Éditeur(s) : Université des Antilles et de la Guyane
Résumé : The need for an integrated approach to fisheries is now widely affirmed, including the FAO, in particular in the context of tropical artisanal fisheries. These small-scale fisheries, often multispecies are very important in terms of production, employment and food security. However these fisheries and the exploited resources are often characterized by a lack of data making difficult their management within an ecosystem approach, and by the ecological and economic system complexities including trophic and technological interactions. This thesis aims to contribute to the development of bioeconomic tools for small tropical fisheries in a sustainable management perspective based on the ecosystem approach. In this perspective, the French Guiana coastal fishery constitutes an interesting case study. The thesis proposes multi-criteria evaluations, complex bioeconomic models and viable management scenarios for this fishery. At first, multivariate statistical analysis suggests a satisfactory overall status of the fishery in terms of sustainability. However, some performance differences are noted within the fishery, particularly at border areas. Also, management improvements are proposed. Then, through bioeconomic modeling, projections of different fishing scenarios show that, in the long-term, the current exploitation level may not be consistent with the future increase of local demand and a loss of biodiversity may occur. A scenario called "co-viability" reconciling ecological, economic and social objectives, with a high probability of achievement is exhibited. Finally, the comparison of optimal behavior in cooperative and non-cooperative conditions, confirms that harvest levels are greater when actors do not cooperate. Furthermore, it is shown that the state of the ecosystem depends on the fishing strategies and the type of interaction between species. Beyond the diagnosis made for the case study, the method is promising in the context of small tropical fisheries, while the co-viability approach allows finding the exploitation conditions under which ecological and socio-economic sustainability are meet, what the conventional fisheries management generally do not allow.
La nécessité d’une approche intégrée des pêches est actuellement largement affirmée, notamment par la FAO, en particulier dans le contexte des pêcheries artisanales tropicales. Ces pêcheries à petites échelles, souvent multi-spécifiques sont très importantes en termes d’emploi et de production, y compris pour la sécurité alimentaire. Néanmoins ces pêcheries et la biodiversité exploitées sont souvent marquées, d’une part, par le manque de données rendant difficile leur gestion dans le cadre d’une approche écosystémique, d’autre part, par la complexité des systèmes écologiques et économiques sous-jacents incluant interactions trophiques et techniques. Cette thèse contribue à la mise au point d’outils bioéconomiques adaptés aux petites pêcheries tropicales dans la perspective d’une gestion durable des pêches fondée sur l’approche écosystémique. Dans cette perspective, la pêcherie côtière en Guyane Française constitue un cas d’étude particulièrement fécond. La thèse propose ainsi des évaluations multi-critères, des modèles bioéconomiques complexes et des scénarios de gestion viable pour cette pêcherie. Dans un premier temps l’analyse statistique multivariée suggère un statut global satisfaisant de la pêcherie en termes de durabilité. Cependant des différences de performance sont notées au sein de la pêcherie, notamment au niveau des zones frontalières. Aussi des améliorations dans le mode de gestion sont proposées. Ensuite, à travers la modélisation bioéconomique, les projections des différents scénarios de pêche montrent qu’à long terme le niveau d’exploitation actuel peut ne pas être en adéquation avec la future augmentation de la demande locale et qu’une perte de biodiversité peut avoir lieu. Un scenario dit de "co-viabilité" conciliant des objectifs à la fois écologique, économique et social, avec une probabilité de réalisation satisfaisante, est mis en exergue. Enfin, la comparaison des comportements optimaux en situation coopératif et non coopératif, montre dans quelle mesure la viabilité est favorisée quand les acteurs coopèrent. Au-delà du diagnostic apporté pour le cas d’étude, la méthode utilisée s’avère prometteuse dans le contexte des petites pêcheries tropicales, tandis que l’approche de co-viabilité permet de trouver les modalités d’exploitation dans le cadre de compromis entre durabilité écologique et socio-économique, ce que les principes de gestion halieutiques traditionnels ne permettent généralement pas.

