Éditeur(s) : HAL CCSD
Résumé : International audience
The purpose of our study is to model a geothermal reservoir. When geothermal reservoir are assumed to be composed of pure water, the transfer of mass and energy is classically described by two balance equations: mass balance equation and the energy balance equation. In addition to those equations, fluid velocity ist classically given by the Darcy law while thermodynamic properties, inferred from theoretical or empirical equations of state, are used to close the mathematical system. Once this system is closed, there exist different solutions. The first one is to solve for pressure and temperature with a variable switch to saturation in the two-phase region (e.g. TOUGH2). The second one is to solve for pressure and enthalpy to increase stability of phase transition between single and two-phase states (e.g. Hydrotherm). We adopted the second option and chose te use a splitting method to get rid of the complexity of coupling equations and a finite volume method for the spatial discretization. Selecting object-oriented languages, we developed a multi-language framework, combining Python, Fortran and a C++ implementation of IAPWS (from the freesteam project) including the supercritical equations, in porous media velocity is given by Darcy law and to close the system physical properties are determined by the IAPWS-IF97 thermodynamic formulation. We resolve the equations in pressure and enthalpy instead of pressure and temperature in order to increase stability and to handle easier the passage from a single-phase to a two-phase system. We solve the system by using a splitting method - to get rid of the complexity of coupling equations - and a finite volume method. We offer some freedom to users thanks to the implementation of several methods like explicit or implicit Euler, Runge-Kutta or BDF2 for time solvers or GMRES and BICGSTAB for the linear solver. We can handle several boundary conditions like no-flow - describing a boundary which can not exchange matter with the exterior - or like a mixed-therm condition - a Dirichlet condition to the pressure and a Dirichlet or an outflow condition to the temperature in order to describe a recharge or a discharge zone - ... We're developing a multi-language framework, combining Python, Fortran and the C++ implementation of IAPWS (from the freesteam project). All these languages are object-oriented. We've applied this simulation model to the dogger in Paris, France, to several one-dimensional systems and a two-dimensional one made by Coumou with the CSMP++ platform. The dogger is a reservoir exploited to produce heat by pumping water at 70 and reinjecting it in the reservoir at 40. In the one-dimensional systems we wanted to observe the process of heat transfer from a higher temperature boundary to a smaller one in a high-energy domain. The last simulation shows the natural convection of water in a fault. For every simulation we compared the solutions we found with an other code (TOUGH2 or CSMP++) and they agreed. The next step will be to model the geothermal plant in Guadeloupe, West Indies. It's the only place in France - and in the West Indies so far - producing electricity with the earth power. The temperature can reach up to 1000 and the pressure range is around a few hundreds MPa. In some surface zones we can see two-phase water at atmospheric pressure. In the 1980s Bouillante was a laboratory for France. Since 1995 Bouillante has given 30GWh electricity a year to the Guadeloupeans.
PROCEEDINGS, Thirty-Ninth Workshop on Geothermal Reservoir Engineering
Stanford, United States

Droits : info:eu-repo/semantics/OpenAccess
hal-00944133
https://hal-brgm.archives-ouvertes.fr/hal-00944133
https://hal-brgm.archives-ouvertes.fr/hal-00944133/document
https://hal-brgm.archives-ouvertes.fr/hal-00944133/file/Copol.pdf

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The purpose of this investigation was to characterize the management and prognosis of severe Pneumocystis jirovecii pneumonia (PJP) in human immunodeficiency virus (HIV)-negative patients. An observational cohort study of HIV-negative adults with PJP documented by bronchoalveolar lavage (BAL) through Gomori-Grocott staining or immunofluorescence, admitted to one intensive care unit (ICU) for acute respiratory failure, was undertaken. From 1990 to 2010, 70 patients (24 females, 46 males) were included, with a mean age of 58.6 ± 18.3 years. The mean Simplified Acute Physiology Score (SAPS)-II was 36.9 ± 20.4. Underlying conditions included hematologic malignancies (n = 21), vasculitis (n = 13), and solid tumors (n = 13). Most patients were receiving systemic corticosteroids (n = 63) and cytotoxic drugs (n = 51). Not a single patient received trimethoprim-sulfamethoxazole as PJP prophylaxis. Endotracheal intubation (ETI) was required in 42 patients (60.0 %), including 38 with acute respiratory distress syndrome (ARDS). In-ICU mortality was 52.9 % overall, reaching 80.9 % and 86.8 %, respectively, for patients who required ETI and for patients with ARDS. In the univariate analysis, in-ICU mortality was associated with SAPS-II (p = 0.0131), ARDS (p < 0.0001), shock (p < 0.0001), and herpes simplex virus (HSV) or cytomegalovirus (CMV) on BAL (p = 0.0031). In the multivariate analysis, only ARDS was associated with in-ICU mortality (odds ratio [OR] 23.4 [4.5-121.9], p < 0.0001). PJP in non-HIV patients remains a serious disease with high in-hospital mortality. Pulmonary co-infection with HSV or CMV may contribute to fatal outcome.
ISSN: 0934-9723

inserm-00872789
http://www.hal.inserm.fr/inserm-00872789
DOI : 10.1007/s10096-012-1730-7
PUBMED : 22930407

