Search

International audience; Depuis les années 2010, le Cameroun a vu se multiplier les interventions internationales visant à répondre aux déplacements forcés sur son territoire. Prenant l'exemple du secteur éducatif, cette étude interroge les liens et conséquences de ces interventions sur les acteurs et enjeux politiques, à différentes échelles. Le secteur préscolaire, tout d'abord, est réinvesti par les acteurs locaux grâce à des programmes d'aide d'urgence influençant la politique nationale de décentralisation ainsi que l'orientation des stratégies gouvernementales. L'étude de la crise anglophone souligne un processus d'humanitarisation de l'école primaire, visant à dépolitiser un conflit national en neutralisant les enjeux qui lui sont attachés. Enfin, l'exemple d'un projet de formation professionnelle permet d'analyser la manière dont acteurs étatiques, humanitaires et réfugiés s'accommodent d'un environnement politique et de ses contraintes.

The central nervous system of the cephalochordate amphioxus consists of a dorsal neural tube with an anterior brain. Two decades of gene expression analyses in developing amphioxus embryos have shown that, despite apparent morphological simplicity, the amphioxus neural tube is highly regionalised at the molecular level. However, little is known about the morphogenetic mechanisms regulating the spatiotemporal emergence of cell types at distinct sites of the neural axis and how their arrangements contribute to the overall neural architecture. In vertebrates, proliferation is key to provide appropriate cell numbers of specific types to particular areas of the nervous system as development proceeds, but in amphioxus proliferation has never been studied at this level of detail, nor in the specific context of neurogenesis. Here, we describe the dynamics of cell division during the formation of the central nervous system in amphioxus embryos, and identify specific regions of the nervous system that depend on proliferation of neuronal precursors at precise time-points for their maturation. By labelling proliferating cells in vivo at specific time points in development, and inhibiting cell division during neurulation, we demonstrate that localised proliferation in the anterior cerebral vesicle is required to establish the full cell type repertoire of the frontal eye complex and the putative hypothalamic region of the amphioxus brain, while posterior proliferating progenitors, which were found here to derive from the dorsal lip of the blastopore, contribute to elongation of the caudal floor plate. Between these proliferative domains, we find that trunk nervous system differentiation is independent from cell division, in which proliferation decreases during neurulation and resumes at the early larval stage. Taken together, our results highlight the importance of proliferation as a tightly controlled mechanism for shaping and regionalising the amphioxus neural axis during development, by addition of new cells fated to particular types, or by influencing tissue geometry., Whitten Trust

Purpose: Previous reports have suggested that active exercise aside, intrinsic aerobic running capacity (Low = LCR, high = HCR) in otherwise sedentary animals may influence several cardiovascular health-related indicators. Relative to the HCR phenotype, the LCR phenotype is characterized by decreased endothelial reactivity, increased susceptibility to reperfusion-induced arrhythmias following short, non-infarction ischemia, and increased diet-induced insulin resistance. More broadly, the LCR phenotype has come to be characterized as a “disease prone” model, with the HCRs as “disease resistant.” Whether these effects extend to injury outcomes in an overt infarction or whether the effects are gender specific is not known. This study was designed to determine whether HCR/LCR phenotypic differences would be evident in injury responses to acute myocardial ischemia-reperfusion injury (AIR), measured as infarct size and to determine whether sex differences in infarction size were preserved with phenotypic selection.Methods: Regional myocardial AIR was induced in vivo by either 15 or 30 min ligation of the left anterior descending coronary artery, followed by 2 h of reperfusion. Global ischemia was induced in isolated hearts ex vivo using a Langendorff perfusion system and cessation of perfusion for either 15 or 30 min followed by 2 h of reperfusion. Infarct size was determined using 2, 3, 5–triphenyltetrazolium chloride (TTC) staining, and normalized to area at risk in the regional model, or whole heart in the global model. Portions of the tissue were paraffin embedded for H&E staining and histology analysis.Results: Phenotype dependent differences in infarct size were seen with 15 min occlusion/2 h reperfusion (LCR > HCR, p < 0.05) in both regional and global models. In both models, longer occlusion times (30 min/2 h) produced significantly larger infarctions in both phenotypes, but phenotypic differences were no longer present (LCR vs. HCR, p = n.s.). Sex differences in infarct size were present in each phenotype (LCR male > LCR female, p < 0.05; HCR male > HCR female, p < 0.05 regardless of length of occlusion, or ischemia model.Conclusions: There is cardioprotection afforded by high intrinsic aerobic capacity, but it is not infinite/continuous, and may be overcome with sufficient injury burden. Phenotypic selection based on endurance running capacity preserved sex differences in response to both short and longer term coronary occlusive challenges. Outcomes could not be associated with differences in system characteristics such as circulating inflammatory mediators or autonomic nervous system influences, as similar phenotypic injury patterns were seen in vivo, and in isolated crystalloid perfused heart ex vivo.

