Éditeur(s) : Oxford Univ Press
Résumé : Spatio-seasonal explicit simulation models can predict the impact of spatial management measures on marine fish populations and fishing activities. As fisheries are complex systems, fisheries simulation models are often complex, with many uncertain parameters. Here, the methodology is provided to deliver fishery diagnostics within an uncertainty context using a complex simulation tool. A sensitivity analysis of the model is performed on model outputs using partial least-squares to identify the most sensitive parameters. The impact of several management measures is then simulated using a statistical simulation design taking into account the uncertainty of the selected sensitive parameters. This approach was applied to the Bay of Biscay anchovy stock using the ISIS-Fish (Integration of Spatial Information for Simulation of Fisheries) model to assess the impact of imposing marine protected areas (MPAs) conditionally on parameter uncertainty. The diagnostic appeared to be highly sensitive to the mortality of larvae and juveniles, growth, and reproduction. The uncertainty of the values of these parameters did not permit any of the simulated MPA designs to be proposed. However, according to anchovy catch and biomass, the simulations allowed the low impact of closure duration to be shown and underscored the utility of protecting such key processes as spawning.
Ices Journal Of Marine Science (1054-3139) (Oxford Univ Press), 2010-07 , Vol. 67 , N. 5 , P. 1063-1075

Droits : 2010 ICES/CIEM. Oxford journals
http://archimer.ifremer.fr/doc/00011/12234/9281.pdf
DOI:10.1093/icesjms/fsq002
http://archimer.ifremer.fr/doc/00011/12234/

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
It has been suggested that prenatal exposure to insecticides adversely affects fetal growth, but the overall results have been inconsistent, partly because of the different exposure sources and exposure assessments used. In the French PELAGIE (Perturbateurs Endocriniens: Étude Longitudinale sur les Anomalies de la Grossesse, l'Infertilité et l'Enfance) mother and child cohort (2002-2006), the authors investigated the association between fetal growth and insecticide exposure (n = 1,213) using an integrated Bayesian latent variable model to include multiple exposure sources: agricultural activities, nonorganic diet, household insecticide use on plants, and household insecticide use against insects. They used a questionnaire to collect information on household use and organic diet, and a national agricultural census provided data on agricultural activities in the women's municipalities of residence. A 0.10-cm decrease in head circumference at birth (95% credibility interval: -0.22, 0.01) was associated with fetal insecticide exposure from agricultural activities in the municipality of residence. Decreases in average birth weight (-27 g; 95% credibility interval: -59, 6) and head circumference (-0.12 cm; 95% credibility interval: -0.26, 0.01) were associated with household insecticide use to treat plants. The present results suggest an inverse association between fetal growth and prenatal insecticide exposure from nearby agricultural activity or household use. Bayesian modeling via latent variables is a natural framework for including multiple sources of exposure to environmental pollutants.
ISSN: 0002-9262

hal-00875979
https://hal.archives-ouvertes.fr/hal-00875979
DOI : 10.1093/aje/kwr422
PUBMED : 22534205

Éditeur(s) : Public Library Science
Résumé : The blue mussel, Mytilus edulis, is a commercially important species, with production based on both fisheries and aquaculture. Dynamic Energy Budget (DEB) models have been extensively applied to study its energetics but such applications require a deep understanding of its nutrition, from filtration to assimilation. Being filter feeders, mussels show multiple responses to temporal fluctuations in their food and environment, raising questions that can be investigated by modeling. To provide a better insight into mussel–environment interactions, an experiment was conducted in one of the main French growing zones (Utah Beach, Normandy). Mussel growth was monitored monthly for 18 months, with a large number of environmental descriptors measured in parallel. Food proxies such as chlorophyll a, particulate organic carbon and phytoplankton were also sampled, in addition to non-nutritious particles. High-frequency physical data recording (e.g., water temperature, immersion duration) completed the habitat description. Measures revealed an increase in dry flesh mass during the first year, followed by a high mass loss, which could not be completely explained by the DEB model using raw external signals. We propose two methods that reconstruct food from shell length and dry flesh mass variations. The former depends on the inversion of the growth equation while the latter is based on iterative simulations. Assemblages of food proxies are then related to reconstructed food input, with a special focus on plankton species. A characteristic contribution is attributed to these sources to estimate nutritional values for mussels. M. edulis shows no preference between most plankton life history traits. Selection is based on the size of the ingested particles, which is modified by the volume and social behavior of plankton species. This finding reveals the importance of diet diversity and both passive and active selections, and confirms the need to adjust DEB models to different populations and sites.
Plos One (1932-6203) (Public Library Science), 2014-10 , Vol. 9 , N. 10 , P. 1-13