Droits : 2013 Université des Antilles et de la Guyane
http://archimer.ifremer.fr/doc/00144/25492/23646.pdf
http://archimer.ifremer.fr/doc/00144/25492/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The full numerical simulation of turbulent flows in the context of industrial applications remains a very challenging problem. One of the difficulties is the presence of a large number of interacting scales of different orders of magnitude, ranging from the macroscopic scale to the Kolmogorov dissipation scale. In order to better understand and simulate these interactions, new algorithms of incremental type have recently been introduced, stemming from the theory of infinite-dimensional dynamical systems (see, e.g., the algorithms of Foias, Jolly et al. (1988), Foias, Manley and Temam (1988), Laminie et al. (1993, 1994), Marion and Temam (1989, 1990), and Temam (1990)). These algorithms are based on decompositions of the unknown functions into a large- and a small-scale component, one of the underlying ideas being to approximate the corresponding attractor. In the context of finite element methods, the decomposition of a solution into small- and large-scale components appears when we consider hierarchical bases (Yserentant, 1986; Zienkiewicz et al., 1982). In the present article we derive several estimates of the size of the structures for the linear and nonlinear terms which correspond to interactions of different hierarchical components of the velocity field, and also their time variation. The one-step time variation of these terms can be smaller than the expected accuracy of the computation. Using this remark, we implement an adaptive spatial and temporal multilevel algorithm which treats differently the small- and large-scale components of the flow. We derive several a priori estimates in order to study the perturbation introduced into the approximated equations. All the interaction terms between small- and large-scale structures are frozen during several time steps. Finally, we implement the multilevel method in order to simulate a bidimensional flow described by the Burgers equations. We perform a parametric study of the procedure and its efficiency. The gain in CPU time is significant and the trajectories computed by our multi-scale method remain close to the trajectories obtained with the classical Galerkin method.
ISSN: 0168-9274

hal-00730710
https://hal.archives-ouvertes.fr/hal-00730710

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 Elsevier
Résumé : Different types of fractures and fault rocks occur within the major normal fault zones bordering the NW of the Neogene Penedes basin (NE Spain). In the southwest part of the basin, the main fault is the Baix Penedes fault that places the Upper Jurassic-Lower Cretaceous dolomicrites of the footwall in contact with the Miocene siliciclastic sediments of the hangingwall. Within the footwall damage zone, different fracture systems and their respective associated breccias and cements have been recognized. Using a combination of structural, petrologic and geochemical analyses, we show that these fracture systems evolved from mainly tectonic to mainly karstic features during the progressive development and upward propagation of the fault. The earlier fractures and associated breccias represent the initial stages of the fault propagation, when the process zone formed around the fault tip was dominated by dilatant fracturing (fractures 1 and dilatant breccias B1). The fluid involved in this early deformation precipitated the dolomite cement Cl, in equilibrium with the host-rock in a closed hydrogeological system. Localization of frictional processes generated cataclasites and ultracataclasites along distinct second-order faults (fractures 2). In these fractures, the dolomite cement C2 precipitated in relation to the incipient opening of the hydrological system to percolating meteoric waters. The later fractures and associated breccias represent the late stages of the fault propagation. These structures (fractures 3, fractures 4 and the dilatant breccias B2) were formed when the extensional deformation reached the surface, resulting in an increasingly open hydrogeological system. At these stages, deposition of the dolomitic sediment DS and precipitation of the calcite cements C3, C4 and C5 show the circulation of freshwaters in a vadose meteoric environment, i.e. in karstic conditions.
ISSN: 0375-6742

hal-00512690
https://hal.archives-ouvertes.fr/hal-00512690
DOI : 10.1016/j.gexplo.2009.11.010

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Serpentinites form by hydration of mantle peridotite and constitute the largest potential reservoir of fluid-mobile elements entering subduction zones. Isotope ratios of one such element, boron, distinguish fluid contributions from crustal versus serpentinite sources. Despite 85% of boron hosted within abyssal peridotite being lost at the onset of subduction at the lizardite-to-antigorite transition, a sufficient cargo of boron to account for the composition of island arc magma is retained (c. 7 μg g− 1, with a δ11B of + 22‰) until the down-going slab reaches the antigorite-out isograd. At this point a 11B-rich fluid, capable of providing the distinctive δ11B signature of island arc basalts, is released. Beyond the uniquely preserved antigorite-out isograd in serpentinites from Cerro del Almirez, Betic Cordillera, Spain, the prograde lithologies (antigorite–chlorite–orthopyroxene–olivine serpentinite, granofels-texture chlorite-harzburgite and spinifex-texture chlorite-harzburgite) have very different boron isotope signatures (δ11B = − 3 to + 6‰), but with no significant difference in boron concentration compared to the antigorite-serpentinite on the low P–T side of the isograd. 11B-rich fluid, which at least partly equilibrated with pelagic sediments, is implicated in the composition of these prograde lithologies, which dehydrated under open-system conditions. Serpentinite-hosted boron lost during the early stages of dehydration is readily incorporated into forearc peridotite. This, in turn, may be dragged to sub-arc depths as a result of subduction erosion and incorporated in a mélange comprising forearc serpentinite, altered oceanic crust and pelagic sediment. At the antigorite-out isograd it dehydrates, thus potentially providing an additional source of 11B-rich fluids.
ISSN: 0009-2541

hal-01172276
https://hal.archives-ouvertes.fr/hal-01172276
DOI : 10.1016/j.chemgeo.2014.03.015

Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : The EUNIS (European Union Nature Information System) habitat classification system aims to provide a common European reference set of habitat types within a hierarchical classification, and to cover all terrestrial, freshwater and marine habitats of Europe. The classification facilitates reporting of habitat data in a comparable manner, for use in nature conservation (e.g. inventories, monitoring and assessments), habitat mapping and environmental management. For the marine environment the importance of a univocal habitat classification system is confirmed by the fact that many European initiatives, aimed at marine mapping, assessment and reporting, are increasingly using EUNIS habitat categories and respective codes. For this reason substantial efforts have been made to include information on marine benthic habitats from different regions, aiming to provide a comprehensive geographical coverage of European seas. However, there still remain many concerns on its applicability as only a small fraction of Europe's seas are fully mapped and increasing knowledge and application raise further issues to be resolved. This paper presents an overview of the main discussion and conclusions of a workshop, organised by the MeshAtlantic project, focusing upon the experience in using the EUNIS habitats classification across different countries and seas, together with case studies. The aims of the meeting were to: (i) bring together scientists with exper_ience_in the use of the EUNIS marine classification and representatives from the European Environment Agency (EEA); (ii) agree on enhancements to EUNIS that ensure an improved representation of the European marine habitats; and (iii) establish practices that make marine habitat maps produced by scientists more consistent with the needs of managers and decision-makers. During the workshop challenges for the future development of EUNIS were identified, which have been classified into five categories: (1) structure and hierarchy; (2) biology; (3) terminology; (4) mapping; and (5) future development. The workshop ended with a declaration from the attendees, with recommendations to the EEA and European Topic Centre on Biological Diversity, to take into account the outputs of the workshop, which identify weaknesses in the current classification and include proposals for its modification, and to devise a process to further develop the marine component of the EUNIS habitat classification. (C) 2012 Elsevier Ltd. All rights reserved.
Marine Pollution Bulletin (0025-326X) (Pergamon-elsevier Science Ltd), 2012-12 , Vol. 64 , N. 12 , P. 2630-2638

Droits : 2012 Elsevier Ltd. All rights reserved.
http://archimer.ifremer.fr/doc/00125/23663/22686.pdf
DOI:10.1016/j.marpolbul.2012.10.010
http://archimer.ifremer.fr/doc/00125/23663/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We have inferred the deformation mechanisms of antigorite by high-resolution EBSD mapping of samples from Cerro del Almirez ultramafic massif (Betic Cordillera, SE Spain). Textural relations and phase diagram calculations constrain the foliation development conditions to the subduction prograde path at up to 600-630 °C and 1.6-1.9 GPa. Deformation was followed by static annealing of antigorite at ca. 680 °C. The Crystal Preferred Orientation (CPO) of antigorite is characterised by a strong alignment of (001) poles normal to the foliation plane and a weaker, but clear, parallelism between [100] axes and the macroscopic lineation defined by the elongation of magnetite aggregates. Analysis of misorientations across subgrains shows predominance of [010] rotation axis, consistent with activation of the [100](001) slip system. However, tilt subgrain boundaries subparallel to (100), probably formed by edge dislocations of this system, are subsidiary. Most subgrain boundaries are subparallel to (001) planes. They are interpreted as (001) twins wherein continuing viscoplastic deformation resulted in a slight increase of the misorientation between the twins. Modelling of the evolution of the antigorite CPO using a lower bound approach and considering different deformation regimes and sets of basal and non-basal slip systems has shown that intensities of [100] and [010] maxima reflect the relative strength of the antigorite [100](001) and [010](001) systems. Activation of other basal or non-basal slip systems does not change significantly the CPO patterns, but results in less concentrated CPO. 3D transpression models better reproduce the CPO of natural antigorite serpentinites. We propose that the widespread occurrence of strong CPO in high-pressure antigorite serpentinite is consistent with deformation by dislocation creep with dominant glide on [hk0](001), together with the activation of twinning, implying that a power law rheology would better account for the mechanical behaviour of antigorite serpentinite deep in the subduction channel and mantle wedge.
ISSN: 0012-821X

hal-00795511
https://hal.archives-ouvertes.fr/hal-00795511
DOI : 10.1016/j.epsl.2012.06.049

