Éditeur(s) : HAL CCSD American Society of Tropical Medicine and Hygiene
Résumé : International audience
From September 2013 to July 2014, several gold miners working in the tropical forest consulted the Maripasoula Health Center in French Guiana for edema and findings consistent with right cardiac failure. Of the 42 cases of beriberi that were diagnosed, one patient died. The laboratory and clinical investigation demonstrated vitamin B1 deficiency in most of the patients tested. Furthermore, 30 of 42 patients responded favorably to 500 mg of intravenous or intramuscular thiamine supplementation. In addition, dietary investigation showed insufficient thiamine intake in these patients. We concluded that patients had acquired beriberi because of diet restrictions, hard labor, and infectious diseases, notably malaria. In 2016, cases were still being reported. We recommend screening for compatible symptoms in gold miners, thiamine supplementation, and nutritional intervention
ISSN: 0002-9637

inserm-01503899
http://www.hal.inserm.fr/inserm-01503899
http://www.hal.inserm.fr/inserm-01503899/document
http://www.hal.inserm.fr/inserm-01503899/file/2017%2C%20Mosnier%20-%20A%20Large%20Outbreak%20of%20Thiamine%20Deficiency%20among%20Illegal%20Gold%20Miners%20in%20French%20Guiana.pdf
DOI : 10.4269/ajtmh.15-0906

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Pathogenic agents can be very hard to detect, and usually they do not cause illness for several hours or days. To improve the speed and the accuracy of detection tests and satisfy the needs of early diagnosis, molecular biology methods such as PCR are now used. However, selecting a proper target gene and designing good primers is often not easy. We present a dedicated website, http://patho-genes.org, where we provide every sequence, functional annotation, published primer and relevant article for every annotated gene of major pathogenic bacterial species listed as key agents to be used for a bioterrorism attack. Each published primer was analysed to determine its melting temperature, its specificity and its coverage (i.e. its sensitivity against every allele of its target gene). Data generated have been organized in the form of data sheet for each gene, which are available through multiple browser panels and query systems.
ISSN: 1751-7915

hal-01546181
https://hal.archives-ouvertes.fr/hal-01546181
DOI : 10.1111/j.1751-7915.2012.00353.x

Éditeur(s) : EDP Sciences
Résumé : The necessity to move from a traditional fishery management to an ecosystem approach is now acknowledged. Indicators are required to support the development of this approach. For example, community indicators have been proposed to assess the impact of fishing. We tested here the applicability of one such community indicator, the abundance-biomass comparison (ABC method), as a measure of the impact of bottom trawling (years of sampling: 2001 and 2003) on the benthic invertebrates-typically starfishes, crabs, squat lobsters, shrimps and large hard-shelled molluscs-of "Grande Vasiere", a major French fishing zone, in the Bay of Biscay. The ABC method is generally used as an impact indicator for different types of physical, biological and anthropogenic disturbances on benthic communities. This method is based on the assumption that increasing disturbance shifts communities from dominance by large-bodied species with low turnover rates toward dominance by small-bodied species with high turnover rates. At less disturbed areas the average biomass of individuals is greater than at more heavily disturbed areas. The ABC method measures this effect by comparing the ranked distributions of abundance and biomass within a given community. We applied the ABC method and compared the size structure and the species diversity at two areas exposed to moderate and high bottom trawl effort. Species diversity was lower in the most exploited area. The highly trawled area was dominated by opportunistic organisms, mainly one species of swimming crab Liocarcinus depurator, one species of squat lobster Munida rugosa and Norway lobsters Nephrops norvegicus, which are large-bodied species. Consequently, the results of the ABC method were inconsistent with the theoretical expectation for these particular macrofaunal communities and the measured levels of fishing intensity.
La nécessité de passer d'une gestion monospécifique des pêches à une approche écosystémique est largement reconnue. Pour mettre en place une telle approche, des indicateurs ont été proposés afin d'estimer l'impact de la pêche sur les communautés. Nous avons testé l'efficacité de l'un de ces indicateurs, la comparaison abondance-biomasse (méthode ABC), pour mesurer l'impact du chalutage de fond (année d'échantillonnage : 2001 et 2003) sur les communautés de la macrofaune benthique de la Grande Vasière, golfe de Gascogne (typiquement des crabes, étoiles de mer, des galathées, de gros mollusques à coquille dure). La méthode ABC est généralement utilisée comme un indicateur d'impact de différents types de perturbations physiques, biologiques et anthropiques sur les communautés benthiques. Cette méthode est basée sur l'hypothèse qu'un régime de perturbation croissant entraîne une modification de la structure des communautés qui deviennent graduellement dominées par des espèces opportunistes de petite taille caractérisées par un renouvellement rapide. Dans une communauté modérément perturbée, la biomasse moyenne des individus est ainsi plus grande que dans une communauté fortement perturbée. La méthode ABC mesure cet effet en comparant les distributions en biomasse et densité dans chaque communauté. Nous avons appliqué la méthode ABC et étudié la structure en taille et la diversité spécifique des communautés benthiques en comparant deux zones, l'une soumise à un effort de pêche modéré et l'autre à un important effort de pêche. La diversité spécifique était plus faible sur les sites fortement chalutés. Ces sites étaient dominés par des organismes opportunistes de grande taille, principalement une espèce de crabe nageur Liocarcinus depurator, une espèce de galathée Munida rugosa et des langoustines Nephrops norvegicus. Dans ces conditions, les résultats de la méthode ABC n'étaient pas cohérents avec la théorie pour ces communautés de macro-invertébrés benthiques et les efforts de pêche mesurés.
Aquatic Living Resources (0990-7440) (EDP Sciences), 2006-07 , Vol. 19 , N. 3 , P. 219-228

