initiation zone for AEW activity and is modulated by the MJO, the relationship between this region and West Africa is a primary focus in this study. The intraseasonal variability of AEW energetics is first investigated in reanalysis products. While reanalysis data depicts a similar evolution of 30-90-day PKE anomalies in both the MJO and a local PKE index, the MJO index describes only a small (yet still significant) fraction of the local 30-90-day variance. In boreal summers with more significant MJO days, the correlation between the two indices is higher. Baroclinic energy conversions are important for the initiation of 30-90-day West African PKE events east of Lake Chad. In West Africa, both barotropic and baroclinic energy conversions maintain positive PKE anomalies before they propagate into the Atlantic. The primary role of diabatic heating is to destroy PAPE in a negative feedback to baroclinic energy conversions in West Africa. More frequent

  2. Duke Engineering explores huge African Power Project

    SciTech Connect

    Newman, P.

    1994-10-14

    Duke Engineering & Services and the African Republic of Uganda have entered into a memorandum of understanding to explore the feasibility of installing one or more hydropower plants along the Nile River and building a 2,000 mile transmission line through southern Africa. The project`s participants say they envision a southern African electricity grid connecting all countries in the region. A team comprised of officials from DE&S, Edlow and SAD-ELEC will conduct a six-month, two-part study on the feasibility of linking the existing grid system in the region. The first part of the study will look at the feasibility of installing one or more independent hydropower plants along the Nile and other rivers in Uganda. The second part will explore the design, construction and operation of a transmission system to interconnect Uganda, through neighboring countries to the south and east, to the Republic of South Africa. The site for the proposed hydroelectric plant will determine the route of the transmission line.

  3. Crustal thinning between the Ethiopian and East African Plateaus from modeling Rayleigh wave dispersion

    SciTech Connect

    Benoit, M H; Nyblade, A A; Pasyanos, M E

    2006-01-17

    The East African and Ethiopian Plateaus have long been recognized to be part of a much larger topographic anomaly on the African Plate called the African Superswell. One of the few places within the African Superswell that exhibit elevations of less than 1 km is southeastern Sudan and northern Kenya, an area containing both Mesozoic and Cenozoic rift basins. Crustal structure and uppermost mantle velocities are investigated in this area by modeling Rayleigh wave dispersion. Modeling results indicate an average crustal thickness of 25 {+-} 5 km, some 10-15 km thinner than the crust beneath the adjacent East African and Ethiopian Plateaus. The low elevations can therefore be readily attributed to an isostatic response from crustal thinning. Low Sn velocities of 4.1-4.3 km/s also characterize this region.

  4. Archaean Crustal Growth, Proterozoic Terrane Amalgamation and the Pan-African Orogeny, as Recorded in the NE African Sedimentary Record.

    NASA Astrophysics Data System (ADS)

    Najman, Y.; Fielding, L.; Millar, I.; Butterworth, P.; Andò, S.; Padoan, M.; Barfod, D. N.; Kneller, B. C.

    2015-12-01

    The cratons of Central Africa are formed of various blocks of Archaean and Palaeoproterozoic crust, flanked or truncated by Palaeoproterozoic to Mesoproterozoic orogenic belts. The geology of east Africa has largely been shaped by the events of the Pan-African Orogeny when east and west Gondwana collided to form 'Greater Gondwana' at the end of the Neoproterozoic. The Pan-African orogeny in NE Africa involved the collision of Archaean cratons and the Saharan Metacraton with the Arabian Nubian Shield, a terrane comprising Neoproterozoic juvenile oceanic island arcs. Phanerozoic cover sedimentary rocks, eroded from the Pan-African orogenies, blanket much of NE Africa. Detrital data from these Phanerozoic cover sedimentary rocks, and modern rivers draining both the cover the basement, provide a wealth of information on basement evolution, of particular relevance for regions where the basement itself is poorly exposed due to ancient or modern sedimentary cover. From samples collected in Uganda, Ethiopia, Sudan and Egypt, we provide combined U-Pb and Hf-isotope zircon, U-Pb rutile and Ar-Ar mica datasets, heavy mineral analyses, and bulk trace element data, from Archaean basement, Phanerozoic cover and modern river sediment from the Nile and its tributaries to document the evolution of the North African crust. The data document early crust-forming events in the Congo Craton and Sahara Metacraton, phased development of the Arabian Nubian Shield culminating in the Neoproterozoic assembly of Gondwana during the Pan African Orogeny, and the orogen's subsequent erosion, with deposition of voluminous Phanerozoic cover.

  5. Determinants of Human Capital Formation and Economic Growth of African Countries

    ERIC Educational Resources Information Center

    Oketch, Moses O.

    2006-01-01

    Rapid economic growth and improving living standards have benefited almost all regions of the world since the industrial revolution. Africa stands out as one regional exception. While several factors such as civil wars and rampant corruption have been associated with poor economic performance of the African region in the international community,…

  6. Community among African American Students on Small, Predominantly White Campuses: The Unforeseen "Minority within a Minority" Experience

    ERIC Educational Resources Information Center

    Journal of American College Health, 2005

    2005-01-01

    Sixteen African American students participated in semi-structured, open-ended interviews about their experiences at small, predominantly white colleges in the Appalachian region. Two main themes emerged from the interviews: community among minorities and minority within a minority. The students described community among African Americans on campus…

  7. Community among African American Students on Small, Predominantly White Campuses: The Unforeseen "Minority within a Minority" Experience.

    ERIC Educational Resources Information Center

    Littleton, Robert A.

    2003-01-01

    Describes the experiences of 16 African American students who attended four small, predominantly White colleges in the Southern Appalachian region of the United States. The African American community at these small colleges can sometimes be an unforeseen cultural experience especially for Black male and female nonathletes. Qualitative methodology…

  8. 77 FR 70727 - Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition to List the African...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-27

    ... significant long-term African lion population declines. (4) Information on the correlation between climate change and African lion population dynamics, including, but not limited to: (a) Climate change... indirectly through changes in regional climate; and (b) Quantitative research on the relationship of...

  9. Investing Money to Spur Intellectual Capital? The Role of Public-Private Partnerships in African Higher Education

    ERIC Educational Resources Information Center

    Observatory on Borderless Higher Education, 2010

    2010-01-01

    The Association of Universities and Colleges of Canada (AUCC), an organisation representing 95 Canadian higher education institutions, is partnering with the Association of African Universities (AAU), to strengthen African universities' relationships with regional industry. Under a new project financially supported by the Canadian International…

  10. The African Pediatric Fellowship Program: Training in Africa for Africans.

    PubMed

    Wilmshurst, Jo M; Morrow, Brenda; du Preez, Avril; Githanga, David; Kennedy, Neil; Zar, Heather J

    2016-01-01

    Africa has a significant burden of childhood disease, with relatively few skilled health care professionals. The African Paediatric Fellowship Programme was developed by the Department of Pediatrics and Child Health at the University of Cape Town to provide relevant training for African child health professionals, by Africans, within Africa. Trainees identified by partner academic institutions spend 6 months to 2 years training in the Department of Pediatrics and allied disciplines. They then return to their home institution to build practice, training, research, and advocacy. From 2008 to 2015, 73 physicians have completed or are completing training in general pediatrics or a pediatric subspecialty. At 1 year posttraining, 98% to 100% are practicing back in their home institution. The impact of the returning fellows is evident from their practice interventions, research collaborations, and positions as stakeholders who can change health care policies. Thirty-three centers in 13 African countries are partners with the program, and the program template is now followed by other partner sites in Africa. Increasing and retaining the skills pool of African child health specialists is building a network of motivated, highly skilled clinicians who are equipped to advance child health in Africa. PMID:26659458

  11. East African Rift

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Places where the earth's crust has formed deep fissures and the plates have begun to move apart develop rift structures in which elongate blocks have subsided relative to the blocks on either side. The East African Rift is a world-famous example of such rifting. It is characterized by 1) topographic deep valleys in the rift zone, 2) sheer escarpments along the faulted walls of the rift zone, 3) a chain of lakes within the rift, most of the lakes highly saline due to evaporation in the hot temperatures characteristic of climates near the equator, 4) voluminous amounts of volcanic rocks that have flowed from faults along the sides of the rift, and 5) volcanic cones where magma flow was most intense. This example in Kenya displays most of these features near Lake Begoria.

    The image was acquired December 18, 2002, covers an area of 40.5 x 32 km, and is located at 0.1 degrees north latitude, 36.1 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  12. An African ethic for nursing?

    PubMed

    Haegert, S

    2000-11-01

    This article derives from a doctoral thesis in which a particular discourse was used as a 'paradigm case'. From this discourse an ethic set within a South African culture arose. Using many cultural 'voices' to aid the understanding of this narrative, the ethic shows that one can build on both a 'justice' and a 'care' ethic. With further development based on African culture one can take the ethic of care deeper and reveal 'layers of understanding'. Care, together with compassion, forms the foundation of morality. Nursing ethics has followed particular western moral philosophers. Often nursing ethics has been taught along the lines of Kohlberg's theory of morality, with its emphasis on rules, rights, duties and general obligations. These principles were universalistic, masculine and noncontextual. However, there is a new ethical movement among Thomist philosophers along the lines to be expounded in this article. Nurses such as Benner, Bevis, Dunlop, Fry and Gadow--to name but a few--have welcomed the concept of an 'ethic of care'. Gilligan's work gave a feminist view and situated ethics in the everyday aspects of responsiveness, responsibility, context and concern. Shutte's search for a 'philosophy for Africa' has resulted in finding similarities in Setiloane and in Senghor with those of Thomist philosophers. Using this African philosophy and a research participant's narrative, an African ethic evolves out of the African proverb: 'A person is a person through other persons', or its alternative rendering: 'I am because we are: we are because I am.' This hermeneutic narrative reveals 'the way affect imbues activity with ethical meaning' within the context of a black nursing sister in a rural South African hospital. It expands upon the above proverb and incorporates the South African constitutional idea of 'Ubuntu' (compassion and justice or humanness). PMID:11221391

  13. Removal of Escherichia coli and Faecal Coliforms from Surface Water and Groundwater by Household Water Treatment Devices/Systems: A Sustainable Solution for Improving Water Quality in Rural Communities of the Southern African Development Community Region

    PubMed Central

    Mwabi, Jocelyne K.; Mamba, Bhekie B.; Momba, Maggy N. B.

    2012-01-01

    There is significant evidence that household water treatment devices/systems (HWTS) are capable of dramatically improving microbially contaminated water quality. The purpose of this study was to examine five filters [(biosand filter-standard (BSF-S); biosand filter-zeolite (BSF-Z); bucket filter (BF); ceramic candle filter (CCF); and silver-impregnated porous pot (SIPP)] and evaluate their ability to improve the quality of drinking water at the household level. These HWTS were manufactured in the workshop of the Tshwane University of Technology and evaluated for efficiency to remove turbidity, faecal coliforms and Escherichia coli from multiple water source samples, using standard methods. The flow rates ranged from 0.05 L/h to 2.49 L/h for SIPP, 1 L/h to 4 L/h for CCF, 0.81 L/h to 6.84 L/h for BSF-S, 1.74 L/h to 19.2 L/h and 106.5 L/h to 160.5 L/h for BF The turbidity of the raw water samples ranged between 2.17 and 40.4 NTU. The average turbidity obtained after filtration ranged from 0.6 to 8 NTU (BSF-S), 1 to 4 NTU (BSF-Z), 2 to 11 NTU (BF), and from 0.6 to 7 NTU (CCF) and 0.7 to 1 NTU for SIPP. The BSF-S, BSF-Z and CCF removed 2 to 4 log10 (99% to 100%) of coliform bacteria, while the BF removed 1 to 3 log (90% to 99.9%) of these bacteria. The performance of the SIPP in removing turbidity and indicator bacteria (>5 log10, 100%) was significantly higher compared to that of the other HWTS (p < 0.05). The findings of this study indicate that the SIPP can be an effective and sustainable HWTS for the Southern African Development Community (SADC) rural communities, as it removed the total concentration of bacteria from test water, can be manufactured using locally available materials, and is easy to operate and to maintain. PMID:22470284

  14. The Southern Tropical Atlantic Region Experiment (STARE): Transport and Atmospheric Chemistry near the Equator-Atlantic (TRACE A) and Southern African Fire-Atmosphere Research Initiative (SAFARI): An introduction

    NASA Astrophysics Data System (ADS)

    Andreae, Meinrat O.; Fishman, Jack; Lindesay, Janette

    1996-10-01

    In November 1988 some 50 atmospheric scientists met at Dookie College, a small campus in the agricultural lands of Victoria, Australia, to map out the scientific goals of the International Global Atmospheric Chemistry (IGAC) Program, which was to become one of the first operational Core Projects of the International Geosphere-Biosphere Program (IGBP). They identified the tropical regions as one of the priority areas for future international, coordinated research in atmospheric chemistry because of the vast biological activity in the tropics, with a correspondingly large potential for biogenic emissions, and the rapidly growing human populations and resulting land use change in these regions. In view of the prominent role that biomass burning plays in the tropics as a source of atmospheric pollutants and of the important ecological functions of vegetation fires in the tropics, the scientists at Dookie created the Biomass Burning Experiment (BIBEX) with the goals of characterizing the fluxes of gases and aerosols from biomass burning to the global atmosphere and assessing the consequences of pyrogenic emissions on chemical and physical climate. The southern tropical Atlantic region, defined here as the region containing the Amazon basin, the tropical South Atlantic, and southern Africa, was the obvious first focus of research for this project. Large tropical forest and savanna fires had been known to occur here every year. In addition, observations from satellites and from the space shuttle had shown high levels of tropospheric ozone and carbon monoxide to be present over this region every year in the August-to-October period. Results from previous campaigns (ABLE 2A, CITE 3, DECAFE 88) also suggested a widespread impact of vegetation fires on both continents on the trace gas and aerosol content of the troposphere in this region.

  15. Interactions between Oceanic Saharan Air Layer and African Easterly Jet- African Easterly Waves System

    NASA Astrophysics Data System (ADS)

    Hosseinpour, F.; Wilcox, E. M.

    2013-12-01

    Aerosols have robust influences on multi-scale climatic systems and variability. Non-linear aerosol-cloud-climate interactions depend on many parameters such as aerosol features, regional atmospheric dynamics and variability. Although there are remarkable modeling studies indicating that aerosols induce robust modifications in cloud properties, circulations and the hydrological cycle, many of the physical and dynamical processes involving in these complex interactions between aerosols and Earth's system are still poorly understood. Better understanding the contribution of aerosols with atmospheric phenomena and their transient changes are crucial for efforts to evaluate climate predictions by next generation climate models. This study provides strong evidence of mechanistic relationships between perturbations of the oceanic Saharan air layer (OSAL) and anomalies of atmospheric circulations over the eastern tropical Atlantic/Africa. These relationships are characterized using an ensemble of daily datasets including the Modern-Era Retrospective Analysis for Research and Applications (MERRA), the Moderate Resolution Imaging Spectro-radiometer (MODIS), and the Sea-viewing Wide Field-of-View Sensor (SeaWIFS) for the boreal summer season. The study is motivated by previous results suggesting that oceanic dust-induced large-scale to meso-scale climatic adjustments. Our hypothesis is that perturbations in OSAL significantly interact with regional climate variability through African Easterly Jet- African Easterly Waves (AEJ-AEW) system. Passive/ active phases of AEWs in the northern and southern-track wave packets are associated with dipole patterns of thermal/dynamical anomalies correlated with perturbations of aerosol optical depth (AOD) in OSAL. Enhanced (suppressed) dust AOD in OSAL are significantly correlated with convective re-circulation within subsidence region of Hadley cell as well as robust mid-level dipole vorticity disturbances downstream of the AEJ core

  16. Environment, Health and Climate: Impact of African aerosols

    NASA Astrophysics Data System (ADS)

    Liousse, C.; Doumbia, T.; Assamoi, E.; Galy-Lacaux, C.; Baeza, A.; Penner, J. E.; Val, S.; Cachier, H.; Xu, L.; Criqui, P.

    2012-12-01

    Fossil fuel and biofuel emissions of particles in Africa are expected to significantly increase in the near future, particularly due to rapid growth of African cities. In addition to biomass burning emissions prevailing in these areas, air quality degradation is then expected with important consequences on population health and climatic/radiative impact. In our group, we are constructing a new integrated methodology to study the relations between emissions, air quality and their impacts. This approach includes: (1) African combustion emission characterizations; (2) joint experimental determination of aerosol chemistry from ultrafine to coarse fractions and health issues (toxicology and epidemiology). (3) integrated environmental, health and radiative modeling. In this work, we show some results illustrating our first estimates of African anthropogenic emission impacts: - a new African anthropogenic emission inventory adapted to regional specificities on traffic, biofuel and industrial emissions has been constructed for the years 2005 and 2030. Biomass burning inventories were also improved in the frame of AMMA (African Monsoon) program. - carbonaceous aerosol radiative impact in Africa has been modeled with TM5 model and Penner et al. (2011) radiative code for these inventories for 2005 and 2030 and for two scenarios of emissions : a reference scenario, with no further emission controls beyond those achieved in 2003 and a ccc* scenario including planned policies in Kyoto protocol and regulations as applied to African emission specificities. In this study we will show that enhanced heating is expected with the ccc* scenarios emissions in which the OC fraction is relatively lower than in the reference scenario. - results of short term POLCA intensive campaigns in Bamako and Dakar in terms of aerosol chemical characterization linked to specific emissions sources and their inflammatory impacts on the respiratory tract through in vitro studies. In this study, organic

  17. The African VLBI network project

    NASA Astrophysics Data System (ADS)

    Loots, Anita

    2015-01-01

    The AVN is one of the most significant vehicles through which capacity development in Africa for SKA participation will be realized. It is a forerunner to the long baseline Phase 2 component of the mid-frequency SKA. Besides the 26m HartRAO telescope in South Africa, Ghana is expected to be the first to establish a VLBI-capable telescope through conversion of a redundant 32m telecommunications system near Accra. The most widely used receivers in the EVN are L-band and C-band (5 GHz). L-band is divided into a low band around the hydrogen (HI) line frequency of 1420 MHz, and a high band covering the hydroxyl line frequencies of 1612-1720 MHz. The high band is much more commonly used for VLBI as it provides more bandwidth. For the AVN, the methanol maser line at 6668 MHz is a key target for the initial receiver and the related 12178MHz methanol maser line also seen in star-forming regions a potential future Ku-band receiver. In the potential future band around 22GHz(K-band), water masers in star-forming regions and meg-maser galaxies at 22.235 GHz are targets, as are other radio continuum sources such as AGNs. The AVN system will include 5GHz and 6.668GHz receiver systems with recommendation to partner countries that the first upgrade should be L-band receivers. The original satellite telecommunications feed horns cover 3.8 - 6.4 GHz and should work at 5 GHz and operation at 6.668 GHz for the methanol maser is yet to be verified. The first light science will be conducted in the 6.7 GHz methanol maser band. Telescopes developed for the AVN will initially join other global networks for VLBI. When at least four VLBI-capable telescopes are operational on the continent, it will be possible to initiate stand-alone AVN VLBI. Each country where an AVN telescope becomes operational will have its own single-dish observing program. Capacity building to run an observatory includes the establishment of competent core essential observatory staff in partner countries who can train

  18. African Easterly Waves and Superparameterization

    NASA Astrophysics Data System (ADS)

    McCrary, Rachel; Randall, David; Stan, Cristiana

    2013-04-01

    This study examines the dynamics of African easterly wave (AEW) in the Superparameterized Community Climate System Model (SP-CCSM). Conventional general circulation models (GCMs) have difficulty representing AEW dynamics over West Africa. One reason is that the coarse resolution of these models limits their ability to represent the multi-scale interactions between the large-scale dynamics and individual convective systems, which are important for the origin and development of AEWs. The SP-CCSM has been designed to better simulate the interactions between small-scale circulations and large-scale dynamics, by replacing the conventional parameterizations with a 2D cloud resolving model embedded within each GCM grid column. With this approach we are able to capture the interactions between clouds and the global circulation of the atmosphere. The goal of our work is to improve our understanding of the multi-scale interactions that occur between AEWs and convection over West Africa. The implementation of the superparameterization into the CCSM improves the overall representation of monsoon precipitation over West Africa. Most notably, the region of maximum precipitation is shifted from the Gulf of Guinea in CCSM (not realistic), to over the continent in SP-CCSM. The biases found in precipitation for both models are thought to be linked to anomalously warm sea surface temperatures in the Gulf of Guinea and a misrepresentation of the equatorial Atlantic cold tongue (a common problem for coupled GCMs). AEWs and their relationship with convection are also improved in the SP-CCSM. In the standard model, little to no easterly wave activity is found over West Africa, and the relationship with convection is tenuous at best. SP-CCSM on the other hand produces strong AEWs over the region that exhibit similar horizontal and vertical structures to observations. The simulated waves are also shown to be strongly coupled to convection, and results suggest that barotropic and baroclinic

  19. The genetics of East African populations: a Nilo-Saharan component in the African genetic landscape

    PubMed Central

    Dobon, Begoña; Hassan, Hisham Y.; Laayouni, Hafid; Luisi, Pierre; Ricaño-Ponce, Isis; Zhernakova, Alexandra; Wijmenga, Cisca; Tahir, Hanan; Comas, David; Netea, Mihai G.; Bertranpetit, Jaume

    2015-01-01

    East Africa is a strategic region to study human genetic diversity due to the presence of ethnically, linguistically, and geographically diverse populations. Here, we provide new insight into the genetic history of populations living in the Sudanese region of East Africa by analysing nine ethnic groups belonging to three African linguistic families: Niger-Kordofanian, Nilo-Saharan and Afro-Asiatic. A total of 500 individuals were genotyped for 200,000 single-nucleotide polymorphisms. Principal component analysis, clustering analysis using ADMIXTURE, FST statistics, and the three-population test were used to investigate the underlying genetic structure and ancestry of the different ethno-linguistic groups. Our analyses revealed a genetic component for Sudanese Nilo-Saharan speaking groups (Darfurians and part of Nuba populations) related to Nilotes of South Sudan, but not to other Sudanese populations or other sub-Saharan populations. Populations inhabiting the North of the region showed close genetic affinities with North Africa, with a component that could be remnant of North Africans before the migrations of Arabs from Arabia. In addition, we found very low genetic distances between populations in genes important for anti-malarial and anti-bacterial host defence, suggesting similar selective pressures on these genes and stressing the importance of considering functional pathways to understand the evolutionary history of populations. PMID:26017457

  20. African American Males. A Critical Link in the African American Family.

    ERIC Educational Resources Information Center

    Jones, Dionne J., Ed.

