Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Introduction The Latitudinal Gradient Hypothesis (LGH) foresees that specialized metabolites are overexpressed under low latitudes, where organisms are subjected to higher herbivory pressure. The widespread macroalga Asparagopsis taxiformis is composed of six distinct genetic lineages, some of them being introduced in many regions. Objectives To study (i) metabolic fingerprints of the macroalga and (ii) its bioactivity in space and time, both as proxies of its investment in defensive traits, in order to assess links between bioactivities and metabotypes with macroalgal invasiveness. Methods 289 macroalgal individuals, from four tropical and three temperate regions, were analyzed using untargeted metabolomics and the standardized Microtox (R) assay. Results Metabotypes showed a low divergence between tropical and temperate populations, while bioactivities were higher in temperate populations. However, these phenotypes varied significantly in time, with a higher variability in tropical regions. Bioactivities were high and stable in temperate regions, whereas they were low and much variable in tropical regions. Although the introduced lineage two exhibited the highest bioactivities, this lineage could also present variable proliferation fates. Conclusion The metabolomic approach partly discriminates macroalgal populations from various geographic origins. The production of chemical defenses assessed by the bioactivity assay does not match the macroalgal genetic lineage and seems more driven by the environment. The higher content of chemical defenses in temperate versus tropical populations is not in accordance with the LGH and cannot be related to the invasiveness of the macroalgae.
ISSN: 1573-3882

hal-01681538
https://hal.archives-ouvertes.fr/hal-01681538
DOI : 10.1007/s11306-017-1169-z

Éditeur(s) : HAL CCSD Association de Géographes Français
Résumé : International audience
The international symposium on Urban Growth and Natural Hazards, in particular in Developing Countries was held in the Université Blaise-Pascal, Clermont-Ferrand (France) on December 2 and 3, 1994. This meeting brought together about 70 researchers, Ph. D. students, and professionals from France and 12 other countries, representing universities, research agencies, as well as government and private companies. The symposium aimed to gather specialists who are engaged and acting in programmes on hazard appraisal, risk prevention and urban management in the city environment. These people compared experiences acquired in two different fields: on the one hand urban growth and its consequences, and on the other hand, natural hazards and their effects, in particular in developing countries.From the 41 contributions given at the symposium, 4 papers were selected by the editorial board of this Bulletin de l'Association de Géographes Français for this special issue, which includes three chapters corresponding to the three sessions of the symposium: (1) Natural hazards and environmental factors : inventory, diagnostic and classification, (2) Vulnerability of urban society and environment : concepts, approaches, and classification, (3) Tools for urban risk prevention and risk management in case of crisis and catastrophes.
Ce numéro du Bulletin de l'Association de Géographes Français résume les résultats des tables rondes et de 41 contributions de chercheurs français et étrangers au colloque international «Croissance urbaine et risques naturels dans les pays en développement» qui s'est déroulé à l'Université Blaise-Pascal, Clermont-Ferrand, les 2 et 3 décembre 1994. L'objectif général du colloque était de rassembler les diverses compétences existant en France et à l'étranger dans le domaine de l'évaluation et de la gestion des risques naturels et de confronter les expériences acquises à l'interface entre les villes en croissance et le champ d'action des phénomènes naturels créateurs de risques. Le colloque a donc réuni des chercheurs, des doctorants et des praticiens de 12 pays, chargés de prévention, de gestion des risques naturels et de gestion urbaine, principalement dans les grandes villes des pays en développement (P.E.D.).Les contributions ont été regroupées, exposées et discutées lors du colloque sous forme de 3 thèmes : (1) Les phénomènes naturels créateurs de dommages (= menaces) : diagnostic, inventaire et typologie, (2) Les vulnérabilités des sociétés et des espaces urbanisés : concepts, typologie et modes d'analyse, (3) Les outils d'aide à la prévention et à la gestion du risque en milieu urbain. Certaines d'entre elles ont fait l'objet des quatre articles de ce Bulletin de l'Association de Géographes Français.
Colloque international : "Croissance urbaine et risques naturels dans les pays en développement"
Clermont-Ferrand, Université Blaise Pascal, France