Droits : 2006 EDP
http://archimer.ifremer.fr/doc/2006/publication-2133.pdf
DOI:10.1051/alr:2006022
http://archimer.ifremer.fr/doc/00000/2133/

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Benthic cyanobacterial mats (BCMs) are impacting coral reefs worldwide. However, the factors and mechanisms driving their proliferation are unclear. We conducted a multi-year survey around the Caribbean island of Curaçao, which revealed highest BCM abundance on sheltered reefs close to urbanised areas. Reefs with high BCM abundance were also characterised by high benthic cover of macroalgae and low cover of corals. Nutrient concentrations in the water-column were consistently low, but markedly increased just above substrata (both sandy and hard) covered with BCMs. This was true for sites with both high and low BCM coverage, suggesting that BCM growth is stimulated by a localised, sub-strate-linked release of nutrients from the microbial degradation of organic matter. This hypothesis was supported by a higher organic content in sediments on reefs with high BCM coverage, and by an in situ experiment which showed that BCMs grew within days on sediments enriched with organic matter (Spirulina). We propose that nutrient runoff from urban-ised areas stimulates phototrophic blooms and enhances organic matter concentrations on the reef. This organic matter is transported by currents and settles on the seabed at sites with low hydrodynamics. Subsequently, nutrients released from the organic matter degradation fuel the growth of BCMs. Improved management of nutrients generated on land should lower organic loading of sediments and other benthos (e.g. turf and macroalgae) to reduce BCM proliferation on coral reefs.
ISSN: 1932-6203

hal-01159626
https://hal-univ-perp.archives-ouvertes.fr/hal-01159626
https://hal-univ-perp.archives-ouvertes.fr/hal-01159626/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01159626/file/journal.pone.0125445.pdf
DOI : 10.1371/journal.pone.0125445

