Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
Search String Advanced > Saved Searches >ARTICLE TOOLS Get PDF (3653K) Save to My Profile E-mail Link to this Article Export Citation for this Article Get Citation Alerts Request PermissionsMore Sharing ServicesShare|Share on citeulikeShare on facebookShare on deliciousShare on www.mendeley.comShare on twitter Abstract Article References Cited ByView Full Article (HTML) Enhanced Article (HTML) Get PDF (3653K)AbstractFor the first time, the crystallized remnant of an oceanic ridge magma chamber is documented in the Oman ophiolite. It exists in the centre of a 40 km long monoclinal ridge (Jebel Dihm, Wadi Tayin massif), exposing a full crustal section perpendicular to the spreading direction. New detailed mapping supported by U-Pb zircon geochronology suggests that the active, fast-spreading ridge that died just prior to detachment of the ophiolite is preserved and largely intact. Our observations provide insights into the crystallizing mush zone of a magma chamber, before it crosses the external walls and solidifies as deformed gabbros. Our data provide new constraints on the shape and internal dynamics of a magma chamber, including gabbro subsidence from the floor of a perched melt lens and the limited contribution of sills to crustal accretion. By locating precisely the palaeo-ridge axis, prior full spreading rate estimates can be increased to ~140 km Ma−1.
ISSN: 0954-4879

hal-01121586
https://hal.archives-ouvertes.fr/hal-01121586
DOI : 10.1111/ter.12130

Éditeur(s) : Elsevier
Résumé : Changes in biodiversity may disrupt the ecological functions performed by species assemblages. Hence, we urgently need to examine the implications of biodiversity loss not only in terms of species conservation but also in terms of sustainability of ecosystem services. The ability of protected areas to maintain local species richness has been clearly demonstrated. However, preserving goods and services provided by ecosystems requires not only the conservation of species richness but also the conservation of the most 'original' species, i.e. the ones with the highest average rarity of their attributes which are likely to perform some unique functions in ecosystems. We proposed a new conservation of biological originality (CBO) index as well as associated randomization tests to quantify the ability of piotected areas to maintain viable populations for the most original species. As an application, we used long-term fisheries data collected in the Bonifacio Strait Natural Reserve (BSNR) to determine the species which benefited from the protection reinforcement in 1999. We also estimated a set of 14 ecomorphological functional traits on the 37 fish species caught in the BSNR and we obtained a functional originality value for each species. As a result, we found that functional originality was significantly protected in the fish assemblage of the BSNR: species with the most original functional trait combinations became more abundant after 1999. Our finding suggests that protecting most original species is an insurance against functional diversity erosion in the BSNR. More generally, our new index can be used to test whether protected areas may protect preferentially the most original species and whether restorative management promotes the reestablishment of the most original species with particular habitat requirements. (c) 2008 Elsevier Ltd. All rights reserved.
Biological Conservation (0006-3207) (Elsevier), 2008-06 , Vol. 141 , N. 6 , P. 1569-1580

Droits : 2008 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/2008/publication-4480.pdf
DOI:10.1016/j.biocon.2008.04.002
http://archimer.ifremer.fr/doc/00000/4480/

Éditeur(s) : HAL CCSD Geological Society
Résumé : Gem opals from Wegel Tena, Wollo Province, Ethiopia, occur in Oligocene rhyolitic ignimbrites. They display a unique geochemistry, with some samples yielding the highest Ba concentrations ever recorded. They are generally much richer in chemical impurities than opals from other localities. For example, the sum Al+Fe or the sum Na+Mg+Ca+K+Ba are often higher. These geochemical features make them easy to distinguish from other opals worldwide. We observed strong geochemical variations and some good positive correlations in our samples, such as Al+Fe vs. Na+Mg+Ca+K+Ba, Al vs Ca, or Ba vs Ca. This shows that the crystallography of opal has controlled, at least in part, the incorporation of chemical impurities, although opal is not well-crystallized. In addition, the multimodal distributions of several chemical impurities (e.g. U vs Sr, Al vs Ca, Ba vs Ca, etc.) suggest at least two origins of silica: weathering of feldspars and weathering of volcanic glass. In addition, opals from Wegel Tena contain numerous well-preserved microscopic plant fossils. Moreover, their host rock exhibits features typical of pedogenesis (abundant clays, desiccation cracks, and grain size sorting). We propose that the opals at Wegel Tena formed during the Oligocene period when volcanic emissions stopped for a time long enough to allow weathering of ingimbrites and therefore liberation of silica. This accompanied the formation of soil and development of plant life, and some plants were trapped in opal.
ISSN: 1467-7873