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
This study reports petrostructural observations in the pargasite and phlogopite-bearing Finero peridotite massif (Italian Western Alps), which suggest that the pervasive foliation in this massif was formed by deformation concomitant with percolation of hydrous Si-rich melts: (1) diffuse contacts, but systematic parallelism between the pyroxenitic layers and the foliation of the peridotite (2) strong shape and crystal preferred orientations (SPO and CPO), but subhedral or interstitial shapes and weak intracrystalline deformation of the hydrous phases, (3) CPO, but interstitial shapes of the pyroxenes, (4) very coarse olivine grain sizes, which are correlated to the olivine abundance, and (5) elongated shapes, but weak intracrystalline deformation, and extremely weak and highly variable CPO of olivine. The pervasive deformation of the Finero peridotite occurred therefore under conditions that allowed coexistence of H2O–CO2-bearing melts, pargasite, and spinel, that is, temperatures of 980–1080 °C and pressures <2 GPa. The petrostructural observations suggest that the presence of hydrous melts results in accommodation of large amounts of deformation by stress-controlled dissolution–precipitation and advective transport of matter by the melts and in fast grain boundary migration in olivine. By consequence, it produces significant rheological weakening. Water contents in olivine are <4 ppm wt., implying limited contribution of hydration of olivine to weakening. In addition, the analysis of protomylonites composing the external domains of the shear zones that overprint the pervasive foliation indicates that the transition to melt-free conditions results in enhanced contribution of dislocation creep to the deformation. The associated increase of the peridotites' strength leads to onset of strain localization. The latter is not correlated to the local abundance in pargasite or phlogopite, implying that crystallization of amphiboles or phlogopite, even at concentrations of 25 vol.%, does not produce rheological weakening in the upper mantle.
ISSN: 0012-821X

hal-01667879
https://hal.archives-ouvertes.fr/hal-01667879
DOI : 10.1016/j.epsl.2017.08.015

Éditeur(s) : HAL CCSD SAGE Publications
Résumé : International audience
The distribution of redox-sensitive elements (V, U, Mo, Mn) was studied in a sedimentary archive of the Pierre-Blanche lagoon encompassing 3500 years of sedimentation. Between 240 and 255 cm (i.e. between 0 and 350 cal. ad) in the core, there was a dark layer with no mollusc shells. Enrichments of V, U and Mo and depletion of Mn were observed in this layer compared with overlying and underlying sediments. This was attributed to the occurrence of anoxia in bottom water or at the sediment/water interface during the Roman period. This episode was concomitant with the formation of a sandy barrier, which now isolates the lagoon from the sea. Our results suggest that the isolation of the lagoon, which was deeper in the period concerned than at present, favoured stagnation of the water. Combined with the excess nutrient inputs because of human activities in Lattara harbour, stagnation may have caused anoxia in bottom water at least in some parts of the Palavasian lagoon system. Bottom conditions nevertheless remained sufficiently reducing for the accumulation of U and Mo to persist until around 800 cal. ad. Although the lagoon has been hyper-eutrophic since at least the middle of the 20th century and although anoxia occurs frequently in summer, redox proxies show no evidence for their occurrence. The shallow water and associated resuspension and reoxidation events explain the lack of V, Mo and U enrichment in recent sediments.
ISSN: 0959-6836

hal-01062151
https://hal.archives-ouvertes.fr/hal-01062151

Éditeur(s) : HAL CCSD
Résumé : Water vapour is highly variable in the atmosphere with concentration reaching saturation in the tropics and with dry areas over elevated continental region. Good knowledge of the amount of integrated water vapour in the air is necessary to predict phase changes and in particular precipitation. Water vapour variability measurements are still insufficient with standard observing systems. Moreover accurate GPS antenna positioning is affected by the refractivity index variation in the troposphere. Consequently, vertical positioning component estimation is difficult. This variation is directly linked to distribution of variables such as pressure, temperature and humidity along the path between satellite and receiver. Here we study more specifically heavy rains et notably Cevenols events. This thesis work consists to check the GPS measurement validity to quantify water vapour in comparison with measurements from radiosoundings and meteorological model outputs. GPS observations and flux surface information have been analysed to see if water vapour quantification by GPS allowed characterising heavy rain events (cumulative rainfall amount greater than 150 mm). Then, we tested the GPS data assimilation impact on cumulative precipitation forecasts using the high resolution Meteo France AROME model (2.5 km). Finally the quality and the contribution of GPS measurement on sea is evaluated for water vapour measurement. This study has been realised in the framework of VAPIMED experiment.
La vapeur d'eau varie largement dans l'atmosphère avec des concentrations allant de la saturation dans les tropiques à des zones presque sèches au-dessus des zones continentales élevées. Une bonne connaissance du contenu en vapeur d'eau dans l'air est nécessaire pour la prévision des changements de phases, notamment les précipitations. La mesure de la variabilité de la vapeur d'eau est une lacune des systèmes d'observation. Par ailleurs, il est apparu que le positionnement précis des antennes GPS était affecté par la variation de l'indice de réfraction dans la troposphère, ce qui rend particulièrement difficile l'estimation de la composante verticale. Cette variation est directement liée à la distribution des variables pression, température et humidité sur les trajets satellite-récepteur. On s'intéresse ici à l'étude des précipitations intenses et notamment aux épisodes Cévenols. Ce travail de thèse consiste à vérifier la validité de la mesure GPS pour la quantification de la vapeur d'eau en la comparant avec des mesures issues de radiosondage et des sorties de modèle météorologique. On cherche à analyser si la quantification de vapeur d'eau par GPS permet de caractériser les forts événements précipitants (cumuls supérieurs à 150 mm) à l'aide d'observations conjointes sur les flux de surface. On étudie ensuite l'impact de l'assimilation de données GPS issues d'un réseau GPS dense sur la prévision des cumuls de pluies dans le modèle à hauterésolution (2.5 km) AROME de Météo France. Finalement on évalue la qualité et l'apport de la mesure de vapeur d'eau par GPS en mer dans le cadre d'une campagne de mesure VAPIMED).
https://tel.archives-ouvertes.fr/tel-00444081

