27 research outputs found

    Zootechnical study of breeding modes of Somba cattle in Benin

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    The Somba cattle (Bos Taurus brachyceros sp), located in Benin and Togo, has a severe reduction of its livestock in recent decades. The aim of this study was to determine the causes of this phenomenon, in order to propose new approaches of conservation. The study consisted of surveys with targeted farmers and cattle. The results indicate that Somba cattle are not cared for both in terms of food and health, justifying its low performance and high mortality rate. The parameters covered by the study vary from one mode of farming to another. For individual parameters, entrusted farming is more interesting. In more than 80% of the farms of this mode, age at first calving is around 36 months, whereas it is of 42 months in the home farming, and have an inter calving period of 14 months which is also less than 24 months in the second case. Demographic parameters seem more interesting than home farming. Then, the mortality rate is 13.46% in home farming against 16.61% in entrusted farming. Regarding to external factors, health monitoring is lax in both modes. Food is a great concern especially during the dry season. The absorption by zebu was often mentioned as the main cause of the decrease of Somba cattle livestock. The present study shows that high mortality due to an absence of health monitoring is the basis of the sharp decline in the number of Somba cattle. The influence of zebu is currently marginal because 96.22% of cattle at the farm level respondents are Somba breed.Keywords: Parameters, individuals, demographic, livestock, conservation, mortalit

    Making linearizability compositional for partially ordered executions

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    In the interleaving model of concurrency, where events are totally ordered, linearizability is compositional: the composition of two linearizable objects is guaranteed to be linearizable. However, linearizability is not compositional when events are only partially ordered, as in the weak-memory models that describe multicore memory systems. In this paper, we present a generalisation of linearizability for concurrent objects implemented in weak-memory models. We abstract from the details of specific memory models by defining our condition using Lamport’s execution structures. We apply our condition to the C11 memory model, providing a correctness condition for C11 objects. We develop a proof method for verifying objects implemented in C11 and related models. Our method is an adaptation of simulation-based methods, but in contrast to other such methods, it does not require that the implementation totally orders its events. We apply our proof technique and show correctness of the Treiber stack that blocks on empty, annotated with C11 release-acquire synchronisation

    Production des ovins Djallonké en station dans la zone guinéenne au Bénin : 1. Performances de reproduction et influence des facteurs non génétiques

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    peer reviewedDe 1994 Ă  2002, les donnĂ©es relatives aux performances de reproduction ont Ă©tĂ© recueillies sur les ovins DjallonkĂ©. Ces donnĂ©es provenaient de la Ferme de la FacultĂ© des Sciences Agronomiques (UniversitĂ© d’Abomey Calavi). Le modĂšle linĂ©aire gĂ©nĂ©ral (GLM) et le test t de Student ont Ă©tĂ© utilisĂ©s pour, analyser les donnĂ©es, identifier et quantifier les facteurs non-gĂ©nĂ©tiques affectant l’ñge au premier agnelage, l’intervalle entre agnelages et la prolificitĂ©. Les rĂ©sultats ont montrĂ© : Ăąge au premier agnelage, 609,64jours±110,26 jours ; intervalle entre agnelages, 243,01jours±68,19jours ; prolificitĂ©, 1,28±0,45 ; taux annuel de reproduction 1,92% ; taux de stĂ©rilitĂ© temporaire, 5,79%. Les effets de la saison d’agnelage, de l’annĂ©e d’agnelage et de l’interaction annĂ©e*saison ont Ă©tĂ© trĂšs importants (p<0,01) sur l’ñge au premier agnelage et sur l’intervalle entre agnelages. Pour le caractĂšre prolificitĂ©, les mĂȘmes facteurs n’ont pas d’effets significatifs (p>0,05) Production of Djallonke sheep at an experimental station in the guinean zone of Benin.Production of Djallonke sheep at an experimental station in the guinean zone of Benin. Reproduction performance and influence of non-genetic factors From 1994 to 2002, data from Djallonke sheep were collected for reproduction performance. The data were obtained from the farm of the Faculty of Agronomic Sciences (University of Abomey Calavi). Data analysed by GLM procedure and Student’s t-test, were used to identify and quantify non-genetics factors affecting the age at first lambing, intervals between lambing and prolificacy. Results indicated: age at first lambing, 609.64days±110.26 days; intervals between lambing, 243.01days±68.19days; prolificity, 1.28±0.45; annual reproduction rate, 1.92%; temporary sterility rate, 5.79%. Lambing season, lambing year and the year*season interaction affected significantly (p0.05) for prolificacy

    Multifaceted impacts of sustainable land management in drylands: A review

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    Biophysical restoration or rehabilitation measures of land have demonstrated to be effective in many scientific projects and small-scale environmental experiments. However circumstances such as poverty, weak policies, or inefficient scientific knowledge transmission can hinder the effective upscaling of land restoration and the long term maintenance of proven sustainable use of soil and water. This may be especially worrisome in lands with harsh environmental conditions. This review covers recent efforts in landscape restoration and rehabilitation with a functional perspective aiming to simultaneously achieve ecosystem sustainability, economic efficiency, and social wellbeing. Water management and rehabilitation of ecosystem services in croplands, rangelands, forests, and coastlands are reviewed. The joint analysis of such diverse ecosystems provides a wide perspective to determine: (i) multifaceted impacts on biophysical and socio-economic factors; and (ii) elements influencing effective upscaling of sustainable land management practices. One conclusion can be highlighted: voluntary adoption is based on different pillars, i.e. external material and economic support, and spread of success information at the local scale to demonstrate the multidimensional benefits of sustainable land management. For the successful upscaling of land management, more attention must be paid to the social system from the first involvement stage, up to the long term maintenance. © 2016 by the authors
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