1,188 research outputs found

    Genetic hitchhiking in a subdivided population of Mytilus edulis

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    <p>Abstract</p> <p>Background</p> <p>Few models of genetic hitchhiking in subdivided populations have been developed and the rarity of empirical examples is even more striking. We here provide evidences of genetic hitchhiking in a subdivided population of the marine mussel <it>Mytilus edulis</it>. In the Bay of Biscay (France), a patch of <it>M. edulis </it>populations happens to be separated from its North Sea conspecifics by a wide region occupied only by the sister species <it>M. galloprovincialis</it>. Although genetic differentiation between the two <it>M. edulis </it>regions is largely non-significant at ten marker loci (average F<sub>ST</sub>~0.007), a strong genetic differentiation is observed at a single locus (F<sub>ST </sub>= 0.25). We validated the outlier status of this locus, and analysed DNA sequence polymorphism in order to identify the nature of the selection responsible for the unusual differentiation.</p> <p>Results</p> <p>We first showed that introgression of <it>M. galloprovincialis </it>alleles was very weak in both populations and did not significantly affect their differentiation. Secondly, we observed the genetic signature of a selective sweep within both <it>M. edulis </it>populations in the form of a star-shaped clade of alleles. This clade was nearly fixed in the North Sea and was segregating at a moderate frequency in the Bay of Biscay, explaining their genetic differentiation. Incomplete fixation reveals that selection was not direct on the locus but that the studied sequence recombined with a positively selected allele at a linked locus while it was on its way to fixation. Finally, using a deterministic model we showed that the wave of advance of a favourable allele at a linked locus, when crossing a strong enough barrier to gene flow, generates a step in neutral allele frequencies comparable to the step observed between the two <it>M. edulis </it>populations at the outlier locus. In our case, the position of the barrier is now materialised by a large patch of heterospecific <it>M. galloprovincialis </it>populations.</p> <p>Conclusion</p> <p>High F<sub>ST </sub>outlier loci are usually interpreted as being the consequence of ongoing divergent local adaptation. Combining models and data we show that among-population differentiation can also dramatically increase following a selective sweep in a structured population. Our study illustrates how a striking geographical pattern of neutral diversity can emerge from past indirect hitchhiking selection in a structured population.</p> <p>Note</p> <p>Nucleotide sequences reported in this paper are available in the GenBank™ database under the accession numbers <ext-link ext-link-type="gen" ext-link-id="EU684165">EU684165</ext-link> – <ext-link ext-link-type="gen" ext-link-id="EU684228">EU684228</ext-link>.</p

    The sizes of the exchangeable pools of selenium in elderly women and their relation to institutionalization

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    Exchangeable pools of Se after an intravenous injection of 74Se-enriched isotope as sodium selenite were measured in two groups (n 9) of elderly women (free-living aged 64-82 years and institutionalized aged 68-82 years), and a comparison group (n 9) of young women aged 31-40 years to evaluate the effect of age and institutionalization on Se reserves. Dietary Se intake was not different among the three groups. Plasma Se and glutathione peroxidase (EC 1.11.1.9) levels were significantly lower in the institutionalized elderly women (P < 0.05). In each of the three groups, two pools were determined from our model. The size of the first pool and the sum of the two pools were lower in the group of institutionalized elderly women than in the other two groups. The significant correlation between plasma Se level and total Se pool size (r 0.66, P < 0.01) indicated that this last variable could serve as a new marker of Se status. Finally, these data suggest that the Se status of elderly women is more related to lifestyle, in terms of institutionalization or not, than to age per s

    Method for orthorectification of terrestrial radar maps

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    International audienceThe vehicle-based PELICAN radar system is used in the context of mobile mapping. The R-SLAM algorithm allows simultaneous retrieval of the vehicle trajectory and of the map of the environment. As the purpose of PELICAN is to provide a means for gathering spatial information, the impact of distortion caused by the topography is not negligible. This article proposes an orthorectification process to correct panoramic radar images and the consequent R-SLAM trajectory and radar map. The a priori knowledge of the area topography is provided by a digital elevation model. By applying the method to the data obtained from a path with large variations in altitude it is shown that the corrected panoramic radar images are contracted by the orthorectification process. The efficiency of the orthorectification process is assessed firstly by comparing R-SLAM trajectories to a GPS trajectory and secondly by comparing the position of Ground Control Points on the radar map with their GPS position. The RMS positioning error moves from 5.56 m for the raw radar map to 0.75 m for the orthorectified radar map

    The envelope protein of a human endogenous retrovirus-W family activates innate immunity through CD14/TLR4 and promotes Th1-like responses.: The HERV family MSRV retrovirus activates innate immunity

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    rendre public SVPInternational audienceMultiple sclerosis-associated retroviral element (MSRV) is a retroviral element, the sequence of which served to define the W family of human endogenous retroviruses. MSRV viral particles display proinflammatory activities both in vitro in human mononuclear cell cultures and in vivo in a humanized SCID mice model. To understand the molecular basis of such properties, we have investigated the inflammatory potential of the surface unit of the MSRV envelope protein (ENV-SU), the fraction that is poised to naturally interact with host cells. We report in this study that MSRV ENV-SU induces, in a specific manner, human monocytes to produce major proinflammatory cytokines through engagement of CD14 and TLR4, which are pattern recognition receptors of primary importance in innate immunity. ENV-SU could also trigger a maturation process in human dendritic cells. Finally, ENV-SU endowed dendritic cells with the capacity to support a Th1-like type of Th cell differentiation. The data are discussed in the context of immune responses and chronic proinflammatory disorders