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : En étudiant les apprentissages produits par la mise en place des contrats territoriaux d’exploitation (CTE) puis des contrats d’agriculture durable (CAD) à l’île de la Réunion, nous montrons de quelle manière ces outils ont impulsé les prémices d’une agriculture durable dont nous pensons que les apprentissages sont une composante essentielle. Notre travail s’appuie sur des entretiens avec les acteurs du développement rural, techniciens des organisations de développement notamment. Nous montrons que les apprentissages ont été nombreux tant au niveau individuel que collectif, entre conseillers et agriculteurs et entre conseillers d’organismes différents, et relèvent de nature différente (organisationnelle, sociale ou relationnelle).
By studying the trainings produced by the installation of the territorial farm contracts (CTE, Contrat Territorial d’Exploitation) then the sustainable agricultural contracts (CAD, Contrat d’Agriculture Durable) in the Reunion Island, we proved how they encouraged the first steps of a sustainable agriculture. Our work is based on discussions with the actors of rural development, particularly extension technicians of the organizations of development. We establish that the trainings were numerous as well at the individual level as collective, between advisers and farmers and advisers of different organisms, and that they got different nature, organisational, social as well relational).
Réunion

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.3497
http://journals.openedition.org/etudescaribeennes/3497

Éditeur(s) : HAL CCSD Springer Verlag (Germany)
Résumé : International audience
Mount Pinatubo volcano erupted in June 1991 in the main island of Luzon belonging to the Philippines archipelago. Huge economic losses and population exodus have followed. This major crisis has been relayed with other crises due to rainfed lahars which have been supplied with eruption deposits. These lahars have occurred every year since 1991 during the rainy season. They will probably last until 2005. After a brief presentation of the Philippine official response system to disasters, this paper draws up a critical analysis of the different kinds of institutional and social responses deployed to manage the different crisis and post-crisis phases of this event. Based on three viewpoints: from population, media and other actors, this analysis attempts to point out the strengths and weaknesses of the official management system, especially by studying the efficiency and the range of the solutions taken. So, it appears that the management of the June 1991 main crisis (eruption) was a success. On the other hand, difficulties have occurred with lahars risk management. Indeed, these lahars have obliged the authorities to protect and relocate thousands of people. In spite of persistent problems, the management system (monitoring/warning/evacuation) of lahar crises improves year after year. Failures appear especially within the rehabilitation program (protection/rehousing). Many direct (lack of means, preparedness, coordination, dialog,
etc.) and indirect (politico-administrative, socio-economic, cultural contexts) factors come together to lock the wheels of
the institutional response system. They defer the socio-economic start of this vital northern Philippines area.
GeoJournal

halshs-00119436
https://halshs.archives-ouvertes.fr/halshs-00119436
https://halshs.archives-ouvertes.fr/halshs-00119436/document

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We investigated the deformation mechanisms and the seismic properties of 10 eclogite samples from different localities (Alps, Norway, Mali and eastern China) through the analysis of their microstructures and lattice-preferred orientations (LPO). These samples are representative of various types and intensity of deformation under eclogitic metamorphic conditions. Omphacite and garnet LPO were determined from electron backscatter diffraction (EBSD) technique. Garnet appears to be almost randomly oriented whereas omphacite develops strong LPO, characterized by the [001]-axes concentrated sub-parallel to the lineation, and the (010)-poles concentrated sub-perpendicular to the foliation. In order to analyze the deformation mechanisms that produced such omphacite LPO, we compare our observations to LPO simulated by viscoplastic self-consistent numerical models. A good fit to the measured LPO is obtained for models in which the dominant slip systems are 1/2h110i{11 ¯ 0}, [001] {110} and [001] (100). Dominant activation of these slip systems is in agreement with TEM studies of naturally deformed omphacite. Seismic properties of eclogite are calculated by combining the measured LPO and the single crystal elastic constants of omphacite and garnet. Although eclogite seismic anisotropies are very weak (less than 3% for both P-and S-wave), they are generally characterized by a maximum P-wave velocity sub-parallel to the lineation and by a minimum velocity approximately normal to foliation. The mean P-and S-wave velocities are high (respectively, 8.6 and 4.9 km/s). The S-wave anisotropy pattern displays complex relationships with the structural frame but the fast polarization plane generally tends to be parallel to the foliation. Calculated reflection coefficients show that an eclogite/crust interface is generally a good reflector (Rc > 0.1), whereas an eclogite body embedded in the upper mantle would be hardly detectable.
ISSN: 0040-1951

hal-01389715
http://hal.univ-reunion.fr/hal-01389715
http://hal.univ-reunion.fr/hal-01389715/document
http://hal.univ-reunion.fr/hal-01389715/file/Bascou_eclo-sismo_tphy2001_hal.pdf
DOI : 10.1016/S0040-1951(01)00156-1