hal-00767555
https://hal.archives-ouvertes.fr/hal-00767555
DOI : 10.1144/1467-7873/10-MINDEP-058

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : We examined tree-soil habitat associations in lowland forest communities at Paracou, French Guiana. We analyzed a large dataset assembling six permanent plots totaling 37.5 ha, in which extensive LIDAR-derived topographical data and soil chemical and physical data have been integrated with precise botanical determinations. Map of relative elevation from the nearest stream summarized both soil fertility and hydromorphic characteristics, with seasonally inundated bottomlands having higher soil phosphate content and base saturation, and plateaus having higher soil carbon, nitrogen and aluminum contents. We employed a statistical test of correlations between tree species density and environmental maps, by generating Monte Carlo simulations of random raster images that preserve autocorrelation of the original maps. Nearly three fourths of the 94 taxa with at least one stem per ha showed a significant correlation between tree density and relative elevation, revealing contrasted species-habitat associations in term of abundance, with seasonally inundated bottomlands (24.5% of species) and well-drained plateaus (48.9% of species). We also observed species preferences for environments with or without steep slopes (13.8% and 10.6%, respectively). We observed that closely-related species were frequently associated with different soil habitats in this region (70% of the 14 genera with congeneric species that have a significant association test) suggesting species-habitat associations have arisen multiple times in this tree community. We also tested if species with similar habitat preferences shared functional strategies. We found that seasonally inundated forest specialists tended to have smaller stature (maximum diameter) than species found on plateaus. Our results underline the importance of tree-soil habitat associations in structuring diverse communities at fine spatial scales and suggest that additional studies are needed to disentangle community assembly mechanisms related to dispersal limitation, biotic interactions and environmental filtering from species-habitat associations. Moreover, they provide a framework to generalize across tropical forest sites.
ISSN: 1932-6203

hal-01260289
https://hal.archives-ouvertes.fr/hal-01260289
PRODINRA : 342930
DOI : 10.1371/journal.pone.0141488

Éditeur(s) : HAL CCSD Geological Society of America
Résumé : In Gobi Altay and Altay, Mongolia, several flat surfaces, worn through basement rocks and uplifted during the ongoing tectonic episode to a similar altitude of 4000 m, suggests disruption of a single large-scale surface. New thermochronology and field data show that the plateau surfaces represent uplifted parts of an ancient peneplain that formed during Jurassic time. The Gobi Altay and Altay flattopped massifs are tectonically and geomorphologically unique. Their preservation for ~150 m.y. implies that no further tectonic movements occurred before the onset of the last deformation episode, 5 ± 3 m.y. ago. It also suggests that very low erosion rates were maintained by a dry climate over millions of years.
ISSN: 0091-7613

hal-00406436
https://hal.archives-ouvertes.fr/hal-00406436
DOI : 10.1130/G23758A.1

