Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Correlations between major and minor transition elements in tectonically emplaced orogenic peridotites have been ascribed to variable degrees of melt extraction and melt–rock reaction processes, leading to depletion or refertilization. To elucidate how such processes are recorded in the subcontinental lithospheric mantle, we processed a large geochemical dataset for peridotites from the four tectono-metamorphic domains of the Beni Bousera orogenic massif (Rif Belt, northern Morocco). Our study reveals that variations in bulk-rock major and minor elements, Mg-number and modal mineralogy of lherzolites, as well as their clinopyroxene trace element compositions, are inconsistent with simple partial melting and mainly resulted from different reactions between melts and depleted peridotites. Up to 30% melting at < 3 GPa and cryptic metasomatism can account for the geochemical variations of most harzburgites. In Grt–Sp mylonites, melting and melt–rock reactions are masked by tectonic mixing with garnet pyroxenites and subsolidus re-equilibration. In the rest of the massif, lherzolites were mostly produced by refertilization of a refractory protolith (Mg-number ∼ 91, Ol ∼ 70%, Cpx/Opx = 0·4) via two distinct near-solidus, melt–rock reactions: (1) clinopyroxene and orthopyroxene precipitation and olivine consumption at melt/rock ratios <0·75 and variable mass ratio between crystallized minerals and infiltrated melt (R), which are recorded fairly homogeneously throughout the massif; (2) dissolution of orthopyroxene and precipitation of clinopyroxene and olivine at melt/rock ratios ≤1 and R = 0·2–0·3, which affected mainly the Ariègite–Seiland and Seiland domains. The distribution of secondary lherzolites in the massif suggests that the first refertilization reaction occurred prior to the differentiation of the Beni Bousera mantle section into petro-structural zones, whereas the second reaction was associated with the development of the tectono-metamorphic domains. Our data support a secondary, refertilization-related origin for most lherzolites in orogenic peridotite massifs.
ISSN: 0022-3530

hal-01526901
https://hal.archives-ouvertes.fr/hal-01526901
DOI : 10.1093/petrology/egx003

Éditeur(s) : HAL CCSD Université des Antilles
Résumé : International audience
Considering the increasing importance of the tourist mobilities worldwide, the questioning on the interrelationships between tourism and natural resources is more current more than ever. Tourism is a powerful vehicle of territory transformations which must be comprehended though flows, practices, consumptions. It means taking of the complexity of tourist system and of identifiyng the economic, social and environmental stakes linked to the use and the exploitation of the biodiversity by this activity.
Le questionnement sur les interactions entre le tourisme et les ressources naturelles est plus que jamais d’actualité compte tenu de l’importance croissante des mobilités touristiques à travers le monde. Le tourisme est un puissant vecteur de transformation du territoire qui doit être appréhendé à travers les flux, les pratiques, les consommations. Il s’agit de prendre la mesure de la complexité du système touristique et d’identifier les enjeux économiques, sociaux et environnementaux liés à l’utilisation et l’exploitation de la biodiversité par cette activité.
ISSN: 1779-0980

Droits : http://creativecommons.org/licenses/by-nc/
hal-01625317
https://hal.archives-ouvertes.fr/hal-01625317

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Cet article étudie l’évolution de la Consommation énergétique des ménages à La Réunion entre 1980 et 2005, en mettant l’accent sur le domaine de la consommation domestique d’électricité. Il montre que cet espace, autonome sur un plan énergétique au début des années 1980, a connu une dépendance de plus en plus forte vis-à-vis des approvisionnements en ressources fossiles durant les deux dernières décennies, sous la pression des mutations démographiques, économiques et sociologiques engagées. Depuis le début des années 2000, sous l’impulsion des politiques publiques, essentiellement fiscales, La Réunion s’engage dans le développement des énergies renouvelables, essentiellement le photovoltaïque, en s’affichant en tête des régions françaises et européennes dans la maîtrise de cette production énergétique.
This article aims at studying the evolution of the domestic consumption of energy in Reunion island between 1980 and 2005 (electricity consumption). It shows that this area which reached its energetic autonomy at the beginning of the 80’s has known a strong dependency from fossil resources for the last two decades, due to the increasing pressures of demographic, economic and sociological factors. Since the beginning of the 2000’s, as a result of public policies impulsion (mainly fiscal policies), Reunion island has developed the use of renewable resources (essentially photovoltaic). It tends to be now one of the first French and European regions mastering this energy production process.
Réunion

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.3519
http://journals.openedition.org/etudescaribeennes/3519