Résumé : Les réseaux de capteurs constituent un axe de recherche très fertile ces dernières années. Cette technique se développe dans différents domaines comme l'environnement, l'industrie, le commerce, la médecine, l'armée, etc. Les réseaux de capteurs sont difficiles à concevoir parce qu'ils sont fortement contraints en énergie et que tous les éléments ont potentiellement une influence sur la durée de vie du système. Nous proposons un outil permettant l'aide au bon paramétrage et aux choix de paramètres optimaux pour la stabilité des applications.Dans cette thèse, nous nous sommes intéressés à deux problématiques : une classification des paramètres pour un outil d'aide à la décision pour la configuration d'un réseau de capteurs et la seconde, un outil de test de conformité du système dans un environnement réel. Le document est divisé en deux parties où la première partie est un état de l'art de différents protocoles existants et la deuxième partie décrit notre contribution dans ces deux problématiques.Dans la première contribution, nous avons analysé l'impact de la couverture radio puis de la topologie sur les performances d'un réseau de capteurs. Nous étudions le taux de perte et le niveau d'énergie pour en déduire la stabilité d'une application. Puis nous avons proposé une étude menant à une classification pour notre outil d'aide à la décision. Notre classification est basée sur une étude de divers paramètres de la couche MAC, physique, protocole de routage, nombre de nœuds et type d'application.Dans la deuxième contribution, nous nous sommes focalisés sur une approche pragmatique permettant de tester la conformité d'un réseau de capteurs dans un environnement réel. Pour tester la conformité dans un environnement réel, nous proposons une architecture d'exécution de test sur un réseau de capteurs réel. Ceci dans un but d'assurer un niveau correct de conformité et la stabilité de celui-ci durant son fonctionnement.
Wireless sensor networks is one of the hotest research topic in the last few years. This technology can be applied for different fields such as environment, industry, trading, medicine, military etc. Wireless sensor networks are hard to conceive because they require a lot of energy and because each of its component may have an influence on the lifetime of the whole system. What we suggest is a tool allowing to choose the correct and optimal parameters for the reliability of the applications.In this thesis, we focused on two major problems : firstly, a classification of the parameters for a tool allowing to make decisions about the configuration of a wireless sensors network, and secondly, a tool testing the compliance of the system with a real environment. The document is divided into two parts : the first part states the different protocols that exist, and the second part describes our contributions to those topics.In the first contribution, we analyzed how influential the radio cover and the network topology are on the network performances. Then, we deduced from the study of the loss rate and of the level of energy, the reliability of the application. Next, we suggested a study leading to a classification for our decision making tool. For this classification, we studied various parameters related to the MAC layer, the Physical layer, the network layer, the application layer the number of nodes involved in the network.In the second contribution, we adopted a pragmatic approach so we could test the conformity of a wireless sensors network in a real environment. In order to test its conformity in a real environment, we suggested a structured test execution on a real wireless sensor network. This task has been suggested in order to check the conformance level of the network while it was working.

http://www.theses.fr/2012AGUY0586/document

Éditeur(s) : HAL CCSD
Résumé : International audience
Metamorphic soles correspond to m to 500 m thick highly strained metamorphic rock units found beneath myloniticbanded peridotites at the base of large-scale ophiolites, as exemplified in Oman. Metamorphic soles aremainly composed of metabasalts deriving from the downgoing oceanic lithosphere and metamorphosed up togranulite-facies conditions by heat transfer from the mantle wedge. Pressure–temperature peak conditions areusually estimated at 1.00.2 GPa and 800100ºC. The absence of HP–LT metamorphism overprint implies thatmetamorphic soles have been formed and exhumed during subduction infancy. In this view, metamorphic soleswere strongly deformed during their accretion to the mantle wedge (corresponding, now, to the base of the ophiolite).Therefore, metamorphic soles and banded peridotites are direct witnesses of the dynamics of early subductionzones, in terms of thermal structure, fluid migration and rheology evolution across the nascent slab interface.Based on fieldwork and EBSD analyses, we present a detailed (micro–) structural study performed on samplescoming from the Sumeini window, the better-preserved cross-section of the metamorphic sole of Oman. Largedifferences are found in the deformation (CPO, grain size, aspect ratio) of clinopyroxene, amphibole and plagioclase,related to mineralogical changes linked with the distance to the peridotite contact (e.g., hardening due to theappearance of garnet and clinopyroxene).To model the incipient slab interface in laboratory, we carried out 5 hydrostatic annealing and simple-shear experimentson Griggs solid-medium apparatus. Deformation experiments were conducted at axial strain rates of 10-6s-1. Fine-grained amphibolite was synthetized by adding 1 wt.% water to a (Mid-Ocean Ridge) basalt powder asa proxy for the metamorphic sole (amphibole + plagioclase + clinopyroxene garnet assemblage). To synthetizegarnet, 2 experiments were carried out in hydrostatic conditions and with deformation at 800C with confiningpressure of 2 GPa. Another simple-shear experiment has been carried out at 800C and 1 GPa with fined-grainednatural garnet. With the aim of mimicking the early slab interface (between the metamorphic sole and bandedperidotites at the base of the ophiolite), 2 simple-shear deformation experiments with 2 layers have been carriedout at 800C and confining pressure of 1 GPa. The bottom layer was made of hydrated basalt powder and the toplayer was made of olivine.Fined-grained garnet-free amphibolite is significantly weaker than dunite but the appearance of harder mineralsin the amphibolite (garnet and clinopyroxene) has major implications on its rheological evolution. These resultsallow liking field observations of strain localization at the interface to the metamorphic sole formation
European Geosciences Union General Assembly 2016
Vienne, Austria