Droits : 2014 Picoche 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/00218/32895/31380.pdf
http://archimer.ifremer.fr/doc/00218/32895/31381.pdf
http://archimer.ifremer.fr/doc/00218/32895/31382.pdf
http://archimer.ifremer.fr/doc/00218/32895/31383.pdf
http://archimer.ifremer.fr/doc/00218/32895/31384.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Orogenic wedges locally present chaotic tectonostratigraphic units that contain exotic blocks of various size, origin, age and lithology, embedded in a sedimentary matrix. The occurrence of ophiolitic blocks, sometimes huge, in such “mélanges” raises questions on (i) the mechanisms responsible for the incorporation of oceanic basement rocks into an accretionary wedge and (ii) the mechanisms allowing exhumation and redeposition of these exotic elements in “mélanges” during wedge growth.To address these questions, we present the results of a series of analogue experiments performed to characterize the processes and parameters responsible for accretion, exhumation and tectonosedimentary reworking of oceanic basement lithospheric fragments in an accretionary wedge.The experimental setup is designed to simulate the interaction between tectonics, erosion and sedimentation. Different configurations are applied to study the impact of various parameters, such as irregular oceanic floor due to structural inheritance, or the presence of layers with contrasted rheology that can affect deformation partitioning in the wedge (frontal accretion vs basal accretion) influencing its growth. Image correlation technique allows extracting instantaneous velocity field, and tracking of passive particles. By retrieving the particle paths determined from models, the pressure-temperature path of mélange units or elementary blocks can be discussed. The experimental results are then compared with observations from ophiolite-bearing mélanges in Taiwan (Lichi and Kenting mélanges) and Raman spectroscopy of carbonaceous material (RSCM) Thermometry data on rocks from the northern Apennines (Casanova mélange). A geological scenario is proposed following basic observations. The tectonic evolution of the retroside of doubly vergent accretionary wedges is mainly controlled by backthrusting and backfolding. The retro wedge is characterized by steep slopes that are prone to gravitational instabilities. It triggers submarine landslides inducing huge mass transfers. This erosion combined with backthrusting could favour exhumation of the ophiolitic fragments formerly accreted at the base of the wedge along the rough seafloor-sediments interface. Such an exhumed material can be reworked and deposited as debris- flows in proximal basins located at the foot of the retrowedge slope forming a tectono-sedimentary mélange. These syntectonic basins are continuously deformed and involved in prograding backthrusting-induced deformation.
ISSN: 0264-3707

hal-01395127
https://hal.archives-ouvertes.fr/hal-01395127
DOI : 10.1016/j.jog.2016.05.008

Éditeur(s) : HAL CCSD Elsevier
Résumé : Over-exploitation and fragmentation are serious problems for tropical forests. Most sustainable forest management practices avoid clear-cuts and apply selective logging systems focused on a few commercial species. We applied a simulation model to estimate the impact of such selective logging scenarios on the genetic diversity and demography of four tropical tree species from French Guiana. The simulations used data on genetic and demographic composition, growth, phenology and pollen and seed dispersal obtained for Dicorynia guianensis, Sextonia rubra, Symphonia globulifera and Vouacapoua americana at the experimental site in Paracou. Whereas Symphonia globulifera serves as a model for a species with low logging pressure, the other three species represent the most exploited tree species in French Guiana. In simulations with moderate logging, typical for French Guiana, with large cutting diameter (>60 cm diameter) and long cutting cycles (65 years), the two species V. americana and Sextonia rubra were not able to recover their initial stock at the end of the rotation period, with a large decrease in the number of individuals and in basal area. Under a more intensive logging system (cutting diameter >45 cm diameter, cutting cycles of 30 years) that is common practice in the Brazilian Amazon, only Symphonia globulifera showed no negative impact. Generally, the differences between the genetic parameters in the control scenarios without logging and the logging scenarios were surprisingly small. The main reasons for this were the overlapping of generations and the effective dispersal ability of gene vectors in all species, which guarantee relative homogeneity of the genetic structure in different age classes. Nevertheless, decreasing the population size by logging reduced the number of genotypes and caused higher genetic distances between the original population and the population at the end of the logging cycles. Sensitivity analysis showed that genetic changes in the logging scenarios were principally determined by the growth, densities and cutting diameter of each species, and only to a very small extent by the reproductive system including factors such as pollen and seed dispersal and flowering phenology
ISSN: 0006-3207

hal-01032050
https://hal.archives-ouvertes.fr/hal-01032050
DOI : 10.1016/j.biocon.2006.02.014