Éditeur(s) : HAL CCSD ACM
Résumé : International audience
In this study, we use an adapted version of Pitsburgh-like learning classifier system to perform over classification tasks. The Adapted Pittsburgh Classifier System, enhanced with a new mechanism, allows us to consider the classification problems and their treatment by a given LCS in a different manner. Our aim is to exhibit elements in order to prove that, using the action covering mechanism, this system is able to build an inner map of a given classification learning sample. In the context of this paper, this map is built using an intrisic property of Pittsburgh-like CS: the use of various collections of classifiers amongst a unique population.
Proceedings of the 12th annual conference comp on Genetic and evolutionary computation
Portland,Oregon, United States

hal-00520609
https://hal.archives-ouvertes.fr/hal-00520609
DOI : 10.1145/1830761.1830823

Éditeur(s) : HAL CCSD Editions Paralia CFL
Résumé : Les lagunes du Golfe du Lion constituent un patrimoine naturel reconnu ainsi qu'un enjeu essentiel pour les activités économiques locales. Leur évolution morphologique est donc une question importante dans le contexte actuel de changements climatiques et environnementaux. L'analyse de données topo-bathymétriques du système des étangs Palavasiens a permis de mieux cerner son évolution depuis le XVIIIème siècle. Les actions anthropiques et les apports du bassin versant apparaissent comme les facteurs principaux de l'évolution du système. Au cours des 40 dernières années, le système montre une tendance à se combler lentement avec une accumulation moyenne de 1,3 mm/an. Des différences de fonctionnement sur chacun des étangs sont mises en lumière en fonction des forçages naturels et anthropiques locaux. Lagoons of the Gulf of Lion, recognized for their natural heritage, are a key challenge for local economic activities. Their morphological evolution is an important issue in the current context of climate and environmental changes. Analysis of topo-bathymetric data of the Palavasian lakes system has helped to clarify its evolution since the XVIII th century. Human impacts and contributions from the watershed appear to be the main drivers governing the evolutionof the system. Over the past40 years, the system shows a tendency to slowly fill at an accumulation rate of 1.3 mm/year. Differences between lagoons are highlighted according to local natural and anthropogenic forcings.
ISSN: 1760-8716

hal-00854075
https://hal.archives-ouvertes.fr/hal-00854075
DOI : 10.5150/revue-paralia.2011.007

Éditeur(s) : HAL CCSD American Geophysical Union (AGU)
Résumé : International audience
We studied the patterns, rates and evolution of fluvial terraces and fault system during the building process of an intracontinental transpressional mountain in the Gobi-Altay (Mongolia). By analyzing incisions and offsets of fluvial terraces and alluvial fans, we show that the massif has grown by outward migration of thrust faults through time. On the northern flank, the present bounding thrust fault began its activity ~600 ka ago, while a more internal sub-parallel fault was still active until ~200-100 ka. Vertical offset of an alluvial fan abandoned ~100 ka ago allows an estimate of 0.1 mm/yr Upper Pleistocene - Holocene uplift rate. The morphology of the catchment-piedmont system strongly suggests a periodical formation of the alluvial surfaces, controlled by the climatic pulses, at the beginning of the wet interglacial periods. The abandonment of the alluvial terraces lags by several thousand years the abandonment of the alluvial fans, showing a diachronous incision propagating upstream. The incision rate deduced from the different elevations of straths exceeds of one order of magnitude the rock uplift rate. This excess is mostly due to ongoing drainage network growth at the core of the massif, and incision due to alluvial apron entrenchment near the outlet. This implies that fluvial response is mainly controlled by drainage growth, interaction with piedmont and cyclic climatic variations, rather than by rock uplift.
ISSN: 0278-7407

hal-00323558
https://hal.archives-ouvertes.fr/hal-00323558
https://hal.archives-ouvertes.fr/hal-00323558v2/document
https://hal.archives-ouvertes.fr/hal-00323558/file/Vassallo2007.pdf
DOI : 10.1029/2006TC002081