Éditeur(s) : HAL CCSD Cushman Foundation for Foraminiferal Research
Résumé : International audience
This study proposes a new method for fast and inexpensive extraction of a large number of living foraminifera for laboratory cultures. The method is a significant improvement over current extraction methods, which are highly time-consuming. Several treatments were designed to test the method. Sediment bearing foraminifera from Brouage Mudflat (Atlantic coast of France) was washed through a 50-µm sieve and distributed in glass Petri dishes with 20, 40 and 80 specimens of Hydrobia ulvae, a common gastropod from European intertidal mudflats. As a control experiment, one dish was treated similarly but maintained without Hydrobia. After two days, most of the sediment in the Hydrobia treatments was compacted into small cylindrical gastropod feces and the tests of living benthic foraminifera (Ammonia tepida and Haynesina germanica) were clean and easily visible. Additional experiments showed that the foraminifera were not ingested by Hydrobia ulvae, and could be picked quickly and easily.
ISSN: 0096-1191

hal-01248034
https://hal.archives-ouvertes.fr/hal-01248034
https://hal.archives-ouvertes.fr/hal-01248034/document
https://hal.archives-ouvertes.fr/hal-01248034/file/rossignol%20et%20al%202007.pdf
DOI : 10.2113/gsjfr.37.1.8

Éditeur(s) : HAL CCSD Ecological Society of America
Résumé : Herbivory is viewed as a major driver of plant evolution and the mostimportant energy pathway from plants to higher trophic levels. Therefore, understandingpatterns of herbivory on plants remains a key focus in evolution and ecology. Theevolutionary impacts of leaf herbivory include altering plant fitness, local adaptation, theevolution of defenses, and the diversification of plants as well as natural enemies. Leafherbivory also impacts ecological processes such as plant productivity, communitycomposition, and ecosystem nutrient cycling. Understanding the impact of herbivory onthese ecological and evolutionary processes requires species-specific, as opposed tocommunity-level, measures of herbivory. In addition, species-specific data enables the use ofmodern comparative methods to account for phylogenetic non-independence. Althoughhundreds of studies have measured natural rates of leaf consumption, we are unaware of anyaccessible compilation of these data. We created such a data set to provide the raw dataneeded to test general hypotheses relating to plant–herbivore interactions and to test theinfluence of biotic and abiotic factors on herbivory rates across large spatial scales. A largerepository will make this endeavor more efficient and robust. In total, we compiled 2641population-level measures for either annual or daily rates of leaf herbivory across 1145 speciesof vascular plants collected from 189 studies. All damage measures represent naturaloccurrences of herbivory that span numerous angiosperm, gymnosperm, and fern species. Toenable researchers to explore the causes of variation in herbivory and how these mightinteract, we added information about the study sites including: geolocation, climateclassification, habitat descriptions (e.g., seashore, grassland, forest, agricultural fields), andplant trait information concerning growth form and duration (e.g., annual vs. perennial). Wealso included extensive details of the methodology used to measure leaf damage, includingseasons and months of sampling, age of leaves, and the method used to estimate percentagearea missing. We anticipate that these data will make it possible to test important hypothesesin the plant–herbivore literature, including the plant apparency hypothesis, the latitudinalherbivorydefense hypothesis, the resource availability hypothesis, and the macroevolutionaryescalation of defense hypothesis.
ISSN: 0012-9658

hal-01601627
https://hal.archives-ouvertes.fr/hal-01601627
DOI : 10.1890/13-1741.1
PRODINRA : 397136
PUBMED : 24870043

Éditeur(s) : HAL CCSD PeerJ
Résumé : International audience
Understanding the role of predators in food webs can be challenging in highly diverse predator/prey systems composed of small cryptic species. DNA based dietary analysis can supplement predator removal experiments and provide high resolution for prey identification. Here we use a metabarcoding approach to provide initial insights into the diet and functional role of coral-dwelling predatory fish feeding on small invertebrates. Fish were collected in Moorea (French Polynesia) where the BIOCODE project has generated DNA barcodes for numerous coral associated invertebrate species. Pyrosequencing data revealed a total of 292 Operational Taxonomic Units (OTU) in the gut contents of the arc-eye hawkfish (Paracirrhites arcatus), the flame hawkfish (Neocirrhites armatus) and the coral croucher (Caracanthus maculatus). One hundred forty-nine (51%) of them had species-level matches in reference libraries (>98% similarity) while 76 additional OTUs (26%) could be identified to higher taxonomic levels. Decapods that have a mutualistic relationship with Pocillopora and are typically dominant among coral branches, represent a minor contribution of the predators' diets. Instead, predators mainly consumed transient species including pelagic taxa such as copepods, chaetognaths and siphonophores suggesting non random feeding behavior. We also identified prey species known to have direct negative interactions with stony corals, such as Hapalocarcinus sp, a gall crab considered a coral parasite, as well as species of vermetid snails known for their deleterious effects on coral growth. Pocillopora DNA accounted for 20.8% and 20.1% of total number of sequences in the guts of the flame hawkfish and coral croucher but it was not detected in the guts of the arc-eye hawkfish. Comparison of diets among the three fishes demonstrates remarkable partitioning with nearly 80% of prey items consumed by only one predator. Overall, the taxonomic resolution provided by the metabarcoding approach highlights a highly complex interaction web and demonstrates that levels of trophic partitioning among coral reef fishes have likely been underestimated. Therefore, we strongly encourage further empirical approaches to dietary studies prior to making assumptions of trophic equivalency in food web reconstruction. How to cite this article Leray et al. (2015), Metabarcoding dietary analysis of coral dwelling predatory fish demonstrates the minor contribution of coral mutualists to their highly partitioned, generalist diet. PeerJ 3:e1047
ISSN: 2167-8359

