Stratégie Long-Terme (LTS) de développement sobre en carbone et résilient aux changements climatiques dans le secteur de l’Agriculture : options de développement sobre en carbone et résilient

Conscient de cette situation de plus en plus préoccupante, le Gouvernement du Sénégal a considéré le Sous secteur de l’Agriculture comme une priorité dans sa Contribution Déterminée au niveau national (CDN). C’est presentation fournir des informations climatiques régionales à échelle réduite en utilisant les SSP (Shared Socio economic Pathways) pour développer des trajectoires de développement à long terme de l’agriculture, sobres en carbone et résilientes au climat pour le Sénégal

Características de la superficie terrestre y clima en África occidental: sesgos e impactos de los modelos de la deforestación histórica inducida antropogénicamente

Land Use Land-Cover Change (LULCC), such as deforestation, affects the climate system and land-atmosphere interactions. Using simulations carried out within the LUCID (Land Use and Climate, IDentification of robust Impacts) project framework, we first quantify the role of historical land-cover change induced by human activities on surface climate in West Africa. Focusing on two contrasted African regions, we find that climate responses of land-use changes are small but they are still statistically significant. In Western Sahel, a statistically significant near-surface atmospheric cooling and a decrease in water recycling are simulated in summer in response to LULCC. Over the Guinean zone, models simulate a significant decrease in precipitation and water recycling in autumn in response to LULCC. This signal is comparable in magnitude with the effect induced by the increase in greenhouse gases. Simulated climate changes due to historical LULCC could however be underestimated because: (i) the prescribed LULCC can be underestimated in those regions; (ii) the climate models underestimate the coupling strength between West African surface climate and leaf area index (LAI) and (iii) the lack of interactive LAI in some models. Finally, our study reveals indirect atmospheric processes triggered by LULCC. Over the Western Sahel, models reveal that a significant decrease in solar reflection tend to cool down the surface and thus counteract the atmospheric feedback. Conversely, over the Guinea zone, models reveal that the indirect atmospheric processes and turbulent heat fluxes dominate the climatic responses over the direct effects of LULCC

ARMC 5 Variants and Risk of Hypertension in Blacks: MH- GRID Study.

Background We recently found that ARMC 5 variants may be associated with primary aldosteronism in blacks. We investigated a cohort from the MH - GRID (Minority Health Genomics and Translational Research Bio-Repository Database) and tested the association between ARMC 5 variants and blood pressure in black s. Methods and Results Whole exome sequencing data of 1377 black s were analyzed. Target single-variant and gene-based association analyses of hypertension were performed for ARMC 5, and replicated in a subset of 3015 individuals of African descent from the UK Biobank cohort. Sixteen rare variants were significantly associated with hypertension ( P=0.0402) in the gene-based (optimized sequenced kernel association test) analysis; the 16 and one other, rs116201073, together, showed a strong association ( P=0.0003) with blood pressure in this data set. The presence of the rs116201073 variant was associated with lower blood pressure. We then used human embryonic kidney 293 and adrenocortical H295R cells transfected with an ARMC 5 construct containing rs116201073 (c.*920T>C). The latter was common in both the discovery ( MH - GRID ) and replication ( UK Biobank) data and reached statistical significance ( P=0.044 [odds ratio, 0.7] and P=0.007 [odds ratio, 0.76], respectively). The allele carrying rs116201073 increased levels of ARMC5 mRNA , consistent with its protective effect in the epidemiological data. Conclusions ARMC 5 shows an association with hypertension in black s when rare variants within the gene are considered. We also identified a protective variant of the ARMC 5 gene with an effect on ARMC 5 expression confirmed in vitro. These results extend our previous report of ARMC 5's possible involvement in the determination of blood pressure in blacks

Vector competence of Aedes vexans (Meigen), Culex poicilipes (Theobald) and Cx. quinquefasciatus Say from Senegal for West and East African lineages of Rift Valley fever virus

