This research work focuses on the problem of climate simulation of rainfall over West Africa and particularly over coastal countries of the Gulf of Guinea by Regional Climate Models. The ...sensitivities of Weather Research and Forecasting (WRF) Model were tested for changes in horizontal resolution (convection permitting versus parameterized) on the replication of West African monsoon for the year 2014. Sensitivity test was also performed for response of rainfall to changes in microphysics (MP) and planetary boundary layer (PBL) schemes. Generally, the result shows that WRF is able to replicates rainfall distribution with an adequate representation of the dynamical features of West African monsoon system. The high-resolution (wrf-4km) shows dry bias along the coast of the Gulf of Guinea but generally outperforms wrf-24km run especially in replication of the extreme rainfall distribution. The dry bias along the coastal area is suggested to not to be only related to convection but mostly to microphysics and PBL parameterisation schemes. Differences were noticed between the dynamics of WRF and ERA-interim outputs despite the use of spectral nudging in the experiment which then suggest strong interactions between scales. These differences were observed to be restricted mainly to the low-layer monsoon flow in JJA. Both runs at 24 and 4 km hardly simulate the typical diurnal distribution of rainfall. The sensitivity of WRF to MP (only sophisticated MP were tested) and PBL reveals a stronger impact of PBL than MP on rainfall distribution and the most significant added value over the Guinean coast and surroundings area was provided by the configurations using non-local PBL scheme (as ACM2). The changes in MP and PBL schemes in general seem to have less effect on the explicit runs (wrf-4km) in the replication of the rainfall over the Gulf of Guinea and the surroundings seaboard.
Perennial malaria chemoprevention (PMC) aims to protect children at risk from severe malaria by the administration of anti-malarial drugs to children of defined ages throughout the year. ...Sulfadoxine-pyrimethamine (SP) has been widely used for chemoprevention in Africa and a child-friendly dispersible tablet formulation has recently become available.
This qualitative non-interventional observational study was conducted in Benin, Côte d'Ivoire, and Mozambique between February and June 2022. Prototype blister packs, dispensing boxes and job aids designed to support dispersible SP deployment for PMC were evaluated using focus group discussions (FGD) and semi-structured in-depth individual interviews (IDI) with health authorities, health personnel, community health workers (CHWs) and caregivers. The aim was to evaluate knowledge and perceptions of malaria and chemoprevention, test understanding of the tools and identify gaps in understanding, satisfaction, user-friendliness and acceptability, and assess the potential role of CHWs in PMC implementation. Interviews were transcribed and imported to ATLAS.ti for encoding and categorization. Thematic content analysis used deductive and inductive coding with cross-referencing of findings between countries and participants to enrich data interpretation. Continuous comparison across the IDI and FGD permitted iterative, collaborative development of materials.
Overall, 106 participants completed IDIs and 70 contributed to FGDs. Malaria was widely recognised as the most common disease affecting children, and PMC was viewed as a positive intervention to support child health. The role of CHWs was perceived differently by the target groups, with caregivers appreciating their trusted status in the community, whereas health authorities preferred clinic-based deployment of PMC by health professionals. Empirical testing of the prototype blister packs, dispensing boxes and job aids highlighted the context-specific expectations of respondents, such as familiar situations and equipment, and identified areas of confusion or low acceptance. A key finding was the need for a clear product identity reflecting malaria.
Simple modifications profoundly affected the perception of PMC and influenced acceptability. Iterative quantitative investigation resulted in PMC-specific materials suited to the local context and socio-cultural norms of the target population with the aim of increasing access to chemoprevention in children most at risk of severe malaria.
The decomposition of an inert body seems to depend on the physiological, biological and physical characteristics of the corpse. The effect of these, especially of extra-biological mechanisms, on the ...rate of decomposition of the corpse does not seem to be sufficiently explored. The present work proposes to examine the influence of the type of feeding on the rate of cadaver decomposition in a human surrogate. It is based on a sample of four corpses of juvenile male pigs of the species
Sus scrofa domesticus
, three of which are experimental and one is a control aged 12 weeks and having a mass between 19 and 24 kg. The three experimental pigs were fed an energetic, construction and functional diet respectively. The control was fed a general diet. These different carcasses are exposed to the open air on four similar sites. The experiment is repeated twice, according to the protocol that guided the initial experiment conducted on comparable sites (eight cadavers, six experimental and two control). The measurement of the pigs’ diet was done through a questionnaire. The mass of the decomposing carcass was explored by a specific tool, in this case, the weighing device. The results show that the rate of decomposition of the cadaver of pigs fed a general diet is higher than that of the cadavers of their counterparts fed construction, functional or energy diets. The type of diet would therefore influence the rate of decomposition of the cadaver of a human surrogate.
