Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Tethyan ophiolites show an apparent poorly organized association of ultramafic andmafic rocks. By contrast tothe complete mantle-crustal sections of Semail-type ophiolite sheets, Tethyan ophiolites are characterized by asmaller amount of mafic rocks (gabbros and basalts), by the absence of any sheeted dyke complex and by thefrequent occurrence of oceanic sediments stratigraphically overlying mantle-derived peridotites and associatedgabbroic intrusions. Therefore, they are considered as typical remnants of oceanic lithosphere formed in slowspreadingenvironment or in ocean–continent transition at distal passive margins. In the very first models offormation of the Tethyan ophiolites, in the years 1980, the geodynamical processes leading to mantle unroofingwere poorly understood due to the paucity of data and concepts available at that time from the present-dayoceans. In particular, at that time, little work had focused on the distribution, origin and significance ofmafic rocks with respect to the dominant surrounding ultramafics. Here, we reconsider the geology of sometypical metaophiolites from the Western Alps and Corsica, and we show how results from the past decadeobtained in the current oceans ask for reassessing the significance of the Tethyan ophiolites in general. Revisitedexamples include a set of representative metaophiolites from the blueschists units of the Western Alps (Queyrasregion) and from Alpine Corsica (Golo Valley). Field relationships between the ophiolitic basement andthe metasedimentary/metavolcanic oceanic cover are described, outlining a typical character of the Tethyanophiolite lithological associations. Jurassic marbles and polymictic ophiolite metabreccias are unconformablyoverlying the mantle-gabbo basement, in a way strictly similar to what is observed in the non-metamorphicAppennine ophiolites or Chenaillet massif. This confirms that very early tectonic juxtaposition of ultramafic andmafic rocks occurred in the oceanic domain before subduction. This juxtaposition resulted from tectonic activitythat is now assigned to the development of detachment faults and to the formation of Oceanic Core Complexes(OCCs) at the axis of slow spreading ridges. This fundamental Plate Tectonics process is responsible for the exhumationand for the axial denudation of mantle rocks and gabbros at diverging plate boundaries. In addition, fieldrelationships between the discontinuous basaltic formations and the ultramafic–mafic basement indicate that thistectonic stage is followed or not by a volcanic stage.We discuss this issue in the light of available field constraints.
ISSN: 0012-8252

insu-01096467
https://hal-insu.archives-ouvertes.fr/insu-01096467
https://hal-insu.archives-ouvertes.fr/insu-01096467/document
https://hal-insu.archives-ouvertes.fr/insu-01096467/file/Lagabrielle-EarthSciRev-2014.pdf
DOI : 10.1016/j.earscirev.2014.11.004

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Experimental modelling applied to the study of orogenic wedge dynamics has been a subject of fruitful research for more than 30 years, although the technique dates back as far as the early XIXth century. On one hand, several first order parameters controlling the structural evolution of mountain belts have been intensively investigated using the classic tectonic "sandbox" models. The main parameters are the properties of the basal décollement, the deforming material, the backstop, and fluxes, kinematics and surface processes. On the other hand, the morphological evolution of a mountain relief subjected to changing tectonic or climatic forcing has been addressed using another kind of approach called "geomorphic" models. Nowadays, the literature is extremely rich, particularly for the sandbox technique, so that it becomes difficult to have an exhaustive view of the effects of the above parameters on mountain evolution. In this article, we propose a detailed review of the main results obtained using both "tectonic" and "geomorphic" approaches. Our goal is to provide an almost complete state-of-the-art in the experimental study of relief dynamics to guide present and future researchers in their understanding of mountain belt evolution.
ISSN: 0040-1951

hal-00757713
https://hal.archives-ouvertes.fr/hal-00757713
DOI : 10.1016/j.tecto.2012.01.027

Éditeur(s) : HAL CCSD Seismological Society of America
Résumé : International audience
We present an improvement of the maximum intersection (MAXI) method in which absolute earthquake location is defined by the maximum intersection number of hyperbolic equal differential time (EDT) volumes (one EDT volume being described as all grid nodes satisfying the arrival‐time differences between two stations, ± a tolerance value known as TERR). This 3D technique is well adapted to a strongly heterogeneous environment, avoids the depth versus origin‐time trade‐off (even using P arrivals alone), and objectively filters possible erroneous arrival times. Improvements consist of introducing an iterative multiscale approach on the TERR parameter and conducting a hierarchy of grid discretization to refine the preliminary solution (multigrid algorithm). The outlier cleaning process is strengthened by conducting statistical analyses based on the number of EDT volume intersections per station, rather than on travel‐time residues. Processing two series of synthetic arrival times computed in the 3D seismological configuration of the southernmost Ryukyu subduction zone, offshore Taiwan, allows us to (1) confirm MAXI robustness, even when arrival times are highly disturbed or azimuthal coverage largely reduced, and (2) show that MAXI, by limiting trade‐offs between origin time and depth and between epicentral position and depth, is less affected by a wrong velocity model than a technique that minimizes travel‐time residues. To conclude, we apply the MAXI method to locate earthquakes recorded by the combined Central Weather Bureau of Taiwan (CWB) and the Japanese Meteorological Agency (JMA) networks (1991-2008) within a georealistic a priori 3D P‐velocity model. Hypocenter determinations are selected based on MAXI confidence factors, and earthquake clustering along well‐known tectonic features witnesses hypocenter determination accuracy.
ISSN: 0037-1106

hal-00725227
https://hal.archives-ouvertes.fr/hal-00725227
DOI : 10.1785/0120100311