    African Americans are experiencing extreme stress in the United States, and African-American males appear to suffer the most. The chapters in this volume examine some of the issues confronting African-American men today. They include: (1) "Introduction" (Dionne J. Jones); (2) "Reaffirming Young African American Males: Mentoring and Community…

  1. African American Preschoolers' Language, Emergent Literacy Skills, and Use of African American English: A Complex Relation

    ERIC Educational Resources Information Center

    Connor, Carol McDonald; Craig, Holly K.

    2006-01-01

    Purpose: This study examined the relation between African American preschoolers' use of African American English (AAE) and their language and emergent literacy skills in an effort to better understand the perplexing and persistent difficulties many African American children experience learning to read proficiently. Method: African American…

  2. State obligations to implement African abortion laws: employing human rights in a changing legal landscape.

    PubMed

    Ngwena, Charles G

    2012-11-01

    Women in the African region are overburdened with unsafe abortion. Abortion regimes that fail to translate any given abortion rights into tangible access are partly to blame. Historically, African abortion laws have been highly restrictive. However, the post-independence era has witnessed a change toward liberalizing abortion law, even if incremental for many jurisdictions. Furthermore, Article 14 of the Protocol to the African Charter on Human and Peoples' Rights on the Rights of Women in Africa has significantly augmented the regional trend toward liberalization by recognizing abortion as a human right in given circumstances. However, states are failing to implement abortion laws. The jurisprudence that is emerging from the European Court of Human Rights and United Nations treaty bodies is a tool that can be used to render African governments accountable for failure to implement domestic abortion laws. PMID:22944215

  3. Technical Consulting: The African-American Perspective

    ERIC Educational Resources Information Center

    Whitfield, Tracy N.

    2010-01-01

    The qualitative research study explored the organizational characteristics necessary in addressing the low concentration of African American technical consultants employed in the information technology industry. Using research participants' professional experience, participants responded to a developed questionnaire. African American technical…

  4. Towards an African Philosophy of Education.

    ERIC Educational Resources Information Center

    Ocaya-Lakidi, Dent

    1980-01-01

    Compares and contrasts contemporary philosophies of education in Africa with two philosophical doctrines (naturalism and idealism). Topics discussed include value selectors, westernization, the role of missionaries in African education, critical consciousness, relevance, and African education today. (DB)

  5. African N Assessment

    NASA Astrophysics Data System (ADS)

    Bekunda, M.; Galford, G. L.; Hickman, J. E.; Palm, C.

    2011-12-01

    Africa's smallholder agricultural systems face unique challenges in planning for reducing poverty, concurrent with adaptation and mitigation to climate change. At continental level, policy seeks to promote a uniquely African Green Revolution to increase crop yields and food production, and improve local livelihoods. However, the consequences on the environment and climate are not clear; these pro-economic development measures should be linked to climate change adaptation and mitigation measures, and research is required to help achieve these policy proposals by identifying options, and testing impacts. In particular, increased nitrogen (N) inputs are essential for increasing food production in Africa, but are accompanied by inevitable increases in losses to the environment. These losses appear to be low at input levels promoted in agricultural development programs, while the increased N inputs both increase current food production and appear to reduce the vulnerability of food production to changes in climate. We present field and remote sensing evidence from Malawi that subsidizing improved seed and fertilizers increases resilience to drought without adding excess N to the environment. In Kenya, field research identified thresholds in N2O losses, where emissions are very low at fertilization rates of less than 200 kg ha-1. Village-scale models have identified potential inefficiencies in the food production process where the largest losses of reactive N occur, and which could be targeted to reduce the amount of N released to the environment. We further review some on-going research activities and progress in Africa that compare different methods of managing resources that target resilience in food production and adaptation to climate change, using nutrient N as an indicator, while evaluating the effects of these resource management practices on ecosystems and the environment.

  6. African human mtDNA phylogeography at-a-glance.

    PubMed

    Rosa, Alexandra; Brehem, António

    2011-01-01

    The mitochondrial DNA (mtDNA) genetic system has long proven to be useful for studying the demographic history of our species, since their proposed Southeast/East African origin 200 kya. Despite the weak archaeological and anthropologic records, which render a difficult understanding of early intra- continental migrations, the phylogenetic L0-L1'6 split at about 140-160 kya is thought to represent also an early sub-structuring of small and isolated communities in South and East Africa. Regional variation accumulated over the following millennia, with L2 and L3 lineages arising in Central and East Africa 100-75 kya. Their sub-Saharan dispersal not later than 60 kya, largely overwhelmed the L0'1 distribution, nowadays limited to South African Khoisan and Central African Pygmies. Cyclic expansions and retractions of the equatorial forest between 40 kya and the "Last Glacial Aridity Maximum" were able to reduce the genetic diversity of modern humans. Surviving regional-specific lineages have emerged from the Sahelian refuge areas, repopulating the region and contributing to the overall West African genetic similarity. Particular L1- L3 lineages mirror the substantial population growth made possible by moister and warmer conditions of the Sahara's Wet Phase and the adoption of agriculture and iron smelting techniques. The diffusion of the farming expertise from a Central African source towards South Africa was mediated by the Bantu people 3 kya. The strong impact of their gene flow almost erased the pre-existent maternal pool. Non-L mtDNAs testify for Eurasian lineages that have enriched the African maternal pool at different timeframes: i) Near and Middle Eastern influences in Upper Palaeolithic, probably link to the spread of Afro-Asiatic languages; ii) particular lineages from West Eurasia around or after the glacial period; iii) post-glacial mtDNA signatures from the Franco-Cantabrian refugia, that have crossed the Strait of Gibraltar and iv) Eurasian lineages

  7. The African Cultural Astronomy Project

    NASA Astrophysics Data System (ADS)

    Urama, Johnson O.; Holbrook, Jarita C.

    2011-06-01

    Indigenous, endogenous, traditional, or cultural astronomy focuses on the many ways that people and cultures interact with celestial bodies. In most parts of Africa, there is very little or no awareness about modern astronomy. However, like ancient people everywhere, Africans wondered at the sky and struggled to make sense of it. The African Cultural Astronomy Project aims to unearth the body of traditional knowledge of astronomy possessed by peoples of the different ethnic groups in Africa and to consider scientific interpretations when appropriate for cosmogonies and ancient astronomical practices. Regardless of scientific validity, every scientist can relate to the process of making observations and creating theoretical mechanisms for explaining what is observed. Through linking the traditional and the scientific, it is believed that this would be used to create awareness and interest in astronomy in most parts of Africa. This paper discusses the vision, challenges and prospects of the African Cultural Astronomy Project in her quest to popularize astronomy in Africa.

  8. Plio-pleistocene African climate

    SciTech Connect

    deMenocal, P.B.

    1995-10-06

    Marine records of African climate variability document a shift toward more arid conditions after 2.8 million years ago (Ma), evidently resulting from remote forcing by cold North Atlantic sea-surface temperatures associated with the onset of Northern Hemisphere glacial cycles. African climate before 2.8 Ma was regulated by low-latitude insolation forcing of monsoonal climate due to Earth orbital precession. Major steps in the evolution of African hominids and other vertebrates are coincident with shifts to more arid, open conditions near 2.8 Ma, 1.7 Ma, and 1.0 Ma, suggesting that some Pliocene (Plio)-Pleistocene speciation events may have been climatically mediated. 65 refs., 6 figs.

  9. Plio-Pleistocene African Climate

    NASA Astrophysics Data System (ADS)

    Demenocal, Peter B.

    1995-10-01

    Marine records of African climate variability document a shift toward more arid conditions after 2.8 million years ago (Ma), evidently resulting from remote forcing by cold North Atlantic sea-surface temperatures associated with the onset of Northern Hemisphere glacial cycles. African climate before 2.8 Ma was regulated by low-latitude insolation forcing of monsoonal climate due to Earth orbital precession. Major steps in the evolution of African hominids and other vertebrates are coincident with shifts to more arid, open conditions near 2.8 Ma, 1.7 Ma, and 1.0 Ma, suggesting that some Pliocene (Plio)-Pleistocene speciation events may have been climatically mediated.

  10. The Education of African-Americans.

    ERIC Educational Resources Information Center

    Willie, Charles V., Ed.; And Others

    The 17 papers in this volume are products of a study group on the education of African Americans that was part of a national project, "The Assessment of the Status of African-Americans." The volume takes a comprehensive look at the education of African Americans, specifically early childhood through postsecondary education, and relevant public…

  11. An Introduction to West African Literature.

    ERIC Educational Resources Information Center

    Taiwo, Oladele

    Intended to provide help for those interested in studying West African literature, this book is divided into three parts. Part One provides background information: the various African oral traditions are discussed, related to the way of life of the people, and examined for the extent to which they form the basis of present West African literary…

  12. Engaging African Americans in Smoking Cessation Programs

    ERIC Educational Resources Information Center

    Wallen, Jacqueline; Randolph, Suzanne; Carter-Pokras, Olivia; Feldman, Robert; Kanamori-Nishimura, Mariano

    2014-01-01

    Background: African Americans are disproportionately exposed to and targeted by prosmoking advertisements, particularly menthol cigarette ads. Though African Americans begin smoking later than whites, they are less likely to quit smoking than whites. Purpose: This study was designed to explore African American smoking cessation attitudes,…

  13. Freedom Road: Adult Education of African Americans.

    ERIC Educational Resources Information Center

    Peterson, Elizabeth A., Ed.

    This book contains six chapters by various authors about the history of African Americans' contributions and participation in adult education. The book reports on how some African American leaders saw the connection between education and the eventual freedom or uplift of the African American people. Following a foreword (Phyllis M. Cunningham) and…

  14. A Scale To Assess African American Acculturation.

    ERIC Educational Resources Information Center

    Snowden, Lonnie R.; Hines, Alice M.

    1999-01-01

    Investigated an acculturation scale designed for use in the African-American population. Responses from more than 900 African Americans generally indicate an African-American orientation within the sample, although there are notable variations on all 10 scale items. Discusses evidence for scale reliability and validity. (SLD)

  15. Towards a Norm in South African Englishes.

    ERIC Educational Resources Information Center

    van der Walt, Johann L.; van Rooy, Bertus

    2002-01-01

    Investigates the perception and application of the norm in South African English with specific reference to Black South African English. Hypothesizes that South African English is in the hibernation and expansion phase. Three sets of data are presented and analyzed. (Author/VWL)

  16. African Heritage Curriculum Materials. Teacher's Manual.

    ERIC Educational Resources Information Center

    Museum of African Art, Washington, DC.

    This guide for secondary teachers focuses on sub-Saharan (Black) African history and culture. Although the guide is intended to be used in conjunction with the audiovisual materials on African heritage produced by the Museum of African Art, it can also be used as a source of background reading for teachers and as a guide to additional…

  17. Admixture mapping of lung cancer in 1812 African-Americans

    PubMed Central

    Schwartz, Ann G.; Wenzlaff, Angela S.; Bock, Cathryn H.; Ruterbusch, Julie J.; Chen, Wei; Cote, Michele L.; Artis, Amanda S.; Van Dyke, Alison L.; Land, Susan J.; Harris, Curtis C.; Pine, Sharon R.; Spitz, Margaret R.; Amos, Christopher I.; Levin, Albert M.; McKeigue, Paul M.

    2011-01-01

    Lung cancer continues to be the leading cause of cancer death in the USA and the best example of a cancer with undisputed evidence of environmental risk. However, a genetic contribution to lung cancer has also been demonstrated by studies of familial aggregation, family-based linkage, candidate gene studies and most recently genome-wide association studies (GWAS). The African-American population has been underrepresented in these genetic studies and has patterns of cigarette use and linkage disequilibrium that differ from patterns in other populations. Therefore, studies in African-Americans can provide complementary data to localize lung cancer susceptibility genes and explore smoking dependence-related genes. We used admixture mapping to further characterize genetic risk of lung cancer in a series of 837 African-American lung cancer cases and 975 African-American controls genotyped at 1344 ancestry informative single-nucleotide polymorphisms. Both case-only and case–control analyses were conducted using ADMIXMAP adjusted for age, sex, pack-years of smoking, family history of lung cancer, history of emphysema and study site. In case-only analyses, excess European ancestry was observed over a wide region on chromosome 1 with the largest excess seen at rs6587361 for non-small-cell lung cancer (NSCLC) (Z-score = −4.33; P = 1.5 × 10−5) and for women with NSCLC (Z-score = −4.82; P = 1.4 × 10−6). Excess African ancestry was also observed on chromosome 3q with a peak Z-score of 3.33 (P = 0.0009) at rs181696 among ever smokers with NSCLC. These results add to the findings from the GWAS in Caucasian populations and suggest novel regions of interest. PMID:21115650

  18. Investigating the Impacts of Surface Temperature Anomalies due to Burned Area Albedo in Northern sub-Saharan Africa

    NASA Astrophysics Data System (ADS)

    Gabbert, T.; Matsui, T.; Capehart, W. J.; Ichoku, C. M.; Gatebe, C. K.

    2015-12-01

    The northern Sub-Saharan African region (NSSA) is an area of intense focus due to periodic severe droughts that have dire consequences on the growing population, which relies mostly on rain fed agriculture for its food supply. This region's weather and hydrologic cycle are very complex and are dependent on the West African Monsoon. Different regional processes affect the West African Monsoon cycle and variability. One of the areas of current investigation is the water cycle response to the variability of land surface characteristics. Land surface characteristics are often altered in NSSA due to agricultural practices, grazing, and the fires that occur during the dry season. To better understand the effects of biomass burning on the hydrologic cycle of the sub-Saharan environment, an interdisciplinary team sponsored by NASA is analyzing potential feedback mechanisms due to the fires. As part of this research, this study focuses on the effects of land surface changes, particularly albedo and skin temperature, that are influenced by biomass burning. Surface temperature anomalies can influence the initiation of convective rainfall and surface albedo is linked to the absorption of solar radiation. To capture the effects of fire perturbations on the land surface, NASA's Unified Weather and Research Forecasting (NU-WRF) model coupled with NASA's Land Information System (LIS) is being used to simulate burned area surface albedo inducing surface temperature anomalies and other potential effects to environmental processes. Preliminary sensitivity results suggest an altered surface radiation budget, regional warming of the surface temperature, slight increase in average rainfall, and a change in precipitation locations.

  19. Recommendations for Control of East African Sleeping Sickness in Uganda

    PubMed Central

    Kotlyar, Simon

    2010-01-01

    East African sleeping sickness, caused by Trypanosoma brucei rhodesiense, is prominent in Uganda and poses a serious public health challenge in the region. This publication attempts to provide key components for designing a strategy for a nationwide initiative to provide insecticide-treatment of the animal reservoir to control T. b. rhodesiense. The contents of this article will focus on insecticide-based vector control strategies, monitoring and evaluation framework, and knowledge gaps required for future initiatives. PMID:20300417

  20. Nasal aperture shape evaluation between black and white South Africans.

    PubMed

    McDowell, Jennifer L; L'Abbé, Ericka N; Kenyhercz, Michael W

    2012-10-10

    The purpose of this study was to combine morphoscopic and metric analyses to assess variation in nasal aperture size and shape of black and white South Africans. Thirteen landmarks were digitized from the bony nasal region of 152 crania using an electromechanic instrument for geometric morphometric (general procrustes analysis) and craniometric analyses. Elliptical Fourier analysis was used to assess shape of the nasal aperture via outlines applied through photographs. Both principal component and discriminant function analyses were applied to these statistical methods. Black South Africans were classified 95-96% correctly and white South Africans were classified 91-94% correctly. In a four-way analysis of sex and ancestry, classification accuracy ranged from 56 to 70%. Most misclassifications were between the sexes within each group which suggests an absence of sexual dimorphism. This study found that there is quantifiable variation in shape of the nasal aperture between black and white South African groups using all three statistical methods. In forensic application, standard craniometrics can be used to accurately classify an unknown person. PMID:22727267

  1. The African Genome Variation Project shapes medical genetics in Africa.

    PubMed

    Gurdasani, Deepti; Carstensen, Tommy; Tekola-Ayele, Fasil; Pagani, Luca; Tachmazidou, Ioanna; Hatzikotoulas, Konstantinos; Karthikeyan, Savita; Iles, Louise; Pollard, Martin O; Choudhury, Ananyo; Ritchie, Graham R S; Xue, Yali; Asimit, Jennifer; Nsubuga, Rebecca N; Young, Elizabeth H; Pomilla, Cristina; Kivinen, Katja; Rockett, Kirk; Kamali, Anatoli; Doumatey, Ayo P; Asiki, Gershim; Seeley, Janet; Sisay-Joof, Fatoumatta; Jallow, Muminatou; Tollman, Stephen; Mekonnen, Ephrem; Ekong, Rosemary; Oljira, Tamiru; Bradman, Neil; Bojang, Kalifa; Ramsay, Michele; Adeyemo, Adebowale; Bekele, Endashaw; Motala, Ayesha; Norris, Shane A; Pirie, Fraser; Kaleebu, Pontiano; Kwiatkowski, Dominic; Tyler-Smith, Chris; Rotimi, Charles; Zeggini, Eleftheria; Sandhu, Manjinder S

    2015-01-15

    Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterization of African genetic diversity is needed. The African Genome Variation Project provides a resource with which to design, implement and interpret genomic studies in sub-Saharan Africa and worldwide. The African Genome Variation Project represents dense genotypes from 1,481 individuals and whole-genome sequences from 320 individuals across sub-Saharan Africa. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across sub-Saharan Africa. We identify new loci under selection, including loci related to malaria susceptibility and hypertension. We show that modern imputation panels (sets of reference genotypes from which unobserved or missing genotypes in study sets can be inferred) can identify association signals at highly differentiated loci across populations in sub-Saharan Africa. Using whole-genome sequencing, we demonstrate further improvements in imputation accuracy, strengthening the case for large-scale sequencing efforts of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa. PMID:25470054

  2. The African Genome Variation Project shapes medical genetics in Africa

    NASA Astrophysics Data System (ADS)

    Gurdasani, Deepti; Carstensen, Tommy; Tekola-Ayele, Fasil; Pagani, Luca; Tachmazidou, Ioanna; Hatzikotoulas, Konstantinos; Karthikeyan, Savita; Iles, Louise; Pollard, Martin O.; Choudhury, Ananyo; Ritchie, Graham R. S.; Xue, Yali; Asimit, Jennifer; Nsubuga, Rebecca N.; Young, Elizabeth H.; Pomilla, Cristina; Kivinen, Katja; Rockett, Kirk; Kamali, Anatoli; Doumatey, Ayo P.; Asiki, Gershim; Seeley, Janet; Sisay-Joof, Fatoumatta; Jallow, Muminatou; Tollman, Stephen; Mekonnen, Ephrem; Ekong, Rosemary; Oljira, Tamiru; Bradman, Neil; Bojang, Kalifa; Ramsay, Michele; Adeyemo, Adebowale; Bekele, Endashaw; Motala, Ayesha; Norris, Shane A.; Pirie, Fraser; Kaleebu, Pontiano; Kwiatkowski, Dominic; Tyler-Smith, Chris; Rotimi, Charles; Zeggini, Eleftheria; Sandhu, Manjinder S.

    2015-01-01

    Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterization of African genetic diversity is needed. The African Genome Variation Project provides a resource with which to design, implement and interpret genomic studies in sub-Saharan Africa and worldwide. The African Genome Variation Project represents dense genotypes from 1,481 individuals and whole-genome sequences from 320 individuals across sub-Saharan Africa. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across sub-Saharan Africa. We identify new loci under selection, including loci related to malaria susceptibility and hypertension. We show that modern imputation panels (sets of reference genotypes from which unobserved or missing genotypes in study sets can be inferred) can identify association signals at highly differentiated loci across populations in sub-Saharan Africa. Using whole-genome sequencing, we demonstrate further improvements in imputation accuracy, strengthening the case for large-scale sequencing efforts of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa.

  3. Genetic moderation of child maltreatment effects on depression and internalizing symptoms by serotonin transporter linked polymorphic region (5-HTTLPR), brain-derived neurotrophic factor (BDNF), norepinephrine transporter (NET), and corticotropin releasing hormone receptor 1 (CRHR1) genes in African American children.