Résumé : Les objectifs de développement de systèmes de culture durables imposent aux acteurs du développement rural une reconception de ces systèmes. Les méthodes de conception actuelles conduisent souvent les chercheurs à être seuls concepteurs alors que parallèlement l'appropriation des innovations dépend fortement de l'implication des autres acteurs. En réponse, des approches participatives sont de plus en plus fréquentes pour pallier à cette difficulté d'appropriation. La méthode développée dans cette thèse -nommée DISCS pour 're-Design and assessment of Innovative Sustainable Cropping Systems' - met en oeuvre un processus de reconception des systèmes de culture par une approche participative tout en développant des outils d'évaluation multicritère. La méthode DISCS s'inscrit dans la lignée de la méthodologie du prototypage mais se différencie par une démarche itérative à trois échelles d'étude (parcelle, exploitation et territoire) afin de s'assurer que les innovations répondent bien aux attentes des acteurs. A chaque étape du processus une évaluation est réalisée à l'aide d'un jeu d'indicateurs. DISCS a été testée sur le système de culture agrumicole en Guadeloupe dans un but de réduire l'utilisation des pesticides. Cinq prototypes de gestion de l'enherbement ont été conçus collectivement puis testés selon les principes d'une approche systémique. Dans cette thèse, nous présentons les premières étapes de reconception du système agrumicole guadeloupéen basée sur la méthode DISCS. Notre travail nous permet de recommander des techniques de gestion de l'enherbement en jeunes vergers d'agrumes répondant aux contraintes actuelles de développement de systèmes de culture durable.
Re-designing sustainable cropping systems has become a major challenge for agricultural researchers and farmers. In most designing methods, researchers are the main, or sometimes the only designers. However, more and more attempts for involving different kinds of stakeholders in participatory approaches have been accounted for. The new method described in this thesis (DISCS for 're-Design and assessment of Innovative Sustainable Cropping Systems') implements a participatory re-designing process. Though founded on the common structure of prototyping methods, this five-step-method differs first by implementing three progress loops, at experimental field, farm then regional scale. Besides, an ongoing progress dynamic is set between research at the experimental station and crop management in farms, in order to ensure that innovative techniques actually match the farmers' expectations. Assessment at each step is performed using a scale-specific set of indicators. The DISCS method was tested on citrus production in Guadeloupe, to develop lower-pesticide sustainable cropping systems. Five weed management prototypes were collectively designed then tested at an experimental station based on the principles of a systematic approach. In this thesis, we present the first stages of citrus cropping system redesigning based on DISCS method. Our work enables us to recommend sustainable weed management techniques for young orchards that correspond to the current constraints facing orchards in Guadeloupe

http://www.theses.fr/2011AGUY0449/document

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The ‘International Intercomparison Exercise of fCO₂ Systems’ was carried out in 1996 during the R/V Meteor Cruise 36/1 from Bermuda/UK to Gran Canaria/Spain. Nine groups from six countries (Australia, Denmark, France, Germany, Japan, USA) participated in this exercise, bringing together 15 participants with seven underway fugacity of carbon dioxide (fCO₂) systems, one discrete fCO₂ system, and two underway pH systems, as well as systems for discrete measurement of total alkalinity and total dissolved inorganic carbon. Here, we compare surface seawater fCO₂ measured synchronously by all participating instruments. A common infrastructure (seawater and calibration gas supply), different quality checks (performance of calibration procedures for CO2, temperature measurements) and a common procedure for calculation of final fCO₂ were provided to reduce the largest possible amount of controllable sources of error. The results show that under such conditions underway measurements of the fCO₂ in surface seawater and overlying air can be made to a high degree of agreement (±1 μatm) with a variety of possible equilibrator and system designs. Also, discrete fCO₂ measurements can be made in good agreement (±3 μatm) with underway fCO₂ data sets. However, even well-designed systems, which are operated without any obvious sign of malfunction, can show significant differences of the order of 10 μatm. Based on our results, no “best choice” for the type of the equilibrator nor specifics on its dimensions and flow rates of seawater and air can be made in regard to the achievable accuracy of the fCO₂ system. Measurements of equilibrator temperature do not seem to be made with the required accuracy resulting in significant errors in fCO₂ results. Calculation of fCO₂ from high-quality total dissolved inorganic carbon (CT) and total alkalinity (AT) measurements does not yield results comparable in accuracy and precision to fCO₂ measurements.
ISSN: 0304-4203

hal-01245605
https://hal.archives-ouvertes.fr/hal-01245605
DOI : 10.1016/S0304-4203(00)00080-3

