Éditeur(s) : HAL CCSD
Résumé : International audience
The way faults control upward fluid flow in extensive hydrothermal systems without an abnormal heat source such as volcanic or plutonic activity is still unclear. In the Eastern Pyrénées, an alignment of 29 hot springs (from 29 • C to 73 • C) along the Têt normal Fault offers the opportunity to study this process. Using an integrated multi-scale geological approach including mapping, remote sensing, macro and microscopic analyses of fault zones, we show that hot springs locate close to high topographic reliefs related to fault throw and segmentation. Emergences are always in crystalline rocks at gneiss-metasediments contacts, mostly in the Têt Fault footwall. In more details, they localize either (1) in brittle fault damage zones at the intersection between the Têt Fault and subsidiary faults, and (2) into hercynian ductile faults where dissolution cavities run along shear zones. Using these observations and 2D preliminary numerical simulations, we propose a hydrogeological model of upward hydrothermal flow. Meteoric fluids infiltrate at high altitude in the fault footwall relief where they acquire temperature because of the geothermal gradient. Hydraulic gradient and buoyancy forces allow them to upflow along fault-related permeability anisotropies. The identification and prioritization of the features controlling this kind of system have important implications for geothermal exploration and for the understanding of fluid-flow into the brittle Earth's crust in general.
EGU 2017
Vienne, Austria

hal-01491096
https://hal-brgm.archives-ouvertes.fr/hal-01491096
https://hal-brgm.archives-ouvertes.fr/hal-01491096/document
https://hal-brgm.archives-ouvertes.fr/hal-01491096/file/EGU2017-Taillefer-etal_4996.pdf

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
IntroductionFever is associated with a poor outcome in severely brain-injured patients, and its control is one of the therapies used in this condition. But, fever suppression may promote infection, and severely brain-injured patients are frequently exposed to infectious diseases, particularly ventilator-associated pneumonia (VAP). Therefore, we designed a study to explore the role of a fever control protocol in VAP development during neuro-intensive care.MethodsAn observational study was performed on severely brain-injured patients hospitalized in a university ICU. The primary goal was to assess whether fever control was a risk factor for VAP in a prospective cohort in which a fever control protocol was applied and in a historical control group. Moreover, the density of VAP incidence was compared between the two groups. The statistical analysis was based on a competing risk model multivariate analysis.ResultsThe study included 189 brain-injured patients (intervention group, n¿=¿98, and historical control group, n¿=¿91). The use of a fever control protocol was an independent risk factor for VAP (hazard ratio 2.73, 95% confidence interval [1.38, 5.38; P¿=¿0.005]). There was a significant increase in the incidence of VAP in patients treated with a fever control protocol (26.1 versus 12.5 VAP cases per 1000 days of mechanical ventilation). In cases in which a fever control protocol was applied for >3 days, we observed a higher rate of VAP in comparison with the rate among patients treated for ¿3 days.ConclusionFever control in brain-injured patients was a major risk factor for VAP occurrence, particularly when applied for >3 days.
ISSN: 1364-8535

hal-01118640
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01118640
PUBMED : 25498970
DOI : 10.1186/s13054-014-0689-4
PUBMEDCENTRAL : PMC4279880