Éditeur(s) : HAL CCSD European Geosciences Union
Résumé : International audience
Earth deformation is a multi-scale process ranging from seconds (seismic deformation) to millions of years (tectonic deformation). Bridging short- and long-term deformation and developing seismotectonic models has been a challenge in experimental tectonics for more than a century. Since the formulation of Reid's elastic rebound theory 100 years ago, laboratory mechanical models combining frictional and elastic elements have been used to study the dynamics of earthquakes. In the last decade, with the advent of high-resolution monitoring techniques and new rock analogue materials, laboratory earthquake experiments have evolved from simple spring-slider models to scaled analogue models. This evolution was accomplished by advances in seismology and geodesy along with relatively frequent occurrences of large earthquakes in the past decade. This coincidence has significantly increased the quality and quantity of relevant observations in nature and triggered a new understanding of earthquake dynamics. We review here the developments in analogue earthquake modelling with a focus on those seismotectonic scale models that are directly comparable to observational data on short to long timescales. We lay out the basics of analogue modelling, namely scaling, materials and monitoring, as applied in seismotectonic modelling. An overview of applications highlights the contributions of analogue earthquake models in bridging timescales of observations including earthquake statistics, rupture dynamics, ground motion, and seismic-cycle deformation up to seismotectonic evolution.
ISSN: 1869-9510

hal-01553120
https://hal.archives-ouvertes.fr/hal-01553120
https://hal.archives-ouvertes.fr/hal-01553120/document
https://hal.archives-ouvertes.fr/hal-01553120/file/rosenau2017.pdf
DOI : 10.5194/se-8-597-2017

Éditeur(s) : Université Nice Sophia Antipolis
Résumé : The Lesser Antilles is a case study of a very slow subduction (~2 cm/yr) of an old oceanic lithosphere (~84-100 Ma). The region presents a relatively low seismic activity, especially along the interplate contact, and the seismic hazard associated with a possible mega-thrust earthquake is still poorly known. This PhD thesis is a first step toward assessing the ability of the Lesser Antilles subduction zone to produce such a large subduction event. To do so, it aims at constraining the downdip width of the interplate's seismogenic zone. The lack of coverage of permanent seismological stations is a major limitation in the exploration of the Lesser Antilles subduction zone. It is due to the presence of only small aligned islands at far distances from the potentially seismogenic interplate area. Several oceanographic cruises were therefore planned that notably allowed the repeated deployment of ocean bottom seismometers; some of them being left for a few months of background seismicity recording. This thesis specifically focuses on two sets of wide-angle seismic data acquired offshore the Dominica and Martinique islands. From their analysis 3D and 2D tomographic models were produced respectively over the forearc region and across the whole subduction complex. These models constrain the plates' seismic structure as well as their geometry. They allow the discussion of how the imaged structures affect the subduction processes and give a first estimation of the downdip width of the seimogenic zone, defined as the segment of the interplate between the backstop and the upper plate's Moho. The joint interpretation of seismic models and earthquake localizations then refine this first assessment. Epicenter distribution from height months of seismic recording shows indeed that seismicity concentrates within the inner forearc region. The strong velocity gradient that characterize its basement suggests it is denser and more rigid than the more deformable outer forearc basement. The updip limit of the seismogenic zone could then lie arcward of the backstop at the contact of the interplate and the seaward end of the inner forearc crust. At depth, interplate earthquake mechanisms are observed between 35 and 45 km depth and interpreted to have occurred at the downdip limit of the seismogenic zone. The latter could reach a depth over 10,km deeper than the contact of the upper plate's Moho with the interplate, and therefore lie within the mantle wedge. All together, these results imply a large downdip width of the seismogenic zone (~70 km) offshore the Dominica and Martinique islands. Further work is, however, needed in order to fully comprehend the ability of the Lesser Antilles subduction zone to produce a possible mega-thrust earthquake. This would necessitate the evaluation of seismic coupling at the interplate contact and the possible segmentation of the seismogenic zone, for instance, due to the subduction of oceanic ridges.
Les Petites Antilles présentent un contexte géodynamique caractérisé par la subduction à très faible vitesse (~2 cm/an) d'une lithosphère océanique âgée (~84-100 Ma). L'activité sismique y est relativement faible, notamment à l'interplaque, où l'aléa sismique lié à un éventuel séisme de méga-chevauchement reste encore mal contraint. Cette thèse se veut être une première étape dans l'évaluation de la capacité de la zone de subduction des Petites Antilles à générer un tel évènement. Dans ce but, ces travaux tentent d'appréhender l'extension en profondeur du domaine sismogène de l'interplaque. Le manque de couverture des stations sismologiques permanentes est un inconvénient majeur dans l'exploration des Petites Antilles. Il s'explique en raison du peu de terres émergées et de leur éloignement de la zone potentiellement sismogène de l’interplaque. La région a donc fait l'objet de plusieurs campagnes océanographiques qui ont permis, notamment, le déploiement de sismomètres fond de mer (OBS); certains instruments étant restés immergés plusieurs mois afin de procéder à une écoute de la sismicité. Les travaux réalisés au cours de cette thèse se sont focalisés sur deux jeux de données de sismique grand-angle acquis au large des îles de la Dominique et de la Martinique. Leur analyse a permis la construction de modèles tomographiques 3D et 2D respectivement à l'échelle de l'avant-arc et de l'ensemble de la subduction. Ces modèles renseignent sur la structure sismique des plaques en convergence ainsi que sur leur géométrie. Ils permettent de discuter le rôle de la structure dans le fonctionnement de la subduction et d’obtenir une première estimation de l'extension en profondeur de la zone sismogène en considérant la portion de l'interplaque comprise entre le butoir et le Moho de la plaque supérieure. Dans un second temps, l'interprétation conjointe des modèles tomographiques et des localisations des séismes locaux a permis d'affiner cette estimation. Huit mois d'enregistrement de la sismicité montrent en effet une concentration des épicentres dans la région interne de l’avant-arc. Celle-ci présente un socle épais, à fort gradient de vitesse interprété comme plus dense et rigide que le socle de la région externe de l'avant-arc, plus déformable. La limite amont de la zone sismogène pourrait donc se situer en retrait de la position du butoir au contact de l'interplaque et de la limite entre ces deux zones de l'avant-arc. En profondeur, des mécanismes interplaques sont observés entre 35 et 45 km et interprétés comme des marqueurs de la limite aval de la zone sismogène. Cette dernière pourrait donc atteindre une profondeur jusqu'à 10 km supérieure à la limite précédemment évoquée et se trouver, par conséquent, au contact du manteau lithosphérique. L'ensemble de ces résultats suggèrent une extension en profondeur de la zone sismogène (i.e une largeur) de près de 70 km face aux îles de la Dominique et de la Martinique. Ces travaux doivent cependant être poursuivis afin d’évaluer pleinement la capacité de la zone de subduction des Petites Antilles à générer un éventuel séisme de méga-chevauchement. Le taux de couplage à l'interplaque doit être précisé ainsi que sa possible segmentation en lien, par exemple, avec à l'entrée en subduction des rides océaniques.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00172/28335/26628.pdf
http://archimer.ifremer.fr/doc/00172/28335/