Éditeur(s) : Elsevier Science Bv
Résumé : The study was conducted to (1) estimate the effects of polyculture of blue shrimp Litopenaeus stylirostris with goldlined rabbitfish Siganus lineatus on production, environmental quality and water and sediment metabolism and (2) to determine if blue shrimp and goldlined rabbitfish polyculture is possible. The experiment was carried out for 12 weeks in a mesocosm system that consisted of 12 circular outdoor mesocosm fiberglass tanks (1.7 m2, 1275 L water volume). Shrimp (2.9 g) were randomly stocked at density of 15 shrimp.m− 2 without rabbitfish (control), with rabbitfish (25.5 g) at low density (1.2 fish.m− 2) (LDRB) and high density (2.4 fish.m− 2) (HDRB). Results indicated that goldlined rabbitfish S. lineatus did not affect shrimp growth performance. At the end of the experiment, the combined shrimp and rabbitfish yields in the LDRB (213 g.m− 2) treatment and the HDRB (295 g.m− 2) treatment were significantly greater (P < 0.05) than the shrimp yield in the control (143 g.m− 2). Most of the water and sediment parameters were similar among treatments. There was no significant difference (P > 0.05) in gross primary productivity and respiration between the HDRB treatment and the control. It was concluded that the polyculture of blue shrimp with goldlined rabbitfish is technically possible without degradation of the environment in the culture system.
Aquaculture (0044-8486) (Elsevier Science Bv), 2014-09 , Vol. 433 , P. 340-347

Droits : 2014 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00198/30968/29344.pdf
DOI:10.1016/j.aquaculture.2014.06.014
http://archimer.ifremer.fr/doc/00198/30968/

Éditeur(s) : HAL CCSD Société géologique de France
Résumé : Late Jurassic platform carbonates of Languedoc (southern France) are deeply incised by Late Miocene canyons, allowing the observation of karst systems filled with sediments containing evidences of marine origin. Field and structural relationships as well as new biostratigraphic data (planktonic foraminifera and calcareous nannofossils) provide a Latest Cretaceous-Earliest Paleocene age for the major karstification and a Paleocene (Danian-Selandian) age for the sedimentary filling. The ≥ 350 m vertical extent of this karst system and its subsequent marine filling gives a minimum amplitude for the base-level variation responsible for the karstification and then the marine flooding events. The observations suggest that at least, two marine successive events occurred in the Late Danian then in Selandian time. The large amplitude of base level is not in agreement with eustatic sea-level change, and the rate of base-level change is too fast for tectonic uplift and subsidence within the tabular, poorly deformed studied area. We propose a model of a silled endoreic basin, which was dessiccated and karstified over hundreds of meters, when it was disconnected from the World Ocean, and later suddently transgressed by the Paleocene sea and the karst flooded, when the bounding sill was submerged. Such a model is similar, although with significant differences, with the later Messinian-Zanclean event that affected the Mediterranean realm.
EISSN: 1777-5817

hal-00767556
https://hal.archives-ouvertes.fr/hal-00767556
DOI : 10.2113/gssgfbull.183.5.425

Éditeur(s) : Elsevier Science Inc
Résumé : The sex-determining system of Crassostrea gigas is still poorly known, especially regarding the potential influence of temperature. In order to address this question, mRNA expressions of actors of the molecular cascade (Cg-DMI, Cg-SoxE, Cg-beta-catenin, Cg-Foxl2/Cg-FoxI2os) and of Oyvlg, a germ cell marker, were investigated by real-time PCR in spat grown at different temperatures (18, 22, 25 and 28 degrees C). In parallel, gonadic differentiation, gametogenesis and sex ratios were assessed by histology at each of these temperatures. Whatever the temperature, Cg-DMI, Cg-SoxE, Cg-beta-catenin and Oyvlg expressions peaked at the same developmental stage, always after Cg-Foxl2/Cg-Foxl2os (around 40-44 dpf for spat grown at 18 degrees C). Temperatures increased the kinetics of first gonadic differentiation and gametogenesis. At 25 degrees C a significant switch occurred in sex ratio towards males and in the balance of expression between male and female genes, in favor of males. A slight gametogenesis disturbance was also observed. These results strengthen the hypotheses about the sex-determining time window and molecular cascade governing the development of C gigas, with notably the involvement of Cg-Foxl2/Cg-Foxl2os in the very early steps. They also suggest an influence of temperature on the oyster's sex determination which, associated to genetic control, would induce a mixed sex determination system (GSD +TSD). (C) 2013 Elsevier Inc. All rights reserved.
Comparative Biochemistry And Physiology A-molecular & Integrative Physiology (1095-6433) (Elsevier Science Inc), 2013-05 , Vol. 165 , N. 1 , P. 61-69