Droits : info:eu-repo/semantics/OpenAccess
tel-00444081
https://tel.archives-ouvertes.fr/tel-00444081
https://tel.archives-ouvertes.fr/tel-00444081/document
https://tel.archives-ouvertes.fr/tel-00444081/file/These_KBoniface.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Gulf of Cadiz spans the plate boundary between Africa and Eurasia west of the Betic–Rif mountain belt. A narrow east dipping subduction zone descends beneath the Gulf of Cadiz and the straits of Gibraltar. The deep crustal structure of the Gulf and the adjacent SW Iberian and Moroccan margins is constrained by numerous multi-channel seismic reflection and wide-angle seismic surveys. A compilation of these existing studies is presented in the form of depth to basement, sediment thickness, depth to Moho and crustal thickness maps. These structural maps image an E–W trending trough, with thin (< 10 km) crust beneath the Gulf of Cadiz. This trough is filled by an eastward thickening wedge of sediments, reaching a thickness of 10–15 km in the eastern Gulf. These sediments are tectonically deformed, primarily along a series of westward-vergent thrust faults and represent a 200–250 km wide accretionary wedge. The northern and especially the southern limits of the accretionary wedge are marked by sharp morphological lineaments showing evidence of recent deformation. These tectonic limits are situated in an internal position with respect to the Miocene deformation front (external Betic and Rif allocthons), which has been abandoned. At the western boundary of the accretionary wedge, near the adjacent Seine and Horseshoe abyssal plains, an E–W trending basement high (Coral Patch Ridge) can be seen indenting the deformation front in an asymmetric manner. Analog modeling is performed using granular materials accreted against a semicircular backstop (representing the basement of the Rif and Betic mountain belts). The modeling initially produces a symmetric, arcuate accretionary wedge. The ensuing collision of an oblique rigid indenter retards accretion on one side, resulting in an embayment and a locally steeper deformation front. The deformation pattern observed in morphology and high-resolution seismic profiles suggests the accretionary wedge and underlying subduction system is still active. The implications of active subduction for the source region of the 1755 Lisbon earthquake and the regional seismic hazard assessment are discussed.
ISSN: 0040-1951

hal-00424922
http://hal.univ-brest.fr/hal-00424922
http://hal.univ-brest.fr/hal-00424922/document
http://hal.univ-brest.fr/hal-00424922/file/Gutscher_09Tphys_rev.pdf
DOI : 10.1016/j.tecto.2008.11.031

Éditeur(s) : Copernicus Gesellschaft Mbh
Résumé : During the GWADASEIS cruise (Lesser Antilles volcanic arc, February-March 2009) a very high resolution (VHR) seismic-reflection survey was performed in order to constrain Late Quaternary to Present faulting. The profiles we obtained evidence frequent "ponding" of reworked sediments in the deepest areas, similar to the deposition of Mediterranean "homogenites". These bodies are acoustically transparent (few ms t.w.t. thick) and are often deposited on the hanging walls of dominantly normal faults, at the base of scarps. Their thickness appears sufficient to compensate (i.e. bury) co-seismic scarps between successive earthquakes, resulting in a flat and horizontal sea floor through time. In a selected area (offshore Montserrat and Nevis islands), piston coring (4 to 7m long) was dedicated to a sedimentological analysis of the most recent of these particular layers. It corresponds to non-stratified homogenous calcareous silty sand (reworked calcareous plankton and minor volcanoclastics). This layer can be up to 2 m thick, and overlies fine-grained hemipelagites. The upper centimeters of the latter represent the normal RedOx water/sediment interface. Pb-210 and Cs-137 activities lack in the massive sands, while a normal profile of unsupported Pb-210 decrease is observed in the hemipelagite below, together with a Cs-137 peak corresponding to the Atmospheric Nuclear Experiments (1962). The RedOx level was thus capped by a recent instantaneous major sedimentary event considered as post-1970 AD; candidate seismic events to explain this sedimentary deposits are either the 16 March 1985 earthquake or the 8 October 1974 one (M-w = 6.3 and M-w = 7.4, respectively). This leads to consider that the syntectonic sedimentation in this area is not continuous but results from accumulation of thick homogenites deposited after the earthquakes (as observed in the following weeks after Haiti January 2010 event, McHugh et al., 2011). The existence of such deposits suggests that, in the area of study, vertical throw likely results from cumulated effects of separated earthquakes rather than from aseismic creep. Examination of VHR profiles shows that all major co-seismic offsets are recorded in the fault growth sequence and that co-seismic offsets can be precisely estimated. By using a sedimentation rate deduced from Pb-210 decrease curve (0.5 mmyr(-1)) and taking into account minor reworking events detected in cores, we show that the Redonda system may have been responsible for five > M-6 events during the last 34 000 yr. The approach presented in this work differs from fault activity analyses using displaced sets of isochronous surfaces and postulating co-seismic offsets. Combining VHR seismic imagery and coring we can decipher co-seismic vs. slow continuous displacement, and thus actually estimate the amplitude and the time distribution of major co-seismic offsets.
Natural Hazards And Earth System Sciences (1561-8633) (Copernicus Gesellschaft Mbh), 2012 , Vol. 12 , N. 5 , P. 1755-1767

Droits : Author(s) 2012. CC Attribution 3.0 License.
http://archimer.ifremer.fr/doc/00089/20040/21990.pdf
DOI:10.5194/nhess-12-1755-2012
http://archimer.ifremer.fr/doc/00089/20040/