Éditeur(s) : HAL CCSD
Résumé : International audience
The Duffy Antigen/Receptor for Chemokine (DARC) is a seven segment transmembrane protein. It was firstly discovered as a blood group antigen and was the first specific gene locus assigned to a specific autosome in man. It became more famous as an erythrocyte receptor for malaria parasites (Plasmodium vivax and Plasmodium knowlesi), and finally for chemokines. DARC is an unorthodox chemokine receptor as (i) it binds chemokines of both CC and CXC classes and (ii) it lacks the Asp-Arg-Tyr consensus motif in its second cytoplasmic loop hence cannot couple to G proteins and activate their signaling pathways. DARC had also been associated to cancer progression, numerous inflammatory diseases, and possibly to AIDS. In this review, we will summarize important biological data on DARC. Then we shall focus on recent development of the elaboration and analyzes of structural models of DARC. We underline the difficulty to propose pertinent structural models of transmembrane protein using comparative modeling process, and other dedicated approaches as the Protein Blocks. The chosen structural models encompass most of the biochemical data known to date. Finally, we present recent development of protein - protein docking between DARC structural models and CXCL-8 structures. We propose a hierarchal search based on separated rigid and flexible docking.
Infectious disorders drug targets

Droits : info:eu-repo/semantics/OpenAccess
inserm-00366309
http://www.hal.inserm.fr/inserm-00366309
http://www.hal.inserm.fr/inserm-00366309/document
http://www.hal.inserm.fr/inserm-00366309/file/de_Brevern_Autin_Bertrand_Colin_Etchebest.pdf
http://www.hal.inserm.fr/inserm-00366309/file/inserm-00366309_edited.pdf

Résumé : En 2013, Le Groupe d'experts Intergouvernemental sur l'Evolution du Climat (GIEC) publie son cinquième rapport concernant les changements climatiques. Il y est souligné que le réchauffement climatique est sans équivoque, et que de nouvelles émissions de gaz à effet de serre impliqueront une poursuite du réchauffement et des changements affectant toutes les composantes du système climatique. En région tropicale, une hausse de la température, ainsi qu'une intensification des événements de sécheresse et de pluviométrie extrêmes sont à prévoir. C'est dans ce contexte que s'inscrit ce travail, dont le but est d'étudier la réponse de la forêt tropicale à ces changements climatiques prédits en Guyane Française. Pour ce faire, j'ai utilisé les données du dispositif de suivi forestier de Paracou pour construire un modèle de dynamique individuel basé sur les traits fonctionnels des arbres. Un modèle de mortalité a d'abord été réalisé puis couplé à un modèle de croissance.Le modèle couplé ainsi construit permet de modéliser la croissance et la mortalité des arbres sur un pas de temps de 2 ans tout en tenant compte de leur ontogénie et de leurs traits fonctionnels. Ce modèle a d'abord été appliqué aux essences commerciales de Guyane Française en forêt naturelle et exploitée en y ajoutant un indice de stress hydrique. Ceci permet de montrer que le stress hydrique fait baisser la croissance et augmenter la mortalité, tandis que l'exploitation a l'effet inverse. Malgré le signal commun, différentes réponses sont observées selon les espèces. Le modèle a ensuite été appliqué à la communauté en forêt naturelle pour identifier les drivers climatiques et les processus impactés. Il ressort que la croissance est impactée par le stress hydrique et la température, et que la mortalité est impactée par le stress hydrique et la pluviométrie totale.Ces résultats ont enfin permis de construire un modèle complet de dynamique forestière climat dépendant, et de simuler l'évolution d'une communauté pendant un siècle selon différents scénarios correspondant aux prédictions du GIEC. Les simulations mettent en évidence une très forte diminution de la croissance, ainsi qu'une plus faible diminution de la mortalité. Ceci entraine une diminution notable de la surface terrière, du diamètre quadratique et de la biomasse fraiche. Une analyse de sensibilité montre que ces changements sont principalement dus à l'augmentation sévère des températures prédites pour le siècle à venir. Des pistes de réflexion sur les enjeux de modélisation et les échelles considérées sont proposées en discussion de ce travail.
In 2013 the intergovernmental panel on climate change (ipcc) publishes its fifth report. This report underlines that an increase of temperature and a strengthening of drought and extreme rainfall are expected in tropical regions. This work was made in this context of climate changes, and aimed to study the response of the rainforest to predicted climate changes. To do this, i used the data from the study site of Paracou French Guiana to build an individual based dynamics model based on the functional traits of trees. This model was first applied to species with a commercial interest in French Guiana, in natural and logged forest and adding a water stress index as predictor. Water stress decreases growth and increases mortality, while logging had the opposite effect. The model was then applied to the community in natural forest for identifying potential climate drivers and impacted processes. Growth is impacted by the water stress and temperature and mortality is imp acted by the water stress and the total rainfall. These results allowed us to build a climate dependent model of forest dynamics and to run simulations of the evolution of a community under different scenarios for the next century. Simulations showed a decrease of growth and a small decrease of mortality. This resulted in a substantial decrease of basal area, squared diameter and fresh biomass.