Éditeur(s) : HAL CCSD American Society for Biochemistry and Molecular Biology
Résumé : International audience
The budding yeast Saccharomyces cerevisiae is a major model organism for important biological processes such as mitotic growth and meiotic development, it can be a human pathogen, and it is widely used in the food-, and biotechnology industries. Consequently, the genomes of numerous strains have been sequenced and a very large amount of RNA profiling data is available. Moreover, it has recently become possible to quantitatively analyze the entire yeast proteome; however, efficient and cost-effective high-throughput protein profiling remains a challenge. We report here a new approach to direct and label-free large-scale yeast protein identification using a tandem buffer system for protein extraction, two-step protein prefractionation and enzymatic digestion, and detection of peptides by iterative mass spectrometry. Our profiling study of diploid cells undergoing rapid mitotic growth identified 86% of the known proteins and its output was found to be widely concordant with genome-wide mRNA concentrations and DNA variations between yeast strains. This paves the way for comprehensive and straightforward yeast proteome profiling across a wide variety of experimental conditions.
ISSN: 1535-9476

hal-00682837
https://hal.archives-ouvertes.fr/hal-00682837
DOI : 10.1074/mcp.M111.012682
PUBMED : 21997732

Résumé : Les forêts côtières inondables (FCI) des régions tropicales et subtropicales remplissent des fonctions écologiques nécessaires aux écosystèmes marins côtiers situés en aval et aux populations humaines vivant à proximité Aux Antilles, les mangroves et les forêts marécageuses à Pterocarpus officinalis sont structurés par des espèces ligneuses qui ont développé des adaptations particulières à la salinité, à l’inondation et aux substrats meubles sur lesquels elles reposent. Dans des contextes climatiques à forte saisonnalité, les saisons sèches prolongées entraînent de fortes variations de la salinité et du niveau de la nappe, que le changement climatique devrait amplifier. Les modèles climatiques de la région Caraïbe prévoient des saisons sèches plus sèches liées à une baisse des précipitations de 20 à 50 %. Or, la question des capacités de résistance et d’acclimatation des espèces ligneuses des FCI à des variations saisonnières marquées de leur environnement édaphique a été peu traitée dans la littérature scientifique.L’objectif de ce travail de thèse a été double. Il s’est agi, d'une part, de caractériser la structure et la croissance de faciès de végétation représentatifs des FCI antillaises et de mettre en évidence leurs déterminants. A cet effet, des individus adultes, des espèces ligneuses dominantes des FCI, (Avicennia germinans, Laguncularia racemosa, Pterocarpus officinalis, Rhizophora mangle), dans cinq faciès de végétation sur le gradient terre-mer, ont été suivis sur l'île de Grande-Terre (Guadeloupe). D’autre part, les effets de variations salines extrêmes sur la croissance et l’écophysiologie de ces quatre espèces ont été évalués au stade plantule par une expérience en conditions contrôlées.A travers cette étude, il a été montré que les différences de salinité et de fertilité entre les stationspermettent d’expliquer la composition et la structure des peuplements de FCI. Cette étude a égalementmontré que P. officinalis peut se maintenir dans une gamme de salinité plus large que ne l'indiquait lalittérature.Dans le contexte des Antilles où les marnages sont faibles, la saisonnalité du climat entraine des variations saisonnières importantes d’un ensemble de descripteurs édaphiques tels que le niveau de la nappe, la salinité du sol, le pH et le potentiel RedOx. L’inondation et la salinité des sols sont fortement corrélées aux variations mensuelles des précipitations. Les périodes sèches sont accompagnées de salinités élevées et d’une baisse du niveau de la nappe allant jusqu’à l’exondation des sols dans toutes les stations suivies. Les stress environnementaux liés à la saisonnalité entrainent une baisse de la production primaire. L’accroissement cambial mensuel des individus est fortement corrélé avec les précipitations et l’intensité du vent. Dans les stations de mangrove, la sècheresse édaphique régule la production primaire des palétuviers. En forêt marécageuse, la part de la sècheresse atmosphérique semble plus importante pour expliquer la production de P. officinalis. Aussi, les sècheresses édaphique et atmosphérique doivent être prises en compte toutes deux pour modéliser efficacement la croissance des peuplements des FCI.Lors de la saison sèche, le stress le plus important est le stress hydrique, lié à la diminution de la teneur en eau du sol et à l’augmentation de la salinité, qui entraine des contraintes physiologiques sur les palétuviers (ajustements stomatiques, pertes de surface foliaire et de conductivité hydraulique). Le stress ionique, lié à la toxicité des ions Na+ et Cl-, permet aussi d’expliquer une partie de la contrainte sur l’assimilation en carbone. En saison sèche, l’aération des sols ne se traduit pas par une amélioration des performances de croissance chez toutes les espèces. Aussi, la croissance cambiale maximale de toutes les espèces de FCI est réalisée en saison des pluies lorsque la salinité est faible et les niveaux d’inondation élevés.
In tropical and subtropical regions, flooded coastal forests provide essentials goods and services to local communities. In the Antilles, mangrove forests and the Pterocarpus officinalis swamp forest host tree species that are adapted to salinity, flooding and loose substrates. In areas were climatic seasonality is strong, dry seasons lead to strong fluctuations of soil salinity and water table level ; that climate change is likely to make stronger again. Climate model for the Caribbean project drier dry seasons with a decease of 20 to 50 % in annual rainfall amounts. However, resistance and acclimation ability of flooded coastal forest’s species to strong environmental fluctuations still remain poorly studied.This thesis aims two objectives. On the one hand, it aims to characterize the forest structure and monthly growth of vegetation structures representative of the Antillean flooded coastal forests and to highlight their determinants. In this respect, adult trees of the four dominant species of local flooded coastal forest (Avicennia germinans, Laguncularia racemosa, Pterocarpus officinalis, Rhizophora mangle), in five stations along a sea – land gradient were monitored on the Grande-Terre island (Guadeloupe). On the other hand, the effects of salinity variation patterns and salinity levels on growth performances and physiology of seedlings from the four same species were investigated through a greenhouse experiment.This study shows that differences among average salinity and soil fertility explain the vegetation structure of flooded coastal forest. It also extents, in the literature, the range of salinity in which P. officinalis can stand at the tree stage.In the Antilles were tidal range is small, climate seasonality lead to strong edaphic seasonal variations in water table level, soil salinity, pH and RedOx potential. Flooding and soil salinity are strongly correlated to monthly rainfall amounts: dry periods lead to high salinity and to a decrease in water table level under the soil surface. Seasonal environmental stresses lead to a decrease of primary production. Cambial growth was strongly correlated to monthly precipitation and average wind speed. In mangrove stations, edaphic drought determines primary production of mangrove trees, when, in swamp forest stations, atmospheric drought determines an important part of P. officinalis’ primary production.During the dry season, water stress is the more important environmental stress, both by the decrease in soil humidity and the increase in soil salinity, and leads to physiological strains (stomatal adjustment, loss of leaf area and hydraulic conductivity) for mangrove trees. Ionic toxicity of ions Na+ and Cl- also explains a part of the strain on carbon assimilation. During the dry season, re oxygenation of soils via low water table level does not lead to an increase of physiological traits. Thus, maximum cambial growth of all species is observed during the rainy season, when salinity is low and water table level is high.Flooded coastal forest’s species do not have the same ability to recover after a dry episode. In all the studied stations, A. germinans’ cambial growth rises back as soon as the rainy season starts, when, for one station, cambial growth of L. racemosa and R. mangle stay null during the three first month of the rainy season. This low ability to recover after a dry episode is correlated to a stronger impact of the dry season on the physiological traits of these two species.The greenhouse experiment shows that salinity variation patterns are to be taken into consideration for explaining seedlings’ growth and salinity tolerance. A stronger salinity increase impacts the growth of all the studied species; a punctual drop of salinity highlights that flooded coastal forest’s species differ in ability to take advantage of a low salinity episode. These results are coherent with field observations as cambial growth was fairly explained by monthly precipitation.

