Effect of junction quality on the performance of a silicon solar cell

In this work, a modeling study of the effect of the junction quality on the performance of a silicon solar cell is presented. Based on a one dimensional modeling of the solar cell, the continuity equation of excess minority carriers is solved with boundary conditions taking into account the intrinsic junction recombination velocity and led to analytical expressions of photocurrent density, photovoltage and electric power. The effect of the intrinsic junction recombination velocity or the solar cell junction quality on photocurrent, photovoltage and electric power, is exhibited and we determine the maximum electric power, the junction dynamic velocity at the maximum power point and the conversion efficiency according to the junction quality of the solar cell. From the electric power lost at the junction, we calculated the shunt resistance of the solar cell according to the junction quality.Keywords: Efficiency; Intrinsic junction recombination velocity; Joule effect; Solar cell; Shunt resistanc

Potential use of clay from Burkina Faso as filler in rubber production

raw clay materials deposit in Burkina Faso have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and chemical analysis to evaluate their potentialities to be used in rubber compounds production as filler. The samples are composed principally by aolinite, illite and quartz. The rubber compounds have been done in open two-roll mill at room temperature and tested for cure characteristic (ts5, tc90), ineralogical composition by XRD, microstructure by SEM and mechanical properties (Elongation at break, Tear strength, tensile strength, hardness shore A and modulus). The cure characteristics of the rubber compounds formulated with the sample are feeble than those made with commercial kaolin (control). The mechanical properties are in general, except the longation at break, for the sample lowest than those of control. However the different values obtained with the sample are not far to those obtained with commercial kaolin. The different samples can then be used as filler in rubber production after a pre-treatment to reduce the impurities.Keywords: Raw clay materials, rubber, rheology

Possibilités de bouturage chez Maerua crassifolia Forssk., Capparaceae, un ligneux fourrager Sahélien

Possibilities of propagation by cutting at maerua crassifolia forssk.,capparaceae, a sahelian fodder tree Characteristics of the cutting of Maerua crassifolia, a sahelian fodder tree, and their monthly variations were established with cuttings resulting from plantations obtained byartificial regeneration. On a branch of stem, we distinguished closed, median and distant parts. Work took place during hot dry period, in May, April, June and July. The time of resumption is the same one for the various types of cuttings in April. For this month, the most elevated resumption rate (86.70 %) has been gotten with closed cuttings with a length of 19 days of resumption. The weakest resumption rate has been raised to themonth of May, in spite of a length of 9 days of resumption. The month of July, with 91.30 % of resumption and a length of 19 days appears most auspicious. In the same way the delay of resumption was of 2 days

Outcome of a workshop

International audience; In tackling agricultural challenges, policy-makers in sub-Saharan Africa (SSA) have increasingly considered genetically modified (GM) crops as a potential tool to increase productivity and to improve product quality. Yet, as elsewhere in the world, the adoption of GM crops in SSA has been marked by controversy, encompassing not only the potential risks to animal and human health, and to the environment, but also other concerns such as ethical issues, public participation in decision-making, socio-economic factors and intellectual property rights. With these non-scientific factors complicating an already controversial situation, disseminating credible information to the public as well as facilitating stakeholder input into decision-making is essential. In SSA, there are various and innovative risk communication approaches and strategies being developed, yet a comprehensive analysis of such data is missing. This gap is addressed by giving an overview of current strategies, identifying similarities and differences between various country and institutional approaches and promoting a way forward, building on a recent workshop with risk communicators working in SSA

Falciparum malaria in young children of rural Burkina Faso: comparison of survey data in 1999 with 2009

<p>Abstract</p> <p>Background</p> <p>Roll Back Malaria (RBM) interventions such as insecticide-treated mosquito nets (ITN) and artemisinin-based combination therapy (ACT) have become implemented with different velocities in the endemic countries of sub-Saharan Africa (SSA) in recent years. There is conflicting evidence on how much can be achieved under real life conditions with the current interventions in the highly endemic savannah areas of SSA.</p> <p>Methods</p> <p>The study took place in a rural area of north-western Burkina Faso, which was defined as holoendemic in 1999. Clinical and parasitological data were compared in two cohorts of young children of the same age range from eight villages. Surveys took place in June and December of the year 1999 and 2009 respectively.</p> <p>Results</p> <p>Prevalence of mosquito net use increased from 22% in 1999 to 73% in 2009, with the majority of nets being ITNs in 2009. In 2009, <it>P. falciparum </it>prevalence was significantly lower compared to 1999 (overall reduction of 22.8%).</p> <p>Conclusions</p> <p>The reduction in malaria prevalence in young children observed between 1999 and 2009 in a rural and formerly malaria holoendemic area of Burkina Faso is likely attributable to the increase in ITN availability and utilization over time.</p

A cost-effectiveness study of caesarean-section deliveries by clinical officers, general practitioners and obstetricians in Burkina Faso

<p>Abstract</p> <p>Background</p> <p>The aim of this paper was to evaluate the effectiveness and cost-effectiveness of alternative training strategies for increasing access to emergency obstetric care in Burkina Faso.</p> <p>Methods</p> <p>Case extraction forms were used to record data on 2305 caesarean sections performed in 2004 and 2005 in hospitals in six out of the 13 health regions of Burkina Faso. Main effectiveness outcomes were mothers' and newborns' case fatality rates. The costs of performing caesarean sections were estimated from a health system perspective and Incremental Cost-Effectiveness Ratios were computed using the newborn case fatality rates.</p> <p>Results</p> <p>Overall, case mixes per provider were comparable. Newborn case fatality rates (per thousand) varied significantly among obstetricians, general practitioners and clinical officers, at 99, 125 and 198, respectively. The estimated average cost per averted newborn death (x 1000 live births) for an obstetrician-led team compared to a general practitioner-led team was 11 757 international dollars, and for a general practitioner-led team compared to a clinical officer-led team it was 200 international dollars. Training of general practitioners appears therefore to be both effective and cost-effective in the short run. Clinical officers are associated with a high newborn case fatality rate.</p> <p>Conclusion</p> <p>Training substitutes is a viable option to increase access to life-saving operations in district hospitals. The high newborn case fatality rate among clinical officers could be addressed by a refresher course and closer supervision. These findings may assist in addressing supply shortages of skilled health personnel in sub-Saharan Africa.</p

Prevalence and correlates of partner violence among adolescent girls and young women: Evidence from baseline data of a cluster randomised trial in Tanzania.

