Éditeur(s) : American Geophysical Union
Résumé : As part of the French CLIPPER project, an eddy permitting model of the Atlantic circulation has been run for 22 years. The domain has open boundaries at Drake passage and at 30 degreesE, from Africa to Antarctica. The simulated mean circulation, as well as the eddy activity, is satisfactory for a 1/3 degrees model resolution, and the meridional heat transport at 30 degreesS is within the range estimated from observations. We use the "mixed" open boundary algorithm of Barnier et al. [1998], which has both a radiation condition and a relaxation to climatology. The climatological boundary forcing strongly constrains the solution in the whole domain. The model heat balance adjusts through the surface (heat flux retroaction term) more than the open boundaries. The radiation phase velocities calculated within the algorithm are analyzed. This shows, quite surprisingly, that both the eastern and western boundaries have a similar behavior, regardless of the preferred directions for advection (mainly eastward) and wave propagation (mainly westward). Our results confirm that open boundary algorithms behave differently according to the dynamics of the region considered. The passive boundary condition that Penduff et al. [2000] applied successfully in the north eastern Atlantic does not work in the present South Atlantic model. We emphasize the need for a careful prescription of the climatology at the open boundary, for which a new approach based on synoptic sections is implemented.
Journal of Geophysical Union - Research C - Oceans (0148-0227) (American Geophysical Union), 2001-10 , Vol. 106 , N. C10 , P. 22115-22129

Droits : 2001 American Geophysical Union
http://archimer.ifremer.fr/doc/2001/publication-454.pdf
DOI:10.1029/2000JC000376
http://archimer.ifremer.fr/doc/00000/454/

Éditeur(s) : Soc Francaise D Ichtyologie
Résumé : The ichtyofauna of Geyser and Zelee coral banks (north of Mozambique canal) was investigated in 1996, this work being the first quantitative study on this area. Quantitative data were collected on 11 stations (mean depth 18 m) by visual observations along 50 m transect, widened to 2 m for small sedentary species, and to 5 m for commercial species with a large action range. The main descriptors of the fish communities (species richness, abundance per species) and the trophic structure (omnivorous, herbivorous, carnivorous, browsers of sessile invertebrates) were described and analysed.A total of 294 fish species, belonging to 43 families were recorded. The species richness varied from 45 to 83 species / station, and the abundance, from 292 to 1322 individuals / 100 m(2), the lower values being recorded on the inner slope and the higher ones on the outer slope. In terms of number of individuals, diurnal planktivores were highly represented at all sites (mean 63.7%). Pomacentridae and Caesionidae were the most abundant families, damselfishes being mainly represented by Chromis ternatensis (mean 73 ind., max, 148 ind. 100 m(2)), C. dimidiata (mean 33 ind., max. 151 ind. / 100 m(2)) and Dascyllus carneus (mean 38 ind., max. 92 ind. 100 m(2)), and fusiliers by Pterocaesio chrysozona (mean 19 ind., max. 128 ind. / 100 m(2)), P. tile (mean 12 ind., max. 38 ind. / 100 m(2)) and Caesio teres (mean 6 ind., max. 32 ind. / 100 m(2)). The high values recorded showed that small and isolated coral banks can support relatively rich fish faunas and substantial populations of individuals. This result may be explained by different factors such as the oceanographic circulation favourable to a localised enrichment of nutrients from surface water, the low human impact, a good coral cover and a high degree of self-recruitment associated with regional recruitment. Nevertheless, the main commercial species such as Lutjanus bohar and Variola louti, observed at each station, were represented at a low density (mean 0.8 ind., max. 6 ind. / 100 m(2) and mean 0.2 ind., max. 0.8 ind. / 100 m(2) respectively). This result may be due to the exploitation of these coral banks between 1990 and 1992, which was interrupted following the fast decreasing output.Such an experience shows us the fragility of these small coral banks and the necessity to establish a rational management of the resource.
Cybium (0399-0974) (Soc Francaise D Ichtyologie), 2002 , Vol. 26 , N. 1 , P. 11-26

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00000/10132/7687.pdf
http://archimer.ifremer.fr/doc/00000/10132/

Éditeur(s) : HAL CCSD
Résumé : International audience
This work aims to better understand the physical processes governing the wave propagation in a vertically shearedcurrent and the resulting nearshore circulation patterns. It is based on a high resolution hydro-morphodynamic fieldcampaign, ROUSTY2014, collecting a comprehensive hydro-morphodynamical dataset during a full winter season.The overall analysis highlights three main circulation patterns, largely controled by the bathymetric features and byco-working or competing wind and waves forcings. Regarding the vertical structuration of the circulation, most of fieldobservations shown seaward directed circulation with onshore component close to the air/sea surface whose intensityvaries according to incoming wave conditions. Forth, vertical shear increase when breaking happen close to sensorlocation and orientation of mean circulation depend on wind direction.
35th International Conference on Coastal Engineering
Antalya, Turkey

hal-01426582
https://hal.archives-ouvertes.fr/hal-01426582

Éditeur(s) : Taylor & Francis Ltd
Résumé : A new benthic phototrophic dinoflagellate is described from sediments of a tropical marine cove at Martinique Island and its micromorphology is studied by means of light and electron microscopy. The cell contains small golden-brown chloroplasts and the oval nucleus is posterior. It is laterally compressed, almost circular in shape when viewed laterally. It consists of a small epitheca tilted toward the right lateral side and a larger hypotheca. In the left view, the cingulum is more anterior and the epitheca is reduced. The cingulum is displaced and left-handed. This organism is peculiar in having no apical pore and its thecal plate arrangement is 2 ' 1a 7 '' 5c 3s 5 ''' 1 ''''. The plates are smooth with small groups of pores scattered on their surface. An area with 60-80 densely arranged pores is found near the centre of the 2 ''' plate, on the left lateral side. Morphologically, these features are different from all other laterally compressed benthic genera. In addition, molecular genetic sequences of SSU and partial LSU form a distinct and well-supported clade among dinoflagellates and support the erection of a new genus. However, molecular phylogenies inferred from ribosomal genes failed to confirm any clear relationship with other benthic taxa and affinity with other laterally compressed dinoflagellates has not been demonstrated. Hence, the taxonomic affinity of Madanidinium loirii with a defined order and family is unclear at the moment.
European Journal Of Phycology (0967-0262) (Taylor & Francis Ltd), 2014-04 , Vol. 49 , N. 2 , P. 165-178

Droits : 2014 British Phycological Society
http://archimer.ifremer.fr/doc/00195/30622/29458.pdf
DOI:10.1080/09670262.2014.898797
http://archimer.ifremer.fr/doc/00195/30622/

