203 research outputs found

    Cartographie AMT du biseau salé sur le flanc sud du Piton de la Fournaise (Ile de la Réunion)

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    Dans le secteur du Baril, situé sur la planÚze sud du volcan de la Fournaise, l'interprétation unidimensionnelle (1-D) de 34 sondages AMT montre une séquence à trois terrains, avec disparition du deuxiÚme dans la zone cÎtiÚre. Cette séquence comprend un horizon supérieur résistant (> 1000 Ohm.m), un horizon intermédiaire plus conducteur (100 à 600 Ohm.m), et un substratum trÚs conducteur (< 10 Ohm.m). Les résistivités obtenues permettent d'assimiler ce substratum au biseau salé. Les variations importantes dans la topographie du toit du biseau salé apportent des données nouvelles concernant les phénomÚnes de pénétration saline dans les aquifÚres volcaniques et, indirectement, une meilleure connaissance de la géométrie et du fonctionnement de l'aquifÚre sus-jacent. (Résumé d'auteur

    Impact of freshwater on a subarctic coastal ecosystem under seasonal sea ice (southeastern Hudson Bay, Canada) : 3. Feeding success of marine fish larvae

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    We monitored the feeding success (percent feeding incidence at length and mean feeding ratio at length) of Arctic cod (#Boreogadus saida) and sand lance (#Ammodytes sp. larvae in relation to prey density, light, temperature and potential predator density under the ice cover of southeastern Hudson Bay in the spring of 1988, 1989 and 1990. Both prey density and light limited larval fish feeding. The relationship between feeding success and actual food availability (nauplii density x irradiance) was adequately described by an Ivlev function which explained 64 and 76% of the variance in Arctic cod and sand lance feeding success respectively. By affecting both prey density and irradiance, the thickness of the Great Whale River plume (as defined by the depth of the 25 isohaline) was the main determinant of prey availability. Arctic cod and sand lance larvae stopped feeding when the depth of the 25 isohaline exceeded 9 m. Limitation of feeding success attributable to freshwater inputs occurred exclusively in 1988, the only time when the depth of the 25 isohaline exceeded the 9 m threshold. The close dependence of larval fish feeding success on the timing of the freshet and plume dynamics suggests a direct link between climate and survival of Arctic cod and sand lance larvae. The actual impact of climate fluctuations and/or hydro-electric developments on recruitment will depend on the fraction of the larval dispersal area of the two species that is affected by river plumes. (Résumé d'auteur

    Chronic wounds consultation by telemedicine between a rehabilitation healthcare center and nursing home or home

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    Saint-HĂ©lier Rehabilitation Center (pĂŽle MPR Saint-HĂ©lier), located in Rennes, has been selected for a regional telemedicine project in 2014 about chronic wounds.AimTo make care access easier for heavy disabilities patients in nursing homes or at home with chronic wounds.MethodThe members of TLM Pl@ies chronic team are specialist doctors and nurses for wounds. On request, the occupational therapist or dietician involve in the consultation (multidisciplinary approach). A secure videoconference (web) is used.ResultsSince July 2014, over 100 teleconsultations have been done. Targeted population is constituted by patients:– whose access to care is decreased due to moving difficulties;– of which the health care team is crossing difficulties in the care process (wound care but also disability, nutrition..).Seventy percent of requests come from the nursing home, 30% from homes (pressure ulcers stages 3 and 4, arterial ulcers, venous or mixed). Middle age: 78 years (20–101 years). Only 3 patients refused. Time to organize the teleconsultation is on average 13 days. Consultations last on average 25 minutes. In 30% of cases the teleconsultation is extended by a real live training time for the nurse at home guided by the TLM Pl@ies chroniques team. We evaluate professional satisfaction and technical satisfaction. Without teleconsultation, in 77% of cases transportation request for consultation would be made, in 5% hospitalization. In 18% no request would be done.Discussion/conclusionThese first results, encouraging, confirms the interest of specialized consultations in medico-social settings, and telemedicine can be an effective solution

    Debris avalanches on the western flank of Piton des Neiges shield volcano (Reunion Island)

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    Les faciĂšs brĂ©chiques reconnus Ă  terre dans la rĂ©gion littorale de Saint-Gilles, sur le flanc ouest du volcan Piton des Neiges, sont clairement identifiĂ©s comme des dĂ©pĂŽts d’avalanche de dĂ©bris. Leur Ă©tude pĂ©trographique, texturale et structurale permet de montrer, grĂące Ă  la prĂ©sence de coulĂ©es autochtones interstratifiĂ©es, qu’au moins quatre glissements successifs se sont produits. Le premier est de grande ampleur puisqu’il affecte la zone centrale hydrothermalisĂ©e du volcan. Il est proposĂ© que ce premier glissement, favorisĂ© par la prĂ©sence de matĂ©riaux ayant subi une importante altĂ©ration hydrothermale, crĂ©e une zone d’instabilitĂ© qui influe sur le comportement ultĂ©rieur du Piton des Neiges. Dans ce mĂȘme secteur, les glissements postĂ©rieurs concernent uniquement des domaines plus superficiels, mettant en jeu des matĂ©riaux non hydrothermalisĂ©s et vacuolaires. La brĂ©chification des formations, et en particulier la dĂ©sagrĂ©gation progressive des “blocs” durant le transport de l’avalanche de dĂ©bris, implique une vitesse de progression Ă©levĂ©e. Dans la zone du Cap La Houssaye, l’abrasion et la striation des formations laviques situĂ©es sous les unitĂ©s brĂ©chiques, ainsi que les phĂ©nomĂšnes de tassement observĂ©s, sont interprĂ©tĂ©s comme des figures d’arrĂȘt de l’avalanche
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