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The N-S oriented Raghane shear zone (8 degrees 30') delineates the western boundary of the Saharan metacraton and is, with the 4 degrees 50' shear zone, the most important shear zone in the Tuareg shield. It can be followed on 1000 km in the basement from southern Air, Niger to NE Hoggar, Algeria. Large subhorizontal movements have occurred during the Pan-African orogeny and several groups of granitoids intruded during the Neoproterozoic. We report U-Pb zircon datings (laser ICP-MS) showing that three magmatic suites of granitoids emplaced close to the Raghane shear zone at c. 790 Ma, c. 590 and c. 550 Ma. A comprehensive and detailed (158 sites, more than 1000 cores) magnetic fabric study was performed on 8 plutons belonging to the three magmatic suites and distributed on 200 km along the Raghane shear zone. The main minerals in all the target plutons do not show visible preferential magmatic orientation except in narrow shear zones. The AMS study shows that all plutons have a magnetic lineation and foliation compatible with the deformed zones that are zones deformed lately in post-solidus conditions. These structures are related to the nearby mega-shear zones, the Raghane shear zone for most of them. The old c. 793 Ma Touffok granite preserved locally its original structures. The magnetic structures of the c. 593 Ma Ohergehem pluton, intruded in the Aouzegueur terrane, are related to thrust structures generated by the Raghane shear zone while it is not the case of the contemporaneous plutons in the Assode-Issalane terrane whose structures are only related to the subvertical shear zones. Finally, the c. 550 Ma granite group has magnetic structure related to the N-S oriented Raghane shear zone and its associated NNE-SSW structures when close to them, but NW-SE oriented when further. These NW-SE oriented structures appear to be characteristic of the late Neoproterozoic evolution of the Saharan metacraton and are in relation to the convergence with the Murzuq craton. This evolution reflects the rheological contrast existing along the Raghane shear zone marking the western boundary of the Saharan metacraton.
ISSN: 0040-1951

hal-00429354
https://hal.archives-ouvertes.fr/hal-00429354
DOI : 10.1016/j.tecto.2009.04.022

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Extractives that provide natural resistance to Bagassa guianensis Aubl. heartwood were examined. Soil-bed tests showed that the B. guianensis heartwood resistance was significantly reduced after ethyl acetate extraction, whereas methanol and especially water extractions improved the resistance. The ethyl acetate extract was submitted to a bioguided fractionation, and fractions were tested against one wood-destroying fungal strain (Pycnoporus sanguineus) and two human pathogenic fungal strains (Candida glabrata (yeast) and Trichophyton rubrum (filamentous dermatophyte)). Fraction F7, which exhibited the strongest antifungal activity, was subsequently fractionated by high performance liquid chromatography (HPLC). Six previously described compounds were isolated. Although the two moracins, 6-O-methyl-moracin N (3) and moracin N (4) were the most active against fungal strains with MIC values between 4 and 16 μg ml−1, the isolated compounds showed less or equivalent antifungal activity than the initial fraction. Possible synergism between compounds 3 and 4 and other secondary metabolites have been hypothesized. Our study demonstrated that this extract as a whole might be used as a wood preservation or antimycotic product.
International Biodeterioration and Biodegradation

hal-00694532
https://hal.archives-ouvertes.fr/hal-00694532
DOI : 10.1016/j.ibiod.2011.10.016

