Vertical distribution and radiative effects of mineral dust and biomass burning aerosol over West Africa during DABEX

This paper presents measurements of the vertical distribution of aerosol extinction coefficient over West Africa during the Dust and Biomass-burning Aerosol Experiment (DABEX)/African Monsoon Multidisciplinary Analysis dry season Special Observing Period Zero (AMMA-SOP0). In situ aircraft measurements from the UK FAAM aircraft have been compared with two ground-based lidars (POLIS and ARM MPL) and an airborne lidar on an ultralight aircraft. In general, mineral dust was observed at low altitudes (up to 2 km), and a mixture of biomass burning aerosol and dust was observed at altitudes of 2–5 km. The study exposes difficulties associated with spatial and temporal variability when intercomparing aircraft and ground measurements. Averaging over many profiles provided a better means of assessing consistent errors and biases associated with in situ sampling instruments and retrievals of lidar ratios. Shortwave radiative transfer calculations and a 3-year simulation with the HadGEM2-A climate model show that the radiative effect of biomass burning aerosol was somewhat sensitive to the vertical distribution of aerosol. In particular, when the observed low-level dust layer was included in the model, the absorption of solar radiation by the biomass burning aerosols increased by 10%. We conclude that this absorption enhancement was caused by the dust reflecting solar radiation up into the biomass burning aerosol layer. This result illustrates that the radiative forcing of anthropogenic absorbing aerosol can be sensitive to the presence of natural aerosol species.

The DACCIWA project: dynamics-aerosol-chemistry-cloud interactions in West Africa

Massive economic and population growth, and urbanization are expected to lead to a tripling of anthropogenic emissions in southern West Africa (SWA) between 2000 and 2030. However, the impacts of this on human health, ecosystems, food security, and the regional climate are largely unknown. An integrated assessment is challenging due to (a) a superposition of regional effects with global climate change, (b) a strong dependence on the variable West African monsoon, (c) incomplete scientific understanding of interactions between emissions, clouds, radiation, precipitation, and regional circulations, and (d) a lack of observations. This article provides an overview of the DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa) project. DACCIWA will conduct extensive fieldwork in SWA to collect high-quality observations, spanning the entire process chain from surface-based natural and anthropogenic emissions to impacts on health, ecosystems, and climate. Combining the resulting benchmark dataset with a wide range of modeling activities will allow (a) assessment of relevant physical, chemical, and biological processes, (b) improvement of the monitoring of climate and atmospheric composition from space, and (c) development of the next generation of weather and climate models capable of representing coupled cloud-aerosol interactions. The latter will ultimately contribute to reduce uncertainties in climate predictions. DACCIWA collaborates closely with operational centers, international programs, policy-makers, and users to actively guide sustainable future planning for West Africa. It is hoped that some of DACCIWA’s scientific findings and technical developments will be applicable to other monsoon regions.

Economic development and growth in West Africa: a multiple case study analysis of sovereign wealth funds’ investments and performance

