Performance environnementale et economique dans la production de la grande morelle (Solanum macrocarpon) au Sud du Benin : Une evaluation des efficacites technique, allocative, economique

L’objectif de cette étude est d’analyser les efficacités technique, allocative et économique dans la production de la grande morelle. Pour cela, une  étude descriptive et analytique a été réalisée sur un échantillon de 126 maraîchers des sites de production de Houéyiho, de Sèmè-Kpodji et de  Ouidah au sud du Bénin. Les efficacités technique et économique ont été estimées respectivement à l’aide des modèles frontières stochastiques translogarithmique et fonction de coût dual avec la spécification Cobb-Douglas. Le modèle de régression tobit a été utilisé afin d’identifier les facteurs déterminants les efficacités des producteurs. Les résultats obtenus montrent que les facteurs main-d’oeuvre et engrais chimique sont sur-utilisés, ce qui entraîne des inefficacités dans la production. Les efficacités technique, allocative et économique sont respectivement en moyenne de 0,689 ; 0,882 et de 0,607. L’âge du producteur, la superficie emblavée, la contribution de la grande morelle dans le revenu, le niveau d’instruction et la formation technique sont les principaux déterminants des efficacités technique, allocative et économique des producteurs de la grande morelle. Sur la base des résultats obtenus, il importe d’améliorer l’efficacité des producteurs et augmenter ainsi leur profit par la recherche de moyens de lutte efficace et le renforcement de l’encadrement technique des producteurs. Mots clés : efficacités, frontières stochastiques, fonctions translog, fonction Cobb-Douglas, Solanum macrocarpon. English title: Environmental and economic performance in the production of the great nightshade (<i>Solanum Macrocarpon</i>) in southern Benin: An assessment of technical, allocative and economic efficiencies The objective of this study is to analyse the technical, allocative and economic efficiencies in the production of Solanum macrocarpon in Southern-Benin. For this purpose, a descriptive and analytical study was conducted among 126 Solanum macrocarpon growers in Cotonou, Sèmè-kpodji and Ouidah. The technical and economic efficiencies were estimated respectively using translogarithmic stochastic frontier models and dual cost function with the Cobb-Douglas specification. The Tobit regression model was used to identify the determinants of producers efficiencies. The results show that labor and chemical fertilizers are overused, leading to inefficiencies in production. The averages of technical, allocative and economic efficiencies are 0.689; 0.882 and 0.607 respectively. The age of the producer, the surface grown, the contribution of solanum in the income, the educational level and the training in farming are the principal determinants of the technical, allocative and economic efficiencies of the solanum’s producers. On the basis of result obtained, it is important to improve the efficiency of the producers and thus to increase their profit by the search for effective means of pest control and the reinforcement of producer’s technical framing. Key words: efficiency, stochastic frontier analysis, translog function, Cobb-Douglas function, Solanum macrocarpon

Plasmodium falciparum: linkage disequilibrium between loci in chromosomes 7 and 5 and chloroquine selective pressure in Northern Nigeria.

In view of the recent discovery (Molecular Cell 6, 861-871) of a (Lys76Thr) codon change in gene pfcrt on chromosome 7 which determines in vitro chloroquine resistance in Plasmodium falciparum, we have re-examined samples taken before treatment in our study in Zaria, Northern Nigeria (Parasitology, 119, 343-348). Drug resistance was present in 5/5 cases where the pfcrt 76Thr codon change was seen (100% positive predictive value). Drug sensitivity was found in 26/28 cases where the change was absent (93% negative predictive value). Allele pfcrt 76Thr showed strong linkage disequilibrium with pfmdr1 Tyr86 on chromosome 5, more complete than that between pfcrt and cg2 alleles situated between recombination cross-over points on chromosome 7. Physical linkage of cg2 with pfcrt may account for linkage disequilibrium between their alleles but in the case of genes pfmdr1 and pfcrt, on different chromosomes, it is likely that this is maintained epistatically through the selective pressure of chloroquine

