Éditeur(s) : HAL CCSD Taylor & Francis (Routledge)
Résumé : International audience
This article presents the institutional implications and ideologies in the organisation of a Sports Movement for the disabled, whether a physical or sensory handicap, and focusing particular attention on its development in France, linked with international structures. The emergence and development in France of sports organisations for the disabled is based on a different model from that introduced in England by Guttmann through the Stoke Mandeville Games. From the 1960s, both trends, one supported by physicians and the other by individuals concerned with disabilities, structured the International Movement as a contest of negotiations and competition. The objective of rehabilitating paraplegics put in place at Stoke Mandeville gradually gave way to a sport rational and the integration of all types of disability within the Movement. The desire to unite in a single organisation was the driving force of the Movement in its search for dual recognition, on the one hand, as the representative of all physical and sensory deficiencies and, on the other, by the able-bodied sports councils and, in particular, the International Olympic Committee. However, this raised a number of issues inherent to any deficiency when taking into account its specific peculiarities.
ISSN: 0952-3367

hal-01681857
https://hal.archives-ouvertes.fr/hal-01681857
DOI : 10.1080/09523367.2014.931842

Éditeur(s) : HAL CCSD Elsevier
Résumé : Integrated field, LA-MC-ICP-MS geochronology and geochemical data from the Novo Oriente Group have been investigated in order to determine their provenance and possible tectonic setting. This group in the southwestern portion of the Ceara Central Domain, is a well-preserved metavolcanosedimentary sequence, in part exhalative, composed of two distinct formations. The proximal coastal Bonsucesso Formation comprises mainly quartzite and minor basic metavolcanic rocks and is in gradational contact with the distal Caranbas Formation which constitutes a metapelitic-volcanic-carbonate sequence, including metabasic rocks with pillow structure and sheared serpentinized ultrabasic rocks. The youngest detrital zircon found in the quartzite of the Bonsucesso Formation yielded an age of ca. 2.1 Ga and well-defined peaks around 2.2.2.3-2.4 and 2.5 Ga. In addition, zircons from a related metabasalt yielded an upper intercept age of 2083 +/- 28 Ma. We interpret the zircons found in this metabasalt as inherited from the host quartzite. This fact is supported by depleted-mantle Nd model ages (T-DM age) from correlated metabasic and metaultrabasic rocks from other places in the Novo Oriente sequence, which have yielded ages between 1.36 and 1.69 Ga, that is younger than the zircon age obtained in the metabasalt extruded over the Bonsucesso quartzite. Geochemical data of the metasedimentary rocks from the Caraubas Formation indicates a provenance composed of a mixture of felsic and intermediate sources typical of old stable cratons and older continental roots of active tectonic settings. The rocks of the Crania (Medio Coreau Domain) and Bacaja Complexes (southeastern Amazonian Craton) exposed to the west of the Novo Oriente Group, and largely covered by the Phanerozoic Parnaiba intracratonic basin, are the most likely source rocks. Since the precise age of the Novo Oriente Group is not yet well constrained, two distinct settings may be proposed: (1) it may represent a more evolved basin developed from extensional processes during the Mesoproterozoic (ca. 1.5-1.3 Ga); and (2) it could constitute part of the passive margin systems developed during the break-up of the Rodinia crown copyright supercontinent (ca. 0.95-0.8 Ga), associated with a pre-Brasiliano/Pan-African ocean (e.g. Pharusian Ocean). Crown.
ISSN: 1342-937X

hal-00512825
https://hal.archives-ouvertes.fr/hal-00512825
DOI : 10.1016/j.gr.2010.02.001