http://www.theses.fr/2014AGUY0802/document

Éditeur(s) : HAL CCSD Springer International Publishing
Résumé : The intensive farming practices that have been developed over the past 60 years are based mainly on the use of chemical inputs such as fertilisers and pesticides, mechanical tillage and monoculture. The limitations of these methods are now clear: long-term degradation of soil fertility, impacts on the environment and human health, high consumption of fossil fuels, low efficiency of inputs and threats to food security in a context of climate change. Would farming practices that rely on the activation of ecological processes be an alternative to achieve a balance between high productivity and environmental preservation? While many studies suggest a positive relationship between soil biodiversity and ecosystem services, there is considerable debate on the form such agricultural systems should take. This study reviewed the state of current knowledge and identified aspects requiring further research to achieve the aim of sustainable intensification of agriculture. The following major points emerged: 1) Most studies focused on the evaluation of individual practices. However, changes in farmers’ cropping practices to take advantage of soil biodiversity services would need to manage not only the interactions between various practices but also the trade-off between the technical and socio economic constraints of cropping systems. Advances in agricultural system design approaches may help to ensure appropriate trade-offs. 2) More attention should be given to drawing on knowledge from different sources: laboratory studies focusing on the ecological functions of soil biodiversity, experimental surveys on farmers’ fields to rank the farming practices and processes to be included in site-specific models, and on- station experiments to test hypotheses and acquire additional reference material. 3) Whereas advances in technical and scientific knowledge provide an increasing number of relevant indicators for characterizing biodiversity and ecological functions, studies are rarely targeted at the development of indicators that are accessible to farmers or their technical advisors. The lack of indicators accessible to grassroots players for evaluating the impacts of their decisions on soil biodiversity remains a serious obstacle to the development of innovative agro-ecological systems.
Sustainable Agriculture Reviews 14

ISBN : 978-3-319-06015-6
hal-01268743
https://hal.archives-ouvertes.fr/hal-01268743
DOI : 10.1007/978-3-319-06016-3_5
PRODINRA : 270786

Éditeur(s) : HAL CCSD Presses Universitaires de Louvain (distribution I6DOC/CIACO)
Résumé : In French. 10 pages, 5 figures, LaTeX 2e using EPSF and custom package taln2006.sty (designed by Pierre Zweigenbaum, ATALA). Proceedings of the 13th annual French-speaking conference on Natural Language Processing: `Traitement Automatique des Langues Naturelles' (TALN 2006), Louvain (Leuven), Belgium, 10-13 April 2003
National audience
We propose a theoretical framework within which information on the vocabulary of a given corpus can be inferred on the basis of statistical information gathered on that corpus. Inferences can be made on the categories of the words in the vocabulary, and on their syntactical properties within particular languages. Based on the same statistical data, it is possible to build matrices of syntagmatic similarity (bigram transition matrices) or paradigmatic similarity (probability for any pair of words to share common contexts). When clustered with respect to their syntagmatic similarity, words tend to group into sublanguage vocabularies, and when clustered with respect to their paradigmatic similarity, into syntactic or semantic classes. Experiments have explored the first of these two possibilities. Their results are interpreted in the frame of a Markov chain modelling of the corpus' generative processe(s): we show that the results of a spectral analysis of the transition matrix can be interpreted as probability distributions of words within clusters. This method yields a soft clustering of the vocabulary into sublanguages which contribute to the generation of heterogeneous corpora. As an application, we show how multilingual texts can be visually segmented into linguistically homogeneous segments. Our method is specifically useful in the case of related languages which happened to be mixed in corpora.
Verbum ex machina : Actes de la 13ème conférence annuelle sur le Traitement Automatique des Langues Naturelles
Louvain (Leuven), Belgium

hal-00327607
https://hal.archives-ouvertes.fr/hal-00327607
ARXIV : 0810.1212

Éditeur(s) : HAL CCSD Universidad de Malaga
Résumé : International audience
The development of information systems follows a long and complex process in which various actors are involved. We report an experiment in which we observe the evolution of the analysis model of an information system through 15 successive versions. We use indicators on the underlying concept lattices built by applying Relational Concept Analysis (RCA) to each version. RCA is an extension of FCA which groups entities based on characteristics they share, including links to other entities. It here helps in analyzing their evolution. From this experience, we establish recommendations to monitor and verify the proper evolution of the analysis process.
CLA'2012: 9th International Conference on Concept Lattices and Applications
Fuengirola (Málaga), Spain

ISBN : 978-84-695-5252-0
lirmm-00743886
http://hal-lirmm.ccsd.cnrs.fr/lirmm-00743886
http://hal-lirmm.ccsd.cnrs.fr/lirmm-00743886/document

Éditeur(s) : Elsevier
Résumé : Bioaccumulation is difficult to document because responses differ among chemical compounds, with environmental conditions, and physiological processes characteristic of each species. We use a mechanistic model, based on the Dynamic Energy Budget (DEB) theory, to take into account this complexity and study factors impacting accumulation of organic pollutants in fish through ontogeny. The bioaccumulation model proposed is a comprehensive approach that relates evolution of hake PCB contamination to physiological information about the fish, such as diet, metabolism, reserve and reproduction status. The species studied is the European hake (Merluccius merluccius, L. 1758). The model is applied to study the total concentration and the lipid normalised concentration of 4 PCB congeners in male and female hakes from the Gulf of Lions (NW Mediterranean sea) and the Bay of Biscay (NE Atlantic ocean). Outputs of the model compare consistently to measurements over the life span of fish. Simulation results clearly demonstrate the relative effects of food contamination, growth and reproduction on the PCB bioaccumulation in hake. The same species living in different habitats and exposed to different PCB prey concentrations exhibit marked difference in the body accumulation of PCBs. At the adult stage, female hakes have a lower PCB concentration compared to males for a given length. We successfully simulated these sex-specific PCB concentrations by considering two mechanisms: a higher energy allocation to growth for females and a transfer of PCBs from the female to its eggs when allocating lipids from reserve to eggs. Finally, by its mechanistic description of physiological processes, the model is relevant for other species and sets the stage for a mechanistic understanding of toxicity and ecological effects of organic contaminants in marine organisms.
Journal of Sea Research (1385-1101) (Elsevier), 2009-10 , Vol. 62 , N. 2-3 , P. 124-134

Droits : 2009 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2009/publication-6789.pdf
DOI:10.1016/j.seares.2009.02.006
http://archimer.ifremer.fr/doc/00000/6789/

