Éditeur(s) : Université des Antilles Études caribéennes
Résumé : L’Asie insulaire, forte exportatrice de main-d’œuvre féminine possède-t-elle un système migratoire propre ? Les cas indonésien, philippin et sri-lankais.Les migrations de travail ont une longue tradition en Asie. Instaurées par les puissances coloniales européennes par le biais des contrats de travail, après l’abolition de l’esclavage, elles ont ainsi favorisé l’expansion de deux solides diasporas, l’une chinoise, l’autre indienne.Ce vaste continent qui abrite désormais 60 % de la population mondiale et les deux tiers de la force de travail mondiale demeure, pour longtemps encore, une zone de très forte mobilité.Trois pays, dont deux archipels et une île, les Philippines, l’Indonésie et le Sri Lanka, sont devenus, en l’espace d’une à trois décennies, les principaux exportateurs de main-d’œuvre à l’échelle mondiale. Ces politiques migratoires visent d’une part à réduire la pauvreté et le chômage et d’autre part à accroître les indispensables rentrées de devises par le biais des transferts financiers des migrants. La féminisation des flux migratoires est particulièrement marquée en Asie insulaire où la proportion de femmes avoisine les 70 % du total des migrants.
The labour migration have a long tradition in Asia. Migration, which were introduced by European colonial powers (through employment contracts, after the abolition of slavery), have encouraged the expansion of two solid diasporas, 'One China, one Indian. This vast continent, home now 60% of the world's population and two thirds of the global labor force, remains for a long time, a zone of very high mobility. Three countries, including two archipelagos and one island, the Philippines, Indonesia and Sri Lanka are now in the space of one to three decades, the main exporters of labour globally. The objective of these policies migration is a part of reducing poverty and unemployment, and secondly to increase the necessary cash currency, with financial transfers of migrants. The feminization of migration is particularly marked in Asia island where the proportion of women is around 70% of total migrants
Indonésie
Philippines
Sri Lanka

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.982
http://journals.openedition.org/etudescaribeennes/982

Éditeur(s) : CRILLASH : Centre de Recherches Interdisciplinaires en Lettres, Langues, Arts et Sciences Humaines Association YES YOU CAN Formations
Extrait de : "La variation linguistique" : journée d'étude, le 27 avril 2018. Université des Antilles
Description : Corinne Mencé-Caster, Professeure à l'Université Paris Sorbonne - Paris IV, établit des liens entre linguistique et différentes idéologies (politiques, sociales...) pour démontrer que la question de la variation linguistique peut constituer un élément perturbateur. Pour parvenir à ses fins, elle part du principe que tout locuteur d'une langue tend toujours à croire que cette langue a un caractère statique. Néanmoins, il est souvent amené à constater l'évolution de cette langue et les variations qui l'encadrent. Ce constat est rendu possible de nos jours par le biais des réseaux sociaux. C'est en ce sens que l'intervenante s'oppose à la position exprimée naguère par Ferdinand de Saussure, vu que pour celui-ci toute approche scientifique de la langue ne peut se faire en-dehors du double paradigme du statisme et de l'homogénéité.

Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V18147
V18147

Éditeur(s) : EDP Sciences
Résumé : Twelve diel surveys were carried out in three reservoirs of Sri Lanka viz. Minneriya, Udawalawe and Victoria, to investigate diel feeding patterns, daily ration and relative food consumption in fish populations. Stomach content weights of different size classes of various fish species in the three reservoirs in 12 diel surveys were analysed using an iterative method, MAXIMS. Predominantly herbivorous or detritivorous fish species such as Amblypharyngodon melettinus and Oreochromis niloticus exhibited one peak in the diel feeding pattern. Two peak feeding periods were evident in predominantly insectivores and/or zooplanktivores (e. g., Puntius chola and Rasbora daniconius) and interestingly in macrophyte feeders (i.e., Etroplus suratensis, Puntius filamentosus and Tilapia rendalli). It might be possible that all species with two feeding peaks in diel feeding patterns rely on vision for feeding. Food consumption per biomass (Q/B ratio) defined as amount of food consumed per unit weight of an age-structured population of fish was estimated on the basis of the average quantities of food consumed over a long period of time by various size classes in order to minimize the bias of estimates.
Douze séries d'échantillonnage ont été effectuées dans trois lacs-réservoirs du Sri Lanka : Minneriya, Udawalawe et Victoria, afin d'étudier le modèle journalier d'alimentation, les rations journalières et à la consommation relative des populations de poissons. Les poids des contenus stomacaux de différentes classes de taille ont ainsi été analysés en utilisant une méthode itérative, MAXIMS. Les espèces herbivores ou détritivores telles que Amblypharyngodon melettinus et Oreochromis niloticus montrent un pic dans l'activité de nutrition. Tandis que les espèces détrivores et/ou zooplanctivores en présentent deux (ex., Puntius chola et Rasbora daniconius) de même que des espèces se nourrissant de macrophytes (ex., Etroplus suratensis, Puntius filamentosus et Tilapia rendalli). Il est possible que la vision joue un rôle chez ces espèces présentant deux pics journaliers d'alimentation. La consommation de nourriture par rapport à la biomasse (le rapport Q/B) est défini comme la quantité d'aliment consommé par unité de poids d'une population de poissons structurée en âge, sur la base de quantités moyennes de nourriture consommée sur une longue période de temps et par diverses classes de taille, afin de minimiser les biais dans les estimations.
Aquatic Living Resources (0990-7440) (EDP Sciences), 2006-07 , Vol. 19 , N. 3 , P. 229-237