Éditeur(s) : HAL CCSD
Résumé : Visceral leishmaniasis is a life-threatening systemic disease caused by Leishmania protozoans, L. donovani and L. infantum, which invade mononuclear phagocytes in the lymphoid organs and the liver. The control of the hepatic parasite burden depends on the granuloma formation, which is favored by a Th1 immune response in a Th2 tissue microenvironment. The aim of this work was to study the role of the recently described Th2 cytokine IL-33 in this complex immune response, which remains partially misunderstood. IL-33 dosages in different patient sera and IL-33+ cells detected in the liver of a patient from Rennes suggested that IL-33 could be a biomarker for active visceral leishmaniasis. As IL-33 was described in hepatic stellate cells during chronic hepatitis, these cells were exposed to L. donovani in primary culture. The cell permissivity to L. donovani and the parasite persistence during a long term culture led us to propose hepatic stellate cells as a new type of sanctuary cells, which could partially explain asymptomatic carriage. However, these cells were apparently not the main source of IL-33 during visceral leishmaniasis. In infected BALB/c and C57BL/6 mice, IL-33 was detected in the liver in non stellate cells preferentially localized in granulomas. The presence of cells expressing its specific receptor ST2 in the liver led us to explore the role of the IL-33/ST2 axis. BALB/c mice deficient in ST2 or treated with recombinant IL-33 and infected with L. donovani revealed that IL-33 downregulates the expression of Th1 key cytokines (IL-12, IFN-γ) and the recruitment of neutrophils and monocytes. Finally, IL-33 acts as a susceptibility factor during visceral leishmaniasis. Besides, the model of L. donovani infected C57BL/6 mice deficient in IL-33 or treated with recombinant IL-33 suggests possible differential roles of IL-33 depending on the immune environment related to the host genetic background.
La leishmaniose viscérale est une maladie systémique mortelle en l’absence de traitement. Elle est due aux protozoaires Leishmania donovani et L. infantum, parasites des phagocytes mononucléés, capables d’envahir les organes lymphoïdes et le foie. Le contrôle de l’infection hépatique repose sur la mise en place d’une réponse granulomateuse efficace, promue par une réponse immunitaire Th1, dans un environnement tissulaire Th2. L’objectif de ce travail était l'étude du rôle d’une cytokine Th2 récemment décrite, l’IL-33, dans cette réponse hépatique complexe encore partiellement incomprise. Des dosages d’IL-33 sur des sérums de patients et la détection de cellules IL-33+ dans le foie d’un patient rennais ont placé l’IL-33 comme un biomarqueur possible de la maladie active. L’IL-33 étant exprimée dans les cellules étoilées du foie au cours d’hépatites chroniques, ces cellules ont été exposées à L. donovani. Leur permissivité aux leishmanies sans toxicité apparente ni perturbation de leurs propriétés fonctionnelles, ainsi que la persistance des leishmanies sur une culture de plusieurs semaines, nous ont conduit à proposer les cellules étoilées comme cellules sanctuaires possibles pour les leishmanies viscérotropes, contribuant donc potentiellement au portage asymptomatique. En revanche, elles ne sont pas apparues comme une source majeure d'IL-33 au cours de la leishmaniose viscérale. Chez des souris C57BL/6 et BALB/c infectées par L. donovani, l'IL-33 a été observée dans des cellules ne s'apparentant pas à des cellules étoilées, et principalement localisées dans les granulomes. Des cellules exprimant son récepteur ST2 ayant été également observées dans le foie, un rôle de l’axe IL-33/ST2 a été recherché. Les résultats obtenus chez des souris BALB/c déficientes en ST2 ou traitées par de l'IL-33 recombinante suggèrent que l'IL-33 régule négativement l'expression de cytokines Th1 (IL-12, IFN-γ) et l'infiltrat de neutrophiles et monocytes dans le foie, limitant ainsi le contrôle de la charge parasitaire. Ainsi, l'IL-33 semble être un facteur de susceptibilité pour la leishmaniose viscérale. En parallèle, des travaux entrepris sur des souris C57BL/6 infectées par L. donovani suggèrent de possibles rôles différentiels de l'IL-33 en fonction de l'environnement immunitaire inhérent au fond génétique de l'hôte.
https://tel.archives-ouvertes.fr/tel-01126847

Droits : info:eu-repo/semantics/OpenAccess
NNT : 2013REN1B002
tel-01126847
https://tel.archives-ouvertes.fr/tel-01126847
https://tel.archives-ouvertes.fr/tel-01126847/document
https://tel.archives-ouvertes.fr/tel-01126847/file/2013REN1B002.pdf