Development of a high temperature material model for grade s275jr steel

The paper presents test results for the mechanical and creep properties of the European steel grade S275JR at high temperatures. The objective of the research was to obtain a reliable estimate of creep strain development in the temperature range 400–600 °C, and to identify the critical thermo-mechanical parameters which activate the creep mechanism. Tests of mechanical properties at temperature levels up to 600 °C have shown good agreement with the reduction factors for yield strength and modulus of elasticity given in Eurocode 3 and other comparable studies. A critical temperature for creep development of approximately 400 °C was identified in the tests. The creep tests conducted have also shown that the creep strain rate starts to develop significantly at temperatures around 500 °C when coupons are exposed to a mid-range stress level equal to 60% of the stress at 0.2% strain. The temperature level of 600 °C is identified as the upper-bound temperature for creep development, since creep develops very rapidly, even at very low stress levels. Finally, the paper presents an analytical creep model suitable for implementation in Finite Element-based numerical models

10.34: Creep properties of grade S275JR steel at high temperature

The paper describes an ongoing research project which aims to determine the creep properties of European steel Grade 275JR. The purpose of the research is to develop a reliable temperature‐, stress‐ and time‐dependent creep model for this alloy, since there is very little information available in the scientific community regarding its creep properties. The research within the project is focused on a series of stationary creep tests, which will be used to obtain time‐dependent creep strains in the temperature range 400–600°C. The stress range for which the creep evolution is studied in this project is between 25% and 90% of the value of the stress at 0.2% strain at any particular temperature level. Comparisons between the creep output for the alloy analysed and existing creep data are presented in the paper

The impact of the expansion of urban vegetable farming on malaria transmission in major cities of Benin

BACKGROUND: Urban agricultural practices are expanding in several cities of the Republic of Benin. This study aims to assess the impact of such practices on transmission of the malaria parasite in major cities of Benin. METHOD: A cross sectional entomological study was carried out from January to December 2009 in two vegetable farming sites in southern Benin (Houeyiho and Acron) and one in the northern area (Azèrèkè). The study was based on sampling of mosquitoes by Human Landing Catches (HLC) in households close to the vegetable farms and in others located far from the farms. RESULTS: During the year of study, 71,678 female mosquitoes were caught by HLC of which 25% (17,920/71,678) were Anopheles species. In the areas surveyed, the main malaria parasite, Plasmodium falciparum was transmitted in the south by Anopheles gambiae s.s. Transmission was high during the two rainy seasons (April to July and October to November) but declined in the two dry seasons (December to March and August to September). In the north, transmission occurred from June to October during the rainy season and was vehicled by two members of the An. gambiae complex: Anopheles gambiae s.s. (98%) and Anopheles arabiensis (2%).At Houeyiho, Acron and Azèrèkè, the Entomological Inoculation Rates (EIRs) and the Human Biting Rates (HBRs) were significantly higher during the dry season in Households Close to Vegetable Farms (HCVF) than in those located far from the vegetable areas (HFVF) (p 0.05).The knock-down resistance (kdr) mutation was the main resistance mechanism detected at high frequency (0.86 to 0.91) in An. gambiae s.l. at all sites. The ace-1R mutation was also found but at a very low frequency (< 0.1). CONCLUSION: These findings showed that communities living close to vegetable farms are permanently exposed to malaria throughout the year, whereas the risk in those living far from such agricultural practices is limited and only critical during the rainy seasons. Measures must be taken by African governments to create awareness among farmers and ultimately decentralize farming activities from urban to rural areas where human-vector contact is limited

