Éditeur(s) : HAL CCSD American Geophysical Union (AGU)
Résumé : Tectonics, v. 27, p. TC5011, 2008. http://dx.doi.org/10.1029/2007TC002232
International audience
The seismic activity of the Ligurian Basin, the northeastern termination of the western Mediterranean basin, is larger than in surrounding regions, even though recent geodetic studies attest that this area is subject to very low levels of deformation. This basin is an example of a type of passive margins that cannot be considered solely as inert sites of sedimentation and of progressive subsidence and that are reactivated in a compressive pattern; other examples include the Kwanza basin (Angola) and the Brazil margin. We investigated, by means of 2-D thermomechanical modeling, the structural and rheological heterogeneities that can lead to concentration of strain in this marginal basin. We deduced that the deformation of the basin is due to its particular geometric features, narrow and with a thick surrounding continental crust, related to its position at the southern termination of the Alps. This sharp transition, in terms of both geometry and rheological contrast, is a main factor in explaining the weakness of the margin. We discuss the importance of buoyancy forces versus tectonic forces, as well as thermal effects, on the observed reactivation. Influence of contrast in rheology between an oceanic-type crust and continental crust is also studied. Geodynamical implications are proposed for the region. The good agreement between the predicted localized deformation and the observed seismicity distribution should help improve seismic hazard assessment in the region.
ISSN: 0278-7407

hal-00407859
https://hal.archives-ouvertes.fr/hal-00407859
DOI : 10.1029/2007TC002232

Éditeur(s) : HAL CCSD "Giornale Italiano della Ricerca Educativa - Italian Journal of Educational Research".
Résumé : International audience
The aim of this research is to try to explain beliefs of teachers in favour of student retention, beginning with their psycho-pedagogical beliefs in other areas: learning, intelligence, assessment, principle of justice. A questionnaire was administered to 112 primary teachers of the Belgium French. The responses have been processed through factor analysis to construct and validate metric scales. Then, using regression equations, we have tried to predict beliefs about student retention using other categories of beliefs. Finally, we conducted cluster analyses in order to identify groups of teachers, distinguishable by the nature of their beliefs. Two major results emerge from these analyses. On the one hand, it appears that the awareness of research on the effects of repetition influences teachers’ beliefs about this practice. On the other hand, contrary to our assumptions, the other categories of beliefs do not seem to affect teachers’ beliefs about student retention. These results are discussed in relation to the classical theories postulating that beliefs and social representations are organized into a system.
ISSN: 2038-9744

hal-01532840
https://hal.univ-antilles.fr/hal-01532840

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The extent to which Marine Protected Areas (MPAs) benefit corals is contentious. On one hand, MPAs could enhance coral growth and survival through increases in herbivory within their borders; on the other, they are unlikely to prevent disturbances, such as terrestrial runoff , that originate outside their boundaries. We examined the effect of spatial protection and terrestrial sediment on the benthic composition of coral reefs in Saint Lucia. In 2011 (10 to 16 years after MPAs were created), we resurveyed 21 reefs that had been surveyed in 2001 and analyzed current benthic assemblages as well as changes in benthic cover over that decade in relation to protection status, terrestrial sediment influence (measured as the proportion of terrigenous material in reef-associated sediment) and depth. The cover of all ben-thic biotic components has changed significantly over the decade, including a decline in coral and increase in macroalgae. Protection status was not a significant predictor of either current benthic composition or changes in composition, but current cover and change in cover of several components were related to terrigenous content of sediment deposited recently. Sites with a higher proportion of terrigenous sediment had lower current coral cover, higher macroalgal cover and greater coral declines. Our results suggest that terrestrial sediment is an important factor in the recent degradation of coral reefs in Saint Lucia and that the current MPA network should be complemented by measures to reduce runoff from land.
ISSN: 1932-6203

hal-01281152
https://hal-univ-perp.archives-ouvertes.fr/hal-01281152
https://hal-univ-perp.archives-ouvertes.fr/hal-01281152/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01281152/file/journal.pone.0146855.PDF
DOI : 10.1371/journal.pone.0146855

Éditeur(s) : HAL CCSD
Résumé : SilviLaser 2015, La Grande Motte, FRA, 28-/09/2015 - 30/09/2015
International audience
The study provides technical guidelines to optimize sampling design parameters in the context of the implementation of biomass predictive models from airborne lidar data. Parameters under study were those easily controlled when implementing an area-based approach, i.e. lidar pulse density and both field sampling protocols and measurements. Parameters most impacting the model accuracy were identified by conducting a one-factor- at -a-time and a global sensitivity analyses. Number and size of field plot, and plot center position accuracy were identified to be the parameters most impacting model accuracy.
Proceedings of silviLaser 2015. Durrieu S. et Véga, C. (eds)
La Grande Motte, France

hal-01286833
https://hal.archives-ouvertes.fr/hal-01286833
https://hal.archives-ouvertes.fr/hal-01286833/document
https://hal.archives-ouvertes.fr/hal-01286833/file/mt2015-pub00046522.pdf
IRSTEA : PUB00046522