    PubMed

    Cicchetti, Dante; Rogosch, Fred A

    2014-11-01

    Genetic moderation of the effects of child maltreatment on depression and internalizing symptoms was investigated in a sample of low-income maltreated and nonmaltreated African American children (N = 1,096). Lifetime child maltreatment experiences were independently coded from Child Protective Services records and maternal report. Child depression and internalizing problems were assessed in the context of a summer research camp by self-report on the Children's Depression Inventory and adult counselor report on the Teacher Report Form. DNA was obtained from buccal cell or saliva samples and genotyped for polymorphisms of the following genes: serotonin transporter linked polymorphic region (5-HTTLPR), brain-derived neurotrophic factor (BDNF), norepinephrine transporter, and corticotropin releasing hormone receptor 1. Analyses of covariance with age and gender as covariates were conducted, with maltreatment status and respective polymorphism as main effects and their Gene × Environment (G × E) interactions. Maltreatment consistently was associated with higher Children's Depression Inventory and Teacher Report Form symptoms. The results for child self-report symptoms indicated a G × E interaction for BDNF and maltreatment. In addition, BDNF and triallelic 5-HTTLPR interacted with child maltreatment in a G × G × E interaction. Analyses for counselor report of child anxiety/depression symptoms on the Teacher Report Form indicated moderation of child maltreatment effects by triallelic 5-HTTLPR. These effects were elaborated based on variation in developmental timing of maltreatment experiences. Norepinephrine transporter was found to further moderate the G × E interaction of 5-HTTLPR and maltreatment status, revealing a G × G × E interaction. This G × G × E was extended by consideration of variation in maltreatment subtype experiences. Finally, G × G × E effects were observed for the co-action of BDNF and the corticotropin releasing hormone receptor 1

  4. African Animals at Large

    ERIC Educational Resources Information Center

    Lamanna, Stacy H.

    2007-01-01

    Africa is so rich with ancient cultures, crafts, and traditions; a source of artists' inspirations and their works of art. A vast array of Africa's tribes and regions produce their own art specific to each tribe's culture. Masks and sculptures are two of the most common types of art produced. In addition to Africa's art, the terrain is home to…

  5. African-American Children's Stories.

    ERIC Educational Resources Information Center

    Nichols, Patricia C.

    Examination of representative stories told by black American children of West African descent in South Carolina shows that specific cultural motifs have been preserved in the oral tradition of black communities. Typical stories are tales of the supernatural, such as the Hag story about mortals who shed their skin at night to do evil deeds.…

  6. African American Men in College

    ERIC Educational Resources Information Center

    Cuyjet, Michael J., Ed.

    2006-01-01

    This book is a much-needed resource that includes examples of real-world programs and activities to enhance academic success in the college environment for African American men. The examples are collected from a variety of institutions across the country. With contributions from leading practitioners and scholars in the field, this book explores…

  7. Vitamin D and African Americans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vitamin D insufficiency is more prevalent among African Americans than other Americans and, in North America, most young, healthy blacks do not achieve optimal 25-hydroxyvitamin D [25(OH)D] concentrations at any time of the year. This is primarily due to the fact that pigmentation reduces vitamin D...

  8. Classic African American Children's Literature

    ERIC Educational Resources Information Center

    McNair, Jonda C.

    2010-01-01

    The purpose of this article is to assert that there are classic African American children's books and to identify a sampling of them. The author presents multiple definitions of the term classic based on the responses of children's literature experts and relevant scholarship. Next, the manner in which data were collected and analyzed in regard to…

  9. An ImmunoChip study of multiple sclerosis risk in African Americans

    PubMed Central

    Isobe, Noriko; Madireddy, Lohith; Khankhanian, Pouya; Matsushita, Takuya; Caillier, Stacy J.; Moré, Jayaji M.; Gourraud, Pierre-Antoine; McCauley, Jacob L.; Beecham, Ashley H.; Piccio, Laura; Herbert, Joseph; Khan, Omar; Cohen, Jeffrey; Stone, Lael; Santaniello, Adam; Cree, Bruce A. C.; Onengut-Gumuscu, Suna; Rich, Stephen S.; Hauser, Stephen L.; Sawcer, Stephen

    2015-01-01

    The aims of this study were: (i) to determine to what degree multiple sclerosis-associated loci discovered in European populations also influence susceptibility in African Americans; (ii) to assess the extent to which the unique linkage disequilibrium patterns in African Americans can contribute to localizing the functionally relevant regions or genes; and (iii) to search for novel African American multiple sclerosis-associated loci. Using the ImmunoChip custom array we genotyped 803 African American cases with multiple sclerosis and 1516 African American control subjects at 130 135 autosomal single nucleotide polymorphisms. We conducted association analysis with rigorous adjustments for population stratification and admixture. Of the 110 non-major histocompatibility complex multiple sclerosis-associated variants identified in Europeans, 96 passed stringent quality control in our African American data set and of these, >70% (69) showed over-representation of the same allele amongst cases, including 21 with nominally significant evidence for association (one-tailed test P < 0.05). At a further eight loci we found nominally significant association with an alternate correlated risk-tagging single nucleotide polymorphism from the same region. Outside the regions known to be associated in Europeans, we found seven potentially associated novel candidate multiple sclerosis variants (P < 10−4), one of which (rs2702180) also showed nominally significant evidence for association (one-tailed test P = 0.034) in an independent second cohort of 620 African American cases and 1565 control subjects. However, none of these novel associations reached genome-wide significance (combined P = 6.3 × 10−5). Our data demonstrate substantial overlap between African American and European multiple sclerosis variants, indicating common genetic contributions to multiple sclerosis risk. PMID:25818868

  10. The status of African participation in the international heliophysical year (IHY)

    NASA Astrophysics Data System (ADS)

    Rabiu, Babatunde

    This paper assesses the participation of Africa in the ongoing International Heliophysical Year (IHY). IHY fosters ties between traditional/cosmic geophysics and astronomy. Astronomical Telescopes, Atmospheric Weather Electromagnetic System for Observation Modeling and Education AWESOME, Magnetic Data Acquisition System MAGDAS, Scintillation Network Decision Aid SCINDA, AMMA GPS and IGS GPS research facilities are the IHY intervention facilities already installed in African countries. The facilities are being well utilized and coordinated. National Organising Committees are being formed in individual member nations and the African Regional Committee is being strengthening towards the sensitization of the member countries and ultimate actualization of the goals of the International Cooperation program. Three continental IHY workshops have been held so far in Africa with participants drawn from several African states. The African IHY summer school has been scheduled for the last quarter of 2008. We describe the outreach activities across African axis during the 2006 total solar eclipse sponsored by IHY. Capacity building and technological transfer are part of the spin-off being derived from IHY. IHY is capable of providing a perfect bridge between north and south. African scientists and research institutes are already benefiting from the IHY planned international collaboration and cooperation. IHY is fostering strong intra-continental partnerships amongst African scientists.

  11. The flight physiology of reproductives of Africanized, European, and hybrid honeybees (Apis mellifera).

    PubMed

    Harrison, Jon F; Taylor, Orley R; Hall, H Glenn

    2005-01-01

    Neotropical African honeybees (Apis mellifera scutellata), in the process of spreading throughout tropical and subtropical regions of the Americas, hybridize with and mostly replace European honeybees (primarily Apis mellifera mellifera and Apis mellifera ligustica). To help understand this process, we studied the effect of lineage (African, European, or hybrid) on the flight physiology of honeybee reproductives. Flight metabolic rates were higher in queens and drones of African lineage than in European or hybrid bees, as has been previously found for foraging workers. These differences were associated with higher thorax/body mass ratios and higher thorax-specific metabolic rates in African lineage bees. Queens were reared in common colonies, so these metabolic and morphological differences are likely to be genetic in origin. African drones had higher wing beat frequencies and thorax temperatures than European or hybrid bees. Hybrids were intermediate for many parameters, but hybrid queen mass-specific flight metabolic rates were low relative to Africans and were nonlinearly affected by the proportion of African lineage, consistent with some negative heterosis for this trait. PMID:15778935

  12. Developing anatomical terms in an African language.

    PubMed

    Madzimbamuto, Farai Daniel

    2012-03-01

    Clinical and technical information imparted in most African languages involves inexact terminology and code switching, so it lacks the explanatory power characterised by the English language. African languages are absent in the tertiary science education environment and forums where African scientists could present scientific material in the medium of African languages. This limits the development of African languages in the scientific domain. There has recently been a trend in several African languages to develop and intellectualise them, especially in the field of medical sciences. The ChiShona language is used to explore the ability of an African language to develop new terminology, to name the vertebral skeleton and describe it scientifically. It uses word compounding to demonstrate terminology development. ChiShona has similarities with several hundred other Bantu languages in East, Central and Southern Africa. Advancing this language can promote similar developments in others, making them more explanatory for the lay public and health professionals. PMID:22380900

  13. Molecular phylogenetics reveal multiple tertiary vicariance origins of the African rain forest trees

    PubMed Central

    Couvreur, Thomas LP; Chatrou, Lars W; Sosef, Marc SM; Richardson, James E

    2008-01-01

    Background Tropical rain forests are the most diverse terrestrial ecosystems on the planet. How this diversity evolved remains largely unexplained. In Africa, rain forests are situated in two geographically isolated regions: the West-Central Guineo-Congolian region and the coastal and montane regions of East Africa. These regions have strong floristic affinities with each other, suggesting a former connection via an Eocene pan-African rain forest. High levels of endemism observed in both regions have been hypothesized to be the result of either 1) a single break-up followed by a long isolation or 2) multiple fragmentation and reconnection since the Oligocene. To test these hypotheses the evolutionary history of endemic taxa within a rain forest restricted African lineage of the plant family Annonaceae was studied. Molecular phylogenies and divergence dates were estimated using a Bayesian relaxed uncorrelated molecular clock assumption accounting for both calibration and phylogenetic uncertainties. Results Our results provide strong evidence that East African endemic lineages of Annonaceae have multiple origins dated to significantly different times spanning the Oligocene and Miocene epochs. Moreover, these successive origins (c. 33, 16 and 8 million years – Myr) coincide with known periods of aridification and geological activity in Africa that would have recurrently isolated the Guineo-Congolian rain forest from the East African one. All East African taxa were found to have diversified prior to Pleistocene times. Conclusion Molecular phylogenetic dating analyses of this large pan-African clade of Annonaceae unravels an interesting pattern of diversification for rain forest restricted trees co-occurring in West/Central and East African rain forests. Our results suggest that repeated reconnections between the West/Central and East African rain forest blocks allowed for biotic exchange while the break-ups induced speciation via vicariance, enhancing the levels of

  14. Model, Proxy and Isotopic Perspectives on the East African Humid Period

    NASA Technical Reports Server (NTRS)

    Tierney, Jessica E.; Lewis, Sophie C.; Cook, Benjamin I.; LeGrande, Allegra N.; Schmidt, Gavin A.

    2011-01-01

    Both North and East Africa experienced more humid conditions during the early and mid-Holocene epoch (11,000-5000yr BP; 11-5 ka) relative to today. The North African Humid Period has been a major focus of paleoclimatic study, and represents a response of the hydrological cycle to the increase in boreal summer insolation and associated ocean, atmosphere and land surface feedbacks. Meanwhile, the mechanisms that caused the coeval East African Humid Period are poorly understood. Here, we use results from isotopeenabled coupled climate modeling experiments to investigate the cause of the East African Humid Period. The modeling results are interpreted alongside proxy records of both water balance and the isotopic composition of rainfall. Our simulations show that the orbitally-induced increase in dry season precipitation and the subsequent reduction in precipitation seasonality can explain the East African Humid Period, and this scenario agrees well with regional lake level and pollen paleoclimate data. Changes in zonal moisture flux from both the Atlantic and Indian Ocean account for the simulated increase in precipitation from June through November. Isotopic paleoclimate data and simulated changes in moisture source demonstrate that the western East African Rift Valley in particular experienced more humid conditions due to the influx of Atlantic moisture and enhanced convergence along the Congo Air Boundary. Our study demonstrates that zonal changes in moisture advection are an important determinant of climate variability in the East African region.

  15. Observed Oceanic and Terrestrial Drivers of North African Climate

    NASA Astrophysics Data System (ADS)

    Yu, Y.; Notaro, M.; Wang, F.; Mao, J.; Shi, X.; Wei, Y.

    2015-12-01

    Hydrologic variability can pose a serious threat to the poverty-stricken regions of North Africa. Yet, the current understanding of oceanic versus terrestrial drivers of North African droughts/pluvials is largely model-based, with vast disagreement among models. In order to identify the observed drivers of North African climate and develop a benchmark for model evaluations, the multivariate Generalized Equilibrium Feedback Assessment (GEFA) is applied to observations, remotely sensed data, and reanalysis products. The identified primary oceanic drivers of North African rainfall variability are the Atlantic, tropical Indian, and tropical Pacific Oceans and Mediterranean Sea. During the summer monsoon, positive tropical eastern Atlantic sea-surface temperature (SST) anomalies are associated with a southward shift of the Inter-Tropical Convergence Zone, enhanced ocean evaporation, and greater precipitable water across coastal West Africa, leading to increased West African monsoon (WAM) rainfall and decreased Sahel rainfall. During the short rains, positive SST anomalies in the western tropical Indian Ocean and negative anomalies in the eastern tropical Indian Ocean support greater easterly oceanic flow, evaporation over the western ocean, and moisture advection to East Africa, thereby enhancing rainfall. The sign, magnitude, and timing of observed vegetation forcing on rainfall vary across North Africa. The positive feedback of leaf area index (LAI) on rainfall is greatest during DJF for the Horn of Africa, while it peaks in autumn and is weakest during the summer monsoon for the Sahel. Across the WAM region, a positive LAI anomaly supports an earlier monsoon onset, increased rainfall during the pre-monsoon, and decreased rainfall during the wet season. Through unique mechanisms, positive LAI anomalies favor enhanced transpiration, precipitable water, and rainfall across the Sahel and Horn of Africa, and increased roughness, ascent, and rainfall across the WAM region

  16. A method to compute the n-dimensional solid spectral angle between vectors and its use for band selection in hyperspectral data

    NASA Astrophysics Data System (ADS)

    Tian, M.; Feng, J.; Rivard, B.; Zhao, C.

    2016-08-01

    This study presents the calculation of spectral angle beyond two endmember vectors to the n-dimensional solid spectral angle (NSSA). The calculation of the NSSA is used to characterize the local spectral shape difference among a set of endmembers, leading to a methodology for band selection based on spectral shape variations of more than two spectra. Equidistributed sequences used in the quasi-Monte Carlo method (ESMC) for numerical simulations are shown to expedite the calculation of the NSSA. We develop a band selection method using the computation of NSSA(ϑn) in the context of a sliding window. By sliding the window over all bands available for varying band intervals, the calculated solid spectral angle values can capture the similarity of the endmembers over all spectral regions available and for spectral features of varying widths. By selecting a subset of spectral bands with largest solid spectral angles, a methodology can be developed to capture the most important spectral information for the separation or mapping of endmembers. We provide an example of the merits of the NSSA-ESMC method for band selection as applied to linear spectral unmixing. Specifically, we examine the endmember abundance errors resulting from the NSSA band selection method as opposed to using the full spectral dimensionality available.

  17. Placing AMISR Instrument in the African sector: Why and How?

    NASA Astrophysics Data System (ADS)

    Yizengaw, Endawoke; Moldwin, Mark; Coster, Anthea

    2012-07-01

    Much of our understanding of this complex equatorial electrodynamics and ionospheric density distribution has been primarily based on observation from the only equatorial Jicamarca incoherent scatter radar (ISR) instrument (even though satellite observation telling us differently) which is located in the region where fairly large excursion between the geomagnetic and geographic equator is available. In the African sector, where there is currently no incoherent (or coherent) scatter radar, the geomagnetic and geodetic equators are reasonably parallel, separated by at most 10 degrees. Data from satellites (e.g. ROCSAT, C/NOFS, DMSP) have indicated that the equatorial ionosphere in the African sector responds differently than other sectors. For example, ionospheric bubbles have been observed to be much deeper and to occur more frequently in the African sector. It has also been reported that ionospheric depletions more frequently rise to higher altitudes (up to 1000+ km) in the African sector than those in other longitude sectors. However, these observations have not been confirmed, validated or studied in detail by observations from the ground due to lack of suitable ground-based instrumentation in Africa. Thus, the causes or driving mechanisms of the unique density irregularities, bubbles, and depletions in the African sector remain unresolved. To address these issues, the U.S. National Science Foundation has recently sponsored a workshop that has been held at Boston College to consider the possibility of relocating an Advanced Modular Incoherent Scatter Radar (AMISR) to Ethiopia. Adding a single ISR to the recently growing number of ground-based space science instruments in the continent, such as GPS, magnetometers, VHF, and Ionosonde, would be of significant scientific benefit. The primary purpose of this workshop was to define the science goals motivating such a move and to examine the technical and logistical issues involved. This talk will summarize the findings

  18. IHY objectives in the African ionospheric irregularities observation campaign

    NASA Astrophysics Data System (ADS)

    Yizengaw, E.; Moldwin, M. B.

    2008-05-01

    : One of many objectives of IHY is the deployment of networks of small instruments, especially closing the land-based gaps of instruments around the world. One of the regions that have been almost entirely devoid of ground-based instruments is the African continent. Such uneven distribution of ground-based instruments hinders our ability to obtain a global understanding of the equatorial ionosphere. In the African sector, for example, a continuous ground-based observation of the equatorial ionospheric irregularities is not possible due to lack of ground-based instruments, causing many fundamental questions to remain unanswered. Satellite observations indicate the equatorial ionospheric density structures in the African continent respond to space weather effects differently than do other parts of the Earth. For example, in the African equatorial region, satellite observations show that the F-region bubbles are much deeper than the bubbles observed in any other longitudinal sectors, and are very active year round compared with other regions. Observations also show that the bubbles in Africa rises to high altitude (up to 1000+ kilometers) more frequently compared with other longitudes. However, these responses have not been studied in detail by observations from the ground due to the lack of suitable ground-based instrumentation in the region. Thus, the cause of these unique density irregularities in the continent remains a mystery for the scientific community. Therefore, in order to have a better understanding, the scientific communities, using the IHY platform, are now closing the largest land-based gap in ground-based instruments such as GPS receivers and magnetometers. The instrumentation network in African is already developing rapidly with GPS receivers from SCINDA, AMMA, IGS, and AGREES and magnetometers from MAGDAS and AMBER. In addition to new scientific discoveries and advancing space science research in Africa by establishing scientific collaborations

  19. Dust-rainfall feedbacks in the West African Sahel

    NASA Astrophysics Data System (ADS)

    Hui, Wanching Jacquie; Cook, Benjamin I.; Ravi, Sujith; Fuentes, José D.; D'Odorico, Paolo

    2008-05-01

    Dust aerosols can suppress rainfall by increasing the number of cloud condensation nuclei in warm clouds and affecting the surface radiation budget and boundary layer instability. The extent to which atmospheric dust may affect precipitation yields and the hydrologic cycle in semiarid regions remains poorly understood. We investigate the relationship between dust aerosols and rainfall in the West African Sahel where the dust-rainfall feedback has been speculated to contribute to sustained droughts. We find that the amount of dust loadings is negatively correlated with rainfall values, suggesting that dust entrained in the atmosphere can significantly inhibit rainfall in this region.

  20. The UCAR Africa Initiative: Enabling African Solutions to African Needs

    NASA Astrophysics Data System (ADS)

    Pandya, R.; Bruintjes, R.; Foote, B.; Heck, S.; Hermann, S.; Hoswell, L.; Konate, M.; Kucera, P.; Laing, A.; Lamptey, B.; Moncrieff, M.; Ramamurthy, M.; Roberts, R.; Spangler, T.; Traoré, A.; Yoksas, T.; Warner, T.

