439 research outputs found

    Ultrasonographic assessment of urinary tract lesions due to Schistosoma haematobium in Niger after four consecutive years of treatment with praziquantel

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    Une étude comparative sur l'étendue des lésions du tractus urinaire détectées par échographie a été entreprise dans 2 villages du Niger situés près de périmètres irrigués. La prévalence de la schistosomiase urinaire était respectivement de 64,3 % et de 58,8 %. Après un traitement au praziquantel de 4 années consécutives, les lésions vésicales atteignaient 20 % dans le village traité et 54 % dans le témoin, les lésions rénales 6 % dans le village traité et 36 % dans le témoin. Ces résultats montrent que la morbidité de la schistosomiase urinaire peut être réduite par un traitement annuel sur plusieurs années sans autre forme d'interventio

    On the nature of the hard X-ray sources SWIFTJ1907.3-2050, IGRJ12123-5802 and IGRJ19552+0044

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    The INTEGRAL and Swift hard X-ray surveys have identified a large number of new sources, among which many are proposed as Cataclysmic Variables (CVs). Here we present the first detailed study of three X-ray selected CVs, Swift J1907.3-2050, IGRJ12123-5802, and IGRJ19552+0044 based on XMM-Newton, Suzaku, Swift observations and ground based optical and archival nIR/IR data. Swift J1907.3-2050 is highly variable from hours to months-years at all wavelengths. No coherent X-ray pulses are detected but rather transient features. The X-ray spectrum reveals a multi-temperature optically thin plasma absorbed by complex neutral material and a soft black body component arising from a small area. These characteristics are remarkably similar to those observed in magnetic CVs. A supra-solar abundance of nitrogen could arise from nuclear processed material from the donor star. Swift J1907.3-2050 could be a peculiar magnetic CV with the second longest (20.82 h) binary period. IGRJ12123-5802 is variable in the X-rays on a timescale of ~7.6 h. No coherent pulsations are detected, but its spectral characteristics suggest that it could be a magnetic CV of the Intermediate Polar (IP) type. IGRJ19552+0044 shows two X-ray periods, 1.38 h and 1.69 h and a X-ray spectrum characterized by a multi-temperature plasma with little absorption.We derive a low accretion rate, consistent with a CV below the orbital period gap. Its peculiar nIR/IR spectrum suggests a contribution from cyclotron emission. It could either be a pre-polar or an IP with the lowest degree of asynchronism.Comment: Accepted for publication in MNRAS. 14 pages, 11 figures, 5 table

    Assessing bundles of ecosystem services from regional to landscape scale: Insights from the French Alps

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    Copyright © 2015 The Authors. Journal of Applied Ecology © 2015 British Ecological SocietyAssessments of ecosystem services (ES) and biodiversity (hereafter ecological parameters) provide a comprehensive view of the links between landscapes, ecosystem functioning and human well-being. The investigation of consistent associations between ecological parameters, called bundles, and of their links to landscape composition and structure is essential to inform management and policy, yet it is still in its infancy. We mapped over the French Alps an unprecedented array of 18 ecological parameters (16 ES and two biodiversity parameters) and explored their co-occurrence patterns underpinning the supply of multiple ecosystem services in landscapes. We followed a three-step analytical framework to i) detect the ES and biodiversity associations relevant at regional scale, ii) identify the clusters supplying consistent bundles of ES at subregional scale and iii) explore the links between landscape heterogeneity and ecological parameter associations at landscape scale. We used successive correlation coefficients, overlap values and self-organizing maps to characterize ecological bundles specific to given land cover types and geographical areas of varying biophysical characteristics and human uses at nested scales from regional to local. The joint analysis of land cover richness and ES gamma diversity demonstrated that local landscape heterogeneity alone did not imply compatibility across multiple ecosystem services, as some homogeneous landscape could supply multiple ecosystem services. Synthesis and applications. Bundles of ecosystem services and biodiversity parameters are shaped by the joint effects of biophysical characteristics and of human history. Due to spatial congruence and to underlying functional interdependencies, ecological parameters should be managed as bundles even when management targets specific objectives. Moreover, depending on the abiotic context, the supply of multiple ecosystem services can arise either from deliberate management in homogeneous landscapes or from spatial heterogeneity.ERAnet BiodivERsA project CONNECTFrench Agence Nationale pour la RechercheEU project VOLANT

    Signatures of chaotic tunnelling

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    Recent experiments with cold atoms provide a significant step toward a better understanding of tunnelling when irregular dynamics is present at the classical level. In this paper, we lay out numerical studies which shed light on the previous experiments, help to clarify the underlying physics and have the ambition to be guidelines for future experiments.Comment: 11 pages, 9 figures, submitted to Phys. Rev. E. Figures of better quality can be found at http://www.phys.univ-tours.fr/~mouchet
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