Caractérisation agronomique, économique et biophysique du continuum bas fond : cas des complexes sahéliens et soudano -sahéliens du sine-saloum au Senegal

La productivité rizicole dans les complexes de bas fonds pluviaux notamment ceux des régions sahéliennes et soudanosahéliennes dépend de la maîtrise de l\'eau. A l\'Ouest du Sénégal, dans la région du Sine Saloum, la salinité des bas fonds résulte du contact avec un bras de mer. Pour lever les effets néfastes de la salinité et autoriser la maîtrise de l\'eau, une digue a été édifiée dans les bas fonds du village de Ndour Ndour. Pour rentabiliser cet ouvrage, des activités agricoles ont été initiées sous l\'impulsion des partenaires au développement. Le rôle de la recherche dans ce partenariat a consisté entre autres activités à la caractérisation agronomique, économique et biophysique du continuum bas fond. La reprise de la riziculture de bas fond s\'inscrit dans cette nouvelle dynamique avec une amélioration de la productivité et l\'adhésion des hommes à cette activité jusque-là réservée aux femmes. Il faut retenir que les sols sont essentiellement sableux en surface et que la retenue d\'eau douce (digue ) élimine le sel des sols qui deviennent propices pour l\'agriculture.Rice productivity in rainfall lowlands complexes such as sahelian and sudanese sahelian regions, depends on water control. In western Senegal Sine Saloum Region, lowlands salinity is due to sea contact. To reduce negative salinity effects and maintain good water control, a dam was built in Ndour Ndour village. To optimize input of this dam, agricultural activities were conducted with extension parteners. The main role of scientists in this partership is the agronomic, economic and biophysical characterization of lowlands continuum. Lowlands rice cultivation in this new context is characterized by significant productivity improvement and male\'s effective involvement in this activity, so far conducted by women. The study showed that most soils are sandy; in addition and the dam allows to maintain river water in place and to eliminate salts, making soils suitable for agriculture. Keywords: caractérisation, bas fond, riziculture, productivité, salinisation, digue, collaboration/characterization, owland, rice culture, productivity, salinisation, dam, collaboration.Sciences & Nature Vol. 4 (1) 2007: pp. 1-1

Hidden Symmetry of the Differential Calculus on the Quantum Matrix Space

A standard bicovariant differential calculus on a quantum matrix space ${\tt Mat}(m,n)_q$ is considered. The principal result of this work is in observing that the $U_q\frak{s}(\frak{gl}_m\times \frak{gl}_n))_q$ is in fact a $U_q\frak{sl}(m+n)$-module differential algebra.Comment: 5 page

Valeur de la méthode d'immunofluorescence indirecte dans le diagnostic des trypanosomiases bovines et leur étude épizootologique

Des épreuves d'immunofluorescence indirecte, pratiquées dans les trypanosomiases bovines, il ressort que cette méthode, quoique très sensible et utile dans les études d'épizootologie et les recherches sur les anticorps, a cependant un intérêt plus limité en matière de diagnostic du fait de l'impossibilité de déceler des infections précoces, des incertitudes quant aux espèces de trypanosomes en cause et aussi parce que la présence d'anticorps ne traduit pas nécessairement une infection présent

Histomorphology and Biochemical Effects of Sida acuta leaf Extract on the Kidney of Wistar Rats

This study assessed the effect of ethanolic extract of Sida acuta leaf on the micro-anatomy of the kidney of Wistar rats. Thirty adult Wistar rats were separated into 3 groups A, B and C (n=10 per group). The Wistar rats were subjected to different doses of ethanolic extract of Sida acuta in order to evaluate the possible micro-anatomy/morphological changes in the kidney following the administration of the extract. The rats in group A were regarded as control and they received only distilled water throughout the period. The rats in group B and C were the treated groups and received ethanolic extract of Sida acuta leaves daily at doses 100 and 200mg/kgbw orally for 14 days respectively. The animals were sacrificed on the 15th day by cervical dislocation and the kidney excised. Fixed in 10% formal saline and processed for light microscopy using H&E staining methods. Finding from rats’ weight that there was a significant (P<0.05) decrease in body weight of the treated rats compared with the control group. The histological study revealed compressed renal corpuscle, increased bowman’s space and constricted collecting tubule which may adversely affect renal functions. Key words: Sida acuta, Kidney, histomorphology, biochemica