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : For Norwegians the name of our country is based on a route - "the way to the North" - and this was not a built route but using of the coast-line itself. As long as the boats and ships were the main means of travel this coastal way - "Nor-way" - was the main communication basis for most people, and for transport of goods. But even in the interior of the country, water, namely rivers and lakes were the main structures for communication. The lakes were most efficient for transport during the cold winters, by sledges on the frozen surfaces.When new means of transport took over most of the traffic, however, sea, lakes and rivers in many ways became obstacles instead of means of communication (?). This gave the government and others new challenges. In the sailing period up to the end of the eighteen hundreds, boats and harbors were the investment focus and sailors were recruited in every community from the age of 15. This meant that in a remote area at the Arctic Circle there were plenty of people who have been sailing around most of the work and could easily be hosts of visitors.This paper is mostly focusing on "how to market and develop these beautiful coastal areas to travelers using either their own cars, bikes, boats or collective transport". What types of geographical units are suited for marketing and developing such areas and how might local producers of accommodation, food & beverages, crafts, activities and arts be included in such organizations. The main focus will be on the work of organization "Kystriksvegen Reiseliv AS" that have been working with these challenges for closed to two decades. What have their successes and obstacles been and how have they been able to operate a sustainable business on a long coastal route with many car ferries, small islands, fjords and mountains and more than twenty municipalities.
Pour les Norvégiens, le nom de notre pays est basé sur un itinéraire - «le chemin vers le Nord» - et ce n'était pas une route construite, mais qui repose sur la ligne de côte elle-même. Tant que les bateaux et les navires étaient le principal moyen de déplacement de cette façon côtière – "Nor-way" - était la base principale de communication pour la plupart des gens et pour le transport de marchandises, et même à l'intérieur du pays, l'eau, à savoir les rivières et les lacs étaient les principales structures de communication. Les lacs sont les plus efficaces pour le transport pendant les hivers froids, par traîneaux sur les surfaces gelées.Avec l’arrivée des nouveaux moyens de transport, la mer, les lacs et les rivières à bien des égards, sont devenus obstacles (?). Cela a donné de nouveaux défis au gouvernement. A l’époque de la voile jusqu'à la fin des dix-huit centaines, des bateaux et des ports ont été l'objet d'investissements et les marins ont été recrutés dans toutes les collectivités dès l’âge de 15 ans. Cela signifie que dans une région éloignée dans le cercle arctique, il y avait beaucoup de gens qui étaient navigateurs et pouvaient facilement être les hôtes de visiteurs.Ce document est principalement axé sur «la façon de commercialiser et de développer ces belles régions côtières de voyageurs qui utilisent soit leurs propres voitures, motos, bateaux ou de transports collectifs». Quels types d'unités géographiques sont adaptés pour la commercialisation et le développement de ces régions ? Comment les producteurs locaux d'hébergement, de nourriture et de boissons, d’artisanat, les activités et les arts sont inclus dans ces organisations ? L'accent principal sera mis sur le travail de l’organisation "Reiseliv AS Kystriksvegen" qui a travaillé sur ces défis de fermeture depuis deux décennies. Quelles ont été leurs réussites et obstacles, et comment ont-ils pu exploiter une entreprise durable sur une longue route côtière avec des car-ferries, de nombreuses petites îles, des fjords et des montagnes et plus d’une vingtaine de municipalités.
Norvège

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.5286
http://journals.openedition.org/etudescaribeennes/5286