Droits : http://creativecommons.org/licenses/by/
hal-01174184
https://hal-univ-perp.archives-ouvertes.fr/hal-01174184
https://hal-univ-perp.archives-ouvertes.fr/hal-01174184/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01174184/file/peerj-1047.pdf
DOI : 10.7717/peerj.1047

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : Intraguild predation (IGP) is a type of biological interaction involving the killing and consuming of competing species that exploit similar and often limited resources. This phenomenon is widespread among a great variety of taxonomic groups and has already been reported for mosquito (Diptera: Culicidae) larvae. Moreover, the larvae of certain mosquito species of the tribe Sabethini have evolved modified mouthparts ending in rigid apical structures signaling their capacity to be effective intraguild predators. We assumed that IGP confers a selective advantage under severe competitive conditions by both providing an immediate energetic gain and reducing potential competition. Because potential competition is likely to increase with decreasing habitat size, we hypothesized that the proportion of species with modified mouthparts would increase in smaller aquatic habitats. We tested this hypothesis by examining the mosquito species naturally associated with phytotelmata of decreasing sizes in French Guiana. We show that the degree of specialization in mosquito-phytotelm associations is high, suggesting a long coevolutive process. Indeed, short-term interaction experiments confirmed that species with modified mouthparts are able to prey upon similarly-sized intraguild prey and are, thus, effective intraguild predators. In addition, these species are larger and associated with smaller phytotelmata than those with typical mouthparts. Moreover, below a certain threshold of phytotelm size, only species with modified mouthparts were present. These results show that IGP confers a selective advantage under severe competitive conditions and results from the coadaptation of mosquito species to their specific phytotelm habitat. The presence of functionally analogous structures in different mosquito genera also implies that IGP has emerged from convergent evolution in small phytotelmata.
ISSN: 0269-7653

hal-01603304
https://hal.archives-ouvertes.fr/hal-01603304
DOI : 10.1007/s10682-016-9862-3
PRODINRA : 405771

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The current design studies on sodium-cooled fast reactors (SFRs) are breaking with the past since they are guided by a new set of design criteria arising from the objectives of Generation IV reactors. The new safety requirements lead to designing reactors with breakeven breeding cores because in terms of reactivity control, they minimize the need to limit the consequences of an inadvertent control rod withdrawal event. Furthermore, as the reactivity control needs are low, a breakeven core enables the use of absorbing materials with reduced efficiency (natural boron, hafnium, etc.), which may be less costly than enriched boron. However, control rods designed with low absorbing materials may present the disadvantage of a nonnegligible loss of efficiency due to their consumption under irradn. This paper presents a methodol. to accurately calc. and to analyze the impact of this consumption on reactivity control.
ISSN: 0302-2927

hal-01088526
https://hal.archives-ouvertes.fr/hal-01088526
DOI : 10.13182/NSE13-59

Éditeur(s) : HAL CCSD
Résumé : International audience
OBJECTIVE: Contemporary pesticides, such as triazines or organophosphates, possess immunotoxic properties. We aimed to determine whether prenatal environmental exposure to these current-use pesticides was associated with otitis media (OM) during the first 2 years of life among children from the PELAGIE mother-child cohort. METHODS: The PELAGIE cohort enrolled 3421 women at the beginning of pregnancy in Brittany (France). At the 2-year follow-up, 1505 families completed a self-administered questionnaire, including the domestic use of pesticides and consumption of organic diet during pregnancy and occurrences of OM in the child. Two health outcomes were considered: at least one OM and recurrent OM (at least three). Multivariate logistic regression models that adjusted for known risk factors of OM were performed. Metabolites of triazine herbicides and organophosphate insecticides measured in urine collected before the 19th week of gestation (248 mothers) were considered in a subgroup analysis. Multiple imputation was used to handle missing values for the covariates. RESULTS: Children whose mothers reported an organic diet during pregnancy had a reduced risk of OM (at least one episode, p trend=0.01). No association was found between any outcome and residential proximity to crops. The presence in maternal urine of dealkylated triazine metabolites (OR=2.12 (1.01 to 4.47)) was positively associated with recurrent OM. CONCLUSIONS: To the best of our knowledge, this is the first work to suggest a positive association between prenatal exposure to current-use pesticides and the occurrence of parent-reported OM in young children
Occupational and Environmental Medicine