Droits : 2006 EDP
http://archimer.ifremer.fr/doc/2006/publication-2134.pdf
DOI:10.1051/alr:2006023
http://archimer.ifremer.fr/doc/00000/2134/

Éditeur(s) : Université des Antilles Louisiana State University CRILLASH : Centre de Recherches Interdisciplinaires en Lettres, Langues, Arts et Sciences Humaines Institut du Tout-Monde
Extrait de : "Edouard Glissant, l'éclat et l'obscur" : colloque international, du 19 au 23 mars 2018. Université des Antilles
Description : Mylène DANGLADES, Professeure à l'Université de la Guyane, s'attardera sur les écrits du Tout-Monde pour faire son exposé. Elle indique que le Tout-Monde est une parole ouverte qui s'offre au monde. C'est par le biais de l'écriture ou de la langue qu'on peut percevoir le mystère du vivant ou de s'en approcher. L'oeuvre glissantienne en témoigne.

Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V18084
V18084

Éditeur(s) : HAL CCSD Annual Reviews
Résumé : International audience
The record of the continental lithosphere is patchy and incomplete; no known rock is older than 4.02 Ga, and less than 5% of the rocks preserved are older than 3 Ga. In addition, there is no recognizable mantle lithosphere from before 3 Ga. We infer that there was lithosphere before 3 Ga and that ∼3 Ga marks the stabilization of blocks of continental lithosphere that have since survived. This was linked to plate tectonics emerging as the dominant tectonic regime in response to thermal cooling, the development of a more rigid lithosphere, and the recycling of water, which may in turn have facilitated plate tectonics. A number of models, using different approaches, suggest that at 3 Ga the volume of continental crust was ∼70% of its present-day volume and that this may be a minimum value. The continental crust before 3 Ga was on average more mafic than that generated subsequently, and this pre-3 Ga mafic new crust had fractionated Lu/Hf and Sm/Nd ratios as inferred for the sources of tonalite-trondhjemite-granodiorite and later granites. The more intermediate composition of new crust generated since 3 Ga is indicated by its higher Rb/Sr ratios. This change in composition was associated with an increase in crustal thickness, which resulted in more emergent crust available for weathering and erosion. This in turn led to an increase in the Sr isotope ratios of seawater and in the drawdown of CO2. Since 3 Ga, the preserved record of the continental crust is marked by global cycles of peaks and troughs of U-Pb crystallization ages, with the peaks of ages appearing to match periods of supercontinent assembly. There is increasing evidence that the peaks of ages represent enhanced preservation of magmatic rocks in periods leading up to and including continental collision in the assembly of supercontinents. These are times of increased crustal growth because more of the crust that is generated is retained within the crust. The rates of generation of continental crust and mantle lithosphere may have remained relatively constant at least since 3 Ga, yet the rates of destruction of continental crust have changed with time. Only relatively small volumes of rock are preserved from before 3 Ga, and so it remains difficult to establish which of these are representative of global processes and the extent to which the rock record before 3 Ga is distorted by particular biases.
ISSN: 0084-6597

hal-01622692
https://hal.archives-ouvertes.fr/hal-01622692
DOI : 10.1146/annurev-earth-063016-020525