PLoS Med

Background In 2014, the government of Togo implemented a pilot unconditional cash transfer (UCT) program in rural villages that aimed at improving children’s nutrition, health, and protection. It combined monthly UCTs (approximately US$8.40 /month) with a package of community activities (including behavior change communication [BCC] sessions, home visits, and integrated community case management of childhood illnesses and acute malnutrition [ICCM-Nut]) delivered to mother–child pairs during the first “1,000 days” of life. We primarily investigated program impact at population level on children’s height-for-age z-scores (HAZs) and secondarily on stunting (HAZ < −2) and intermediary outcomes including household’s food insecurity, mother–child pairs’ diet and health, delivery in a health facility and low birth weight (LBW), women’s knowledge, and physical intimate partner violence (IPV). Methods and findings We implemented a parallel-cluster–randomized controlled trial, in which 162 villages were randomized into either an intervention arm (UCTs + package of community activities, n = 82) or a control arm (package of community activities only, n = 80). Two different representative samples of children aged 6–29 months and their mothers were surveyed in each arm, one before the intervention in 2014 (control: n = 1,301, intervention: n = 1,357), the other 2 years afterwards in 2016 (control: n = 996, intervention: n = 1,035). Difference-in-differences (DD) estimates of impact were calculated, adjusting for clustering. Children’s average age was 17.4 (± 0.24 SE) months in the control arm and 17.6 (± 0.19 SE) months in the intervention arm at baseline. UCTs had a protective effect on HAZ (DD = +0.25 z-scores, 95% confidence interval [CI]: 0.01–0.50, p = 0.039), which deteriorated in the control arm while remaining stable in the intervention arm, but had no impact on stunting (DD = −6.2 percentage points [pp], relative odds ratio [ROR]: 0.74, 95% CI: 0.51–1.06, p = 0.097). UCTs positively impacted both mothers’ and children’s (18–23 months) consumption of animal source foods (ASFs) (respectively, DD = +4.5 pp, ROR: 2.24, 95% CI: 1.09–4.61, p = 0.029 and DD = +9.1 pp, ROR: 2.65, 95% CI: 1.01–6.98, p = 0.048) and household food insecurity (DD = −10.7 pp, ROR: 0.63, 95% CI: 0.43–0.91, p = 0.016). UCTs did not impact on reported child morbidity 2 week’s prior to report (DD = −3.5 pp, ROR: 0.80, 95% CI: 0.56–1.14, p = 0.214) but reduced the financial barrier to seeking healthcare for sick children (DD = −26.4 pp, ROR: 0.23, 95% CI: 0.08–0.66, p = 0.006). Women who received cash had higher odds of delivering in a health facility (DD = +10.6 pp, ROR: 1.53, 95% CI: 1.10–2.13, p = 0.012) and lower odds of giving birth to babies with birth weights (BWs) <2,500 g (DD = −11.8, ROR: 0.29, 95% CI: 0.10–0.82, p = 0.020). Positive effects were also found on women’s knowledge (DD = +14.8, ROR: 1.86, 95% CI: 1.32–2.62, p < 0.001) and physical IPV (DD = −7.9 pp, ROR: 0.60, 95% CI: 0.36–0.99, p = 0.048). Study limitations included the short evaluation period (24 months) and the low coverage of UCTs, which might have reduced the program’s impact. Conclusions UCTs targeting the first “1,000 days” had a protective effect on child’s linear growth in rural areas of Togo. Their simultaneous positive effects on various immediate, underlying, and basic causes of malnutrition certainly contributed to this ultimate impact. The positive impacts observed on pregnancy- and birth-related outcomes call for further attention to the conception period in nutrition-sensitive programs

A Landscape and Climate Data Logistic Model of Tsetse Distribution in Kenya

, biologically transmitted by the tsetse fly in Africa, are a major cause of illness resulting in both high morbidity and mortality among humans, cattle, wild ungulates, and other species. However, tsetse fly distributions change rapidly due to environmental changes, and fine-scale distribution maps are few. Due to data scarcity, most presence/absence estimates in Kenya prior to 2000 are a combination of local reports, entomological knowledge, and topographic information. The availability of tsetse fly abundance data are limited, or at least have not been collected into aggregate, publicly available national datasets. Despite this limitation, other avenues exist for estimating tsetse distributions including remotely sensed data, climate information, and statistical tools.Here we present a logistic regression model of tsetse abundance. The goal of this model is to estimate the distribution of tsetse fly in Kenya in the year 2000, and to provide a method by which to anticipate their future distribution. Multiple predictor variables were tested for significance and for predictive power; ultimately, a parsimonious subset of variables was identified and used to construct the regression model with the 1973 tsetse map. These data were validated against year 2000 Food and Agriculture Organization (FAO) estimates. Mapcurves Goodness-Of-Fit scores were used to evaluate the modeled fly distribution against FAO estimates and against 1973 presence/absence data, each driven by appropriate climate data.Logistic regression can be effectively used to produce a model that projects fly abundance under elevated greenhouse gas scenarios. This model identifies potential areas for tsetse abandonment and expansion