hal-01201944
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01201944
DOI : 10.1136/oemed-2015-103039
PUBMED : 26347056

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Growth hormone (GH) may stimulate water loss during exercise by activating sweating. This study investigated GH secretion and water loss during sequential cycling and running, taking postural changes into account. The two exercise segments had similar durations and were performed at the same relative intensity to determine their respective contributions to water loss and the plasma volume variation noted in such trials. Eight elite triathletes first performed an incremental cycle test to assess maximal oxygen consumption. Then, the triathletes performed one of two trials in randomized order: constant submaximal cycling followed by treadmill running (C 1 –R 2) or an inversed succession of running followed by cycling (R 1 –C 2). Each segment of both trials was performed for 20 minutes at ,75% of maximal oxygen consumption. The second trial, reversing the segment order of the first trial, took place two weeks later. During cycling, the triathletes used their own bicycles equipped with a profiled handlebar. Blood sampling (for GH concentrations, plasma viscosity and plasma volume variation) was conducted at rest and after each segment while water loss was estimated from the post-and pre-measures. GH increases were significantly lower in R 2 than C 2 (72.2650.1 vs. 164.06157 ng.ml 21 .min 21 , respectively; P,0.05). Water loss was significantly lower after C 1 –R 2 than R 1 –C 2 (11056163 and 12356153 ml, respectively; P,0.05). Plasma volume variation was significantly negative in C 1 and R 1 (26.1562.0 and 23.1665.0%, respectively; P,0.05), not significant in C 2 , and significantly positive for seven subjects in R 2 (4.0563.1%). We concluded that the lower GH increases in R 2 may have contributed to the smaller reduction in plasma volume by reducing sweating. Moreover, this lower GH response could be explained by the postural change during the transition from cycling to running. We recommend to pay particular attention to their hydration status during R 1 which could limit a potential dehydration during C 2 .
ISSN: 1932-6203

hal-01158212
https://hal.univ-antilles.fr/hal-01158212
DOI : 10.1371/journal.pone.0096145

Éditeur(s) : HAL CCSD Université des Antilles
Résumé : International audience
The Caribbean Sea is emblematic of the cruise, it is known for its international routes, scenic postcards touting the charms of the region. The analysis of the cruise industry will highlight some limits and contradictions of current development patterns. The product "cruise" has evolved considerably. It’s now the cruise ship itself (temple of consumption and enclave floating) that became the object of the Cruise, the “Destination” of the cruise line.The cruise is part of mass tourism. It’s characterized by its huge boats, rationalization and cost optimization in the context of a market increasingly globalized capital. All data that must be analyzed to understand recent developments in the cruise and repeated challenges to the host territories.
El Mar Caribe es un emblema de la travesía. Esta conocido por sus rutas internacionales, postales escénicas explicando en detalle los encantos de la región. El análisis de la industria de los cruceros pondrán de relieve algunos límites y contradicciones de los patrones actuales de desarrollo. El producto "crucero" ha evolucionado considerablemente. Ahora es el crucero en sí (el templo del consumo y el enclave flotante) que se convirtió en el objeto del Crucero, el Destino "de la línea de cruceros. El crucero es parte del turismo de masas. Se caracteriza por sus grandes barcos, la racionalización y optimización de costes en el contexto de un mercado de capitales cada vez más globalizado. Todos los datos que se deben analizar para comprender la evolución reciente en el crucero y constantes desafíos a los territorios de acogida.
La mer des Caraïbes est un espace emblématique de la croisière. Au-delà de la réputation mondiale de ses destinations, des cartes postales qui vantent les charmes de la région, l’analyse de l’industrie de la croisière permet de souligner certaines limites et contradictions des modalités de développement actuelles. Le produit « croisière » a considérablement évolué : désormais c’est le paquebot en lui-même (temple de la consommation et enclave flottante) qui est devenu la destination du croisiériste. Ouverture au tourisme de masse, gigantisme des bateaux, rationalisation et optimisation des coûts dans le cadre d’un marché de plus en plus globalisé et capitalistique sont autant de données qui doivent être analysées pour comprendre l’évolution récente de la croisière et les défis renouvelés pour les territoires d’accueil.
ISSN: 1779-0980

hal-01624772
https://hal.archives-ouvertes.fr/hal-01624772
DOI : 10.4000/etudescaribeennes.3843