Résumé : Ce travail est l'expression d'une volonté de chercheurs, de la Carabe d'améliorer les connaissances scientifiques méso- et micro-météorologiques appliquées aux milieux insulaires sous influence des alizés et de développer la recherche dans ces domaines.On sait que le phénomène météorologique le plus remarquable impactant les îles de la Caraïbe reste le cyclone tropical. Mais d'autres phénomènes, a des échelles inferieures, telles que les pluies intenses, les houles, la dégradation de la qualité de l'air ont une importance aigüe en termes de risques naturels ou de risques sur la sante. Ces exemples attestent la nécessité d'utiliser des méthodes de descente d'échelle pour exploiter l'information météorologique et/ou climatique de grande échelle et dériver des scenarios locaux et régionaux appliques aux territoires insulaires. Ce défi est important car l'attente d'analyses scientifiques pertinentes dans ces domaines est grande.Les travaux présentés dans ce mémoire ont pour principaux objectifs la simulation numérique puis l'analyse des mécanismes méso- et micro-échelles qui induisent des circulations locales diurnes et nocturnes sur l'archipel de la Guadeloupe à l'aide de codes numériques météorologiques éprouves car largement utilises en recherche et en prévision opérationnelle.Ils constituent donc la première étude de modélisation numérique à haute résolution en basse atmosphère, par descente d'échelle dynamique, pour des intervalles d'espace compris entre 1 km et 111 m sur cet archipel.Le modelé atmosphérique Weather Research and Forecasting ARW V3.4 (WRF ARW), non-hydrostatique, a été utilise pour l'ensemble des simulations pour modéliser la troposphère depuis l'échelle globale à l'échelle de la turbulence.Trois situations météorologiques classiques réelles d'une durée de 48 heures, correspondant à 80 % des situations météorologiques observées dans la zone, alizes soutenus (AS), alizes moyens (AM), alizes faibles (AF) ont été examinées. Ces situations sont caractérisées par les valeurs du nombre de Froude local suivantes : 0,82 (AS), 0,41 (AM) et 0,21 (AF). Six domaines de modélisation ont été sélectionnés pour effectuer les descentes d'échelle dynamiques : D01 (maille de 27 km), D02 (maille de 9 km), D03 (maille de 3 km), D04 (maille de 1 km), D05 (maille de 333 m) et D06 (maille de 111 m) avec soixante-dix niveaux verticaux. Les quatre premiers domaines (D01 à D04) couvrent l'archipel de la Guadeloupe et sont utilisés en mode méso-échelle à l'aide d'un schéma d'ensemble de couche limite planétaire YSU. Les domaines D05 (couvrant l'île de la Basse-Terre et le centre de l'archipel) et D06 (couvrant la zone littorale et rurale du Petit Cul-de-Sac Marin et la zone urbaine de l'agglomération pointoise) sont utilisés en mode Large Eddy Simulation avec une fermeture de la turbulence 1,5 TKE 3D. Le modèle WRF a été forcé toutes les six heures par l'assimilation des champs d'analyses globales du modèle NCEP FNL (1° de résolution). Les simulations effectuées ont permis d'obtenir des champs de variables météorologiques 10-minutes à très hautes résolutions spatiales.Les résultats des simulations méso- et micro-échelles ont été confrontés aux valeurs expérimentales obtenues à l'aide de capteurs places sur des mâts météorologiques (campagne Atmo-Mangrov et réseau de mesure Météo-France). Il s'agissait d'optimiser l'utilisation des couplages de codes numériques tout en conservant la possibilité de les confronter aux observations expérimentales.Les résultats des simulations numériques micro-échelles, des différents cas (AS, AM, AF) sont utilisées pour forcer (c'est-à-dire définir les conditions limites) un modèle lagrangien de dispersion de particules : FLEXPART. Le système couple FLEXPART-WRF a été employé dans le domaine D06 pour étudier la dispersion du panache d'oxydes d'azote émis par la principale usine de production d'électricité de l'île.
The present work expresses the will of Caribbean researchers to improve the meso- and micro-meteorological scientific knowledge of the trade winds influenced island areas, and to develop research in these domains.It is well known that tropical hurricanes remain the most remarkable meteorological phenomena that affect the Caribbean islands. But some other phenomena, of smaller scale, such as intense rainfall events, swells, or air quality degradation, are of extreme importance for natural or health hazards. These examples show the need to use downscaling methods to exploit large scale meteorological or climatic information, and to obtain local and regional scenarios for the island areas. This is an important challenge, as sound scientific studies in these matters are eagerly expected. The aim of the research works exposed in the present dissertation is numerical simulation and analysis of the meso- and microscale mechanisms that induce diurnal and nocturnal local circulations in the Guadeloupe archipelago, using numerical meteorological models that are widely used in research and in operational forecasting.These works represent the first high-resolution (1 km to 111 m) numerical study of the lower atmosphere over the Guadeloupe archipelago. The Weather Research and Forecasting ARW 3.4 (WRF-ARW) model is used to simulate the troposphere from global scale to turbulence scale. Real cases of three typical weather types (80% of cases during a year) are examined during 48 hours : strong trade winds (STW), medium trade winds (MTW) and weak trade winds (WTW). These weather types are characterized by values of the local Froude number : 0.82 (STW), 0.41 (MTW) and 0.21 (WTW). Six domains have been selected for the dynamical downscaling : D01 (grid spacing of 27 km), D02 (grid spacing of 9 km), D03 (grid spacing of 3 km), D04 (grid spacing of 1 km), D05 (grid spacing of 333 m) and D06 (grid spacing of 111 m), including 70 vertical levels. The first four domains (D01 to D04) cover the Guadeloupe archipelago and are used in the meso-scale simulations with the planetary boundary layer scheme YSU (ensemble mean). Domain D05 (covering the Basse-Terre island and the middle of the archipelago) and domain D06 (covering the coastal and rural area of Le Petit Cul-de-Sac Marin and the urban area of Pointe-à-Pitre), are employed in the micro-scale simulation (LES) with the 3D TKE 1.5 order closure scheme. WRF has been 6 hourly reinitialized with the NCEP FNL global analyses (resolution of 1°). These simulations permitted to obtain 10-minutes meteorological variable fields with a very high resolution (111 m).Meso-scale and micro-scale model results have been evaluated with observational data from meteorological stations (field campaign Atmo-Mangrov, French Met Office).Once validated, the micro-scale model outputs have been used for the assimilation of the lagrangian particle dispersion model : FLEXPART. The coupling FLEXPART-WRF has been employed in domain D06, in order to analyze the dispersion of the nitrogen oxide plume emitted by the main power plant of the archipelago.

