Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Cytochrome P450 aromatase (P450arom; aromatase) is a microsomal enzyme involved in the production of endogeneous sex steroids by converting testosterone into oestradiol. Aromatase is the product of the cyp19a1 gene and plays a crucial role in the sexual differentiation of the brain and in the regulation of reproductive functions. In the brain of mammals and birds, expression of cyp19a1 has been demonstrated in neuronal populations of the telencephalon and diencephalon. By contrast, a wealth of evidence established that, in teleost fishes, aromatase expression in the brain is restricted to radial glial cells. The present study investigated the precise neuroanatomical distribution of cyp19a1 mRNA during brain development in Xenopus laevis (late embryonic to juvenile stages). For this purpose, we used in situ hybridisation alone or combined with the detection of a proliferative (proliferating cell nuclear antigen), glial (brain lipid binding protein, Vimentin) or neuronal (acetylated tubulin; HuC/D; NeuroβTubulin) markers. We provide evidence that cyp19a1 expression in the brain is initiated from the very early larval stage and remains strongly detected until the juvenile and adult stages. At all stages analysed, we found the highest expression of cyp19a1 in the preoptic area and the hypothalamus compared to the rest of the brain. In these two brain regions, cyp19a1-positive cells were never detected in the ventricular layers. Indeed, no co-labelling could be observed with radial glial (brain lipid binding protein, Vimentin) or dividing progenitors (proliferating cell nuclear antigen) markers. By contrast, cyp19a1-positive cells perfectly matched with the distribution of post-mitotic neurones as shown by the use of specific markers (HuC/D, acetylated tubulin and NeuroβTubulin). These data suggest that, similar to that found in other tetrapods, aromatase in the brain of amphibians is found in post-mitotic neurones and not in radial glia as reported in teleosts.
ISSN: 0953-8194

hal-00994513
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00994513
DOI : 10.1111/jne.12142
PUBMED : 24612124

Éditeur(s) : HAL CCSD Elsevier
Résumé : This paper is the first presentation of a project called GHYRAF (Gravity and Hydrology in Africa) devoted to the detailed comparison between models and multidisciplinary observations (ground and satellite gravity, geodesy, hydrology, meteorology) of the variations of water storage in Africa from the Sahara and part to the monsoon equatorial part. We describe the various actions planned in this project. We first detail the actions planned in gravimetry which consist in two main surface gravity experiments: on the one hand the periodic repetition of absolute gravity measurements along a north-south monsoonal gradient of rainfall in West Africa, going from Tamanrasset (20 mm/year) in southern Algeria to Djougou (1200 mm/year) in central Benin; on the other hand the continuous measurements at Djougou (Benin) with a superconducting gravimeter to monitor with a higher sampling rate the gravity changes related to an extreme hydrological cycle. Another section describes the actions planned in GPS which will maintain and develop the present-day existing network in West Africa. The third type of actions deals with hydrology and we review the three sites that will be investigated in this joint hydrogeophysics project namely Wankama (near Niamey) and Bagara (near Diffa) in the Niger Sahelian zone and Nalohou (near Djougou) in the Benin monsoon zone. We also address the question of the ground truth of satellite-derived missions: in this context the GHYRAF project will lead to test the hydrology models by comparison both with in situ and satellite data such as GRACE, as well as to an important increase of our knowledge of the seasonal water cycle in Africa. We finally present preliminary results in GPS based on the analysis of the vertical motion of the Djougou site. The resulting absolute gravity changes related to the 2008 monsoon are finally given.
ISSN: 0264-3707

hal-00475660
https://hal.archives-ouvertes.fr/hal-00475660
DOI : 10.1016/j.jog.2009.09.014

Éditeur(s) : Taylor & Francis Ltd
Résumé : A new method is developed to estimate daily turbulent airsea fluxes over the global ocean on a 0.25 degrees grid. The required surface wind speed (w(10)) and specific air humidity (q(10)) at 10m height are both estimated from remotely sensed measurements. w(10) is obtained from the SeaWinds scatterometer on board the QuikSCAT satellite. A new empirical model relating brightness temperatures (T-b) from the Special Sensor Microwave Imager (SSM/I) and q(10) is developed. It is an extension of the author's previous q(10) model. In addition to T-b, the empirical model includes sea surface temperature (SST) and airsea temperature difference data. The calibration of the new empirical q(10) model utilizes q(10) from the latest version of the National Oceanography Centre airsea interaction gridded data set (NOCS2.0). Compared with mooring data, the new satellite q(10) exhibits better statistical results than previous estimates. For instance, the bias, the root mean square (RMS), and the correlation coefficient values estimated from comparisons between satellite and moorings in the northeast Atlantic and the Mediterranean Sea are 0.04gkg(1), 0.87gkg(1), and 0.95, respectively. The new satellite q(10) is used in combination with the newly reprocessed QuikSCAT V3, the latest version of SST analyses provided by the National Climatic Data Center (NCDC), and 10m air temperature estimated from the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalyses (ERA-Interim), to determine three daily gridded turbulent quantities at 0.25 degrees spatial resolution: surface wind stress, latent heat flux (LHF), and sensible heat flux (SHF). Validation of the resulting fields is performed through a comprehensive comparison with daily, in situ values of LHF and SHF from buoys. In the northeast Atlantic basin, the satellite-derived daily LHF has bias, RMS, and correlation of 5Wm(2), 27Wm(2), and 0.89, respectively. For SHF, the statistical parameters are 2Wm(2), 10Wm(2), and 0.94, respectively. At global scale, the new satellite LHF and SHF are compared to NOCS2.0 daily estimates. Both daily fluxes exhibit similar spatial and seasonal variability. The main departures are found at latitudes south of 40 degrees S, where satellite latent and sensible heat fluxes are generally larger.
International Journal Of Remote Sensing (0143-1161) (Taylor & Francis Ltd), 2013-07 , Vol. 34 , N. 14 , P. 5243-5261