Éditeur(s) : Université des Antilles AIHP-GEODE : Archéologie Industrielle, Histoire, Patrimoine/Géographie- Développement Environnement de la Caraïbe HARCMAR : Histoire et Archéologie Maritimes des Petites Antilles
Extrait de : "Entre exclusif et contrebande, le commerce colonial aux Antilles XVIIe-début XIXe siècle" : journées d'étude, du 24 au 26 octobre 2019. Université des Antilles
Description : « Tempora mutantur et Nos mutamur in illis », (Les temps changent et nous changeons avec eux). Cette citation tirée d'une lettre écrite en 1664 par Adam Erckelens, chirurgien du Sieur Nicolaas Claesz, planteur à Capesterre de Guadeloupe, résume bien l'attitude et la force des Hollandais de cette époque. Elle illustre également la situation incertaine dans laquelle ils se trouvaient à la fin de l'année 1664. En effet, 1664 - 1665, fut une période délicate pour le commerce néerlandais dans les Antilles. A partir de lettres de marchands, planteurs et commissionnaires hollandais saisies par les navires anglais, se dessinent les relations commerciales exclusives légales ou illégales des différents ports de Pays-Bas avec la zone caraïbe et notamment les Antilles françaises ; type de marchandises échangées, traite des Noirs, méthodes commerciales. Ces lettres mettent en lumière les protagonistes aussi bien en Europe que sur place. Tout ceci dans une situation politique en évolution par la volonté des autorités françaises et notamment de Colbert désireux d'éliminer les Hollandais du commerce antillais par le biais de la création de la Compagnie des Indes Occidentales. L'incertitude sur l'avenir est également due à la tension entre Pays-Bas et l'Angleterre qui aboutira à la Seconde guerre anglo-hollandaise (1665 - 1667).
Siècle(s) traité(s) : 17
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V19115
V19115

Éditeur(s) : HAL CCSD Geological Society of America
Résumé : International audience
Because of its essential role in coupling climate and tectonics, denudation is a key parameter when constraining the history of Earth’s surface. This is particularly true at the Pliocene-Pleistocene transition, and the potential impact of the onset of Quaternary glaciations remains strongly debated. In the present study, we measured in situ cosmogenic 10Be within continuous late Cenozoic sedimentary sections that had already been dated using magnetostratigraphy. The new data were obtained from four sedimentary basins in the northern and southern Tianshan range (Central Asia). We first thoroughly discuss how in situ cosmogenic 10Be concentrations can be corrected for radioactive decay and for the contribution of postdepositional cosmogenic accumulation to derive the paleo–denudation rates. Our analysis shows that, in the four sedimentary records, the potential bias remains low enough to consider the derived denudation rates reliable. The four records, although likely influenced by local particularities due to lithological heterogeneity and local tectonics, display similar trends of continuously increasing denudation between ca. 9 Ma and the present. These rates have remained relatively high but steady since 4 Ma, ∼1.5 m.y. before the onset of the Quaternary glacial cycles. Though the rejuvenation of the Tianshan range since 11 Ma may explain most of the progressive increase (×5) in denudation, our data suggest that the Quaternary glaciations had only a limited impact on denudation in the Tianshan. Our data, however, indicate an increase in the spatial and high-frequency variability (<1 m.y.) of the denudation rates between 3 and 1 Ma. This may correspond to a transient readjustment of the landscape in response to the onset of Quaternary glacial cycles.
ISSN: 0016-7606

hal-01685766
https://hal.archives-ouvertes.fr/hal-01685766
DOI : 10.1130/B31475.1

Éditeur(s) : Elsevier
Résumé : To better understand the recent motion of the Pacific plate relative to the Rivera plate and to better define the limitations of the existing Rivera-Pacific plate motion models for accurately predicting this motion, total-field magnetic data, multibeam bathymetric data and sidescan sonar images were collected during the BART and FAMEX campaigns of the N/O L'Atalante conducted in April and May 2002 in the area surrounding the Moctezuma Spreading Segment of the East Pacific Rise, located offshore of Manzanillo, Mexico, at 106 degrees 16'W, between 17.8 degrees N and 18.5 degrees N. Among the main results are: (1) the principle transform displacement zone of the Rivera Transform is narrow and well defined east of 107 degrees 15'W and these azimuths should be used preferentially when deriving new plate motion models, and (2) spreading rates along the Moctezuma Spreading Segment should not be used in plate motion studies as either seafloor spreading has been accommodated at more than one location since the initiation of seafloor spreading in the area of the Moctezuma Spreading Segment, or this spreading center is not a Rivera-Pacific plate boundary as has been previously assumed. Comparison of observed transform azimuths with those predicted by the best-fit poles of six previous models of Rivera-Pacific relative motion indicate that, in the study area, a significant systematic bias is present in the predictions of Rivera-Pacific motion. Although the exact source of this bias remains unclear, this bias indicates the need to derive a new Rivera-Pacific relative plate motion model.
Tectonophysics (0040-1951) (Elsevier), 2008-06 , Vol. 454 , N. 1-4 , P. 70-85