We examine the impact of +1.5 °C and +2 °C global warming levels above pre-industrial levels on consecutive dry days (CDD) and consecutive wet days (CWD), two key indicators for extreme precipitation ...and seasonal drought. This is done using climate projections from a multi-model ensemble of 25 regional climate model (RCM) simulations. The RCMs take boundary conditions from ten global climate models (GCMs) under the RCP8.5 scenario. We define CDD as the maximum number of consecutive days with rainfall amount less than 1 mm and CWD as the maximum number of consecutive days with rainfall amount more than 1 mm. The differences in model representations of the change in CDD and CWD, at 1.5 °C and 2 °C global warming, and based on the control period 1971−2000 are reported. The models agree on a noticeable response to both 1.5 °C and 2 °C warming for each index. Enhanced warming results in a reduction in mean rainfall across the region. More than 80% of ensemble members agree that CDD will increase over the Guinea Coast, in tandem with a projected decrease in CWD at both 1.5 °C and 2 °C global warming levels. These projected changes may influence already fragile ecosystems and agriculture in the region, both of which are strongly affected by mean rainfall and the length of wet and dry periods.
Over the past decades, large variations of precipitation were observed in Africa, which often led to dramatic consequences for local society and economy. To avoid such disasters in the future, it is ...crucial to better anticipate the expected changes, especially in the current context of climate change and population growth. To this date, however, projections of precipitation over Africa are still associated with very large uncertainties. To better understand how this uncertainty can be reduced, this study uses an advanced Bayesian analysis of variance (ANOVA) method to characterize, for the first time in the regional climate projections of CORDEX-AFRICA, the different sources of uncertainty associated with the projections of precipitation over Africa.
By 2090, the ensemble mean precipitation is projected to increase over the Horn of Africa from September to May and over the eastern Sahel and Guinea Coast from June to November. It is projected to decrease over the northern coast and southern Africa all year long, over western Sahel from March to August, and over the Sahel and Guinea Coast from March to May. Most of these projections however are not robust, i.e., the magnitude of change is smaller than the associated uncertainty. Over time, the relative contribution of internal variability (excluding interannual variability) to total uncertainty is moderate and quickly falls below 10%. By 2090, it is found that over the Horn of Africa, northern coast, southern Africa, and Sahel, most of the uncertainty results from a large dispersion across the driving Global Climate Models (in particular MIROC, CSIRO, CCCma, and IPSL), whereas over the tropics and parts of eastern Africa, most of the uncertainty results from a large dispersion across Regional Climate Models (in particular CLMcom).
This study aims to provide improved knowledge and evidence on current (1986–2015) climate variation based on six rainfall indices over five West African countries (Senegal, Niger, Burkina Faso, Ivory ...Coast, and Benin) using the Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) dataset. On average, precipitation has increased over the central Sahel and the western Sahel. This increase is associated with increase in the number of rainy days, longer wet spells and shorter dry spells. Over the Guinea Coast, the slight increase in precipitation is associated with an increase in the intensity of rainfall with a shorter duration of wet spells. However, these mean changes in precipitation are not all statistically significant and uniform within a country. While previous studies are focused on regional and sub-regional scales, this study contributes to deliver a climate information at a country level that is more relevant for decision making and for policy makers, and to document climate-related risks within a country to feed impact studies in key sectors of the development, such as agriculture and water resources.
This paper elucidates the phytoremediation potential of water hyacinth and water lettuce on the reduction of wastewater toxicity. Acute toxicity tests were performed in an aquarium with a population ...of Sarotherodon melanotheron , contaminated by different concentrations of wastewaters before and after phytoremediation with Eichhornia crassipes and Pistia stratiotes . Lethal concentrations (LC â â) of the fish's population obtained during 24 hours of exposures were determined. COD, BOD, ammonium, TKN and PO â³⻠concentrations in wastewaters were of 1850.29, 973.33, 38.34, 61.49 and 39.23 mg L â»Â¹, respectively, for each plant. Phytoremediation reduced 58.87% of ammonium content, 50.04% of PO â³â», 82.45% of COD and 84.91% of BOD. After 15 days of the experiment, metal contents in treated wastewaters decreased from 6.65 to 97.56% for water hyacinth and 3.51 to 93.51% for water lettuce tanks. Toxicity tests showed that the mortality of fish exposed increased with increase in concentration of pollutants in wastewaters and the time of exposure. Therefore, the highest value of LC â â was recorded for fish subjected to 3 hours of exposure (16.37%). The lowest rate was obtained after an exposure of 20 to 24 hours (5.85%). After phytoremediation, the effluents purified by Eichhornia crassipes can maintain the fish life beyond 24 hours of exposure.