Droits : 2013 Taylor & Francis
http://archimer.ifremer.fr/doc/00137/24825/23575.pdf
DOI:10.1080/01431161.2013.787502
http://archimer.ifremer.fr/doc/00137/24825/

Éditeur(s) : HAL CCSD
Résumé : National audience
Un ensemble de données sur l’environnement géologique despéridotites de la Zone Nord-Pyrénéenne a été obtenu dans lecadre des programmes ANR Pyramid et RGF-BRGM consacrésà l’évolution géodynamique des Pyrénées. Ces données représententdes contraintes indispensables pour l’étude des processus del’exhumation du manteau, de l’amincissement de la croûte continentaleet de sa disparition complète lors de l’ouverture desbassins transtensifs albo-cénomaniens. On y trouve : (1) de nouveauxlevés géologiques de détail autour des lherzolites de Lherz-Freychinède-Vicdessos-Bestiac-Prades et d’Urdach-Les Pernes et(2) des analyses multi-méthodes des métasédiments de la couvertureprérift et du socle paléozoïque adhérent au manteau :composition des assemblages du métamorphisme HT, températuresmaximales par spectrométrie RAMAN sur la m.o., fabriquede la calcite par EBSD, inclusions fluides et isotopes stables dansles marbres et veines associées, datations U-Th-Pb in situ. Cesdonnées permettent d’estimer les conditions thermiques lors de laremontée du manteau et de sa mise à l’affleurement. Nous montronsune variabilité remarquable de l’Ouest vers l’Est.A l’Ouest, le manteau est exhumé à l’Albien sup. - Cénomanieninf. en perçant une couverture mésozoïque prérift qui n’a pas étéchauffée à plus de 250C. La croûte continentale supérieure y estréduite en lames ductiles extrêmement amincies puis cataclaséeset remaniées sur le fond ultrabasique avec des fragments de manteauet de la couverture prérift, durant le dépôt du flysch noir. Latempérature augmente au cours du Cénomanien (480C) dans leszones où le manteau n’a pas été mis à l’affleurement. Le Triassupérieur se transforme profondément (talc-chlorites) et perd sacomposante évaporitique. La couverture prérift décollée joue unrôle majeur comme couvercle isotherme, suivi en cela par les flyschsalbiens puis cénomaniens.A l’Est, le manteau perce à travers une couverture chauffée localementà plus de 600C. Le Keuper y est réduit à quelquesdécimètres de grès et brèches riches en saphirine. La croûtesupérieure a été presque totalement éliminée tectoniquement, maisdes granulites sont remaniées à côté des péridotites et des marbresdans les brèches recouvrant le manteau exhumé.Ces données de terrain représentent les contraintes de base pourconstruire les modèles d’amincissement crustal. La variabilitémise en évidence (gradient thermique et présence ou absence decroûte profonde remaniée) ne permet pas de proposer un modèled’amincissement simple et unique. Cependant, toutes ces donnéesindiquent que la croûte moyenne à supérieure se comporteductilement sous les écrans thermiques de la couverture prériftet synrift, mobiles sur le Keuper. Un modèle de marge passivedistale faisant appel à des blocs continentaux rigides de type ”extensional allochthons ” ne peut s’appliquer ici. Sur la base deces données géologiques, nous mettons donc en avant un nouveaumodèle de type marge distale chaude plus ou moins transtensive.
RST 2016, livre des résumés
Caen, France

insu-01388463
https://hal-insu.archives-ouvertes.fr/insu-01388463

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
AimThe global biodiversity crisis requires the identification of regions with high evolutionary potential, i.e. evolutionary hotspots (evospots). We created an analytical framework based on comparative phylogeography and coalescent methods to assess the dynamics of diversification and population persistence in the reef ecosystem of a little-studied region: the Southwestern Indian Ocean (SWIO).LocationCoral reefs of the SWIO, with comparative data from the Pacific Ocean.MethodsWe generated sequences of mitochondrial DNA (COI and 16S) for 10 widespread brittle-stars (345 specimens) from 21 localities (8 in the SWIO). We analysed them by combining comparative phylogeography approaches, coalescent-based methods, molecular clocks and the concept of evolutionarily significant units (ESUs) to draw conclusions about the drivers of biodiversity in the region.ResultsCryptic diversity was prevalent, increasing lineage diversity within the 10 nominal species by 70% within the SWIO and by 200% across the Indo-West Pacific. All seven new SWIO lineages meet the criteria for ESUs and at least six are biological species. We detected likely intraregional diversifications dating to the Plio-Pleistocene, supporting the SWIO as a generator of biodiversity. Geographical restriction of ESUs, long coalescent times (> 80 ka) and old in situ diversification (> 1 Ma) point to the persistence of populations over multiple glacio-eustatic cycles. We provide data suggesting demographic expansion during sea-level high stands. Regional connectivity was lower, and cryptic differentiation higher in lecithotrophs than in planktotrophs.Main conclusionsThe analytical framework based on a biodiversity survey makes it possible to identify evospots by assessing the potential of a region to maintain and generate biodiversity and by evaluating the evolutionary processes and potential drivers at play.
ISSN: 0305-0270