Droits : 2008 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2008/publication-4486.pdf
DOI:10.1016/j.tecto.2008.04.013
http://archimer.ifremer.fr/doc/00000/4486/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Sedimentary rocks and detrital minerals sample large areas of the continental crust, and they are increasingly seen as a reliable archive for its global evolution. This study presents two approaches to model the growth of the continental crust through the sedimentary archive. The first builds on the variations in U-Pb, Hf and O isotopes in global databases of detrital zircons. We show that uncertainty in the Hf isotope composition of the mantle reservoir from which new crust separated, in the 176Lu/177Hf ratio of that new crust, and in the contribution in the databases of zircons that experienced ancient Pb loss(es), adds some uncertainty to the individual Hf model ages, but not to the overall shape of the calculated continental growth curves. The second approach is based on the variation of Nd isotopes in 645 worldwide fine-grained continental sedimentary rocks with different deposition ages, which requires a correction of the bias induced by preferential erosion of younger rocks through an erosion parameter referred to as K. This dimensionless parameter relates the proportions of younger to older source rocks in the sediment, to the proportions of younger to older source rocks present in the crust from which the sediment was derived. We suggest that a Hadean/Archaean value of K = 1 (i.e., no preferential erosion), and that post-Archaean values of K = 4–6, may be reasonable for the global Earth system. Models built on the detrital zircon and the fine-grained sediment records independently suggest that at least 65% of the present volume of continental crust was established by 3 Ga. The continental crust has been generated continuously, but with a marked decrease in the growth rate at ~ 3 Ga. The period from > 4 Ga to ~ 3 Ga is characterised by relatively high net rates of continental growth (2.9–3.4 km3 yr− 1 on average), which are similar to the rates at which new crust is generated (and destroyed) at the present time. Net growth rates are much lower since 3 Ga (0.6–0.9 km3 yr− 1 on average), which can be attributed to higher rates of destruction of continental crust. The change in slope in the continental growth curve at ~ 3 Ga is taken to indicate a global change in the way bulk crust was generated and preserved, and this change has been linked to the onset of subduction-driven plate tectonics. At least 100% of the present volume of the continental crust has been destroyed and recycled back into the mantle since ~ 3 Ga, and this time marks a transition in the average composition of new continental crust. Continental crust generated before 3 Ga was on average mafic, dense, relatively thin (< 20 km) and therefore different from the calc-alkaline andesitic crust that dominates the continental record today. Continental crust that formed after 3 Ga gradually became more intermediate in composition, buoyant and thicker. The increase in crustal thickness is accompanied by increasing rates of crustal reworking and increasing input of sediment to the ocean. These changes may have been accommodated by a change in lithospheric strength at around 3 Ga, as it became strong enough to support high-relief crust. This time period therefore indicates when significant volumes of continental crust started to become emergent and were available for erosion and weathering, thus impacting on the composition of the atmosphere and the oceans.
ISSN: 0037-0738

hal-01622696
https://hal.archives-ouvertes.fr/hal-01622696
DOI : 10.1016/j.sedgeo.2017.06.001

Éditeur(s) : HAL CCSD Ecological Society of America
Résumé : Line transect surveys are widely used in neotropical rainforests to estimate the population abundance of medium- and large-sized vertebrates. The use of indices such as Encounter Rate has been criticized because the probability of animal detection may fluctuate due to the heterogeneity of environmental conditions among sites. In addition, the morphological and behavioral characteristics (biological traits) of species affect their detectability. In this study, we compared the extent to which environmental conditions and species' biological traits bias abundance estimates in terra firme rainforests in French Guiana. The selected environmental conditions included both physical conditions and forest structure covariates, while the selected biological traits included the morphological and behavioral characteristics of species. We used the distance sampling method to model the detection probability as an explicit function of environmental conditions and biological traits and implemented a model selection process to determine the relative importance of each group of covariates. Biological traits contributed to the variability of animal detectability more than environmental conditions, which had only a marginal effect. Detectability was best for large animals with uniform or disruptive markings that live in groups in the canopy top. Detectability was worst for small, solitary, terrestrial animals with mottled markings. In the terra firme rainforests which represent ~80% of the Amazonia and Guianas regions, our findings support the use of relative indices such as the encounter rate to compare population abundance between sites in species-specific studies. Even though terra firme rainforests may appear similar between regions of Amazonia and the Guianas, comparability must be ensured, especially in forests disturbed by human activity. The detection probability can be used as an indicator of species' vulnerability to hunting and, thus, to the risk of local extinction. Only a few biological trait covariates are required to correctly estimate the detectability of the majority of medium- and large-sized vertebrates. Thus, a biological trait model could be useful in predicting the detection probabilities of rare, uncommon or localized species for which few data are available to fit the detection function.
ISSN: 1051-0761

hal-01555267
https://hal.archives-ouvertes.fr/hal-01555267
DOI : 10.1002/eap.1549
PRODINRA : 396614
PUBMED : 28419598

Éditeur(s) : HAL CCSD
Résumé : We unify the definitions of phylogenetic and functional entropy and diversity as a generalization of HCDT entropy when an ultrametric tree is considered. We derive the decomposition of phylodiversity and its estimation bias correction to allow its estimation from real, often undersampled data. Phyloentropy can be transformed into phylodiversity to provide a measure of true diversity, i.e. an effective number of species or communities.
https://hal-agroparistech.archives-ouvertes.fr/hal-00946177

hal-00946177
https://hal-agroparistech.archives-ouvertes.fr/hal-00946177
https://hal-agroparistech.archives-ouvertes.fr/hal-00946177/document
https://hal-agroparistech.archives-ouvertes.fr/hal-00946177/file/HAL_Decomposing_Phylodiversity.pdf