Résumé : Nous avons étudié les marqueurs hémorhéologiques, hématologiques et biochimiques chez des sujets drépanocytaires homozygotes SS (HbS/HbS) et hétérozygotes composites SC (HbS/HbC) dans deux cohortes, pédiatriques et adultes, de patients drépanocytaires, et ce, à travers 7 complications récurrentes de la drépanocytose : 2 appartenant au profil hémolytique (l’ulcère de jambes et la glomérulopathie) et 5 appartenant au phénotype visqueux/vaso-occlusif (l’hypertension artérielle, le syndrome thoracique aigu (STA), la crise vaso-occlusive (CVO), la rétinopathie et l’ostéonécrose). Nous avons montré que : 1) une viscosité sanguine et une déformabilité érythrocytaire élevées sont des facteurs de risques de CVO chez les enfants homozygotes ; 2) Une viscosité sanguine élevée est associée à une hypertension artérielle systémique relative chez des adultes SS ; 3) les enfants SC présente une fonction vasculaire mieux préservée que les enfants SS pour faire face à une augmentation de la viscosité sanguine ; 4) les patients adultes SS avec une ostéonécrose présentent une déformabilité érythrocytaire plus élevée que les patients sans ostéonécrose ; 5) une viscosité sanguine élevée est associée à la présence d’une rétinopathie chez les adultes SC mais pas chez les SS ; 6) les patients adultes SS présentant une glomérulopathie ont un taux d’hémolyse élevé, une déformabilité érythrocytaire réduite et des agrégats érythrocytaires très robustes ; 7) les patients adultes SS avec des ulcères de jambes récurrents ont un taux d’hémolyse accru et une déformabilité érythrocytaire réduite. De plus, nos travaux confirment que l’-thalassémie module les propriétés de déformabilité érythrocytaire, mais montrent pour la première fois qu’elle module aussi les propriétés d’agrégation érythrocytaire, et notamment la force des agrégats érythrocytaires. En conclusion, ces travaux permettent de préciser le rôle de la rhéologie sanguine dans un certain nombre de complications de la drépanocytose et d’enrichir le modèle préexistant divisant les complications de la drépanocytose selon 2 phénotypes : hémolytique versus visqueux/vaso-occlusif. Nous montrons pour la première fois que le phénotype hémolytique est caractérisé aussi par des anomalies de la rhéologie du globule rouge : rigidité accrue et agrégats érythrocytaire robustes.
Hemorheological, hemathological, and biochemical marquers of patients with sickle cell anemia (SS) and patients with sickle cell SC disease (SC) were studied in 2 cohorts: children and adults. We focused on 7 recurrent complications: 5 belonging to the viscosity/vaso-occlusion phenotype (systemic hypertension, acute chest syndrome (ACS), vaso-occlusive crisis (VOC), retinopathy and osteonecrosis) and 2 belonging to the hemolytic phenotype (leg ulcer and glomerulopathy). Our results show that 1) high viscosity is associated with increased risk for VOC in SS children; 2) blood viscosity is increased in SS adults with systemic relative hypertension; 3) SC children have preserved vascular function compared to SS children; 4) SS adults with osteonecrosis are characterized by higher red blood cell (RBC) deformability than SS adults without osteonecrosis; 5) high blood viscosity is associated with retinopathy in SC adults but not in SS adults; 6) SS adults affected by glomerulopathy have high hemolytic rate, low RBC deformability and increased RBC aggregates strenght; 7) SS adults with recurrent leg ulcers have high hemolytic rate and reduced RBC deformability. Moreover, our studies shows that alpha-thalassemia modulate RBC deformability and RBC aggregation properties. In conclusion, this work shows for the first time that the hemolytic phenotype is characterized by an abnormal RBC rheology which may play a role in several sickle cell complications.

http://www.theses.fr/2013AGUY0684/document

Résumé : The consciousness of a necessary international co-operation about the fight against marine pollution is relatively recent. In a first time, the concerned states have contracted, at the universal and regional level, some agreements in a punctual way, to organize this fight. From the 1970th, the United States are going to systematize and rationalize this conventional movement aimed to preserve the marine environnement by the working of a standardizing planning liable to be used in some threatened zones, it is the Activities Programm for the regional seas proceeding from the United States Programm for the Environment. For each regional sea reserved by the Programm ; corresponds a whole appliance contained in an Action Plan. Amid each Action Plan, a juridical appliance is foreseen which enables the riverside states to juridically, institutionally and financially organize their co-operation in touch with the International Organizations of the United States system. [NOT CONTROLLED OCR]
La prise de conscience d'une nécessaire coopération internationale en matière de lutte contre la pollution marine est relativement récente. Dans un premier temps, les Etats concernés ont contracté de manière ponctuelle des accords au niveau universel et régional pour organiser cette lutte. A partir des années 1970, les Nations Unies vont systématiser et rationaliser ce mouvement conventionnel destiné à préserver l'environnement marin par la mise en oeuvre d'une planification normative susceptible d'être employée dans un certain nombre de zones menacées, il s'agit du Programme d'activités pour les mers régionales découlant du Programme des Nations Unies pour l'environnement. Pour chaque mer régionale retenue par le Programme correspond un dispositif d'ensemble contenu dans un Plan d'Action. Au sein de chaque Plan d'Action est prévu un dispositif juridique qui permet aux Etats riverains d'organiser juridiquement, institutionnellement et financièrement leur coopération en liaison avec les organisations Internationales du système des Nations Unies. [OCR NON CONTRÔLE]