hal-01369697
http://hal.univ-reunion.fr/hal-01369697
DOI : 10.1111/jbi.12155

Éditeur(s) : Université Européenne de Bretagne
Résumé : The southwest Pacific results from the fragmentation of Gondwanaland since the Cretaceous time. The purpose of the current PhD work is to deepen our understanding of the history of the New Caledonia and Fairway basins, located west of New Caledonia, in order to better constrain the geodynamical evolution of the SW Pacific from Cretaceous to Oligocene. The analysis of new geophysical data has led to distinguish 3 main phases of this fragmentation: 1 Mid Cretaceous formation of the Fairway-Aotea Basin in a continental intra-arc position. The formation of this basin reflects the initial stage of continental fragmentation of the Eastern Gondwana margin. The causes of this fragmentation are to be searched for in a major change of the dynamics of the peri-Pacific subduction zone. 2 Latest late Eocene local deformation of the Northern NCB, synchronously with the New Caledonian obduction. We suggest that as the ophiolitic nappe was being obducted onto New Caledonia, the NC Basin subsided under the effect of the loading and underthrusted to accommodate the compressional deformation as a foreland flexural basin. 3 Regional Eocene Oligocene subsidence of the structures linking NC to New Zealand. The morphostructural style of this deformation leads us to suggest that detachment of the lower crust is the cause of subsidence. We therefore propose a model in which the renewal of the Australia-Pacific convergent plate boundary around 45 Ma would have driven the lithosphere to thicken, leading to a root instability and to its detachment in the mantle. These new results have regional petroleum implications, which are discussed in the PhD.
Le Sud-Ouest Pacifique est le résultat de la fragmentation de la marge Est du Gondwana depuis le Crétacé. L'objet du présent travail de thèse est d'approfondir la connaissance des bassins de Nouvelle-Calédonie et de Fairway, situés à l'Ouest de la NC, afin de préciser l'évolution géodynamique du SO Pacifique du Crétacé à l'Oligocène. L'analyse de nouvelles données géophysiques a permis de dégager 3 étapes de cette fragmentation: 1 Formation du Bassin de Fairway-Aotea au Crétacé moyen en position intra-arc continental. La formation de ce bassin reflète les prémices de la déchirure continentale de la marge Est Gondwanienne dont la cause est à rechercher dans un changement de la dynamique de la subduction. 2 Déformation locale de la partie Nord du BNC à l'Eocène terminal synchrone à l'obduction Néo Calédonienne. Nous proposons ainsi un modèle selon lequel le BNC aurait subsidé et réagi comme un bassin flexural d'avant-pays suivant un processus de sous-charriage, au fur et à mesure que la nappe progressait sur le bâti Calédonien. 3 Subsidence Eocène Oligocène régionale affectant les structures reliant la Nouvelle-Zélande à la NC. Les traits morphostructuraux de cette déformation nous permettent d'émettre l'hypothèse que l'ablation d'une partie de la croûte inférieure de ce système serait responsable de la subsidence. Nous proposons ainsi un modèle dans lequel la reprise de la convergence vers 45 Ma entre les plaques Australienne et Pacifique aurait entraîné un épaississement crustal de l'ensemble aboutissant à une instabilité gravitaire de sa racine et provoquant son détachement dans le manteau. Ces nouveaux résultats ont des implications pour le potentiel pétrolier régional.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2009/these-6520.pdf
http://archimer.ifremer.fr/doc/2009/sup-6520.pdf
http://archimer.ifremer.fr/doc/00000/6520/

Éditeur(s) : IEEE
Résumé : Two approaches of ocean color data merging were tested and compared in the North and Equatorial Atlantic Basin: the weighted averaging and the objective analysis. The datasets used were the daily level-3 binned data of chlorophyll-a from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Moderate Resolution Imaging Spectroradiometer on the Aqua satellite over the year 2003, which is the first common full year of operation. Since they represent input for both approaches, matchups between the satellite and the in situ data from the SeaWiFS Bio-optical Archive and Storage System and the Atlantic Meridional Transect were first studied to compute a spatial map of the root mean-square error and of the bias. Because of the log distribution of the chlorophyll fields, each approach was applied to untransformed and log-transformed values. The application of the weighted averaging to log-transformed values does not show significant differences in comparison to its application to untransformed values. This is not the case, however, for the objective analysis that gives better results when applied to logtransformed values. Both approaches give combined chlorophyll data of equivalent quality, although the objective analysis could be improved with a better statistical characterization of noise and signal covariance. The main advantage of the objective analysis is its ability to interpolate in space (and time) by taking into account the characteristic scales of chlorophyll-a. As a result, the spatial coverage of the combined data is at least twice as large in the case of objective analysis than weighted averaging. OCR NOT CONTROLLED
IEEE (0196-2892) (IEEE), 2006-11 , Vol. 44 , N. 11 , P. 3436-3451

