664 research outputs found

    Sur les différentielles de torsion

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    Foetal scalp blood sampling during labour for pH and lactate measurements

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    Second-line methods of foetal monitoring have been developed in an attempt to reduce unnecessary interventions due to continuous cardiotocography (CTG), and to better identify foetuses that are at risk of intrapartum asphyxia.Very few studies directly compared CTG with foetal scalp blood (FBS) and CTG only. Only one randomised controlled trial (RCT) was published in the 1970s and had limited power to assess neonatal outcome. Direct and indirect comparisons conclude that FBS could reduce the number of caesarean deliveries associated with the use of continuous CTG.The main drawbacks of FBS are its invasive and discontinuous nature and the need for a sufficient volume of foetal blood for analysis, especially for pH measurement, resulting in failure rates reaching 10%. FBS for lactate measurement became popular with the design of test-strip devices, requiring <0.5 mL of foetal blood. RCTs showed similar outcomes with the use of FBS for lactates compared with pH in terms of obstetrical interventions and neonatal outcomes.In conclusion, there is some evidence that FBS reduces the need for operative deliveries. However, the evidence is limited with regard to actual standards, and large RCTs, directly comparing CTG only with CTG with FBS, are still needed

    In situ S‐isotope compositions of sulfate and sulfide from the 3.2 Ga Moodies Group, South Africa: A record of oxidative sulfur cycling

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    Sulfate minerals are rare in the Archean rock record and largely restricted to the occurrence of barite (BaSO4). The origin of this barite remains controversially debated. The mass‐independent fractionation of sulfur isotopes in these and other Archean sedimentary rocks suggests that photolysis of volcanic aerosols in an oxygen‐poor atmosphere played an important role in their formation. Here, we report on the multiple sulfur isotopic composition of sedimentary anhydrite in the ca. 3.22 Ga Moodies Group of the Barberton Greenstone Belt, southern Africa. Anhydrite occurs, together with barite and pyrite, in regionally traceable beds that formed in fluvial settings. Variable abundances of barite versus anhydrite reflect changes in sulfate enrichment by evaporitic concentration across orders of magnitude in an arid, nearshore terrestrial environment, periodically replenished by influxes of seawater. The multiple S‐isotope compositions of anhydrite and pyrite are consistent with microbial sulfate reduction. S‐isotope signatures in barite suggest an additional oxidative sulfate source probably derived from continental weathering of sulfide possibly enhanced by microbial sulfur oxidation. Although depositional environments of Moodies sulfate minerals differ strongly from marine barite deposits, their sulfur isotopic composition is similar and most likely reflects a primary isotopic signature. The data indicate that a constant input of small portions of oxidized sulfur from the continents into the ocean may have contributed to the observed long‐term increase in Δ33Ssulfate values through the Paleoarchean.Centre National de la Recherche ScientifiqueDeutsche ForschungsgemeinschaftH2020 European Research Counci

    Gestion et mise en valeur touristique des sites naturels dans les Bouches-du-Rhône (Schéma départemental du tourisme et des loisirs).

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    Le contexte : des sites nombreux et riches mais touristiquement mal exploités, mal protégés, mal valorisés. Les orientations préconisées dans le cadre du second Schéma Départemental de Développement du Tourisme et des Loisirs

    Field margins enhance weed seed predation in adjacent fields in early spring

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    Seed depletion by granivorous organisms can regulate weeds in arable agriculture. Enhancing this regulation can be achieved by adopting farming practices that favour seed predators. Here, we test the hypothesis that the presence of grassy field margins along field edges will increase in-field weed seed predation, in comparison to situations where no grassy field margin is present. Predation cards with Poa annua were exposed in 15 wheat fields in May and June 2018 along 57 transects at distances of 4, 8, 16, 32 meters from the field edge. Cards were either caged (predation by invertebrates) or uncaged predation byall seed predators). We found that in May, the presence of grassy field margins led to higher in-field predation rates at all distances from the field edge, with a very high contribution of invertebrates to seed predation. In June, the presence of grass margin had no impact on in-field seed predation, to which invertebrates and vertebrates contributed equally. This preliminary study provides some support to the hypothesis that grassy field margins augment in-field weed seed predation in early spring. It is plausible that these habitats are emergence sites for invertebrates, with a subsequent high abundance of adults nearby grass margins in early spring, before they disperse more widely across fields and/or switch to alternative prey. These results call for further comparative research on the impact of grass margins on seed predation, seed predators and alternative prey during the whole cropping season

    Inherited geochemical diversity of 3.4 Ga organic films from the Buck Reef Chert, South Africa

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    International audienceArchean rocks contain crucial information about the earliest life forms on Earth, but documenting these early stages of biological evolution remains challenging. The main issue lies in the geochemical transformations experienced by Archean organic matter through its multibillion-year geological history. Here we present spatially resolved chemical investigations conducted on 3.4 Ga organic films from the Buck Reef Chert, South Africa which indicate that they possess significantly different chemical compositions. Since these organic films allunderwent the same post-depositional geological history, this geochemical diversity is most likely inherited, reflecting original chemical differences which were not completely obliterated by subsequent burial-induced degradation processes. These results demonstrate that earlyArchean organic films carry chemical information directly related to their original molecular compositions. This paves the way for the reconstruction of the initial chemical nature of organic microfossils found in ancient rocks, provided that the geologically-induced chemicaltransformations they underwent are properly constrained

    Risk of invasive breast cancer after lobular intra-epithelial neoplasia: Review of the literature

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    International audienceLobular intraepithelial neoplasia (LIN) is a rare breast disease that has been regarded alternately as a risk factor for invasive breast cancer in both breasts or a true breast cancer precursor. The controversy is largely dependent on the estimation of the IBC (Invasive Breast Cancer) risk after LIN; however a systematic review of the published data has not been previously performed. We aimed to review the IBC after LIN and the characteristics of those cancers
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