314 research outputs found
Sampling constants in generalized Fock spaces
We discuss sampling constants for dominating sets in generalized Fock spaces.Comment: arXiv admin note: text overlap with arXiv:2004.0503
Modeles mathematiques du mode temps monopartage des systemes informatiques dâentreprise
Principles of the models development of optimum management processes of access in the computers networks of the corporative information systems are reviewed and the results of the adequacy estimation of these models are presented.Dans le travail nous considérons les principes de conception
des modĂšles de processus optimaux de contrĂŽle dâaccĂšs dans
les réseaux informatiques des systÚmes informatiques
dâentreprise et prĂ©sentons les rĂ©sultats dâĂ©valuation de
lâadĂ©quation de ces modĂšles
Estimating the burden of malaria in Senegal : Bayesian zero-inflated binomial geostatistical modeling of the MIS 2008 data
The Research Center for Human Development in Dakar (CRDH) with the technical assistance of ICF Macro and the National Malaria Control Programme (NMCP) conducted in 2008/2009 the Senegal Malaria Indicator Survey (SMIS), the first nationally representative household survey collecting parasitological data and malaria-related indicators. In this paper, we present spatially explicit parasitaemia risk estimates and number of infected children below 5 years. Geostatistical Zero-Inflated Binomial models (ZIB) were developed to take into account the large number of zero-prevalence survey locations (70%) in the data. Bayesian variable selection methods were incorporated within a geostatistical framework in order to choose the best set of environmental and climatic covariates associated with the parasitaemia risk. Model validation confirmed that the ZIB model had a better predictive ability than the standard Binomial analogue. Markov chain Monte Carlo (MCMC) methods were used for inference. Several insecticide treated nets (ITN) coverage indicators were calculated to assess the effectiveness of interventions. After adjusting for climatic and socio-economic factors, the presence of at least one ITN per every two household members and living in urban areas reduced the odds of parasitaemia by 86% and 81% respectively. Posterior estimates of the ORs related to the wealth index show a decreasing trend with the quintiles. Infection odds appear to be increasing with age. The population-adjusted prevalence ranges from 0.12% in Thille-Boubacar to 13.1% in Dabo. Tambacounda has the highest population-adjusted predicted prevalence (8.08%) whereas the region with the highest estimated number of infected children under the age of 5 years is Kolda (13940). The contemporary map and estimates of malaria burden identify the priority areas for future control interventions and provide baseline information for monitoring and evaluation. Zero-Inflated formulations are more appropriate in modeling sparse geostatistical survey data, expected to arise more frequently as malaria research is focused on eliminatio
Etablissement dâun protocole efficace de germination des graines du thĂ© de savane (Lippia multiflora Mold., Verbenaceae)
Lippia multiflora Mold. est une plante aromatique qui croĂźt spontanĂ©ment dans les zones de savanes de lâAfrique subtropicale. Elle est utilisĂ©e dans les traitements de lâhypertension artĂ©rielle, du paludisme et autres affections gastriques. Lâinsuffisance de matĂ©riels de plantation, due au faible taux de germination des graines, limite lâextension de la culture. La prĂ©sente Ă©tude vise Ă dĂ©finir les conditions optimales pour la production de plants Ă partir de graines. Les graines ont ainsi Ă©tĂ© traitĂ©es avec diffĂ©rents agents chimiques avant le semis dans des boĂźtes de PĂ©tri, sur du papier filtre ou sur le milieu de base de Murashige et Skoog (MS). Sur le papier filtre, lâimbibition dans lâeau distillĂ©e des graines, pendant 24 heures, a donnĂ© le meilleur taux de germination (59,01 %). La stĂ©rilisation des graines dans lâacide sulfurique 96 % durant 1 minute, suivie dâun trempage pendant 20 minutes dans lâhypochlorite de sodium (3,6 % de chlore actif) a favorisĂ© un faible taux de contamination (3,38 %) et un taux Ă©levĂ© de germination (90,33 %) sur le milieu MS.Mots clĂ©s : Lippia multiflora, germination, graine, stĂ©rilisation
Induction et prolifĂ©ration de cals Ă partir de lâaxe embryonnaire du Voandzou [Vigna subterranea (L.) Verdc. Fabaceae] : effet de la segmentation de lâexplant, des phytohormones, de la source de carbone et du gĂ©notype