Droits : 2006 IEEE
http://archimer.ifremer.fr/doc/2006/publication-3631.pdf
DOI:10.1109/TGRS.2006.878441
http://archimer.ifremer.fr/doc/00000/3631/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Madeira Sn-Nb-Ta deposit corresponds to the albite-enriched facies of Madeira granite (Madeira Suite) that is part of a NE-SW alignment of three granitic bodies. Structural analyses suggest that the albite-enriched granite emplacement and development of related structures occurred in a different tectonic setting than earlier facies of the granitic bodies in the NE-SW alignment and that the structure was dominated by a N-NE-trending shortening related to a left-lateral motion along a NE-SW corridor within a Riedel shear. Three types of structures (flat-lying, near vertical fractures, and geodes/miaroles) concentrated the last magmatic-related fluid in the albite-enriched granite. U-Pb in situ zircon dating of the albite-enriched granite yielded an age of 1,822 ± 22 Ma. The other granitic plutons of the Madeira Suite, Água Boa granite (topaz-granite facies), and Europa per-alkaline granite formed at 1,825 ± 14 Ma, 1,831± 11 Ma, and 1,839 ± 10 Ma, respectively. The granite bodies of the Madeira Suite occur in an area occupied by a cauldron complex composed of volcanic sequences (Iricoumé Group) and associated A-type granites (Mapuera Suite), and their formation was controlled by the reactivation of the cauldron structures and the pre-existing structures. The gap between the cauldron complex and the Madeira Suite is no greater than 35 Ma. The geological evolution was reanalyzed from the perspective of an entire extensional environment where three successive episodes of A-type magmatism and basin formation (Urupi Formation) occurred. The data and interpretations of this work imply crucial constraints on the petrologic models proposed for the albite-enriched granite and, consequently, on the genesis of the Madeira deposit
ISSN: 0301-9268

insu-00939888
https://hal-insu.archives-ouvertes.fr/insu-00939888
https://hal-insu.archives-ouvertes.fr/insu-00939888/document
https://hal-insu.archives-ouvertes.fr/insu-00939888/file/BastosNeto-PrecambrianResearch-2014.pdf
DOI : 10.1016/j.precamres.2013.12.021

Éditeur(s) : ESA Publication
Résumé : Satellite remote sensing has emerged as an essential and necessary observing system to acquire global information about the state of the ocean. Complemented with in situ observing networks, the ultimate goals are to be able to make accurate estimates of selected key sets of geophysical variables, with the intention of either making operational predictions across time and spatial boundaries, or advancing fundamental knowledge through development of empirical relationships and theoretical models. For satellite oceanography, improvements are then constantly being sought in our understandings of the geophysical processes, the sensor physics, the electromagnetic and microwave properties and interactions at the complex air-sea interface. Challenges appear as unlimited as the variety of sea surface dynamics and boundary layer meteorological conditions with their broad range of spatial and temporal scales across the globe. To face these challenges, numerous efforts took places over the passed decade to build an ever-increasing quality, quantity, duration and integration of ocean observations. In parallel, simulation capabilities largely improved. All these efforts are then all critically calling for improved methodologies to better structure the wealth of information that is made readily accessible. This latter aspect is a very demanding new component for future multidisciplinary scientific research. Major innovations to consolidate sensor data repositories, to automate tailored queries, to extract, reveal and quantify relationships will then closely associate computer science developments and applied statistics with comprehensive theoretical and experimental thematic studies.
Proceedings of OceanObs'09: Sustained Ocean Observations and Information for Society (ESA Publication), 2010

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00029/14046/11241.pdf
DOI:10.5270/OceanObs09.pp.12
http://archimer.ifremer.fr/doc/00029/14046/

Éditeur(s) : ICES 2008 Annual Science Conference, 22-26 september 2008, HALIFAX, CANADA
Résumé : Since 2000, Ifremer has been implemented a Fisheries Information System (FIS), in strong collaboration with the DPMA (Direction of fisheries and aquaculture of the French Ministry of Agriculture and Fisheries). The FIS aims at building an operational and multidisciplinary monitoring network for scientific purposes, allowing a comprehensive view of fishery systems including their biological, technical, environmental and economical components. The objectives of the FIS are (i) to provide the specifications and methodologies for the collection, storage and processing of fisheries data, with the constant concern to harmonise all these procedures on a national scale, (ii) to improve data management system and access to data for a wide-spread public, and (iii) to produce and distribute relevant datasets, indicators and synthesis, for understanding and evaluation, including bio-economic diagnostics of the fisheries, and assessment of the short and long-term impacts of fisheries management scenario and measures. The FIS covers all the French fisheries, including overseas territories and small-scale fisheries, for which data are often hardly available or missing, whereas two thirds of the French vessels are less than 12 meters long. The challenge was to establish a statistical and an integrated approach supporting bio-ecological and economic issues. To further an integrated analysis of the fishery systems, the wide range kinds of data - including acoustic surveys, biological in-situ observations, environmental observations, as well as fishing statistics (landings and efforts) or economic data - are managed in a single data management system, based on an integrated relational data base with geographical facilities.