    2007-12-01

    The University Corporation for Atmospheric Research (UCAR) Africa Initiative (AI) is a coordinated effort aimed at building sustainable partnerships between UCAR and African institutions in order to pursue research and applications for the benefit of the African people. The initiative is based on four fundamental operating principles, concisely summarized by the overall philosophy of enabling African solutions to African needs. The four principles are: • Collaborate with African institutions • Focus on institutional capacity building and research support • Explore science research themes critical to Africa and important for the world • Leverage the research infrastructure in UCAR to add value These principles are realized in a set of pilot activities, chosen for their high probability of short-term results and ability to set the stage for longer-term collaboration. The three pilot activities are listed below. 1. A modest radar network and data-distribution system in Mali and Burkina Faso, including a data-sharing MOU between the Mail and Burkina Faso Weather Services. 2. A partnership among UCAR, the Ghana Meteorological Agency, and the Ghana university community to develop an operational Weather Research and Forecasting (WRF) model for West Africa. The output is used by researchers and operational forecasters in Africa. Model output is also part of a demonstration project that aims to allow humanitarian agencies to share geo-referenced information in Africa via a web portal. 3. A workshop in Ouagadougou, Burkina Faso from April 2-6, 2007, with the theme Improving Lives by Understanding Weather. The workshop, co-organized with Programme SAAGA and the Commité Permanent Inter-Etats de Lutte Contre la Sécheresse dans le Sahel (CILSS), included over 80 participants from 18 countries, and produced a set of recommendations for continued collaboration. Our presentation will provide an update of these pilot activities and point to future directions. Recognizing

  1. Mitochondrial DNA diversity in the African American population.

    PubMed

    Johnson, Derek C; Shrestha, Sadeep; Wiener, Howard W; Makowsky, Robert; Kurundkar, Ashish; Wilson, Craig M; Aissani, Brahim

    2015-06-01

    Genetic polymorphism along mitochondrial DNA (mtDNA) defines population-specific signatures called mtDNA haplogroups. Estimation of mtDNA haplogroup distribution may be prone to errors, notably if the study sample is not drawn from a multicenter cohort. Here, we report on mtDNA diversity in a sample of African American individuals (n = 343) enrolled in a multicenter cohort. Sequencing of the hypervariable regions I and II of the D-loop control region showed that the most common mitochondrial variants are 73G, 146C, 150T, 152C, 189G, 16278T, and 16311C. In agreement with the published data, we observed 17 common mtDNA haplogroups: L0, L1, L1b, L1c, L2, L2a, L2b, L2c, L2e, L3, L3b, L3d, L3e, L3f, L3h, L3x, and L4. The most commonly observed haplogroup is L2a (19.8%), followed by L1b (10.2%). Overall, the observed mtDNA haplogroup distribution in our study is similar to those published for the African American and the African populations. PMID:24102597

  2. Mitochondrial DNA diversity in the African American population

    PubMed Central

    Johnson, Derek C.; Shrestha, Sadeep; Wiener, Howard W.; Makowsky, Robert; Kurundkar, Ashish; Wilson, Craig M.; Aissani, Brahim

    2014-01-01

    Genetic polymorphism along mitochondrial DNA (mtDNA) defines population-specific signatures called mtDNA haplogroups. Estimation of mtDNA haplogroup distribution may be prone to errors, notably if the study sample is not drawn from a multicenter cohort. Here, we report on mtDNA diversity in a sample of African American individuals (n = 343) enrolled in a multicenter cohort. Sequencing of the hypervariable regions I and II of the D-loop control region showed that the most common mitochondrial variants are 73G, 146C, 150T, 152C, 189G, 16278T, and 16311C. In agreement with the published data, we observed 17 common mtDNA haplogroups: L0, L1, L1b, L1c, L2, L2a, L2b, L2c, L2e, L3, L3b, L3d, L3e, L3f, L3h, L3x, and L4. The most commonly observed haplogroup is L2a (19.8%), followed by L1b (10.2%). Overall, the observed mtDNA haplogroup distribution in our study is similar to those published for the African American and the African populations. PMID:24102597

  3. The African landscape through space and time

    NASA Astrophysics Data System (ADS)

    Paul, Jonathan D.; Roberts, Gareth G.; White, Nicky

    2014-06-01

    It is generally accepted that Cenozoic epeirogeny of the African continent is moderated by convective circulation of the mantle. Nevertheless, the spatial and temporal evolution of Africa's "basin-and-swell" physiography is not well known. Here we show how continental drainage networks can be used to place broad constraints on the pattern of uplift through space and time. First, we assemble an inventory of 710 longitudinal river profiles that includes major tributaries of the 10 largest catchments. River profiles have been jointly inverted to determine the pattern of uplift rate as a function of space and time. Our inverse model assumes that shapes of river profiles are controlled by uplift rate history and modulated by erosional processes, which can be calibrated using independent geologic evidence (e.g., marine terraces, volcanism and thermochronologic data). Our results suggest that modern African topography started to develop ˜30 Myr ago when volcanic swells appeared in North and East Africa. During the last 15-20 Myr, subequatorial Africa was rapidly elevated, culminating in the appearance of three large swells that straddle southern and western coasts. Our results enable patterns of sedimentary flux at major deltas to be predicted and tested. We suggest that the evolution of drainage networks is dominated by rapid upstream advection of signals produced by a changing pattern of regional uplift. An important corollary is that, with careful independent calibration, these networks might act as useful tape recorders of otherwise inaccessible mantle processes. Finally, we note that there are substantial discrepancies between our results and published dynamic topographic predictions.

  4. African neurosurgery, the 21st-century challenge.

    PubMed

    El-Fiki, Mohamed

    2010-04-01

    Two major challenges facing African neurosurgery include quality and quantity, in both recourses and personnel. Discrepancy is noted between the two poles, namely, the north and south of the continent and the sub-Saharan area. Although reasonably advanced in the north and south, neurosurgery remains poorly distributed and has multiple deficiencies. The sub-Saharan region, where the demand is high and services are scarce, suffers from a similar lack of both qualified personnel and well-equipped neurosurgical facilities. Insufficient state funding and research facilities aggravate the situation and discourage the few well-trained African neurosurgeons to practice in their homeland. For those who do return home, cultural, social, economical, and political issues hinder their performance and hence the quality of neurosurgery delivered in Africa. Strategies for rectification of these handicaps are presented, including the need for high-standard local training and support from international organizations. PMID:20849772

  5. Multigene families in African swine fever virus: family 505.

    PubMed Central

    Rodriguez, J M; Yañez, R J; Pan, R; Rodriguez, J F; Salas, M L; Viñuela, E

    1994-01-01

    Sequencing of restriction fragment EcoRI A-SalI C of African swine fever virus has revealed the existence of a multigene family, designated family 505 because of the average number of amino acids in the proteins, composed of seven homologous and tandemly arranged genes. All the genes of family 505 are expressed during infection. Primer extension analysis showed that transcription is initiated a short distance (3 to 62 nucleotides) from the start codon of the corresponding open reading frame. The proteins of family 505 showed similarity to those of family 360 from African swine fever virus. In particular, a striking conservation of three regions at the amino terminus of the polypeptides was observed. Images PMID:8139051

  6. Building resilience to face recurring environmental crisis in African Sahel

    NASA Astrophysics Data System (ADS)

    Boyd, Emily; Cornforth, Rosalind J.; Lamb, Peter J.; Tarhule, Aondover; Lélé, M. Issa; Brouder, Alan

    2013-07-01

    The present food shortages in the Horn of Africa and the West African Sahel are affecting 31 million people. Such continuing and future crises require that people in the region adapt to an increasing and potentially irreversible global sustainability challenge. Given this situation and that short-term weather and seasonal climate forecasting have limited skill for West Africa, the Rainwatch project illustrates the value of near real-time monitoring and improved communication for the unfavourable 2011 West African monsoon, the resulting severe drought-induced humanitarian impacts continuing into 2012, and their exacerbation by flooding in 2012. Rainwatch is now coupled with a boundary organization (Africa Climate Exchange, AfClix) with the aim of integrating the expertise and actions of relevant institutions, agencies and stakeholders to broker ground-based dialogue to promote resilience in the face of recurring crisis.

  7. African aerosol and trace-gas emissions from the Central-African Bujumbura station.

    NASA Astrophysics Data System (ADS)

    Gielen, Clio; Van Roozendael, Michel; Hendrick, Francois; Pinardi, Gaia; De Smet, Isabelle; Fayt, Caroline; Hermans, Christian; Ndenzako, Eugene; Nzohabonayo, Pierre; Akimana, Rachel

    2015-04-01

    We present aerosol and trace-gas retrievals from the new Central-African measurement site of Bujumbura, where a new MAX-DOAS instrument and cimel sun photometer have been operational since late 2013. This is the first time that MAX-DOAS measurements are performed in Central Africa, which are critical to resolve the large uncertainties of satellite observations of trace gases and aerosols over this area. The Bujumbura region is a source of strong biogenic compounds and biomass burning products, and invaluable to study the export of African emissions to the Indian ocean. Using the bePRO radiative transfer tool, we retrieve aerosol optical depths (AODs) and vertical extinction profiles for aerosols and trace gases such as NO2 and HCHO. The AOD retrievals are compared to the co-located AERONET sun photometer measurements and further analysed to investigate seasonal and diurnal cycles in the observed variability or to detect biomass-burning events.For the trace gases NO2 and HCHO, the ground-based MAX-DOAS vertical columns and profiles are used for tropospheric trace-gas validation of the GOME-2 and OMI satellites. We further discuss the representativity of the site regarding satelitte comparisons and modelling efforts, given its specific orography.

  8. What Works? A Qualitative Examination of the Factors Related to the Academic Success of African American Males at a Predominantly White College in the South

    ERIC Educational Resources Information Center

    Robertson, Ray V.; Mason, Danielle

    2008-01-01

    Our study examined the factors related to the retention/academic success of African American males at a mid-sized, regional, predominantly white university in the south. The selected university has an African American male graduation rate, of approximately twenty three percent, which is thirteen percentage points below the national Black male…

  9. Intervention Induced Changes on Parenting Practices, Youth Self-Pride and Sexual Norms to Reduce HIV-Related Behaviors among Rural African American Youths

    ERIC Educational Resources Information Center

    Murry, Velma McBride; Berkel, Cady; Chen, Yi-fu; Brody, Gene H.; Gibbons, Frederick X.; Gerrard, Meg

    2011-01-01

    AIDS is the leading killer of African Americans between the ages of 25 and 44, many of whom became infected when they were teenagers or young adults. The disparity in HIV infection rate among African Americans youth residing in rural Southern regions of the United States suggests that there is an urgent need to identify ways to promote early…

  10. Brief Report: Under-Representation of African Americans in Autism Genetic Research--A Rationale for Inclusion of Subjects Representing Diverse Family Structures

    ERIC Educational Resources Information Center

    Hilton, Claudia L.; Fitzgerald, Robert T.; Jackson, Kelley M.; Maxim, Rolanda A.; Bosworth, Christopher C.; Shattuck, Paul T.; Geschwind, Daniel H.; Constantino, John N.

    2010-01-01

    African American children with autism are seriously under-represented in existing genetic registries and biomedical research studies of autism. We estimated the number of African American children with autism in the St. Louis region using CDC surveillance data and present the outcomes of a concerted effort to enroll approximately one-third of that…

  11. Identifying New Sources of African American Male Pre-Service Teachers: Creating a Path from Student-Athlete to Student-Teacher

    ERIC Educational Resources Information Center

    Byrd, David A.; Butler, Bettie Ray; Lewis, Chance W.; Bonner, Fred A., II; Rutledge, Michael; Watson, Jesse J.

    2011-01-01

    This qualitative research study examined the experiences of one African American former college athlete and two athletic department academic advisors at a BCS Division University in the Southern Region of the United States, Given the catastrophic shortage of African American male K-12 teachers, the participants of this study were interviewed to…

  12. African American Therapists Working with African American Families: An Exploration of the Strengths Perspective in Treatment

    ERIC Educational Resources Information Center

    Bell-Tolliver, Laverne; Burgess, Ruby; Brock, Linda J.

    2009-01-01

    With the exception of Hill's (1971, 1999) work, historically much of the literature on African American families has focused more on pathology than strengths. This study used interviews with 30 African American psychotherapists, self-identified as employing a strengths perspective with African American families, to investigate which strengths they…

  13. Karla Holloway to Lead African and African-American Studies at Duke University.

    ERIC Educational Resources Information Center

    Hawkins, B. Denise

    1996-01-01

    The appointment of Karla F. C. Holloway, an African American woman, as director of the Duke University (North Carolina) African American Studies program is representative of an institutional effort to stabilize the program and to recruit African American scholars to the institution, across disciplines. During Holloway's interim directorship,…

  14. A Genomic Portrait of Haplotype Diversity and Signatures of Selection in Indigenous Southern African Populations

    PubMed Central

    Chimusa, Emile R.; Meintjies, Ayton; Tchanga, Milaine; Mulder, Nicola; Seoighe, Cathal; Soodyall, Himla; Ramesar, Rajkumar

    2015-01-01

    We report a study of genome-wide, dense SNP (∼900K) and copy number polymorphism data of indigenous southern Africans. We demonstrate the genetic contribution to southern and eastern African populations, which involved admixture between indigenous San, Niger-Congo-speaking and populations of Eurasian ancestry. This finding illustrates the need to account for stratification in genome-wide association studies, and that admixture mapping would likely be a successful approach in these populations. We developed a strategy to detect the signature of selection prior to and following putative admixture events. Several genomic regions show an unusual excess of Niger-Kordofanian, and unusual deficiency of both San and Eurasian ancestry, which were considered the footprints of selection after population admixture. Several SNPs with strong allele frequency differences were observed predominantly between the admixed indigenous southern African populations, and their ancestral Eurasian populations. Interestingly, many candidate genes, which were identified within the genomic regions showing signals for selection, were associated with southern African-specific high-risk, mostly communicable diseases, such as malaria, influenza, tuberculosis, and human immunodeficiency virus/AIDs. This observation suggests a potentially important role that these genes might have played in adapting to the environment. Additionally, our analyses of haplotype structure, linkage disequilibrium, recombination, copy number variation and genome-wide admixture highlight, and support the unique position of San relative to both African and non-African populations. This study contributes to a better understanding of population ancestry and selection in south-eastern African populations; and the data and results obtained will support research into the genetic contributions to infectious as well as non-communicable diseases in the region. PMID:25811879

  15. 75 FR 2844 - African Development Foundation, Board of Directors Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-19

    ...; ] AFRICAN DEVELOPMENT FOUNDATION African Development Foundation, Board of Directors Meeting Time: Tuesday, January 26, 2010, 8:30 a.m. to 1 p.m. Place: African Development Foundation, Conference Room, 1400...

  16. 75 FR 14418 - African Development Foundation, Board of Directors Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-25

    ...; ] AFRICAN DEVELOPMENT FOUNDATION African Development Foundation, Board of Directors Meeting Time: Tuesday, April 13, 2010, 9:30 a.m. to 1 p.m. Place: African Development Foundation, Conference Room, 1400...

  17. 75 FR 45600 - African Development Foundation, Board of Directors Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-03

    ...; ] AFRICAN DEVELOPMENT FOUNDATION African Development Foundation, Board of Directors Meeting Time: Tuesday, August 17, 2010, 8:30 a.m. to 1 p.m. Place: African Development Foundation, Conference Room, 1400...

  18. Cultural aspects of African American eating patterns.

    PubMed

    Airhihenbuwa, C O; Kumanyika, S; Agurs, T D; Lowe, A; Saunders, D; Morssink, C B

    1996-09-01

    The high mortality from diet-related diseases among African Americans strongly suggests a need to adopt diets lower in total fat, saturated fat and salt and higher in fiber. However, such changes would be contrary to some traditional African American cultural practices. Focus group interviews were used to explore cultural aspects of eating patterns among low- and middle-income African Americans recruited from an urban community in Pennsylvania. In total, 21 males and 32 females, aged 13-65+ years were recruited using a networking technique. Participants identified eating practices commonly attributed to African Americans and felt that these were largely independent of socioeconomic status. They were uncertain about links between African American eating patterns and African origins but clear about influences of slavery and economic disadvantage. The perception that African American food patterns were characteristically adaptive to external conditions, suggest that, for effective dietary change in African American communities, changes in the food availability will need to precede or take place in parallel with changes recommended to individuals. Cultural attitudes about where and with whom food is eaten emerged as being equivalent in importance to attitudes about specific foods. These findings emphasize the importance of continued efforts to identify ways to increase the relevance of cultural context and meanings in dietary counseling so that health and nutrition interventions are anchored in values as perceived, in this case, by African Americans. PMID:9395569

  19. Race, health, and the African Diaspora.

    PubMed

    Spigner, Clarence

    Health inequalities exist throughout the African Diaspora and are viewed in this article as largely color-coded. In developed, developing, and undeveloped nations today, "racial" stratification is consistently reflected in an inability to provide adequate health regardless of national policy or ideology. For instance, African Americans experience less than adequate health care very similar to Blacks in Britain, in spite of each nations differing health systems. Latin America's Africana Negra communities experience poorer health similar to Blacks throughout the Caribbean. The African continent itself is arguably the poorest on earth. A common history of racism correlates with health disparities across the African Diaspora. PMID:18364304

  20. Gentle Africanized bees on an oceanic island

    PubMed Central

    Rivera-Marchand, Bert; Oskay, Devrim; Giray, Tugrul

    2012-01-01

    Oceanic islands have reduced resources and natural enemies and potentially affect life history traits of arriving organisms. Among the most spectacular invasions in the Western hemisphere is that of the Africanized honeybee. We hypothesized that in the oceanic island Puerto Rico, Africanized bees will exhibit differences from the mainland population such as for defensiveness and other linked traits. We evaluated the extent of Africanization through three typical Africanized traits: wing size, defensive behavior, and resistance to Varroa destructor mites. All sampled colonies were Africanized by maternal descent, with over 65% presence of European alleles at the S-3 nuclear locus. In two assays evaluating defense, Puerto Rican bees showed low defensiveness similar to European bees. In morphology and resistance to mites, Africanized bees from Puerto Rico are similar to other Africanized bees. In behavioral assays on mechanisms of resistance to Varroa, we directly observed that Puerto Rican Africanized bees groomed-off and bit the mites as been observed in other studies. In no other location, Africanized bees have reduced defensiveness while retaining typical traits such as wing size and mite resistance. This mosaic of traits that has resulted during the invasion of an oceanic island has implications for behavior, evolution, and agriculture. PMID:23144660

  1. Recent African origin of modern humans revealed by complete sequences of hominoid mitochondrial DNAs.

    PubMed Central

    Horai, S; Hayasaka, K; Kondo, R; Tsugane, K; Takahata, N

    1995-01-01

    We analyzed the complete mitochondrial DNA (mtDNA) sequences of three humans (African, European, and Japanese), three African apes (common and pygmy chimpanzees, and gorilla), and one orangutan in an attempt to estimate most accurately the substitution rates and divergence times of hominoid mtDNAs. Nonsynonymous substitutions and substitutions in RNA genes have accumulated with an approximately clock-like regularity. From these substitutions and under the assumption that the orangutan and African apes diverged 13 million years ago, we obtained a divergence time for humans and chimpanzees of 4.9 million years. This divergence time permitted calibration of the synonymous substitution rate (3.89 x 10(-8)/site per year). To obtain the substitution rate in the displacement (D)-loop region, we compared the three human mtDNAs and measured the relative abundance of substitutions in the D-loop region and at synonymous sites. The estimated substitution rate in the D-loop region was 7.00 x 10(-8)/site per year. Using both synonymous and D-loop substitutions, we inferred the age of the last common ancestor of the human mtDNAs as 143,000 +/- 18,000 years. The shallow ancestry of human mtDNAs, together with the observation that the African sequence is the most diverged among humans, strongly supports the recent African origin of modern humans, Homo sapiens sapiens. PMID:7530363

  2. Regional Higher Education Reform Initiatives in Africa: A Comparative Analysis with the Bologna Process

    ERIC Educational Resources Information Center

    Woldegiorgis, Emnet Tadesse; Jonck, Petronella; Goujon, Anne

    2015-01-01

    Europe's Bologna Process has been identified as a pioneering approach in regional cooperation with respect to the area of higher education. To address the challenges of African higher education, policymakers are recommending regional cooperation that uses the Bologna Process as a model. Based on these recommendations, the African Union Commission…

  3. Southern African NGOs seize the initiative.

    PubMed

    Morna, C L

    1990-11-01

    The Southern African Network of AIDS Service Organizations (SANASO) was begun at a conference in Harare, Zimbabwe in May 1990, marking the 1st local unification of Non-Governmental agencies in AIDS prevention and care. This region has about 20% of Africa's reported AIDS cases, but has seen an 8-fold increase in 2 years. The goals of the organization are to facilitate sharing of information, ideas and experiences, to promote cooperation among the NGOs, to move toward common positions on AIDS and to articulate to the rest of the world the needs of the region as regards AIDS. While the incidence ranges from 6/million in Lesotho, to 906/million in Malawi, the countries represented have varied but pressing political and economic situations making HIV infection a serious threat. Examples are economic contraction with reduced funding of health and education; rapid urbanization; wars in Angola and Mozambique, with associated sexual abuse, refugees and displaced people; and in South Africa Apartheid, unemployment, forced relocation, violence and even suspicion of the government's AIDS program. Discussions on how the NGOs in particular can help change peoples' behavior resulted in the suggestion that they involve People With AIDS (PWA), to give the disease "a face" and lessen fear and alienation. The best example of such a successful approach is the home-based care instituted by Zambia's Chikankata Salvation Army Mission Hospital. PMID:12343148

  4. Hysteresis in the Central African Rainforest

    NASA Astrophysics Data System (ADS)

    Pietsch, Stephan Alexander; Elias Bednar, Johannes; Gautam, Sishir; Petritsch, Richard; Schier, Franziska; Stanzl, Patrick

    2014-05-01

    Past climate change caused severe disturbances of the Central African rainforest belt, with forest fragmentation and re-expansion due to drier and wetter climate conditions. Besides climate, human induced forest degradation affected biodiversity, structure and carbon storage of Congo basin rainforests. Information on climatically stable, mature rainforest, unaffected by human induced disturbances, provides means of assessing the impact of forest degradation and may serve as benchmarks of carbon carrying capacity over regions with similar site and climate conditions. BioGeoChemical (BGC) ecosystem models explicitly consider the impacts of site and climate conditions and may assess benchmark levels over regions devoid of undisturbed conditions. We will present a BGC-model validation for the Western Congolian Lowland Rainforest (WCLRF) using field data from a recently confirmed forest refuge, show model - data comparisons for disturbed und undisturbed forests under different site and climate conditions as well as for sites with repeated assessment of biodiversity and standing biomass during recovery from intensive exploitation. We will present climatic thresholds for WCLRF stability, analyse the relationship between resilience, standing C-stocks and change in climate and finally provide evidence of hysteresis.