ISBN : 0004-5322
hal-01165290
https://hal.archives-ouvertes.fr/hal-01165290

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Carbonation of peridotite is a widespread process in nature, with emerging societal and environmental implications through geological storage of CO2. We studied the micro- and nano-scale structures associated with the carbonation of peridotite pervaded by a CO2-rich water and the induced changes of its hydrodynamic properties. Focused ion beam (FIB) nanotomography was coupled with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations. An experimental sample of dunite core percolated by a CO2-rich fluid (pCO2 = 11 MPa) at 160 °C was compared with a naturally carbonated sample from the Atlantic Ridge (Exp. IODP 304). Results of the 8-days percolation experiment show continuous alteration of olivine into magnesite locally associated with a poorly crystalline serpentine-type mineral referred to as proto-serpentine. The experiment is also characterized by an overall decrease in rock porosity (from 7.7 to 6.4%) and permeability (from 8.5 × 10− 16 to 1.7 × 10− 16 m2). The primary inter-granular porosity (1 to 10 μm) is progressively filled with magnesite, leading to the overall decrease of permeability. At the same time, a secondary small-scale porosity (10 nm to 1 μm) is created at the tip of the dissolution features along the (010) cleavage planes of olivine grains. Carbonate crystals grow within these etch-pit structures behind the dissolution front. Dissolution and precipitation occur at a relative rate that maintains the secondary porosity over the timescale of the experiment (i.e. carbonate growth has to be the slowest one). This process is interpreted as an interface coupled dissolution-precipitation mechanism of olivine carbonation. Proto-serpentine is only formed in highly reduced flow areas, such as small olivine etch-pits (10 to 500 nm wide), which are more isolated from CO2 input. SEM-FIB analyses show the 3D preferential orientation of the dissolution-precipitation planes within a given olivine grain. It suggests the formation of lateral connections between the etch-pits (infra-micrometric “channels”) providing access to reactants and removing reaction products at the reaction sites. The experimental results show that olivine dissolution and magnesite precipitation converge to a quasi-steady state resulting in a constant carbonation rate controlled by reaction kinetics and not by mass transfer for this flow regime. The system self-regulates, independently of the porosity change at least during this incipient stage of olivine carbonation. Similar textures are observed in natural samples collected at 170 m-depth in the vicinity of veinlets driving late fluids down into the cooling oceanic lithosphere. This suggests that similar mechanisms are active in nature and can play an important role in the late, low temperature alteration stages of fractured peridotite. These results also highlight the critical role of nm-scale spatial arrangement of dissolution and precipitation features on mass transfers and on the sustainability of olivine carbonation through coupled dissolution-precipitation processes.
ISSN: 0009-2541

hal-01684733
https://hal.archives-ouvertes.fr/hal-01684733
DOI : 10.1016/j.chemgeo.2017.11.013

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
Estimations of zenith total delays (ZTD) were obtained during postprocessing of a high-resolution (2.4 km) nonhydrostatic atmospheric model (Méso-NH). These estimations were used to determine their sensitivity with respect to formulations of atmospheric refractivity, the approximation of zenith hydrostatic delays (ZHD) deduced from ground pressure, and the contributions of hydrometeors. The factor k for the conversion of zenith wet delay (ZWD) to integrated water vapor (IWV) was examined. Méso-NH is applied here to the extreme flash flood event of 8–9 September 2002 in southeastern France. The use of the hydrostatic formulation (to infer ZHD) leads to an overestimation of up to 18 mm with respect to the vertical integration of refractivity. Delay contributions of hydrometeors simulated by the high-resolution model reached more than 70 mm (%11 kg/m 2 IWV) in the heart of the convective cells in the case of the extreme flood event. The mean variations of IWV due to the use of different conversion factors (k used to transform ZWD to IWV) are evaluated to be less than 0.3 kg/m 2. This is less than the mean underestimation of IWV by 0.6 kg/m 2 relative to the GPS-like evaluation of IWV using the hydrostatic formulation and the ground temperature. In this study we also use GPS ZTD observations to validate three different numerical simulations of this extreme flood event. The simulation with the best fit to the GPS observations is also in best agreement with the surface rainfall measurements.
ISSN: 2169-897X

hal-01417608
https://hal.archives-ouvertes.fr/hal-01417608
https://hal.archives-ouvertes.fr/hal-01417608/document
https://hal.archives-ouvertes.fr/hal-01417608/file/Brenot_JGR_2006.pdf
DOI : 10.1029/2004JD005726

