38 research outputs found
InâHerd Diversity of Lifetime Performances: A Key for the Sustainability of Livestock Farming System Based on Grassland
Plasmodium falciparum parasite population structure and gene flow associated to anti-malarial drugs resistance in Cambodia
Background: Western Cambodia is recognized as the epicentre of emergence of Plasmodium falciparum multi-drug resistance. The emergence of artemisinin resistance has been observed in this area since 2008â2009 and molecular signatures associated to artemisinin resistance have been characterized in k13 gene. At present, one of the major threats faced, is the possible spread of Asian artemisinin resistant parasites over the world threatening millions of people and jeopardizing malaria elimination programme efforts. To anticipate the diffusion of artemisinin resistance, the identification of the P. falciparum population structure and the gene flow among the parasite population in Cambodia are essential. Methods: To this end, a mid-throughput PCR-LDR-FMA approach based on LUMINEX technology was developed to screen for genetic barcode in 533 blood samples collected in 2010â2011 from 16 health centres in malaria endemics areas in Cambodia. Results: Based on successful typing of 282 samples, subpopulations were characterized along the borders of the country. Each 11-loci barcode provides evidence supporting allele distribution gradient related to subpopulations and gene flow. The 11-loci barcode successfully identifies recently emerging parasite subpopulations in western Cambodia that are associated with the C580Y dominant allele for artemisinin resistance in k13 gene. A subpopulation was identified in northern Cambodia that was associated to artemisinin (R539T resistant allele of k13 gene) and mefloquine resistance. Conclusions: The gene flow between these subpopulations might have driven the spread of artemisinin resistance over Cambodia
Plasmodium vivax dhfr and dhps mutations in isolates from Madagascar and therapeutic response to sulphadoxine-pyrimethamine
<p>Abstract</p> <p>Background</p> <p>Four of five <it>Plasmodium </it>species infecting humans are present in Madagascar. <it>Plasmodium vivax </it>remains the second most prevalent species, but is understudied. No data is available on its susceptibility to sulphadoxine-pyrimethamine, the drug recommended for intermittent preventive treatment during pregnancy. In this study, the prevalence of <it>P. vivax </it>infection and the polymorphisms in the <it>pvdhfr </it>and <it>pvdhps </it>genes were investigated. The correlation between these polymorphisms and clinical and parasitological responses was also investigated in <it>P. vivax</it>-infected patients.</p> <p>Methods</p> <p><it>Plasmodium vivax </it>clinical isolates were collected in eight sentinel sites from the four major epidemiological areas for malaria across Madagascar in 2006/2007. <it>Pvdhfr </it>and <it>pvdhps </it>genes were sequenced for polymorphism analysis. The therapeutic efficacy of SP in <it>P. vivax </it>infections was assessed in Tsiroanomandidy, in the foothill of the central highlands. An intention-to-treat analysis of treatment outcome was carried out.</p> <p>Results</p> <p>A total of 159 <it>P. vivax </it>samples were sequenced in the <it>pvdhfr/pvdhps </it>genes. Mutant-types in <it>pvdhfr </it>gene were found in 71% of samples, and in <it>pvdhps </it>gene in 16% of samples. Six non-synonymous mutations were identified in <it>pvdhfr</it>, including two novel mutations at codons 21 and 130. For <it>pvdhps</it>, beside the known mutation at codon 383, a new one was found at codon 422. For the two genes, different combinations were ranged from wild-type to quadruple mutant-type. Among the 16 patients enrolled in the sulphadoxine-pyrimethamine clinical trial (28 days of follow-up) and after adjustment by genotyping, 3 (19%, 95% CI: 5%â43%) of them were classified as treatment failure and were <it>pvdhfr </it>58R/117N double mutant carriers with or without the <it>pvdhps </it>383G mutation.</p> <p>Conclusion</p> <p>This study highlights (i) that genotyping in the <it>pvdhfr </it>and <it>pvdhps </it>genes remains a useful tool to monitor the emergence and the spread of <it>P. vivax </it>sulphadoxine-pyrimethamine resistant in order to improve the national antimalarial drug policy, (ii) the issue of using sulphadoxine-pyrimethamine as a monotherapy for intermittent preventive treatment of pregnant women or children.</p