Éditeur(s) : HAL CCSD MDPI
Résumé : International audience
Satellite precipitation products are a means of estimating rainfall, particularly in areas that are sparsely equipped with rain gauges. The Guiana Shield is a region vulnerable to high water episodes. Flood risk is enhanced by the concentration of population living along the main rivers. A good understanding of the regional hydro-climatic regime, as well as an accurate estimation of precipitation is therefore of great importance. Unfortunately, there are very few rain gauges available in the region. The objective of the study is then to compare satellite rainfall estimation products in order to complement the information available in situ and to perform a regional analysis of four operational precipitation estimates, by partitioning the whole area under study into a homogeneous hydro-climatic region. In this study, four satellite products have been tested, TRMM TMPA (Tropical Rainfall Measuring Mission Multisatellite Precipitation Analysis) V7 (Version 7) and RT (real time), CMORPH (Climate Prediction Center (CPC) MORPHing technique) and PERSIANN (Precipitation Estimation from Remotely-Sensed Information using Artificial Neural Network), for daily rain gauge data. Product performance is evaluated at daily and monthly scales based on various intensities and hydro-climatic regimes from 1 January 2001 to 30 December 2012 and using quantitative statistical criteria (coefficient correlation, bias, relative bias and root mean square error) and quantitative error metrics (probability of detection for rainy days and for no-rain days and the false alarm ratio). Over the entire study period, all products underestimate precipitation. The results obtained in terms of the hydro-climate show that for areas with intense convective precipitation, TMPA V7 shows a better performance than other products, especially in the estimation of extreme precipitation events. In regions along the Amazon, the use of PERSIANN is better. Finally, in the driest areas, TMPA V7 and PERSIANN show the same performance.
ISSN: 2072-4292

Droits : http://hal.archives-ouvertes.fr/licences/copyright/
hal-01257912
https://hal.archives-ouvertes.fr/hal-01257912
https://hal.archives-ouvertes.fr/hal-01257912/document
https://hal.archives-ouvertes.fr/hal-01257912/file/remotesensing-07-15831.pdf
DOI : 10.3390/rs71215831

Éditeur(s) : Elsevier
Résumé : Genetic variation was surveyed at 11 microsatellite loci and at 517 bp of the mitochondrial control region to investigate the presence of genetic stock structure in swordfish (Xiphias gladius) in four proximal localities of the southwest Indian Ocean. One aim of this study was to serve as a preliminary examination for congruency of structure detected by these two genetic markers, prior to conducting a more comprehensive basin-wide survey of the Indian Ocean and nearby surrounding areas. Analyses of multilocus microsatellite genotypes and mitochondrial control region sequences both revealed a great homogeneity between samples. Genetic diversity detected at the regional scale was not significantly higher than detected at the local scale. Results suggest that the southwest Indian Ocean globally functions as a unique panmictic population. However, some discrete genetic differences appeared that could possibly indicate influence from a second genetic pool in the northern part of the Indian Ocean. This structure appeared to be sex-dependent with genetic differences higher among female than among male samples. This result may indicate a higher level of spawning area fidelity for females with a subsequent sampling bias tending to homogenise male genotypic distributions. (c) 2009 Elsevier B.V. All rights reserved.
Fisheries Research (0165-7836) (Elsevier), 2009-05 , Vol. 97 , N. 3 , P. 263-269

Droits : 2009 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2009/publication-6455.pdf
DOI:10.1016/j.fishres.2009.03.004
http://archimer.ifremer.fr/doc/00000/6455/