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The detailed morphology and internal structure of the Calabrian accretionary wedge and adjacent Eastern Sicily margin are imaged in unprecedented detail by a combined dataset of multi-beam bathymetry and high-resolution seismic profiles. The bathymetric data represent the results of 6 recent marine geophysical surveys since 2010 as well as a compilation of earlier surveys presented as a 2 arc-sec (60 m) grid. Several distinct morpho-tectonic provinces are identified including: the deeply incised Malta–Hyblean Escarpment, numerous submarine canyons, broad regions of relatively flat seafloor dominated by fields of sediment waves, the gently undulating anticlinal fold-and-thrust belts of the external Calabrian accretionary wedge and the adjacent portion of the Western Mediterranean Ridge. The Calabrian arc can be divided into 4 domains (from SE to NW): 1) the undeformed Ionian abyssal plain, 2) the external evaporitic wedge, 3) the internal clastic wedge, 4) the Calabrian backstop (Variscan crystalline basement). The Calabrian accretionary wedge can also be divided laterally into two major lobes, the NE- and the SW lobes, and two minor lobes. The kinematics of the limit between the two major lobes is investigated and shown to be sinistral in the external (evaporitic) wedge. A network of radial slip lines within the southernmost external wedge unequivocally demonstrate ongoing dextral displacement of a rigid indenter (representing the corner of the clastic wedge) into the evaporitic wedge thereby confirming the geodynamic model of an active lateral slab tear fault here off eastern Sicily. The slab tear produces a series of major sub-parallel dextral strike-slip faults offshore Mt. Etna and south of the Straits of Messina consistent with the relative motions between Calabria and the Peloritan domain (NE Sicily). Abundant strike-slip faulting, and wide-spread folding and thrusting observed throughout the entire accretionary wedge, indicate regional shortening between the Ionian abyssal plain (foreland) and the Calabrian–Peloritan backstop caused by active subduction.
ISSN: 0012-821X

hal-01523990
https://hal.archives-ouvertes.fr/hal-01523990
DOI : 10.1016/j.epsl.2016.12.020

Résumé : A travers diverses sources et particulièrement des sources orales recueillies auprès d’anciens militants communistes simples adhérents ou responsables et d’articles de la presse communiste martiniquaise, cette thèse cherche à éclairer sur la ferveur militante d’hommes et de femmes de la Martinique, d’une famille politique essentielle dans le courant du XXe siècle.Cette étude parcourt une longue période s’étendant principalement de 1920 à 1971, montrant les débuts balbutiants du communisme à la Martinique, son ascension, sa période florissante et les débuts de son lent déclin. La problématique est d’abord de faire découvrir des Martiniquais dans leur vécu de militant communiste, montrer comment ces hommes et ces femmes s’approprièrent une doctrine, la transformèrent peut-être pour l’adapter à leurs besoins, à leur culture. Il s’agit également d’examiner quelle structure communiste fut mise en place en Martinique, cette organisation était-elle à l’image des fédérations métropolitaines ou était-ce une formation politique spécifique au milieu martiniquais?Ensuite pour mieux appréhender les choix et les parcours, il a fallu arriver à l’identification des modèles, des origines de ce militantisme et la formation des militants. Les référents furent tant des figures propres au marxisme et au socialisme international et national que des personnalités contestataires du milieu politique martiniquais.Puis proposer une lecture des pratiques et des stratégies militantes pour évaluer la qualité et la particularité de cette militance ainsi que les conséquences de l’engagement de ces militants dans différentes sphères. Quelles étaient leurs propositions, pourquoi leurs revendications politiques différaient-elles de celles des autres communistes coloniaux ? Comment expliquer leurs choix d’une nouvelle société plus égalitaire dans un État socialiste mais toujours associé à la France ?Ce travail de recherches positionne cette militance au centre d’une analyse qui explore l’histoire politique et sociale d’une population, en s’appuyant sur d’autres disciplines comme la sociobiographie et les sciences politiques. Il examine le façonnement d’une société par un groupe politique prégnant entre 1920 et 1971, ainsi que les réponses de ce groupe face à différents problèmes politiques et sociaux en privilégiant une approche par les acteurs.
Through various sources, particularly oral sources collected from ancient communists, ordinary members or officials, and articles of martinican Communist press, this thesis shows about the militant fervor of martinican men and women and essential political family in the course of the twentieth century. This study covers a long period extending mainly from 1920 to 1971 showing the early stuttering of communism in Martinique, his ascension, his prosperous period and the beginning of his slow decline. The issue is first to make discover Martinicans in their experience of communist militant, present how these men and women appropriated a doctrine, transformed it perhaps to suit at their needs, at their culture. It is also to consider what communist structure was put in place in Martinique; this organization was it like the metropolitan federations or was it a specific political party? Then to better understand the choices and paths, it’s necessary arrive at identifying mentors, origins of this activism and training of militants. Referents were as figures specific to Marxism and international and national socialism as figures as specific martinican politics. Then offer a reading of practices and activist strategies for assessing the quality and uniqueness of this militancy and the consequences of the commitment of these activists in different spheres. What were their political choices, why their political demands did they differ from others colonial Communists? How to explain their choice of a new society more egalitarian in a socialist state, but always associated with France? This research study positions that militancy in the center of an analysis that explores the political and social history of a population, based on other disciplines such as socio-biography and political-sciences. It examines the shaping of a people by a political significant group between 1920 and 1971, and the proposals of this group face different political and social problems in promoting an approach by the actors.