Éditeur(s) : HAL CCSD Sidestone Press
Résumé : International audience
Ce projet de prospection thématique avait pour objectif de comprendre l’utilisation du littoral du Grand Cul-de-Sac Marin de la Guadeloupe à la période coloniale et de mettre en évidence une typologie des structures littorales non militaires. Des prospections ont été réalisées sur 23 sites préalablement sélectionnés au cours de recherches documentaires (archives, cartes anciennes et documents géographiques contemporains). Le point de départ de cette réflexion sur l’occupation du territoire du Grand Cul-de-Sac est l’analyse de la carte des Ingénieurs du Roy de 1768 et de celles de la mission de Caspari et Ploix de 1868-1870.Ces prospections ont permis de mettre en évidence 12 sites répondant à la question des interfaces littorales. Après une présentation des méthodes et des résultats mis en oeuvre dans le cadre de ce projet, cette communication a pour objectif de présenter deux études de cas pour montrer différents types d’occupation de l’espace littoral dans le Grand Cul-de-Sac Marin.
Archéologie Caraïbe

Droits : info:eu-repo/semantics/OpenAccess
ISBN : 978-90-8890-291-8
hal-01480957
https://hal.archives-ouvertes.fr/hal-01480957
https://hal.archives-ouvertes.fr/hal-01480957/document
https://hal.archives-ouvertes.fr/hal-01480957/file/Guibert%20%26%20Bigot%202014%20-%20Entre%20terre%20et%20mer.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
In this paper, we introduce the Intuidoc-Loustic Gestures DataBase (ILGDB), a new publicly available database of realistic pen-based gestures for evaluation of recognition systems in pen-enabled interfaces. ILGDB was collected in a real world context and in an immersive environment. As it contains a large number of unconstrained user-defined gestures, ILGDB offers a unique diversity of content that is likely to serve as a precious tool for benchmarking of gesture recognition systems. We report first baseline experimental results on the task of Writer-Dependent gesture recognition.
ICPR2012 - 21st International Conference on Pattern Recognition
Tsukuba, Japan

hal-00802340
https://hal.inria.fr/hal-00802340
https://hal.inria.fr/hal-00802340/document

Éditeur(s) : HAL CCSD
Résumé : International audience
Cet ouvrage a pour objectif d'élargir l'interface entre la neurobiologie, les neurosciences cognitives et la didactique de la LV anglais oral. En ce sens, la neurodidactique n'est pas une nouvelle théorie de l'enseignement, mais une dynamique visant à adapter les pratiques pédagogiques à ce que l'on sait de manière concrète sur le fonctionnement du cerveau humain à ce jour. Les difficultés suscitées par la phonologie anglaise et le rapport phonie/graphie apparaissent bien souvent décourageantes dès le cycle 3. Pourtant, les neurobiologistes ont mis en évidence des éléments facilitateurs dans cet apprentissage, tels que l'importance de l'affect, du circuit de la récompense, des fonctions exécutives et de la résistance cognitive, du rôle du diagnostic et de l'erreur positive, de la démarche spiralaire et de la répétition, sans compter les interactions fondamentales en classe de langue et leur bénéfice sur la mémorisation à long terme. Les neurosciences en collaboration avec l'intelligence artificielle progressent à grands pas, et il serait regrettable que la didactique des langues ne profite pas également de ces avancées pour explorer la problématique délicate de l'anglais oral.
https://hal.archives-ouvertes.fr/hal-01626541

ISBN : 978-3-8417-3694-9
hal-01626541
https://hal.archives-ouvertes.fr/hal-01626541

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
This paper investigates the orientation and sources of stress in the forearc of the Cascadia subduction zone in southwest British Columbia, using Bayesian inversion results from focal mechanism data and comparing results with GPS derived short-term strain rates. The subduction margin in this region includes a change in orientation from N-S in Washington State to NW-SE in British Columbia. Over 1000 focal mechanisms from North American crustal earthquakes have been calculated to identify the dominant style of faulting, and ∼600 were inverted to estimate the principal stress orientations and the stress ratio. Our results indicate the maximum horizontal compressive stress orientation changes with distance to the trench, from approximately margin-normal along the coast to approximately margin-parallel 100-150 km inland from the coast. Comparing stress orientations with GPS data, we relate the margin-normal stress direction to subduction-related strain rates due to the locked interface between the North American and Juan de Fuca plates just west of Vancouver Island. Further from the margin the plates are coupled less strongly, and the margin-parallel maximum horizontal compressive stress in the North American Plate relates to the northward push of the Oregon Block, which is also observed in the horizontal shortening direction of the residual strain rates, after the subduction component is removed.
ISSN: 0148-0227

hal-00853734
https://hal.archives-ouvertes.fr/hal-00853734
DOI : 10.1029/2010JB008003

