453 research outputs found

    Documenting museum records of west African Coccinellidae (Coleoptera) in Benin and Senegal

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    Open Access JournalThis work provides a preliminary inventory of West African Coccinellidae. This was based on the West African Coccinellidae (WAC) specimens in the holdings of insect collections at the Laboratoire de Zoologie des Invertébrés Terrestres at the Institut Fondamental d’Afrique Noire Cheikh Anta Diop (IFAN), Senegal and the Biodiversity Center at the International Institute of Tropical Agriculture (IITAB), Benin

    Biotechnology and the African Farmer

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    Research and Development/Tech Change/Emerging Technologies,

    Urban agriculture in Senegal: effect of wastewater on the agronomical performance and hygienic quality of tomato and lettuce

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    The use of wastewater in urban agriculture has gained a lot of interest in Senegal. The aim of this works was to assess the effect of wastewater on the agronomical performance of two vegetable crops and the hygienic threats as compared to tap water. We also compared the effect of irrigation mode and the addition of fertilizers. Results showed that there were no significant differences between the two irrigation modes. Thesturdiness at 2 months had a positive effect on the number of plant (tomato) at the harvest, the yield and fruit average weight. Considering the following parameters studied (overall yield, corrected yield, number of fruit per treatment and fruit average size, there were significant differences between plants (lettuce) treated with tap water and those treated with wastewater. In a chemical point of view, samples from aspersion and draining watering mode treatments were similar in term of their content in heavy metals. On the lettuce, results showed a low presence of worms on crop watered with wastewater. On the other hand, lettuce watered with theaspersion technique contents much more germs of pathogens than those watered in draining mode. As for tomato, there was a total absence of worms and other pathogenic germs in both irrigation modes. This studysuggests that use of wastewater in horticulture with a moderate fertilization and taking into account soil chemistry could be gainful to urban farmers. The study addresses the issue of preliminary studies on the wastewater and soil quality before deciding on the adequate crop to grow

    Self-cleaning on a higher order mode in ytterbium-doped multimode fiber with parabolic profile

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    We experimentally demonstrate polarization-dependent Kerr spatial beam self-cleaning into the LP11 mode of an Ytterbium-doped multimode optical fiber with parabolic gain and refractive index profiles

    La pêche artisanale au Sénégal : qualité de la matière première destinée aux entreprises exportatrices

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    Les conditions d’hygiène de la pêche artisanale au Sénégal ne respectent pas toujours les normes de qualité requises. Ce présent travail se propose d’étudier la qualité de trois espèces de poissons démersaux ; la sole limande (Syacium guineensis), le mérou à points bleus (Cephalopholis taeniops) et le rouget (Pseudupeneus prayensis) débarqués par la pêche artisanale. Ces espèces sont suivies depuis la capture jusqu’à leur acheminement en usine. L’évaluation sensorielle de la fraîcheur du poisson a consisté à tester la qualité par le toucher, l’odorat, la vue et le goût. Le dosage de l’azote basique volatil total (ABVT) a permis de déterminer la teneur totale en azote des bases azotées volatiles résultant de la dégradation des composés azotés du poisson lors de l’altération. La méthode d’analyse microbiologique utilisée est celle qui consiste à incorporer un volume donné de la prise d’essai et de ses dilutions dans un milieu de culture solide. A l’analyse sensorielle, les trois espèces, aux différentes étapes, étaient de très bonne qualité. Les valeurs de la flore mésophile aérobie sur le poisson à la capture sont très faibles contrairement au débarquement et à l’entrée en usine. Au niveau des branchies et de la peau, les résultats montrent une augmentation significative de la flore au débarquement et à l’entrée en usine. Au niveau des viscères, la flore augmente jusqu’au débarquement puis décroît. Les résultats des analyses chimiques ne reflètent pas forcément les risques de dégradation du poisson.Mots-clés : pêche artisanale, poisson, qualité matière première, exportation, Sénégal.Artisanal fisheries in Senegal: Quality of raw materials for exporting companiesHygienic conditions of artisanal fisheries in Senegal do not always respect the required quality standards. This study expects to scrutinize the quality of bottom fish sole (Syacium guineensis), grouper blue spotted (Cephalopholis taeniops), red mullet (Pseudupeneus prayensis) disembarked by artisanal fisheries. These species are followed since the capture until their routing in factory. The sensory evaluation of fish freshness was to test the quality through touch, smell, sight and taste. The determination of total volatile basic nitrogen (ABVT) allowed determining the total nitrogen content of volatile nitrogenous bases resulting from the degradation of nitrogenous compounds in fish spoilage. The used-microbiological-method is the one that consist in incorporating a given volume of the sample and its dilutions in a solid cultural medium. The results of sensory analysis on the three species at different stopovers were very good. The values of the aerobic mesophilic flora on the fish caught are very low compared to the one landed at the entrance to the factory. At the gills and skin, the findings show a significant increase in flora and landed at the entrance to the factory. In the viscera, flora increases and then decreases until the debarkation. The results of sensory and chemical analysis may not reflect the risks of degradation of fish.Keywords : artisanal fisheries, fish, quality, raw materials, exportation, Senegal

    Editorial review: Male circumcision, gender and HIV prevention in sub-Saharan Africa: a (social science) research agenda

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    No Abstract.SAHARA J Vol. 4 (3) 2007: pp. 658-66

    Instability of a Soliton Crystal in a High Power Fiber Laser

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    We investigate experimentally the soliton pattern formation in passively modelocked fiber lasers. Under specific conditions a stable soliton crystal is formed. We demonstrate that the crystal becomes unstable when the pumping power increases resulting in a splitting into crystals of smaller extent
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