Éditeur(s) : HAL CCSD
Résumé : The evolution of mountain belt piedmont is controlled by interactions between tectonics, erosion and sedimentation. To study coupling between these processes, we analyze morphometric data collected in the eastern Tian Shan piedmont (NW China) and develop a new analogue modelling technique. The modeling approach uses an experimental set-up and analog material specifically designed to study simultaneously tectonic structures (faults, folds), detailed morphology (drainage basins, channels, alluvial fans, etc.) and stratified sedimentation. Measurement techniques based on laser interferometry and image correlation are also developed to quantify the topographic and kinematic evolution of models.
Our experiments allow a new approach for the study of piedmont morphotectonic evolution. Our results indicate that tectonics mainly controls this evolution. The propagation of deformation and the formation of relief both significantly influence the development of drainage networks, the evolution of drainage basins and the formation of morphotectonic markers. Particularly, a study of alluvial fans and watershed metrics suggests that there is a dynamical equilibrium between uplift, erosion and morphology. In addition, our results show that terrace nucleation is controlled by thrust activity and hydrography adjustments. Folding of terraces responds to a homothetic deformation pattern.
This new methodology brings promising perspectives in the fields of geomorphology, seismotectonics and sedimentology.
L'évolution d'un piémont de chaîne de montagnes est contrôlée par les interactions entre la tectonique, l'érosion et la sédimentation. Pour étudier ces processus, nous avons analysé des données morphométriques issues des piémonts orientaux du Tian Shan (NW Chine) et développé un nouveau type de modélisation analogique. Cette approche utilise un dispositif et un matériau expérimental spécialement conçus pour modéliser simultanément des structures tectoniques (failles, plis), une morphologie détaillée (bassins versants, rivières, cônes alluviaux, etc.) et une sédimentation stratifiée. Des techniques de mesure optique ont été également mises en oeuvre afin de quantifier l'évolution topographique et cinématique des modèles.
Les expériences réalisées offrent une opportunité inédite d'étudier l'évolution morphotectonique d'un piémont. Nos résultats montrent que la tectonique exerce un contrôle de premier ordre sur cette évolution. La propagation de la déformation et la formation des reliefs influencent en effet significativement le développement du réseau de drainage, l'évolution des bassins versants et la formation des marqueurs morphotectoniques. En particulier, l'analyse de la morphométrie des cônes alluviaux et de leurs bassins versants suggère qu'un équilibre dynamique s'installe entre la surrection, l'érosion et la morphologie. Nos résultats montrent également que l'apparition des terrasses est guidée par l'activité des chevauchements et les adaptations de l'hydrographie. Leur modèle de plissement répond à une déformation homothétique.
Cette nouvelle approche ouvre des perspectives d'étude prometteuses en géomorphologie, sismotectonique et stratigraphie.
https://tel.archives-ouvertes.fr/tel-00339145

tel-00339145
https://tel.archives-ouvertes.fr/tel-00339145
https://tel.archives-ouvertes.fr/tel-00339145v2/document
https://tel.archives-ouvertes.fr/tel-00339145/file/These_Graveleau08.pdf

Éditeur(s) : HAL CCSD
Résumé : Among erosion processes, river incision is classicaly described as a key process controlling erosion of landscapes. Incision efficiency is mainly influenced by climate and erodibility. This latter is not only dependent on the nature of the bedrock, but also on its past deformation, which affects its rheological effective properties, such as fracture density. The main objectives of this thesis are: (1) to better constrain the relationship between effective properties and erodibility, and (2) to quantify the influence of erodibility and erosion on both the temporal and spatial building or decay of the topography. Several numerical tools are developed. A 1D formalism of landscape evolution is introduced, including river incision with stochastic distribution of water discharge and hillslope landsliding. A new remeshing algorithm called Surface Lagrangian Remeshing (SLR) is developed as a complement to remeshing algorithms dealing with internal elements. It allows one to take into account long-term erosion into 2D Lagrangian numerical codes based on triangular finite elements. Then the potentiality of measuring erodibility in-situ using a Schmidt hammer (R) is assessed for the active orogen of Taiwan, the diagenetic Annot sandstones and St Clement fault zone. Results suggest a strong control of R by effective properties. A linear model based on effective medium theory is applied to a fault zone with an unmacthed resolution (750 measures, 25 measures per square meter). The model successfully correlates R to fracture density. These results demonstrate that effective elasticity as well as erodibility are sensitive to the density and type of fractures. Finally I focus on the erosional and rheological conditions that allows reproducing post-orogenic evolution of mountain belts. A model coupling surface erosion and regional isostatic uplift is consistent with observations. The topographic decay and decrease of the ratio of surface elevation over crustal root thickness is at first order controlled by the initial geometry of the mountain belt and erosion efficiency. This new model highlights the control ofclimate and erodibility on the topographic decay and of lithospheric rheology on the perseverance of crustal roots.
Parmi les processus d'érosion, l'incision des rivières est classiquement décrit comme un processus clé contrôlant l'érosion des paysages. L'efficacité de l'incision est principalement influencée par le climat et par l'érodabilité. Ce dernier paramètre ne dépend pas seulement de la nature du substratum rocheux, mais aussi de sa déformation passée qui affecte ses propriétés rhéologiques équivalentes. Les principaux objectifs de cette thèse sont: (1) de mieux contraindre les relations entre propriétés équivalentes et érodabilité, et (2) de quantifier l'influence de l'érosion et de l'érodabilité sur la formation ou la décadence, spatiale et temporelle, de la topographie. Plusieurs outils numériques sont développés. Un formalisme 1D d'évolution des paysages est proposé, prenant en compte simultanément l'incision des rivières avec une distribution stochastique des débits en eau et l'érosion des versants par glissements de terrain. Un nouvel algorithme de remaillage appelé Surface Lagrangian Remeshing (SLR) est développé. Il permet de prendre en compte l'érosion à long terme dans les codes numériques 2D Lagrangiens basés sur des éléments finis triangulaires. Ensuite, la possibilité de mesurer in-situ l'érodabilité avec un marteau de Schmidt (R) est évaluée pour: l'orogène actif de Taiwan, les grès diagénétiques d'Annot et la zone de faille de St Clément. Les résultats suggèrent un fort contrôle de R par les propriétés équivalentes des roches testées. Un modèle linéaire, basé sur la théorie des milieux équivalents, est appliqué à une zone de faille avec une résolution inégalée (750 mesures, 25 mesures par mètre carré). Le modèle permet de corréler avec succès la densité de fracture et R. Ces résultats démontrent empiriquement que l'élasticité équivalente ainsi que l'érodabilité sont sensibles à la densité et à la nature des fractures. Enfin j'étudie les conditions d'érosion et de rhéologie qui permettent de reproduire l'évolution des chaînes de montagnes post-orogéniques. Un modèle couplant érosion en surface et soulèvement isostatique régional est compatible avec les observations. Les taux de décroissance topographique et de diminution du rapport de l'élévation de surface sur l'épaisseur de racine crustale sont contrôlés au premier ordre par la géométrie initiale de la chaîne de montagne et par l'efficacité de l'érosion. Ce nouveau modèle met en évidence le contrôle du climat et de l'érodabilité sur la décroissance topographique et de la rhéologie lithosphérique sur la persévérance des racines crustales.
https://tel.archives-ouvertes.fr/tel-00602341