The Anxiolytic Effects of Smokeless Tobacco in Mice

This study assessed the effect of smokeless tobacco leaf on anxiety in mice. Twenty male albino mice, aged 60-120 days were separated into 2 groups of ten each. Animals in the test group were fed on 0.1g of tobacco mixed with 10g of chow everyday for 14 days. While animals in the control group were given only 10g of chow for the same duration. The mice were then allowed 5 minutes each to explore the excavated plus maze and the light/dark transition box and behaviours were scored. Results in the elevated plus maze revealed that the duration in the open arms was significantly different (p<0.05) between the two groups with the test group (49.6± 11.9 sec/5 mins) being lower than the control group (89.1± 22.1 sec/5min). The frequency of stretch attend postures was significantly lowered (p<0.05) in the test group (8.8±0.6) compared to the control (11.5±1.8). There was no significant difference in the other parameters in the elevated plus maze. The frequency of line crosses in the light box was significantly higher (p<0.01) for the test group (74.3±9.8) than the control (47.4±63). The frequency of stretch attends posture and rearing in the dark box was significantly higher (p<0.05) in the test group then the control group (180.5±18.9). These results suggest that tobacco may have decreased anxiety in the test group. Keyword: Anxiety, postures, elevated plus maze

Filling a blank on the map: 60 years of fisheries in Equatorial Guinea

Despite a scarcity of pertinent information, it has been possible to reconstruct time series of marine fisheries catches for Equatorial Guinea from 1950 to 2010 using per capita fish consumption and population numbers for small-scale fisheries, catch rates and number of vessels for industrial fisheries and discard rates to estimate the discarded bycatch. Small-scale fisheries, industrial large-scale fisheries, domestic and legal and illegal foreign fisheries and their discards are all included. Total catches were estimated at 2.7 million tonnes over the time period considered, of which 653 000 t were caught domestically compared to 187 000 t reported by FAO. This shows that fisheries have more importance for Equatorial Guinea's food security than the official data suggest. In contrast to what is suggested by official figures, fisheries were shown to be strongly impacted by civil and political unrest; notably, they declined overall because of civil and political conflicts, socio-demographic dynamics, and a growing role of the newly discovered oil resources, which directly and indirectly threaten the food security of the people of Equatorial Guinea

Diffusion des conseils agricoles au cours de la campagne 2022 au Sénégal

L'objectif d'AICCRA est d'accroître l'accès des prestataires de services de recherche et de vulgarisation agricoles en Afrique aux connaissances, aux technologies et aux outils de prise de décision pertinents pour améliorer la résilience des systèmes agricoles et alimentaires face au changement climatique. Ce projet vise à mettre en œuvre la composante sous régionale d'AICCRA en Afrique de l’Ouest en mettant en place des partenariats multi-acteurs de réseaux et de centres scientifiques et éducatifs existants afin d'atteindre des résultats qui ne peuvent pas être atteints facilement, voire pas du tout, en s'engageant avec des partenaires individuels au niveau national. Plus précisément, ce projet renforcera la capacité des institutions publiques régionales (par exemple, CERAAS/ISRA, ANACIM, ANCAR, etc.) et des entreprises privées (par exemple, les fournisseurs d'intrants, les entreprises de TIC, les médias) à développer des modèles d’affaire pour les services climatiques et pour la connaissance des AIC, des approches et des outils pour soutenir une adoption efficace inter-régionale et sud sud dans diverses chaînes de valeur. Dans le cadre de la mise en œuvre du projet AICCRA, l’ institut international de recherche sur l’elevage (ILRI) collabore avec l’entreprise Jokalante pour assurer la diffusion des informations climatiques et conseils agricoles en voix et en deux (2) langues locales auprès des producteurs. Ainsi durant la campagne agricole de Juillet a Decembre des conseils agricométéorologiques ont été diffusés auprès des producteurs à l’issue desquels une phase d’évaluation est jugée nécessaire pour recueillir la perception des bénéficiaires sur le service reçu mais aussi analyser les effets de ces services sur leurs activités agricoles. Les résultats de cette évaluation ainsi que les différentes activités de cette campagne font l’objet de ce présent document

Room-temperature ferromagnetism in graphite driven by 2D networks of point defects

Ferromagnetism in carbon-based materials is appealing for both applications and fundamental science purposes because carbon is a light and bio-compatible material that contains only s and p electrons in contrast to traditional ferromagnets based on 3d or 4f electrons. Here we demonstrate direct evidence for ferromagnetic order locally at defect structures in highly oriented pyrolytic graphite (HOPG) with magnetic force microscopy and in bulk magnetization measurements at room temperature. Magnetic impurities have been excluded as the origin of the magnetic signal after careful analysis supporting an intrinsic magnetic behavior of carbon. The observed ferromagnetism has been attributed to originate from unpaired electron spins localized at grain boundaries of HOPG. Grain boundaries form two-dimensional arrays of point defects, where their spacing depends on the mutual orientation of two grains. Depending on the distance between these point defects, scanning tunneling spectroscopy of grain boundaries showed two intense split localized states for small distances between defects (< 4 nm) and one localized state at the Fermi level for large distances between defects (> 4 nm).Comment: 19 pages, 5 figure