insu-01309394
https://hal-insu.archives-ouvertes.fr/insu-01309394

Éditeur(s) : HAL CCSD
Résumé : International audience
To study social health inequalities, contextual data may constitute an appropriate alternative to individual socioeconomic characteristics, often hard to retrieve. Indices can be used to summarize the multiple dimensions of the neighborhood socioeconomic status. The main objectives of this work are to develop a statistical procedure to create a neighborhood socioeconomic index and to investigate the influence of the clustering method of the deprivation index on the measure of health inequalities. Our study setting is composed of three major French metropolitan areas: Lille, Lyon and Marseille. The statistical unit is the French census block. The methodology uses several successive principal components analyses to select variables and create the index. Deprivation categories are drawn with hierarchical clustering on principal components. Twenty socioeconomic variables are selected in the neighborhood deprivation index. An optimal clustering obtained by HC is in three classes and the clusters are ordered along the first axis of the PCA.
SFDS - 44èmes journées de Statistique - 2012
Bruxelles, Belgium

hal-00734769
https://hal.archives-ouvertes.fr/hal-00734769
https://hal.archives-ouvertes.fr/hal-00734769/document
https://hal.archives-ouvertes.fr/hal-00734769/file/submission_44.pdf

Éditeur(s) : HAL CCSD Taylor & Francis: STM, Behavioural Science and Public Health Titles
Résumé : International audience
The dislocation microstructures in a single crystal of olivine deformed experimentally in uniaxial compression at 1090 °C and under a confining pressure of 300 MPa, have been investigated by transmission electron tomography in order to better understand deformation mechanisms at the microscale relevant for lithospheric mantle deformations. Investigation by electron tomography reveals microstructures, which are more complex than previously described, composed of and dislocations commonly exhibiting 3D configurations. Numerous mechanisms such as climb, cross-slip, double cross-slip as well as interactions like junction formations and collinear annihilations are the source of this complexity. The diversity observed advocates for microscale deformation of olivine significantly less simple than classic dislocation creep reported in metals or ice close to melting temperature. Deciphering mechanism of hardening in olivine at temperatures where ionic diffusion is slow and is then expected to play very little role is crucial to better understand and thus model deformation at larger scale and at temperatures (900–1100 °C) highly relevant for the lithospheric mantle.
ISSN: 1478-6443

hal-01667146
https://hal.archives-ouvertes.fr/hal-01667146
DOI : 10.1080/14786435.2017.1367858

Éditeur(s) : HAL CCSD
Résumé : International audience
Tin mineralization in Achmmach deposit (NE of Moroccan Central Massif) is associated with tourmaline-rich alteration halos and faults, within N70 shear zones, hosted in sandstones and metapelites of the Upper Visean-Namurian. Such deposits were reported as late-Variscan in age and related to the emplacement of late orogenic granite not outcropping in the studied area.From field constraints, it appears that the late Variscan phase is marked by a transition from transpression to extension with conditions of deformation evolving from ductile to brittle environments. During the transpressive phase (horizontal shortening direction roughly trending E-W), pervasive tourmaline is deposited under the form of metasomatic halos around fractures in the upper levels relative to the deep batholith. This hydrothermal activity is coeval with ductile shear zones within a large corridors trending N70. Tourmaline-rich alteration appears as a hardening stage contributing to the modification of the tectonic style of rocks. Thereafter, a strong brecciation occurs in response of re-using and re-opening of the strike-slip structure. The result is (1) the formation of dextral (N070, N020) and sinistral (N120) shears, and (2) the circulation of fluids within early tourmalinites and formation of tourmaline-rich breccia. Subsequently, during the late orogenic extensional phase, tourmalinite breccias reopened as normal faults acting as overpressure fluid pathways for developing other breccias and veins. Such event is marked by deposition of tin mineralization i.e., cassiterite followed by sulphides, and then fluorite and carbonates at the end.From analysis of the shear-zone structure and superimposition of tourmalines and tin mineralization in the same structures, it is possible to suggest a structural control continuum. Such control is well expressed during metasomatism and deposition of hydrothermal tourmaline under the transpressive phase. Thereafter, under the extensive phase allowing open-space, tin-mineralization were trapped.This study has been supported by AI MA/09/210
24ème RST
Pau, France