Éditeur(s) : HAL CCSD Elsevier
Résumé : Detailed sedimentological investigations on numerous outcrops and drill-core sections in the 2.1-Ga-old Franceville basin, Gabon, provide evidence for a large-scale injectite network. The injectites were formed by the injection of sands through a thickness of about 150 m of the FB1 Member, and now cover a minimum area of 70 km2 corresponding to the Bangombé plateau, but are also recognized close to Franceville 35 km farther south-east. The injectite lithology corresponds to a mud- or carbonate-supported sandstone characterized by a loose and uncompacted fabric contrasting with the host-rock. Because the injectites are often parallel to subparallel to the stratification, they were misinterpreted as depositional beds by previous authors. At outcrop, the injectite bodies exhibit sill, dyke, wing and protrusive geometries emplaced during early burial within poorly compacted material, with partial wall erosion and dissociation. The source of the sand material is attributed to a channel-levee turbidite depositional system located in the lower part of the FB1 Member. These deposits were buried by a thick biochemical muddy cap deposited during a starvation phase, which increased the seal capacity of the system. This type of architecture has a high potential to develop compaction disequilibrium during burial. Moreover, in the case of the Francevillian injectites, the abundance of microbial organic matter favoured early methane degassing and lateral charging of the sand reservoir. The overpressure in the channels was periodically released during early burial, through the effect of rapid sedimentary and tectonic loading, and possible seismic activity. The fluidized sand was injected according to a symmetrical wing pattern. Thus, the injected masses caused a local decrease in the grade of the lateritic manganese ore deposit of the Bangombé plateau.
ISSN: 0301-9268

hal-01667217
https://hal.archives-ouvertes.fr/hal-01667217
DOI : 10.1016/j.precamres.2017.09.022

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We present GravProcess, a set of MATLAB routines to process gravity data from complex campaign surveys and calculate the associated gravity field. Data reduction, analysis, and representation are done using the MATLAB Graphical User Interface Tool, which can be installed on most systems and platforms. Data processing is divided into several steps: (1) Integration of gravity data, station location, and gravity line connection input files; (2) Gravity data reduction applying solid-Earth tide and instrumental drift corrections and, depending on the required processing level, air pressure and oceanic tidal corrections; (3) Automatic network adjustment and alignment to absolute base stations; (4) Free air and terrain corrections to calculate gravity values and anomalies, and to estimate the associated errors. The final step is dedicated to post-processing and includes graphical representations of data and an output text file, which can be used by Geographic Information System software. An example of this processing chain applied to a recent survey in northern Morocco is given and compared with previous available results.
ISSN: 0098-3004

hal-01217120
https://hal.archives-ouvertes.fr/hal-01217120
DOI : 10.1016/j.cageo.2015.04.005

Éditeur(s) : HAL CCSD Coastal Education and Research Foundation
Résumé : Nearshore bars are generally present on sandy coasts and play a significant role in wave breaking and sediment exchange between beach and shoreface. The study area is located on the Languedoc-Roussillon coast in the Gulf of Lions (southern part of the French Mediterranean coast). This microtidal environment is classified as a wave-dominated coast. The sand coast displays different bar systems (single or multiple; straight or crescentic). The alongshore variability of bar morphology in the nearshore zone was investigated in August 2009 during one week, using a topo-bathymetric LIDAR data set (300 km(2)). LIDAR makes it possible to cover a large area in a very short time with a high resolution. The topo-bathymetric LIDAR offers the added benefit of morphological information about the beach-sea transition in very shallow water (below I in), data often difficult if not impossible to obtain with traditional techniques. The purpose of this paper is 1) to depict the distribution of bars and their characteristics along the 180 km coast of the Gulf of Lions; 2) to update the classifications of sand bars typologies in Languedoc-Roussillon; 3) to pay particular attention to the description of the intricate inner system. Globally, cross-shore distribution of subtidal morphologies is characterized by both an outer and an inner system. The outer system is crescent-shaped in the south and straight in the northern part with a distinctive regional delimitation. The inner system comprises an inner bar and, near the coast, a complex fluctuating bar called Low Bar Beach (LBB). Several intermediate states were identified and added to the new classification proposed in this paper. These results clearly emphasize the importance of LIDAR technology for a better understanding of bar behaviour and single and/or multi-bar beach organisation.
ISSN: 0749-0208