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
In the southeastern corner of the Tyrrhenian basin, in the central Mediterranean Sea, a tight alignment of earthquakes along a well-defined Benioff zone marks one of the narrowest active trenches worldwide, where one of the last fragment of the former Tethys ocean is consumed. Seismic tomography furnishes snapshot images of the present-day position of this slab, and seismic anisotropy allows to reconstruct the past kinematics of the subduction process. Using seismic anisotropy fast directions as a proxy for the present and past mantle flow, we look backward for the seismic traces of the slab motion through the western-central Mediterranean mantle, from the starting locus of subduction toward its present day position. The result of combining independent data sets provides a coherent pattern of anisotropy that illustrates an example of slab rollback from its initiation point to its present-day position.
ISSN: 0012-821X

hal-01389115
http://hal.univ-reunion.fr/hal-01389115
http://hal.univ-reunion.fr/hal-01389115/document
http://hal.univ-reunion.fr/hal-01389115/file/Lucente_medit_EPSL2006_hal.pdf
DOI : 10.1016/j.epsl.2005.10.041

Éditeur(s) : HAL CCSD Elsevier
Résumé : We studied the evolution of the microstructure of ice-Ih during static recrystallization by stepwise annealing experiments. We alternated thermal annealing and electron backscatter diffraction (EBSD) analyses on polycrystalline columnar ice pre-deformed in uniaxial compression at temperature of −7 °C to macroscopic strains of 3.0–5.2. Annealing experiments were carried out at −5 °C and −2 °C up to a maximum of 3.25 days, typically in 5–6 steps. EBSD crystal orientation maps obtained after each annealing step permit the description of microstructural changes. Decrease in average intragranular misorientation at the sample scale and modification of the misorientation across subgrain boundaries provide evidence for recovery from the earliest stages of annealing. This initial evolution is similar for all studied samples irrespective of their initial strain or annealing temperature. After an incubation period ≥1.5 h, recovery is accompanied by recrystallization (nucleation and grain boundary migration). Grain growth proceeds at the expense of domains with high intragranular misorientations, consuming first the most misorientated parts of primary grains. Grain growth kinetics fits the parabolic growth law with grain growth exponents in the range of 2.4–4.0. Deformation-induced tilt boundaries and kink bands may slow down grain boundary migration. They are stable features during early stages of static recrystallization, only erased by normal growth, which starts after >24 h of annealing.
ISSN: 0191-8141

hal-01685644
https://hal.archives-ouvertes.fr/hal-01685644
DOI : 10.1016/j.jsg.2017.05.001