An electrochemical-DNA (E-DNA) sensor was constructed by using DNA metallization to produce an electrochemical signal reporter in situ and hybridization chain reaction (HCR) as signal amplification strategy. The cyclic voltammetry (CV) technique was used to characterize the electrochemical solid-state Ag/AgCl process. Moreover, the enzyme cleavage technique was introduced to reduce background signals and further improve recognition accuracy. On the basis of these techniques, the as-prepared E-DNA sensor exhibited superior sensing performance for trace ctDNA analysis with a detection range of 0.5 fM to 10 pM and a detection limit of 7 aM. The proposed E-DNA sensor also displayed excellent selectivity, satisfied repeatability and stability, and had good recovery, all of which supports its potential applications for future clinical sample analysis.

Finding simple and efficient features for offline hand written character recognition is still an active area of research. In this work, we propose modified view based feature extraction approaches for the recognition of handwritten Tamil characters. In the first approach, the five views of a normalized and binarized character image viz, top, bottom, left, right and front are extracted. Each view is then divided into 16 equal zones and the total numbers of background pixel in each zone are counted. The 80 values so obtained form a feature vector. In the second approach, the normalized and binaraized character images are divided into 16 equal zones. Five views are extracted from each zone and the total number of background pixel in each view is counted, resulting in 80 feature values. Further the above two approaches are modified by employing thinned images instead of the whole image. The extracted features are classified using SVM, MLP and ELM classifier. The discriminative powers of the proposed approaches are compared with that of four popular feature extraction approaches in character recognition. The feature extraction time and classification performances are also compared. The proposed modified approaches results in high classification performance (95.26%) with comparatively less feature extraction time.

Currently, 3.2 billion people are at risk of being infected with malaria, with 1.2 billion of those being at high risk (>1 in 1000 chance of getting malaria in a year). Thus, there is a need for a biosensor that is highly sensitive, cost effective, and simple to use for point-of-care diagnosis. The biosensing platform, PathVis, has achieved this by measuring changes in fluid properties after a loop-mediated isothermal amplification (LAMP). LAMP is a DNA amplification system that requires enzymes and a temperature of 65degrees C. LAMP currently limits PathVis by being costly, requiring refrigeration, and difficult to design. We seek to overcome these limitations by replacing this reaction with a non-enzymatic, low-cost, shelf stable, room temperature DNA amplification reaction. The hybridization chain reaction system (HCR) consists of two DNA hairpins that polymerize into long chains in the presence of target DNA. HCR can be designed to grow as linear polymers or branching polymers, the ladder providing exponential signal growth. We have developed an algorithm to generate hairpin systems for a given target DNA sequence. Using this algorithm, we have developed a branching HCR system for detecting malaria. We have found that this algorithm is extremely versatile and can generate hairpin systems for whole chromosomes (>1,000,000 base pairs) in under five minutes. We have found that this malaria detection system theoretically amplifies in the presence of its target; resulting in a system that is ready to be optimized, experimentally tested, and validated on the PathVis biosensing platform.

A DNA variant, rs734232, altering a RUNX1 binding site was recently reported as susceptibility allele at PSORS2 (17q25) in cohorts of psoriasis patients from the US. A testing of this variant in psoriasis patients from Germany did not confirm this association in 300 trios nor in two case-control studies with 281 patients with psoriasis vulgaris and 375 patients with psoriatic arthritis, respectively. These results fail to support rs734232 as a psoriasis susceptibility factor in German psoriasis patients.