Éditeur(s) : HAL CCSD National Institute of Environmental Health Sciences
Résumé : International audience
Background: Glycol ethers (GE) are widely used organic solvents. Despite the potential neurotoxicity of several families of organic solvents, little is known about the impact of GE on the neurodevelopment of infants and children. Objectives: We investigated the relation between urinary concentrations of GE metabolites in pregnant women and neurocognitive abilities in their 6-year-old children in the PELAGIE mother-child cohort. Methods: Five GE metabolites were measured in first morning void urine samples of 204 French pregnant women in early pregnancy (<19 weeks of gestation). Psychologists assessed the neurocognitive abilities of their 6-year-old children with the Wechsler Intelligence Scale for Children IV (WISC) and the Developmental Neuropsychological Assessment (NEPSY). We analyzed the results with linear (WISC) and Poisson regression models (NEPSY), adjusted for potential confounders, including child's stimulation at home. Results: GE metabolites were detected in 90-100% of maternal urine samples. The WISC Verbal Comprehension score was significantly lower for children with the highest tertile of urinary phenoxyacetic acid (PhAA) [beta (third vs. first tertile)=-6.53; 95% CI: -11.44, -1.62]. Similarly, the NEPSY Design Copying subtest score was lower in those with the highest tertile of urinary ethoxyacetic acid (EAA) [beta (third vs. first tertile)=-0.11; 95% CI: -0.21, 0.00]. The other GE metabolites we studied were not significantly associated with WISC or NEPSY scores. Conclusions: Prenatal urine concentrations of two GE metabolites were associated with lower WISC Verbal Comprehension Index scores and NEPSY Design Copying subscale scores, respectively, at age 6 years. PhAA is the primary metabolite of 2-phenoxyethanol (EGPhE), which is commonly found in cosmetics, and precursors of EAA are frequently used in cleaning agents. Additional research is needed to confirm our findings and further explore potential effects of prenatal GE exposures on neurocognitive performance in children.
ISSN: 0091-6765

hal-01519256
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01519256
DOI : 10.1289/EHP39
PUBMED : 27740510

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The western margin of the Gulf of Mexico (Veracruz State, Mexico) displays an extensive Neogene gravitational system, whereby the Neogene siliciclastic sediments are detached from underlying Mesozoic carbonates along decollement surface in Oligocene underpressured clays. Rapidly subsiding half-grabens develop above the footwall associated with major listric faults, whereas mini-basins develop in the deepest parts of the slope, in conjunction with the growth of west-verging compressional features. Between the high-angle normal faults in the west and the thrust anticlines in the east, a wide roll-over structure has grown progressively, resulting in a major topographic break in the morphology of the slope profile. Coupled forward kinematic modelling (Thrustpack) and stratigraphic modelling (Dionisos), calibrated against seismic profiles and two key nearshore wells, have been applied to representative regional transects across the margin, in order to quantify the vertical (subsidence) and horizontal (gravitational) deformations, and to discuss the impact of various key parameters on the distribution of debris flow depositions. These simulations are compared with data from distant ODP wells and discussed in the scope of current exploration strategies in both the US and Mexican portions of the Gulf of Mexico basin.
ISSN: 0040-1951

hal-00424595
https://hal.archives-ouvertes.fr/hal-00424595
DOI : 10.1016/j.tecto.2008.06.017

Résumé : A travers diverses sources et particulièrement des sources orales recueillies auprès d’anciens militants communistes simples adhérents ou responsables et d’articles de la presse communiste martiniquaise, cette thèse cherche à éclairer sur la ferveur militante d’hommes et de femmes de la Martinique, d’une famille politique essentielle dans le courant du XXe siècle.Cette étude parcourt une longue période s’étendant principalement de 1920 à 1971, montrant les débuts balbutiants du communisme à la Martinique, son ascension, sa période florissante et les débuts de son lent déclin. La problématique est d’abord de faire découvrir des Martiniquais dans leur vécu de militant communiste, montrer comment ces hommes et ces femmes s’approprièrent une doctrine, la transformèrent peut-être pour l’adapter à leurs besoins, à leur culture. Il s’agit également d’examiner quelle structure communiste fut mise en place en Martinique, cette organisation était-elle à l’image des fédérations métropolitaines ou était-ce une formation politique spécifique au milieu martiniquais?Ensuite pour mieux appréhender les choix et les parcours, il a fallu arriver à l’identification des modèles, des origines de ce militantisme et la formation des militants. Les référents furent tant des figures propres au marxisme et au socialisme international et national que des personnalités contestataires du milieu politique martiniquais.Puis proposer une lecture des pratiques et des stratégies militantes pour évaluer la qualité et la particularité de cette militance ainsi que les conséquences de l’engagement de ces militants dans différentes sphères. Quelles étaient leurs propositions, pourquoi leurs revendications politiques différaient-elles de celles des autres communistes coloniaux ? Comment expliquer leurs choix d’une nouvelle société plus égalitaire dans un État socialiste mais toujours associé à la France ?Ce travail de recherches positionne cette militance au centre d’une analyse qui explore l’histoire politique et sociale d’une population, en s’appuyant sur d’autres disciplines comme la sociobiographie et les sciences politiques. Il examine le façonnement d’une société par un groupe politique prégnant entre 1920 et 1971, ainsi que les réponses de ce groupe face à différents problèmes politiques et sociaux en privilégiant une approche par les acteurs.
Through various sources, particularly oral sources collected from ancient communists, ordinary members or officials, and articles of martinican Communist press, this thesis shows about the militant fervor of martinican men and women and essential political family in the course of the twentieth century. This study covers a long period extending mainly from 1920 to 1971 showing the early stuttering of communism in Martinique, his ascension, his prosperous period and the beginning of his slow decline. The issue is first to make discover Martinicans in their experience of communist militant, present how these men and women appropriated a doctrine, transformed it perhaps to suit at their needs, at their culture. It is also to consider what communist structure was put in place in Martinique; this organization was it like the metropolitan federations or was it a specific political party? Then to better understand the choices and paths, it’s necessary arrive at identifying mentors, origins of this activism and training of militants. Referents were as figures specific to Marxism and international and national socialism as figures as specific martinican politics. Then offer a reading of practices and activist strategies for assessing the quality and uniqueness of this militancy and the consequences of the commitment of these activists in different spheres. What were their political choices, why their political demands did they differ from others colonial Communists? How to explain their choice of a new society more egalitarian in a socialist state, but always associated with France? This research study positions that militancy in the center of an analysis that explores the political and social history of a population, based on other disciplines such as socio-biography and political-sciences. It examines the shaping of a people by a political significant group between 1920 and 1971, and the proposals of this group face different political and social problems in promoting an approach by the actors.