Éditeur(s) : Université de Bretagne Occidentale
Résumé : Study of mineral suspended particulate matter (SPM) is essential to understand ecosystem dynamics. SPM influences light penetration which is closely related to primary production and carries pollutants and nutrients within the water masses. This work aims to study near-surface mineral SPM dynamics in the English Channel using two complementary methods: remote-sensing by satellites and numerical modelling. Firstly, MODIS and MERIS satellite images processed by the IFREMER semi-analytical algorithm and describing non-algal SPM, are analysed to build three statistical models which are able to estimate near-surface SPM using simple variables, e.g., tidal coefficient, significant wave height and mean chlorophyll-a concentration. Secondly, the three-dimensional hydrosedimentary model ROMS (Regional Ocean Modeling System) is applied in the English Channel. It considers tidal forcing along open boundaries, wind stress at the sea-surface, wave-current interactions in the bottom boundary layer and realistic heterogeneous bottom sediments. Results of the more sophisticated statistical model is also used to impose SPM concentrations at open boundaries. Sensitivity tests on SPM boundary conditions show the importance of prescribing realistic sediment concentrations to improve the model predictions. Biological influences on mineral SPM are also tested using settling velocity and critical shear stress for erosion which vary with seasons. Both statistical and numerical models highlight and locate respective influences of tide, waves and biology on mineral SPM. Numerical predictions indicate that near-surface SPM is mainly composed of silts (>70%). Near-surface suspended silts come largely from seabed resuspension alongshore in the Eastern Channel and from the open boundaries of our limited-area coastal model at the West of Cotentin Peninsula and offshore. Near-surface SPM variations are investigated at semi-diurnal, neap-spring tidal cycle time scales and during a wave event. Finally, dynamics of sediments in the turbidity maximum zone around the Isle of Wight is examined depending on hydrodynamical conditions in order to distinguish the role played by advection and local erosion/settling processes in this area. Keywords: Suspended particulate matter, satellite, remote-sensing, modelling, English Channel, sediments, turbidity, tide, wave
L'étude des matières en suspension (MES) minérales est essentielle pour comprendre le fonctionnement des écosystèmes en Manche : les MES influencent la pénétration de la lumière dans la colonne d'eau, paramètre clé pour la production biologique, et sont susceptibles de transporter des polluants et nutriments. Lors de ce travail, la dynamique des MES minérales de surface en Manche est étudiée à l'aide de deux méthodes complémentaires : l'observation par satellite et la modélisation numérique tridimensionnelle. Dans un premier temps, les images satellite MODIS et MERIS, traitées par l'algorithme semi-analytique développé par l'IFREMER et représentant les MES non-algales de surface, sont analysées afin d'élaborer trois modèles statistiques permettant d'estimer la MES de surface en fonction de variables basiques telles que le coefficient de marée, la hauteur significative des vagues et la concentration moyenne en chlorophylle-a. Dans un deuxième temps, le modèle hydrosédimentaire multiclasse tridimensionnel ROMS (Regional Ocean Modeling System) est implémenté en Manche. Il prend en considération le forçage par la marée aux frontières ouvertes, la contrainte exercée par le vent à la surface de la mer, l'interaction houle-courant en couche limite de fond et l’hétérogénéité spatiale réaliste du lit sédimentaire. Les résultats du modèle statistique le plus sophistiqué sont également utilisés pour forcer la concentration en MES aux frontières ouvertes du domaine de calcul. Des tests de sensibilité sur les conditions limites montrent l'importance de considérer de manière réaliste les sédiments entrant en Manche par les frontières ouvertes lors de la modélisation numérique. L'influence de la biologie sur les MES minérales est testée en utilisant une formulation de la vitesse de chute et de la contrainte critique d'érosion variant saisonnièrement. Grâce à ces deux outils associés, les influences respectives de la marée, de la houle et de la biologie sur les MES minérales sont mises en avant et localisées en Manche. Le modèle numérique prédit que les MES de surface sont composées principalement de silts (>70%). Les silts en suspension en surface proviennent majoritairement du lit sédimentaire près des côtes en Manche orientale et des frontières ouvertes du domaine de calcul à l'ouest de la presqu'île du Cotentin et au large en Manche centrale et orientale. Les variations des MES de surface sont ensuite étudiées aux échelles des cycles de marée semi-diurnes, vive-eau/morte-eau et autour d'un épisode de houles. Enfin, l'évolution de la concentration de sédiments dans la zone de forte turbidité autour de l'île de Wight peut être analysée suivant les conditions hydrodynamiques afin d'évaluer les rôles respectifs des processus locaux d'érosion/dépot et d'advection dans la génération de ces turbidités remarquables. Mots-clés : Matière en suspension, télédétection, satellite, modélisation, Manche, sédiments, turbidité, marée, houle

Droits : 2013 UBO
http://archimer.ifremer.fr/doc/00157/26783/24884.pdf
http://archimer.ifremer.fr/doc/00157/26783/