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1981/rapport-4800.PDF
http://archimer.ifremer.fr/doc/00000/4800/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Highly siderophile elements (Platinum-group elements, Au and Re) are currently assumed to reside inside base metal sulfides (BMS) in the convecting upper mantle. However, fertile lherzolites sampled by Pyrenean orogenic peridotite massifs are unexpectedly rich in 0.5-3 mu m large micronuggets of platinum-group minerals (PGM). Among those, sulfides from the laurite-erlichmanite series (Ru, Os(Ir)S(As)2), Pt-Ir-Os alloys and Pt-Pd-Te-Bi phases (moncheite-merenskyite) are predominant. Not only the BMS phases but also the PGM micronuggets must be taken into account in calculation of the PGE budget of orogenic fertile lherzolites. Laurite is a good candidate for equilibrating the whole-rock budget of Os, it and Ru while accounting for supra-chondritic Ru/Ir-N. Textural relationships between PGMs and BMS highlight heterogeneous mixing between refractory PGMs (laurite/Pt-Ir-Os alloys) inherited from ancient refractory lithospheric mantle and late-magmatic metasomatic sulfides precipitated from tholeiitic melts. "Low-temperature" PGMs, especially Pt-Pd bismuthotellurides should be added to the list of mineral indicators of lithosphere refertilization process. Now disseminated within fertile lherzolites, "lithospheric" PGMs likely account for local preservation of ancient Os model ages (up to 2 Ga) detected in BMS by in-situ isotopic analyses. These PGMs also question the reliability of orogenic lherzolites for estimating the PGE signature of the Primitive Silicate Earth.
ISSN: 0012-821X

hal-00486109
https://hal.archives-ouvertes.fr/hal-00486109
DOI : 10.1016/j.epsl.2009.11.017

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Les littoraux et les îles sont des espaces particulièrement prisés par le développement du tourisme à travers le monde. Entre « désir de rivages » et « île fantasmée », ces espaces convoités, tant pour leurs dimensions tangibles qu’intangibles, s’ouvrent au tourisme. Séduits par les opportunités économiques dont ils ont tant besoin, plus ou moins conscients de leur avantage comparatif et de leurs limites, ils livrent des ressources préservées, des plus vulnérables, autour desquelles se construisent de relations complexes et enjeux.
Coastlines and islands are particularly affected by the development of tourism worldwide. Between "desired costal" and "fantasy Islands", these coveted spaces, with both their tangible and intangible dimensions, are opening to tourism. Attracted by the economic opportunities they so desperately need, and more or less aware of their comparative advantages and limitations, they deliver the most vulnerable preserved resources, the most vulnerable, which are the subject of complex relationships and issues.
Corse
Hainan
Martinique

Droits : info:eu-repo/semantics/openAccess
http://journals.openedition.org/etudescaribeennes/5774

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Roussillon sedimentary Basin (South France) is a complex multi-layered aquifer, close to the Mediterranean Sea facing seasonally increases of water abstraction and salinization issues. We report geochemical and isotopic vertical variability in this aquifer using groundwater sampled with a Westbay System® at two coastal monitoring sites: Barcarès and Canet. The Westbay sampling allows pointing out and explaining the variation of water quality along vertical profiles, both in productive layers and in the less permeable ones where most of the chemical processes are susceptible to take place.The aquifer layers are not equally impacted by salinization, with electrical conductivity ranging from 460 to 43,000 μS·cm− 1. The δ2H–δ18O signatures show mixing between seawater and freshwater components with long water residence time as evidenced by the lack of contribution from modern water using 3H, 14C and CFCs/SF6. S(SO4) isotopes also evidence seawater contribution but some signatures can be related to oxidation of pyrite and/or organically bounded S. In the upper layers 87Sr/86Sr ratios are close to that of seawater and then increase with depth, reflecting water–rock interaction with argillaceous formations while punctual low values reflect interaction with carbonate. Boron isotopes highlight secondary processes such as adsorption/desorption onto clays in addition to mixings. At the Barcarès site (120 m deep), the high salinity in some layers appear to be related neither to present day seawater intrusion, nor to Salses-Leucate lagoonwater intrusion. Groundwater chemical composition thus highlights binary mixing between fresh groundwater and inherited salty water together with cation exchange processes, water–rock interactions and, locally, sedimentary organic matter mineralisation probably enhanced by pyrite oxidation.Finally, combining the results of this study and those of Caballero and Ladouche (2015), we discuss the possible future evolution of this aquifer system under global change, as well as the potential management strategies needed to preserve quantitatively and qualitatively this water resource.
ISSN: 0048-9697