http://www.theses.fr/2014AGUY0800

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
In order to constrain interpretations of seismic reflection records more effectively, the seismic properties of a middle crustal section exposed in the Saint Barthélémy Massif have been determined. The massif, transected by a 200 m thick shear zone has been systematically sampled for density measurements and modal analysis has been performed in order to define the spatial variations of physical properties. Seismic velocities (Vp, V5, shear wave birefringence), have been measured on five representative samples to 600 MPa and 600°C simultaneously in the three structural directions (X, Y and Z). For two samples, the expep.mental data have been compared with calculated values, based on petrofabric analyses. The Lattice Preferred Orientation (LPO) is determined using universal stage, electron channelling microscopy and neutron diffraction goniometry. Using the experimental and calculated velocity data, we establish a lateral homogeneous anisotropie model.
ISSN: 0954-4879

hal-01389722
http://hal.univ-reunion.fr/hal-01389722
http://hal.univ-reunion.fr/hal-01389722/document
http://hal.univ-reunion.fr/hal-01389722/file/Barruol_aniso_St_Barthelemy_TerraNova1992_hal.pdf
DOI : 10.1111/j.1365-3121.1992.tb00451.x

Éditeur(s) : HAL CCSD
Résumé : Poster
The Lesser Caucasus in Armenia is an active volcanic and tectonic zone which resulted from the collision of the Arabian and the Eurasian plates since Neogene times. The During Quaternary, Lesser Caucasus was uplifted (0.3 mm/yr; Mitchell and Westaway, 1999) and experienced extensional tectonics times. Large lakes developed in graben structures. The diatomitic sequences of the Shamb paleo-lake (South Armenia) offer a rare opportunity to give new insights of Western Asia paleo-climate. Based on macroflora analysis, Bruch and Gabrielyan (2002) proposed a cooling and drying general climate trend through Pleistocene times in relation with a general uplift of the chain. Several questions have to be answer for this poorly investigated region. Did the climate record humid glacials and arid interglacials as suggested northward in Kazakhstan? What are the vegetation and climate responses to orbital parameters and to the monsoon? Moreover the lesser Caucasus is known as the entrance way used by the first hominids in Eurasia during Pleistocene time. How was the environment at this time? We present an integrated palynological, 40Ar/39Ar isotopic and magnetostratigraphic study for the most complete section (Joannin et al., in press). 40Ar/39Ar dating of two volcaniclastic layers provided ages of 1.24 ± 0.03 and 1.16 ± 0.02 Ma (2. Magnetostratigraphic data show that the entire Shamb section is of reversed polarity which correlates with part of the Matuyama period (1.785-1.070 Ma). Pollen assemblages and macroremains diversity revealed an alternation of glacial and interglacial phases that are compared with climate changes inferred from the global isotopic curve. The Shamb section ranges from approximately 1.300 to 1.080 Ma in age (marine isotopic stages 40 to 31). The vegetation of the Lesser Caucasus developed in a mosaic pattern in a Pleistocene continental, mostly arid climate, similar to the present-day climate. The vegetation changes record a dominant climate response to the obliquity orbital parameter. The influence of precession could not be established from the Shamb data. Pollen and macroflora both indicate that glacial periods were cold and dry and that interglacials were warm with local humidity. The early Pleistocene climatic model for Western Asia is thus similar to the climatic model for the Mediterranean area. Bruch, A., Gabrielyan, I.G., 2002. Quantitative data of the Neogene climatic development in Armenia and Nakhichevan. Acta Universitatis Carolinae – Geologica 46, 41–48. Joannin, S., Cornée, J.J., Münch, P., Fornari, M., Vasiliev, J., Krijgsman, W., Nahapetyan, S., Gabrielyan, Y., Ollivier, V., Roiron, P., Chataîgnier, C. In press. Early Pleistocene climatic cycles in continental deposits of the Lesser Caucasus of Armenia inferred from palynology, magnetostratigraphy, and 40Ar/39Ar dating. Earth and Planetary Science Letters. Mitchell, J., Westaway, R., 1999. Chronology of Neogene and Quaternary uplift and magmatism in the Caucasus: constraints from K-Ar dating of volcanism in Armenia. Tectonophysics 304, 157–186.
EGU Eurasian Climate and Tectonics
Vienne, Austria