Streptococcus agalactiae clones infecting humans were selected and fixed through the extensive use of tetracycline
Streptococcus agalactiae (Group B Streptococcus, GBS) is a commensal of the digestive and genitourinary tracts of humans that emerged as the leading cause of bacterial neonatal infections in Europe and North America during the 1960s. Due to the lack of epidemiological and genomic data, the reasons for this emergence are unknown. Here we show by comparative genome analysis and phylogenetic reconstruction of 229 isolates that the rise of human GBS infections corresponds to the selection and worldwide dissemination of only a few clones. The parallel expansion of the clones is preceded by the insertion of integrative and conjugative elements conferring tetracycline resistance (TcR). Thus, we propose that the use of tetracycline from 1948 onwards led in humans to the complete replacement of a diverse GBS population by only few TcR clones particularly well adapted to their host, causing the observed emergence of GBS diseases in neonates. \ua9 2014 Macmillan Publishers Limited. All rights reserved
Gangs juvéniles et construits ethniques dans le contexte américain
En nous appuyant sur une revue de la littĂ©rature criminologique essentiellement amĂ©ricaine Ă propos des gangs de rue, nous interrogerons la construction ethnicisante, voire racialiste des conduites dĂ©linquantes collectives des jeunes issus des minoritĂ©s, en prenant lâexemple des gangs afro-amĂ©ricains. Ceci en ramenant cette construction Ă deux lignes dâanalyse dont la premiĂšre est celle du contexte historico-national de production de lâobjet « gangs de rue » et de lâethnicitĂ© qui y est associĂ©e, avec les notions de « relations raciales » et dâ« interethnicité ». La seconde est celle de lâagir ethnique, sâobservant sur les deux faces interne et externe de la communalisation. Câest la construction ethnique de lâindividu dans le rapport quâil entretient avec sa communautĂ© idĂ©elle dâappartenance, sa culture et son histoire, et simultanĂ©ment, le rapport quâil entretient avec les autres, dans un double mouvement de dĂ©signation et dâautodĂ©signation, traçant une frontiĂšre labile, parfois statique, entre les « eux » et les « nous ».Considering an array of mainly North-American scientific works on street gangs, we will examine the ethnicized and racialized construction of minority-issued youth groupsâ offending behaviour, focusing on African-American gangs. We will consider this issue from two points of view. The first one will be the national and historic creation of the « street gang » object/subject and its related ethnicity, combined with notions of racial relationships and inter-ethnicity. The second perspective will study ethnic behaviour in terms of inner and outer communalization. We will study oneâs ethnic construction through oneâs relationship with an ideal community, oneâs culture and history, and simultaneously, the relationship one has with others, in a twofold movement of identification and auto-identification, drawing an indefinite line, sometimes an unwavering one, between « Them » and « Us »
Introducing efïŹciency into the analysis of individual lifetime performance variability: a key to assess herd management
Lifetime performance variability is a powerful tool for evaluating herd management. Although efficiency is a key aspect of performance, it has not been integrated into existing studies on the variability of lifetime performance. The goal of the present article is to analyse the effects of various herd management options on the variability of lifetime performance by integrating criteria relative to feed efficiency. A herd model developed for dairy goat systems was used in three virtual experiments to test the effects of the diet energy level, the segmentation of the feeding plan and the mean production potential of the herd on the variability of lifetime performance. Principal component analysis showed that the variability of lifetime performance was structured around the first axis related to longevity and production and the second related to the variables used in feed efficiency calculation. The intra-management variability was expressed on the first axis (longevity and