Droits : 2013 Elsevier Inc. All rights reserved
http://archimer.ifremer.fr/doc/00136/24767/22874.pdf
DOI:10.1016/j.cbpa.2013.02.007
http://archimer.ifremer.fr/doc/00136/24767/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Maternal affective disorders are frequently treated with selective serotonin reuptake inhibitor medications (SSRIs); with up to 10% of women being prescribed these medications during pregnancy. Infant development depends on the early serotonergic environment, which is altered by perinatal SSRIs, raising concern about how these medications affect neural outcomes. While clinical and preclinical research suggests an impact of SSRIs on the developing brain, more research is needed to determine the effects on neuroplasticity, the serotonergic system, and the hypothalamic-pituitary-adrenal axis in neural regions mediating behavior. The current work investigated the effects of the SSRI, fluoxetine, on the serotonergic system in the prefrontal cortex (PFC) during pre-adolescence, and changes to synaptic markers and glucocorticoid receptor density in the cingulate cortex (medial PFC) of pre-adolescent and adult Sprague-Dawley male and female rats. To model aspects of Perinatal Depression and maternal anxiety, pre-gestational maternal stress was used resulting in male and female offspring from 4 groups: 1) control, 2) perinatal fluoxetine exposed, 3) pre-gestational maternal stress exposed, and 4) pre-gestational maternal stress + fluoxetine. Perinatal fluoxetine prevented the effects of maternal stress on 5-HT levels and 5-HT turnover ratio in the PFC of pre-adolescent offspring, particularly in females. However, pre-gestational stress reduced synaptophysin and PSD-95 densities in the cingulate cortex, effects that were more pronounced in males. Interestingly, perinatal fluoxetine exposure reduced GR density in adult males in this same brain area. Together, results show differential effects of perinatal SSRIs and pre-gestational maternal stress on neurodevelopment in the PFC of males and females.
ISSN: 0028-3908

hal-01647158
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01647158
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01647158/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01647158/file/Gemmel%20-%20Perinatal%20fluoxetine%20prevents%20the%20effect.pdf
DOI : 10.1016/j.neuropharm.2017.10.009

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
While vertical motion induced by long-term geological loads is often used to estimate the flexural rigidity of the lithosphere, we intend to evaluate the shear rigidity of the lithosphere using horizontal motion. Our approach considers that the rigidity of the lithosphere may be defined as its resistance to horizontal tectonic lateral forces. In this case, a spatial distribution of an effective shear rigidity can be estimated from the analysis of the interseismic velocity fields. We consider the Western United States zone where weakly strained areas (e.g., the Sierra Nevada) are connected with areas of large strain rate (e.g. San Andreas Fault system). By inverting interseismic strain distribution measured by geodetic methods, we infer the effective shear rigidity of the lithosphere. The forward problem is defined using the equations of linear elasticity. The inversion relies on the minimization of the sum of a quadratic measure of the differences between measured and modelled velocity fields. The functional also includes regularization terms for the parameters of the model. The gradient of the functional with respect to the minimization parameters is computed using an adjoint formulation. This permits the treatment of large dimensional minimization problems. Finally, a measure of the uncertainty of our inversion is illustrated through the covariance matrix of the parameters at the optimum. The optimization chart is validated on two synthetic velocity distributions. Then, the effective shear rigidity variations of the Western United States are estimated using the CMM3 interseismic velocities. The inversion displays low effective rigidities along the San Andreas Fault system, the Mojave Desert and in the Eastern California Shear Zone, while rigid areas are found in the Sierra Nevada and in the South Basin and Range. Finally, we discuss the differences between our strain rate and rigidity maps with previously published results for the Western United States.
ISSN: 0040-1951

Droits : http://hal.archives-ouvertes.fr/licences/copyright/
hal-01505024
https://hal.archives-ouvertes.fr/hal-01505024
https://hal.archives-ouvertes.fr/hal-01505024/document
https://hal.archives-ouvertes.fr/hal-01505024/file/Paper_tectophysics.pdf
DOI : 10.1016/j.tecto.2017.03.015