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Improving the prediction of sub-seismic structures and their petrophysical properties is essential for realistic characterization of deformed sandstone reservoirs. In the present paper, we describe permeability contrasts induced by cataclastic deformation bands and faults in porous sandstones (766 data synthesized from field examples and the literature). We also discuss the influence of several factors, including tectonic regime, presence of a fault, burial depth, host sandstone porosity, and grain size and sorting for their initiation and permeability. This analysis confirms that permeability decrease is as a function of grain-crushing intensity in bands. Permeability reduction ranges from very limited in crush-microbreccia of compaction bands to high permeability reduction in cataclasites and ultracataclasites of shear-dominated bands, band clusters and faults. Tectonic regime, and especially normal-fault regime, with its tendency to localize strain and generate faults, is identified as the most important factor, leading to the formation of cataclastic bands with high permeability contrasts. Moreover, moderate burial depth (1–3 km) favors cataclastic bands with high permeability contrasts with respect to the host sandstone. High porosity, coarse-grain size and good grain sorting can slightly amplify the permeability reductions recorded in bands.
ISSN: 0191-8141

hal-01218408
https://hal.archives-ouvertes.fr/hal-01218408
DOI : 10.1016/j.jsg.2015.03.013

Résumé : Les pathologies inflammatoires démyélinisantes primitives du système nerveux central (SNC) sont dominées par deux entités : la sclérose en plaques (SEP) et la neuromyélite optique (NMO). Ces deux pathologies se différencient par : 1. leur phénotype, la NMO se caractérisant par une myélite extensive dans le plan transversal et longitudinal et peu de lésions encéphaliques initiales ; 2. leur sévérité, le pronostic de la NMO étant moins bon que celui de la SEP ; 3. leur mécanisme immunologique, puisque l’immunité humorale domine nettement dans la NMO, cette pathologie répondant peu ou pas aux traitementshabituellement prescrits dans la SEP. Un anticorps sérique (IgG-NMO) a été retrouvé chez les patients atteints de NMO avec une sensibilité de 50-70% et une spécificité de 90-100%. Cet anticorps a pour cible le principal canal hydrique du SNC, l’aquaporine-4 (AQP4), qui se situe principalement sur les pieds astrocytaires jalonnant la barrière hémato-encéphalique. La SEP est relativement familière des neurologues car décrite sur le plan épidémiologique et dans son histoire naturelle depuis plus d’un siècle à travers de larges séries réalisées parfois en population générale. Son approche thérapeutique progresse suite à des essais contrôlés qui s’accumulent depuis maintenant près de 20 ans. Toutefois, la majorité des travaux ont été effectués chez les populations Caucasiennes en raison de sa plus grande fréquence dans ces populations. A l’inverse, la NMO garde encore un relatif mystère à cause de sa relative rareté, l’établissement très récent de critères diagnostiques et une physiopathologie très récemment éclaircie par la découverte de l’IgG-NMO qui a indiscutablement suscité un regain d’intérêt de cette affection. Ainsi, son incidence est quasiment inconnue de même que sa susceptibilité génétique. La progression du handicap de la NMO qu’il soit visuel ou moteur à l’évidence sévère, ne repose toujours pas sur des chiffres précis, la description des lésions neuroradiologiques reste encore très embryonnaire. Enfin, même s’il existe un consensus pour traiter énergiquement les poussées de NMO et les espacer, il n’existe quasiment aucune étude prospective.
Introduction: Aim of the study is to describe épidemiology, phenotype and treatment of demyelinating inflammatory diseases of the central nervous system (CNS) namely multiple sclerosis (MS) and neuromyelitis optica (NMO) in French West Indies.Epidemiology: MS emerged in the French West Indian (FWI) population with an incidence of 1.27/100 000 (CI 95%: 1.16-1.38) for the period 1992-2007 while incidence of NMO remained stable at 0.19/100,000 (CI 95%: 0.15–0.23). Both migration in Metropolitean France (MF) and decrease of sun exposure were risk factors for MS acquisition in FWI. Phenotype and treatment of NMO: NMO is a very rapidly disabling disease with median times to reach DSS 3, 6 and 8 of one year, 8 years and 22 years respectively. However, treatment by plasma exchanges were shown to reduce sequellae of NMO attacks ; mitoxantrone and rituximab reduced significantly annualized relapse rate (ARR) from 1.7 to 0.29 (p<10-4) and from 1,34 to 0,56 (p=0.0005) respectively, improving dramatically natural course of NMO.Phenotype and treatment of MS: Absence of Migration in MF in MS patients was found to be the strongest independent predictive factor of disability progression to DSS 6 (hazard ratio, 2.59; p=0.0002); beside short time to DSS3 (p=0.005), later age at onset (p=0.005), and multi-symptomatic onset (p=0.03). Treatment of MS by interferon beta-1 had a moderate impact in MS while natalizimab proved to be highly effective by reducing drastically ARR and inflammatory parameters on magnetic resonance imaging. Conclusion: Spectrum of demyelinating inflammatory disorders of CNS has reversed in French West Indies with overrepresentation of MS. Agressive therapy is needed to improve prognosis of NMO. Rapidly increasing of its incidence makes MS a new public health problem in French West Indies.

http://www.theses.fr/2012AGUY0511/document