Background Rift Valley fever virus (RVFV; Phlebovirus, Bunyaviridae) is a mosquito–borne, zoonotic pathogen. In Senegal, RVFV was first isolated in 1974 from Aedes dalzieli (Theobald) and thereafter from Ae. fowleri (de Charmoy), Ae. ochraceus Theobald, Ae. vexans (Meigen), Culex poicilipes (Theobald), Mansonia africana (Theobald) and Ma. uniformis (Theobald). However, the vector competence of these local species has never been demonstrated making hypothetical the transmission cycle proposed for West Africa based on serological data and mosquito isolates. Methods Aedes vexans and Cx. poicilipes, two common mosquito species most frequently associated with RVFV in Senegal, and Cx. quinquefasciatus, the most common domestic species, were assessed after oral feeding with three RVFV strains of the West and East/central African lineages. Fully engorged mosquitoes (420 Ae. vexans, 563 Cx. quinquefasciatus and 380 Cx. poicilipes) were maintained at 27 ± 1 °C and 70–80 % relative humidity. The saliva, legs/wings and bodies were tested individually for the RVFV genome using real-time RT-PCR at 5, 10, 15 and 20 days post exposure (dpe) to estimate the infection, dissemination, and transmission rates. Genotypic characterisation of the 3 strains used were performed to identify factors underlying the different patterns of transmission. Results The infection rates varied between 30.0–85.0 % for Ae. vexans, 3.3–27 % for Cx. quinquefasciatus and 8.3–46.7 % for Cx. poicilipes, and the dissemination rates varied between 10.5–37 % for Ae. vexans, 9.5–28.6 % for Cx. quinquefasciatus and 3.0–40.9 % for Cx. poicilipes. However only the East African lineage was transmitted, with transmission rates varying between 13.3–33.3 % in Ae. vexans, 50 % in Cx. quinquefasciatus and 11.1 % in Cx. poicilipes. Culex mosquitoes were less susceptible to infection than Ae. vexans. Compared to other strains, amino acid variation in the NSs M segment proteins of the East African RVFV lineage human-derived strain SH172805, might explain the differences in transmission potential. Conclusion Our findings revealed that all the species tested were competent for RVFV with a significant more important role of Ae. vexans compared to Culex species and a highest potential of the East African lineage to be transmitted

Climatology of radar anomalous propagation over West Africa

KAISSASSOU Samuel Abstract A comprehensive examination of 5 years of European Centre for Medium-Range Weather Forecasts (ECMWF) data to determine ducting conditions over West Africa and the computation of statistical distributions of the vertical gradient of refractivity determined from 2 years of radiosonde data over Dakar (14.41°N, 17.26°W), Douala (4.00°N, 9.70°E) and Niamey (13.35°N, 2.03°E) were carried out. It is found that diurnal and seasonal variations of the refractivity of the atmosphere are influenced by air temperature and water vapor pressure fluctuation. Refractivity gradients lower than -0.157 m -1 often result in spurious returned echoes and misinterpretation of radar images such as erroneous precipitation detection. The results obtained show that the local climate has an appreciable influence on the vertical profile of refractivity, especially the seasonal north-south movement of the Inter Tropical Discontinuity which is associated with the alternance of wet and dry seasons over the region. It is found that most of ducts occur in the night, morning (0000, 0600 UTC) and late afternoon (1800 UTC). The occurrence probability of abnormal propagation events, such as ducts, can provide some valuable information about the propagation of electromagnetic waves over West Africa

Impact of the Madden Julian Oscillation on the summer West African monsoon in AMIP simulations

At intraseasonal timescales, convection over West Africa is modulated by the Madden Julian Oscillation (MJO). In this work we investigate the simulation of such relationship by 11 state-of-the-art atmospheric general circulation models runs with prescribed observed sea surface temperatures. In general, the Atmospheric Model Intercomparison Project simulations show good skill in capturing the main characteristics of the summer MJO as well as its influence on convection and rainfall over West Africa. Most models simulate an eastward spatiotemporal propagation of enhanced and suppressed convection similar to the observed MJO, although their signal over West Africa is weaker in some models. In addition, the ensemble average of models' composites gives a better performance in reproducing the main features and timing of the MJO and its impact over West Africa. The influence on rainfall is well captured in both Sahel and Guinea regions thereby adequately producing the transition between positive and negative rainfall anomalies through the different phases as in the observations. Furthermore, the results show that a strong active convection phase is clearly associated with a stronger African Easterly Jet (AEJ) but the weak convective phase is associated with a much weaker AEJ. Our analysis of the equatorial waves suggests that the main impact over West Africa is established by the propagation of low-frequency waves within the MJO and Rossby spectral peaks. Results from the simulations confirm that it may be possible to predict anomalous convection over West Africa with a time lead of 15-20 day