tel-00602341
https://tel.archives-ouvertes.fr/tel-00602341
https://tel.archives-ouvertes.fr/tel-00602341/document
https://tel.archives-ouvertes.fr/tel-00602341/file/thesephilippesteer.pdf

Éditeur(s) : HAL CCSD
Résumé : Guadeloupe Island (West French Indies) is one of the twenty islands that compose the Lesser Antilles Arc, which results from the subduction of the Atlantic Ocean plate beneath the Caribbean one. The island lies in a complex volcano-tectonic system and the need to understand its geological context has led to numerous on- and offshore geophysical investigations. This work presents the compilation and processing of available, on-land, airborne and marine, gravity and magnetic data acquired during the last 40 years on Guadeloupe Islands and at the scale of the Lesser Antilles Arc. The overall dataset provides new Bouguer and reduced to the pole magnetic anomaly maps at the highest achievable resolution. Regionally, the main central negative gravity trend of the arc allows defining two subsident areas. The first one is parallel to the arc direction (~N160°E) to the north, whereas the second unexpected southern one is oriented parallel to oceanic ridges (N130°E). Along the Outer Arc, the long wavelength positive anomaly is interpreted, at least along the Karukera Spur, as an up-rise of the volcanic basement in agreement with the seismic studies. To the NE of Guadeloupe, the detailed analysis of the geophysical anomalies outlines a series of structural discontinuities consistent with the main bathymetric morphologies, and in continuity of the main fault systems already reported in this area. Based on geophysical evidences, this large scale deformation and faulting of the Outer Arc presumably primarily affects the Atlantic subducting plate and secondarily deforms the upper Caribbean plate and the accretion prism. At the scale of Guadeloupe Island, joined gravity and magnetic modeling has been initiated based on existing interpretation of old seismic refraction profiles, with a general structure in three main layers. According to our geophysical anomalies, additional local structures are also modeled in agreement with geological observations: i) the gravity and magnetic signals confirm an up-rise of the volcanic basement below the limestone platforms outcropping on Grande-Terre Island ; ii) the ancient volcanic complexes of Basse-Terre Island are modeled with high density and reverse magnetized formations; iii) the recent volcanic centre is associated with formations consistent with the low measured density and the underlying hydrothermal system. The EW models coherently image a NNW-SSE depression structure in half-graben beneath Basse-Terre Island, its western scarp following the arc direction in agreement with bathymetric and seismic studies to the north of the island. The so-defined depressed area, and particularly its opening in half-graben toward the SW, is interpreted as the present-day front of deformation of the upper plate associated with the recent volcanic activity on and around Guadeloupe. Based on this regional deformation model, perspectives are given for further integrated investigation of key targets to address the internal structure and evolution of the Lesser Antilles Arc and Guadeloupe volcanic system.
Colloque 2012 du Comité National Français de Géodésie et Géophysique (CNFGG)
Clermont-Ferrand, France

hal-00742653
https://hal-brgm.archives-ouvertes.fr/hal-00742653
https://hal-brgm.archives-ouvertes.fr/hal-00742653/document
https://hal-brgm.archives-ouvertes.fr/hal-00742653/file/CNFGG_Caraibes.pdf

Éditeur(s) : Wiley-blackwell
Résumé : 1. Approximately 300 pelagic fish species naturally aggregate around floating objects (FOBs) at the surface of the oceans. Currently, more than 50% of the world catch of tropical tuna comes from the industrial tuna fisheries around drifting FOBs. Greater understanding of the complex decision-making processes leading to this aggregation pattern and the impact of the massive release of artificial FOBs by fishermen on the spatial distribution and management of tuna is needed. 2. We analyse how the interplay between social (relationships between individuals) and non-social (responses to the environment) behaviours may affect the spatial distribution of a population in a multi-FOB environment. Taking the example of tropical tunas associating with FOBs and using differential equations and stochastic simulations, we examine how, when increasing the number of FOBs, fish aggregation dynamics and the distribution of the population among patches are affected by the population size, level of sociality and the natural retentive and/or attractive forces of FOBs on individual tuna. 3. Our model predicts that, depending on the species' level of sociality, fish will be scattered among FOBs or aggregated around a single FOB based on the number of FOBs deployed in a homogeneous oceanic region. 4. For social species, we demonstrated that the total fish catch is reduced with increasing FOBs number. Indeed, for each size of population, there are a number of FOBs minimizing the total population of fish associated with FOBs and another number of FOBs maximizing the total population of associated fish. 5. Synthesis and applications. In terms of fisheries management, the total catch volume is directly linked to the total number of floating objects (FOBs) for non-social species, and any limit on the number of sets would then result in a limit on the total catch. For social species (e.g. tuna), however, increasing the number of FOBs does not necessarily lead to an increase in the total catch, which is a non-intuitive result. Indeed, our model shows that, for specific values of the parameters, deploying a greater number of FOBs in the water (all other parameters being constant) does not necessarily help fishermen to catch more tuna, but does increase the level of fishing effort and bycatch.
Journal Of Applied Ecology (0021-8901) (Wiley-blackwell), 2013-10 , Vol. 50 , N. 5 , P. 1081-1092