Durante a recente crise da dívida soberana europeia, os fundos soberanos demonstraram seu peso na esfera financeira global. Contribuíram para salvar o sistema financeiro dos países desenvolvidos, distribuindo créditos que as entidades financeiras tradicionais do Norte não podiam mais providenciar. Em 2012, os ativos totais desses fundos atingiram USD 4.620 bilhões, comparado aos USD 3.355 bilhões de antes da crise, no final de 2007 (Preqin, 2012). Sendo quase todos criados por economias em desenvolvimento ou subdesenvolvidas, os fundos soberanos podem então ser vistos como o símbolo de um recente reequilíbrio do poder a favor desses países (Santiso, 2008). Além disso, em um futuro próximo, espera-se que os fundos soberanos afastem-se dos países desenvolvidos para investir mais em países em desenvolvimento. Nesse contexto, os países africanos estão cada vez mais alvos de investimentos dos fundos (Triki & Faye, 2011). O estudo subjacente analisa dois fundos, o IFC ALAC e o Mubadala Development Company, para entender como, de acordo com as percepções dos seus gestores, os fundos soberanos podem ajudar no desenvolvimento dos países beneficiários. Mais precisamente, trata-se definir, através de um estudo de casos múltiplos, quais são os mecanismos pelos quais os fundos soberanos podem impactar o desenvolvimento da África ocidental. Os resultados sugerem que, segundo os gestores, os fundos soberanos podem desempenhar um papel significativo no desenvolvimento dos países beneficiários. Eles investem em alguns setores-chave da economia (bancos, infraestruturas etc.), criando condições favoráveis ao desenvolvimento local. Além disso, através de um efeito multiplicador, os investimentos dos fundos soberanos alavancam novos investimentos do setor privado local ou global, fortalecendo o tecido industrial e produtivo do país beneficiário. Porém, parece que as empresas beneficiárias não ajudam nas transferências de conhecimento e de tecnologia, embora sejam essenciais para o desenvolvimento econômico, e se limitam a programas de treinamento específico e de RSE. Além disso, apesar dos investimentos de fundos soberanos impulsionarem o crescimento da região, eles também podem agravar a dependência dessas economias à exportação de commodities. Finalmente, os impactos positivos dos fundos soberanos sobre a economia regional são muitas vezes reduzidos devido a conflitos políticos e barreiras estruturais exigindo reformas profundas e de longo prazo.

Condom use at last sexual relationship among adolescents of Santiago Island, Cape Verde, - West Africa

Objective: To estimate factors associated with condom use at last sexual intercourse among adolescents.Methods: Cross-sectional study of a representative sample of 368 sexually active adolescents aged 13-17 years from eight public high schools on Santiago Island, Cape Verde, 2007. The level of significance was 5.0% obtained from logistic regression, considering the association between condom use and socio-demographic, sexual and reproductive variables.Results: The prevalence of condom use at last sexual intercourse was 94.9%. Factors associated with condom use at last sexual relationship were: non-Catholic religion (OR=0.68, 95%CI: 0.52; 0.88) and affective-sexual partnership before the interview (OR=5.15, 95%CI: 1.79; 14.80).Conclusions: There was a high prevalence of condom use at last sexual intercourse of adolescents.

Microsatellite analysis supports clonal propagation and reduced divergence of Trypanosoma vivax from asymptomatic to fatally infected livestock in South America compared to West Africa

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A Silent Enzootic of an Orthopoxvirus in Ghana, West Africa: Evidence for Multi-Species Involvement in the Absence of Widespread Human Disease

Human monkeypox has never been reported in Ghana, but rodents captured in forested areas of southern Ghana were the source of the monkeypox virus introduced into the United States in 2003. Subsequent to the outbreak in the United States, 204 animals were collected from two commercial trapping sites in Ghana. Animal tissues were examined for the presence of orthopoxvirus (OPXV) DNA using a real-time polymerase chain reaction, and sera were assayed for antibodies against OPXV. Animals from five genera (Cricetomys , Graphiurus , Funiscirus, and Heliosciurus ) had antibodies against OPXV, and three genera (Cricetomys , Graphiurus , and Xerus) had evidence of OPXV DNA in tissues. Additionally, 172 persons living near the trapping sites were interviewed regarding risk factors for OPXV exposure, and their sera were analyzed. Fifty-three percent had IgG against OPXV; none had IgM. Our findings suggest that several species of forest-dwelling rodents from Ghana are susceptible to naturally occurring OPXV infection, and that persons living near forests may have low-level or indirect exposure to OPXV-infected animals, possibly resulting in sub-clinical infections.