http://www.theses.fr/2014AGUY0800

Éditeur(s) : HAL CCSD BioMed Central
Résumé : [b]Background[/b]: [i]Amblyomma variegatum[/i] and [i]A. hebraeum[/i] are two ticks of veterinary and human health importance in south-east Africa. In Zimbabwe they occupy parapatric (marginally overlapping and juxtaposed) distributions. Understanding the mechanisms behind this parapatry is essential for predicting the spatio-temporal dynamics of Amblyomma spp. and the impacts of associated diseases. It has been hypothesized that exclusive competition between these species results from competition at the levels of male signal reception (attraction-aggregation-attachment pheromones) or sexual competition for mates. This hypothesis predicts that the parapatry described in Zimbabwe could also be present in other countries in the region. [br/][b]Methods[/b]: To explore this competitive exclusion hypothesis we conducted field surveys at the two species' range limits in Mozambique to identify areas of sympatry (overlapping areas) and to study potential interactions (communicative and reproductive interference effects) in those areas. At sympatric sites, hetero-specific mating pairs were collected and inter-specific attractiveness/repellent effects acting at long and short distances were assessed by analyzing species co-occurrences on co-infested herds and co-infested hosts.[br/] [b]Results[/b]: Co-occurrences of both species at sampling sites were infrequent and localized in areas where both tick and host densities were low. At sympatric sites, high percentages of individuals of both species shared attachment sites on hosts and inter-specific mating rates were high. Although cross-mating rates were not significantly different for[i] A. variegatum[/i] and [i]A. hebraeum[/i] females, attraction towards hetero-specific males was greater for [i]A. hebraeum[/i] females than for A. variegatum females and we observed small asymmetrical repellent effects between males at attachment sites.[br/][b]Conclusions[/b]: Our observations suggest near-symmetrical reproductive interference between [i]A. variegatum[/i] and [i]A. hebraeum[/i], despite between-species differences in the strength of reproductive isolation barriers acting at the aggregation, fixation and partner contact levels. Theoretical models predict that sexual competition coupled with hybrid inviability, greatly reduces the probability of one species becoming established in an otherwise suitable location when the other species is already established. This mechanism can explain why the parapatric boundary in Mozambique has formed within an area of low tick densities and relatively infrequent host-mediated dispersal events.
ISSN: 1756-3305

hal-01220744
https://hal.archives-ouvertes.fr/hal-01220744
https://hal.archives-ouvertes.fr/hal-01220744/document
https://hal.archives-ouvertes.fr/hal-01220744/file/2015%20Bournez%20Parasites%20%26%20Vectors_%7B365AAFF5-7041-480B-9B77-9CD0485A9B72%7D.pdf
DOI : 10.1186/s13071-015-1116-7