insu-01546927
https://hal-insu.archives-ouvertes.fr/insu-01546927

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
In addition to dietary exposure, children are exposed to metals via ingestion of soils and indoor dust, contaminated by natural or anthropogenic outdoor and indoor sources. The objective of this nationwide study was to assess metal contamination of soils and dust which young French children are exposed to. A sample of 484 children (6 months to 6 years) was constituted in order to obtain representative results for young French children. In each home indoor settled dust was sampled by a wipe in up to five rooms. Outdoor playgrounds were sampled with a soil sample ring (n=315) or with a wipe in case of hard surfaces (n=53). As, Cd, Cr, Cu, Mn, Pb, Sb, Sr, and V were measured because of their potential health concern due to soil and dust ingestion. The samples were digested with hydrochloric acid, and afterwards aqua regia in order to determine both leachable and total metal concentrations and loadings by mass spectrometry with a quadrupole ICP-MS. In indoor settled dust most (total) loadings were below the Limit of Quantification (LOQ), except for Pb and Sr, whose median loadings were respectively 9 and 10 μg/m². The 95th percentile of loadings were 2 μg/m² for As, <0.8 for Cd, 18 for Cr, 49 for Cu, <64 for Mn, 63 for Pb, 2 for Sb, 56 for Sr, and <8 for V. Median/95th percentile of loadings in settled dust on outdoor playgrounds were 2/16, <0.8/1.3, 17/53, 49/330, 99/424, 32/393, 2/13, 86/661 and 10/37 μg/m² for As, Cd, Cr, Cu, Mn, Pb, Sb, Sr, and V respectively. In outdoor playground soil median/95th percentile of concentrations (μg/g) were 8/26, <0.65/1, 25/52, <26/53,391/956, 27/254, 0.7/4, 54/295, 23/57 for As, Cd, Cr, Cu, Mn, Pb, Sb, Sr, and V respectively. These results are comparable with those observed in other countries. Because of their representative nature, we can assess children's exposures to these metals via soil and dust and the associated risks in urban and rural environments. Ratios of leachable/total concentrations and loadings, calculated on >LOQ measurements, differed among metals. To a lesser extent, they were also affected by type of matrix, with (except for Cd) a greater leachability of dust (especially indoor) compared to soils.
ISSN: 0160-4120

hal-00732136
https://hal.archives-ouvertes.fr/hal-00732136
PUBMED : 22613504
DOI : 10.1016/j.envint.2012.04.010

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Despite the dramatic reductions in children's blood lead levels (BLLs), there is considerable evidence that low-level lead exposure is associated with intellectual deficits and behavioral problems, without apparent threshold. There are limited data, however, about the contribution of residential sources of lead to contemporary children's blood lead levels. The aim of this study is to calculate the contributions of residential sources of lead to assess the potential impact of setting new standards for lead levels in residential dust, soil and water. We enrolled 484 French children aged from 6 months to 6 years, and collected data on social, housing and individual characteristics. Lead concentrations in blood and environmental samples (water, soils, and dusts) were measured using inductively coupled plasma mass spectrometry. Data were analyzed using a multivariate generalized additive model accounting for the sampling design and the sampling weights. We found that exceedingly low concentrations of lead in dust, soil and water were significant predictors of children's BLLs, after adjustment for potential confounding variables. Lead-contaminated floor dust was the main source of lead in blood. BLLs (GM: 14μg/L) increased by 65%, 13%, 25%, and 5% when lead content in floor dust, loose soil, hard soil and water increased from their 25th percentile to their 95th percentile, respectively. We also observed that the steepest increase in BLLs occurred at the lowest levels of lead-contaminated floor dust, which indicates that lead contamination should be kept as low as possible. Impact of different possible standards on children's BLLs was also tabulated and indicated that unless standards are set low, they will only benefit a small proportion of children who have the highest exposures.
ISSN: 1438-4639

inserm-00821999
http://www.hal.inserm.fr/inserm-00821999
DOI : 10.1016/j.ijheh.2013.02.007
PUBMED : 23528234

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Active faults from the Campo de Dalías (SE Betic Cordillera) allow us to constrain the deformation styles involved in the development of segmented oblique-slip faults. This sector constitutes the widest outcrop of Plio-Quaternary sediments in the northern boundary of the Alboran Sea. It has emerged since the Late Pliocene, and therefore provides recent deformation markers that are not disturbed by erosive processes. The faults started to grow during the Pleistocene, reactivating previous hybrid joints, with a normal-dextral slip. We present a detailed map of the largest fault in the area, the Loma del Viento fault, comprising six onshore segments. Based on field work and aerial photography, the distributions of the contiguous joints have been mapped, and the joints reactivated as faults are identified. Some of these fault segments are hard-linked, and fault slip enhances toward the linkage sectors between them with associated sedimentary depocenters. An electrical tomography profile reveals the wedge geometry of a unit of Pleistocene conglomerates and red silts that were coevally deposited during the fault movement. Long-term slip rate in the central part of the fault is estimated at 0.07 ± 0.03 mm/y. In addition, a seismic crisis nucleated close to the Loma del Viento fault during November 2010 was recorded. Moment tensor analysis of the two mainshocks (Mw 3.5 and 4.2) provides a focal solution indicating a N120°E striking right-lateral strike-slip fault. The corrugated morphology of the Loma del Viento fault may have influenced its seismic behavior. Some of the fault segments are oblique to the general motion of the fault. These oblique segments would provide higher resistance against the general fault motion and could lock the fault, leading to accumulate elastic energy.
ISSN: 0040-1951