http://www.theses.fr/2013AGUY0674/document

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
During compressive events, deformation in sedimentary basins is mainly accommodated by thrust faulting and related fold growth. Thrust faults are generally rooted in the basement and may act as conduits or barriers for crustal fluid flow. Most of recent studies suggest that fluid flow through such discontinuities is not apparent and depends on the structural levels of the thrust within the fold-and-thrust belt. In order to constrain the paleofluid flow through the Jaca thrust-sheet-top basin (Paleogene southwest-Pyrenean fold-and-thrust belt) this study compares on different thrust faults located at different structural levels. The microstructures in the different fault zones studied are similar and consist of pervasive cleavage, calcite shear veins (SV1), extension veins (EV1) and late dilatation veins (EV3). In order to constrain the nature and the source of fluids involved in fluid-rock interactions within fault zones, a geochemical approach, based on oxygen and carbon stable isotope and trace element compositions of calcite from different vein generations and host rocks was adopted. The results suggest a high complexity in the paleohydrological behaviors of thrust faults providing evidence for a fluid-flow compartmentalization within the basin. Previous studies in the southern part of the Axial Zone (North of the Jaca basin) indicates a circulation of deep metamorphic water, probably derived from the Paleozoic basement, along fault zones related to the major basement Gavarnie thrust. In contrast, in northern part of the Jaca basin, the Monte Perdido thrust fault is affected by a closed hydrological fluid system involving formation water during its activity. The Jaca and Cotiella thrust faults, in turn, both located more to the south in the basin, are characterized by a composite fluid flow system. Indeed, stable isotope and trace element compositions of the first generations of calcite veins suggest a relatively closed paleohydrological system, whereas the late calcite vein generations, which are probably associated with the late tectonic activity of the basin, support a contribution of both meteoric and marine waters. Based on these results, a schematic fluid-flow model is presented. This model allows visualization of three main fluid flow compartments along a N-S transect.
ISSN: 0264-8172

hal-00963606
https://hal.archives-ouvertes.fr/hal-00963606
DOI : 10.1016/j.marpetgeo.2013.09.005