  5. Projections of 21st Century African Climate: Implications for African Savanna Fire Dynamics, Human Health and Food Security

    NASA Astrophysics Data System (ADS)

    Adegoke, J. O.

    2015-12-01

    Fire is a key agent of change in the African savannas, which are shaped through the complex interactions between trees, C4 grasses, rainfall, temperature, CO2 and fire. These fires and their emitted smoke can have numerous direct and indirect effects on the environment, water resources, air quality, and climate. For instance, veld fires in southern Africa cause large financial losses to agriculture, livestock production and forestry on an annual basis. This study contributes to our understanding of the implications of projected surface temperature evolution in Africa for fire risk, human health and agriculture over the coming decades. We use an ensemble of high-resolution regional climate model simulations of African climate for the 21st century. Regional dowscalings and recent global circulation model projections obtained for Africa indicate that African temperatures are likely to rise at 1.5 times the global rate of temperature increase in the tropics, and at almost twice the global rate of increase in the subtropics. Warming is projected to occur during the 21st century, with increases of 4-6 °C over the subtropics and 3-5 °C over the tropics plausible by the end of the century relative to present-day climate under the A2 (low mitigation) scenario. We explore the significance of the projected warming by documenting increases in projected high fire danger days and heat-wave days. General drying is projected across the continent, even for areas (e.g. tropical Africa) where an increase in rainfall is plausible. This is due to the drastic increases in temperature that are projected, which leads to drier soils (through enhanced evaporation) despite the rainfall increases. This will likely impact negatively on crop yield, particularly on the maize crop that is of crucial importance in terms of African food security.

  6. Electricity power Sector reform in the GCC region

    SciTech Connect

    Al-Asaad, Hassan K.

    2009-11-15

    The Gulf Cooperation Council interconnection will act as a gateway towards achieving regional and pan-Arab power pools, thus promoting social, economic, and environmental development and cooperation in the Middle East and North African countries. (author)

  7. Overcoming barriers to health-care access: A qualitative study among African migrants in Guangzhou, China.

    PubMed

    Lin, Lavinia; Brown, Katherine B; Hall, Brian J; Yu, Fan; Yang, Jingqi; Wang, Jason; Schrock, Joshua M; Bodomo, Adams B; Yang, Ligang; Yang, Bin; Nehl, Eric J; Tucker, Joseph D; Wong, Frank Y

    2016-10-01

    Guangzhou is China's third most populous city, and the region's burgeoning manufacturing economy has attracted many young African businessmen and entrepreneurs to the city. The aims of this study were to examine strategies that African migrants in Guangzhou have adopted in response to health-care barriers, and explore their perceptions of how to address their needs. Twenty-five semi-structured interviews and two focus groups were conducted among African migrants residing in Guangzhou, China. Facing multiple barriers to care, African migrants have adopted a number of suboptimal and unsustainable approaches to access health care. These included: using their Chinese friends or partners as interpreters, self-medicating, using personal connections to medical doctors, and travelling to home countries or countries that offer English-speaking doctors for health care. Health-care providers and health organisations in Guangzhou have not yet acquired sufficient cultural competence to address the needs of African migrants residing in the city. Introducing linguistically and culturally competent health-care services in communities concentrated with African migrants may better serve the population. With the growing international migration to China, it is essential to develop sustainable approaches to improving health-care access for international migrants, particularly those who are marginalised. PMID:26400191

  8. Establishment of baseline haematology and biochemistry parameters in wild adult African penguins (Spheniscus demersus).

    PubMed

    Parsons, Nola J; Schaefer, Adam M; van der Spuy, Stephen D; Gous, Tertius A

    2015-01-01

    There are few publications on the clinical haematology and biochemistry of African penguins (Spheniscus demersus) and these are based on captive populations. Baseline haematology and serum biochemistry parameters were analysed from 108 blood samples from wild, adult African penguins. Samples were collected from the breeding range of the African penguin in South Africa and the results were compared between breeding region and sex. The haematological parameters that were measured were: haematocrit, haemoglobin, red cell count and white cell count. The biochemical parameters that were measured were: sodium, potassium, chloride, calcium, inorganic phosphate, creatinine, cholesterol, serum glucose, uric acid, bile acid, total serum protein, albumin, aspartate transaminase and creatine kinase. All samples were serologically negative for selected avian diseases and no blood parasites were detected. No haemolysis was present in any of the analysed samples. Male African penguins were larger and heavier than females, with higher haematocrit, haemoglobin and red cell count values, but lower calcium and phosphate values. African penguins in the Eastern Cape were heavier than those in the Western Cape, with lower white cell count and globulin values and a higher albumin/globulin ratio, possibly indicating that birds are in a poorer condition in the Western Cape. Results were also compared between multiple penguin species and with African penguins in captivity. These values for healthy, wild, adult penguins can be used for future health and disease assessments. PMID:26016391

  9. Frequency and origins of hemoglobin S mutation in African-derived Brazilian populations.

    PubMed

    De Mello Auricchio, Maria Teresa Balester; Vicente, João Pedro; Meyer, Diogo; Mingroni-Netto, Regina Célia

    2007-12-01

    Africans arrived in Brazil as slaves in great numbers, mainly after 1550. Before the abolition of slavery in Brazil in 1888, many communities, called quilombos, were formed by runaway or abandoned African slaves. These communities are presently referred to as remnants of quilombos, and many are still partially genetically isolated. These remnants can be regarded as relicts of the original African genetic contribution to the Brazilian population. In this study we assessed frequencies and probable geographic origins of hemoglobin S (HBB*S) mutations in remnants of quilombo populations in the Ribeira River valley, São Paulo, Brazil, to reconstruct the history of African-derived populations in the region. We screened for HBB*S mutations in 11 quilombo populations (1,058 samples) and found HBB*S carrier frequencies that ranged from 0% to 14%. We analyzed beta-globin gene cluster haplotypes linked to the HBB*S mutation in 86 chromosomes and found the four known African haplotypes: 70 (81.4%) Bantu (Central Africa Republic), 7 (8.1%) Benin, 7 (8.1%) Senegal, and 2 (2.3%) Cameroon haplotypes. One sickle cell homozygote was Bantu/Bantu and two homozygotes had Bantu/Benin combinations. The high frequency of the sickle cell trait and the diversity of HBB*S linked haplotypes indicate that Brazilian remnants of quilombos are interesting repositories of genetic diversity present in the ancestral African populations. PMID:18494376

  10. African anthropogenic combustion emission inventory: specificities and uncertainties

    NASA Astrophysics Data System (ADS)

    Sekou, K.; Liousse, C.; Eric-michel, A.; Veronique, Y.; Thierno, D.; Roblou, L.; Toure, E. N.; Julien, B.

    2015-12-01

    Fossil fuel and biofuel emissions of gases and particles in Africa are expected to significantly increase in the near future, particularly due to the growth of African cities. In addition, African large savannah fires occur each year during the dry season, mainly for socio-economical purposes. In this study, we will present the most recent developments of African anthropogenic combustion emission inventories, stressing African specificities. (1)A regional fossil fuel and biofuel inventory for gases and particulates will be presented for Africa at a resolution of 0.25° x 0.25° from 1990 to 2012. For this purpose, the original database of Liousse et al. (2014) has been used after modification for emission factors and for updated regional fuel consumption including new emitter categories (waste burning, flaring) and new activity sectors (i.e. disaggregation of transport into sub-sectors including two wheel ). In terms of emission factors, new measured values will be presented and compared to litterature with a focus on aerosols. They result from measurement campaigns organized in the frame of DACCIWA European program for each kind of African specific anthropogenic sources in 2015, in Abidjan (Ivory Coast), Cotonou (Benin) and in Laboratoire d'Aérologie combustion chamber. Finally, a more detailed spatial distribution of emissions will be proposed at a country level to better take into account road distributions and population densities. (2) Large uncertainties still remain in biomass burning emission inventories estimates, especially over Africa between different datasets such as GFED and AMMABB. Sensitivity tests will be presented to investigate uncertainties in the emission inventories, applying methodologies used for AMMABB and GFED inventories respectively. Then, the relative importance of each sources (fossil fuel, biofuel and biomass burning inventories) on the budgets of carbon monoxide, nitrogen oxides, sulfur dioxide, black and organic carbon, and volatile

  11. Striving to be in the profession and of It: the African American experience in physical education and kinesiology.

    PubMed

    Wiggins, David K; Wiggins, Brenda P

    2011-06-01

    This study analyzes the experiences of African Americans in the physical education and kinesiology profession since the late 1850s. Using a variety of primary and secondary source material, we place special emphasis on the experiences of African American physical educators in higher education and in the American Alliance for Health, Physical Education, Recreation and Dance and its southern, regional, and state chapters. Apparent from this examination is that African Americans have experienced various forms of racially discriminatory practices in physical education and kinesiology and have found it extraordinarily difficult to assume leader ship positions in the profession and be acknowledged for their scholarly and academic accomplishments. PMID:21699112

  12. Witchcraft in Transkei Region of South African: case report.

    PubMed

    Meel, B L

    2009-03-01

    Witchcraft and witch-hunt have been practiced widely almost all over the world. It is known as magic in Europe, maleficium (wrong-doing) in Latin America, and superpower in Asia. In Africa those accused of being witches often face execution. A range of accusations are leveled against witches such as causing impotence, turning milk sour, causing disease and death.Three cases are presented here to highlight the issues related to witch craft in Transkei area. The information was given by the next of kin at the time of autopsy. All were elderly women over 50 years of age. The first was related to tuberculosis of the brother of the perpetrator the second, death of the culprit's relative and third the death of culprits brother in Johannesburg. The first and third victims were brutally chopped by axe and in the second it was a firearm injury. The case history, the type of wounds, and medico-legal aspects of death are discussed in these reports. There law related to witchcraft and their implementations to prevent such deaths are discussed. PMID:20842246

  13. Institutionalization of African traditional medicine in health care systems in Africa.

    PubMed

    Kofi-Tsekpo, Mawuli

    2004-01-01

    In recent times, the phrase " traditional medicine" has become a catchword among the peoples in all countries in Africa. This has been due partly because the use of herbal remedies has gained popularity worldwide and the exploitation of these remedies has become a multimillion industry. The term "African traditional medicine" is not synonymous with "Alternative and complimentary medicine" which is a misnomer which is sometimes used. African traditional medicine is the African indigenous system of health care and therefore cannot be an alternative. In Africa, there is an important reason why African traditional medicine has become increasingly popular. The high cost of allopathic medical health care and the expensive pharmaceutical products have become unavailable to a majority of people. Naturally, the many centuries-old alternative sources of health care have become handy, often in desperate situations. In fact, the frequently quoted statement that 85 per cent of the people in Africa use traditional medicine, is an understatement because this figure is much higher and continues to increase. At the Alma Atta Declaration of 1978, it was resolved that traditional medicine had to be incorporated in the health care systems in developing countries if the objective of the "Health for All by the Year 2000" was to be realized. Notwithstanding this strategy, African countries did not come near the objective at the end of the 20th century. Therefore, the Member States of the WHO African Region adopted a resolution in 2000 called "Promoting the role of traditional medicine in health care systems: A strategy for the African Region". This strategy provides for the institutionalization of traditional medicine in health care systems of the member states of the WHO African Region. Furthermore, the OAU (African Union) Heads of State and Government declared the period 2000 - 2010 as the African Decade on African Traditional Medicine. In addition, the Director General of the World

  14. The Nubian Complex of Dhofar, Oman: An African Middle Stone Age Industry in Southern Arabia

    PubMed Central

    Rose, Jeffrey I.; Usik, Vitaly I.; Marks, Anthony E.; Hilbert, Yamandu H.; Galletti, Christopher S.; Parton, Ash; Geiling, Jean Marie; Černý, Viktor; Morley, Mike W.; Roberts, Richard G.

    2011-01-01

    Despite the numerous studies proposing early human population expansions from Africa into Arabia during the Late Pleistocene, no archaeological sites have yet been discovered in Arabia that resemble a specific African industry, which would indicate demographic exchange across the Red Sea. Here we report the discovery of a buried site and more than 100 new surface scatters in the Dhofar region of Oman belonging to a regionally-specific African lithic industry - the late Nubian Complex - known previously only from the northeast and Horn of Africa during Marine Isotope Stage 5, ∼128,000 to 74,000 years ago. Two optically stimulated luminescence age estimates from the open-air site of Aybut Al Auwal in Oman place the Arabian Nubian Complex at ∼106,000 years ago, providing archaeological evidence for the presence of a distinct northeast African Middle Stone Age technocomplex in southern Arabia sometime in the first half of Marine Isotope Stage 5. PMID:22140561

  15. HIV-related stigma among African-American youth in the Northeast and Southeast US.

    PubMed

    Kerr, Jelani C; Valois, Robert F; Diclemente, Ralph J; Fletcher, Faith; Carey, Michael P; Romer, Daniel; Vanable, Peter A; Farber, Naomi

    2014-06-01

    HIV-related stigma inhibits optimal HIV prevention and treatment among African-Americans. Regional differences in HIV/AIDS prevalence may be related to stigma among young African-Americans. Baseline data (N = 1,606) from an HIV prevention intervention were used to investigate regional differences in HIV-related stigma and knowledge among African-American adolescents in four midsized cities in the Northeastern and Southeastern US. Analyses indicated greater HIV-related stigma among adolescents from the Southeast relative to adolescents from the Northeast (F = 22.23; p < 0.0001). Linear regression indicated a negative relationship between HIV stigma and HIV knowledge (b = -0.65; p < 0.0001). Addressing HIV/AIDS in high prevalence locales should include efforts to reduce HIV-related stigma. PMID:24402690

  16. Environmental health and African Americans.

    PubMed Central

    Walker, B

    1991-01-01

    As environmental health has taken on immensely increased significance in the prevention of disease, dysfunction, and premature death, its boundaries have been anything but stable. This instability, along with a multitude of demographic, social, and economic currents, have brought into stark relief the increasing demand for scientists who have the skills and knowledge to perform environmental risk assessment and implement effective risk management policies and services. Despite this demand far too few African Americans want, or are prepared, to pursue careers in sciences. This paper describes efforts to address this problem and suggests why such initiatives may not yield the desired results. PMID:1951793

  17. Environmental sensing by African trypanosomes.

    PubMed

    Roditi, Isabel; Schumann, Gabriela; Naguleswaran, Arunasalam

    2016-08-01

    African trypanosomes, which divide their life cycle between mammals and tsetse flies, are confronted with environments that differ widely in temperature, nutrient availability and host responses to infection. In particular, since trypanosomes cannot predict when they will be transmitted between hosts, it is vital for them to be able to sense and adapt to their milieu. Thanks to technical advances, significant progress has been made in understanding how the parasites perceive external stimuli and react to them. There is also a growing awareness that trypanosomes use a variety of mechanisms to exchange information with each other, thereby enhancing their chances of survival. PMID:27131101

  18. Improving African American Achievement in Geometry Honors

    ERIC Educational Resources Information Center

    Mims, Adrian B.

    2010-01-01

    This case study evaluated the significance of implementing an enrichment mathematics course during the summer to rising African American ninth graders entitled, "Geometry Honors Preview." In the past, 60 to 70 percent of African American students in this school district had withdrawn from Geometry Honors by the second academic quarter. This study…

  19. Heart Truth for African American Women

    MedlinePlus

    THE HEART TRUTH ® FOR AFRICAN AMERICAN WOMEN: AN ACTION PLAN When you hear the term “heart disease,” what’s your first reaction? Like many women, you may ... in four women dies of heart disease. For African American women, the risk of heart disease is especially ...

  20. A Mirror Image African American Student Reflections

    ERIC Educational Resources Information Center

    Cannon Dawson, Candice

    2012-01-01

    This dissertation is a narrative inquiry research project that focuses on the collegiate experiences of African American students at both historically black colleges and universities (HBCUs) and predominantly white institutions (PWIs). I look at how African American college students who engage in race or culturally specific activities, the degree…

  1. The African Student in the American University.

    ERIC Educational Resources Information Center

    Riley, Doris

    This paper gathers information on the values, cognition, and educational background of African students studying at universities in the United States. The section on values notes that Americans are task-oriented individualists, while Africans are primarily relationship-oriented collectivists. These values of sharing and relationship orientation…

  2. African (Black) Psychology: Issues and Synthesis.

    ERIC Educational Resources Information Center

    Baldwin, Joseph A.

    1986-01-01

    Reviews the recent attempts of Black psychologists and social scientists to formulate a conceptual-operational framework for the study of psychological phenomena as they bear on the cultural-survival conditions of Black-African people. Outlines issues and problems in the attempt to define African (Black) psychology and discusses its relation to…

  3. African American Women in Higher Education

    ERIC Educational Resources Information Center

    Zamani, Eboni M.

    2003-01-01

    African American women hold a unique position as members of two groups that have been treated in a peripheral manner by postsecondary education (Moses, 1989). Membership in both marginalized groups often makes African American women invisible in colleges and universities. Given the complex intersection of race and gender, more attention should be…

  4. Cancer and the African American Experience

    Cancer.gov

    The first plenary of the EPEC-O (Education in Palliative and End-of-Life Care for Oncology) Self-Study: Cultural Considerations When Caring for African Americans explores the many factors that lead to inequalities in cancer care outcomes for African Americans.

  5. Computer Networks and African Studies Centers.

    ERIC Educational Resources Information Center

    Kuntz, Patricia S.

    The use of electronic communication in the 12 Title VI African Studies Centers is discussed, and the networks available for their use are reviewed. It is argued that the African Studies Centers should be on the cutting edge of contemporary electronic communication and that computer networks should be a fundamental aspect of their programs. An…

  6. Reading Comprehension among African American Graduate Students

    ERIC Educational Resources Information Center

    Onwuegbuzie, Anthony J.; Mayes, Eric; Arthur, Leslie; Johnson, Joseph; Robinson, Veronica; Ashe, Shante; Elbedour, Salman; Collins, Kathleen M. T.

    2004-01-01

    A study was conducted to examine the reading comprehension performance of African American graduate students. The result showed that though the African American sample attained statistically significantly higher levels of reading comprehension than a normative sample of undergraduate students, they achieved lower levels of reading comprehension…

  7. Technology Builds Global Acceptance among African Students.

    ERIC Educational Resources Information Center

    John, Martha Tyler; John, Floyd Idwal

    This paper describes how a new university, African Nazarene University (ANU) in Kenya, used various means, including computer technology, for implementing learning goals for students from a wide variety of African countries and tribes. The paper stresses that the school, which opened in 1994 with 65 students, emphasized tolerance of differences…

  8. Genetics Home Reference: African iron overload

    MedlinePlus

    ... of a genetic condition? Genetic and Rare Diseases Information Center Frequency African iron overload is common in rural areas of central and ... more about the gene associated with African iron overload SLC40A1 Related Information What is a gene? What is a gene ...

  9. African Higher Education: An International Reference Handbook.

    ERIC Educational Resources Information Center

    Teferra, Damtew, Ed.; Altbach, Philip G., Ed.

    This book is a comprehensive survey of all aspects and dimensions of higher education in Africa. It includes a historical overview of higher education, descriptions of the higher education systems in each African country, and analyses of current and timely topics in higher education. Part 1, "Themes," contains 13 essays on trends in African higher…

  10. African American Art: A Los Angeles Legacy.

    ERIC Educational Resources Information Center

    Walker, Harriet

    This curriculum unit focuses on the importance of Los Angeles (California) as a center for African American art and shows how African American artists have developed their own styles and how critics and collectors have encouraged them. The unit consists of four lessons, each of which can stand alone or be used in conjunction with the others. It…

  11. New data on African health professionals abroad

    PubMed Central

    Clemens, Michael A; Pettersson, Gunilla

    2008-01-01

    Background The migration of doctors and nurses from Africa to developed countries has raised fears of an African medical brain drain. But empirical research on the causes and effects of the phenomenon has been hampered by a lack of systematic data on the extent of African health workers' international movements. Methods We use destination-country census data to estimate the number of African-born doctors and professional nurses working abroad in a developed country circa 2000, and compare this to the stocks of these workers in each country of origin. Results Approximately 65,000 African-born physicians and 70,000 African-born professional nurses were working overseas in a developed country in the year 2000. This represents about one fifth of African-born physicians in the world, and about one tenth of African-born professional nurses. The fraction of health professionals abroad varies enormously across African countries, from 1% to over 70% according to the occupation and country. Conclusion These numbers are the first standardized, systematic, occupation-specific measure of skilled professionals working in developed countries and born in a large number of developing countries. PMID:18186916

  12. Beyond Afrocentricism: Alternatives for African American Studies.

    ERIC Educational Resources Information Center

    Hall, Perry A.

    1991-01-01

    Discusses new directions for African-American studies curricula. Argues that the Afrocentrist perspective presents a static model that does not adequately address the dynamic interaction of Afrocentric sensibility with Western-dominated economic, cultural, and political structures. The African-American studies discipline should be conceptualized…

  13. Traditional African Religion: A Resource Unit.

    ERIC Educational Resources Information Center

    Garland, William E.