hal-00750357
https://hal.archives-ouvertes.fr/hal-00750357
DOI : 10.1016/j.tecto.2011.12.001

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : In the Sicilian fisheries, the swordfish (Xiphias gladius, Linnaeus 1758), caught from March to December with several gears which vary according to season, represents one of the most important economic resources. The size composition changes depending on the gear used, the way it is operated, the fishing area and season. The gears used for swordfish fishing (long-lines "for swordfish", drift-nets, harpoons as operated by typical boats named "feluche") mainly catch adult specimens. From August to December, a high number of very young swordfish specimens (1.5 to 4.5 kg) is also caught as by-catch during the albacore (Thunnus alalunga, Bonnaterre 1788) fishing which is carried out by a special long line and hooks only 3 cm long. It was observed that in the same season, fishing areas and with boats of similar type, the fishing of dolphin-fish (Coryphaena hippurus, Linnaeus 1758), using Fish Aggregating Devices (FADs) and purse seine, is hardly practised in spite of the resource availability swordfish. With the present work, which can be regarded as an initial approach to the problem of diversifying and managing fishing effort of swordfish, albacore and dolphin-fish, their fisheries are examined and discussed, not overlooking the economic aspect, by considering weather a reallocation of fishing effort among the previously said resources might avert the risk of swordfish stock depletion.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15299/12659.pdf
http://archimer.ifremer.fr/doc/00042/15299/

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
Résumé :   Diffusion du document : INRA Antilles-Guyane, UMR ECOFOG, 97387 Kourou, Guyane (France) Diplôme : Master Recherche
il s'agit d'un type de produit dont les métadonnées ne correspondent pas aux métadonnées attendues dans les autres types de produit : DISSERTATION
The gravitropic reaction is a fundamental phenomenon in the life of the young trees in under-storey of a tropical rain forest. It enables them to preserve a growth in height even after a fall of remains or a wind fallen wood had leaning them. This reaction passes mainly by the differentiation of reaction wood and the offsetting of the radial growth. The gravitropic reaction is also under the control of various parameters such as the diameter of the stems, the hardness of wood, or masses they carried. The tropical rain forest contains a great specific diversity and ecological strategies. In this work we seek to know if this diversity is reflected in the strategies of recovery of the species in particular on a level of efficiency of reaction. We compared eight species of tropical rain forest with various ecological behaviours. We studied their changes in form in the course of time, as to their growth. We showed that there are indeed interspecific differences in the gravitropic reaction. Some behaviours are specific to some species. We also showed that for the majority of the species, the deformation energy is strongly correlated with the relative growth of the species.
Le redressement gravitropique est un phénomène fondamental dans la vie des jeunes arbres en sous-bois de forêt tropicale. Il leur permet de conserver une croissance en hauteur même après avoir subi la chute de débris ou même un chablis ayant conduit à leur inclinaison. Ce redressement passe principalement par la différentiation de bois de réaction et l’excentrement de la croissance radiale. Le redressement gravitropique est également sous le contrôle de différents paramètres tels que le diamètre des tiges, la dureté du bois, ou les masse portées. La forêt tropicale humide contient une grande diversité spécifique et de stratégies écologiques. Dans ce travail nous cherchons à savoir si cette diversité se reflète dans les stratégies de redressement des espèces notamment au niveau de l’efficience de la réaction. Nous avons comparé huit espèces de forêt tropicale humide avec différents comportements écologiques. Nous avons étudié leurs changements de forme au cours du temps, ainsi que leur croissance. Nous avons réussi à montrer qu’il existe effectivement des différences interspécifiques de redressement. Des comportements particuliers à certaines espèces ont pu être dégagés. Nous avons également montré que pour la majorité des espèces, l’énergie de déformation est fortement corrélée à la croissance relative de l’espèce.
https://hal.archives-ouvertes.fr/hal-01189172