production), whereas the inter-management variability was expressed on the second axis (feed efficiency) and was mainly influenced by the combination of the diet energy level and the mean production potential. Similar feed efficiencies were attained with different management options. Still, such combinations relied on different biological bases and, at the level of the individual, contrasting results were observed in the relationship between the obtained pattern of performance (in response to diet energy) and the reference pattern of performance (defined by the production potential). Indeed, our results showed that over-feeding interacted with the feeding plan segmentation: a high level of feeding plan segmentation generated a low proportion of individuals at equilibrium with their production potential, whereas a single ration generated a larger proportion. At the herd level, the diet energy level and the herd production potential had marked effects on production and efficiency due to dilution of fixed production costs (i.e. maintenance requirements). Management options led to similar production and feed efficiencies at the herd level while giving large contrasts in the proportions of individuals at equilibrium with their production potential. These results suggested that analysing individual variability on the basis of criteria related to production processes could improve the assessment of herd management. The herd model opens promising perspectives in studying whether individual variability represents an advantage for herd performance
DiversitĂ© des carriĂšres des chĂšvres laitiĂšres et pratiques dâalimentation et de reproduction : approche par modĂ©lisation
Herd ability to achieve the farmerâs production project despite perturbations is a key element of herd performance. It invites analysing in-herd diversity of lifetime performances in order to evaluate the effects of management practices on herd robustness. However, to date a few studies have analysed the role of this diversity. Such analysis requires the development of a model simulating feeding and reproduction strategies and their effects on individual responses. The simulator developed in this paper for a dairy goat herd integrates a biological system (individual performance) and a decisional system (management practices). The biological system integrates a simple representation of the biological basis for individual variability. The decisional system is based on a generic structure that makes it possible to represent a range of feeding and reproduction practices and the corresponding strategy for management of individuals into groups. The simulator was used to compare two options for infertility management. The first one restricts diversity by systematic culling for infertility (option n°1). The second one allows diversity by maintaining females in lactation after a reproductive failure (option n°2). Simulation results show that in case of fertility decline, herd production decrease is less important for option n°2 where the increase of the proportion of females in extended lactation makes it possible to buffer the perturbation. These first results highlight the interest of the lifetime performance approach in order to evaluate herd performances. The simulator opens interesting perspectives to explore management scenarios that increase feed autonomy of the herd and more generally which can lead to a change in intensification level of farming systems.La capacitĂ© du troupeau Ă rĂ©pondre au projet de production de lâĂ©leveur en dĂ©pit de perturbations est un Ă©lĂ©ment essentiel de la performance du troupeau. Elle demande dâanalyser la diversitĂ© des carriĂšres de femelles pour Ă©valuer lâeffet des pratiques sur la capacitĂ© de rĂ©sistance du troupeau aux perturbations. Cependant Ă ce jour peu dâĂ©tudes ont analysĂ© le rĂŽle de cette diversitĂ©. Cette analyse nĂ©cessite le dĂ©veloppement dâun modĂšle simulant les stratĂ©gies dâalimentation et de reproduction traduisant le projet de production de lâĂ©leveur et leurs effets sur les rĂ©ponses individuelles. Le simulateur dĂ©veloppĂ© pour un troupeau caprin laitier couple un systĂšme biologique (Ă©laboration de la performance individuelle) et un systĂšme dĂ©cisionnel (Ă©laboration des pratiques de conduite). Le systĂšme biologique intĂšgre de façon simple les bases biologiques de la