hal-00481799
https://hal.archives-ouvertes.fr/hal-00481799

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Large sand intrusions often exhibit conical morphologies analogous to magmatic intrusions such as saucer-shaped or cup-shaped sills. Whereas some physical processes may be similar, we show with scaled experiments that the formation of conical sand intrusions may be favoured by the pore-pressure gradients prevailing in the host rock before sand injection. Our experiments involve injecting air into a permeable and cohesive analogue material to produce hydraulic fractures while controlling the pore pressure field. We control the state of overpressure in the overburden by applying homogeneous basal pore pressure, and then adding a second local pore pressure field by injecting air via a central injector to initiate hydraulic fractures near the injection point. In experiments involving small vertical effective stresses (small overburden, or high pore fluid overpressure), the fracturing pressure (lambda(fract)) is supralithostatic and two dipping fractures are initiated at the injection point forming a conical structure. From theoretical considerations, we predict that high values of lambda(fract), are due to strong cohesion or high pore fluid overpressure distributed in the overburden. Such conditions are favoured by the pore pressure/stress coupling induced by both pore pressure fields. The dips of cones can be accounted for elastic-stress rotation occurring around the source. Contrary to magmatic chamber models, the aqueous fluid overpressure developed in a parent sandbody (and prevailing before the formation of injectites) may diffuse into the surrounding overburden, thus favouring stress rotation and the formation of inclined sheets far from the parent source. For experiments involving higher vertical effective stresses (thick overburden or low pore fluid overpressure), the fracturing pressure is lower than the lithostatic stress, and a single fracture is opened in mode I which then grows vertically. At a critical depth, the fracture separates into two dilatant branches forming a flat cone. We make use of a P.I.V. (Particle Imaging Velocimetiy) technique to analyse plastic deformation, showing that these inclined fractures are opened in mixed modes. Close to the surface, they change into steep shear bands where fluids can infiltrate. The final morphology of the fracture network is very similar to the common tripartite architecture of various injection complexes, indicating that different mechanisms may be involved in the formation of dykes. Feeder dykes under the sill zones may open as tensile fractures, while overlying dykes may be guided by the deformation induced by the growth of sills. These deformation conditions may also favour the formation of fluid escape structures and pockmarks. (C) 2011 Elsevier B.V. All rights reserved.
ISSN: 0012-821X

hal-00745640
https://hal.archives-ouvertes.fr/hal-00745640
DOI : 10.1016/j.epsl.2011.10.029

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
In this study we attempt to understand the water storage variations in a karst aquifer on the Larzac Plateau (South of France) using ground-based gravimetry. Surface to 60 m depth gravity measurements are performed three times a year since 2006 down a pothole, in complement to monthly absolute gravity (AG) measurements at three sites. The time variations of the surface to depth (STD) gravity differences are compared with the AG variations. Using a simple Bouguer plate model, we find that the STD gravity differences are very similar to the AG variations. The STD gravity differences are then used to determine apparent density values. These integrative density values are compared with measured grain densities from core samples to obtain an apparent porosity and saturation change representative of the investigated depth. The apparent porosity ranges from 4.8 to 7.3 per cent. We then discuss on the repartition of the apparent physical properties with respect to the epikarst and infiltration zone karst structures. We argue that AG and STD differences monitor epikarst water storage variations. Within this scope, we discuss the fact that seasonal scale water storage variation occurs predominantly in the epikarst.
ISSN: 0956-540X

hal-00413528
https://hal.archives-ouvertes.fr/hal-00413528
DOI : 10.1111/j.1365-246X.2009.04118.x

Éditeur(s) : HAL CCSD Geological Society of London
Résumé : International audience
The mylonitic Cambrian quartzites, Moine Thrust Zone, NW Scotland, have long been used to study microstructural and petrofabric evolution and to develop understanding of grain-scale processes accommodating large-scale displacements. Today, structural geology is entering a new age of understanding of the basic processes involved in microstructural evolution due to the emergence of novel instrumental techniques and theoretical models. It seems apposite therefore to re-evaluate the microstructure of one example of this classic quartz mylonite from the Stack of Glencoul, Assynt, using arguably the most important of these new techniques, electron backscattered diffraction (EBSD). The three-dimensional (3D) microstructure and petrofabric of this rock was analysed using EBSD, to: 1) corroborate previous optical and X-ray texture goniometry measurements; 2) investigate the potential for sampling and/or tectonic sectioning bias that may be introduced inadvertently into any petrofabric analysis; and 3) predict its seismic properties. It is found that microstructures do differ between orthogonal structural sections, leading to variations in strengths of different components in the overall petrofabric that might impact on seismic properties. The results emphasize the true 3D nature of microstructures and petrofabrics, which can be recognized and accommodated more readily by this new generation of analytical techniques.
Continental Tectonics and Mountain Building: The Legacy of Peach and Horne