Le Voandzou [Vigna subterranea, (L.) Verdc.], occupe une place importante dans les stratĂ©gies Ă©laborĂ©es pour assurer la sĂ©curitĂ© alimentaire en Afrique subsaharienne. Le dĂ©veloppement de systĂšmes de rĂ©gĂ©nĂ©ration in vitro de plantes, prĂ©alable au transfert de gĂšnes nĂ©cessite lâĂ©tablissement de conditions optimales de la callogenĂšse. Au cours du prĂ©sent travail, lâĂ©tude des facteurs influençant lâinduction et la prolifĂ©ration des cals chez le Voandzou a Ă©tĂ© rĂ©alisĂ©e. Lâaxe embryonnaire issu de graines matures a Ă©tĂ©Â placĂ© sur le milieu de base de Murashige et Skoog (1962) additionnĂ© avec les vitamines B5 et supplĂ©mentĂ©Â avec diffĂ©rentes concentrations et combinaisons de phytohormones. AprĂšs quatre semaines de culture, les rĂ©sultats ont montrĂ© que lâinduction et la prolifĂ©ration de cals ont Ă©tĂ© favorisĂ©es avec le 2,4-D (0,5 mg/l). La partie basale de lâaxe embryonnaire a Ă©tĂ© la zone la plus favorable Ă la callogenĂšse. La meilleure source de carbone a Ă©tĂ© le saccharose Ă la concentration optimale de 84 mM. Les meilleurs taux dâinduction (100 %) et de prolifĂ©ration de cals (3) ont Ă©tĂ© exprimĂ©s avec les Ă©cotypes Ci2, Ci3, Ci4, Ci5, Ci6, Ci7, Ci10 et Ci21.Mots-clĂ©s : voandzou, axe embryonnaire, callogenĂšse, phytohormones.Callus induction and proliferation from embryonic axis in Bambara groundnut [Vigna subterranea (L.) Verdc. Fabaceae]: effect of explants section, plant growth regulators, carbon source and genotypeBambara groundnut [Vigna subterranea (L.) Verdc. ] contributes to food security in sub-Saharan Africa. Development of efficient systems of in vitro plant regeneration a prerequisite to gene transfer requires establishment of optimal conditions for callus formation. In this work, factors influencing callus induction and proliferation in Bambara have been studied. Embryonic axis derived mature seeds were placed on Murashige and Skoog (1962) medium supplemented with vitamins B5 (MSB5), including different concentrations and combinations of plant growth regulators. After four weeks of culture, results showed that 2,4-D (0.5 mg/L) exhibited the best frequency and proliferation index of callus. Basal part of embryonic axis was the explants of choice for callus induction and proliferation. Sucrose at optimum concentration of 84 mM was favorable to the process of callus formation. Highest callus induction frequency (100 %) and proliferation index (3) were expressed by ecotypes Ci2, Ci3, Ci4, Ci5, Ci6, Ci7, Ci10 and Ci21.Keywords : bambara groundnut, embryonic axis, callogenesis, plant growth regulators
Characterization and evaluation of accessions of Bambara groundnut (Vigna subterranea (L.) Verdcourt) from Burkina Faso
Three hundred and ten (310) Bambara groundnut accessions mainly from the Northern semi arid zone of Burkina Faso were assessed for phenotypic variability of agronomic and morphological traits. Mixture of seed types in a given accession is common in Northern area of Burkina Faso. Two to twelve types of seeds compose the majority of
accessions collected (82%) and only 18% of accessions are homogeneous. Characters like canopy spread, number of pods per plant, number of seeds per pod, seed length, seed width and weight of 100 seeds are positively correlated to yield per plant. A negative correlation was revealed between days to 50% flowering and yield per plant indicating
that plants which take more time on vegetative stage have less yield in semi-arid conditions of production. Accessions from Burkina assessed for agronomic and morphological characteristics in this study are less variable than 1384 accessions assessed by IITA in 1985 and 1986. This result can be explained by the restricted origin of accessions
from Burkina Faso.La variabilité phénotypique des traits agronomiques et morphologiques de 310 accessions de pois Bambara collectées principalement dans la zone semi aride nord du Burkina Faso a été évaluée. Le mélange de différents
types de semences dans les accessions est une pratique répandue dans le Nord du Burkina Faso. Deux à douze types de semence composent la majorité des accessions (82%) et seulement 18% des accessions sont homogÚnes. Les caractÚres tels que la largeur du feuillage, le nombre de gousses par plante, le nombre de graines par gousse,
la longueur et largeur des graines et le poids de 100 graines ont une corrélation positive avec le rendement en graine par plante. Une corrélation négative a été mise en évidence entre la date de 50% floraison et le rendement par plante montrant que les plantes qui prennent plus de temps pour leur phase végétative produisent moins dans les conditions
de production semi arides. Les accessions du Burkina évaluées pour leurs caractéristiques agronomiques et morphologiques sont moins variables que les 1384 accessions évaluées par l\'IITA en 1985 et 1986. Ce résultat peut s\'expliquer l\'origine restreinte des accessions originaires du Burkina. Keywords: Agronomic evaluation, Bambara groundnut, Mixture of seeds, Phenotypic variability, Vigna subterranea.Sciences & Nature Vol. 5 (2) 2008: pp. 191-19
Antécédents culturaux et identification de quelques pratiques paysannes en replantation cacaoyÚre en CÎte d'Ivoire