BACKGROUND: Little has been documented about partner violence among adolescent girls and young women (AGYW) who are out of school, a factor associated with HIV acquisition. To understand areas for prioritising HIV prevention intervention efforts, we explored the prevalence and correlates of partner violence among out of school AGYW in Shinyanga, Tanzania. METHODS: A cross-sectional analysis of data from AGYW aged 15-23 years recruited in a cluster randomised trial conducted between October and December 2017 was used to examine correlates of partner violence. Data were collected through an Audio Computer-Assisted Self-interview. Multivariate logistic regression analysis was used to evaluate the association. RESULTS: 2276 (75.5%) AGYW were sexually active. Of these, 816 (35.9%) reported having experienced violence from partners in the last six months. After adjusting for other covariates, being formerly married (AOR = 1.55, 95% CI:1.02, 2.37), having children (AOR = 1.79, 95% CI:1.47, 2.16), anxiety and depression symptoms (AOR = 3.27, 95%CI: 2.15, 4.96), having engaged in sex work in the past six months (AOR = 1.92, 95% CI: 1.45, 2.53) and economic deprivation (AOR = 1.61, 95% CI: 1.34,1.92) were significantly associated with partner violence. CONCLUSIONS: Almost one in three sexually active AGYW had experienced partner violence in the 6 months preceding the survey. The findings underscore the need for future research to focus on understanding the reasons and dynamics underlying high level of partner violence among AGYW. Furthermore, there is a need for implementing intervention programs that aim to reduce economic deprivation among AGYWs and address social norms and structures perpetuating violence against AGYW. TRIAL REGISTRATION: ClinicalTrials.gov-ID NCT03597243

West African Cattle Farmers’ Perception of Tick-Borne Diseases

Worldwide, cattle production is struggling to face the negative impacts caused by ticks and Rhipicephalus (Boophilus) microplus is one of the most harmful ticks for livestock. Most of the people in West Africa depend on cattle farming and subsistence agriculture. The presence of ticks on cattle is a major problem faced by smallholder farmers who fight for their livelihood. National and regional tick control programs could assist these rural communities in protecting their livelihoods against ticks and tick-borne diseases, but only if they take into account the targeted herders and their perception on cattle management and tick control. This paper aims to provide a better insight in the socio-economic characteristics of Beninese cattle farmers, and their perception on tick burden, as well as to document common tick control strategies. Different tick species and their seasonality are well understood by cattle herders. For tick control, many still use manual tick removal, especially in the north of the country. The high cost of acaricides, the lack of financial means of African farmers, and of the local stockbreeders in particular, limits the use of acaricides in livestock breeding in Benin. While aiming to increase the meat or milk production of their animals, stockbreeders who can afford it sometimes turn to an abusive use of acaricides, which might in time lead to an increase in tick resistance. This study remains one of the rare studies to report extensively on the perceptions of West African cattle herders

New Antenatal Model in Africa and India (NAMAI) study: implementation research to improve antenatal care using WHO recommendations

Background: In 2020, an estimated 287 000 women died globally from pregnancy‐related causes and 2 million babies were stillborn. Many of these outcomes can be prevented by quality healthcare during pregnancy and childbirth. Within the continuum of maternal health, antenatal care (ANC) is a key moment in terms of contact with the health system, yet it remains an underutilized platform. This paper describes the protocol for a study conducted in collaboration with Ministries of Health and country research partners that aims to employ implementation science to systematically introduce and test the applicability of the adapted WHO ANC package in selected sites across four countries. Methods: Study design is a mixed methods stepped-wedge cluster randomized implementation trial with a nested cohort component (in India and Burkina Faso). The intervention is composed of two layers: (i) the country- (or state)-specific ANC package, including evidence-based interventions to improve maternal and newborn health outcomes, and (ii) the co-interventions (or implementation strategies) to help delivery and uptake of the adapted ANC package. Using COM-B model, co-interventions support behaviour change among health workers and pregnant women by (1) training health workers on the adapted ANC package and ultrasound (except in India), (2) providing supplies, (3) conducting mentoring and supervision and (4) implementing community mobilization strategies. In Rwanda and Zambia, a fifth strategy includes a digital health intervention. Qualitative data will be gathered from health workers, women and their families, to gauge acceptability of the adapted ANC package and its components, as well as experience of care. The implementation of the adapted ANC package of interventions, and their related costs, will be documented to understand to what extent the co-interventions were performed as intended, allowing for iteration. Discussion: Results from this study aim to build the global evidence base on how to implement quality ANC across different settings and inform pathways to scale, which will ultimately lead to stronger health systems with better maternal and perinatal outcomes. On the basis of the study results, governments will be able to adopt and plan for national scale-up, aiming to improve ANC nationally. This evidence will inform global guidance. Trial registration number: ISRCTN, ISRCTN16610902. Registered 27 May 2022. https://www.isrctn.com/ISRCTN16610902