Droits : 2013 The Authors. Journal of Applied Ecology, 2013 British Ecological Society
http://archimer.ifremer.fr/doc/00151/26275/24439.pdf
DOI:10.1111/1365-2664.12140
http://archimer.ifremer.fr/doc/00151/26275/

Éditeur(s) : HAL CCSD Springer
Résumé : International audience
In science learning, context is an important dimension of any scientific object or phenomenon, and context-dependent variations prove to be as critical for deep understanding as are abstract concepts, laws and rules. The hypothesis presented is that a context gap between two students can be illuminating to highlight the respective general-particular aspects of an object or phenomenon. Furthermore, provoking a perturbation during the learning process to obtain the emergence of such an event could be a productive tutoring strategy. The authors introduce the emergence of context effects as a problem space, to be modeled in the system, and propose a model of the contextual dimension (MazCalc) associated with an analytical view of its modeling, based on a metaphor in physics. A Learning Scenario (Gounouy) has been designed and tested with two groups of learners in Guadeloupe and in Quebec, and MazCalc has been instantiated for this pilot study. Finally, an architecture of a Context-Aware Intelligent Tutoring System is presented, with services to learners, teachers and researchers.
Context in Computing

ISBN : 978-1-4939-1886-7
hal-01536054
https://hal.univ-antilles.fr/hal-01536054
DOI : 10.1007/978-1-4939-1887-4_17

Éditeur(s) : Université de la Polynésie Française
Résumé : The ontogeny of osmoregulation was studied in the blue shrimp Litopenaeus stylirostris in New Caledonia. The implication of branchial organs in ionic regulation was first demonstrated in juveniles by immunolocalization of three ion transporting proteins ( namely NKA, co-transporter NKCC1 and CFTR ) and ionocyte detection was done by means of electron microscopy. The role of the main ion transporting enzyme, NKA, was subsequently investigated during post-embryonic development using an integrative approach associating physiological, histological, immunological and biomolecular studies. Results obtained allowed us to propose a model of the osmoregulatory pattern in L. stylirostris based on weak regulation in the early stages, then progressively this species acquires the adult pattern of hyper-hypo-regulation after metamorphosis with the concurrent development of epipodites and gills. Strong NKA immunofluorescence and abundance of NKA transcripts in these two tissues compared to others organs suggest their functional implication in osmoregulatory processes. The results of this study allow us to increase our knowledge of the penaeid shrimp osmoregulation and to propose zootechnical measures to improve the animal physiological comfort. These propositions have been already tested during larval rearing trials, leading a two-fold-growth in 19 days-old postlarvae.
L’étude de l’ontogenèse de l’osmorégulation a été entreprise chez la crevette bleue Litopenaeus stylirostris en Nouvelle-Calédonie. L’implication des tissus de la cavité branchiale dans la régulation ionique a été déterminée au préalable chez des juvéniles par immunolocalisation de trois transporteurs protéiques d’ions, ( la NKA, le co-transporteur NKCC1 et le CFTR ) et par la détection de ionocytes en microscopie électronique. Le rôle de la NKA a été particulièrement étudié et son implication a été examinée au cours du développement post-embryonnaire par une approche intégrative associant des études physiologiques, histologiques, immunologiques et moléculaires. Cette démarche nous a permis de proposer un modèle d’osmorégulation chez L. stylirostris: de faible régulatrice dans les premiers jours de sa vie, cette espèce évolue vers l’hyper-hypo-régulation après la métamorphose avec le développement progressif des épipodites et des branchies. L’immunofluorescence prononcée de la NKA ainsi que l’abondance des transcrits du gène codant la NKA dans les tissus de ces deux organes suggèrent leur implication fonctionnelle dans l’ionorégulation. Les résultats de ce travail nous ont permis d’accroître nos connaissances sur l’osmorégulation chez les pénéidés et de proposer des améliorations zootechniques visant à augmenter leur confort physiologique. Ces préconisations ont fait l’objet de premiers essais en conditions d’élevage et se sont traduites par un doublement de la croissance des post-larves de 19 jours.

Droits : 2011 The author, Univ. Polynésie Française
http://archimer.ifremer.fr/doc/00052/16314/13816.pdf
http://archimer.ifremer.fr/doc/00052/16314/

Éditeur(s) : HAL CCSD ATALA (Association pour le Traitement Automatique des Langues)
Résumé : In French. 10 pages, 4 figures, LaTeX 2e using EPSF and custom package Taln2003.sty (JC/PZ, ATALA). Proceedings of the 10th annual French-speaking conference on Natural Language Processing: `Traitement Automatique des Langues Naturelles' (TALN 2003), Batz-sur-mer, France, 10-14 June 2003
National audience
In this article, some first elements of a computational modelling of the grammar of the Martiniquese French Creole dialect are presented. The sources of inspiration for the modelling is the functional description given by Damoiseau (1984), and Pinalie's & Bernabe's (1999) grammar manual. Based on earlier works in text generation (Vaillant, 1997), a unification grammar formalism, namely Tree Adjoining Grammars (TAG), and a modelling of lexical functional categories based on syntactic and semantic properties, are used to implement a grammar of Martiniquese Creole which is used in a prototype of text generation system. One of the main applications of the system could be its use as a tool software supporting the task of learning Creole as a second language.
Nous présenterons dans cette communication les premiers travaux de modélisation informatique d'une grammaire de la langue créole martiniquaise, en nous inspirant des descriptions fonctionnelles de Damoiseau (1984) ainsi que du manuel de Pinalie & Bernabé (1999). Prenant appui sur des travaux antérieurs en génération de texte (Vaillant, 1997), nous utilisons un formalisme de grammaires d'unification, les grammaires d'adjonction d'arbres (TAG d'après l'acronyme anglais), ainsi qu'une modélisation de catégories lexicales fonctionnelles à base syntaxico-sémantique, pour mettre en oeuvre une grammaire du créole martiniquais utilisable dans une maquette de système de génération automatique. L'un des intérêts principaux de ce système pourrait être son utilisation comme logiciel outil pour l'aide à l'apprentissage du créole en tant que langue seconde.
TALN 2003 : Actes de la 10ème conférence annuelle sur le Traitement Automatique des Langues Naturelles
Batz-sur-mer, France