Éditeur(s) : HAL CCSD
Résumé : To study the dynamics of an orogen-foreland system and more particularly the impact of surface processes on its development, we base our work on two main axes. In a first part, using analogue tapered wedge models, we investigate the interplay between tectonics, erosion and sedimentation during the orogenic growth. The basis model mimics the evolution of a wedge section extending from the orogen to its foreland basin, with both the structural and the lithological heritages simulated. In a second part, the focus is on the recent tectonic and geomorphologic processes affecting the Swiss Prealpes klippen belt and surrounding structural units (Molasse basin and Jura fold-and-thrust belt). Remote sensing analyses allow to evaluate the impact of tectonics on the drainage pattern and landscape morphology. In addition, local field investigations in the Prealpes provide information on the nature and kinematic of brittle fractures and the paleostress fields.
Afin d'étudier la dynamique d'un système orogène/avant-pays et plus particulièrement l'impact des processus de surface sur son développement, notre travail se base sur deux axes principaux. Dans une première partie, à l'aide de modèles analogiques de prisme d'accrétion, nous analysons les interactions entre la tectonique, l'érosion et la sédimentation au cours de la croissance de l'orogène. Le modèle de base reproduit l'évolution d'une section de prisme, qui s'étend de l'orogène au bassin d'avant-pays, et où les héritages à la fois structural et lithologique sont simulés. Dans une seconde partie, l'accent est mis sur la tectonique récente et les processus géomorphologiques qui affectent la klippe des Préalpes suisses et les unités structurales environnantes (le bassin molassique et le Jura). Des analyses de télédétection permettent d'évaluer l'influence de la tectonique sur le réseau de drainage et la morphologie du paysage. De plus, des analyses de terrain menées localement dans les Préalpes fournissent des informations sur la nature et la cinématique des fractures cassantes et des champs de paléocontraintes.
https://tel.archives-ouvertes.fr/tel-00138836

tel-00138836
https://tel.archives-ouvertes.fr/tel-00138836
https://tel.archives-ouvertes.fr/tel-00138836/document
https://tel.archives-ouvertes.fr/tel-00138836/file/These_Bonnet_2007.pdf

Éditeur(s) : Société Française de Malacololgie
Résumé : Growth and proximate biochemical composition of the American oyster Crassostrea virginica were studied in the Patuxent river (Maryland), located in the middle reach of the Chesapeake bay (U.S.A.). The effects of stocking densities and environmental variables (depth, temperature) were examined in 1989-1990 on oyster population by using off-bottom culture. No significant density effect was observed on the shell growth, which is described by using a seasonally oscillating function. In contrast, the meat growth and the proximate biochemical composition were bath affected by the stacking density and the depth location. The variability of the resulting effects was observed based on a seasonal trend. Different hypothesis mainly related tO environmental conditions (food availability, current speed) are presented. Study implications on the oyster management in the Chesapeake bay are discussed.
La croissance et la composition biochimique de l'huître américaine Crassostrea virginica sont étudiés dans la rivière Patuxent, située dans la partie médiane de la baie de Chesapeake (U.S.A.). L'effet de la densité et de la profondeur d'élevage ainsi que de la température sont testés en 1989 et 1990 sur une population d'huîtres en élevage suspendu. La croissance de la coquille ne montre pas d'effet significatif de la densité d'élevage. Un modèle de la croissance en longueur avec oscillation saisonnière est établi. Les effets de la densité et de la profondeur sur l'évolution du poids de chair sèche et des composants biochimiques mettent en évidence une tendance saisonnière. Différentes hypothèses (quantité et qualité de la nourriture, effet de la vitesse du courant) sont présentées. Les implications de ces résultats sur l'aménagement de la baie de Chesapeake dans le cadre d'une réhabilitation de l'huître sont discutées.
Haliotis (Société Française de Malacololgie), 1994 , Vol. 23 , P. 113-123

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1994/publication-3076.pdf
http://archimer.ifremer.fr/doc/00000/3076/