Éditeur(s) : HAL CCSD
Résumé : The presence of biological matter (biofilms) in deep geological sites for storage of, for instance, toxic elements or groundwater in aquifers was clearly proved. That biomass triggers physical and chemical processes which greatly modify the durability and the sustainability of the sites. These processes, mainly from oxidative/reductive reactions, are poorly understood. This is mainly due to the fact that former studies were done at the macroscopic level far away from the micrometric scale where relevant processes induced by bacteria take place. Investigations at microscopic level are needed. Thus, we developed an experimental set-up based on the combined use of optical microscopy (transmission), atomic force microscopy (AFM) and electrical and electro-chemical AFM microscopy (EC_AFM) in order to get simultaneous information on topographic and electro-chemical processes. The first highly sensitive step was to use AFM with biological samples in liquid environment: wepresent here a study about AFM imaging of living, moving or self-immobilized bacteria, in their genuine physiological liquid medium and in true in vivo conditions. No external immobilization protocol, neither chemical nor mechanical was needed. For the first time, the native gliding movements of Gram negative Nostoc cyanobacteria upon the surface were studied by AFM. AFM height and mechanical stiffness data were simultaneously acquired. From these, mechanical parameters, inner turgor pressure and Young modulus, were derived for different bacterial species (Anabaenopsis circularis, Rhodococcus wratislaviensis). Our study revealed that AFM imaging is thus possible on moving living species. These results open a large window on new studies of both dynamical phenomena of practical and fundamental interests such as the formation of biofilms and dynamic properties of bacteria in real physiological conditions. The second delicate step was to combine AFM and optical measurements with electrical ones. We mounted a new experimental set-up coupling real-time (i) monitoring of optical properties as the optical density (OD) evolution related to bulk bacterial growth in liquid or as the counting of number of bacteria adhering on the surface of the sample as well and (ii) electrical and electrochemical measurements. Furthermore, these results will shortly be applied to the optimized monitoring of the in-situ activity of bacteria consuming oil pollutants, following this way, in real-time, the bioremediation of an oilcontaminated soil (ANR ECOTECH_BIOPHY program).
La présence de matière biologique (biofilms) dans les sites de stockage géologique profond, d'éléments toxiques ou encore de l'eau potable des aquifères est maintenant clairement démontrée. Cette biomasse est à l'origine de processus physiques et chimiques qui modifient considérablement la durabilité et la pérennité des sites concernés. Ces processus, principalement de type oxydo-réductif, sont encore mal compris. Ceci est principalement dû aux méthodes d'investigation, principalement macroscopiques, loin de l'échelle micrométrique caractéristique des bactéries. Seules des études, basées sur des méthodes d'investigation locale, peuvent apporter les informations requises. Ainsi, nous avons développé un dispositif expérimental basé sur l'utilisation combinée de la microscopie optique (en transmission), la microscopie à force atomique (AFM) et la microscopie AFM en mode électrique et électrochimique (EC_AFM) afin d'obtenir des informations simultanées sur la topographie de l'échantillon et sur les processus électrochimiques à l'échelle des bactéries. La première étape sensible consistait à utiliser l'AFM sur des échantillons biologiques en milieu liquide: nous présentons ici les résultats de l'imagerie AFM en milieu liquide de plusieurs types de bactéries dans leurs conditions physiologiques naturelles (conditions in vivo). Aucun protocole d'immobilisation, ni chimique ni mécanique, n'a été nécessaire; et pour la première fois, les mouvements de reptation de cyanobactéries Nostoc ont été étudiés par l'AFM. Les études AFM ont permis d'acquérir des données topographiques mais aussi mécaniques : nous avons pu ainsi mesurer le module d'Young, la pression de turgescence de différentes souches bactériennes (Anabaenopsis circularis, Rhodococcus wratislaviensis). Cette étude complète, a révélé que l'imagerie AFM est donc possible sur des espèces vivantes en mouvement. Ces résultats ouvrent une grande fenêtre sur de nouvelles études d'intérêts tels que la formation de biofilms et les propriétés dynamiques de bactéries dans des conditions physiologiques réelles. La deuxième étape délicate était de combiner l'AFM aux mesures optiques et électriques. Nous avons développé un nouveau dispositif expérimental permettant (i) le suivi de l'évolution de la croissance bactérienne par la mesure des propriétés optiques comme la densité optique DO (pour le développement bactérien en volume - milieu planctonique) , ou l'analyse de l'image du substrat par comptage du nombre de bactéries sur la surface de l'échantillon (biofilm), et (ii) les mesures électriques et électrochimiques. L'ensemble de ces résultats sera prochainement appliqué au développement de nouveaux outils de surveillance d'une biodépollution de terrain contaminé par les hydrocarbures, par le suivi in situ et en temps réel de l'activité de bactéries dépolluantes (ECOTECH_BIOPHY ANR).
https://tel.archives-ouvertes.fr/tel-01044714

tel-01044714
https://tel.archives-ouvertes.fr/tel-01044714
https://tel.archives-ouvertes.fr/tel-01044714/document
https://tel.archives-ouvertes.fr/tel-01044714/file/theseDhahri2013.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Spinel (± plagioclase) peridotite xenoliths from the Tallante and Los Perez volcanic centres in the eastern Betics (SE Spain) range from depleted (clinopyroxene-poor) harzburgites to fertile (clinopyroxene-rich) lherzolites and orthopyroxene-free wehrlites. Significantly, only one harzburgite, which is depleted in heavy rare earth elements (HREE), retains the imprint of ca. 20% ancient melting of an original garnet lherzolite source. In contrast, REE abundances of other harzburgites and lherzolites from the eastern Betics have been increased by melt-rock reaction. The whole-rock and mineral compositions of these mantle rocks are largely controlled by three types of modal metasomatism: 1) common clinopyroxene-orthopyroxene addition and olivine consumption which increased FeOt, SiO2 and Al2O3, and decreased MgO compared to the refractory melting products; 2) subordinate orthopyroxene dissolution and precipitation of clinopyroxene and olivine, which led to higher FeOt and MgO and lower SiO2 than in common (orthopyroxene-rich) lherzolites; and 3) rare orthopyroxene consumption and olivine addition that caused higher FeOt and lower SiO2 compared to the original melting residues. These mineral modal and major element variations have been produced mostly by interactions with relatively FeOt-rich/SiO2-poor melts, likely derived from a peridotite-pyroxenite lithospheric mantle with a highly heterogeneous isotopic composition. Melting of the lithospheric mantle in the western Mediterranean was triggered by upwelling of the asthenosphere induced by back-arc extension in the Late Oligocene-Early Miocene. Trapping of small fractions of exotic melts in whole-rocks — likely the parental magmas of Miocene back-arc dykes that intruded the Betic crust — caused local disequilibrium between the trace element signatures and Pb isotopic compositions of clinopyroxene and whole-rock. Subsequent interaction with SiO2-undersaturated magmas, similar to the parental melts of the Pliocene alkali basalts that host the xenoliths, promoted orthopyroxene consumption and clinopyroxene-olivine enrichment at locations close to magma conduits, and finally generated orthopyroxene-free wehrlites. This event constitutes the last episode of the Cenozoic magmatic evolution of the westernmost Mediterranean which is recorded in the mantle xenoliths from the eastern Betics.
ISSN: 0024-4937