    Les élites de la colonie et de l’Empire à Arles, au début du Principat: nouveaux témoignages épigraphiques

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    Dieser Artikel bietet eine detaillierte Untersuchung von in Arles in Wiederverwendung gefundenen, fragmentarischen Inschriften. Die meisten von ihnen stammen aus den Ausgrabungen der Kryptoportiken des Forums und waren bisher nur kurz angezeigt worden. Eine erste Gruppe beleuchtet die den Angehörigen des Ritterstandes von Arles zu Beginn der Kaiserzeit übertragenen militärischen Kommandofunktionen. Nach der Diskussion von drei bereits bekannten Dokumenten werden zwei Texte untersucht, die militärische Funktionen erwähnen, die erstmals belegt sind: die eines tribunus speculatorum und eines praefectus equitum et peditum, ausgeübt vermutlich zwischen der Einrichtung des Prinzipats und der Herrschaft des Claudius. Eine zweite Gruppe von sechs Texten bilden Monumente, die auf dem Forum der Kolonie gestanden haben müssen. Es handelt sich um zwei Inschriften zu Ehren örtlicher Honoratioren, einer Ehrung für einen neuen Prokonsul der Narbonensis namens Crassus, wahrscheinlich einen Auszug aus einem Ehrendekret, eine Inschrift, die an die Errichtung von zwei Statuen erinnert, und einen Text, in dem ein Dekret der Dekurionen erwähnt wird. Die Analyse erlaubt es, endgültig zu bestätigen, dass der Senator M. Pompeius Silvanus Staberius Flavenus aus Arles stammte, und seinen Namen zu präzisieren (Flavenus, nicht Flavinus). Abschliessend wird eine Gruppe von Texten präsentiert, die aus zwei Epitaphfragmenten und sieben weiteren, sehr kleinen Fragmenten besteht. Insgesamt bezeugen diese Inschriften die Vitalität des bürgerlichen Lebens in Arles und die frühe Existenz einer leistungsfähigen und loyalen Elite, die schon in den ersten Jahrzehnten der Geschichte der Kolonie in der Lage war, in die höheren Schichten der römischen Gesellschaft aufzusteigen.This article provides a detailled analysis of fragmentary inscriptions found as spolia in Arles. Most of them were found during the excavation of the cryptoporticos of the forum and had only been briefly announced so far. The first group sheds light on the military functions exercised by the equestrians of Arles at the beginning of the imperial period. After a discussion of three previously known documents, two texts are examined that mention hitherto unknown military posts: that of a tribunus speculatorum and of a praefectus equitum et peditum, presumably fulfilled between the beginning of the principate and the reign of Claudius. A second group consists of six texts which must have belonged to monuments that stood on the forum of the colony. These include two inscriptions in the honour of local notables, an homage to a new proconsul of Gallia Narbonensis named Crassus, presumably an extract from an honorary decree, an inscription that records the erection of two statues, and a text that mentions a decree of the decurions. The analysis makes it possible to establish with certainty that the senator M. Pompeius Silvanus Staberius Flavenus came from Arles and was in fact named Flavenus and not Flavinus. The last group presented is somewhat different and consists of two fragments of epitaphs and seven other, small fragments. The corpus attests to the vitality of civic life in Arles and the earlyexistence of a capable and loyal elite that was able to claim positions in the higher ranks of Roman society already in the first decades of the colony’s history.Cet article procède à l’étude détaillée de fragments d’inscriptions découverts à Arles, en remploi. La plupart d’entre eux proviennent des fouilles des cryptoportiques du forum et n’avaient été que brièvement signalés jusqu’alors. Un premier groupe met en lumière les commandements militaires reçus par des chevaliers arlésiens au début de l’époque impériale. Après l’évocation de trois documents déjà connus, sont étudiés deux textes mentionnant des fonctions militaires nouvellement attestées: celles de tribunus speculatorum et de praefectus equitum et peditum, sans doute remplies entre l’instauration du Principat et le règne de Claude. Un deuxième groupe de six textes est formé par des monuments qui devaient prendre place sur le forum de la colonie. Il s’agit de deux inscriptions en l’honneur de notables locaux, d’un hommage à un nouveau proconsul de Narbonnaise dénommé Crassus, d’un probable extrait de décret honorifique, d’une inscription commémorant l’érection de deux statues, et d’un texte mentionnant un décret des décurions. L’analyse permet d’établir définitivement l’origine arlésienne du sénateur M. Pompeius Silvanus Staberius Flavenus, et de mieux établir sa dénomination (Flavenus et non Flavinus). Un dernier groupe, d’une autre nature (deux fragments d’épitaphes et sept menus fragments), est enfin présenté. L’ensemble confirme la vitalité de la vie civique arlésienne et l’existence précoce d’une élite assez puissante et loyale pour accéder, dès les premières décennies de l’histoire de la colonie, aux ordres supérieurs de la société romaine

    Santé, soins, politiques sociales – SASOPO

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    Patrice Bourdelais, Didier Fassin, Georges Vigarello, directeurs d’étudesMaurice Cassier, Dominique Memmi, directeurs de recherche au CNRSOlivier Faure, professeur à l’Université Lyon-IIISerenella Nonnis Vigilante, maître de conférences à l’Université Paris-XIII, professeur à Politecnico de TurinRichard Rechtman, médecin-chef du CHS de La Verrière Retour sur les inégalités sociales de la santé Ce séminaire pluridisciplinaire s’est donné cette année pour objectif d’effectuer un retour sur les ..
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