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : In French Guiana, the population growth will result in an increase in demand for agricultural products and thus, will lead to an increase in the amount of tropical forests converted into cropland or pasture. Impacts of different agricultural systems on greenhouse gas (GHG) fluxes have not been studied in French Guiana. In this context, the fire-free chop-and-mulch method was used to convert a tropical forest site to agriculture. This study focused on soil nitrous oxide (N2O) emissions and we compared four land uses: (1) the undisturbed tropical forest, (2) recently converted grassland and recently converted croplands (fertilized soybean/maize rotation) with either (3) disk tillage or (4) no tillage.N2O measurements were obtained through the chamber technique and conducted over a 1-year period (measurements began 19 months after the forest was cleared). N2O fluxes were related to soil parameters measured at each sampling date: nitrate and ammonium contents, gravimetric water content (GWC) and temperature.Through the entire period, the mean (±standard error) and median N2O fluxes were 3.8 ± 0.5 and 2.7 g N ha−1 day−1, respectively for undisturbed tropical forest and 2.4 ± 0.9 and 0.8 g N ha−1 day−1, respectively for grassland (mowed Brachiaria ruziziensis). For croplands, no significant difference was found for N2O emissions between both agricultural practices. The mean (±standard error) and median N2O fluxes were 8.5 ± 1.2 and 4.0 g N ha−1 day−1, respectively for disk tillage plots and 8.5 ± 1.3 and 3.6 g N ha−1 day−1, respectively for no tillage plots. Nitrogen inputs (due to the application of fertilizer or due to the mineralization of crop residues) led to higher N2O fluxes, resulting in significantly higher mean N2O emissions from croplands compared to the forest, when only considering land use effect on N2O fluxes in a statistical model. The soil nitrate content, GWC and temperature had a significant positive effect on N2O fluxes. Taking into account these soil parameters in another statistical model, N2O emissions from croplands were not higher than the natural N2O emissions from tropical forest soils. Our results suggest that, if more forest will have to be converted in the course of the expected population growth in French Guiana, it could have low impact on the soil N2O fluxes (similar to natural fluxes from forest) with the improving of farming techniques (for example modification of the splitting of N-fertilizer) in the cropping plots.
ISSN: 0167-8809

hal-01204228
https://hal.archives-ouvertes.fr/hal-01204228
DOI : 10.1016/j.agee.2015.04.004
PRODINRA : 307607

Éditeur(s) : HAL CCSD Geological Society of America
Résumé : International audience
We combine surface structural measurements, subsurface seismic imaging, and magneto-stratigraphic dating to retrieve, through geometric modeling, the detailed history of fold growth and sedimentation across the Huerguosi anticline, on the northern Tianshan piedmont, taking advantage of a beautifully exposed section of growth strata. The model assumes a fault-bend folding mechanism, consistent with subsurface fold geometry. The shortening history is obtained by least-squares fitting of the measured dip angles of the growth strata. The shortening rate across the anticline is shown to have been remarkably constant: it increased only slightly from 0.84 ± 0.04 mm/yr between 10 and 4 Ma to 1.14 ± 0.02 mm/yr over the past 4 m.y. This approach also allows correcting syntectonic sedimentation rates for the effect of the fold growth and shows that the sedimentation rates in the piggyback basin increased abruptly from ~0.4 to ~0.7 mm/yr ca. 4 Ma.
ISSN: 0091-7613

insu-00338254
https://hal-insu.archives-ouvertes.fr/insu-00338254
DOI : 10.1130/G25073A.1

Éditeur(s) : HAL CCSD Springer-Verlag
Résumé : The Chile-Argentina Patagonian Cordillera is a natural laboratory to study the interactions between oceanic and continental lithosphere during the subduction of an active spreading ridge beneath a continent. Subduction of the South Chile spreading ridge, which separates the Nazca plate from the Antarctic plate, started around 15–14 Ma at the southern tip of Patagonia. Presently, the southernmost segment of the Chile Ridge enters the Peru-Chile trench at 46°S, at the site of the Chile Triple Junction (CTJ). We review the main events which occurred on land in the CTJ region (46–47°S), related with processes of ridge subduction. We summarize tectonic, sedimentary, and magmatic features in a 30 Ma-to Present chronological table. A preridge subduction stage, from 30 to 15 Ma, is characterized by the onset and growth of Patagonian relief and by a shift from marine to continental detrital sedimentation in the foreland at 20–22 Ma. The change from pre-ridge subduction to ridge subduction is marked on land by a transition from calc-alkaline to alkaline volcanism, at 14–12 Ma, and by the onset of eruption of very large fl ood basalt provinces (future volcanic plateaus) following rapid erosion of the eastern foreland belt. Post-plateau basaltic volcanism (<4 Ma) is coeval with a period of tectonic and morphological rejuvenation during which the eastern foreland of the Cordillera has been affected by extensional/transtensional tectonics. We place these events in the framework of a tectonomagmatic model involving the opening of slab windows due to both slab tear and ridge axis subduction.
Subduction Zone Geodynamics

hal-00421053
https://hal.archives-ouvertes.fr/hal-00421053
DOI : 10.1007/978-3-540-87974-9_12

Éditeur(s) : HAL CCSD
Résumé : Submitted to the Journal of Mathematical Analysis and Applications
International audience
We present new types of regularity for nonlinear generalized functions, based on the notion of regular growth with respect to the regularizing parameter of Colombeau's simplified model. This generalizes the notion of G^{ infty }-regularity introduced by M. Oberguggenberger. A key point is that these regularities can be characterized, for compactly supported generalized functions, by a property of their Fourier transform. This opens the door to microanalysis of singularities of generalized functions, with respect to these regularities. We present a complete study of this topic, including properties of the Fourier transform (exchange and regularity theorems) and relationship with classical theory, via suitable results of embeddings.
J. Math. Anal. Appl.