variabilitĂ© des rĂ©ponses individuelles. Le systĂšme dĂ©cisionnel repose sur une structure gĂ©nĂ©rique reprĂ©sentant une gamme de pratiques dâalimentation et de reproduction ainsi que la stratĂ©gie dâallotement qui en dĂ©coule. Le simulateur a Ă©tĂ© utilisĂ© pour comparer deux options de gestion des Ă©checs de reproduction, lâune diminuant la diversitĂ© en rĂ©formant systĂ©matiquement aprĂšs Ă©chec Ă la lutte (option n°1) et lâautre favorisant la diversitĂ© des carriĂšres en maintenant les chĂšvres en lactation aprĂšs Ă©chec (option n°2). Les rĂ©sultats des simulations montrent que lors dâune baisse de fertilitĂ©, la baisse de production laitiĂšre du troupeau est moins importante pour lâoption n°2 oĂč lâaugmentation de la proportion de femelles en lactation longue permet dâamortir la perturbation. Ces premiers rĂ©sultats montrent lâintĂ©rĂȘt de lâapproche par les carriĂšres de femelles pour Ă©valuer les performances du troupeau. Le simulateur ouvre des perspectives pour explorer des scĂ©narios de conduite qui accroissent lâautonomie alimentaire du troupeau et qui plus gĂ©nĂ©ralement peuvent permettre une Ă©volution du niveau dâintensification des systĂšmes de production
Le développement professionnel d'enseignants porteurs d'innovation pédagogique dans une université française : Y-a-t-il eu transformation ? (Working Paper)
Nous analysons l'expĂ©rience d'enseignants porteurs d'un projet d'innovation pĂ©dagogique Ă l'universitĂ© afin de mieux comprendre leur vĂ©cu et leur Ă©ventuel sentiment de transformation Ă la suite du projet. Une enquĂȘte par questionnaire a Ă©tĂ© rĂ©alisĂ©e auprĂšs de 21 enseignants porteurs d'un projet d'innovation pĂ©dagogique sur la pĂ©riode 2018-2020 dans une universitĂ© française. Les rĂ©sultats, produits selon une approche mixte (analyse thĂ©matique et comptage d'occurrences) ont permis de mettre en Ă©vidence des ressorts motivationnels tournĂ©s vers les besoins du public Ă©tudiant, la reconnaissance professionnelle ou la rĂ©alisation de soi. Les enseignants ont dĂ©crit des facteurs positifs et nĂ©gatifs ayant impactĂ© la rĂ©alisation des projets, ainsi qu'un sentiment nuancĂ© de transformation. Si de nombreux enseignants perçoivent une Ă©volution de leurs pratiques, ils ne considĂšrent pas tous avoir Ă©tĂ© transformĂ©s par le projet
Innovation pĂ©dagogique Ă lâuniversitĂ© et effets de transformation sur les enseignants1
International audienceNous analysons lâexpĂ©rience dâenseignants porteurs dâun projet dâinnovation pĂ©dagogique Ă lâuniversitĂ© afin de mieux comprendre leur vĂ©cu et leur Ă©ventuel sentiment de transformation. Une enquĂȘte par questionnaire a Ă©tĂ© rĂ©alisĂ©e auprĂšs de 21 enseignants porteurs dâun projet dâinnovation pĂ©dagogique sur la pĂ©riode 2018-2020 dans une universitĂ© française. Les rĂ©sultats, produits selon une approche mixte (analyse thĂ©matique et comptage dâoccurrences) ont permis de mettre en Ă©vidence des ressorts motivationnels tournĂ©s vers les besoins du public Ă©tudiant, la reconnaissance professionnelle ou la rĂ©alisation de soi. Les enseignants ont dĂ©crit des facteurs positifs et nĂ©gatifs ayant impactĂ© la rĂ©alisation des projets, ainsi quâun sentiment nuancĂ© de transformation. Si ces derniers perçoivent une Ă©volution de leurs pratiques, ils ne considĂšrent pas tous avoir Ă©tĂ© transformĂ©s par le projet
Innovation pĂ©dagogique Ă lâuniversitĂ© et effets de transformation sur les enseignants1
International audienceNous analysons lâexpĂ©rience dâenseignants porteurs dâun projet dâinnovation pĂ©dagogique Ă lâuniversitĂ© afin de mieux comprendre leur vĂ©cu et leur Ă©ventuel sentiment de transformation. Une enquĂȘte par questionnaire a Ă©tĂ© rĂ©alisĂ©e auprĂšs de 21 enseignants porteurs dâun projet dâinnovation pĂ©dagogique sur la pĂ©riode 2018-2020 dans une universitĂ© française. Les rĂ©sultats, produits selon une approche mixte (analyse thĂ©matique et comptage dâoccurrences) ont permis de mettre en Ă©vidence des ressorts motivationnels tournĂ©s vers les besoins du public Ă©tudiant, la reconnaissance professionnelle ou la rĂ©alisation de soi. Les enseignants ont dĂ©crit des facteurs positifs et nĂ©gatifs ayant impactĂ© la rĂ©alisation des projets, ainsi quâun sentiment nuancĂ© de transformation. Si ces derniers perçoivent une Ă©volution de leurs pratiques, ils ne considĂšrent pas tous avoir Ă©tĂ© transformĂ©s par le projet