Éditeur(s) : HAL CCSD
Résumé : Background. Chlorine is the most widely used disinfectant for drinking water treatment. During treatment process, the natural organic matter present in water reacts with chlorine to form disinfection by-products (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs), the most occurring ones. Several identified DBPs were recognized carcinogens or fetotoxic in animals. We conducted two epidemiological studies to assess the health effects of human exposure to DBPs regarding cancer and reproduction. Association between THM exposure and the risk of bladder cancer: a pooled analysis of 3 European case-control studies. The study included 2381 cases and 3086 controls from 3 case-control studies (France, Finland, Spain). Environmental exposure to SPCs was measured by THM concentrations in water distribution systems, retrospectively estimated through the 40-year exposure window. Information about water uses (tap water ingestion, showers and baths, swimming-pool attendance) was available. An increased risk of bladder cancer was observed, in men only, with increasing THM concentrations in water systems and duration of exposure to chlorinated surface water. No association was observed with exposure through tap water ingestion. Exposure through showers, baths and swimming in pools (available in Spanish study only) was associated with an increased risk of bladder cancer. Three North-American case-control studies were joined to the three European ones into a meta-regression. No specific dose-response relationship was identified for European studies. A global dose-response relationship was consequently estimated, including 4351 cases and 7055 controls. Association between DBP exposure and the risk of preterm birth and Intra-Uterine Growth Retardation (IUGR). This study was conducted within the PELAGIE cohort (3400 pregnant women included in early pregnancy, in Brittany, France, between 2002 and 2006). Exposure during pregnancy was measured by 2 indicators: THM concentrations in water distribution systems and a biomarker of HAA ingestion, the level of trichloroacetic acid in maternal urine at inclusion (in a nested case-control study). The regulatory database SISE-Eaux was used to estimate THMs concentrations in the water distribution systems. Water uses during pregnancy (ingested tap water, swimming-pool attendance, showers and bath frequencies and duration) were collected with questionnaires. Our results suggest an association between prenatal exposure to DBPs (THMs and HAAs) and the risk of IUGR. No association was found with the risk of preterm birth.
Contexte. La chloration est le traitement le plus utilisé pour désinfecter l’eau distribuée à la population. Lors du traitement, des sous-produits de chloration (SPCs) se forment par réaction de la matière organique naturelle présente dans l’eau avec le chlore. Les produits les plus présents sont les trihalométhanes (THMs), les acides haloacétiques (HAAs). Des études toxicologiques (animales et in vitro) ont montré la génotoxicité et/ou carcinogénicité et la reprotoxicité de certains SPCs. Nous avons mené deux études évaluant les effets sur la santé humaine de l’exposition aux SPCs, dans le domaine du cancer et de la reproduction. Association entre exposition aux THMs et risque de cancer de la vessie : une analyse poolée de 3 études cas-témoins européennes. Cette analyse a inclus 2381 cas et 3086 témoins issus de 3 études cas-témoins (France, Espagne, Finlande). L’exposition environnementale aux SPCs a été mesurée par la concentration en THMs estimée rétrospectivement dans les réseaux de distribution d’eau au cours des 40 années de la fenêtre d’exposition. Les usages de l’eau connus sont l’ingestion, les douches et les bains, la fréquentation de piscine (étude espagnole seulement). Une relation croissante a été observée entre le niveau environnemental de THMs, la durée d’exposition à une eau de surface chlorée et le risque de cancer de la vessie, chez les hommes uniquement. Aucune association n’a été observée avec l’exposition via l’ingestion d’eau du robinet. L’exposition via les douches, les bains et la piscine est apparue liée au risque de cancer de la vessie. Trois études cas-témoins nord-américaines ont été intégrées dans une méta-régression. Aucune spécificité européenne de la relation dose-réponse n’a été mise en évidence. Une relation dose-réponse globale incluant 4351 cas et 7055 témoins a été estimée. Association entre exposition aux SPCs et risque de prématurité et de retard de croissance intra-utérin (RCIU). Cette étude est issue de la cohorte bretonne Pélagie (3400 femmes enceintes recrutées en début de grossesse entre 2002 et 2006). L’exposition pendant la grossesse a été mesurée à l’aide de 2 indicateurs : la concentration en THMs de l’eau distribuée dans les réseaux et le dosage d’un biomarqueur urinaire (acide trichloroacétique) pour un sous-échantillon de femmes (étude cas-témoins nichée). Les niveaux dans les réseaux proviennent de la base de données réglementaire SISE-Eaux. Les usages de l’eau du robinet par les femmes pendant la grossesse ont été collectés par questionnaire (quantité d’eau du robinet bue, fréquentation de la piscine, fréquence et durée des douches et des bains). Notre étude suggère une association entre l’exposition prénatale aux SPCs et le risque de RCIU. Aucune association n’est observée avec le risque de prématurité.
https://tel.archives-ouvertes.fr/tel-00927735

Droits : info:eu-repo/semantics/OpenAccess
NNT : 2013REN1B008
tel-00927735
https://tel.archives-ouvertes.fr/tel-00927735
https://tel.archives-ouvertes.fr/tel-00927735/document
https://tel.archives-ouvertes.fr/tel-00927735/file/COSTET_DEIBER_Nathalie4.pdf

Éditeur(s) : Elsevier Science Bv
Résumé : Recent advances in technologies have lead to a vast influx of data on movements, based on discrete recorded position of animals or fishing boats, opening new horizons for future analyses. However, most of the potential interest of tracking data depends on the ability to develop suitable modelling strategies to analyze trajectories from discrete recorded positions. A serious modelling challenge is to infer the evolution of the true position and the associated spatio-temporal distribution of behavioural states using discrete, error-prone and incomplete observations. In this paper, a Bayesian Hierarchical Model (HBM) using Hidden Markov Process (HMP) is proposed as a template for analyzing fishing boats trajectories based on data available from satellite-based vessel monitoring systems (VMS). The analysis seeks to enhance the definition of the fishing pressure exerted on fish stocks, by discriminating between the different behavioural states of a fishing trip, and also by quantifying the relative importance of each of these states during a fishing trip. The HBM approach is tested to analyse the behaviour of pelagic trawlers in the Bay of Biscay. A hidden Markov chain with a regular discrete time step is used to model transitions between successive behavioural states (e.g., fishing, steaming, stopping (at Port or at sea)) of each vessel. The parameters of the movement process (speed and turning angles) are defined conditionally upon the behavioural states. Bayesian methods are used to integrate the available data (typically VMS position recorded at discrete time) and to draw inferences on any unknown parameters of the model. The model is first tested on simulated data with different parameters structures. Results provide insights on the potential of HBM with HMP to analyze VMS data. They show that if VMS positions are recorded synchronously with the instants at which the process switch from one behavioural state to another, the estimation method provides unbiased and precise inferences on behavioural states and on associated movement parameters. However, if the observations are not gathered with a sufficiently high frequency, the performance of the estimation method could be drastically impacted when the discrete observations are not synchronous with the switching instants. The model is then applied to real pathways to estimate variables of interest such as the number of operations per trip, time and distance spent fishing or travelling. (C) 2010 Elsevier B.V. All rights reserved.
Ecological Modelling (0304-3800) (Elsevier Science Bv), 2010-07 , Vol. 221 , N. 15 , P. 1757-1769

Droits : 2010 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00009/11993/9342.pdf
DOI:10.1016/j.ecolmodel.2010.04.005
http://archimer.ifremer.fr/doc/00009/11993/