hal-01685219
https://hal-brgm.archives-ouvertes.fr/hal-01685219
DOI : 10.1016/j.scitotenv.2016.05.016

Éditeur(s) : HAL CCSD American Chemical Society
Résumé : International audience
Chlordecone is an organochlorine pesticide that was extensively used in the French West Indies to fight weevils in banana plantations from 1973 to 1993. This has led to a persistent pollution of the environment and to the contamination of the local population for several decades with effects demonstrated on human health. Chlordecone accumulates mainly in the liver where it is known to potentiate the action of hepatotoxic agents. However, there is currently no information on its in situ localization in the liver. We have thus evaluated a matrix-assisted laser desorption ionization (MALDI) imaging quantification method based on labeled normalization for the in situ localization and quantification of chlordecone. After validating the linearity and the reproducibility of this method, quantitative MALDI imaging was used to study the accumulation of chlordecone in the mouse liver. Our results revealed that normalized intensities measured by MALDI imaging could be first converted in quantitative units. These quantities appeared to be different from absolute quantities of chlordecone determined by gas chromatography (GC), but they were perfectly correlated (R(2) = 0.995). The equation of the corresponding correlation curve was thus efficiently used to convert quantities measured by MALDI imaging into absolute quantities. Our method combining labeled normalization and calibration with an orthogonal technique allowed the in situ absolute quantification of chlordecone by MALDI imaging. Finally, our results obtained on the pathological mouse liver illustrate the advantages of quantitative MALDI imaging which preserves information on in situ localization without radioactive labeling and with a simple sample preparation.
ISSN: 0003-2700

hal-01118103
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01118103
PUBMED : 24837422
DOI : 10.1021/ac500313s

Éditeur(s) : HAL CCSD Cambridge University Press (CUP)
Résumé : International audience
This paper presents a synthetic view of the geodynamic evolution of the Zagros orogen within the frame of the Arabia-Eurasia collision. The Zagros orogen and the Iranian plateau preserve a record of the long-standing convergence history between Eurasia and Arabia across the Neo-Tethys, from subduction/obduction processes to present-day collision (from ~ 150 to 0 Ma). We herein combine the results obtained on several geodynamic issues, namely the location of the oceanic suture zone, the age of oceanic closure and collision, the magmatic and geochemical evolution of the Eurasian upper plate during convergence (as testified by the successive Sanandaj-Sirjan, Kermanshah and Urumieh-Dokhtar magmatic arcs), the P-T-t history of the few Zagros blueschists, the convergence characteristics across the Neo-Tethys (kinematic velocities, tomographic constraints, subduction zones and obduction processes), together with a survey of recent results gathered by others. We provide lithospheric-scale reconstructions of the Zagros orogen from ~ 150 to 0 Ma across two SW-NE transects. The evolution of the Zagros orogen is also compared to those of the nearby Turkish and Himalayan orogens. In our geotectonic scenario for the Zagros convergence, we outline three main periods/regimes: (1) the Mid to Late Cretaceous (115-85 Ma) corresponds to a distinctive period of perturbation of subduction processes and interplate mechanical coupling marked by blueschist exhumation and upper-plate fragmentation, (2) the Paleocene-Eocene (60-40 Ma) witnesses slab break-off, major shifts in arc magmatism and distributed extension within the upper plate, and (3) from the Oligocene onwards (~ 30-0 Ma), collision develops with a progressive SW migration of deformation and topographic build-up (Sanandaj-Sirjan Zone: 20-15 Ma, High Zagros: ~12-8 Ma; Simply Folded Belt: 5-0 Ma) and with partial slab tear at depths (~10 Ma to present). Our reconstructions underline the key role played by subduction throughout the whole convergence history. We finally stress that such a long-lasting subduction system with changing boundary conditions also makes the Zagros orogen an ideal natural laboratory for subduction processes.
ISSN: 0016-7568