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Background: Researchers sorely need markers and approaches for biodiversity exploration (both specimen linked and metagenomics) using the full potential of next generation sequencing technologies (NGST). Currently, most studies rely on expensive multiple tagging, PCR primer universality and/or the use of few markers, sometimes with insufficient variability. Methodology/Principal Findings: We propose a novel approach for the isolation and sequencing of a universal, useful and popular marker across distant, non-model metazoans: the complete mitochondrial genome. It relies on the properties of metazoan mitogenomes for enrichment, on careful choice of the organisms to multiplex, as well as on the wide collection of accumulated mitochondrial reference datasets for post-sequencing sorting and identification instead of individual tagging. Multiple divergent organisms can be sequenced simultaneously, and their complete mitogenome obtained at a very low cost. We provide in silico testing of dataset assembly for a selected set of example datasets. Conclusions/Significance: This approach generates large mitogenome datasets. These sequences are useful for phylogenetics, molecular identification and molecular ecology studies, and are compatible with all existing projects or available datasets based on mitochondrial sequences, such as the Barcode of Life project. Our method can yield sequences both from identified samples and metagenomic samples. The use of the same datasets for both kinds of studies makes for a powerful approach, especially since the datasets have a high variability even at species level, and would be a useful complement to the less variable 18S rDNA currently prevailing in metagenomic studies.
ISSN: 1932-6203

hal-01544766
https://hal.archives-ouvertes.fr/hal-01544766
DOI : 10.1371/journal.pone.0051263

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The tropical to warm-temperate marine brown macroalgal genus Lobophora (Dictyotales, Phaeophyceae) recently drew attention because of its striking regional diversity. In this study we reassess Lobophora global species diversity, and species distributions, and explore how historical factors have shaped current diversity patterns. We applied a series of algorithmic species delineation techniques on a global mitochondrial cox3 dataset of 598 specimens, resulting in an estimation of 98–121 species. This diversity by far exceeds traditional diversity estimates based on morphological data. A multi-locus time-calibrated species phylogeny using a relaxed molecular clock, along with DNA-confirmed species distribution data was used to analyse ancestral area distributions, dispersal-vicariance-founder events, and temporal patterns of diversification under different biogeographical models. The origin of Lobophora was estimated in the Upper Cretaceous (−75 to −60 MY), followed by gradual diversification until present. While most speciation events were inferred within marine realms, founder events also played a non-negligible role in Lobophora diversification. The Central Indo-Pacific showed the highest species diversity as a result of higher speciation events in this region. Most Lobophora species have small ranges limited to marine realms. Lobophora probably originated in the Tethys Sea and dispersed repeatedly in the Atlantic (including the Gulf of Mexico) and Pacific Oceans. The formation of the major historical marine barriers (Terminal Tethyan event, Isthmus of Panama, Benguela upwelling) did not act as important vicariance events. Long-distance dispersal presumably represented an important mode of speciation over evolutionary time-scales. The limited geographical ranges of most Lobophora species, however, vouch for the rarity of such events.
ISSN: 1055-7903

hal-01535635
http://hal.upmc.fr/hal-01535635
http://hal.upmc.fr/hal-01535635/document
http://hal.upmc.fr/hal-01535635/file/Vieira_2017_Historical.pdf
DOI : 10.1016/j.ympev.2017.03.007

Éditeur(s) : Elsevier
Résumé : The discovery of deep-sea hydrothermal vent fauna, kilometres deep in the oceans, is a great achievement of 20th-century marine biology. The deep-sea hydrothermal food web does not directly depend on the sun's energy. Vent communities rely primarily on trophic associations between chemoautotrophic bacteria and consumers A small. number of endemic taxa are adapted to the inhospitable vent environments that are distributed along ridge crests. Where these vent communities originated and how they dispersed are among the important questions ecologists must answer. Here, by statistical analysis of the most comprehensive database ever assembled about deep-sea hydrothermal fauna, we delineate six major hydrothermal provinces in the world ocean and identify seven possible dispersal pathways between adjacent provinces. Our model suggests that the East-Pacific Rise may have played a pivotal role as a centre of dispersal for the hydrothermal fauna. Our data-driven conclusion will have to be tested by phylogenetic studies and completed by surveys of less-explored fields.
Deep Sea Research Part I: Oceanographic Research Papers (0967-0637) (Elsevier), 2009-08 , Vol. 56 , N. 8 , P. 1371-1378

Droits : 2009 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/2009/publication-6936.pdf
http://archimer.ifremer.fr/doc/2009/sup-6936.xls
DOI:10.1016/j.dsr.2009.01.009
http://archimer.ifremer.fr/doc/00000/6936/