La CĂŽte dâIvoire est le premier producteur mondial de cacao, avec plus de 1700 000 tonnes. Cette performance a Ă©tĂ© atteinte, principalement, par lâaccroissement des superficies cultivĂ©es aux dĂ©pends de la forĂȘt. LâenquĂȘte a concernĂ© les parcelles de cacaoyers de moins de 5 ans (0-5 ans) et chaque producteur a Ă©tĂ© enquĂȘtĂ© individuellement, chacun sur sa parcelle, afin de confronter les rĂ©ponses aux observations de terrain. Les rĂ©sultats des enquĂȘtes effectuĂ©es, entre 2002 et 2003, par le projet PIC-CACAO, montrent que trois types dâantĂ©cĂ©dents culturaux sont actuellement utilisĂ©s pour la culture du cacaoyer en CĂŽte dâIvoire. Il sâagit des vieilles cacaoyĂšres, des vieilles cafĂ©iĂšres et des jachĂšres, moins favorables Ă la culture du cacaoyer. Face aux contraintes rencontrĂ©es au cours du renouvellement du verger cacaoyer sur ces antĂ©cĂ©dents, les producteurs ont, soit adoptĂ© des techniques proposĂ©es par la recherche, soit adaptĂ© certaines de leurs pratiques endogĂšnes aux nouvelles conditions écologiques et naturelles du milieu. Les adoptions ont concernĂ©s lâutilisation de matĂ©riel vĂ©gĂ©tal amĂ©liorĂ©, issu des pĂ©piniĂšres, sur les jachĂšres. Quant aux adaptations, elles se sont traduites par la pratique de fortes densitĂ©s de plantation de jeunes cacaoyers et par la densification de lâombrage.Mots clĂ©s: Cacaoyer, antĂ©cĂ©dents culturaux, adoptions, adaptations, CĂŽte dâIvoireEnglish Title: Cropping history and identification of some farmer pratices in cocoa replanting in CĂŽte dâIvoireEnglish AbstractCĂŽte dâIvoire is the first producer of cocoa worldwide with more than 1700 000 tons. This performance was reached, mainly, by the increase of acreages at the expense of the forest. The investigation concerned the cocoa plots under 5 years (0-5 years) and each producer was investigated individually, each on his plot in order to compare his responses with field observations. The results of the investigations carried out, between 2002 and 2003, by PIC-cacao project, show that three types of antecedents are currently used for the culture of the cocoa-tree. They are the old cocoa plantations, the old coffee plantations and the fallow, less favourable of the cultivation of cocoa. Faced with the constraints during the renewal of the cocoaorchard on these antecedents, producers adopted techniques proposed by research or adapted some endogenous practices to the new ecological and natural conditions of the environment. The adoptions related to the use of vegetable material improved and nurseries on the fallow. As for the adaptations, they resulted in the use of high densities of plantation of young cocoa-trees and to the thickening of the shade.Keywords: Cocoa-orchard (Theobroma cacao L.), farming antecedents, adoptions, adaptations, CĂŽte dâIvoir
Species occurrence of cetaceans in Guinea, including humpback whales with southern hemisphere seasonality
An initial inventory of the dolphins and whales occurring in Guinea's coastal waters is documented primarily from specimens and photographic evidence obtained from strandings and by-catches. Seven species are fully validated, four odontocetes, Tursiops truncatus, Sousa teuszii, Stenella frontalis, Kogia breviceps and three balaenopterid whales: Balaenoptera brydei, Balaenoptera acutorostrata and Megaptera novaeangliae. Another three reported species (Globicephala macrorhynchus, Steno bredanensis and Delphinus delphis) are insufficiently supported but thought to be valid. Small cetaceans landed as by-catch and a stranded whale were used for human consumption, but no evidence of substantial takes, directed or by-catch, was found. However, concern is raised about even minimal takes of the vulnerable Atlantic humpback dolphin. The seasonal presence of three confirmed humpback whales, two strandings (July and September) and a sighting (October), is synchronous with the species' southern hemisphere wintering/breeding season in low latitudes. We hypothesize that these whales may comprise the north-westernmost range of the population that breeds/overwinters in coastal waters of the Bight of Benin, northern Gulf of Guinea
Past, Present and Future Perspectives on Groundnut Breeding in Burkina Faso
Groundnut (Arachis hypogaea L.) is a major food and cash crop in Burkina Faso. Due to
the growing demand for raw oilseeds, there is an increasing interest in groundnut production from
traditional rain-fed areas to irrigated environments. However, despite implementation of many
initiatives in the past to increase groundnut productivity and production, the groundnut industry still
struggles to prosper due to the fact of several constraints including minimal development research
and fluctuating markets. Yield penalty due to the presence of drought and biotic stresses continue
to be a major drawback for groundnut production. This review traces progress in the groundnut
breeding that started in Burkina Faso before the countryâs political independence in 1960 through to
present times. Up to the 1980s, groundnut improvement was led by international research institutions
such as IRHO (Institute of Oils and Oleaginous Research) and ICRISAT (International Crops Research
Institute for the Semi-Arid Tropics). However, international breeding initiatives were not suïżœcient to
establish a robust domestic groundnut breeding programme. This review also provides essential
information about opportunities and challenges for groundnut research in Burkina Faso, emphasising
the need for institutional attention to genetic improvement of the crop
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