insu-00616582
https://hal-insu.archives-ouvertes.fr/insu-00616582
https://hal-insu.archives-ouvertes.fr/insu-00616582/document
https://hal-insu.archives-ouvertes.fr/insu-00616582/file/692.full.pdf
DOI : 10.1017/S001675681100046X

Résumé : Le cadre juridique des investissements étrangers en Algérie a été marqué par de profonds changements depuis la promulgation du premier code des investissements, en 1963. Cette mutation n’a pas toujours été en phase avec les processus de développement économique national et le changement du contexte international. Le modèle socialiste de la gestion des affaires économiques qui a prédominé à partir du milieu des années 60 jusqu'au milieu des années 80 a progressivement cédé la place à un retrait graduel de l'Etat du champ économique. On assiste, depuis, à une émergence d’un secteur privé qui tente toujours de trouver sa place, à une vague de privatisations, à une libéralisation du commerce extérieur et à un appel aux capitaux étrangers pour financer le développement économique.Cette volonté manifeste d’accéder à une économie de marché est encore plus perceptible dans le dernier code des investissements de 2001. Ces efforts de mise en conformité du droit interne des investissements avec le droit international des investissements sont relayés par un discours politique offensif.Néanmoins, cet environnement juridique incitatif perd de son attrait lorsqu’on le confronte, soit aux textes promulgués en matière de réglementation du commerce extérieur et la réglementation des changes, soit à l’environnement administratif dans lequel est mis en œuvre l’ensemble de ces textes de lois. Cette confrontation est particulièrement instructive quant à l’insuffisance de cohérence de la politique étatique suivie en matière d’investissement étranger. Ceci révèle la balance d’intérêt des autorités algériennes entre l’augmentation de la contribution des investissements étrangers au potentiel économique et technologique national et la sauvegarde de la souveraineté nationale.Ainsi, le questionnement de la politique législative algérienne d’investissement permet de comprendre les fondements de la doctrine algérienne des investissements étrangers. Cette compréhension favorise l’émergence d’une stratégie qui concilie attractivité et préservation des intérêts publics.
The legal framework for foreign investment in Algeria was marked by profound changes since the enactment of the first investment code in 1963 This change has not always been in line with the process of national economic development and change in the international environment . The socialist model of economic management that prevailed from the mid 60s to mid 80s gradually gave way to a gradual withdrawal of the state from the economic field. There has since been an emergence of a private sector that is still trying to find its place, a wave of privatization, liberalization of foreign trade and to rely on foreign capital to finance the development will économique.Cette Manifest access to a market economy is even more noticeable in the latest investment Code of 2001 These efforts compliance of domestic investment law with the international investment law are supported by a political speech offensif.Néanmoins, the legal environment incentive loses its appeal when confronted or to enactments in regulation of foreign trade and foreign exchange regulations, or administrative environment that is implemented in all these laws. This comparison is particularly instructive about the lack of consistency in state policy with respect to foreign investment. This reveals the balance of interest between the Algerian authorities increasing the contribution of foreign investment to national economic and technological potential and safeguarding sovereignty nationale.Ainsi, questioning the Algerian legislative investment policy allows us to understand the foundations of the Algerian doctrine of foreign investment. This understanding promotes the emergence of a strategy that balances attractiveness and preservation of public interest.

