Economics in West African Irrigated-Rice Production

The main objective of this investigation is to contribute to the ongoing debate on the effects of the West African Economic and Monetary Union (WAEMU), common external tariff (CET) measures on the competitiveness of the irrigated-rice production system in Niger. The policy analysis matrix (PAM) approach was used to evaluate the various policy effects, based on farm-level, postharvest and rice-marketing data, as well as the financial and economic parity prices of different brands of imported-rice. Results from the PAM base-scenario model showed that under the evaluated CET policy irrigated rice production, activities were competitive and private operators had positive financial gains, meaning that private profitability was positive. Moreover, the irrigated-rice production enterprise revealed positive economic profitability for both retailers and wholesalers. Thus, it generated a net positive income for the national economy per unit of land devoted to this activity. One can argue that the irrigated rice system under the CET was generally competitive (positive private profitability) and had a potential for growth (positive economic profitability). Despite its competitiveness and efficiency, the irrigated rice production system still performs below potential because it lacks additional incentives. Some sensitivity analyses were performed with single-factor and simultaneous changes of several factors, which confirmed the necessity of providing further incentives to the system. The research results suggest that greater incentives should be given in terms of improving marketing channels, especially for retail rice marketing in which a great number of women rice traders are active.L'étude vise à contribuer au débat relatif aux effets du tarif extérieur commun (TEC) de l'Union économique et monétaire Ouest-Africaine (UEMOA) sur la compétitivité du riz irrigué au Niger. La Matrice d'analyse des politiques (MAP) a été utilisé pour évaluer les différents effets, sur la base de données relatives à l'exploitation agricole, les activités post-récolte, la commercialisation, ainsi que les prix paritaires financiers et économiques de différents types de riz importés. Avec le TEC, les résultats du modèle de base de la MAP ont montré que la production de riz irrigué a été compétitive et que les acteurs de la chaîne de valeurs ont bénéficié de gains financiers importants (rentabilité financière positive). Par ailleurs, la production de riz irrigué a été une activité économiquement rentable, aussi bien pour les commerçants-détaillants que pour les grossistes. Par conséquent, par unité de terre dévolue à cette activité, le riz irrigué a généré des revenus pour l'économie nationale. Avec le TEC, le système de production de riz irrigué a été généralement compétitif (rentabilité financière positive) et a eu un bon potentiel de croissance économique (rentabilité économique positive). Cependant, malgré, sa compétitivité et son efficacité, la performance du système de production de riz irrigué reste en deçà de son potentiel, du fait du manque d'incitations additionnelles. Des analyses de sensibilité ont été effectuées avec le changement de niveau d'un seul facteur, et de plusieurs facteurs à la fois. Ces analyses confirment la nécessité de mesures incitatives, en termes d'amélioration des circuits de commercialisation, notamment le circuit des détaillants qui implique un nombre assez important de commerçantes.Mots clés: Analyse des politiques, production de riz irrigué, avantage comparatif, rentabilité économique, rentabilité financièr

Aggravation de l’anémie et polymorphisme de l’haptoglobine au cours de la drépanocytose au Sénégal

La drépanocytose homozygote s’accompagne d’une augmentation de l’hémoglobine (Hb) plasmatique, susceptible d’exposer les hématies à un stress oxydant. L’haptoglobine présente trois phénotypes majeurs (Hp1-1, Hp 2-1 et Hp 2-2) susceptibles de fixer l’hémoglobine extracellulaire avec une efficacité différente. L’objectif de ce travail est de voir si la connaissance du phénotype d’Hp pouvait constituer un élément prédictifde l’anémie sévère. Pour cela, il a été recruté 68 drépanocytaires  homozygotes, âgés de 5 à 31 ans. Pour chaque patient, un témoin de même sexe et de même âge ± 2 ans a été recruté. Le phénotypage de l’Hp a été réalisé par électrophorèse sur gel de polyacrylamide. Les résultats du dosage de l’Hb font ressortir que les taux d’Hb sont significativement différentes chez les patients comparées à celles des témoins (p = 0,001). Lorsque la répartition a été faite en fonction du phénotype d’Hp, une différence statistiquement significative a étéretrouvée entre le phénotype Hp1-1 et le phénotype Hp2-2 (p < 0,001) chez les patients et non chez les témoins. Les résultats de cette étude préliminaire suggéreraient que la connaissance du phénotype d’Hp seraitun facteur prédictif de l’anémie sévère au cours de la drépanocytose.Mots clés : Drépanocytose, anémie, phénotypes d’haptoglobine