hal-01553092
https://hal.archives-ouvertes.fr/hal-01553092
DOI : 10.1016/j.lithos.2016.12.011

Éditeur(s) : HAL CCSD
Résumé : Background and objectives.[br/] Dairy propionibacteria are isolated from various ecological niches, including soil, grass, silage, rumen, raw milk and dairy plants, showing great adaptability and robustness. Used as ripening starters in Swiss type cheeses, these food grade bacteria are described as nutraceutical producers and they release into the external medium short chain fatty acids (SCFA), folic acid, cobalamin and the bifidogenic 1,4- dihydroxy-2-naphthoic acid (DHNA). These compounds are known to play a pivotal role in the modulation of intestinal physiology through diet. Considering the pro-apoptotic potential of some of these metabolites, we investigated the potential of dairy products fermented by the main species, Propionibacterium freudenreichii, to prevent colon carcinogenesis. Methods.[br/] We developed a new fermented milk. Taking advantage of milk fractions, high and stable populations of P. freudenreichii were obtained in this product. It was tested in vitro on gastric HGT-1 and colic HT-29 cells with respect to the typical hallmarks of apoptosis. In vivo, the fermented milk was evaluated in piglets with respect to general health parameters and in human microbiota-associated rats, treated or not with dimethylhydrazine (DMH), with respect to intestinal proliferation and apoptosis. Results. Fermented milk induced cell death in both gastric and colon cancer cells. Cellular and molecular characterization of cells dying in response to SCFA treatment revealed cell cycle arrest, drop in intracellular ATP, depolarization of mitochondria, translocation of key apoptosis proteins, processing of caspases and fragmentation of the nucleus. Interestingly, the new fermented milk was shown to potentiate the cytotoxic effect of molecules used in cancer chemotherapy. In accordance, it modulated expression of key apoptotic proteins. In vivo, the fermented milk was evaluated in piglets. Daily oral gavage led to high colic P. freudenreichii populations, to modulation of the intestinal microbiota and modulation of intestinal cytokines. Promotion of piglets’ growth also revealed general probiotic effects of fermented milk. Considering that propionibacteria were metabolically active in the intestine, we further investigated their impact on colon carcinogenesis (induced by dimethylhydrazine, DMH) in human microbiota-associated rats. Consumption of selected strains of propionibacteria resulted in enhanced apoptotic depletion of DMH damaged epithelial cells, yet had no effect on neither proliferation nor apoptosis in healthy rats. Conclusions and perspectives.[br/] These results open new perspectives in the field of colon cancer cells prevention and/or treatment. The synergy with pro-apoptotic chemotherapy molecules suggests that such a fermented product may be proposed as a food supplement to enhance the effects of anticancer treatments.
colloque international « Nutrition and Cancer : Hot topics from biology to public health issues »
Paris, France

hal-01190452
https://hal.archives-ouvertes.fr/hal-01190452
PRODINRA : 201853

Éditeur(s) : Soc Francaise D Ichtyologie
Résumé : The energy value of the main prey and the growth of juvenile hake in the Gulf of Lions were analysed to determine whether fish condition could be linked to difference in prey quality and resulted in growth difference. Large differences in energy content (15.6 to 23.6 kJ g(-1) DW) among prey types were recorded with low values found in amphipods and natantid shrimps, intermediate values in euphausiids and mysids, and high values in fish. High condition in juvenile hake was linked to the consumption of prey with high energy content. However, no difference in fish growth was observed by the analysis of otolith micro-increments.
Cybium (0399-0974) (Soc Francaise D Ichtyologie), 2012-06 , Vol. 36 , N. 2 , P. 323-328