Droits : info:eu-repo/semantics/OpenAccess
hal-00020280
https://hal.archives-ouvertes.fr/hal-00020280
https://hal.archives-ouvertes.fr/hal-00020280/document
https://hal.archives-ouvertes.fr/hal-00020280/file/ADelcroixGRegularJan27.pdf
ARXIV : math/0603183

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
GenMol (TM) code is used to simulate Atomic Force Microscopy (AFM) tests at a kaolinite/brine/kaolinite contact, the confined fluid in sub-nanometre interspaces being in equilibrium with an external multi-species solution. The attraction/repulsion effort, i.e. the derivative versus the interspace aperture h of the interaction energy between both kaolinite faces, is computed versus the variable composition of the confined fluid (see for the method Part I of this work). Two external solutions are tested. Solution Si is a neutral brine (pH=7.5) leading to a possible attraction for apertures lower than 7 angstrom. Solution S2 is an acidified brine (pH=3.2) leading to repulsion whatever may be the aperture h. These two AFM simulations prove the existence of a critical pH value (3.2 < pH(crit) < 7.5) of the external solution, below which the acidification of a natural brine in a CO2 confinement inhibits adhesion between kaolinite aggregates.
ISSN: 0022-0248

hal-00544678
https://hal.archives-ouvertes.fr/hal-00544678
DOI : 10.1016/j.jcrysgro.2010.08.012

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Mechanical forces influence the growth and shape of virtually all tissues and organs. Recent studies show that increased cell contractibility, growth and differentiation might be normalized by modulating cell tensions. Particularly, the role of these tensions applied by the extracellular matrix during liver fibrosis could influence the hepatocarcinogenesis process. The objective of this study is to determine if 3D stiffness could influence growth and phenotype of normal and transformed hepatocytes and to integrate extracellular matrix (ECM) stiffness to tensional homeostasis. We have developed an appropriate 3D culture model: hepatic cells within three-dimensional collagen matrices with varying rigidity. Our results demonstrate that the rigidity influenced the cell phenotype and induced spheroid clusters development whereas in soft matrices, Huh7 transformed cells were less proliferative, well-spread and flattened. We confirmed that ERK1 played a predominant role over ERK2 in cisplatin-induced death, whereas ERK2 mainly controlled proliferation. As compared to 2D culture, 3D cultures are associated with epithelial markers expression. Interestingly, proliferation of normal hepatocytes was also induced in rigid gels. Furthermore, biotransformation activities are increased in 3D gels, where CYP1A2 enzyme can be highly induced/activated in primary culture of human hepatocytes embedded in the matrix. In conclusion, we demonstrated that increasing 3D rigidity could promote proliferation and spheroid developments of liver cells demonstrating that 3D collagen gels are an attractive tool for studying rigidity-dependent homeostasis of the liver cells embedded in the matrix and should be privileged for both chronic toxicological and pharmacological drug screening.
ISSN: 0730-2312

hal-01196600
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01196600
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01196600/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01196600/file/Increasing%203D%20Matrix%20Rigidity_accepted.pdf
DOI : 10.1002/jcb.25356

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
BACKGROUND: The TGF-β transforming growth factor is the most pleiotropic cytokine controlling a broad range of cellular responses that include proliferation, differentiation and apoptosis. The context-dependent multifunctional nature of TGF-β is associated with complex signaling pathways. Differential models describe the dynamics of the TGF-β canonical pathway, but modeling the non-canonical networks constitutes a major challenge. Here, we propose a qualitative approach to explore all TGF-β-dependent signaling pathways. RESULTS: Using a new formalism, CADBIOM, which is based on guarded transitions and includes temporal parameters, we have built the first discrete model of TGF-β signaling networks by automatically integrating the 137 human signaling maps from the Pathway Interaction Database into a single unified dynamic model. Temporal property-checking analyses of 15934 trajectories that regulate 145 TGF-β target genes reveal the association of specific pathways with distinct biological processes. We identify 31 different combinations of TGF-β with other extracellular stimuli involved in non-canonical TGF-β pathways that regulate specific gene networks. Extensive analysis of gene expression data further demonstrates that genes sharing CADBIOM trajectories tend to be co-regulated. CONCLUSIONS: As applied here to TGF-β signaling, CADBIOM allows, for the first time, a full integration of highly complex signaling pathways into dynamic models that permit to explore cell responses to complex microenvironment stimuli.
ISSN: 1752-0509

inserm-00978313
http://www.hal.inserm.fr/inserm-00978313
http://www.hal.inserm.fr/inserm-00978313/document
http://www.hal.inserm.fr/inserm-00978313/file/1752-0509-8-30.pdf
DOI : 10.1186/1752-0509-8-30