Droits : 2008 ICES
http://archimer.ifremer.fr/doc/00059/17002/14504.pdf
http://archimer.ifremer.fr/doc/00059/17002/

Éditeur(s) : HAL CCSD springer
Résumé : International audience
In this paper, we address the problem of flood prediction in complex situations. We present an original solution in order to achieve the main goals of accuracy, flexibility and readability. We propose the SM2D modular data driven approach that provides predictive models for each sub-process of a global hydrological process. We show that this solution improves the predictive accuracy regarding a global approach. The originality of our proposition is threefold: (1) the predictive model is defined as a set of aggregate variables that act as classifiers, (2) an evolutionary technique is implemented to find best juries of such classifiers and (3) the flood process complexity problem is addressed by searching for sub-models on sub-processes identified partly by spatial criteria. The solution has proved to perform well on flash flood phenomena of tropical areas known to be hardly predictable. It was indeed successfully applied on a real caribbean river dataset after both preprocessing and preliminary analysis steps presented in the paper.
Lecture notes in computer science
Singapour, Singapore

hal-00878780
https://hal.archives-ouvertes.fr/hal-00878780
DOI : 10.1007/978-3-642-40897-7_13

Éditeur(s) : Springer
Résumé : While it is well known that the ocean is one of the most important component of the climate system, with a heat capacity 1,100 times greater than the atmosphere, the ocean is also the primary reservoir for freshwater transport to the atmosphere and largest component of the global water cycle. Two new satellite sensors, the ESA Soil Moisture and Ocean Salinity (SMOS) and the NASA Aquarius SAC-D missions, are now providing the first space-borne measurements of the sea surface salinity (SSS). In this paper, we present examples demonstrating how SMOS-derived SSS data are being used to better characterize key land–ocean and atmosphere–ocean interaction processes that occur within the marine hydrological cycle. In particular, SMOS with its ocean mapping capability provides observations across the world’s largest tropical ocean fresh pool regions, and we discuss from intraseasonal to interannual precipitation impacts as well as large-scale river runoff from the Amazon–Orinoco and Congo rivers and its offshore advection. Synergistic multi-satellite analyses of these new surface salinity data sets combined with sea surface temperature, dynamical height and currents from altimetry, surface wind, ocean color, rainfall estimates, and in situ observations are shown to yield new freshwater budget insight. Finally, SSS observations from the SMOS and Aquarius/SAC-D sensors are combined to examine the response of the upper ocean to tropical cyclone passage including the potential role that a freshwater-induced upper ocean barrier layer may play in modulating surface cooling and enthalpy flux in tropical cyclone track regions.
Surveys In Geophysics (0169-3298) (Springer), 2014-05 , Vol. 35 , N. 3 , P. 681-722

Droits : Springer Science+Business Media Dordrecht 2013
http://archimer.ifremer.fr/doc/00152/26334/24430.pdf
DOI:10.1007/s10712-013-9244-0
http://archimer.ifremer.fr/doc/00152/26334/

Résumé : Les pathologies inflammatoires démyélinisantes primitives du système nerveux central (SNC) sont dominées par deux entités : la sclérose en plaques (SEP) et la neuromyélite optique (NMO). Ces deux pathologies se différencient par : 1. leur phénotype, la NMO se caractérisant par une myélite extensive dans le plan transversal et longitudinal et peu de lésions encéphaliques initiales ; 2. leur sévérité, le pronostic de la NMO étant moins bon que celui de la SEP ; 3. leur mécanisme immunologique, puisque l’immunité humorale domine nettement dans la NMO, cette pathologie répondant peu ou pas aux traitementshabituellement prescrits dans la SEP. Un anticorps sérique (IgG-NMO) a été retrouvé chez les patients atteints de NMO avec une sensibilité de 50-70% et une spécificité de 90-100%. Cet anticorps a pour cible le principal canal hydrique du SNC, l’aquaporine-4 (AQP4), qui se situe principalement sur les pieds astrocytaires jalonnant la barrière hémato-encéphalique. La SEP est relativement familière des neurologues car décrite sur le plan épidémiologique et dans son histoire naturelle depuis plus d’un siècle à travers de larges séries réalisées parfois en population générale. Son approche thérapeutique progresse suite à des essais contrôlés qui s’accumulent depuis maintenant près de 20 ans. Toutefois, la majorité des travaux ont été effectués chez les populations Caucasiennes en raison de sa plus grande fréquence dans ces populations. A l’inverse, la NMO garde encore un relatif mystère à cause de sa relative rareté, l’établissement très récent de critères diagnostiques et une physiopathologie très récemment éclaircie par la découverte de l’IgG-NMO qui a indiscutablement suscité un regain d’intérêt de cette affection. Ainsi, son incidence est quasiment inconnue de même que sa susceptibilité génétique. La progression du handicap de la NMO qu’il soit visuel ou moteur à l’évidence sévère, ne repose toujours pas sur des chiffres précis, la description des lésions neuroradiologiques reste encore très embryonnaire. Enfin, même s’il existe un consensus pour traiter énergiquement les poussées de NMO et les espacer, il n’existe quasiment aucune étude prospective.
Introduction: Aim of the study is to describe épidemiology, phenotype and treatment of demyelinating inflammatory diseases of the central nervous system (CNS) namely multiple sclerosis (MS) and neuromyelitis optica (NMO) in French West Indies.Epidemiology: MS emerged in the French West Indian (FWI) population with an incidence of 1.27/100 000 (CI 95%: 1.16-1.38) for the period 1992-2007 while incidence of NMO remained stable at 0.19/100,000 (CI 95%: 0.15–0.23). Both migration in Metropolitean France (MF) and decrease of sun exposure were risk factors for MS acquisition in FWI. Phenotype and treatment of NMO: NMO is a very rapidly disabling disease with median times to reach DSS 3, 6 and 8 of one year, 8 years and 22 years respectively. However, treatment by plasma exchanges were shown to reduce sequellae of NMO attacks ; mitoxantrone and rituximab reduced significantly annualized relapse rate (ARR) from 1.7 to 0.29 (p<10-4) and from 1,34 to 0,56 (p=0.0005) respectively, improving dramatically natural course of NMO.Phenotype and treatment of MS: Absence of Migration in MF in MS patients was found to be the strongest independent predictive factor of disability progression to DSS 6 (hazard ratio, 2.59; p=0.0002); beside short time to DSS3 (p=0.005), later age at onset (p=0.005), and multi-symptomatic onset (p=0.03). Treatment of MS by interferon beta-1 had a moderate impact in MS while natalizimab proved to be highly effective by reducing drastically ARR and inflammatory parameters on magnetic resonance imaging. Conclusion: Spectrum of demyelinating inflammatory disorders of CNS has reversed in French West Indies with overrepresentation of MS. Agressive therapy is needed to improve prognosis of NMO. Rapidly increasing of its incidence makes MS a new public health problem in French West Indies.