    This resource unit is based on research conducted by Lynn Mitchell and Ernest Valenzuela, experienced classroom teachers of African history and culture. The unit consists of an introduction by Mr. Garland and two major parts. Part I is an annotated bibliography of selected sources on various aspects of traditional African Religion useful in…

  14. The African American Woman. Runta (Truth).

    ERIC Educational Resources Information Center

    Jackson, Monica L.; Watson, Betty Collier, Ed.

    1989-01-01

    The African American woman has commanded widespread public attention, but popular misconceptions of her socioeconomic role and status differ sharply from her actual situation. The following basic characteristics of the contemporary African American woman, drawn from census figures, are outlined: (1) demographically, females comprise a majority of…

  15. Kunta Kinte's Struggle to be African

    ERIC Educational Resources Information Center

    Courlander, Harold

    1986-01-01

    This article reveals the differences between the character Kunta Kinte and the historical record concerning African males in the preslavery period. Kunta's non-African behaviors include displays of blind anger and rage, prudishness, and actions unknown in his Mandinka culture. These represent the many misrepresentations and ambiguities in Alex…

  16. France: Africans and the French Revolution.

    ERIC Educational Resources Information Center

    Fatunde, Tunde

    1989-01-01

    The French Revolution had profound and long-term effects for Africans, both in Africa and throughout the Western hemisphere. Revolutionary leaders not only opposed the emancipation of slaves in French territories but supported an intensified slave trade, sparking numerous rebellions. French exploitation of Africans extended well into the twentieth…

  17. African American Undergraduates and the Academic Library

    ERIC Educational Resources Information Center

    Whitmire, Ethelene

    2006-01-01

    This study examines the academic library experiences of African American undergraduates attending a research university in the Midwest. Data collection techniques included questionnaires and ethnographic observations. The results indicated that African American undergraduates are using the academic library primarily to read and to study with their…

  18. Hidden Education among African Americans during Slavery

    ERIC Educational Resources Information Center

    Gundaker, Grey

    2007-01-01

    Background/Context: Historical studies examine aspects of African American education in and out of school in detail (Woodson 1915, 1933, Bullock 1970, Anderson 1988, Morris 1982, Rachal 1986, Rose 1964, Webber 1978, Williams 2005). Scholars of African American literacy have noted ways that education intersects other arenas such as religion and…

  19. British African Caribbean Women and Depression

    ERIC Educational Resources Information Center

    Adkison-Bradley, Carla; Maynard, Donna; Johnson, Phillip; Carter, Stephaney

    2009-01-01

    Depression is a common condition among women in the United Kingdom. However, little is known about the context of depression among British African Caribbean women. This article offers a preliminary discussion regarding issues and information pertaining to depression among British African Caribbean women. Characteristics and symptoms of depression…

  20. Depression, Sociocultural Factors, and African American Women

    ERIC Educational Resources Information Center

    Hunn, Vanessa Lynn; Craig, Carlton David

    2009-01-01

    The authors discuss depression in African American women from a sociocultural perspective, including aspects of oppression and racism that affect symptom manifestation. The authors highlight John Henryism as a coping mechanism, the history and continuing role of the African American church as a safe haven, and strategies for culturally competent…

  1. Basement control in the development of the early cretaceous West and Central African rift system

    NASA Astrophysics Data System (ADS)

    Maurin, Jean-Christophe; Guiraud, René

    1993-12-01

    The structural framework of the Precambrian basement of the West and Central African Rift System (WCARS) is described in order to examine the role of ancient structures in the development of this Early Cretaceous rift system. Basement structures are represented in the region by large Pan-African mobile belts (built at ca. 600 Ma) surrounding the > 2 Ga West African, Congo and Sao Francisco cratons. Except for the small Gao trough (eastern Mali) located near the contact nappe of the Pan-African Iforas suture zone along the edge of the West African craton, the entire WCARS is located within the internal domains of the Pan-African mobile belts. Within these domains, two main structural features occur as the main basement control of the WCARS: (1) an extensive network of near vertical shear zones which trend north-south through the Congo, Brazil, Nigeria, Niger and Algeria, and roughly east-west through northeastern Brazil and Central Africa. The shear zones correspond to intra-continental strike-slip faults which accompanied the oblique collision between the West African, Congo, and Sao Francisco cratons during the Late Proterozoic; (2) a steep metamorphic NW-SE-trending belt which corresponds to a pre-Pan-African (ca. 730 Ma) ophiolitic suture zone along the eastern edge of the Trans-Saharian mobile belt. The post-Pan-African magmatic and tectonic evolution of the basement is also described in order to examine the state of the lithosphere prior to the break-up which occurred in the earliest Cretaceous. After the Pan-African thermo-tectonic event, the basement of the WCARS experienced a long period of intra-plate magmatic activity. This widespread magmatism in part relates to the activity of intra-plate hotspots which have controlled relative uplift, subsidence and occasionally block faulting. During the Paleozoic and the early Mesozoic, this tectonic activity was restricted to west of the Hoggar, west of Aïr and northern Cameroon. During the Late Jurassic

  2. Geochemistry of East African Rift basalts: An overview

    NASA Astrophysics Data System (ADS)

    Furman, Tanya

    2007-06-01

    Mafic lavas erupted along the East African Rift System from the Afar triangle in northern Ethiopia to the Rungwe province in southern Tanzania display a wide range of geochemical and isotopic compositions that reflect heterogeneity in both source and process. In areas with the lowest degree of crustal extension (the Western and Southern Kenya Rifts) primitive lavas record the greatest extent of lithospheric melting, manifest in elevated abundances of incompatible elements and highly radiogenic Sr-Nd-Pb isotopic compositions. Where prolonged extension has removed most or all of the mantle lithosphere (the Turkana and Northern Kenya Rifts), a larger role for sub-lithospheric processes is indicated. At intermediate degrees of extension (the Main Ethiopian Rift) both lithospheric and sub-lithospheric contributions are observed, and crustal assimilation occurs in some cases. Despite the wide compositional range of African Rift basalts, a restricted number of source domains contribute to magmatism throughout the area. These individual domains are: (1) the subcontinental mantle lithosphere; (2) a plume source with high-μ Sr-Nd-Pb-He isotopic affinities, present in all areas within and south of the Turkana Depression; and (3) a plume source with isotopic signatures analogous to those observed in some ocean islands, including high 3He/ 4He values, present throughout the Ethiopian Rift and the Afar region. The two plume sources may both be derived from the South African Superplume, which is likely to be a compositionally heterogeneous feature of the lower mantle.

  3. Spatial air pollution modelling for a West-African town.

    PubMed

    Gebreab, Sirak Zenebe; Vienneau, Danielle; Feigenwinter, Christian; Bâ, Hâmpaté; Cissé, Guéladio; Tsai, Ming-Yi

    2015-01-01

    Land use regression (LUR) modelling is a common approach used in European and Northern American epidemiological studies to assess urban and traffic related air pollution exposures. Studies applying LUR in Africa are lacking. A need exists to understand if this approach holds for an African setting, where urban features, pollutant exposures and data availability differ considerably from other continents. We developed a parsimonious regression model based on 48-hour nitrogen dioxide (NO2) concentrations measured at 40 sites in Kaédi, a medium sized West-African town, and variables generated in a geographic information system (GIS). Road variables and settlement land use characteristics were found to be important predictors of 48-hour NO2 concentration in the model. About 68% of concentration variability in the town was explained by the model. The model was internally validated by leave-one-out cross-validation and it was found to perform moderately well. Furthermore, its parameters were robust to sampling variation. We applied the model at 100 m pixels to create a map describing the broad spatial pattern of NO2 across Kaédi. In this research, we demonstrated the potential for LUR as a valid, cost-effective approach for air pollution modelling and mapping in an African town. If the methodology were to be adopted by environmental and public health authorities in these regions, it could provide a quick assessment of the local air pollution burden and potentially support air pollution policies and guidelines. PMID:26618306

  4. Selective breeding: the future of TB management in African buffalo?

    PubMed

    le Roex, N; Berrington, C M; Hoal, E G; van Helden, P D

    2015-09-01

    The high prevalence of bovine tuberculosis (BTB) in African buffalo (Syncerus caffer) in regions of southern African has a negative economic impact on the trade of animals and animal products, represents an ecological threat to biodiversity, and poses a health risk to local communities through the wildlife-cattle-human interface. Test and cull methods may not be logistically feasible in many free-range wildlife systems, and with the presence of co-existing BTB hosts and the limited effectiveness of the BCG vaccine in buffalo, there is a need for alternative methods of BTB management. Selective breeding for increased resistance to BTB in buffalo may be a viable method of BTB management in the future, particularly if genetic information can be incorporated into these schemes. To explore this possibility, we discuss the different strategies that can be employed in selective breeding programmes, and consider the implementation of genetic improvement schemes. We reflect on the suitability of applying this strategy for enhanced BTB resistance in African buffalo, and address the challenges of this approach that must be taken into account. Conclusions and the implications for management are presented. PMID:25985909

  5. Cardiovascular disease, diabetes and established risk factors among populations of sub-Saharan African descent in Europe: a literature review

    PubMed Central

    Agyemang, Charles; Addo, Juliet; Bhopal, Raj; de Graft Aikins, Ama; Stronks, Karien

    2009-01-01

    Background Most European countries are ethnically and culturally diverse. Globally, cardiovascular disease (CVD) is the leading cause of death. The major risk factors for CVD have been well established. This picture holds true for all regions of the world and in different ethnic groups. However, the prevalence of CVD and related risk factors vary among ethnic groups. Methods This article provides a review of current understanding of the epidemiology of vascular disease, principally coronary heart disease (CHD), stroke and related risk factors among populations of Sub-Sahara African descent (henceforth, African descent) in comparison with the European populations in Europe. Results Compared with European populations, populations of African descent have an increased risk of stroke, whereas CHD is less common. They also have higher rates of hypertension and diabetes than European populations. Obesity is highly prevalent, but smoking rate is lower among African descent women. Older people of African descent have more favourable lipid profile and dietary habits than their European counterparts. Alcohol consumption is less common among populations of African descent. The rate of physical activity differs between European countries. Dutch African-Suriname men and women are less physically active than the White-Dutch whereas British African women are more physically active than women in the general population. Literature on psychosocial stress shows inconsistent results. Conclusion Hypertension and diabetes are highly prevalent among African populations, which may explain their high rate of stroke in Europe. The relatively low rate of CHD may be explained by the low rates of other risk factors including a more favourable lipid profile and the low prevalence of smoking. The risk factors are changing, and on the whole, getting worse especially among African women. Cohort studies and clinical trials are therefore needed among these groups to determine the relative

  6. Intimate partner violence in African American women.

    PubMed

    Campbell, Doris Williams; Sharps, Phyllis W; Gary, Faye A; Campbell, Jacquelyn C; Lopez, Loretta M

    2002-01-01

    Violence against African American women, specifically intimate partner abuse, has a significant impact on their health and well being. Intimate partner femicide and near fatal intimate partner femicide are the major causes of premature death and disabling injuries for African American women. Yet, despite this, there is a paucity of research and interventions specific and culturally relevant for these women. This article focuses on issues relevant to intimate partner violence and abuse against African American women by examining existing empirical studies of prevalence and health outcomes of intimate partner violence against women in general, plus what limited research there is about African American women, specifically. It includes a discussion of specific recommendations for research, practice, education, and policy to reduce and prevent intimate partner violence against African American women. PMID:12044219

  7. Suicidal behavior in black South Africans.

    PubMed

    Schlebusch, Lourens; Vawda, Naseema B M; Bosch, Brenda A

    2003-01-01

    In the past suicidal behavior among Black South Africans has been largely underresearched. Earlier studies among the other main ethnic groups in the country showed suicidal behavior in those groups to be a serious problem. This article briefly reviews some of the more recent research on suicidal behavior in Black South Africans. The results indicate an apparent increase in suicidal behavior in this group. Several explanations are offered for the change in suicidal behavior in the reported clinical populations. This includes past difficulties for all South Africans to access health care facilities in the Apartheid (legal racial separation) era, and present difficulties of post-Apartheid transformation the South African society is undergoing, as the people struggle to come to terms with the deleterious effects of the former South African racial policies, related socio-cultural, socio-economic, and other pressures. PMID:12809149

  8. African electricity infrastructure, interconnections and exchanges

    SciTech Connect

    Hammons, T.J.; Taher, F.; Gulstone, A.B.; Blyden, B.K.; Johnston, R.; Isekemanga, E.; Paluku, K.; Calitz, A.C.; Simanga, N.N.

    1997-01-01

    A 1996 IEEE PES Summer Meeting panel session focused on African Electricity Infrastructure, Interconnections, and Electricity Exchanges. The session was sponsored by the PES Energy Development and Power Generation Committee and organized/moderated by T.J. Hammons, chair of the International Practices Subcommittee. Panelists discussed energy resources, feasibility studies to interconnect power systems, the present state of the electric power sector, future expansion of African power systems, interconnections and power exchanges, and the impact of the private sector on electricity supply. The presentations were as follows: Prospects of the Evolution of a Unified Interconnection Power System in Africa, Fouad Taher; The World Bank`s Involvement with African Electricity Infrastructure, Alfred Gulstone; Towards the implementation of an Integrated African Grid, Bai K. Blyden, Raymond Johnston; Grand Inga Interconnection Projects, Elese Isekemanga, K. Paluku; The Innovative Southern African Kilowatt Hour, Andries C. Calitz; Report on Burundi, Rwanda, and Zaire, Ngove-Ngulu Simanga.

  9. Drivers of Recent Trends in African Landscape Fires

    NASA Astrophysics Data System (ADS)

    Andela, N.; van der Werf, G.

    2014-12-01

    Landscape fires play an important role in savannah ecosystem dynamics and are an important source of emissions of (greenhouse) gases and aerosols. Within the Monitoring Atmospheric Composition and Climate (MACC) project these fires are monitored using MODIS satellite data which now provides more than a decade of continuous observations. Africa is nowadays responsible for about 70% of global burned area and about 50% of fire carbon emissions, affecting regional air quality and global atmospheric composition. Although it has been reported that fire activity varies according to climatic and anthropogenic influences, much remains unclear about the drivers of the spatial distribution of fire activity over the African continent and its temporal dynamics. Resolving the drivers of this spatiotemporal variability is crucial to understand the future role of fire on the African continent. We developed a model to account for variations in fire activity due to climate, and investigated the role of sea surface temperatures on rainfall patterns and thus fire dynamics. Spatial variation and trends in cropland extent were used to improve understanding of underlying trends caused by socio-economic changes. Over 2001-2012, satellite observations indicate strong but opposing trends in the African hemispheres. Changes in precipitation, driven by the El Niño/Southern Oscillation (ENSO), which changed from El Niño to la Niña dominance over the study period, contributed substantially to the upward trend over southern Africa. This shift also contributed to the downward trend in northern Africa, but here rapid demographic and socio-economic developments contributed equally. Given the economic perspective of Africa and the oscillative nature of ENSO, future African savannah burned area will likely decline. Using MACC and GFED emissions estimates we expect that in the long term this decrease may be so substantial that forests may take over savannas as the main source of global fire

  10. Genetic risk variants in African Americans with multiple sclerosis

    PubMed Central

    Isobe, Noriko; Gourraud, Pierre-Antoine; Harbo, Hanne F.; Caillier, Stacy J.; Santaniello, Adam; Khankhanian, Pouya; Maiers, Martin; Spellman, Stephen; Cereb, Nezih; Yang, SooYoung; Pando, Marcelo J.; Piccio, Laura; Cross, Anne H.; De Jager, Philip L.; Cree, Bruce A.C.; Hauser, Stephen L.

    2013-01-01

    Objectives: To assess the association of established multiple sclerosis (MS) risk variants in 3,254 African Americans (1,162 cases and 2,092 controls). Methods: Human leukocyte antigen (HLA)-DRB1, HLA-DQB1, and HLA-A alleles were typed by molecular techniques. Single nucleotide polymorphism (SNP) genotyping was conducted for 76 MS-associated SNPs and 52 ancestry informative marker SNPs selected throughout the genome. Self-declared ancestry was refined by principal component analysis of the ancestry informative marker SNPs. An ancestry-adjusted multivariate model was applied to assess genetic associations. Results: The following major histocompatibility complex risk alleles were replicated: HLA-DRB1*15:01 (odds ratio [OR] = 2.02 [95% confidence interval: 1.54–2.63], p = 2.50e-07), HLA-DRB1*03:01 (OR = 1.58 [1.29–1.94], p = 1.11e-05), as well as HLA-DRB1*04:05 (OR = 2.35 [1.26–4.37], p = 0.007) and the African-specific risk allele of HLA-DRB1*15:03 (OR = 1.26 [1.05–1.51], p = 0.012). The protective association of HLA-A*02:01 was confirmed (OR = 0.72 [0.55–0.93], p = 0.013). None of the HLA-DQB1 alleles were associated with MS. Using a significance threshold of p < 0.01, outside the major histocompatibility complex region, 8 MS SNPs were also found to be associated with MS in African Americans. Conclusion: MS genetic risk in African Americans only partially overlaps with that of Europeans and could explain the difference of MS prevalence between populations. PMID:23771490

  11. South African AIDS plan criticised.

    PubMed

    Sidley, P

    1998-10-17

    In a television broadcast, Deputy President Mbeki of South Africa announced a campaign against HIV/AIDS that would involve coordination between various government departments and nongovernmental organizations. Mbeki, who is associated with Virodene (a drug treatment for AIDS that is considered a scam), replaced President Mandela at the last minute in the broadcast. Two days after the broadcast, the government refused to support treatment of pregnant women infected with HIV with zidovudine to prevent transmission of the virus to the baby. The treatment is considered cost-effective by AIDS workers and public health officials. According to Mark Heywood of the AIDS law project at Witwatersrand University, 16% of pregnant women attending antenatal clinics were HIV-positive in 1997; this means that about 3 million South Africans (8% of the population) were living with HIV. Heywood said that the government believes there are 1500 new cases daily. By the end of 1998, 3.5 million South Africans will be living with HIV. Although the government is asking other sectors to join in the campaign, what the government is doing is unclear. Mother-to-child transmission of HIV is second only to transmission of the virus through heterosexual sex in South Africa. PMID:9841037

  12. Personal, Professional, and Sociocultural Experiences of African American Female School Leaders

    ERIC Educational Resources Information Center

    Robinson, Armentress D.

    2014-01-01

    The purpose of this phenomenological study was to explore and gain an in-depth understanding of the personal, professional, and sociocultural experiences of ten African American female school leaders serving as assistant principals, principals, and central office administrators in four suburban school districts in the southeast region of the…

  13. Current Trends, Challenges and Prospects of Student Mobility in the African Higher Education Landscape

    ERIC Educational Resources Information Center

    Woldegiorgis, Emnet Tadesse; Doevenspeck, Martin

    2015-01-01

    Since the 1990s, the development in the international dimension of higher education including student/scholar mobility, regional and international research networks and initiatives have brought new opportunities for African higher education to be incorporated in the global knowledge production and circulation processes. One of the instruments of…

  14. African Geography for Schools: A Handbook for Teachers. A Unesco Source Book.

    ERIC Educational Resources Information Center

    Brouillette, B., Ed.; And Others

    This book is the first in a series of UNESCO guide books for teaching geography on a continental scale, dealing with either land masses or vast regional groups which have common characteristics. Written by African geographers, it is intended for primary and secondary school teachers, teacher-training institutions in Africa, and also for geography…

  15. 21st Century African Philosophy of Adult and Human Resource Education in Southern Africa

    ERIC Educational Resources Information Center

    Mutamba, Charlene

    2012-01-01

    This paper will attempt to define a philosophy of adult education for the purpose of workforce development in Southern Africa. The different influences such as Ubuntu and communalism, indigenous education, diversity western philosophy, globalization and technology are explored in the context of the Southern African region.

  16. Data Networks and Sustainability Education in African Universities: A Case Study for Sub-Saharan Africa

    ERIC Educational Resources Information Center

    Bothun, Gregory D.

    2016-01-01

    Purpose: The purpose of this paper is to provide a case study report of the development of data networks and initial connectivity in the Sub-Saharan African (SSA) region and how that development evolved into the formation of research and education (R&E) networks that enable new collaborations and curriculum potential.…

  17. Brains and brain components in African and European honey bees (Hymenoptera: Apidae) - a volumetric comparison

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to determine if the volume of major regions of the brain and the capacity for associative learning differed between European (AHB) and African honey bees (AHB). Associative learning was measured in 14-day old workers and foragers using proboscis extension response to odor-suga...

  18. African American Student Athletes' Perceptions of Career Transition in Sport: A Qualitative and Visual Elicitation

    ERIC Educational Resources Information Center

    Harrison, C. Keith; Lawrence, Suzanne Malia

    2003-01-01

    This study focuses on 26 African American athletes and explores their perceptions of athletic career transition. Participants consisted of student athletes from a United States National Collegiate Athletic Association (NCAA) Division IIA institution in the Southeastern region. Participants completed the Life After Sports Scale (LASS), a 58-item…

  19. The Nurturant Fathering Scale: A Confirmatory Factor Analysis with an African American Sample of College Students

    ERIC Educational Resources Information Center

    Doyle, Otima; Pecukonis, Edward; Harrington, Donna

    2011-01-01

    Objective: The objective of this study was to test the factor structure of the "Nurturant Fathering Scale" (NFS) among an African American sample in the mid-Atlantic region that have neither Caribbean heritage nor immigration experiences but who do have diverse family structures (N = 212). Method: A confirmatory factor analysis (CFA) was conducted…

  20. Resource geopolitics: US dependence on South African chromium

    SciTech Connect

    Butts, K.H.