hal-00565749
https://hal.archives-ouvertes.fr/hal-00565749

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé :  
Cross-species analyses of plant functional traits have shed light on factors contributing to differences in performance and distribution, but to date most studies have focused on either leaves or stems. We extend these tissue-specific analyses of functional strategy towards a whole-plant approach by integrating data on functional traits for 13 448 leaves and wood tissues from 4672 trees representing 668 species of Neotropical trees. Strong correlations amongst traits previously defined as the leaf economics spectrum reflect a tradeoff between investments in productive leaves with rapid turnover vs. costly physical leaf structure with a long revenue stream. A second axis of variation, the 'stem economics spectrum', defines a similar tradeoff at the stem level: dense wood vs. high wood water content and thick bark. Most importantly, these two axes are orthogonal, suggesting that tradeoffs operate independently at the leaf and at the stem levels. By simplifying the multivariate ecological strategies of tropical trees into positions along these two spectra, our results provide a basis to improve global vegetation models predicting responses of tropical forests to global change.
Ecology Letters

hal-01032142
https://hal.archives-ouvertes.fr/hal-01032142
DOI : 10.1111/j.1461-0248.2010.01517.x

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
In the Gulf of Cadiz key segment of the Africa-Iberia plate boundary (North-East Atlantic ocean), three main different modes of tectonic interference between a recently identified wrench system (SWIM) and the Gulf of Cadiz Accretionary Wedge (GCAW) were tested through analog sand-box modeling: a) An active accretionary wedge on top of a pre-existent inactive basement fault; b) An active strike-slip fault cutting a previously formed, inactive, accretionary wedge; and c) Simultaneous activity of both the accretionary wedge and the strike-slip fault. The results we obtained and the comparison with the natural deformation pattern favor a tectonic evolution comprising two main steps: i) the formation of the Gulf of Cadiz Accretionary Wedge on top of inactive, Tethyan-related, basement faults (Middle Miocene to ~ 1.8 Ma); ii) subsequent reactivation of these basement faults with dextral strike-slip motion (~ 1.8 Ma to present) simultaneously with continued tectonic accretion in the GCAW. These results exclude the possibility of ongoing active SWIM wrench system cross-cutting an inactive GCAW structure. Our results also support a new interpretation of the SWIM wrench system as fundamentally resulting from strike-slip reactivation of an old (Tethyan-related) plate boundary.
ISSN: 0025-3227

insu-00643630
https://hal-insu.archives-ouvertes.fr/insu-00643630
https://hal-insu.archives-ouvertes.fr/insu-00643630/document
https://hal-insu.archives-ouvertes.fr/insu-00643630/file/Duarte_etal_2011_MS-1.pdf
DOI : 10.1016/j.margeo.2011.09.014

Éditeur(s) : HAL CCSD
Résumé : International audience
Characterizing the hydraulic properties of heterogeneous and complex aquifers often requires field scale investigations at multiple space and time scales to better constrain hydraulic property estimates. Here, we present and discuss results from the site of Ploemeur (Brittany, France) where complementary hydrological and geophysical approaches have been combined to characterize the hydrogeological functioning of this highly fractured crystalline rock aquifer. In particular, we show how cross-borehole flowmeter tests, pumping tests and frequency domain analysis of groundwater levels allow quantifying the hydraulic properties of the aquifer at different scales. In complement, we used groundwater temperature as an excellent tracer for characterizing groundwater flow. At the site scale, measurements of ground surface deformation through long-base tiltmeters provide robust estimates of aquifer storage and allow identifying the active structures where groundwater pressure changes occur, including those acting during recharge process. Finally, a numerical model of the site that combines hydraulic data and groundwater ages confirms the geometry of this complex aquifer and the consistency of the different datasets. The Ploemeur site, which has been used for water supply at a rate of about 106 m3 per year since 1991, belongs to the French network of hydrogeological sites H+ and is currently used for monitoring groundwater changes and testing innovative field methods.
AGU Fall Meeting 2014
San Francisco, United States