Éditeur(s) : HAL CCSD Editions Paralia CFL
Résumé : Le lido de Villeneuve-lès-Maguelone (Languedoc-Roussillon) est un archétype de littoral microtidal, dominé par la houle, en érosion, et largement affecté par la submersion marine lors des tempêtes. Les observations réalisées dans le cadre du Système d'Observation Littoral - Trait de Côte (SO LTC) concernent l'hydrodynamique et le transport sédimentaire dans l'avant-côte et la lagune. La tache d'observation MAGOBS (Observatoire Aresquiers-Maguelone-Palavas) de cet observatoire regroupe un dispositif instrumental automatisé composé de 30 points d'acquisition en temps réel entre 6 mètres de profondeur et le haut de plage (à terre) ainsi que dans la lagune. Le dispositif est opérationnel depuis mai 2011. Son déploiement a permis de déverrouiller les difficultés techniques liées à la mesure temps réel en zone littorale : choix du type des appareils de mesure, de la technologie embarquée, des cadences d'acquisition, résolution des questions du transfert de la donnée. Le dispositif produit 2 Tera-octets de données par an. Les données sont stockées sur un ensemble de serveurs dédiés. Les données sont mises en ligne sur le site du SO-LTC (www.soltc.org), immédiatement après premiers traitements et qualification. Elles commencent à être utilisées pour des calculs de niveau d'eau à la côte, et dansdes outils de prédiction des vagues et des niveaux à la côte associant mesure et modélisation.
ISSN: 1760-8716

hal-00854410
https://hal.archives-ouvertes.fr/hal-00854410
DOI : 10.5150/jngcgc.2012.064-G

Éditeur(s) : Amer Geophysical Union
Résumé : The temporal evolution and spatial distribution of surface salinity and colored detrital matter (cdm) were evaluated within and adjacent to the Amazon River Plume. Study objectives were as follows: first, to document the spatial coherence between Amazon discharge, salinity, cdm, and the nature of the salinity-cdm relationship; second, to document the temporal and spatial variability of cdm along the trajectory of the low-salinity Amazon Plume, and third, to explore the departure of cdm from conservative mixing behavior along the plume trajectory into the open ocean. Time series (2003-2007) of surface salinity estimated using the Advanced Microwave Scanning Radiometer-Earth Observing System and corresponding satellite cdm absorption (acdm) data documented a plume of freshened, colored water emanating from the Amazon. Salinity and acdm were generally coherent, but there were regions in which spatial patterns of salinity and acdm did not coincide. Salinity was oppositely phased with discharge, whereas acdm was in phase but lagged discharge and typically remained high after maximum discharge. Along the river plume trajectory, acdm was inversely correlated with salinity, yet there was considerable deviation from conservative mixing behavior during all seasons. Positive anomalies in a linear relationship between salinity and acdm corresponded to areas of enhanced satellite-retrieved net primary productivity, suggesting the importance of phytoplankton biomass or its subsequent remineralization as a source of cdm. Negative anomalies tended to predominate at the distal sections of the plume trajectories, an observation consistent with the process of photo-oxidation of cdm over observed time scales of days to weeks.
Journal Of Geophysical Research-oceans (0148-0227) (Amer Geophysical Union), 2011-07 , Vol. 116 , N. C00H02 , P. 14 p.

Droits : 2011 American Geophysical Union. All Rights Reserved.
http://archimer.ifremer.fr/doc/00041/15218/12593.pdf
DOI:10.1029/2011JC006989
http://archimer.ifremer.fr/doc/00041/15218/

Éditeur(s) : Elsevier Science Bv
Résumé : Coastal and estuarine systems provide nursery grounds for many marine fish species. Their productivity has been correlated with terrigeneous inputs entering the coastal-estuarine benthic food web, thereby favouring the establishment of fish juveniles. Studies in these ecosystems often describe the nursery as a single large habitat without verifying nor considering the presence of contiguous habitats. Our study aimed at identifying different habitats based on macrozoobenthic communities and morpho-sedimentary characteristics and assessing the trophic interactions between fish juveniles and their benthic preys within these habitats. It included 43 sampling sites covering 5 habitats in which we described taxonomically and quantitatively the invertebrates and fish communities with stable isotopes and gut contents. It suggested that the benthic common sole Solea solea displayed feeding plasticity at the population level, separating the juveniles (G0) from the older fish (G1) into different "feeding sub-populations". Size-based feeding plasticity was also observable in the spatial occupancy of that species in the studied bay. The demersal pouting, Trisopterus luscus, equally used the different habitats but displayed low feeding plasticity across and inside each habitat. Stable isotopes proved to be powerful tools to study the spatial distribution of trophic interactions in complex ecosystems like the bay of Vilaine and to define optimal habitats for fish that use the coastal-estuarine ecosystem as nursery grounds.
Journal Of Sea Research (1385-1101) (Elsevier Science Bv), 2013-08 , Vol. 81 , P. 40-48

Droits : 2013 Elsevier B.V. All rights reserved
http://archimer.ifremer.fr/doc/00151/26226/24327.pdf
DOI:10.1016/j.seares.2013.03.013
http://archimer.ifremer.fr/doc/00151/26226/

Éditeur(s) : HAL CCSD Elsevier
Résumé : Folds with hinge lines subparallel to stretching lineation are common features in shear zones and represent extreme cases of fold modification. However, their microstructures and in particular their kinematic significance remain poorly understood. Here we describe the meso- and micro-scale structures and crystallographic preferred orientation (CPO) of quartz and muscovite from a metric-scale shear-modified fold from Plattjen, Saas Fee, Western Internal Alps. The studied fold is of class-2 and the samples collected around the fold have essentially the same microstructures. Quartz [c]-axes plotted in the tectonic coordinate system exhibit an apparent reverse obliquity on opposing limbs. Muscovite fabrics are controlled essentially by the orientation of {001} planes. If the CPO data are plotted in a common reference frame (e.g. either fold or geographical), all samples exhibit essentially the same patterns for both minerals. In particular, relative to the fold axis and axial surface, the reversal of quartz CPO obliquity on opposing limbs is no longer evident. The small obliquity (~ 15°) between the intersection lineation of the two planes of {001} of muscovite and the fold axis results in the apparent reversal of shear sense on opposite limbs when viewing the CPO related to the macroscopic fabric. The homogeneity of the microstructures and CPOs of quartz and muscovite across the fold support the interpretation that the fold developed during simultaneous activation of heterogeneous and homogeneous simple shear, with the former responsible for fold development and the latter responsible for fold rotation and the overwhelming of the heterogeneous deformation. These processes led to the observed parallelism between fold hinge line and local stretching lineation.
ISSN: 0040-1951

hal-00824537
https://hal.archives-ouvertes.fr/hal-00824537
DOI : 10.1016/j.tecto.2011.03.003