hal-00783187
https://hal.archives-ouvertes.fr/hal-00783187

Éditeur(s) : HAL CCSD
Résumé : National audience
A l'aire des stratégies d'accès aux traitements antirétroviraux mondialisées, la question des inégalités territoriales, questionne leur mise en place. Si les PVVIH sont particulièrement fragiles face aux violences structurelles, sociales et économiques, leur prise en charge aux frontières est souvent oubliée. Ce travail entend donc mettre en exergue une analyse de l'impact des frontières sur les PVVIH en Guyane mais aussi d'interroger de nouveaux modèles de pratiques médicales d'interface. En Guyane française, les configurations territoriales génèrent une situation singulière dans la mesure où les populations gravitent/évoluent entre une instabilité géographique (barrages policiers routiers et fluviaux, nomadisme et mobilité des populations) et des logiques d'intégration. De là, apparaît, un renforcement des vulnérabilités (psychologique, socio-économique, sanitaire, spatiale, (…) etc.), notamment chez les PVVIH. Afin d'améliorer la prise en charge de ces patients un relais avancé a été mis en place au sein du centre de santé à la frontière avec le Brésil à S t Gorges de l'Oyapock. Des médiateurs communautaires en santé sont au centre du dispositif avec les soignants du dispensaire local et un système de délocalisation des examens biologiques et avis spécialisés a été réalisé. En un an la file active de PVVIH suivis a été multipliée par 4. Cette action a permis de diminuer les délais de prise en charge des patients, réduisant également le nombre de perdus de vus. Il a été rendus possible pour exemple une prise en charge « familiale » du dépistage et des traitements impossible jusqu'à alors. Sur le plan médico-social des « staffs » transfrontaliers ont réalisés améliorant la gestion des patients dans leur globalité. Cet exemple de coopération inter-culturelle renforcée avec valorisation de l'espace comme carrefour géographique de différents flux migratoires que constitue la frontière Franco-Brésilienne fait de cet espace un lieu privilégié de médiation médicale.
Congrès 2016 de la Société française de lutte contre le sida
Montpellier, France

inserm-01475951
http://www.hal.inserm.fr/inserm-01475951
http://www.hal.inserm.fr/inserm-01475951/document
http://www.hal.inserm.fr/inserm-01475951/file/2016%2C%20Mosnier%20-%20Fronti%C3%A8res%20%20limites%20ou%20espaces%20innovants%20dans%20la%20lutte%20contre%20le%20VIH.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The lower Pleistocene Kritika Member of the Rhodes Formation is composed of predominantly siliciclastic deposits that are sometimes intercalated with hardbottoms formed by drowning of former beachrock beds. A wide variety of sclerobionts occur in this environment, very different from the poorest soft‐bottom populations occurring in other levels of the Kritika Member. The most characteristic, abundant and frequently diverse are the encrusting forms: coralline algae, bivalves, serpulid worms, and bryozoans. Numerous other groups of sessile and vagile organisms are associated with these crust‐forming communities. A number of skeletal organisms (sometimes including zooxanthellate coral colonies) formed small carbonate buildups on top of several beachrock beds. Boring organisms also occur. Evidence for a two‐step deepening succession over the previously formed beachrock is provided by palaeontological and sedimentological data. The rapidly cemented sandy‐conglomeratic beds were first colonised by a relatively shallow‐water (around 20 m) biocoenosis of mostly encrusting organisms. Another association, with encrusting and erect organisms, was later established in a deeper environment (20-40 m). A comparison with Holocene beachrock occurring on the coast of Rhodes was also undertaken. Their submerged part provided habitat for poorer but similar biotas to those occurring in the Kritika Member. The lower Pleistocene beachrock and associated organogenic fossil assemblages indicate repeated drowning episodes during deposition of the Kritika Member and provide help in sequence stratigraphic interpretations of these siliciclastic deposits. Notably, they can be used as indicators of relative sea‐level changes.
ISSN: 0031-0182

hal-00795591
https://hal.archives-ouvertes.fr/hal-00795591
DOI : 10.1016/j.palaeo.2012.09.007