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
Large-scale periodic undulations within the oceanic and continental lithospheres revealed by a number of observations, are often treated as compressive instabilities, i.e. lithospheric buckling or folding. These undulations are normally associated with intensive faulting, which raises questions on the role of faulting in the folding process, and even on the possibility of folding in highly faulted media. In this study, we demonstrate that folding can "survive" faulting and that both processes may develop concurrently, so that faulting may serve as a mechanism of folding in the brittle domain. We support this hypothesis by direct numerical modeling. The results are compared with the data on three most prominent and well-known cases of the oceanic and continental folding-like deformation ("Indian Ocean" type, "Western Gobi (central Asia)" type and "Central Australian" type). We demonstrate that under reasonable tectonic stresses, folds can develop from faults cutting through the brittle parts of the lithosphere. The predicted wavelengths and nite growth rates are in agreement with the observations. We also show that within a continental lithosphere with thermotectonic age greater than 400 My, either a bi-harmonic mode (two superimposed wavelengths, crustal and mantle one) or a coupled mode (mono-layer deformation) of inelastic folding can develop, depending on the strength and thickness of the lower crust.
ISSN: 0094-8276

ird-00388016
http://hal.ird.fr/ird-00388016
http://hal.ird.fr/ird-00388016/document
http://hal.ird.fr/ird-00388016/file/fig3.pdf
http://hal.ird.fr/ird-00388016/file/fig1.pdf

Éditeur(s) : HAL CCSD
Résumé :   Diplôme : DEA
il s'agit d'un type de produit dont les métadonnées ne correspondent pas aux métadonnées attendues dans les autres types de produit : DISSERTATION
La lumière est le principal facteur limitant de la croissance en forêt tropicale humide. Malgré 1% du rayonnement incendie disponible en sous-bois, les jeunes arbres doivent rejoindre la canopée pour assurer la régénération du couvert. La compétition pour l'accès à la lumière est forte, et leur stabilité mécanique est souvent perturbée. La gravité étant un facteur omniprésent , tout déséquilibre entraîne des flexions de l'arbre et peut-être dramatique. Les arbres peuvent cependant palier ces déséquilibres en réorientant leurs axes par gravitropisme. Les "moteurs" des réorientations dans les axes lignifiés, sont la croissance radiale, la différentiation de bois de réaction et souvent, une croissance radiale excentrée.La capacité au redressement dépend aussi des dimensions des axes. Ces différents paramètres modulent donc la réponse gravitropique. Les réorientations dépendent de la croissance et donc également des ressources en lumière. Ce travail avait pour buts de quantifier l'impact de la croissance radiale sur le redressement d'une espèce tropicale et de mettre en évidence d'éventuelles différences d'efficience, de réorientation des arbres en fonction de la disponibilité en lumière. La réponse gravitropique de jeunes Symphonia globulifera artificiellement inclinés a été étudiée sous deux niveaux de lumière (1% et 25%°). L'importance de la croissance radiale dans la réaction gravitropique a été quantifiée par une analyse cinématique du redressement et l'utilisation d'un modèle biomécanique simple. Ce travail montre que même à 1% de lumière, les arbres ont une réponse gravitropique. L'efficience de réaction est d'ailleurs plus forte qu'à 25% de lumière. Cette réaction semble donc être une fonction prédominante pour les plantes en sous-bois. Nous avons également montré que le redressement est fortement corrélé à la vitesse de croissance radiale. Les données obtenues complètent celles déjà acquises sur des espèces tempérées. Elles permettront des comparaisons interspécifiques du processus gravitropique et serviront à valider des modèles biomécaniques plus complexes que celui utilisé dans cette étude.
https://hal.archives-ouvertes.fr/hal-01189227

hal-01189227
https://hal.archives-ouvertes.fr/hal-01189227
PRODINRA : 16967

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The modern high topography of the Tianshan resulted from the reactivation of a Paleozoic orogenic belt by the India/Asia collision. Today, the range exhibits tectonically active forelands and intermontane basins. Based on quantitative morphotectonic observations and age constraints derived from cosmogenic 10Be dating, single-grain post-infrared infrared stimulated luminescence (p-IR IRSL) dating and modeling of fault scarp degradation, we quantify the deformation in the Nalati and Bayanbulak intermontane basins in the central Eastern Tianshan. Our results indicate that at least 1.4 mm/yr of horizontal crustal shortening is accommodated within these two basins. This shortening represents over 15% of the 8.5 ± 0.5 mm/yr total shortening rate across the entire range at this longitude. This shortening rate implies that the Eastern Central Tianshan is thickening at a mean rate of ∼1.4 mm/yr, a rate that is significantly higher than the average denudation rate of 0.14 mm/yr derived from our cosmogenic analysis. This discrepancy suggests that the Tianshan range has not yet reached a steady-state topography and remains in a transient state of topographic growth, most likely due to limited denudation rates driven by the arid climate of Central Asia.
ISSN: 0012-821X

insu-01610154
https://hal-insu.archives-ouvertes.fr/insu-01610154
DOI : 10.1016/j.epsl.2017.09.025