insu-01088596
https://hal-insu.archives-ouvertes.fr/insu-01088596

Éditeur(s) : HAL CCSD Geological Society of London
Résumé : This paper presents the background for the calculation of physical properties of an aggregate from constituent crystal properties and the texture of the aggregate in a coherent manner. Emphasis is placed on the important tensor properties of 2nd and 4th rank with applications in rock deformation, structural geology, geodynamics and geophysics. We cover texture information that comes from pole figure diffraction and single orientation measurements (electron backscattered diffraction or EBSD, electron channelling pattern, Laue pattern, optical microscope universal-stage). In particular, we provide explicit formulae for the calculation of the averaged tensor from individual orientations or from an orientation distribution function (ODF). For the latter we consider numerical integration and an approach based on the expansion into spherical harmonics. This paper also serves as a reference paper for the mathematical tensor capabilities of the texture analysis software MTEX, which is a comprehensive, freely available MatLab toolbox that covers a wide range of problems in quantitative texture analysis, for example, ODF modelling, pole figure to ODF inversion, EBSD data analysis and grain detection. MTEX offers a programming interface which allows the processing of involved research problems as well as highly customizable visualization capabilities; MTEX is therefore ideal for presentations, publications and teaching demonstrations.
Deformation Mechanisms, Rheology and Tectonics: Microstructures, Mechanics and Anisotropy

hal-00688833
https://hal.archives-ouvertes.fr/hal-00688833

Éditeur(s) : HAL CCSD Frontiers
Résumé : International audience
Glufosinate ammonium (GLA) is one of the most widely used herbicides in agriculture. As is the case for most pesticides, potential adverse effects of GLA have not been studied from the perspective of developmental neurotoxicity. Early pesticides exposure may weaken the basic structure of the developing brain and cause permanent changes leading to a wide range of lifelong effects on health and/or behavior. Here, we addressed the developmental impact of GLA by exposing female mice to low dose GLA during both pre- and postnatal periods and analyzed potential developmental and behavioral changes of the offspring during infancy and adulthood. A neurobehavioral test battery revealed significant effects of GLA maternal exposure on early reflex development, pup communication, affiliative behaviors, and preference for social olfactory cues, but emotional reactivity and emotional memory remained unaltered. These behavioral alterations showed a striking resemblance to changes seen in animal models of Autistic Spectrum Disorders. At the brain level, GLA maternal exposure caused some increase in relative brain weight of the offspring. In addition, reduced expression of Pten and Peg3 - two genes implicated in autism-like deficits - was observed in the brain of GLA-exposed pups at postnatal day 15. Our work thus provides new data on the link between pre- and postnatal exposure to the herbicide GLA and the onset of autism-like symptoms later in life. It also raises fundamental concerns about the ability of current safety testing to assess risks of pesticide exposure during critical developmental periods.
ISSN: 1662-5153

hal-01121829
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01121829
PUBMED : 25477793
DOI : 10.3389/fnbeh.2014.00390
PUBMEDCENTRAL : PMC4238406

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Electrical resistivity soundings are used by geophysicists to determine the structure and composition of the Earth's crust and mantle and to explore natural resources (ore, oil, gas, water). Their interpretations in terms of composition and in-situ physical conditions depend mainly on laboratory measurements of electrical conductivity of rocks at simulated crustal conditions of temperature, pressure, saturation and pore pressures. These measurements present a numbers of limitations, in particular, in the case where conductive pore fluids are present, as in the case of deep reservoir conditions, where temperature exceeds 250 A degrees C. Here, we present a new cell capable of measuring electrical conductivity of large saturated samples at confining pressure up to 200 MPa, pore pressure up to 50 MPa, and temperature up to 500 A degrees C. The measurement cell has been developed in a commercial, internally heated, gas pressure apparatus (Paterson press). It is based on the concept of "guard ring" electrode, which is adapted to samples that are jacketed by a very conductive, metallic material. Numerical modeling of the current flow in the electrical cell allowed defining the optimal cell geometry. Calibration tests have been performed on Fontainebleau sandstones saturated with electrolytes of different conductivities, up to 350 A degrees C. The resulting electrical formation factor and temperature dependence of electrical conductivity are in very good agreement with previous studies. This new cell will improve the exploration and exploitation of deep fluid reservoirs, as in unconventional, high enthalpy geothermal fields. In particular, the investigations address possible effects of fluid-rock interactions on electrical resistivity of a reservoir host rock.
ISSN: 0169-3913

hal-00681997
https://hal.archives-ouvertes.fr/hal-00681997
DOI : 10.1007/s11242-011-9846-2