http://www.theses.fr/2014AGUY0735/document

Éditeur(s) : Ecole nationale supérieure agronomique de Rennes
Résumé : Describe and gain understanding on fluctuations in animal population over time and space is a central goal of population ecology. This is also crucial to ensure the sustainable management of exploited resources, particularly those with complex population dynamics such as the bluefin tuna. The goal of this work is to collect bluefin tuna catches from the ancestral Mediterranean and Atlantic trap fisheries to (i) characterise long-term fluctuations in bluefin tuna population migrating in the Mediterranean, (ii) analyse their causes et (iii) assess their implications for fisheries management. The bluefin tuna main biological and ecological characteristics are first detailed. Then, the first part presents the trap fishery, and the process of collect and validation of the historical catches. This leads to develop a data base of 54 time-series more than 20 years long, the longest ones spanning about four centuries. Mean historical catches were around 15 000 tons/year ([7 000;25 000]). Time-series are analysed in a second part. Temporal variability of trap catches may be decomposed in three components: 100-year-long periodic fluctuations, 20-year cycles and inter-annual variations. These medium- to long-term fluctuations, representing more than 50% of the variability in the time-series, were synchronous all around the western Mediterranean and adjacent North Atlantic. In contrast, short-term variability was synchronous at a local scale only. It is argued that long-term fluctuations in trap catches could be considered as a proxy for those in abundance, and a synthetic time-series is computed to depict them. Biological and ecological processes that could cause such long-term fluctuations are discussed in a third part. We tested whether long-term fluctuations in Atlantic bluefin tuna might be related to large-scale environmental changes, using long time-series of the North Atlantic Oscillation (NAO), the Length of the Day index (LOD, a proxy of the atmospheric circulation index ACI) and the temperature. Spectral analyses of trap catches, LOD and temperature displayed similar spectra with peak at low frequency, whereas those of the NAO exhibited a broad band spectrum. Regression analyses and tests of correlation did not reveal any clear relationship between trap catches on the one hand and NAO and LOD on the other hand. In contrast, long-term fluctuations in trap catches appear to be negatively and significantly related to long-term trends in temperature. Underlying processes that could explain such a relationship are discussed, with special focus on changes in migration patterns. Finally, implications of such fluctuations in term of fisheries management are discussed in a fourth part. A simulation framework, in which a simulated population dynamics model is coupled with a VPA, is built to test the pertinence of the diagnostic of stock assessment according to different scenarios on fluctuations origins and population status. In the hypothesis of fluctuations linked to variations in the recruitment, VPA appears able to reconstruct the fluctuations but the predictions may be biased if natural fluctuations are not taking into account. In the hypothesis of fluctuations linked to changes in migration pattern, VPA is not able to reconstruct the population dynamics. In a precautionary approach, quotas which follow may be unsuitable in the best case, at worst dangerous if they are defined in comparison with a reference point. The concept of cible reference points, fixe and unique over time, appears not relevant for bluefin tuna; estimate trajectory reference pertinent may prove to be more pertinent.
Décrire et comprendre les fluctuations spatio-temporelles des espèces animales constituent les enjeux majeurs de l'écologie. La question est également cruciale pour réussir la gestion durable des ressources exploitées, en particulier celle du thon rouge, grand pélagique migrateur à la dynamique complexe. L'objectif de ce travail est de collecter les captures historiques de thon rouge par les madragues méditerranéennes et proche atlantiques pour (i) caractériser les fluctuations à long terme de la population migrante en Méditerranée, (ii) étudier leur déterminisme et (iii) évaluer leurs implications en terme de gestion des pêcheries. Après avoir décrit les principales caractéristiques biologiques et écologiques du thon rouge, la première partie présente la pêcherie à la madrague, puis le processus de collecte et de validation des données historiques de captures. Ce dernier conduit à la mise en place d'une base de données de 54 séries de plus de 20 ans, dont les plus longues s'étendent sur près de 4 siècles. Les productions historiques sont estimées à environ 15 000 tonnes/an ([7 000;25 000]). Les séries historiques de captures sont analysées dans la seconde partie. Leur variabilité temporelle peut être décomposée en trois composantes : de larges cycles pseudo-séculaires, des variations périodiques d'une vingtaine d'années et des fluctuations inter-annuelles. Les fluctuations à moyen et long terme, expliquant plus de la moitié de la variance des séries, sont synchrones à l'échelle du bassin méditerranéen occidental et du proche Atlantique. La variabilité inter-annuelle, en revanche, n'est synchrone qu'à une échelle locale. On montre finalement que les fluctuations à long terme des captures peuvent être considérées comme de bons indices des tendances des abondances de la population de thons rouges migrants en Méditerranée. Une série synthétique est construite pour les décrire. Les processus biologiques et écologiques susceptibles d'être à l'origine de ces fluctuations sont discutés dans la troisième partie. L'hypothèse d'un forçage environnemental à grande échelle est testée en utilisant des indices à long terme de l'Oscillation Nord Atlantique (NAO), de la longueur du jour (LOD, un indicateur de l'indice de circulation atmosphérique ACI) et de la température. Les analyses spectrales sur les séries de captures, du LOD et des températures révèlent des spectres similaires, avec un pic sur les basses fréquences, alors que celles sur le NAO conduisent à une large bande spectrale. Les régressions et les tests de corrélations ne montrent aucune relation significative entre les captures par les madragues et le NAO et le LOD. En revanche, les fluctuations à long terme des captures apparaissent significativement et négativement corrélées avec les fluctuations à long terme des températures. Les processus sous-jacents susceptibles d'expliquer une telle relation, en particulier des changements migratoires, sont discutés. Finalement, les implications des fluctuations pour la gestion de la pêcherie sont discutées dans une quatrième partie. Un cadre de simulation, couplant un modèle de dynamique de population à une VPA, est élaboré pour tester la pertinence des diagnostics d'évaluation de stock selon différents scénarios d'origine des fluctuations et d'état de la population. Dans l'hypothèse de fluctuations liées à des variations du recrutement, la VPA apparaît capable de reconstruire les fluctuations mais les prédictions sont biaisées lorsqu'il n'est pas tenu compte des fluctuations naturelles du stock. Dans l'hypothèse de fluctuations liées à des changements migratoires, la VPA est alors incapable de reproduire la dynamique de la population. Dans une approche de précaution, les quotas qui en découlent peuvent se révéler au mieux inappropriés, au pire dangereux s'ils sont définis par rapport à un point de référence. Ce concept de point cible, fixe et unique dans le temps, apparaît inapproprié pour le thon rouge ; estimer des "trajectoires de référence" serait sans doute plus pertinent.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2003/these-65.pdf
http://archimer.ifremer.fr/doc/00000/65/

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : The aim of this paper is to study Moroccan music festivals against the existing theories on globalization, while coming up with new concepts aimed at overcoming the problems often facing experts in popular culture and media studies who feel that globalization thesis lapses into fatal gestures of leveling, reductionism, and totalitarianism, especially when it tries to account for current discussions related to the circulation of artifacts and cultural texts. The general consensus has it that modern technologies have hugely altered the meaning and revolutionized the traditional functions attached to art and cultural industries. The grotesque circulation of western cultural artifacts is justifiably judged to be many times agonizing for theorists in cultural studies, linguistics and political science, etc who want to be sure that the unequal transmissions of products across the world will not harm local cultural, linguistic and economic capital of the less dominant other. Moroccan music festivals for instance are seen to be increasingly governed by a complex whirlpool of the far-too-melodramatic implications of today’s world global connections. In view of this, this paper, which borrows from data collected during between 2010 and 2011, will examine cultural industries, music festivals in general and the Essaouira festival in particular, in relation to world flows, while holding the argument that the appropriation of western artifacts locally has always been part of a not-so-novel process of mobility of what we call world cultural nomadictates (nomadic dictates). The paper gives a detailed definition of this concept and develops other new concepts (e.g. recurents, exclusives) related to the «glocal» face of culture and art in Morocco in an attempt to find an escape route outside the impasses of the globalization/cultural imperialism theses surrounding the study of cultural industries. To drive this idea home, we will open up the discussion at hand onto existing controversies around notions of place, authenticity, urbanism, tourism and consumption.
L'objectif de cette recherche est d’étudier les festivals de musique marocains en portant un regard critique sur les théories existantes de la mondialisation et en proposant de nouveaux concepts afin de surmonter les problèmes auxquels les théoriciens de la culture populaire et des médias se sont souvent confrontés. Selon eux, le concept de mondialisation sombre dans le réductionnisme et le totalitarisme, surtout lorsqu’il s’agit de la circulation des objets et des textes culturels. Un consensus général semble s’être développé autour de l’idée selon laquelle les technologies modernes ont considérablement altéré et révolutionné le sens et les fonctions traditionnelles de l'art et des industries culturelles. L'insolite diffusion des objets culturels occidentaux est à juste titre source d’angoisse pour les théoriciens des études culturelles, de la linguistique, et des sciences politiques qui veulent s'assurer que la transmission inégale des produits dans le monde ne nuira pas au capital local, culturel, linguistique et économique de l'autre (le moins dominant). Les festivals de musique marocains, par exemple, sont perçus comme étant de plus en plus tributaires des vicissitudes de la mondialisation actuelle. Dans cette perspective, cette recherche, s'inspire de données recueillies au cours de deux années de travail de terrain (2010/2011), et se penche sur les flux mondiaux de produits culturels qui mettent en interface les industries culturelles, les festivals de musique en général et celui d'Essaouira en particulier. Elle maintient l'idée selon laquelle l'appropriation des objets occidentaux par les communautés locales a toujours fait partie d'un processus de mobilité, qui n'est pas si récent, de ce que nous appelons les ‘nomadictâtes’ culturels du monde (dictâtes nomades). En explicitant la définition de ce concept, cette recherche développe d'autres concepts liés à la notion de glocalité de la culture et de l'art au Maroc. Enfin, elle suggère aussi une issue à l’impasse des théories de la mondialisation traditionnelles et celle de l’impérialisme culturel en particulier dans lesquelles l’étude des industries culturelles semble s’être emprisonnée. Pour ce faire, nous exposons le débat actuel sur les controverses autour des notions de lieu, d'authenticité, d'urbanisme, de tourisme, et de consommation.
Maroc