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Whilst it used to affect mostly intravenous drug users and patients who underwent valvular surgery with suboptimal infection control procedures, fungal endocarditis is now mostly observed in patients with severe immunodeficiency (onco-haematology), in association with chronic central venous access and broad-spectrum antibiotic use. The incidence of fungal endocarditis has probably decreased in most developed countries with access to harm-reduction policies (i.e. needle exchange programmes) and with improved infection control procedures during cardiac surgery. Use of specific blood culture bottles for diagnosis of fungal endocarditis has decreased due to optimisation of media and automated culture systems. Meanwhile, the advent of rapid techniques, including fungal antigen detection (galactomannan, mannan/anti-mannan antibodies and β-1,3-d-glucans) and PCR (e.g. universal fungal PCR targeting 18S rRNA genes), shall improve sensitivity and reduce diagnostics delays, although limited data are available on their use for the diagnosis of fungal endocarditis. New antifungal agents available since the early 2000s may represent dramatic improvement for fungal endocarditis: (i) a new class, the echinocandins, has the potential to improve the management of Candida endocarditis owing to its fungicidal effect on yeasts as well as tolerability of increased dosages; and (ii) improved survival in patients with invasive aspergillosis with voriconazole compared with amphotericin B, and this may apply to Aspergillus sp. endocarditis as well, although its prognosis remains dismal. These achievements may allow selected patients to be cured with prolonged medical treatment alone when surgery is considered too risky.
ISSN: 0924-8579

hal-01118441
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01118441
DOI : 10.1016/j.ijantimicag.2014.07.003
PUBMED : 25178919

Éditeur(s) : HAL CCSD European Geosciences Union
Résumé : International audience
Impact of GPS (Global Positioning System) data assimilation is assessed here using a high-resolution numerical weather prediction system at 2.5 km horizontal resolution. The Zenithal Tropospheric Delay (ZTD) GPS data from mesoscale networks are assimilated with the 3DVAR AROME data assimilation scheme. Data from more than 280 stations over the model domain have been assimilated during 15-day long assimilation cycles prior each of the two studied events. The results of these assimilation cycles show that the assimilation of GPS ZTD with the AROME system performs well in producing analyses closer to the ZTD observations in average. Then the impacts of assimilating GPS data on the precipitation forecast have been evaluated. For the first case, only the AROME runs starting a few hours prior the triggering of the convective system are able to simulate the convective precipitation. The assimilation of GPS ZTD observations improves the simulation of the spatial extent of the precipitation, but slightly underestimates the heaviest precipitation in that case compared with the experiment without GPS. The accuracy of the precipitation forecast for the second case is much better. The analyses from the control assimilation cycle provide already a good description of the atmosphere state that cannot be further improved by the assimilation of GPS observations. Only for the latest day (22 November 2007), significant differences have been found between the two parallel cycles. In that case, the assimilation of GPS ZTD allows to improve the first 6 to 12 hours of the precipitation forecast.
ISSN: 0992-7689

hal-00403847
https://hal.archives-ouvertes.fr/hal-00403847
https://hal.archives-ouvertes.fr/hal-00403847/document
https://hal.archives-ouvertes.fr/hal-00403847/file/angeo-27-2739-2009.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We have analyzed the microstructures and crystal preferred orientations (CPO), and calculated the seismic properties of 53 mantle xenoliths from four localities within the North Tanzanian Divergence of the East African rift: two within the rift axis and two in the transverse volcanic belt. Olivine OH concentrations were measured in 15 xenoliths.Most samples have harzburgitic to dunitic compositions and high olivine Mg#. Microstructures and olivine CPO patterns vary strongly depending on the location. In-axis peridotites display mylonitic to porphyroclastic microstructures, which record recent deformation by dislocation creep. Highly stretched orthopyroxenes in mylonites indicate that the deformation was initiated under high stress and probably low temperature. Orthopyroxene replacement by olivine in mylonitic and porphyroclastic peridotites suggest syn-kinematic melt–rock reactions and further deformation under near-solidus conditions. Exsolutions in orthopyroxene imply significant cooling between melt-assisted deformation and xenolith extraction. Late metasomatism is evidenced by the occurrence of veins crosscutting the microstructure and interstitial clinopyroxene and phlogopite. Axial-[100] olivine CPOs predominate, suggesting activation of the high temperature, low pressure [100] {0kl} slip systems and, probably, transtensional deformation. In the volcanic belt, Lashaine peridotites display very coarse-granular textures, indicating deformation by dislocation creep under low deviatoric stress conditions followed by annealing. Axial-[010] olivine CPOs are consistent with transpressional deformation or simultaneous activation of the [100](010) and [001](010) slip systems. Intermediate microstructures and CPOs in Olmani suggests heterogeneous deformation within the volcanic belt. Olivine OH concentrations range between 2 and 12 ppm wt. H2O. No systematic variations are observed between in- and off-axis samples. Maximum P wave azimuthal anisotropy (AVp) ranges between 3.3 and 18.4%, and the maximum S wave polarization anisotropy (AVs) between 2.3 and 13.2%. Comparison between seismic properties of in-axis peridotites and SKS splitting data suggests transtensional deformation in the lithospheric mantle beneath the rift.
ISSN: 0040-1951

hal-01121552
https://hal.archives-ouvertes.fr/hal-01121552
DOI : 10.1016/j.tecto.2014.11.011