The availability of water resources in a reservoir for electricity generation is strongly linked to climate and weather conditions. Also, the use of these water resources is influenced by the ...population size as well as anthropogenic activities. This research attempts to assess the combined effects of (i) climate change (CC), (ii) land use/land cover change (LULCC), and (iii) development (Dev) conditions on water resources and hydropower generation (HPGen) using Regional Climate Models (RCMs) from Coordinated Regional Downscaling Experiment (CORDEX) under the Representative Concentrated Pathways (RCP): RCP4.5 and RCP8.5. The RCMs considered are: CanRCM, CCLM, and WRF being drived by CanESM2, CNRM-CERFACS, and NorESM1, respectively. The Water Evaluation and Planning model (WEAP) tool is used to simulate the water availability and HPGen in the Mono basin under present and future conditions. The ensemble mean of the three-climate dataset analysis reveals that the temperature is projected to increase significantly while the precipitation change is uncertain under both RCPs in the near (2020–2050) and the far (2070–2090) futures. These changes in climate variables consequently affected simulated water availability for different water consumption sectors especially the HPGen in the near and far futures. Moreover, the Dev was found to exacerbate the burden that constitutes the CC for water availability and HPGen. Nevertheless, LULCC associated with either CC or both CC and Dev were projected by all the RCMs and their ensemble mean to reduce this burden. However, its side effects namely reservoir siltation and sedimentation need to be deeply investigated.
The 10-year observations of the atmospheric molar fractions of CO
2
, CH
4
and CO in West Africa were analyzed using a high precision measurement of the Lamto (LTO) station (6°31 N and 5°02 W) in ...Côte d'Ivoire. At daily scale, high concentrations appear at night with significant peaks around 7 a.m. local time and minimum concentrations in the afternoon for CO
2
and CH
4
. The CO concentrations show two peaks around 8 h and 20 h corresponding to the maximum in road traffic of a northern motorway located 14 km from the station. The long-term increase rates of CH
4
(∼7 ppb year
−1
) and CO
2
(∼2.24 ppm year
−1
) at Lamto are very close to global trends. The variations of the concentrations of the three gases show strong seasonality with a peak in January for all gases and minima in September for CO
2
and CH
4
, and in June for CO. The CO variation suggests a significant impact of fires on the CO, CO
2
and CH
4
anomalies in the Lamto region during the dry season (December to February). CO and CH
4
show strong correlations (at synoptic-scale and monthly based) in January (r = 0.84), February (r = 0.90), April (r = 0.74), November (r = 0.79) and December (r = 0.72) reflecting similar sources of emission for both gases. The trajectories of polluted air masses at LTO, also indicate continental sources of emission associated with Harmattan winds.
We assessed the effect of HIV status disclosure on retention in care from initiation of antiretroviral therapy (ART) among HIV-infected children aged 10 years or more in Cote d'Ivoire, Mali and ...Sénégal.
Multi-centre cohort study within five paediatric clinics participating in the IeDEA West Africa collaboration. HIV-infected patients were included in this study if they met the following inclusion criteria: aged 10-21 years while on ART; having initiated ART ≥ 200 days before the closure date of the clinic database; followed ≥ 15 days from ART initiation in clinics with ≥ 10 adolescents enrolled. Routine follow-up data were merged with those collected through a standardized ad hoc questionnaire on awareness of HIV status. Probability of retention (no death or loss-to-follow-up) was estimated with Kaplan-Meier method. Cox proportional hazard model with date of ART initiation as origin and a delayed entry at date of 10th birthday was used to identify factors associated with death or loss-to-follow-up.
650 adolescents were available for this analysis. Characteristics at ART initiation were: median age of 10.4 years; median CD4 count of 224 cells/mm³ (47% with severe immunosuppression), 48% CDC stage C/WHO stage 3/4. The median follow-up on ART after the age of 10 was 23.3 months; 187 adolescents (28.8%) knew their HIV status. The overall probability of retention at 36 months after ART initiation was 74.6% (95% confidence interval CI: 70.5-79.0) and was higher for those disclosed compared to those not: adjusted hazard ratio for the risk of being death or loss-to-follow-up = 0.23 (95% CI: 0.13-0.39).
About 2/3 of HIV-infected adolescents on ART were not aware of their HIV status in these ART clinics in West Africa but disclosed HIV status improved retention in care. The disclosure process should be thus systematically encouraged and organized in adolescent populations.
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