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.5993
http://journals.openedition.org/etudescaribeennes/5993

Éditeur(s) : HAL CCSD World Scientific
Résumé : The present paper presents a laboratory experiment of rip current circulations over a moveable bed. The rip current characteristics over four distinct beach morphologies, exhibiting more or less developed nature-like bar-rip morphology,were investigated. For each video run, the same off shore shore-normal waves were generated by the wave maker with the same mean water level in order to study the sensitivity of the rip current characteristics as a function of the beach morphology only. In each case, a 1-hour video run was used to track a large number (~30) of drifters released within the surf zone. Image coordinates were then rectifie d to still water level Cartesian coordinates to compute drifter velocities, mean characteristics and surf zone rete ntion rates. Results show the presence of classic rip current patterns with counter-rotating cells and a relatively narrowoffshore-directed jet with, for three of the situations, a reasonably symmetric shape. Non-surprisingly, it was found that rip current intensity increases with increasing relative depth of the rip channel. The wave-driven circulations were strongly unstable. Computed standard deviation in fl ow intensity and direction provides high resolution information on the spatial variability of the rip current insta bilities with, for instance, highly-pulsating and weakly directionally variable offshore-directed flow in the rip channel. Conversely to what was previously hypothesized in the literature, there was hardly trace of vortices being shed offs hore and drifters exiting the surf zone compartment were not systematically caught by a pulsating jet. The cause for drifter exiting the semi-enclosed surf zone compartment remains, however, elusive and deserves further investigations. The computed surf zone retention rates (~90%) were of the order of those previously observed in the field, with no clear relationship with the mean rip current velocity or relative depth of the rip channel. Further video-runs will have to be analyzed to explore potential explanations
Proceedings of Coastal Dynamics 2009 Impacts of Human Activities on Dynamic Coastal Processes

ISBN : 978-981-4282-46
hal-00854534
https://hal.archives-ouvertes.fr/hal-00854534

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Holocene Lake Mega-Chad (LMC) was the largest late Quaternary water-body in Africa. The development of this giant paleo-lake is related to a northward shift of the isohyetes interpreted as evidence for an enhanced Monsoon (African Humid Period). Numerous preserved coastal features have been described all around the LMC shore. Such features reveal the main paleo-hydrodynamical tendencies. In the context of a closed water-body like LMC, hydrodynamics are forced mainly by winds. We use a three-dimensional numerical model (SYMPHONIE) to simulate the mean hydrodynamics in LMC under both Harmattan-like (northeasterly trade winds) and Monsoon-like (southwesterly winds) forcings. The northern part of LMC displays coastal features, such as sand spits, that are consistent with the simulations forced by Harmattan-like winds. Geomorphic features related to Monsoon-driven hydrodynamics are not clearly expressed. They could have developed during the early stage of LMC but subsequently reworked. At the time of sand-spit building, Harmattan-like driven hydrodynamics prevailed and related coastal features were preferentially preserved in the sedimentary record.
ISSN: 0033-5894

hal-00475633
https://hal.archives-ouvertes.fr/hal-00475633
DOI : 10.1016/j.yqres.2009.10.010

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Gulf of Cadiz lies astride the complex plate boundary between Africa and Eurasia west of the Betic-Rif mountain belt. We report on the results of recent bathymetric swathmapping and multi-channel seismic surveys carried out here. The seafloor is marked by contrasting morphological provinces, spanning the SW Iberian and NW Moroccan continental margins, abyssal plains and an elongate, arcuate, accretionary wedge. A wide variety of tectonic and gravitational processes appear to have shaped these structures. Active compressional deformation of the wedge is suggested by folding and thrusting of the frontal sedimentary layers as well as basal duplexing in deeper internal units. There is evidence for simultaneous gravitational spreading occurring upslope. The very shallow mean surface and basal slopes of the accretionary wedge (1° each) indicate a very weak decollement layer, geometrically similar to the Mediterranean Ridge accretionary complex. Locally steep slopes (up to 10°) indicate strongly focused, active deformation and potential gravitational instabilities. The unusual surface morphology of the upper accretionary wedge includes “raft-tectonics” type fissures and abundant sub-circular depressions. Dissolution and/or diapiric processes are proposed to be involved in the formation of these depressions.
ISSN: 0264-8172

insu-00401683
https://hal-insu.archives-ouvertes.fr/insu-00401683
DOI : 10.1016/j.marpetgeo.2007.11.008

Éditeur(s) : Springer
Résumé : Series of sensitivity tests were performed with a z-coordinate, global eddy-permitting (1/4 degrees) ocean/sea-ice model (the ORCA-R025 model configuration developed for the DRAKKAR project) to carefully evaluate the impact of recent state-of-the-art numerical schemes on model solutions. The combination of an energy-enstrophy conserving (EEN) scheme for momentum advection with a partial step (PS) representation of the bottom topography yields significant improvements in the mean circulation. Well known biases in the representation of western boundary currents, such as in the Atlantic the detachment of the Gulf Stream, the path of the North Atlantic Current, the location of the Confluence, and the strength of the Zapiola Eddy in the south Atlantic, are partly corrected. Similar improvements are found in the Pacific, Indian, and Southern Oceans, and characteristics of the mean flow are generally much closer to observations. Comparisons with other state-of-the-art models show that the ORCA-R025 configuration generally performs better at similar resolution. In addition, the model solution is often comparable to solutions obtained at 1/6 or 1/10 degrees resolution in some aspects concerning mean flow patterns and distribution of eddy kinetic energy. Although the reasons for these improvements are not analyzed in detail in this paper, evidence is shown that the combination of EEN with PS reduces numerical noise near the bottom, which is likely to affect current-topography interactions in a systematic way. We conclude that significant corrections of the mean biases presently seen in general circulation model solutions at eddy-permitting resolution can still be expected from the development of numerical methods, which represent an alternative to increasing resolution.
Ocean Dynamics (1616-7341) (Springer), 2006-12 , Vol. 56 , N. 5-6 , P. 543-567