An Inhibitory Antibody Blocks Interactions between Components of the Malarial Invasion Machinery

Host cell invasion by apicomplexan pathogens such as the malaria parasite Plasmodium spp. and Toxoplasma gondii involves discharge of proteins from secretory organelles called micronemes and rhoptries. In Toxoplasma a protein complex comprising the microneme apical membrane antigen 1 (AMA1), two rhoptry neck proteins, and a protein called Ts4705, localises to the moving junction, a region of close apposition between parasite and host cell during invasion. Antibodies against AMA1 prevent invasion and are protective in vivo, and so AMA1 is of widespread interest as a malaria vaccine candidate. Here we report that the AMA1 complex identified in Toxoplasma is conserved in Plasmodium falciparum. We demonstrate that the invasion-inhibitory monoclonal antibody (mAb) 4G2, which recognises P. falciparum AMA1 (PfAMA1), cannot bind when PfAMA1 is in a complex with its partner proteins. We further show that a single completely conserved PfAMA1 residue, Tyr251, lying within a conserved hydrophobic groove adjacent to the mAb 4G2 epitope, is required for complex formation. We propose that mAb 4G2 inhibits invasion by preventing PfAMA1 from interacting with other components of the invasion complex. Our findings should aid the rational design of subunit malaria vaccines based on PfAMA1

Mind the (yield) gap(s)

This paper explores the origin of the notion of “yield gap” and its use as a framing device for agricultural policy in sub-Saharan Africa. The argument is that while the yield gap of policy discourse provides a simple and powerful framing device, it is most often used without the discipline or caveats associated with the best examples of its use in crop production ecology and microeconomics. This argument is developed by examining how yield gap is used in a selection of recent and influential agricultural policy documents. The message for policy makers and others is clear: “mind the (yield) gap(s)”, for they are seldom what they appear

Social-ecological outcomes of agricultural intensification

Land-use intensification in agrarian landscapes is seen as a key strategy to simultaneously feed humanity and use ecosystems sustainably, but the conditions that support positive social-ecological outcomes remain poorly documented. We address this knowledge gap by synthesizing research that analyses how agricultural intensification affects both ecosystem services and human well-being in low- and middle-income countries. Overall, we find that agricultural intensification is rarely found to lead to simultaneous positive ecosystem service and well-being outcomes. This is particularly the case when ecosystem services other than food provisioning are taken into consideration

Linkage Mapping of Stem Saccharification Digestibility in Rice

Rice is the staple food of almost half of the world population, and in excess 90% of it is grown and consumed in Asia, but the disposal of rice straw poses a problem for farmers, who often burn it in the fields, causing health and environmental problems. However, with increased focus on the development of sustainable biofuel production, rice straw has been recognized as a potential feedstock for non-food derived biofuel production. Currently, the commercial realization of rice as a biofuel feedstock is constrained by the high cost of industrial saccharification processes needed to release sugar for fermentation. This study is focused on the alteration of lignin content, and cell wall chemotypes and structures, and their effects on the saccharification potential of rice lignocellulosic biomass. A recombinant inbred lines (RILs) population derived from a cross between the lowland rice variety IR1552 and the upland rice variety Azucena with 271 molecular markers for quantitative trait SNP (QTS) analyses was used. After association analysis of 271 markers for saccharification potential, 1 locus and 4 pairs of epistatic loci were found to contribute to the enzymatic digestibility phenotype, and an inverse relationship between reducing sugar and lignin content in these recombinant inbred lines was identified. As a result of QTS analyses, several cell-wall associated candidate genes are proposed that may be useful for marker-assisted breeding and may aid breeders to produce potential high saccharification rice varieties

Contrasting Transcriptional Responses of a Virulent and an Attenuated Strain of Mycobacterium tuberculosis Infecting Macrophages

Along with the recent identification of single nucleotide polymorphisms in H37Ra when compared to H37Rv, our demonstration of differential expression of PhoP-regulated and ESX-1 region-related genes during macrophage infection further highlights the significance of these genes in the attenuation of H37Ra