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
Seismic anisotropy has been widely studied this last decade, particularly by measuring splitting of vertically propagating core shear waves. The main interest in this technique is to characterize upper mantle flow beneath seismic stations. On the other hand, the major restriction in this method is that a single station gives a single anisotropy measurement. Alternative methods have been developed in order to avoid this restriction. An accurate determination of upper mantle seismic anisotropy beneath a seismic station may allow one, by doing anisotropy correction, to characterize remote or deeper anisotropy. The Geoscope network is ideal for this purpose because it is composed of a large set (about 26) of high-quality, broadband seismometers globally distributed and because some of these stations have run for more than 10 years and most of them for more than 5 years. We selected about 100 events at each site, generally of magnitude (m b) > 6.0, and we performed systematic measurements of the splitting parameters (fast polarization direction φ and delay time δt) on SKS, SKKS, and PKS phases. Splitting on oceanic islands has been difficult to observe owing to the low quality of the signal but also perhaps owing to complex upper mantle structures beneath the stations. Station KIP (Kipapa, Hawaii) in the Pacific is the only oceanic Geoscope station with a clear anisotropy. We determined well-constrained splitting parameters for 10 of the 17 continental stations that may be explained by a single anisotropic layer. The poor correlation between fast polarization directions and the absolute plate motion together with the apparent incoherence between the plate velocities and the observed delay times suggest that a simple drag-induced asthenospheric flow alone fails to explain most of the observations. For some stations located on or near major lithospheric structures (TAM, Tamanrasset, Algeria, for instance), we observe a good correlation between fast polarization directions and regional structures. At station SCZ (Santa Cruz, California), we found clear variations of the splitting parameters as a function of the event backazimuth, compatible with two layers of anisotropy. Three stations (CAN (Canberra), HYB (Hyderabad, India) and SSB (Saint Sauveur Badole, France)) seem to be devoid of detectable anisotropy.
ISSN: 2169-9313

hal-01388830
http://hal.univ-reunion.fr/hal-01388830
http://hal.univ-reunion.fr/hal-01388830/document
http://hal.univ-reunion.fr/hal-01388830/file/Barruol_anisoGeoscope_JGR1999.pdf
DOI : 10.1029/1999JB900033

Éditeur(s) : HAL CCSD American College of Sports Medicine (ACSM)
Résumé : International audience
PURPOSE AND METHODS: To determine the effects of cycling on a subsequent triathlon run, nine male triathletes underwent four successive laboratory trials: 1) an incremental treadmill test, 2) an incremental cycle test, 3) 30 min of cycling followed by 5 km of running (C-R), and 4) 30 min of running followed by 5 km of running (R-R). Before and 10 min after the third and fourth trials, the triathletes underwent pulmonary function testing including spirometry and diffusing capacity testing for carbon monoxide (DL(CO)). During the C-R and R-R trials, arterialized blood samples were obtained to measure arterial oxygen pressure (PaO2). During all trials, ventilatory data were collected every minute using an automated breath-by-breath system. RESULTS: The results showed that 1) the oxygen uptake (VO2) observed during subsequent running was similar for the C-R and R-R trials; 2) the ventilatory response (VE) during the first 8 min of subsequent running was significantly greater in the C-R than in R-R trial (P < 0.05); 3) only the C-R trial induced a significant increase (P < 0.05) in residual volume (RV), functional residual capacity (FRC), and the ratio of residual volume to total lung capacity (RV/TLC); and 4) although a significant decrease (P < 0.05) in DL(CO) was noted after C-R, no difference between the two exercise trials was found for the maximal drop in PaO2. CONCLUSIONS: We concluded that 1) the C-R trial induced specific alterations in pulmonary function that may be associated with respiratory muscle fatigue and/or exercise-induced hypoxemia, and 2) the greater VE observed during the first minute of running after cycling was due to the specificity of cycling. This reinforces the necessity for triathletes to practice multi-trial training to stimulate the physiological responses experienced during the swim-cycle and the cycle-run transitions.
ISSN: 0195-9131

hal-00720412
https://hal.univ-antilles.fr/hal-00720412
https://hal.univ-antilles.fr/hal-00720412/document
https://hal.univ-antilles.fr/hal-00720412/file/Article.pdf

Éditeur(s) : Elsevier Science Bv
Résumé : In tropical shrimp ponds, the increasing of feed input, concomitantly with the stocking shrimp biomass, induces an eutrophication of the ecosystem. Although difficult to maintain, its stability is required to guarantee the success of the culture. A 110-day period of phytoplankton and bacterioplankton stock and dynamics in an earthen pond (1.2 ha area, 1 m depth) was monitored using flow cytometry to provide baseline information on community characteristics and ecosystem instability. Seven autotrophic cell types were identified over the whole sampling period. Prokaryotic cells included Synechococcus sp., a group named UNK which presented an atypical new flow cytometric signature and picoeukaryotes (PEUK). Nanophytoplankton cells were represented by 4 groups: NAN1, NAN2, NAN3 and Cryptophytes. During the first part of the survey, picophytoplankton dominated the phytoplanktonic assemblage. The mean abundance of total cells (up to 8 x 10(6) cells mL(-1)) was among the highest recorded in marine and brackish waters. Bacterial abundance and production ranged from 0.8 to 5.1 x 10(7) cells mL(-1) and from 30 to 110 mu g C L-1 h(-1). A shift from pico to nanophytoplankton abundance was observed for a few days from d 96. During this period, heterotrophic bacteria production and abundance suddenly dropped, implying a change in the functioning of the microbial loop. This shift was concomitant with a significant shrimp mortality outbreak due to Vibrio penaeicida, the etiological agent of a disease known as Syndrome 93, which affects the shrimp industry in New Caledonia. This survey suggests that flow cytometric analysis could be used for the monitoring of aquaculture systems to improve our understanding of the complex phytoplankton and bacterial dynamics of these systems and its potential influence on disease development. (c) 2010 Elsevier B.V. All rights reserved.
Aquaculture (0044-8486) (Elsevier Science Bv), 2010-12 , Vol. 310 , N. 1-2 , P. 112-121

Droits : 2010 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00029/14068/11312.pdf
DOI:10.1016/j.aquaculture.2010.10.022
http://archimer.ifremer.fr/doc/00029/14068/