La place de l'Égypte dans le système migratoire régional comme pays d'accueil. --L'Égypte est souvent présentée comme un pays d'émigration dans la littérature. Cet article met l'accent sur l'Égypte comme pays d'immigration, plutôt que comme espace de départ. L'auteur explore l'évolution historique de la migration égyptienne en définissant différentes périodes et acteurs politiques qui ont modelé les flux migratoires. Par la suite il analyse les flux d'immigration contemporains ainsi que les politiques migratoires gouvernementales, tant pour les migrants volontaires que forcés. Il aborde également le rôle du HCR concernant les réfugiés et les demandeurs d'asile, ainsi que leurs situations économiques et leurs conditions de vie. The Place of Egypt in the Regional Migration System as a Receiving Country. Egypt is stereotyped as a sending country in the migration literature. This article sheds some light on the position of Egypt as a migration receiving country, rather than a sending country. I explore the historical evolution of the Egyptian migration through defining its phases and the political powers shaping migration streams, and then I explore contemporary immigration streams and the government policies regarding the immigrants; both the voluntary and the forced migration. I also explore the role of the UNHCR and its policies regarding refugees and asylums in Egypt. The economic situation of refugees and their living conditions are investigated. El rol de Egipto en el sistema migratorio regional en calidad de país de acogida. La literatura sobre migraciones considera a menudo a Egipto como un país de emigración. Este artículo presenta, sin embargo, a un Egipto receptor de inmigrantes. El autor explora la evolución histórica de la migración egipcia e identifica los diferentes períodos y actores políticos que han contribuido a modelar los flujos migratorios. Son analizados a continuación los flujos de inmigración contemporáneos y las políticas migratorias gubernamentales dirigidas, tanto a los inmigrantes voluntarios como a los inmigrantes forzosos. Por último, el artículo aborda el rol de las acciones del UNHCR en favor de los refugiados y exiliados en Egipto, así como la situación económica y las condiciones de vida de estos últimos.

The PSORS1 locus in the major histocompatibility complex region is the major genetic determinant for psoriasis vulgaris. Within the PSORS1 region reside at least three potential candidate genes for psoriasis susceptibility. Specific allelic variants of the genes HLA-Cw*6, HCR*WWCC, and CDSN*5 are strongly associated with psoriasis vulgaris and are in strong linkage disequilibrium with each other. We have genotyped the three psoriasis vulgaris susceptibility alleles of the PSORS1 locus in two clinical variants of psoriasis (guttate psoriasis and palmoplantar pustulosis) to study whether PSORS1 is also involved in the pathogenesis of these variants. We also asked whether these two clinical subgroups could help us to distinguish the causative gene within the high-risk PSORS1 haplotype. The association of guttate psoriasis with the three PSORS1 susceptibility alleles was similar and even stronger than seen with psoriasis vulgaris. Palmoplantar pustulosis, however, did not show association with any of the three candidate genes at this locus. Finally, no correlation with the age of onset for disease was observed. Our results show conclusively that psoriasis vulgaris and guttate psoriasis have a similar genetic basis for their association to PSORS1, whereas palmoplantar pustulosis appears to be a distinct disorder.

Working Paper CIRCULEX n°6 -2014; Le séminaire de recherche du 20 mars 2014 est une contribution au programme de recherche CIRCULEX financé par l’ANR. Son objectif a été de montrer comment la thématique « droit de l’Homme » versus humanitaire via la question de la protection des migrations environnementales pénètre le régime du climat. Ce travail s’inscrit dans la Sous Tache 4.3. du programme coordonnée par Christel Cournil.Ce séminaire permet de retracer et questionner 1) le rôle des acteurs de la gouvernance mondiale des migrations environnementales dans la mise à l’agenda de besoin de protection juridique et 2) le processus de fabrication (pré-juridique) de normes internationales. Parmi les experts sur cette question, on retrouve des organisations internationales et les ONG qui défendent les droits de l’Homme des migrants, des réfugiés et des déplacés. Au premier plan, l’OIM et le HCR sont particulièrement présents et investis dans la prise en compte des enjeux environnementaux et des déplacements de population. L’organisation intergouvernementale ICMPD offre également une illustration topique des expertises et plaidoyers engagés pour faire connaître la thématique auprès des États et particulièrement de l’Union européenne.

L’expression “réfugiés environnementaux” a fait officiellement son apparition en 1985 dans un rapport du Programme des Nations Unies pour l'environnement (PNUE). Les réfugiés de l’environnement y sont définis comme “ceux qui sont forcés de quitter leur lieu de vie temporairement ou de façon permanente à cause d’une rupture environnementale (d’origine naturelle ou humaine) qui a mis en péril leur existence ou sérieusement affecté leurs conditions de vie”. Cette définition fait l’objet de vifs ...

International audience