Éditeur(s) : Taylor & Francis Ltd
Résumé : A new method is developed to estimate daily turbulent airsea fluxes over the global ocean on a 0.25 degrees grid. The required surface wind speed (w(10)) and specific air humidity (q(10)) at 10m height are both estimated from remotely sensed measurements. w(10) is obtained from the SeaWinds scatterometer on board the QuikSCAT satellite. A new empirical model relating brightness temperatures (T-b) from the Special Sensor Microwave Imager (SSM/I) and q(10) is developed. It is an extension of the author's previous q(10) model. In addition to T-b, the empirical model includes sea surface temperature (SST) and airsea temperature difference data. The calibration of the new empirical q(10) model utilizes q(10) from the latest version of the National Oceanography Centre airsea interaction gridded data set (NOCS2.0). Compared with mooring data, the new satellite q(10) exhibits better statistical results than previous estimates. For instance, the bias, the root mean square (RMS), and the correlation coefficient values estimated from comparisons between satellite and moorings in the northeast Atlantic and the Mediterranean Sea are 0.04gkg(1), 0.87gkg(1), and 0.95, respectively. The new satellite q(10) is used in combination with the newly reprocessed QuikSCAT V3, the latest version of SST analyses provided by the National Climatic Data Center (NCDC), and 10m air temperature estimated from the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalyses (ERA-Interim), to determine three daily gridded turbulent quantities at 0.25 degrees spatial resolution: surface wind stress, latent heat flux (LHF), and sensible heat flux (SHF). Validation of the resulting fields is performed through a comprehensive comparison with daily, in situ values of LHF and SHF from buoys. In the northeast Atlantic basin, the satellite-derived daily LHF has bias, RMS, and correlation of 5Wm(2), 27Wm(2), and 0.89, respectively. For SHF, the statistical parameters are 2Wm(2), 10Wm(2), and 0.94, respectively. At global scale, the new satellite LHF and SHF are compared to NOCS2.0 daily estimates. Both daily fluxes exhibit similar spatial and seasonal variability. The main departures are found at latitudes south of 40 degrees S, where satellite latent and sensible heat fluxes are generally larger.
International Journal Of Remote Sensing (0143-1161) (Taylor & Francis Ltd), 2013-07 , Vol. 34 , N. 14 , P. 5243-5261

Droits : 2013 Taylor & Francis
http://archimer.ifremer.fr/doc/00137/24825/23575.pdf
DOI:10.1080/01431161.2013.787502
http://archimer.ifremer.fr/doc/00137/24825/

Éditeur(s) : HAL CCSD University of California, Los Angeles
Résumé : International audience
entropart is a package for R designed to estimate diversity based on HCDT entropy or similarity-based entropy. It allows calculating species-neutral, phylogenetic and functional entropy and diversity, partitioning them and correcting them for estimation bias. © 2015, American Statistical Association.
ISSN: 1548-7660

hal-01502646
https://hal-agroparistech.archives-ouvertes.fr/hal-01502646
DOI : 10.18637/jss.v067.i08

Résumé : En 1999, le risque écologique encouru par les écosystèmes côtiers soumis à la prolifération de la crépidule, Crepidula fornicata, a été pleinement reconnu par la communauté scientifique nationale et internationale. Au niveau national, le Programme National Environnement Côtier (PNEC) et le programme national LITEAU ont tous deux identifié des actions thématiques prioritaires sur la dynamique de prolifération de la crépidule et les interactions crépidule/bivalves exploités. Les actions du LEMAR (UMR 6539 CNRS) sur cette thématique s’inscrivent dans deux projets : 1 - La crépidule : identifier les mécanismes de sa prolifération et caractériser ses effets sur le milieu pour envisager sa gestion. » (LITEAU) 2 - Recrutement, milieu physique et interactions d'espèces en environnement côtier : cas des mollusques » (PNEC ART2) En rade de Brest, l’accent est mis sur l’interaction des cycles biologiques de la crépidule et de la coquille Saint-Jacques. Les objectifs poursuivis en rade de Brest s’articulent en 4 points, dans le cadre de LITEAU : 1- Dynamique de colonisation de la crépidule en rade de Brest : acquisition des paramètres de dynamique de population (caractéristiques du cycle reproducteur, déterminisme du recrutement, dispersion, croissance, sensibilité aux efflorescences toxiques...) ; 2- Impact de cette prolifération sur l’évolution de la nature sédimentaire des zones colonisées et l’enrichissement en matière organique (par le biais de l’activité alimentaire et de la production de biodépôts) ; 3- Modifications engendrées sur les peuplements benthiques dans leur globalité (sites ateliers). La strate à crépidules, au sens biosédimentaire et écologique, verra sa définition affinée et sa dynamique analysée en vue d'obtenir un modèle prévisionnel des évolutions possibles en matière de biodiversité ; 4- Rôle de la crépidule dans le contrôle de la production primaire phytoplanctonique (par le biais des activités de filtration et de production de biodépôts).

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00032/14292/11570.pdf
http://archimer.ifremer.fr/doc/00032/14292/