Éditeur(s) : HAL CCSD
Résumé : International audience
Spermatogenesis is a highly sophisticated process involved in the transmission of genetic heritage. It includes halving ploidy, repackaging of the chromatin for transport, and the equipment of developing spermatids and eventually spermatozoa with the advanced apparatus (e.g., tightly packed mitochondrial sheat in the mid piece, elongating of the tail, reduction of cytoplasmic volume) to elicit motility once they reach the epididymis. Mammalian spermatogenesis is divided into three phases. In the first the primitive germ cells or spermatogonia undergo a series of mitotic divisions. In the second the spermatocytes undergo two consecutive divisions in meiosis to produce haploid spermatids. In the third the spermatids differentiate into spermatozoa in a process called spermiogenesis. Paracrine, autocrine, juxtacrine, and endocrine pathways all contribute to the regulation of the process. The array of structural elements and chemical factors modulating somatic and germ cell activity is such that the network linking the various cellular activities during spermatogenesis is unimaginably complex. Over the past two decades, advances in genomics have greatly improved our knowledge of spermatogenesis, by identifying numerous genes essential for the development of functional male gametes. Large-scale analyses of testicular function have deepened our insight into normal and pathological spermatogenesis. Progress in genome sequencing and microarray technology have been exploited for genome-wide expression studies, leading to the identification of hundreds of genes differentially expressed within the testis. However, although proteomics has now come of age, the proteomics-based investigation of spermatogenesis remains in its infancy. Here, we review the state-of-the-art of large-scale proteomic analyses of spermatogenesis, from germ cell development during sex determination to spermatogenesis in the adult. Indeed, a few laboratories have undertaken differential protein profiling expression studies and/or systematic analyses of testicular proteomes in entire organs or isolated cells from various species. We consider the pros and cons of proteomics for studying the testicular germ cell gene expression program. Finally, we address the use of protein datasets, through integrative genomics (i.e., combining genomics, transcriptomics, and proteomics), bioinformatics, and modelling.
Systems Biology in Reproductive Medicine

hal-00877749
https://hal.archives-ouvertes.fr/hal-00877749
DOI : 10.3109/19396368.2012.691943
PUBMED : 22788530

Éditeur(s) : HAL CCSD
Résumé : Patagonia is well known for spectacular occurrences of a variety of glacial-derived landforms and deposits and for a long history of ancient glaciations. In this paper, we first review the diverse evidence that demonstrates the development of glacial-related sedimentary units within the Central Patagonian Cordillera since 7 Ma. Well preserved glacial landforrns at the top surface of mesetas on both sides of the Lago General Carrera-Buenos Aires are described: the Meseta Guenguel to the north, and the volcanic Meseta del Lago Buenos Aires to the south. The latter meseta corresponds to a 3 Ma old, morphologically inverted paleo-piedmont, based on Ar/Ar dates of the uppermost lava flows. It shows evidence of glacier advances to the NE direction. Over a distance of 20 km, glacial landforms observed by remote sensing data and digital elevation model define glacial tongues that were fed by the Cordillera reliefs to the west. These lobes are now beheaded from their westward sources along a morpho-structural corridor that bounds the Meseta del Lago Buenos Aires to the west. These remnants can be correlated with the oldest glacial landforms recognized north of Lago General Carrera-Buenos Aires, on the Meseta Guenguel that form the Chipanque moraine system. From these features it is concluded that the glacial drainage network of Central Patagonia has been strongly modified following relief inversion in response to erosion processes and to tectonic causes. Changes occurred after 3 Ma, from a smooth piedmont surface covered by an extensive ice mantle ending with ample glacial lobes, to the current series of deeply incised glacial valleys such as the Lago General Carrera-Buenos Aires depression. These new data bear important constraints on the history and development of the first glaciations in southern South America.
ANDEAN GEOLOGY