    1985-01-01

    The growth of technology, especially military technology, has heightened demand for certain critical mineral resources. Strategically important to the industrialized nations, these resources are increasingly available only through overseas trade. The concentration of many of these resources in politically unstable areas of the world has rendered the industrialized nations vulnerable to supply dislocation. Nowhere is this more evident than in the dependence of the United States (US) upon African minerals. This study examines these dependencies, especially with respect to South Africa's chromium and ferrochromium, in order to address the geopolitically important variables concerning resource access and the determination of US policy toward the mineral-rich region of Southern Africa.

  1. Genome Size Variations in Diploid African Coffea Species

    PubMed Central

    NOIROT, M.; PONCET, V.; BARRE, P.; HAMON, P.; HAMON, S.; DE KOCHKO, A.

    2003-01-01

    Flow cytometry was conducted to evaluate genome size diversity among African diploid species of the Coffea genus. The study included 15 species and six new taxa from Congolese and Cameroonian forest regions which have yet to be botanically characterized. Between‐population differences were also recorded in some cases. These evaluations using an internal standard were highly correlated with previous results obtained with an external standard, but differences of up to 18 % existed for some species, involving stoichiometric errors. Consequently, genome size variation between species and within species are discussed as true genome size differences or stoichiometric errors. Environmental and phenotypic correlations with genome size are also discussed. PMID:14573524

  2. Fatigue Severity among African Americans: Gender and Age Interactions.

    ERIC Educational Resources Information Center

    Song, Sharon; Jason, Leonard A.; Taylor, Renee R.; Torres-Harding, Susan R.; Helgerson, Jena; Witter, Elizabeth

    2002-01-01

    Investigated the relationship between fatigue, age, and gender among African Americans, Caucasians, and Latinos. Survey results found significant age and gender interactions among African Americans and Caucasians. African American women and older African American men had the highest fatigue rates. There was no significant difference in levels of…

  3. The Notion of Ubuntu and Communalism in African Educational Discourse

    ERIC Educational Resources Information Center

    Venter, Elza

    2004-01-01

    The notion of "ubuntu" and "communalism" is of great importance in an African educational discourse, as well as in African Philosophy of Education and in African philosophical discourse. "Ubuntu" is a philosophy that promotes the common good of society and includes humanness as an essential element of human growth. In African culture the community…

  4. The African-American History of Martha's Vineyard.

    ERIC Educational Resources Information Center

    Weintraub, Elaine

    1993-01-01

    Reports on research into African American history and experiences in Martha's Vineyard (Massachusetts). Examines primary sources and oral traditions of African American cultural and social history from 1703 to the present. Discusses African American sailors, race relations, and contributions by African American individuals to the community. (CFR)

  5. Educational Adaptation and Pan-Africanism: Trends in Africa.

    ERIC Educational Resources Information Center

    Marah, John Karefah

    1987-01-01

    European colonialists believed that Africans should be educated in African traditional values, and that Africans should be made into dedicated workers, not holders of power. The African nationalists of the 1960s, in contrast, rejected most of the arduous aspects of European education as instruments of domination, and lay the foundation for the…

  6. The Call for an African University: A Critical Reflection

    ERIC Educational Resources Information Center

    van Wyk, Berte; Higgs, Philip

    2007-01-01

    In this paper, we draw on philosophy (particularly African philosophy) to analyse the call for an African university. The call for an African university may be viewed as a call that insists that all critical and transformative educators in Africa embrace an indigenous African worldview and root their nation's educational paradigms in an indigenous…

  7. A comprehensive examination of breast cancer risk loci in African American women.

    PubMed

    Feng, Ye; Stram, Daniel O; Rhie, Suhn Kyong; Millikan, Robert C; Ambrosone, Christine B; John, Esther M; Bernstein, Leslie; Zheng, Wei; Olshan, Andrew F; Hu, Jennifer J; Ziegler, Regina G; Nyante, Sarah; Bandera, Elisa V; Ingles, Sue A; Press, Michael F; Deming, Sandra L; Rodriguez-Gil, Jorge L; Palmer, Julie R; Olopade, Olufunmilayo I; Huo, Dezheng; Adebamowo, Clement A; Ogundiran, Temidayo; Chen, Gary K; Stram, Alex; Park, Karen; Rand, Kristin A; Chanock, Stephen J; Le Marchand, Loic; Kolonel, Laurence N; Conti, David V; Easton, Douglas; Henderson, Brian E; Haiman, Christopher A

    2014-10-15

    Genome-wide association studies have identified 73 breast cancer risk variants mainly in European populations. Given considerable differences in linkage disequilibrium structure between populations of European and African ancestry, the known risk variants may not be informative for risk in African ancestry populations. In a previous fine-mapping investigation of 19 breast cancer loci, we were able to identify SNPs in four regions that better captured risk associations in African American women. In this study of breast cancer in African American women (3016 cases, 2745 controls), we tested an additional 54 novel breast cancer risk variants. Thirty-eight variants (70%) were found to have an association with breast cancer in the same direction as previously reported, with eight (15%) replicating at P < 0.05. Through fine-mapping, in three regions (1q32, 3p24, 10q25), we identified variants that better captured associations with overall breast cancer or estrogen receptor positive disease. We also observed suggestive associations with variants (at P < 5 × 10(-6)) in three separate regions (6q25, 14q13, 22q12) that may represent novel risk variants. Directional consistency of association observed for ∼65-70% of currently known genetic variants for breast cancer in women of African ancestry implies a shared functional common variant at most loci. To validate and enhance the spectrum of alleles that define associations at the known breast cancer risk loci, as well as genome-wide, will require even larger collaborative efforts in women of African ancestry. PMID:24852375

  8. The influence of hybridization between African and European honeybees, Apis mellifera, on asymmetries in wing size and shape.

    PubMed

    Schneider, S S; Leamy, L J; Lewis, L A; DeGrandi-Hoffman, G

    2003-10-01

    We examined the possible role of hybridization in the invasion process of the African honeybee by testing two hypotheses regarding fluctuating asymmetry (FA), a measure of developmental stability, in wing characteristics: (1) FA should be higher in hybrid versus parental genotypes of African and European races; (2) FA should be lower in African bees compared to hybrid and European workers. Parental and reciprocal hybrid worker genotypes were cross fostered in common-hive rearing environments. We did not find greater FA for wing size and shape in the hybrids compared to both parental types. However, we did find significantly lower FA of shape in the African workers compared to the European and hybrid workers, suggesting that European bees and their hybrids may have compromised fitness relative to African bees. We also found that the two hybrid genotypes significantly differed in overall wing size and shape. If these differences affect wing aerodynamics, then the paternity of hybrids may influence worker performance and could potentially contribute to the loss of European matrilines. Hybridization had few consistent effects on directional asymmetry for wing size and shape. Genotypic factors played a far greater role in determining the effect of hybridization on wing morphology than did differences in rearing environment. Thus, African bees may have lower FA for wing shape (and by inference greater developmental stability) relative to European and hybrid workers, which may contribute to the ability of African bees to displace European honeybee races in invaded regions. PMID:14628923

  9. Pre-colonial Ethnic Institutions and Contemporary African Development*

    PubMed Central

    Michalopoulos, Stelios; Papaioannou, Elias

    2013-01-01

    We investigate the role of deeply-rooted pre-colonial ethnic institutions in shaping comparative regional development within African countries. We combine information on the spatial distribution of ethnicities before colonization with regional variation in contemporary economic performance, as proxied by satellite images of light density at night. We document a strong association between pre-colonial ethnic political centralization and regional development. This pattern is not driven by differences in local geographic features or by other observable ethnic-specific cultural and economic variables. The strong positive association between pre-colonial political complexity and contemporary development obtains also within pairs of adjacent ethnic homelands with different legacies of pre-colonial political institutions. PMID:25089052

  10. Seroprevalence of African Swine Fever in Senegal, 2006

    PubMed Central

    Seck, Ismaila; Grosbois, Vladimir; Jori, Ferran; Blanco, Esther; Vial, Laurence; Akakpo, Ayayi J.; Bada-Alhambedji, Rianatou; Kone, Philippe; Roger, Francois L.

    2011-01-01

    In Senegal, during 2002–2007, 11 outbreaks of African swine fever (ASF) were reported to the World Organisation for Animal Health. Despite this, little was known of the epidemiology of ASF in the country. To determine the prevalence of ASF in Senegal in 2006, we tested serum specimens collected from a sample of pigs in the 3 main pig-farming regions for antibodies to ASF virus using an ELISA. Of 747 serum samples examined, 126 were positive for ASF, suggesting a prevalence of 16.9%. The estimated prevalences within each of the regions (Fatick, Kolda, and Ziguinchor) were 13.3%, 7.8%, and 22.1%, respectively, with statistical evidence to suggest that the prevalence in Ziguinchor was higher than in Fatick or Kolda. This regional difference is considered in relation to different farming systems and illegal trade with neighboring countries where the infection is endemic. PMID:21192854

  11. Comparison of different evaporation estimates over the African continent

    NASA Astrophysics Data System (ADS)

    Trambauer, P.; Dutra, E.; Maskey, S.; Werner, M.; Pappenberger, F.; van Beek, L. P. H.; Uhlenbrook, S.

    2014-01-01

    Evaporation is a key process in the water cycle with implications ranging, inter alia, from water management to weather forecast and climate change assessments. The estimation of continental evaporation fluxes is complex and typically relies on continental-scale hydrological models or land-surface models. However, it appears that most global or continental-scale hydrological models underestimate evaporative fluxes in some regions of Africa, and as a result overestimate stream flow. Other studies suggest that land-surface models may overestimate evaporative fluxes. In this study, we computed actual evaporation for the African continent using a continental version of the global hydrological model PCR-GLOBWB, which is based on a water balance approach. Results are compared with other independently computed evaporation products: the evaporation results from the ECMWF reanalysis ERA-Interim and ERA-Land (both based on the energy balance approach), the MOD16 evaporation product, and the GLEAM product. Three other alternative versions of the PCR-GLOBWB hydrological model were also considered. This resulted in eight products of actual evaporation, which were compared in distinct regions of the African continent spanning different climatic regimes. Annual totals, spatial patterns and seasonality were studied and compared through visual inspection and statistical methods. The comparison shows that the representation of irrigation areas has an insignificant contribution to the actual evaporation at a continental scale with a 0.5° spatial resolution when averaged over the defined regions. The choice of meteorological forcing data has a larger effect on the evaporation results, especially in the case of the precipitation input as different precipitation input resulted in significantly different evaporation in some of the studied regions. ERA-Interim evaporation is generally the highest of the selected products followed by ERA-Land evaporation. In some regions, the satellite

  12. Unequal contribution of native South African phylogeographic lineages to the invasion of the African clawed frog, Xenopus laevis, in Europe

    PubMed Central

    Courant, Julien; Herrel, Anthony; Rebelo, Rui; Rödder, Dennis; Measey, G. John; Backeljau, Thierry

    2016-01-01

    Due to both deliberate and accidental introductions, invasive African Clawed Frog (Xenopus laevis) populations have become established worldwide. In this study, we investigate the geographic origins of invasive X. laevis populations in France and Portugal using the phylogeographic structure of X. laevis in its native South African range. In total, 80 individuals from the whole area known to be invaded in France and Portugal were analysed for two mitochondrial and three nuclear genes, allowing a comparison with 185 specimens from the native range. Our results show that native phylogeographic lineages have contributed differently to invasive European X. laevis populations. In Portugal, genetic and historical data suggest a single colonization event involving a small number of individuals from the south-western Cape region in South Africa. In contrast, French invasive X. laevis encompass two distinct native phylogeographic lineages, i.e., one from the south-western Cape region and one from the northern regions of South Africa. The French X. laevis population is the first example of a X. laevis invasion involving multiple lineages. Moreover, the lack of population structure based on nuclear DNA suggests a potential role for admixture within the invasive French population. PMID:26855879

  13. Unequal contribution of native South African phylogeographic lineages to the invasion of the African clawed frog, Xenopus laevis, in Europe.

    PubMed

    De Busschere, Charlotte; Courant, Julien; Herrel, Anthony; Rebelo, Rui; Rödder, Dennis; Measey, G John; Backeljau, Thierry

    2016-01-01

    Due to both deliberate and accidental introductions, invasive African Clawed Frog (Xenopus laevis) populations have become established worldwide. In this study, we investigate the geographic origins of invasive X. laevis populations in France and Portugal using the phylogeographic structure of X. laevis in its native South African range. In total, 80 individuals from the whole area known to be invaded in France and Portugal were analysed for two mitochondrial and three nuclear genes, allowing a comparison with 185 specimens from the native range. Our results show that native phylogeographic lineages have contributed differently to invasive European X. laevis populations. In Portugal, genetic and historical data suggest a single colonization event involving a small number of individuals from the south-western Cape region in South Africa. In contrast, French invasive X. laevis encompass two distinct native phylogeographic lineages, i.e., one from the south-western Cape region and one from the northern regions of South Africa. The French X. laevis population is the first example of a X. laevis invasion involving multiple lineages. Moreover, the lack of population structure based on nuclear DNA suggests a potential role for admixture within the invasive French population. PMID:26855879

  14. Out of Africa: The first introduced African geophilomorph centipede record from a European greenhouse (Chilopoda: Geophilidae).

    PubMed

    Dányi, László; Tuf, Ivan Hadrián

    2016-01-01

    In Europe, 184 species of Geophilomorpha are recognised (Bonato & Minelli 2014) of which eight are evaluated as alien to the region (Stoev et al. 2010, Decker et al. 2014). Four of these have been reported from greenhouses exclusively: Mecistocephalus guildingii Newport, 1843, Mecistocephalus maxillaris (Gervais, 1837), Tygarrup javanicus Attems, 1929 and Pectiniunguis pauperatus Silvestri, 1907. In this paper, we report another species, Polygonarea silvicola Lawrence, 1955, which is the first Geophilomorpha species of unambiguous African origin in Europe. Description of the specimen found in Olomouc (Czech Republic) is provided. Co-occurrence of another African species, the lithobiomorph Lamyctes africanus (Porath, 1871) (also new for Czech Republic) is also reported here. PMID:27395899

  15. Seventy years of the East African Medical Journal towards safe motherhood.

    PubMed

    Ojwang, S B

    1993-06-01

    Obstetrical and gynaecological articles related to safe motherhood published in the East African Medical Journal between 1924 and 1989 were reviewed. A total of 133 topics were published. Out of these, 84 (63.2%) were obstetrical and 49 (36.8%) gynaecological. Out of the obstetrical topics, 66 were pregnancy related, 12 were public health and the rest medical topics. A rapid increase in the number of the relevant topics is seen especially after 1970. This is probably due to the increase in the number of of obstetricians training locally in the African region and the international nature of the Journal during the last two decades. PMID:8261963

  16. Will Elephants Soon Disappear from West African Savannahs?

    PubMed Central

    Bouché, Philippe; Douglas-Hamilton, Iain; Wittemyer, George; Nianogo, Aimé J.; Doucet, Jean-Louis; Lejeune, Philippe; Vermeulen, Cédric

    2011-01-01

    Precipitous declines in Africa's native fauna and flora are recognized, but few comprehensive records of these changes have been compiled. Here, we present population trends for African elephants in the 6,213,000 km2 Sudano-Sahelian range of West and Central Africa assessed through the analysis of aerial and ground surveys conducted over the past 4 decades. These surveys are focused on the best protected areas in the region, and therefore represent the best case scenario for the northern savanna elephants. A minimum of 7,745 elephants currently inhabit the entire region, representing a minimum decline of 50% from estimates four decades ago for these protected areas. Most of the historic range is now devoid of elephants and, therefore, was not surveyed. Of the 23 surveyed elephant populations, half are estimated to number less than 200 individuals. Historically, most populations numbering less than 200 individuals in the region were extirpated within a few decades. Declines differed by region, with Central African populations experiencing much higher declines (−76%) than those in West Africa (−33%). As a result, elephants in West Africa now account for 86% of the total surveyed. Range wide, two refuge zones retain elephants, one in West and the other in Central Africa. These zones are separated by a large distance (∼900 km) of high density human land use, suggesting connectivity between the regions is permanently cut. Within each zone, however, sporadic contacts between populations remain. Retaining such connectivity should be a high priority for conservation of elephants in this region. Specific corridors designed to reduce the isolation of the surveyed populations are proposed. The strong commitment of governments, effective law enforcement to control the illegal ivory trade and the involvement of local communities and private partners are all critical to securing the future of elephants inhabiting Africa's northern savannas. PMID:21731620

  17. Misconceptions of Depression in African Americans

    PubMed Central

    Sohail, Zohaib; Bailey, Rahn Kennedy; Richie, William D.

    2014-01-01

    Major depression is a very common disabling disorder. Although the relationship between race and depression is complex, depression affects all races, all ethnic and geographic locations as well as all age groups. The prevalence of depression in African Americans is controversial, due to the paucity of research. The deficit in the knowledge and skills in treating depression in African Americans have not been adequately addressed so far. Inadequate and insufficient data on African Americans contributes to the problems of under diagnoses, misdiagnosis, and under treatment of depression. This article will highlight the existing problem of depression in Afro American with a focus on diagnostic and treatment issues. PMID:24999332

  18. Discussing Cancer: Communication with African Americans

    PubMed Central

    Caito, Nikki; Hood, Sula; Thompson, Vetta L. Sanders

    2015-01-01

    Regular screening for colorectal cancer (CRC) facilitates earlier detection, lowers mortality, and may reduce incidence through detection and removal of pre-cancerous polyps. Optimizing health professional delivery of CRC screening information and recommendations can assist in reducing CRC disparity in the African American community. This paper presents qualitative data on African Americans’ attitudes about health professional CRC communications based on the analysis of focus groups (N=79). Using a social-ecological framework, colorectal cancer and professional communication themes are examined to offer four general and nine cancer specific theoretically based and culturally appropriate strategies for improving health professional cancer communication with African Americans. PMID:25050658

  19. Assessing spirituality in mentally ill African Americans.

    PubMed

    Perdue, Bobbie; Johnson, Deanna; Singley, Doretha; Jackson, Cheylon

    2006-01-01

    The case scenario illustrates the advantage of using spirituality as a tool for recovery when working with mentally ill African American clients. Often spiritual and clinical perspectives are seen as contradictory. But for African Americans, these perspectives can be mutually reinforcing. Spirituality can serve as a resource of strength. It can provide emotional consolation, inspiration, guidance, and security. It can foster personal responsibility, identity, respect for ethical codes and community building. Mental Health professionals who use spirituality as a tool for recovery can expect to have better client outcomes when working with African Americans than those who do not. PMID:18402348

  20. Iron mobilization in North African dust.

    SciTech Connect

    Ito, A.; Feng, Y.