hal-00327553
https://hal.archives-ouvertes.fr/hal-00327553
ARXIV : 0810.1199

Éditeur(s) : HAL CCSD
Résumé : This study is designed to improve the understanding of structural, mechanical and petrophysical characteristics of deformation bands in porous sandstone such as their potential influence on fluid storage or migration in reservoir setting. Structural and petrophysical analysis of band networks from Provence show that permeability of band is mainly controlled by the degree of cataclasis and diagenetic processes at depth. Map-scale analysis of band networks underlines the major influence of tectonic regime on band distribution, organization and permeability. Band associated to normal-fault regime (cataclasis and low-permeability) are located around map-sclae-fault whereas band associated to thurst-fault regime (moderate cataclasis and permeability) are pervasively distributed in all the area. Reverse-sense band are cataclastic and low-permeabiilty around the Roquemaure thrust, which show the potential role of large-scale fault on structural and petrophysical characteristics of bands. This analysis also shows the influence of fault propagation on formation of low permeability catacastic bands. This analysis suggests also granulometry as factor controlling organization of band networks.A mechanical analysis of deformation bands is realized based on results from Provence. Yield envelopes of these materials are calculated from analytical solution. Triaxial tests done on sandstone (L'Etang quarry, Orange) confirm the shape of yield envelope theoretically calculated. Triaxial tests done on the poorly-lithified sands (Boncavaï quarry, Uchaux) show grain size, sorting and packing influencing yield envelope and cataclastic band localization at shallow burial depth. Stress paths are calculated for burial and tectonic event (extension and contraction) using the relationship between main stress and secondary stresses (K0) calibrated from well data. These different results are integrated into a model which allows to estimate type and structural characteristics of bands susceptible to form for a known geological setting.A structural, mechanical and petrophysical model is established form these results. This model is calibrated by permeability data from deformation bands of Provence and results from the mechanical model of strain localization. This model is also confronted to a synthesis of permeability data from literature, which confirms the influence of the different controlling parameters integrated to the model. This model is applied for two sites of uranium exploration/exploitation in porous sandstone reservoirs and validated by field observations.
Cette étude est destinée à améliorer la compréhension des caractéristiques structurales, pétrophysiques et mécaniques des bandes de déformation dans les grès poreux ainsi que de leur rôle potentiel sur la migration ou le piégeage des fluides en milieu réservoir. L'analyse structurale et pétrophysique des réseaux de bandes de Provence montre que leur perméabilité découle principalement de l'intensité de la cataclase dans leur microstructure et des processus diagénétiques qui peuvent s'y localiser avec la profondeur. L'analyse régionale de ces réseaux de bandes souligne l'influence majeure du régime tectonique sur leur distribution, leur organisation et leur perméabilité. Les bandes associées au régime normal (cataclactiques et peu perméables) sont localisées autour des failles cartographiques, tandis que les bandes associées au régime inverse (modérement cataclastiques et perméables) sont distribuées dans toute la région. Les bandes inverses sont fortement cataclastiques et imperméables uniquement autour du chevauchement de Roquemaure ce qui montre le rôle potentiel de la présence de grande faille sur les caractéristiques structurales et pétrophysiques de ces bandes. D'autre part, cette analyse suggère que la granulométrie de l'encaissant peut influencer l'initiation et l'organisation des réseaux. L'analyse mécanique des bandes de déformation a ensuite été réalisée à partir des résultats obtenus en Provence. L'enveloppe de plasticité de ces matériaux est calculée à l'aide d'une solution analytique. Les essais triaxiaux menés sur le grès de la carrière de l'Etang (orange) confirment la forme de ces enveloppes estimées théoriquement. Les essais réalisés sur les sables de Boncavaï (Uchaux) montrent que la taille des grains, le tri et de la compaction dans ces matériaux peu lithifiés influent sur leurs enveloppes de plasticité et la localisation des bandes cataclastiques à faibles profondeurs. Les trajets de contraintes sont estimés pour les phases d'enfouissement et de chargement tectonique (extension et compression) à partir de la relation entre contrainte principale et contraintes secondaires (K0), calibrée à partir de données de forage. Ces résultats sont intégrés à un modèle permettant d'estimer la nature et les caractéristiques structurales des bandes susceptibles de se former dans un contexte géologique donné. Un modèle structural, mécanique et pétrophysique a été établir à partir de ces différents résultats. Ce modèle est calibré à partir des données de perméabilité mesurées sur les bandes de Provence et des résultats du modèle mécanique de localisation cité précédemment. Ce modèle a ensuite été confronté à une synthèse des données de perméabilité disponibles dans la littérature et confirme l'influence des différents paramètres de contrôle pris en compte dans le modèle. Ce modèle a enfin pu être appliqué sur deux sites d'explorations/exploitations d'uranium en réservoir gréseux poreux et validé par les résultats obtenus, en concordance avec les observations de terrain.
https://tel.archives-ouvertes.fr/tel-01001389

NNT : 2013MON20067
tel-01001389
https://tel.archives-ouvertes.fr/tel-01001389
https://tel.archives-ouvertes.fr/tel-01001389/document
https://tel.archives-ouvertes.fr/tel-01001389/file/36072_BALLAS_2013_archivage-1_cor.pdf

Éditeur(s) : HAL CCSD Springer
Résumé : International audience
Thiswork examines the relevance of the inclusion of ground-based gravity data in the calibration process of a global rainfall-discharge reservoir model. The analysis is performed for the Durzon karst system (Larzac, France). The first part of the study focuses on the hydrological interpretation of the ground-based gravity measurements. The second part of the study investigates further the information content of the gravity data with respect to water storage dynamics modelling.The gravity-derived information is found unable to either reduce equifinality of the single-objective, dischargebased model calibration process or enhance model performance through assimilation.
ISSN: 1866-6280

hal-00812624
https://hal-brgm.archives-ouvertes.fr/hal-00812624
DOI : 10.1007/s12665-012-1856-z