Condom use at last sexual relationship among adolescents of Santiago Island, Cape Verde, - West Africa

Objective: To estimate factors associated with condom use at last sexual intercourse among adolescents. Methods: Cross-sectional study of a representative sample of 368 sexually active adolescents aged 13-17 years from eight public high schools on Santiago Island, Cape Verde, 2007. The level of significance was 5.0% obtained from logistic regression, considering the association between condom use and socio-demographic, sexual and reproductive variables. Results: The prevalence of condom use at last sexual intercourse was 94.9%. Factors associated with condom use at last sexual relationship were: non-Catholic religion (OR=0.68, 95%CI: 0.52; 0.88) and affective-sexual partnership before the interview (OR=5.15, 95%CI: 1.79; 14.80). Conclusions: There was a high prevalence of condom use at last sexual intercourse of adolescents.

Adjusting mortality for loss to follow-up: analysis of five ART programmes in sub-Saharan Africa

Evaluation of antiretroviral treatment (ART) programmes in sub-Saharan Africa is difficult because many patients are lost to follow-up. Outcomes in these patients are generally unknown but studies tracing patients have shown mortality to be high. We adjusted programme-level mortality in the first year of antiretroviral treatment (ART) for excess mortality in patients lost to follow-up.

Rates and Predictors of Failure of First-line Antiretroviral Therapy and Switch to Second-line ART in South Africa

To measure rates and predictors of virologic failure and switch to second-line antiretroviral therapy (ART) in South Africa.

Prevalence and predictors of kaposi sarcoma herpes virus seropositivity: a cross-sectional analysis of HIV-infected adults initiating ART in Johannesburg, South Africa

Background Kaposi sarcoma (KS) is the most common AIDS-defining tumour in HIV-infected individuals in Africa. Kaposi sarcoma herpes virus (KSHV) infection precedes development of KS. KSHV co-infection may be associated with worse outcomes in HIV disease and elevated KSHV viral load may be an early marker for advanced HIV disease among untreated patients. We examined the prevalence of KSHV among adults initiating antiretroviral therapy (ART) and compared immunological, demographic and clinical factors between patients seropositive and seronegative for KSHV. Results We analyzed cross-sectional data collected from 404 HIV-infected treatment-naïve adults initiating ART at the Themba Lethu Clinic, Johannesburg, South Africa between November 2008 and March 2009. Subjects were screened at ART initiation for antibodies to KSHV lytic K8.1 and latent Orf73 antigens. Seropositivity to KSHV was defined as positive to either lytic KSHV K8.1 or latent KSHV Orf73 antibodies. KSHV viremia was determined by quantitative PCR and CD3, 4 and 8 lymphocyte counts were determined with flow cytometry. Of the 404 participants, 193 (48%) tested positive for KSHV at ART initiation; with 76 (39%) reactive to lytic K8.1, 35 (18%) to latent Orf73 and 82 (42%) to both. One individual presented with clinical KS at ART initiation. The KSHV infected group was similar to those without KSHV in terms of age, race, gender, ethnicity, smoking and alcohol use. KSHV infected individuals presented with slightly higher median CD3 (817 vs. 726 cells/mm3) and CD4 (90 vs. 80 cells/mm3) counts than KSHV negative subjects. We found no associations between KSHV seropositivity and body mass index, tuberculosis status, WHO stage, HIV RNA levels, full blood count or liver function tests at initiation. Those with detectable KSHV viremia (n = 19), however, appeared to present with signs of more advanced HIV disease including anemia and WHO stage 3 or 4 defining conditions compared to those in whom the virus was undetectable. Conclusions We demonstrate a high prevalence of KSHV among HIV-infected adults initiating ART in a large urban public-sector HIV clinic. KSHV viremia but not KSHV seropositivity may be associated with markers of advanced HIV disease.

Tenofovir in second-line ART in Zambia and South Africa: collaborative analysis of cohort studies

Tenofovir (TDF) is increasingly used in second-line antiretroviral treatment (ART) in sub-Saharan Africa. We compared outcomes of second-line ART containing and not containing TDF in cohort studies from Zambia and the Republic of South Africa (RSA).