    2011-01-01

    Iron is an essential nutrient for phytoplankton. Although iron-containing dust mobilized from arid regions supplies the majority of the iron to the oceans, the key flux in terms of the biogeochemical response to atmospheric deposition is the amount of soluble or bioavailable iron. Atmospheric processing of mineral aerosols by anthropogenic pollutants (e.g. sulfuric acid) may transform insoluble iron into soluble forms. Previous studies have suggested higher iron solubility in smaller particles, as they are subject to more thorough atmospheric processing due to a longer residence time than coarse particles. On the other hand, the specific mineralogy of iron in dust may also influence the particulate iron solubility in size. Compared to mineral dust aerosols, iron from combustion sources could be more soluble, and found more frequently in smaller particles. Internal mixing of alkaline dust with iron-containing minerals could significantly reduce iron dissolution in large dust aerosols due to the buffering effect, which may, in contrast, yield higher solubility in smaller particles externally mixed with alkaline dust (Ito and Feng, 2010). Here, we extend the modeling study of Ito and Feng (2010) to investigate atmospheric processing of mineral aerosols from African dust. In contrast to Asian dust, we used a slower dissolution rate for African dust in the fine mode. We compare simulated fractional iron solubility with observations. The inclusion of alkaline compounds in aqueous chemistry substantially limits the iron dissolution during long-range transport to the Atlantic Ocean: only a small fraction of iron (<0.2%) dissolves from illite in coarsemode dust aerosols with 0.45% soluble iron initially. In contrast, a significant fraction (1-1.5%) dissolves in fine-mode dust aerosols due to the acid mobilization of the iron-containing minerals externally mixed with carbonate minerals. Consequently, the model generally reproduces higher iron solubility in smaller particles

  1. HLA disease association and protection in HIV infection among African Americans and Caucasians.

    PubMed

    Cruse, J M; Brackin, M N; Lewis, R E; Meeks, W; Nolan, R; Brackin, B

    1991-01-01

    In a previous investigation, we demonstrated an increased progression of overt AIDS in the African American population compared to the Caucasian population as reflected by the significantly lower absolute number of CD4+ lymphocytes detected in the African American population in an earlier study. The present study elucidates some of the possible genetic factors which may contribute to disease association or protection against HIV infection. The HLA phenotypes expressed as A, B, C, DR and DQw antigens were revealed by the Amos-modified typing procedure. NIH scoring was utilized to designate positive cells taking up trypan blue. A test of proportion equivalent to the chi 2 approximation was used to compare the disease population (n = 62; 38 African Americans, 24 Caucasians) to race-matched normal heterosexual local controls (323 African Americans, 412 Caucasians). Significant p values were corrected for the number of HLA antigens tested. HLA markers associated with possible protection from infection for African Americans were Cw4 and DRw6, whereas Caucasians expressed none. Disease association markers present in the African American population were A31, B35, Cw6, Cw7, DR5, DR6, DRw11, DRw12, DQw6 and DQw7, whereas in the Caucasian population A28, Aw66, Aw48, Bw65, Bw70, Cw7, DRw10, DRw12, DQw6 and DQw7 were demonstrated. The highest phenotypic frequency for a disease association marker in the study was for HLA-DR5 (62.9%) in the HIV-infected African American population without Kaposi's sarcoma compared to a frequency of 28.9% for the regional control group (p = 0.0012). We conclude that genetic factors do have a role in HIV infection since only 50-60% of those exposed to the AIDS virus will become infected. PMID:1910527

  2. Enhancing the African bioethics initiative

    PubMed Central

    Ogundiran, Temidayo O

    2004-01-01

    Background Medical ethics has existed since the time of Hippocrates. However, formal training in bioethics did not become established until a few decades ago. Bioethics has gained a strong foothold in health sciences in the developed world, especially in Europe and North America. The situation is quite different in many developing countries. In most African countries, bioethics – as established and practiced today in the west- is either non-existent or is rudimentary. Discussion Though bioethics has come of age in the developed and some developing countries, it is still largely "foreign" to most African countries. In some parts of Africa, some bioethics conferences have been held in the past decade to create research ethics awareness and ensure conformity to international guidelines for research with human participants. This idea has arisen in recognition of the genuine need to develop capacity for reviewing the ethics of research in Africa. It is also a condition required by external sponsors of collaborative research in Africa. The awareness and interest that these conferences have aroused need to be further strengthened and extended beyond research ethics to clinical practice. By and large, bioethics education in schools that train doctors and other health care providers is the hook that anchors both research ethics and clinical ethics. Summary This communication reviews the current situation of bioethics in Africa as it applies to research ethics workshops and proposes that in spite of the present efforts to integrate ethics into biomedical research in Africa, much still needs to be done to accomplish this. A more comprehensive approach to bioethics with an all-inclusive benefit is to incorporate formal ethics education into health training institutions in Africa. PMID:15488145

  3. Influence of CYP2C9 Genotype on warfarin dose among African American and European Americans.

    PubMed

    Limdi, Na; Goldstein, Ja; Blaisdell, Ja; Beasley, Tm; Rivers, Ca; Acton, Rt

    2007-05-01

    BACKGROUND: Cytochrome P4502C9 (CYP2C9) plays a vital role in drug metabolism. There has been an increased effort to identify polymorphisms within the gene and determine their clinical consequences. However, most of these efforts have focused on populations of European descent. Herein we report the influence of CYP2C9 genotype on warfarin dose among European American and African American patients. We also identify two new mutations; one in the coding region and one in the non-coding region of the CYP2C9 gene. METHODS: Patients (≥20 years of age) are enrolled after obtaining medical, lifestyle and concomitant medication history. Changes in International Normalized Ratio (INR), warfarin dose, co-medications, diet, physical activity and the occurrence of complications are documented. CYP2C9 genotype was determined using PCR-RFLP and pyrosequencing. Differences in genotype frequencies and HWE assumptions were assessed using χ(2) statistics and exact tests. The genotype dose association was evaluated using multivariable linear regression. RESULTS: This report includes 490 patients (mean age 60.6 ± 15.6, 51.3% men). African American patients comprise 48.9% of the cohort with mean follow-up of 13.5 (±10.6) months. Both the CYP2C9 *2 and *3 allele were more frequent in European Americans (11.24%, 5.1%) compared to African Americans (1.1% and 1.8%). CYP2C9 *5 (0.9%), *6 (0.4%), and *11 (1.1%) variants were only observed in African Americans. The variant genotype is more frequent among European Americans compared to African Americans (29.8% vs. 9.73%, p<0.0001). Warfarin dose was significantly related to CYP2C9 genotype (p<0.0001) both in univariate and multivariate analyses. Multivariable race-specific analyses highlight the contribution of CYP2C9 genotype among European American but not among African American patients. CONCLUSION: The variant CYP2C9 genotype is more frequent among European Americans compared to African Americans. Among African Americans the variant

  4. African Easterly Jet: Barotropic Instability, Waves, and Cyclogenesis

    NASA Technical Reports Server (NTRS)

    Wu, Man-Li C; Reale, Oreste; Schubert, Siegfried D.; Suarez, Max J.; Thorncroft, Chris D.

    2012-01-01

    This study investigates the structure of the African easterly jet, focusing on instability processes on a seasonal and subseasonal scale, with the goal of identifying features that could provide increased predictability of Atlantic tropical cyclogenesis. The Modern-Era Retrospective Analysis for Research and Applications (MERRA) is used as the main investigating tool. MERRA is compared with other reanalyses datasets from major operational centers around the world and was found to describe very effectively the circulation over the African monsoon region. In particular, a comparison with precipitation datasets from the Global Precipitation Climatology Project shows that MERRA realistically reproduces seasonal precipitation over that region. The verification of the generalized Kuo barotropic instability condition computed from seasonal means is found to have the interesting property of defining well the location where observed tropical storms are detected. This property does not appear to be an artifact of MERRA and is present also in the other adopted reanalysis datasets. Therefore, the fact that the areas where the mean flow is unstable seems to provide a more favorable environment for wave intensification, could be another factor to include-in addition to sea surface temperature, vertical shear, precipitation, the role of Saharan air, and others-among large-scale forcings affecting development and tropical cyclone frequency. In addition, two prominent modes of variability are found based on a spectral analysis that uses the Hilbert-Huang transform: a 2.5-6-day mode that corresponds well to the African easterly waves and also a 6-9-day mode that seems to be associated with tropical- extratropical interaction.

  5. The past, present and future of African dust

    NASA Astrophysics Data System (ADS)

    Evan, Amato T.; Flamant, Cyrille; Gaetani, Marco; Guichard, Françoise

    2016-03-01

    African dust emission and transport exhibits variability on diurnal to decadal timescales and is known to influence processes such as Amazon productivity, Atlantic climate modes, regional atmospheric composition and radiative balance and precipitation in the Sahel. To elucidate the role of African dust in the climate system, it is necessary to understand the factors governing its emission and transport. However, African dust is correlated with seemingly disparate atmospheric phenomena, including the El Niño/Southern Oscillation, the North Atlantic Oscillation, the meridional position of the intertropical convergence zone, Sahelian rainfall and surface temperatures over the Sahara Desert, all of which obfuscate the connection between dust and climate. Here we show that the surface wind field responsible for most of the variability in North African dust emission reflects the topography of the Sahara, owing to orographic acceleration of the surface flow. As such, the correlations between dust and various climate phenomena probably arise from the projection of the winds associated with these phenomena onto an orographically controlled pattern of wind variability. A 161-year time series of dust from 1851 to 2011, created by projecting this wind field pattern onto surface winds from a historical reanalysis, suggests that the highest concentrations of dust occurred from the 1910s to the 1940s and the 1970s to the 1980s, and that there have been three periods of persistent anomalously low dust concentrations—in the 1860s, 1950s and 2000s. Projections of the wind pattern onto climate models give a statistically significant downward trend in African dust emission and transport as greenhouse gas concentrations increase over the twenty-first century, potentially associated with a slow-down of the tropical circulation. Such a dust feedback, which is not represented in climate models, may be of benefit to human and ecosystem health in West Africa via improved air quality and

  6. The past, present and future of African dust.

    PubMed

    Evan, Amato T; Flamant, Cyrille; Gaetani, Marco; Guichard, Françoise

    2016-03-24

    African dust emission and transport exhibits variability on diurnal to decadal timescales and is known to influence processes such as Amazon productivity, Atlantic climate modes, regional atmospheric composition and radiative balance and precipitation in the Sahel. To elucidate the role of African dust in the climate system, it is necessary to understand the factors governing its emission and transport. However, African dust is correlated with seemingly disparate atmospheric phenomena, including the El Niño/Southern Oscillation, the North Atlantic Oscillation, the meridional position of the intertropical convergence zone, Sahelian rainfall and surface temperatures over the Sahara Desert, all of which obfuscate the connection between dust and climate. Here we show that the surface wind field responsible for most of the variability in North African dust emission reflects the topography of the Sahara, owing to orographic acceleration of the surface flow. As such, the correlations between dust and various climate phenomena probably arise from the projection of the winds associated with these phenomena onto an orographically controlled pattern of wind variability. A 161-year time series of dust from 1851 to 2011, created by projecting this wind field pattern onto surface winds from a historical reanalysis, suggests that the highest concentrations of dust occurred from the 1910s to the 1940s and the 1970s to the 1980s, and that there have been three periods of persistent anomalously low dust concentrations--in the 1860s, 1950s and 2000s. Projections of the wind pattern onto climate models give a statistically significant downward trend in African dust emission and transport as greenhouse gas concentrations increase over the twenty-first century, potentially associated with a slow-down of the tropical circulation. Such a dust feedback, which is not represented in climate models, may be of benefit to human and ecosystem health in West Africa via improved air quality and

  7. What role does African ancestry play in how hypertensive patients respond to certain antihypertensive drug therapy?

    PubMed

    Seedat, Yackoob K; Brewster, Lizzy M

    2014-02-01

    This article is a summary of the response of the four commonly used antihypertensive agents in African ancestry patients. They are thiazide like diuretics or indapamide, calcium channel blockers (CCB), angiotensin converting enzyme inhibitors (ACEI) or angiotensin receptor blockers, and β-adrenergic blockers (ARB). Response was superior in African ancestry patients on a thiazide like diuretic or indapamide and CCB, while the response to β-adrenergic blockers and ACEI are attenuated. Available data are very limited but self-defined ancestry seems to be the best predictor of individual responses to antihypertensive drugs. Knowledge of the factors like economic and social consideration affect the lower rate of detection, treatment and control of hypertension in the African ancestry population of the USA. For regions in which health care resources are particularly scarce, investment in population-based primary prevention strategies may yield the largest benefit. PMID:24215578

  8. Religious Media Use Among African Americans, Black Caribbeans, and Non-Hispanic Whites

    PubMed Central

    Chatters, Linda M.

    2014-01-01

    The purpose of this study was to examine the correlates of watching religious television programs and listening to religious radio programs. Data are taken from the National Survey of American Life, a nationally representative study of African Americans, Black Caribbeans, and non-Hispanic Whites. Several significant findings were noted. Both African Americans and Black Caribbeans watched religious television programs and listened to religious radio programs significantly more frequently than non-Hispanic whites. These differences in electronic religious media consumption were particularly large, especially listening to religious radio programming. Among African Americans and Black Caribbeans, several significant demographic differences in frequency of consuming religious programming (e.g., age, gender, region, marital status, immigration status) emerged. Lastly, our analysis found that consuming electronic religious programming did not substitute for attending church service but, instead, complemented weekly service attendance. PMID:26045698

  9. Comparison of different evaporation estimates over the African continent

    NASA Astrophysics Data System (ADS)

    Trambauer, P.; Dutra, E.; Maskey, S.; Werner, M.; Pappenberger, F.; van Beek, L. P. H.; Uhlenbrook, S.

    2013-07-01

    Evaporation is a key process in the water cycle, with implications ranging from water management, to weather forecast and climate change assessments. The estimation of continental evaporation fluxes is complex and typically relies on continental-scale hydrological or land-surface models. However, it appears that most global or continental-scale hydrological models underestimate evaporative fluxes in some regions of Africa, and as a result overestimate stream flow. Other studies suggest that land-surface models may overestimate evaporative fluxes. In this study, we computed actual evaporation for the African continent using a continental version of the global hydrological model PCR-GLOBWB, which is based on a water balance approach. Results are compared with other independently computed evaporation products: the evaporation results from the ECMWF reanalysis ERA-Interim and ERA-Land (both based on the energy balance approach), the MOD16 evaporation product, and the GLEAM product. Three other alternative versions of the PCR-GLOBWB hydrological model were also considered. This resulted in eight products of actual evaporation, which were compared in distinct regions of the African continent spanning different climatic regimes. Annual totals, spatial patterns and seasonality were studied and compared through visual inspection and statistical methods. The comparison shows that the representation of irrigation areas has an insignificant contribution to the actual evaporation at a continental scale with a 0.5° spatial resolution. The choice of meteorological forcing data has a larger effect on the evaporation results, especially in the case of the precipitation input as different precipitation input resulted in significantly different evaporation in some of the studied regions. ERA-Interim evaporation is generally the highest of the selected products followed by ERA-Land evaporation. The satellite based products (GLEAM and MOD16) do not show regular behaviour when compared

  10. Comprehensive Analysis of Pan-African Mitochondrial DNA Variation Provides New Insights into Continental Variation and Demography.

    PubMed

    Cerezo, María; Gusmão, Leonor; Černý, Viktor; Uddin, Nabeel; Syndercombe-Court, Denise; Gómez-Carballa, Alberto; Göbel, Tanja; Schneider, Peter M; Salas, Antonio

    2016-03-20

    Africa is the cradle of all human beings, and although it has been the focus of a number of genetic studies, there are many questions that remain unresolved. We have performed one of the largest and most comprehensive meta-analyses of mitochondrial DNA (mtDNA) lineages carried out in the African continent to date. We generated high-throughput mtDNA single nucleotide polymorphism (SNP) data (230 SNPs) from 2024 Africans, where more than 500 of them were additionally genotyped for the control region. These data were analyzed together with over 12,700 control region profiles collected from the literature, representing more than 300 population samples from Africa. Insights into the African homeland of humans are discussed. Phylogeographic patterns for the African continent are shown at a high phylogeographic resolution as well as at the population and regional levels. The deepest branch of the mtDNA tree, haplogroup L0, shows the highest sub-haplogroup diversity in Southeast and East Africa, suggesting this region as the homeland for modern humans. Several demographic estimates point to the coast as a facilitator of human migration in Africa, but the data indicate complex patterns, perhaps mirroring the effect of recent continental-scaled demographic events in re-shaping African mtDNA variability. PMID:27020033

  11. Cardiac assessment of African hedgehogs (Atelerix albiventris).

    PubMed

    Black, Peter A; Marshall, Cecilia; Seyfried, Alice W; Bartin, Anne M

    2011-03-01

    Cardiomyopathy is a common finding in captive African hedgehogs (Atelerix albiventris) at postmortem exam. To date, treatment attempts have been mostly empirical and unrewarding. The objective of this study was to determine reference cardiac values for captive African hedgehogs based on echocardiogram, electrocardiogram (ECG), and radiographs. Adult African hedgehogs with no clinical signs of cardiac disease (n = 13) were selected. Each animal was anesthetized with isoflurane via facemask and an echocardiogram, ECG, and radiographs were performed. Standard measurements were taken and the descriptive statistics performed. Values were comparable to limited data available in other hedgehog species and other similar-sized exotic species. Two animals were removed from consideration of reference values due to valvular defects that were considered significant. These data are the first establishing cardiac parameters in normal African hedgehogs using radiographic cardiac measurement, echocardiogram, and ECG. Evaluating animals with possible cardiomyopathy may allow for earlier diagnosis and more successful treatment. PMID:22946370

  12. Secretarial Improvement Program for African Office Employees

    ERIC Educational Resources Information Center

    Kurtz, Margaret A.

    1970-01-01

    For the past two years, Colby Junior College, in New London, New Hampshire, in cooperation with Operation Crossroads Africa of New York City, has successfully operated an eight-week secretarial improvement course for African office employees. (Author)

  13. [African research in odontostomatology and international cooperation].

    PubMed

    Berard, A; Page, T; Brouste, Ph; Ndobo-Epoy, Ph

    2004-09-01

    In this study, the authors measure the efficacy of the African odonto-stomatologic research in the International Assocation for Dental Research (I.A.D.R.) and value the impact of the international cooperation upon that research. This evaluation is realized from the number of publications presented by the African countries at the congressess of I.A.D.R. The obtained results show: 1. The African odonto-stomatologic is the less successful in the world and produced, in 1997, 0.4% of the studies published on the world, 2. Some of the African countries are able to produce scientific results of International valour (South Africa, Egypt and Nigeria in a less degree). Generally, these countries work jointly with anglo-saxon universities. 3. During these last two years, Cameroon obtained very encouraging results thanks to his collaboration with the University of Bordeaux 2 (France), represented by the regretted Professeur Ph. NDOBO-EPOY. PMID:15900824

  14. Mellonee Burnim on African American Music.

    ERIC Educational Resources Information Center

    Campbell, Patricia Shehan

    1995-01-01

    Describes the role and influence of Mellonee Burnim on U.S. music education. Discusses the origins and impact of African American gospel music. Includes a list of selected resources and two lesson plans featuring gospel music. (CFR)

  15. African-Americans and Heart Disease, Stroke

    MedlinePlus

    ... more about African-Americans and stroke at our Power To End Stroke website This content was last reviewed July 2015. ... Attack • Heart Failure (HF) • Heart Valve Problems and Disease • High Blood ...

  16. Health Conditions Common in African American Women

    MedlinePlus

    ... health. Return to top Health conditions common in African-American women Asthma Breast cancer Cancer Cervical cancer Diabetes Glaucoma and cataracts Heart disease High blood pressure High cholesterol HIV/AIDS Infant death Kidney disease Lupus Mental health ...

  17. African Americans: Diverse People, Diverse Career Needs.

    ERIC Educational Resources Information Center

    Kimbrough, Verna D.; Salomone, Paul R.

    1993-01-01

    Identifies the many subgroups within the African-American population and suggests guidelines for career counseling with different subcultures: rural and urban lower class, middle class, and underclass. (SK)

  18. Religious Coping Among African Americans, Caribbean Blacks and Non-Hispanic Whites

    PubMed Central

    Chatters, Linda M.; Taylor, Robert Joseph; Jackson, James S.; Lincoln, Karen D.

    2010-01-01

    This study examined demographic predictors of attitudes regarding religious coping (i.e., prayer during stressful times and look to God for support, strength and guidance) within a national sample of African American, Caribbean Blacks and non-Hispanic Whites (National Survey of American Life). The findings demonstrate significant Black-White differences in attitudes regarding religious coping with higher endorsements of religious coping among African Americans and Black Caribbeans (Caribbean Blacks). Comparisons of African Americans and Black Caribbeans revealed both similar and divergent patterns of demographic effects. For both African Americans and Black Caribbeans, women were more likely to utilize religious coping than men and married respondents were more likely than never married respondents to report utilizing prayer when dealing with a stressful situation. Further, for both groups, higher levels of education were associated with lower endorsements of the importance of prayer in dealing with stressful situations. Among African Americans only, Southerners were more likely than respondents who resided in other regions to endorse religious coping. Among Black Caribbeans, those who emigrated from Haiti were more likely than Jamaicans to utilize religious coping when dealing with a stressful episode. PMID:21048887

  19. A high-density admixture scan in 1,670 African Americans with hypertension.

    PubMed

    Deo, Rahul C; Patterson, Nick; Tandon, Arti; McDonald, Gavin J; Haiman, Christopher A; Ardlie, Kristin; Henderson, Brian E; Henderson, Sean O; Reich, David

    2007-11-01

    Hypertension (HTN) is a devastating disease with a higher incidence in African Americans than European Americans, inspiring searches for genetic variants that contribute to this difference. We report the results of a large-scale admixture scan for genes contributing HTN risk, in which we screened 1,670 African Americans with HTN and 387 control individuals for regions of the genome with elevated proportion of African or European ancestry. No loci were identified that were significantly associated with HTN. We also searched for evidence of an admixture signal at 40 candidate genes and eight previously reported linkage peaks, but none appears to contribute substantially to the differential HTN risk between African and European Americans. Finally, we observed nominal association at one of the loci detected in the admixture scan of Zhu et al. 2005 (p = 0.016 at 6q24.3 correcting for four hypotheses tested), although we caution that the significance is marginal and the estimated odds ratio of 1.19 per African allele is less than what would be expected from the original report; thus, further work is needed to follow up this locus. PMID:18020707

  20. A High-Density Admixture Scan in 1,670 African Americans with Hypertension

    PubMed Central

    Deo, Rahul C; Patterson, Nick; Tandon, Arti; McDonald, Gavin J; Haiman, Christopher A; Ardlie, Kristin; Henderson, Brian E; Henderson, Sean O; Reich, David

    2007-01-01

    Hypertension (HTN) is a devastating disease with a higher incidence in African Americans than European Americans, inspiring searches for genetic variants that contribute to this difference. We report the results of a large-scale admixture scan for genes contributing HTN risk, in which we screened 1,670 African Americans with HTN and 387 control individuals for regions of the genome with elevated proportion of African or European ancestry. No loci were identified that were significantly associated with HTN. We also searched for evidence of an admixture signal at 40 candidate genes and eight previously reported linkage peaks, but none appears to contribute substantially to the differential HTN risk between African and European Americans. Finally, we observed nominal association at one of the loci detected in the admixture scan of Zhu et al. 2005 (p = 0.016 at 6q24.3 correcting for four hypotheses tested), although we caution that the significance is marginal and the estimated odds ratio of 1.19 per African allele is less than what would be expected from the original report; thus, further work is needed to follow up this locus. PMID:18020707