The Behavioral Determinants of Intestinal Schistosomiasis Transmission: Water Contact, Hygienic Practices and Risk Prevention. A study in Northern Senegal

Schistosomiasis (bilharzia) is one of the major parasitic diseases in the world, ranking second only to malaria in terms of its socio-economic and public health importance in tropical and subtropical areas (WHO, 1985; WHO, 2002). At least 200 million people are infected and 600 million at risk. An estimated 85% of all cases occur in Africa. Schistosomiasis is caused by infection with blood-dwelling fl uke worms (trematodes) of the genus Schistosoma. These are transmitted by fresh water snails and contracted through the skin during water contact. Humans can be infected by fi ve different species of the parasite, each of which has its own characteristics and effects. Except where mentioned differently, this thesis considers S. mansoni, the parasite of intestinal schistosomiasis in Northern Senegal

Variations in agronomic and grain quality traits of rice grown under irrigated lowland conditions in West Africa

Rice breeding in West Africa has been largely skewed toward yield enhancement and stress tolerance. This has led to the variable grain quality of locally produced rice in the region. This study sought to assess variations in the agronomic and grain quality traits of some rice varieties grown in this region, with a view to identifying sources of high grain yield and quality that could serve as potential donors in their breeding programs. Forty‐five varieties were grown under irrigated conditions in Benin and Senegal with two trials in each country. There were wide variations in agronomic and grain quality traits among the varieties across the trials. Cluster analysis using paddy yield, head rice yield, and chalkiness revealed that 68% of the total variation could be explained by five varietal groupings. One group comprising seven varieties (Afrihikari, BG90‐2, IR64, Sahel 108, WAT311‐WAS‐B‐B‐23‐7‐1, WAT339‐TGR‐5‐2, and WITA 10) had high head rice yield and low chalkiness. Of the varieties in this group, Sahel 108 had the highest paddy yield in three of the four trials. IR64 and Afrihikari had intermediate and low amylose content, respectively, with the rest being high‐amylose varieties. Another group of varieties consisting of B6144F‐MR‐6‐0‐0, C74, IR31851‐96‐2‐3‐2‐1, ITA222, Jaya, Sahel 305, WITA 1, and WITA 2 had high paddy yield but poor head rice yield and chalkiness. The use of materials from these two groups of varieties could accelerate breeding for high yielding rice varieties with better grain quality for local production in West Africa

Analyse des effects de la pluviometrie sur le PIB Agricole au Senegal

RESUMELe secteur agricole au Sénégal est dominé par les cultures pluviales dont l’arachide et le mil qui occupent la majeure partie des terres cultivables en hivernage. Sa contribution au PIB reste faible par rapport aux secteurs tertiaire et secondaire. Une des principales raisons de cette situation est sa forte dépendance aux conditions climatiques et notamment à la pluviométrie. Dans cette recherche nous nous proposons d’étudier l’analyse des effets de la pluviométrie sur le PIB du sous- secteur agricole au Sénégal. L’étude couvre une période de 35 ans allant de 1980 à 2015 et concerne tout le territoire national. Les résultats des tests économétriques par la technique des Moindres Carrés Ordinaires (MCO) montrent que la variation pluviométrique influence les résultats économiques du secteur agricole. L’étude montre qu’à chaque fois que la pluviométrie baisse, les productions et les valeurs économiques du mil et de l’arachide suivent la même tendance. Ainsi une bonne pluviométrie a un effet positif sur la production agricole qui à son tour influence positivement le PIB agricole. ABSTRACTANALYSIS OF THE EFFECTS OF RAINFALL ON AGRICULTURAL GDP IN SENEGALThe agricultural sector in Senegal is dominated by rainfed crops, with groundnuts and millet occupying most of the land. Its contribution to GDP remains low compared to the tertiary and secondary sectors. One of the main reasons for this situation is its strong dependence on climatic conditions and in particular on rainfall. In this research we propose to study the analysis of the effects of rainfall on the GDP of the agricultural sub-sector in Senegal. The study covers a 35-year period from 1980 to 2015 and concerns the entire national territory. The results of econometric tests using the Ordinary Least Squares (OLS) technique show that rainfall variation influences the economic performance of the agricultural sector. The study shows that each time the rainfall drops, the production and economic values of millet and peanuts follow the same trend. Thus, good rainfall has a positive effect on agricultural production which in turn positively influences agricultural GDP

Controlling structural distortion in the geometrically frustrated layered cobaltate YBaCo4O7+{\delta} by Fe substitution and its role on magnetic correlations

Effects of Fe-substitution on the crystal structure and magnetic correlations of the geometrically frustrated antiferromagnets YBaCo4-xFexO7+{\delta} (x = 0, 0.2, 0.4, 0.5, 0.6, and 0.8) have been studied by neutron diffraction, M\"ossbauer spectroscopy, and ac susceptibility. The compounds YBaCo4-xFexO7+{\delta} have a special layered-type crystal structure with an alternating Kagom\'e (6c site) and triangular (2a site) layers along the c axis. Fe3+ ions are found to be substituted at both the crystallographic 2a and 6c sites of Co ions. M\"ossbauer results show a high spin state of Fe3+ ions in a tetrahedral coordination. A reduction in the distortion of the Kagom\'e lattice has been observed with the Fe-substitution. The correlation length of the short-range antiferromagnetic ordering decreases with the Fe-substitution. The sharpness of the magnetic transition also decreases with the Fe-substitution.Comment: 26 pages, 8 figures, 3 table