http://www.theses.fr/2012AGUY0511/document

Éditeur(s) : Amer Geophysical Union
Résumé : An analysis is presented for the spatial and intensity distributions of North Atlantic extreme atmospheric events crossing the buoyant Amazon-Orinoco freshwater plume. The sea surface cooling amplitude in the wake of an ensemble of storm tracks traveling in that region is estimated from satellite products for the period 1998-2012. For the most intense storms, cooling is systematically reduced by approximate to 50% over the plume area compared to surroundings open-ocean waters. Historical salinity and temperature observations from in situ profiles indicate that salt-driven vertical stratification, enhanced oceanic heat content, and barrier-layer presence within the plume waters are likely key oceanic factors to explain these results. Satellite SMOS surface salinity data combined with in situ observations are further used to detail the oceanic response to category 4 hurricane Igor in 2010. Argo and satellite measurements confirm the haline stratification impact on the cooling inhibition as the hurricane crossed the river plume. Over this region, the SSS mapping capability is further tested and demonstrated to monitor the horizontal distribution of the vertical stratification parameter. SMOS SSS data can thus be used to consistently anticipate the cooling inhibition in the wake of TCs traveling over the Amazon-Orinoco plume region.
Journal Of Geophysical Research-oceans (0148-0027) (Amer Geophysical Union), 2014-12 , Vol. 119 , N. 12 , P. 8271-8295

Droits : 2014. American Geophysical Union. All Rights Reserved.
http://archimer.ifremer.fr/doc/00252/36326/34855.pdf
http://archimer.ifremer.fr/doc/00252/36326/34856.pdf
DOI:10.1002/2014JC010107
http://archimer.ifremer.fr/doc/00252/36326/

Éditeur(s) : HAL CCSD
Résumé : International audience
The identification and economic valuation of ecosystem services (ES) are becoming important components of coral reef management. In many contexts, protection of human assets against coastal floods is one of the most important ES provided by coral reefs. The methods utilized to characterize this ES should be able to accommodate situations with low data availability, without sacrificing robustness. In this paper, we suggest such an approach that utilizes expert opinion and does not require copious amounts of data. Our primary objective is to find a balance between simple and complex models that can be used in a data scarce environment, to produce an economic valuation of the coral reef ES of protection against coastal floods. The approach has three steps: (i) identify geographic zones and assets at risk, (ii) identify the contributing role of coral reefs in the protection of coasts and, (iii) value the annual repair costs of assets through the avoided damage cost approach. The proposed method seems appropriate for advocacy with policy makers, but appears to be less effective for small scale approaches, such as those required for Payment for ES negotiations or marine spatial planning.
Ecosystem Services

hal-01359394
https://hal-univ-perp.archives-ouvertes.fr/hal-01359394
DOI : 10.1016/j.ecoser.2016.07.005

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Gibraltar arc, spans a complex portion of the Africa-Eurasia plate boundary marked by slow oblique convergence and intermediate and deep focus seismicity. The seemingly contradictory observations of a young extensional marine basin surrounded by an arcuate fold-and-thrust belt, have led to competing geodynamic models (delamination and subduction). Geophysical data acquired in the past decade provide a test for these models and support a narrow east-dipping, subduction zone. Seismic refraction studies indicate oceanic crust below the western Gulf of Cadiz. Tomography of the upper mantle reveals a steep, east-dipping high P-wave velocity body, beneath Gibraltar. The anisotropic mantle fabric from SKS splitting shows arc-parallel "fast directions", consistent with toroidal flow around a narrow, westward retreating subducting slab. The accompanying WSW advance of the Rif-Betic mountain belt has constructed a thick pile of deformed sediments, an accretionary wedge, characterized by west-vergent thrust anticlines. Bathymetric swath‐mapping images an asymmetric embayment at the deformation front where a 2 km high basement ridge has collided. Subduction has slowed significantly since 5 Ma, but deformation of recent sediments and abundant mud volcanoes suggest ongoing activity in the accretionary wedge. Three possible origins for this deformation are discussed; gravitational spreading, overall NW-SE convergence between Africa and Iberia and finally a WSW tectonic push from slow, but ongoing roll-back subduction. In the absence of arc volcanism and shallow dipping thrust type earthquakes, evidence in favor of present-day subduction can only be indirect and remains the object of debate. Continued activity of the subduction offers a possible explanation for great (M > 8.5) earthquakes known to affect the area, like the famous 1755 Great Lisbon earthquake. Recent GPS studies show SW motion of stations in N Morocco at velocities of 3-6 mm/yr indicating the presence of an independent block, a "Rif-Betic-Alboran" microplate, situated between Iberia and Africa.
ISSN: 0040-1951

insu-00769762
https://hal-insu.archives-ouvertes.fr/insu-00769762
DOI : 10.1016/j.tecto.2012.08.038