Droits : © Springer 2006. Part of Springer Science+Business Media
http://archimer.ifremer.fr/doc/2006/publication-3514.pdf
DOI:10.1007/s10236-006-0082-1
http://archimer.ifremer.fr/doc/00000/3514/

Éditeur(s) : Public Library Science
Résumé : Studying the larval dispersal of bottom-dwelling species is necessary to understand their population dynamics and optimize their management. The black-lip pearl oyster (Pinctada margaritifera) is cultured extensively to produce black pearls, especially in French Polynesia's atoll lagoons. This aquaculture relies on spat collection, a process that can be optimized by understanding which factors influence larval dispersal. Here, we investigate the sensitivity of P. margaritifera larval dispersal kernel to both physical and biological factors in the lagoon of Ahe atoll. Specifically, using a validated 3D larval dispersal model, the variability of lagoon-scale connectivity is investigated against wind forcing, depth and location of larval release, destination location, vertical swimming behavior and pelagic larval duration (PLD) factors. The potential connectivity was spatially weighted according to both the natural and cultivated broodstock densities to provide a realistic view of connectivity. We found that the mean pattern of potential connectivity was driven by the southwest and northeast main barotropic circulation structures, with high retention levels in both. Destination locations, spawning sites and PLD were the main drivers of potential connectivity, explaining respectively 26%, 59% and 5% of the variance. Differences between potential and realistic connectivity showed the significant contribution of the pearl oyster broodstock location to its own dynamics. Realistic connectivity showed larger larval supply in the western destination locations, which are preferentially used by farmers for spat collection. In addition, larval supply in the same sectors was enhanced during summer wind conditions. These results provide new cues to understanding the dynamics of bottom-dwelling populations in atoll lagoons, and show how to take advantage of numerical models for pearl oyster management.
Plos One (1932-6203) (Public Library Science), 2014-04 , Vol. 9 , N. 4 , P. e95050

Droits : 2014 Thomas et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
http://archimer.ifremer.fr/doc/00197/30843/29210.pdf
DOI:10.1371/journal.pone.0095050
http://archimer.ifremer.fr/doc/00197/30843/

Éditeur(s) : HAL CCSD
Résumé : International audience
Estrogens affect brain development of vertebrates, not only by impacting activity and morphology of existing circuits, but also by modulating embryonic and adult neurogenesis. The issue is complex as estrogens can not only originate from peripheral tissues, but also be locally produced within the brain itself due to local aromatization of androgens. In this respect, teleost fishes are quite unique because aromatase is expressed exclusively in radial glial cells, which represent pluripotent cells in the brain of all vertebrates. Expression of aromatase in the brain of fish is also strongly stimulated by estrogens and some androgens. This creates a very intriguing positive auto-regulatory loop leading to dramatic aromatase expression in sexually mature fish with elevated levels of circulating steroids. Looking at the effects of estrogens or anti-estrogens in the brain of adult zebrafish showed that estrogens inhibit rather than stimulate cell proliferation and newborn cell migration. The functional meaning of these observations is still unclear, but these data suggest that the brain of fish is experiencing constant remodeling under the influence of circulating steroids and brain-derived neurosteroids, possibly permitting a diversification of sexual strategies, notably hermaphroditism. Recent data in frogs indicate that aromatase expression is limited to neurons and do not concern radial glial cells. Thus, until now, there is no other example of vertebrates in which radial progenitors express aromatase. This raises the question of when and why these new features were gained and what are their adaptive benefits. This article is part of a Special Issue entitled: Nuclear receptors in animal development.
Biochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanisms

Droits : info:eu-repo/semantics/OpenAccess
hal-01102449
https://hal.archives-ouvertes.fr/hal-01102449
https://hal.archives-ouvertes.fr/hal-01102449/document
https://hal.archives-ouvertes.fr/hal-01102449/file/Coumailleau%20et%20al%20final%20manuscript.pdf
DOI : 10.1016/j.bbagrm.2014.07.002

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
This study describes a laboratory experiment on rip current circulations over a moveable bed. Rip current characteristics over eight contrasting nature-like beach morphologies are investigated. The seabed varied from reasonably alongshore uniform to strongly alongshore nonuniform with crescentic patterns and bar-rip morphologies, representative of a full morphological down-state sequence. The same offshore shore-normal waves were generated by the wavemaker for the eight situations with the same mean water level to study the sensitivity of rip current characteristics as a function of the beach morphology only. In each case, a 30 to 60 min video run was used to track a large number of drifters released within the surf zone. Results show the presence of classic rip current patterns with counterrotating cells and a relatively narrow offshore-directed jet varying from shore-normal to strongly skewed. Wave-driven circulations were strongly unstable. Computed standard deviations of flow intensity and direction provide high-resolution information on the spatial variability of rip current instabilities. Highly pulsating and weakly directionally variable offshore-directed flow is observed in the rip neck for well-developed bar-rip morphologies that turns into a weakly pulsating and highly directional variable rip current flow with decreasing beach alongshore nonuniformity. Proposing a definition of rip current intensity based on the rip current circulation geometry, rip current intensity was found to linearly increase with increasing measure of beach alongshore nonuniformity within both the low-energy and moderate-energy rip current regimes. To date, our laboratory experiment provides the first extensive quantitative rip current information during a full down-state sequence for a given wave condition.
ISSN: 0148-0227

hal-00602920
https://hal.archives-ouvertes.fr/hal-00602920
DOI : 10.1029/2010JC006343

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
The impact of stratospheric ozone on the tropospheric general circulation of theSouthern Hemisphere (SH) is examined with a set of chemistry‐climate models participatingin the Stratospheric Processes and their Role in Climate (SPARC)/Chemistry‐ClimateModel Validation project phase 2 (CCMVal‐2). Model integrations of both the past andfuture climates reveal the crucial role of stratospheric ozone in driving SH circulationchange: stronger ozone depletion in late spring generally leads to greater polewarddisplacement and intensification of the tropospheric midlatitude jet, and greater expansion ofthe SH Hadley cell in the summer. These circulation changes are systematic as polewarddisplacement of the jet is typically accompanied by intensification of the jet and expansion ofthe Hadley cell. Overall results are compared with coupled models participating in theIntergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4), andpossible mechanisms are discussed. While the tropospheric circulation response appearsquasi‐linearly related to stratospheric ozone changes, the quantitative response to a givenforcing varies considerably from one model to another. This scatter partly results fromdifferences in model climatology. It is shown that poleward intensification of the westerly jetis generally stronger in models whose climatological jet is biased toward lower latitudes.This result is discussed in the context of quasi‐geostrophic zonal mean dynamics.
ISSN: 2169-897X

hal-00337060
https://hal.archives-ouvertes.fr/hal-00337060
https://hal.archives-ouvertes.fr/hal-00337060/document
https://hal.archives-ouvertes.fr/hal-00337060/file/Bock_et_al-2008-Journalsur Geophysical_Research__Solid_Earth_%281978-2012%29.pdf
DOI : 10.1029/2008JD010327

Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : We report rare earth element (REE) and neodymium (Nd) isotope data for the organic fraction of sediments collected from various depositional environments, i.e. rivers (n=25), estuaries (n=18), open-ocean settings (n=15), and cold seeps (n=12). Sedimentary Organic Matter (SOM) was extracted using a mixed hydrogen peroxide/nitric acid solution (20%-H2O2 – 0.02M-HNO3), after removal of carbonate and oxy-hydroxide phases with dilute hydrochloric acid (0.25M-HCl). A series of experimental tests indicate that extraction of sedimentary organic compounds using H202 may be complicated occasionally by partial dissolution of sulphide minerals and residual carbonates. However, this contamination is expected to be minor for REE because measured concentrations in H2O2 leachates are about two-orders of magnitude higher than in the above mentioned phases. The mean REE concentrations determined in the H2O2 leachates for samples from rivers, estuaries, coastal seas and open-ocean settings yield relatively similar levels, with ΣREE = 109 ± 86 ppm (mean ± s; n=58). The organic fractions leached from cold seep sediments display even higher concentration levels (285 ± 150 ppm; mean ± s; n=12). The H2O2 leachates for most sediments exhibit remarkably similar shale-normalized REE patterns, all characterized by a mid-REE enrichment compared to the other REE. This suggests that the distribution of REE in leached sedimentary organic phases is controlled primarily by biogeochemical processes, rather than by the composition of the source from which they derive (e.g. pore, river or sea- water). The Nd isotopic compositions for organic phases leached from river sediments are very similar to those for the corresponding detrital fractions. In contrast, the SOM extracted from marine sediments display εNd values that typically range between the εNd signatures for terrestrial organic matter (inferred from the analysis of the sedimentary detrital fractions) and marine organic matter (inferred from the analysis of local surface seawater). A notable exception is the case of organic matter (OM) fractions leached from cold seep sediment samples, which sometimes exhibit εNd values markedly different from both terrigenous and surface seawater signatures. This suggests that a significant fraction of organic compounds in these sediments may be derived from chemosynthetic processes, recycling pore water REE characterized by a distinct isotopic composition. Overall, our results confirm that organic matter probably plays an important role in the oceanic REE budget, through direct scavenging and remineralization within the water column. Both the high REE abundances and the shape of shale-normalized patterns for leached SOM also suggest that OM degradation in sub-surface marine sediments during early diagenesis could control, to a large extent, the distribution of REE in pore waters. Benthic fluxes of organic-bound REE could hence substantially contribute to the exchange processes between particulates and seawater that take place at ocean margins. Neodymium isotopes could provide useful information for tracing the origin (terrestrial versus marine) and geographical provenance of organic matter, with potential applications in paleoceanography. In particular, future studies should further investigate the potential of Nd isotopes in organic compounds preserved in sedimentary records for reconstructing past variations of surface ocean circulation.
Geochimica Et Cosmochimica Acta (0016-7037) (Pergamon-elsevier Science Ltd), 2014-09 , Vol. 140 , P. 177-198

Droits : 2014 Elsevier Ltd. All rights reserved.
http://archimer.ifremer.fr/doc/00191/30250/28682.pdf
DOI:10.1016/j.gca.2014.05.016
http://archimer.ifremer.fr/doc/00191/30250/