hal-01189172
https://hal.archives-ouvertes.fr/hal-01189172
PRODINRA : 11396

Éditeur(s) : HAL CCSD
Résumé : One of the major challenges in forest ecology is to understand the ecology, physiology and potential responses of the> 250000 species of vascular plants of the planet through the categorization of this diversity into functional groups. This approach is essentially based on functional traits analysis, but few investigations were made in tropical areas. The aim of this study was to determine functional groups in two contrasted tropical ecosystems, dry (DF) and mountain rain (MRF) forest (respectively rainfall of 1 200 mm/year and 10 000 mm/year). Guadeloupe Island in FWI presents both these ecosystems spread over less 100 km. In a first time, we developed an original species typology based on 7 "soft" traits, easy to measure (stomatal density, leaf trichom density, chlorophyll content, leaf nitrogen content, specific leaf area, wood density, leaf area, plant height). The method was based on principal component analysis (PCA) and agglomerative hierarchical clustering (AHC) applied to these traits measured at the individual level (Blazy et al., 2009). In a second time, we evaluated the relevance of these soft trait-based groups compared to a typology based on 5 "hard" ecophysiological traits, more costly to quantify but with higher functional significance (difference between predawn and minimum leaf water potential, stomatal conductance, maximal carbon assimilation rate, leaf water potential at 90% of loss of stem hydraulic conductivity). When performed on the dominant canopy species in DF and MRF (a total of 13 species and 60 mature individuals), the typological approach based on soft traits seems relevant to discriminate groups with a distinct functional reality. Through both ecosystems, we obtained 4 homogenous groups. Two were exclusively composed by DF's or MRF's species, indicating that a functional strategy can be linked to specific environmental conditions. The two other groups showed a mix of DF and MRF species indicating that different functional strategies can coexist in the same environment. These mixed groups seem distinct by their ecophysiological features, particularly in term of hydraulic characteristics. One group was composed by drought tolerant species, water spender species, with a high xylem embolism resistance, whereas the second one was composed by water saver species, less resistant to embolism. Therefore, a determination of functional groups based on soft traits could be useful to model ecosystem's responses to environmental changes on a global scale.
Book of Abstracts - isem 2013 - Ecological Modelling for Ecosystem Sustainability
Toulouse, France

hal-00964668
https://hal.archives-ouvertes.fr/hal-00964668

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The analysis of three cataclastic band sets from Provence (France) reveals that the band density, their conjugate angles, their ratio of shear displacement to compaction, and the amount of cataclasis within the bands differ and can be expressed as functions of tectonic setting and petrophysical properties. We identify (1) a dense and closely spaced network of shear-enhanced (reverse) compaction bands; (2) a regularly spaced less dense network of reverse compactional shear bands; and (3) a localized network of normal shear bands. The field data show that strain localization is favored in an extensional regime and is characterized by shear bands with a large shear to compaction ratio and a small conjugate band angle. In contrast, distributed strain is favored in a contractional regime and is characterized by compactional bands with a low ratio of shear to compaction and a large conjugate band angle. To explain the mechanical origin of this strain localization, we quantify the yield strength and the stress evolution in extensional and contractional regimes in a frictional porous granular material. We propose a model of strain localization in porous sands as a function of tectonic stresses, burial depth, material properties, strain hardening and fluid pressure. Our model suggests that stress reduction, inherent to extensional regime, favors strain localization as shear bands, whereas stress increase during contraction favors development of compactional bands.
ISSN: 0191-8141

hal-00856921
https://hal.archives-ouvertes.fr/hal-00856921
DOI : 10.1016/j.jsg.2012.11.011