Land-surface characteristics and climate in West Africa : Models’ biases and impacts of historical anthropogenically-induced deforestation

Land Use Land-Cover Change (LULCC), such as deforestation, affects the climate system and land-atmosphere interactions. Using simulations carried out within the LUCID (Land Use and Climate, IDentification of robust Impacts) project framework, we first quantify the role of historical land-cover change induced by human activities on surface climate in West Africa. Focusing on two contrasted African regions, we find that climate responses of land-use changes are small but they are still statistically significant. In Western Sahel, a statistically significant near-surface atmospheric cooling and a decrease in water recycling are simulated in summer in response to LULCC. Over the Guinean zone, models simulate a significant decrease in precipitation and water recycling in autumn in response to LULCC. This signal is comparable in magnitude with the effect induced by the increase in greenhouse gases. Simulated climate changes due to historical LULCC could however be underestimated because: (i) the prescribed LULCC can be underestimated in those regions; (ii) the climate models underestimate the coupling strength between West African surface climate and leaf area index (LAI) and (iii) the lack of interactive LAI in some models. Finally, our study reveals indirect atmospheric processes triggered by LULCC. Over the Western Sahel, models reveal that a significant decrease in solar reflection tend to cool down the surface and thus counteract the atmospheric feedback. Conversely, over the Guinea zone, models reveal that the indirect atmospheric processes and turbulent heat fluxes dominate the climatic responses over the direct effects of LULCC

Forage resources and animals’ feeding in southern groudnut bassin and eastern regions of Senegal

Rainfall disturbances, a consequence of the effects of climate change, aggravated by anthropogenic pressure on vegetation, are leading to the progressive disappearance of several adapted local plant species in the so-called "groundnut basin" and eastern Senegal. Also, the clearing of land for agriculture potentiates and amplifies this degradation. At this rate, the loss of most of the local plant, forage and forest resources will follow. As part of a multi-species census and collection of plant genetic resources for food and agriculture, an inventory of available forage resources in the groundnut basin and eastern Senegal was made. This inventory was made by field observations triangulated with interview data. The results show that the methods and level of exploitation of natural forage resources and crop residues differ from one area to another. The natural rangeland, which still constitutes the essential part of domestic ruminants feed in these regions, is in continuous degradation. In fact, this rangeland in groundnut basin is not very diversified like southern area, with a low index of quality and volume of pastures. Crop residues are abundant but not very varied. They represent an interest for the breeders of this zone and their sale prices can sometimes exceed those of the harvested products. This is a snapshot of the situation, valid for a given time. This situation is dynamic and can change significantly from one moment to the next. Nevertheless, the results obtained will make it possible to conceive methods of conservation and production of the identified species; in order to identify the best methods of management and sustainable use

Le pneumothorax spontané comme une manifestation évolutive de la polyarthrite rhumatoide: à propos d’une observation clinique et revue de la litterature

La polyarthrite rhumatoïde est une maladie systémique inflammatoire caractérisée par une destruction des synoviales articulaires et des lésions systémiques extra articulaires. Les nodules pulmonaires font partie de ces dernières. Leur évolution peut aboutir à un pneumothorax spontané. Nous rapportons le cas d'un adulte jeune au long passé de polyarthrite rhumatoïde qui a présenté deux épisodes de pneumothorax spontané. Il était admis dans notre service, en urgence, pour un pneumothorax droit spontané et massif sur terrain de polyarthrite rhumatoïde au stade de déformation. Il était sous méthotrexate. La radiographie standard du thorax et la tomodensitométrie montraient un décollement pleural complet droit, des nodules et des images excavées sur les deux champs pulmonaires. Il a bénéficié d'un drainage thoracique aspiratif permettant une bonne ré-expansion pulmonaire. Le pneumothorax spontané constitue une manifestation rare des lésions pulmonaire de la polyarthrite rhumatoïde. Il s'agit le plus souvent d'une manifestation évolutive de la maladie mais aussi une circonstance de découverte de cette dernière. L'implication des immunosuppresseurs reste à être prouvée. Ainsi la polyarthrite rhumatoïde doit être considérée dans la recherche étiologique d'un pneumothorax spontané.Pan African Medical Journal 2015; 2