Droits : 2012 Société Française d’Ichtyologie
http://archimer.ifremer.fr/doc/00092/20332/18611.pdf
http://archimer.ifremer.fr/doc/00092/20332/

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Chlordecone (Kepone) is an organochlorine insecticide that has been used as insecticide and fungicide. In the French West Indies, Guadeloupe and Martinique, it was intensively applied to banana fields from 1973 to 1993 to control root borers. This pesticide undergoes no significant biotic or abiotic degradation in the environment and is still present in soils where it was applied. It was only in 1999 that health and environmental authorities became aware of the extent of the chlordecone pollution of environmental media, including soils, waterways, and the food chain. Earlier observations and toxicological studies have demonstrated that chlordecone is a reproductive and developmental toxicant, neurotoxic and carcinogenic in rodents, and is an endocrine-disrupting chemical because of its estrogenic properties both in vitro and in vivo. Several surveys have confirmed that the French West Indian population continues to be exposed to this chemical though consumption of contaminated foodstuffs. Here, we report the findings of various epidemiological studies conducted in the French West Indies to assess the impact of environmental exposure to chlordecone on the health of the population.
ISSN: 0944-1344

hal-01150382
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01150382
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01150382/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01150382/file/Chlordecone%20exposure%20and%20adverse%20effects%20in%20French%20West.pdf
DOI : 10.1007/s11356-015-4621-5

Éditeur(s) : HAL CCSD
Résumé : International audience
The aim of this study was to examine the heart rate (HR) response to Olympic windsurfing competition and to check if there was any correlation between racing HR, performance, and the variables measured during laboratory maximal exercise. Ten elite windsurfers [age: 20.93 (3.46) years; height: 178.10 (6.34) cm; body mass: 66.79 (5.90) kg] performed a laboratory maximal oxygen consumption (VO2max) trial and national windsurf competitions wearing a HR monitor. One hundred and forty-three individual races were examined. Racing HR was expressed as a percentage of (1) HRmax (maximal treadmill HR) and (2) HRreserve (HRmax)HRrest). The performance (racing classification: RC, which is inversely proportional to performance) was significantly correlated to the racing HR response in both light wind (LW): LW)RC=)0.12(%HRreserve)+13.03; r=)0.71, r2=0.50, p<0.001, and medium wind (MW): MW)RC=)0.11(%HRreserve)+10.99; r=)0.66, r2=0.43, p<0.001. The results showed similar correlations between performance and %HRmax. Post racing lactate concentration was higher in LW compared to MW [7.14 (0.21) and 5.18 (2.02) mmolÆl)1, respectively]. There was a negative correlation between the highest racing HR (%HRreserve) of each athlete and the second ventilatory threshold expressed as a percentage of VO2max (r=-0.71, p<0.05). To summarize, this study showed that light and medium wind Olympic windsurfing performances are highly dependent on the capacity of the athlete to maintain a high HR for long periods of time. Furthermore, windsurfing is highly dependent on the athlete's physical fitness level as shown by the correlations between racing HRs and laboratory physiological variables.
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY

hal-00720564
https://hal.univ-antilles.fr/hal-00720564
https://hal.univ-antilles.fr/hal-00720564/document
https://hal.univ-antilles.fr/hal-00720564/file/Chamari_Wind_surf_and_Heart_rat.pdf

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Acquiring information is indisputably energy-consuming and conversely, the availability of information permits greater efficiency. Strangely, the scientific community long remained reluctant to establish a physical equivalence between the abstract notion of information and sensible thermodynamics. However, certain physicists such as Szilard and Brillouin proposed: (i) to give to information the status of a genuine thermodynamic entity (k B T ln2 joules/bit) and (ii) to link the capacity of storing information inferred from correlated systems, to that of indefinitely increasing organization. This positive feedback coupled to the self-templating molecular potential could provide a universal basis for the spontaneous rise of highly organized structures, typified by the emergence of life from a prebiotic chemical soup. Once established, this mechanism ensures the longevity and robustness of life envisioned as a general system, by allowing it to accumulate and optimize microstate-reducing recipes, thereby giving rise to strong nonlinearity, decisional capacity and multistability. Mechanisms possibly involved in priming this cycle are proposed.
ISSN: 0169-6149

inserm-00826658
http://www.hal.inserm.fr/inserm-00826658
http://www.hal.inserm.fr/inserm-00826658/document
http://www.hal.inserm.fr/inserm-00826658/file/OLEB-2013.pdf
DOI : 10.1007/s11084-013-9329-2