Complications de l’appendicectomie chez l’enfant

Le but de ce travail est de rapporter les complications de l’appendicectomie chez  l’enfant. Ce travail est une étude rétrospective réalisée au service de Chirurgie Pédiatrique du Centre Hospitalier Universitaire Aristide Le Dantec, durant la période du 1er mars 2007 au 31 décembre 2011. Elle a concerné 123 patients âgés de moins de 16 ans, ayant bénéficié d’une appendicectomie pour appendicite aiguë ou compliquée. Nous avons évalué les facteurs qui pourraient intervenir dans la survenue de complications postopératoires : il s’agit de l’âge, du sexe, de  l’indication opératoire, du score ASA et du type de chirurgie selon la classification d’Altemeier. Trente-neuf complications ont été répertoriées chez 37 patients, soit une morbidité de 30,1%. Les infections du site opératoire étaient représentées par 6 cas d’abcès de paroi, soit 15,4% et 19 cas de suppurations de la plaie opératoire, soit 48,7%. Le taux de mortalité post-opératoire était de 2,4% (3 patients). Les malades opérés pour appendicite compliquée faisaient plus de complications  post-opératoires que ceux opérés pour appendicite aiguë (p = 0,02). Chez les patients ASA I, il y avait moins de patients avec complications (p = 0,04); par  contre chez les patients ASA II, y avait plus de patients avec complications (p = 0,08). Pour la chirurgie septique, il y avait plus de patients avec complications (p=0,13) de même que pour la chirurgie contaminée (p = 0,97). Les complications après appendicectomies chez l’enfant sont fréquentes dans notre contexte africain. Ces complications surviennent d’autant plus qu’il s’agit d’une forme compliquée d’appendicite et sont dominées par les suppurations pariétales.Mots clés : appendicectomies ; enfant ; complications ; infections.To describe the complications after appendectomy in children. This study is a  retrospective study in pediatric surgery  department of the Centre Hospitalier Universitaire Aristide Le Dantec, during the period 1 March 2007 to 31 December  2011. It involved 123 patients aged under 16, who underwent an appendectomy for acute or complicated appendicitis. We evaluated the factors that may be involved in the occurrence of postoperative complications: it's age, gender, indication for  surgery, ASA score and the type of surgery according to the classification  Altemeier. Thirty-nine complications were identified in 37 patients, a morbidity of 30.1%. The surgical site infections were represented by 6 cases of wound infection,15.4% and 19 cases of suppuration of the wound, or 48.7%. The rate of  postoperative mortality was 2.4% (3 patients). Patients operated for complicated appendicitis were more postoperative complications than surgery for acute  appendicitis (p = 0.02). In ASA I patients, there were fewer patients with  complications (p = 0.04); by cons in ASA II patients, there were more patients with complications (p = 0.08). For dirty surgery, there were more patients with complications (p = 0.13) and for the contaminated surgery (p = 0.97). Complications after appendectomy in children are common in our African context. These complications occur especially since it is a complicated form of appendicitis and are dominated by parietal suppuration.Keywords: appendectomies ; child ; complications ; infections

Effect of drought on Oryza glaberrima rice accessions and Oriza glaberrima derived-lines

Rice varieties response to drought has been extensively studied and many lines have been released, but identifying new tolerant lines is still a challenge for scientists due to the complexity and the specificity of this constraint over environments. Three sets of field experiments were conducted between 2006 and 2008 at Africa Rice Center research station, Togoudo, Benin to evaluate the effect of drought on some traits of rice (Oryza sp.). Three genotype types including 202 interspecific lines, from a cross between WAB56-104 (O. sativa subsp. japonica) and CG14 (O. glaberrima), adapted to upland conditions, 60 chromosome segment substitution lines made for lowland conditions and 211 accessions of O. glaberrima Steud., were evaluated using a split plot design replicated twice or thrice and an alpha lattice design with four blocks. There was a consistent negative effect of drought on plant height and grain yield across genotypes drought-tolerance levels and across genotype/types. Plant height and grain yield were more reduced for sensitive genotypes than for moderately tolerant and tolerant genotypes. Flowering and maturity were consistently delayed across genotype types and tolerance levels. Mean delays of 6.5, 21.8 and 9.4 days were observed for start, 50 and 100% flowering, respectively. Maturity was also delayed, with consistency across genotype types. However, no clear picture of drought effect on flowering and maturity was observed in terms of differences among drought-tolerance levels. The effects of drought on the number of tillers and on leaf temperature were not consistent. Plant height and grain yield showed the clearest differences between genotype-tolerance levels. Genotypes 151-3-8, 104-3-5, 116-2-4, 117-2-6, MPL-15-3, MPL-202-3, SENL-21-2, SENL-10-1, SENL-17-2, SENL-26-3, TOG5691, TOG6679 and TOG5591 yielded higher than the parents and checks