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Over the last two decades, climate change has become a major environmental and public health concern due to the increase of the mean temperature on the Earth and its consequences on extreme meteorological events such as floods and droughts. These events induce very low or very high river flows that may impair surface water quality, and therefore result in potential health impacts when used for drinking water production. The present study aims at assessing the impact of hydrologic regime on surface water quality with a particular emphasis on total organic carbon (TOC) and nitrate. Water quality data from three French rivers acquired over a 27 years period, from January 1983 to December 2009, show the influence of extreme flows. Variation in TOC and nitrate concentrations showed opposite patterns for the whole range of flow rate (from less than 10% up to more than 100% of the mean flow). Regarding fluxes, TOC increased continuously with flow rate while nitrate was stable for very high discharges. The C/N ratio expressed from TOC and nitrate concentrations showed high values for extreme flows and particularly for very low flow rates, generally in summer, where nitrate is assimilated by biomass. Considering TOC and nitrate fluxes, it is confirmed that the worst situations were encountered for very high flow rates, namely for TOC exportation during surface runoff which was related to heavy rains or floods. These findings are of great importance with regard to the adaptation for drinking water treatment in facing extreme hydrological conditions, of which the frequency is increasing with climate change.
ISSN: 0022-1694

hal-00878009
https://hal.archives-ouvertes.fr/hal-00878009
DOI : 10.1016/j.jhydrol.2012.11.006

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : While oceanic circulation in the Gulf of Lion (GoL) has often been studied in calm weather or with northerly winds (Tramontane or Mistral) through observations and numerical circulation models, few studies have focused on southeasterly storm events. Yet, correct representation of the circulation during storms is crucial if the suspension of sediments is to be correctly modelled throughout the Gulf. The purpose of this paper is to describe the hydrodynamics in the Gulf of Aigues-Mortes (NW of the GoL) during the storm of 18 February 2007 by using a set of data from an ADCP station placed at a depth of 65 m on the sea bed off the coast at Sète, supplemented by the ocean circulation model SYMPHONIE. This storm was characterized by a moderate south-easterly wind (15 m . s−1) and waves of up to 5 m of significant height at its apex. At the ADCP, strong currents of up to 0.8 m . s−1 near the surface and 0.5 m . s−1 near the bottom were recorded, parallel to the coast, flowing towards the south-west. The simulated currents were widely underestimated, even taking the effect of waves into account in the model. It was suspected that the representation of the wind in the atmospheric model was an underestimation. A new simulation was therefore run with an arbitrarily chosen stronger wind and its results were in much better agreement with the measurements. A simplified theoretical analysis successfully isolated the wind-induced processes, responsible for the strong currents measured during the apex and the strong vertical shear that occurred at the beginning of the storm. These processes were: 1/ the barotropic geostrophic current induced by a wind parallel to the coast and 2/ the Ekman spiral. The duration of the storm (about 36 h at the apex) explains the continuous increase of the current as predicted by the theory. The frictionally induced Ekman transport explains the current shear in the surface layer in the rising stage of the storm, and the addition of high waves and strong wind at the apex is more in favour of strong vertical mixing in the surface layer.
ISSN: 1631-0713

hal-00908200
https://hal.archives-ouvertes.fr/hal-00908200
DOI : 10.1016/j.crte.2013.07.001

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Despite a relatively 'uniform' fertile composition (Al2O3 = 2 center dot 19-4 center dot 47 wt %; Fo% = 89 center dot 2 +/- 0 center dot 3%; Cr#(Spl) = 8 center dot 9 +/- 1 center dot 5%), the Montferrier peridotite xenoliths show a wide range of S contents (22-590 ppm). Most sulphides are interstitial and show peculiar pyrrhotite-pentlandite intergrowths and low abundances of Cu-rich phases. Sulphide-rich samples are characterized by strong enrichment in the light rare earth elements and large ion lithophile elements without concomitant enrichment of the high field strength elements. Such trace-element fractionation is commonly ascribed to metasomatism by volatile-rich melts and/or carbonatitic melts. S and Se (11-67 ppb), as well as S/Se (up to approximate to 12 000), are correlated with La/Sm. Cu, however, remains broadly constant (30 +/- 5 ppm). These features strongly suggest that the percolation-reaction of such volatile-rich fluids has led to sulphide enrichment with an atypical signature marked by strong fractionation of the chalcophile elements (i.e. S vs Se and Cu). S-rich xenoliths are also characterized by high (Pd/Ir)(N) (1 center dot 2-1 center dot 9; where subscript N indicates normalized to chondrite), (Pd/Pt)(N) between 1 center dot 5 and 2 center dot 2, and (Os/Ir)(N) up to 1 center dot 85. Despite the relative uniform fertile composition of the xenoliths, Re/Os ranges between 0 center dot 02 and 0 center dot 18. Os-187/Os-188 is extremely variable even within a single sample and can be as high as 0 center dot 1756 for the most S-rich samples. Sulphides show highly fractionated and variable abundances of the highly siderophile elements (HSE) [0 center dot 03 (Pd/Ir)(N) < 1283] and Re-Os isotopic composition (0 center dot 115 < Os-187/Os-188 < 0 center dot 172). Such variation can be observed at the thin-section scale. Whole-rock and in situ sulphide data demonstrate that chalcophile and HSE systematics and the Os isotopic composition of the upper mantle could be significantly modified through metasomatism, even with volatile-rich fluids. These features highlight the complex behaviour of the HSE in fluid-rock percolation-reaction models and suggest a complex interplay between sulphide addition (crystallization or sulphidation) and partial equilibration of pre-existing sulphide. The specific fractionations observed in chemical proxies such as S and Se, Os and Ir, and Pd and Pt, as well as the low abundance of Cu-rich sulphides, suggest that sulphide addition may not have occurred via sulphide melts. Rather, we infer that S was present as a dissolved species in a (supercritical) oxidizing, volatile-rich fluid (C-O-H-S +/- Cl) along with other chalcophile and siderophile elements such as Os, Pd, Re and Au. The highly radiogenic Os composition of this fluid ( Os-187/ Os-188 > 0 center dot 17) would imply that such fluids are derived from an uncommon type of mantle source possibly related to carbonatite melts.
ISSN: 0022-3530