Éditeur(s) : HAL CCSD
Résumé : International audience
Until the end of the 20th century, heritage was mainly defined in the Caribbean, as in the entire world, by an european conception (linked with the formation of national identities), founded on the value of tangible heritage (rare, ancient objects, monuments and materials) as an historic proof of the value of cultures and peoples. Poets in the Caribbean hardly criticize this evidence that contributed to inferiorized people. Memory and imagination played a central role in the building of a Caribbean cultural identity. Poets tried to show how the common could rise from different patterns, diversity instead of unity, creation instead of fixity. Nevertheless, In the 21st century, frameworks are not available to deal with Caribbean heritage in its diversity (monuments, material, natural and intangible...) and complexity whereas it constitute a challenge for a sustainable society and can play a fundamental role in education as in tourism.
Jusqu'à la fin du XXe siècle, le patrimoine dans la Caraïbe comme ailleurs dans le monde, répondait principalement à une conception européenne (liée à la formation des identités nationales) fondée sur la valeur positive du patrimoine matériel comme preuve historique de la valeur des cultures et des peuples. Les poètes caribéens ont déconstruit ce cadre, instrument de l'infériorisation des individus. La mémoire et l'imagination ont joué un rôle central dans la construction d'une identité culturelle caribéenne. Ils ont tenté de montrer que le commun pouvait émerger de modèles différents, opposant à l'unique, le divers et à la fixité, la création. Cependant, au XXIe siècle, la Caraïbe ne dispose pas d'un cadre pour traiter son patrimoine dans sa diversité (patrimoine matériel, immatériel, naturel) et sa complexité alors que le patrimoine constitue un défi pour le développement durable des sociétés et peut jouer un rôle fondamental dans l'éducation et le tourisme.
Caribbean Studies Association annual conference
Port-au-Prince, Haiti

hal-01612909
https://hal.univ-antilles.fr/hal-01612909

Éditeur(s) : HAL CCSD PeerJ
Résumé : International audience
The tiger shark Galeocerdo cuvier (Carcharhinidae) is a large elasmobranch suspected to have, as other apex predators, a keystone function in marine ecosystems and is currently considered Near Threatened (Red list IUCN). Knowledge on its ecology, which is crucial to design proper conservation and management plans, is very scarce. Here we describe the isolation of eight polymorphic microsatellite loci using 454 GS-FLX Titanium pyrosequencing of enriched DNA libraries. Their characteristics were tested on a population of tiger shark (n = 101) from Reunion Island (SouthWestern Indian Ocean). All loci were polymorphic with a number of alleles ranging from two to eight. No null alleles were detected and no linkage disequilibrium was detected after Bonferroni correction. Observed and expected heterozygosities ranged from 0.03 to 0.76 and from 0.03 to 0.77, respectively. No locus deviated from Hardy-Weinberg equilibrium and the global F IS of the population was of 0.04 NS. Some of the eight loci developed here successfully cross-amplified in the bull shark Carcharhinus leucas (one locus), the spinner shark Carcharhinus brevipinna (four loci), the sandbar shark Carcharhinus plumbeus (five loci) and the scalloped hammerhead shark Sphyrna lewini (two loci). We also designed primers to amplify and sequence a mitochondrial marker, the control region. We sequenced 862 bp and found a low genetic diversity, with four polymorphic sites, a haplotype diversity of 0.15 and a nucleotide diversity of 2 × 10 −4 .
ISSN: 2167-8359

hal-01317961
https://hal.archives-ouvertes.fr/hal-01317961
https://hal.archives-ouvertes.fr/hal-01317961/document
https://hal.archives-ouvertes.fr/hal-01317961/file/Pirog_2016PeerJ_microsat_tiger_shark.pdf
DOI : 10.7717/peerj.2041

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
Torsion experiments (inline image =3 × 10−4 s−1) were performed to investigate the large strain (γmax = 15) rheology on quartz-muscovite aggregate as analogue to pelitic rocks undergoing melting and crystallization during deformation at 300 MPa confining pressure and 750°C temperature. Microstructures reveal four distinct but gradational stages of crystal-melt interactions during deformation--(a) solid state deformation, (b) initiation and domination of partial melting, (c) simultaneous partial melting and crystallization, and (d) domination of crystallization. The microstructural stages are linked to the rheology of the deforming samples. Partial melting starts at relatively low finite shear strains (γ = 1-3) showing approximately 60% strain softening. At γ = 4-10 the partially molten bulk material shows a steady state flow at low stress. Further crystallization of new crystals at the expense of melt between γ = 10 and 15 causes weak strain hardening until the material fails by developing brittle fractures. The stress exponent (n), calculated at γ = 1, 5, and 10, increases from ∼ 3 to ∼ 43, indicating a transition from power to power law breakdown or exponential flow of the bulk system. Hydrostatic experiments for equivalent times and conditions of the torsion experiments were also conducted to evaluate the reaction kinetics and microstructures under static conditions. The new experimental data establish that partially molten rock does not flow according to a constant strain rate-dependent power law (steady state) rheology. The rheological transition from strain rate sensitive to strain rate insensitive flow is interpreted as a function of melt-crystal ratio, their mutual interactions, and the evolution of microstructures in the partially molten rock.
ISSN: 0148-0227

hal-01053709
https://hal.archives-ouvertes.fr/hal-01053709
DOI : 10.1002/2013JB010777