Éditeur(s) : HAL CCSD
Résumé : Understanding of the mechanisms driving diversification of species is a significant way to improve the management of ecosystems, predict the impacts of climate change and understand the actual and past biodiversity level. The aim of this thesis is to understand and comprehend genetic mechanisms behind the diversification of species in the presence of gene flow. This thesis is focused on the biological model Symphonia globulifera, which presents two ecotypes: the S.globulifera, specialist of seasonally flooded lowlands and S.sp1, specialist of terra firme. These two ecotypes show low genetic differentiation, despite the presence of two apparent phenotypes. A first part of this thesis was to test the presence of local adaptation of this using reciprocal transplant experiment gardens, allowing the understanding of the ecotypes distributions in their natural habitats. Then, this local adaptation in the presence of gene flow, directed me to the regulation of gene methylation in order to see the role this brand of epigenetics can have in the divergence of the ecotypes. In a third part of the thesis, new generation sequencing of the transcriptome ecotypes in reciprocal gardens transplantations allowed me to show the evidence of gene regulation to differentiate the ecotypes. This work thesis is based on phenotype records data, AFLP genotyping and high-throughput sequencing of the transcriptome, in order to show the important value of gene regulation in the divergence of the locally adapted ecotypes, and a weak role of DNA methylation in the establishment of local adaptation.
Connaitre et appréhender les mécanismes de la diversification des espèces est important pour la gestion des écosystèmes, la prévision des impacts des changements climatiques et la compréhension de la biodiversité actuelle et passée. Le but de cette thèse est de comprendre et de déceler les mécanismes génétiques à l’origine de la diversification des espèces en présence de flux de gènes. Cette thèse se focalise sur le modèle biologique Symphonia globulifera, qui compte deux écotypes : le S.globulifera spécialiste de la terra firme et le S.sp1, spécialiste des bas-fonds. Ces deux écotypes montrent une faible différenciation génétique, malgré la présence de deux phénotypes différents.Une première étape a été de mettre en évidence la présence d’une adaptation locale au sein de cette espèce, par le biais d’une expérimentation de jardins de transplantation réciproques, permettant d’expliquer la répartition des écotypes dans leur habitat naturel. Ensuite, dans le but d’identifier les mécanismes sous-jacent à cette adaptation locale, j’ai testé l’hypothèse que la méthylation des gènes pourrait être une marque de l’épigénétique contribuant à la divergence des écotypes, par l’utilisation d’enzyme sensibles à la méthylation dans un protocole de génotypage AFLP. Enfin, un séquençage haut-débit du transcriptome des écotypes en jardins de transplantation réciproques m’a permis de mettre en évidence une expression différentielle des gènes entre les écotypes, qui pourrait expliquer les différences phénotypiques observées entre les écotypes malgré une faible différentiation génétique. Ces travaux de thèse s’appuie, ainsi, sur des données de traits phénotypiques, de génotypage AFLP et de séquençage à haut débit du transcriptome pour montrer la valeur importante de la régulation des gènes dans la divergence des écotypes adaptés localement, et un faible rôle de la méthylation de l’ADN dans l’établissement cette adaptation locale.
https://tel.archives-ouvertes.fr/tel-01405400

NNT : 2015YANE0005
tel-01405400
https://tel.archives-ouvertes.fr/tel-01405400
https://tel.archives-ouvertes.fr/tel-01405400/document
https://tel.archives-ouvertes.fr/tel-01405400/file/these_-_tinaut.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : Reliable measurements of the intensity of the palaeomagnetic field are notoriously difficult to obtain. The approach generally taken is to produce multiple estimates per rock unit and assume that those which meet certain minimum standards of technical quality will combine to produce an accurate mean. However, here, using results produced from a package of 20th century basaltic lava flows from Mount Etna in Sicily, we demonstrate that this approach can fail. In this case, the application of typical sets of selection criteria actually introduces bias into the mean determination that we measure. We demonstrate that this is caused by two types of non-ideal behaviour acting in combination. The first is a result of the multidomain grains that the samples contain and the second is caused by differences in the natural and laboratory cooling rates. We discuss means of avoiding these sources of error in future palaeointensity studies performed on ancient rocks. We also develop a new, more general reliability criterion which is effective here and which we argue should be applied wherever possible in future palaeointensity studies in conjunction with standard criteria. It requires two distinct types of materials which both produce some good-quality palaeointensity measurements and uses their range of overlap to constrain the true palaeointensity. Both the application of this criterion and general reliability considerations require that future palaeointensity studies should measure many samples per cooling unit and that these should be as diverse in terms of their rock magnetic properties and cooling histories as possible.
ISSN: 0012-821X

hal-00407943
https://hal.archives-ouvertes.fr/hal-00407943
DOI : 10.1016/j.epsl.2007.03.017