hal-00644524
https://hal.archives-ouvertes.fr/hal-00644524
DOI : 10.1093/petrology/egr038

Résumé : Sea fish farms with production of more than 20 tons per year in France must obtain two operating licences: (i) one for Sea Farming (AECM), with the aim of ensuring that the granted site and use of the maritime public domain for exploitation will respect all restrictions of general interest; (ii) one for regulating Facilities Classified for the Protection of the Environment (ICPE). Although the first one requires a relatively simple licence request file, the second one demands a very complete file, which includes, beyond the notice of exploitation information, a complete impact study, as well as a hazards study and a health and safety notice. In this context, petitioners in Corsica (adjustment of status or new exploitation) are faced with the same difficulties, which highlighted the need for a methodological guide adapted to each region's specific situation, assembling in particular the necessary baseline data (legal, zootechnical, geographical, climatic, socio-economic, ecological...) as well as recognised methods for evaluating the potential effects of the farm on the environment. Development of this guide was supported by ADEC and supervised by a steering committee composed of representatives from the administrations concerned, fish farmers and scientific bodies. The significant aspects dealt with the effects of fish farming on Posidonie herbarium, a protected species very present in Corsica and with coordinating the two AECM and ICPE procedures. For each part of the ICPE file, the guide introduces the technical or scientific context and, depending upon the case, the state of the art, sources of available data, acquisition and methods of acquiring measurements and of assessing the potential effects, as well as practical editing recommendations. Finally, the guide is made complete by a model schedule of conditions designed to help petitioners to have a specialist research department incorporate all or part of the file. This guide primarily concerns first-time marine facilities for exploitation in Corsica, conceived of as in the open sea rather than in confined spaces. Nonetheless, any fish farmer or future fish farmer needing to process a request for an exploitation licence may find it useful.
Les piscicultures marines de plus de 20 t/an de production sont soumises en France à l'obtention de deux autorisations d'exploiter : (i) celle au titre des Cultures Marines (AECM), visant à s'assurer que le site concédé et l'usage du domaine public maritime pour l'exploitation permettent de respecter l'ensemble des contraintes d'intérêt général ; (ii) celle au titre de la réglementation des Installations Classées pour la Protection de l'Environnement (ICPE). Si la première nécessite un dossier de demande d'autorisation relativement simple, la seconde requiert un dossier très complet, qui comprend, outre une notice de renseignements sur l'exploitation, une étude d'impact complète, ainsi qu'une étude des dangers et une notice d'hygiène et de sécurité. Dans ce contexte, les demandeurs en Corse (régularisation ou exploitation nouvelle) sont confrontés aux mêmes difficultés, ce qui a mis en évidence le besoin d'un guide méthodologique adapté aux spécificités régionales, rassemblant en particulier les données de base nécessaires (juridiques, zootechniques, géographiques, climatiques, socio-économiques, écologiques...) ainsi que les méthodes reconnues de l'évaluation des effets potentiels de la ferme sur l'environnement. L'élaboration de ce guide a été soutenue par l'ADEC et suivie par un comité de pilotage composé de représentants des administrations concernées, des pisciculteurs et d'organismes scientifiques. Les aspects importants ont porté sur les effets de la pisciculture sur l'herbier de Posidonie, espèce protégée très présente en Corse et sur la coordination entre les deux procédures AECM et ICPE. Pour chaque partie du dossier ICPE, le guide présente le contexte technique ou scientifique et selon le cas, l'état de l'art, les sources de données disponibles, les méthodes d'acquisition des mesures et d'évaluation des effets potentiels, ainsi que des recommandations pratiques de rédaction. Enfin, le guide est complété par un cahier des charges type destiné à aider les demandeurs à confier à un bureau d'étude spécialisé la réalisation de tout ou partie de la constitution du dossier. Ce guide concerne prioritairement les installations marines de nouvelles exploitations en Corse, envisagées en mer ouverte plutôt que dans des espaces confinés. Néanmoins tout pisciculteur ou futur pisciculteur devant instruire une demande d'autorisation d'exploiter peut y trouver intérêt.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2004/rapport-2188.pdf
http://archimer.ifremer.fr/doc/00000/2188/