hal-00512682
https://hal.archives-ouvertes.fr/hal-00512682

Éditeur(s) : HAL CCSD
Résumé : The functioning of ecosystems is based on the functional diversity, which is the complementto the species diversity. In the tropical rain forest, the saplings grow in the dense and stratifiedunderstorey. This thesis deals with the diversity of realisation of the support function by thesaplings in this context. The hypotheses are that the race through higher and so brighter levelsconstrains the mechanical security of the saplings with necessary biomass saving and need ofreorientation (gravitropism) and acclimation (mecanoperception and response) processes andthat diversity is thus structured by the species light-demand and affinity for the risk. Using awide sample of 16 species, at the Paracou station, relevant functional traits - risk of not-selfsupportingand gravitropic performance - are defined through adapted modellings whichcombine trunk shape, biomass distribution and wood properties. The traits values varybetween species and also with ontogeny and saplings environment. These variations are dueto elementary traits (shape, biomass, wood) with strong geometrical effects. The less selfsupportingspecies (low mechanical security) have the highest gravitropic performances andare also the most light-demanders. A species, Tachigali melinonii, distinguishes itself bystrong slendernesses and a frequent not-self-supporting habit letting suppose a strongadaptability to its mechanical environment. An experiment (growth response to staking),however, did not provide the expected results whereas the species with lower risks, Dicoryniaguianensis, reacted more.
Le fonctionnement des écosystèmes repose sur la diversité fonctionnelle, complément de ladiversité spécifique. En forêt tropicale humide, les jeunes arbres croissent en sous-bois denseet stratifié. Cette thèse porte sur la diversité de réalisation de la fonction biomécanique desoutien. Les hypothèses sont que la "course" vers les strates plus éclairées contraint lasécurité mécanique des jeunes arbres, avec de nécessaires économies de matière et recours àdes processus de réparation (gravitropisme) et d'acclimatation (mécanoperception et réponse),et que la diversité est donc structurée par le besoin en lumière et l'affinité pour le risque desespèces. Avec un échantillon de 16 espèces sur le dispositif de Paracou, des traits fonctionnelspertinents - risque de non-autoportance et performance gravitropique - sont définis au traversde modélisations adaptées qui combinent forme des troncs, répartition des masses etpropriétés du bois. Ces traits varient entre espèces mais aussi avec le développement etl'environnement des arbres. Ces variations sont dues aux variations des traits élémentaires(forme, masses, bois) avec de forts effets géométriques. Les espèces les moins autoportantes(faible sécurité) ont les plus fortes performances gravitropiques. Ce sont aussi les plusdemandeuses de lumière. Une espèce Tachigali melinonii se distingue par de fortsélancements et une fréquente non-autoportance laissant supposer une adaptabilité forte àl'environnement mécanique. Une expérimentation (réponse de croissance au tuteurage) n'acependant pas abouti aux résultats supposés puisque c'est au contraire l'espèce à faible risque,Dicorynia guianensis, qui s'est montrée plus réactive.
https://tel.archives-ouvertes.fr/tel-00272100

tel-00272100
https://tel.archives-ouvertes.fr/tel-00272100
https://tel.archives-ouvertes.fr/tel-00272100/document
https://tel.archives-ouvertes.fr/tel-00272100/file/TheseJaouen.pdf

Éditeur(s) : HAL CCSD Oxford University Press (OUP): Policy B - Oxford Open Option B
Résumé : Variability of leaf traits related to photosynthesis was assessed in seedlings from 14 tree species growing in the tropical rain forest of French Guiana. Leaf photosynthetic capacity (maximum rate of carboxylation and maximum rate of electron transport) was estimated by fitting a biochemical model of photosynthesis to response curves of net CO2 assimilation rate versus intercellular CO2 mole fraction. Leaf morphology described by leaf mass per unit leaf area (LMA), density and thickness, as well as area- and mass-based nitrogen (N) and carbon (C) concentrations, were recorded on the same leaves. Large interspecific variability was detected in photosynthetic capacity as well as in leaf structure and leaf N and C concentrations. No correlation was found between leaf thickness and density. The correlations between area- and massbased leaf N concentration and photosynthetic capacity were poor. Conversely, the species differed greatly in relativeNallocation to carboxylation and bioenergetics. Principal component analysis (PCA) revealed that, of the recorded traits, only the computed fraction of total leafNinvested in photosynthesis was tightly correlated to photosynthetic capacity.We also used PCAto test to what extent species with similar shade tolerances displayed converging leaf traits related to photosynthesis. No clear-cut ranking could be detected among the shade-tolerant groups, as confirmed by a one-way ANOVA.We conclude that the large interspecific diversity in photosynthetic capacity was mostly explained by differences in the relative allocation of N to photosynthesis and not by leafNconcentration, and that leaf traits related to photosynthetic capacity did not discriminate shade-tolerance ranking of these tropical tree species.
ISSN: 0829-318X

hal-01031522
https://hal.archives-ouvertes.fr/hal-01031522