Éditeur(s) : HAL CCSD
Résumé : The main objective of this thesis was to study the influence of Guianan terra firme rainforests types on medium- and large-sized vertebrates community organization. First, we choose a model species which permitted to develop an appropriate abundance estimation method which take into account the imperfect detection and temporary immigration of mobile species, and to test environmental conditions effects at different spatial scales of analysis. Second, given that bias due to animal detection can be important in the abundance estimation, we determinated the relative role of environmental conditions and species biological traits on detection probability. From this methodological framework, we studied then processes of community organization, by identifying the main determinants involved in community organization, using composition and alpha and beta diversities, and, in a complementary manner, three metrics (taxonomic, functional, and phylogenetic). We sought from these general framework to determinate the relative role of environmental conditions and historical contingency, responsible for the current community organization, and to test the forest refugia hypothesis. Finally, we downscaled the analysis to determinate, and tried to disentangle the effects of environmental conditions and interspecific interactions on species co-occurrence. We used then functional traits to test the relationship between species co-occurrence and similarities.This thesis highlights the important role of historical contingency and facilitation in the structure of regional diversity and the local assembly processes of medium- and large-sized vertebrates, respectively, in French Guiana.
Cette thèse a pour but d’étudier l'influence de l'hétérogénéité des forêts de terre ferme en Guyane sur l'organisation des communautés de moyens et grands vertébrés. Nous avons, d'abord, choisi une espèce modèle afin de déterminer une méthode adéquate d'estimation d'abondance prenant en compte la détection imparfaite et l'immigration temporaire des espèces, et de tester l'effet des conditions environnementales à différentes échelles d'analyse. Puis, partant du constat que les biais dus à la détection dans l'estimation d'abondance pouvaient être importants, nous avons déterminé l'importance relative des conditions environnementales et des traits biologiques des espèces sur la probabilité de détection. A partir de ce cadre d'étude, nous avons étudié la composition et les diversités alpha et beta en utilisant de façon complémentaire les métriques taxonomique, fonctionnelle, et phylogénétique pour déterminer le rôle relatif de l'environnement et de la contingence historique dans l'organisation des communautés, et de tester l’hypothèse des refuges forestiers. Enfin, en descendant dans l'échelle d'analyse, nous avons tenté de démêler l'effet de l'environnement et des interactions interspécifiques sur la cooccurrence des espèces, et utilisé les traits fonctionnels des espèces pour tester le lien entre cooccurrence et similitude fonctionnelle. Cette thèse met en avant les rôles prépondérants de la contingence historique et de la facilitation dans, respectivement, la structuration de la diversité régionale et les processus d’assemblages locaux des communautés de moyens et grands vertébrés en Guyane.
https://tel.archives-ouvertes.fr/tel-01537779

NNT : 2017YANE0004
tel-01537779
https://tel.archives-ouvertes.fr/tel-01537779
https://tel.archives-ouvertes.fr/tel-01537779/document
https://tel.archives-ouvertes.fr/tel-01537779/file/these_thomas_denis.pdf

Résumé : L’aquaculture de crevettes Litopeneus stylirostris, qui est apparue en 1970 en Nouvelle-Calédonie, est devenue une activité économique importante aujourd’hui avec 17 fermes en production et un tonnage de 2000 tonnes en 2004. Situées sur des zones d’arrière mangrove, les fermes exercent une pression sur l’environnement limitrophe, notamment les mangroves. Le rejet des eaux usées des fermes aquacoles dans le lagon semble constituer le principal impact sur l’environnement côtier. La présente étude qui a été lancée dans le cadre du programme ZoNéCo a pour principal objectif l’évaluation d’éventuels impacts de l’aquaculture sur les mangroves de Nouvelle-Calédonie. Elle s’attache : - d’une part à étudier l’évolution des différentes strates végétales d’une mangrove en terme de structure et de superficie par le biais d’analyses diachroniques de photographies aériennes de 3 sites (2 sites jouxtant des fermes aquacoles aux caractéristiques différentes et 1 site vierge) ; - d’autre part à analyser in situ quelques paramètres physico-chimiques (pH, potentiel d’oxydo-réduction, concentrations d’azote et de phosphore totaux dans l’eau, le sédiment et les feuilles de palétuviers) et biologiques (richesse spécifique et densité des organismes mégabenthiques du sédiment à proximité des bassins) sur ces trois sites et voir dans quelle mesure ils peuvent être utilisés comme indicateurs d’impacts. L’analyse diachronique des photographies aériennes depuis 1954 jusqu’en 2004 a mis en évidence sur les sites proches de fermes aquacoles une progression et une densification des palétuviers Rhizophora vers l’intérieur des terres. Cette évolution qui était minime avant construction des fermes est plus marquée depuis. En revanche, peu de changements ont été observés sur le site vierge. Parallèlement, un développement de zones envasées et l’apparition de trouées ont été observés sur les sites exploités depuis l’établissement des fermes. La description de la végétation et les mesures des paramètres physico-chimiques montrent des différences significatives entre sites et au sein même d’un site. La pertinence des méthodologies et l’interprétation des variations intra et inter sites sont discutées. Le faible nombre d’observations ne nous permet pas d’attribuer les variations à un éventuel impact de l’aquaculture. D’autres études seront nécessaires pour valider ces résultats.

Droits : ADECAL/ZONECO
http://archimer.ifremer.fr/doc/00198/30913/29284.pdf
http://archimer.ifremer.fr/doc/00198/30913/