Résumé : La tuberculose (TB), maladie infectieuse contagieuse, est causée par une mycobactérie appartenant au complexe Mycobacterium tuberculosis (MTBC). Malgré de nombreuses campagnes de vaccination par le BCG (Bacilles de Calmette et Guérin) et les traitements antituberculeux, on observe une réémergence de la maladie depuis les années 80. Ce bouleversement s’explique par la coïnfection avec le virus du VIH/SIDA, la désorganisation des systèmes de santé et par l’apparition des bactéries résistantes aux principaux antibiotiques antituberculeux. Dans ce contexte une meilleure connaissance des mouvements et de l’évolution des clones circulants du bacille tuberculeux permettrait de détecter plus rapidement et de façon plus pertinente l’émergence d’épidémies. Le contrôle et la surveillance de la maladie représentent des moyens essentiels pour lutter contre l’expansion mondiale de la tuberculose. C’est ainsi que l’unité de la Tuberculose et des Mycobactéries de l’Institut Pasteur de la Guadeloupe (IPG) a mis en place une base de données de profils génotypiques pour l’étude de l’épidémiologie globale de la tuberculose. Dans le cadre de cette thèse, nous décrirons les méthodes de bioinformatique qui ont été utilisées pour la gestion et l’exploitation de la 6ème version (SITVIT2) de cette base de données des génotypes pour mieux comprendre l’évolution et la dissémination mondiale du bacille tuberculeux. Cette base intègre aussi plusieurs marqueurs moléculaires tels que les MIRU-VNTRs (« mycobacterial interspersed repetitive units-variable number of tandem repeats ») et le Spoligotype43 servant à mieux décrire et identifier les familles de profils génotypiques du MTBC. La banque de données SITVIT2 ne cesse d’évoluer, et elle contient actuellement des informations épidémiologiques sur 111 635 isolats cliniques. Cette base de données est consultable en ligne à l’adresse suivante : http://www.pasteur-guadeloupe.fr:8081/SITVIT2/. Nous avons également réalisé une base de données nommée SITVITBovis qui est dédiée à la tuberculose bovine. Cette base de données sera accessible à l’adresse : http://www.pasteur-guadeloupe.fr:8081/SITVIT_Bovis/. Parallèlement au développement et à la gestion des bases de données, ce travail de thèse s’est appuyé sur plusieurs études épidémiologiques et phylogéographiques mettant en corrélation les données disponibles sur la résistance aux médicaments ou les caractéristiques démographiques (dont le sexe, l’âge, le statut VIH, et l’origine du patient). Notre initiative de recherche permet ainsi d’améliorer la caractérisation phylogénétique détaillée des lignées du MTBC, ainsi que l’épidémiologie des clones en circulation, afin d’élaborer une cartographie géographique des isolats cliniques prédominants pour les bacilles tuberculeux principalement impliqués dans la maladie, à l’échelle nationale, régionale et mondiale. La superposition ultérieure de ces cartes avec des données sociopolitiques, économiques et démographiques obtenues auprès de Systèmes d’information géographique (SIG) ont permis de dresser un portrait précis des disparités actuelles par pays ou sous-région. Cette thèse représente une importante collaboration avec plusieurs équipes de chercheurs travaillant également dans le domaine de l’épidémiologie moléculaire de la tuberculose. L’objectif à long terme de ce travail, est d’optimiser la structure de la base, et de pérenniser l’enrichissement de celle-ci (notamment par l’automatisation et la facilité de la saisie de données). Une représentation optimale et une meilleure accessibilité des données de la base conforteraient les efforts faits pour le contrôle et la surveillance de la TB dans monde.
Tuberculosis (TB) is a contagious infectious disease caused by mycobacteria belonging to the Mycobacterium tuberculosis complex (MTBC). Despite numerous campaigns of vaccination by the BCG (Bacillus Calmette-Guérin) vaccine, and TB treatments, there was a resurgence of the disease since the 80s. This disruption is due to coinfection with HIV/AIDS, disorganization of health systems and the emergence of bacteria resistant to anti-TB drugs. In this context, a better understanding of the movements and changes of circulating clones of tubercle bacilli would detect faster and more relevant emerging epidemics. The control and monitoring of the disease are essential means to fight against the worldwide spread of tuberculosis. Thus the TB and Mycobacteria unit of the Pasteur Institute of Guadeloupe (IPG) has developed a database of genotypic profiles for the study of global epidemiology of tuberculosis.In this thesis, we discuss the Bioinformatical methods that have been used for the management and development of the 6th version (SITVIT2) of this database of genotypes to better understand the evolution and global dissemination of the tubercle bacillus. The database also includes several molecular markers such as MIRU-VNTRs (mycobacterial interspersed repetitive units- variable number of tandem repeats) and Spoligotype43 allowing a better description and identification of the families of genotypic profiles of Mycobacterium tuberculosis complex. SITVIT2 database is constantly evolving, and it currently contains epidemiological information on 111,635 clinical isolates. This database is available online at the following address: http://www.pasteur-guadeloupe.fr:8081/SITVIT2/. We also developed a database named "SITVITBovis", which is dedicated to bovine tuberculosis. This database will be accessible at: http://www.pasteur-guadeloupe.fr:8081/SITVIT_Bovis/.Alongside the development and management of databases, this work was based on several epidemiological and phylogeographic studies correlating data on drug resistance or demographic characteristics (including sex, age, HIV status, and the origin of the patient). Our research initiative is thus focused to further improve in depth phylogenetic characterization of MTBC lineages, as well as the epidemiological analysis of circulating clones to generate evidence-based geographical mapping of predominant clinical isolates of tubercle bacilli causing the bulk of the disease both at country and regional level. Further superposition of these maps with socio-political, economical and demographical available through Geographic Information Systems (GIS) allows to have a precise view of prevailing disparities at the level of country or sub-region. This thesis represents an important collaboration with several researchers teams also working in the field of molecular epidemiology of tuberculosis.The long-term goal of this work is to further optimize the database structure, and sustain enriching it (including automation and ease of data entry). Optimum performance and accessibility of data in the database would reinforce efforts to control and surveillance of TB in the world.

http://www.theses.fr/2014AGUY0791/document

Éditeur(s) : HAL CCSD
Résumé : International audience
AIM:We aimed to study the relationships between circulating 25-hydroxyvitamin D [25(OH)D], insulin resistance and leptin-to-adiponectin (L/A) ratio in Guadeloupean children and adolescents and to analyse the changes in 25(OH)D levels after a 1-year lifestyle intervention program.METHODS:25(OH)D concentrations were measured via a chemiluminescence assay. Cardiometabolic risk factors, homoeostasis model assessment of insulin resistance (HOMA-IR), and adipokines were measured. The lifestyle intervention included dietary counselling, regular physical activity.RESULTS:Among 117 girls and boys (11–15 years old, 31.6% obese), 40% had vitamin D deficiency (25(OH)D levels < 20 ng/mL). With linear regression models where 25(OH)D and HOMA-IR acted as independent variables and age, sex, BMI, L/A ratio as covariates, 25(OH)D was significantly associated with HOMA-IR alone (P = 0.036). HOMA-IR was also associated with BMI z-score ≥ 2, L/A ratio and an interaction term BMI z-score ≥ 2*L/A ratio (P < 0.001 for all). After one year, in 78 children/adolescent, mean serum 25(OH)D increased significantly from 21.4 ± 4.9 ng/mL at baseline to 23.2 ± 6.0 after 1 year; P = 0.003 whereas BMI z-score, HOMA-IR and L/A ratio decreased significantly (P = 0.003, P < 0.001 and P = 0.012; respectively).CONCLUSION:The association between 25(OH)D and HOMA-IR, independently of obesity and the high prevalence of vitamin D deficiency should be considered in order to prevent the later incidence of T2DM. A healthy lifestyle including non-sedentary and outdoor activities could be a way for improving vitamin D status.
Open Access Macedonian Journal of Medical Sciences

hal-01427889
http://hal.upmc.fr/hal-01427889
PUBMEDCENTRAL : PMC5175505

Éditeur(s) : HAL CCSD
Résumé : Red blood cell hemodynamics influence blood rheology and thus circulatory function. Different authors showed that red blood cells are heterogeneous in blood flow. This heterogeneity could be explained by physical characteristics such as morphology, aggregability and deformability, but also by cellular and molecular environment. All these notions are found in sickle cell disease where sickle red blood cells become more rigid, leading to vascular occlusions, increased with an inflammatory context. In a preceding study, our results showed that velocity heterogeneity allow RBC classification, leading to different RBC sub-groups, using a dynamical approach and flow studies. In order to have a better understanding of the physiological meaning of such an heterogeneity, dynamical velocity experiences have been conducted in the case of normal and sickle red blood cells with different endothelial activations by proinflammatory cytokines, under a constant venular flow. Thus, normal and sickle red blood cells are classified into different sub-groups, showing their heterogeneity. Moreover, sub-population velocities and distribution evolve differently according to vascular state or treatment. These results show that red blood cell velocities and rheology depend on vascular environment and red blood cell morphology. However, the physiological meaning of this behavior should be explained by cellular and molecular effects of such activation.
https://hal.archives-ouvertes.fr/hal-00201461

hal-00201461
https://hal.archives-ouvertes.fr/hal-00201461
https://hal.archives-ouvertes.fr/hal-00201461/document
https://hal.archives-ouvertes.fr/hal-00201461/file/RBCV_Marianne_v1.pdf