http://www.theses.fr/2012AGUY0785

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We present new, full geomagnetic field vector results from three Neolithic ovens discovered at the archaeological site of Portonovo (Marche, Italy). The discovered structures are a rare example of very well preserved underground ovens from the Early Neolithic period. Standard thermal demagnetization procedures were used to isolate the direction of the Characteristic Remanent Magnetization acquired by the baked clay during the ovens' last firing. The corresponding archaeointensities were determined by the multi-specimen procedure (MSP-DSC) and show a clear intensity low during the Neolithic period. Both directional and intensity results are of high quality, offering the first contribution of full geomagnetic field vector data for this period in Italy. The new data are compared with other contemporaneous data from Europe and with global geomagnetic field models. Independent archaeomagnetic dating of the three ovens was also performed by means of the SCHA.DIF.14k model. The obtained results are in excellent agreement with available radiocarbon dates and confirm that all ovens belong to the Neolithic. These new data importantly enrich our knowledge of the geomagnetic field during the Neolithic period that is poorly documented by data, not only in Italy but also in the whole of Europe and show that archaeomagnetic dating can provide precise results even for prehistoric periods.
ISSN: 0012-821X

hal-01357276
https://hal.archives-ouvertes.fr/hal-01357276
DOI : 10.1016/j.epsl.2016.05.003

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Fromthe Proterozoic to the Quaternary, the evolution of the Earthwas characterised by recurrent periods of glaciation.However, the margins of many ancient ice-sheets are poorly defined on palaeogeographic reconstructions.The extent and outlines of ancient ice sheets can be better understood through careful documentation ofsediments deposited at the ice-sheet margin. An outstanding example is provided herein based on an end-Ordovician archive in Libya (Tihemboka area, Murzuq Basin). The four sets of structures include: i) subglacialglaciotectonic structures and soft sediment deformations from flowing glacier ice, such as intraformational glacialstriae, intraformational deformation (shear planes, sheath folds), normal microfaults, and large-scaleglaciotectonic folds-and-thrusts; (ii) structures resulting from overpressured subglacial (meltwater) flowssuch as clastic dykes and tunnel valleys; (iii) proglacial depositional structures and facies related to highmagnitudemeltwater floods such as sandstone intraclasts, large-scale bedforms resulting from supercriticalflows, climbing-dune cross-stratification and kettle holes; and (iv) deformation structures resulting from freefloating and nonglacier ice such as ice-keel scours and ice-crystal marks. Such a set of structures points to anice-marginal (essentially continental) depositional setting, and provides an excellent suite of criteria to identifymargins of ancient ice sheets in the stratigraphic record. At a regional scale, a reconstruction through time andspace of the related depositional wedge is proposed. This corresponded to a seismic-scale (N120 m in thickness,40 km in length) ice-marginal wedge in front of an essentially warm-based ice-sheet inducing concomitantlarge-scale glaciotectonic deformation, glacial basin and tunnel valley downcuttings. The related ice-front wasassociated with high-energy meltwater flows feeding a network of deeply incised proglacial channels downstreamand, beyond them, a fluvioglacial deltaic system. Shallow ice-marginal permafrost most likely affectedthe depositional wedge. At a larger scale, the Tihemboka ice-marginal wedge is interpreted as related to a stillstandperiod over the Gondwana platform, developed over an estimated interval of a few thousands of years.Based on these data, the conditions that arose in a particularly favourable context for the development, the preservationand the identification of ice-marginal wedges in the geological record are reviewed. Significantmeltwater-derived sediment deposition and aggradation in an accommodation space resulting either frompreglacial inheritance, glacial downcuttings and/or glacio-isostatic lithospheric flexure, or active tectonic subsidence(>1 Myr) are required for their formation and subsequent preservation.
ISSN: 0012-8252

insu-01184739
https://hal-insu.archives-ouvertes.fr/insu-01184739
DOI : 10.1016/j.earscirev.2015.06.006

Éditeur(s) : HAL CCSD Optical Society Optical Society - SOA Publishing
Résumé : International audience
We show that the canonical single frequency sarcomeric SHG intensity pattern (SHG-IP) of control muscles is converted to double frequency sarcomeric SHG-IP in preserved mdx mouse gastrocnemius muscles in the vicinity of necrotic fibers. These double frequency sarcomeric SHG-IPs are often spatially correlated to double frequency sarcomeric two-photon excitation fluorescence (TPEF) emitted from Z-line and I-bands and to one centered spot SHG angular intensity pattern (SHG-AIP) suggesting that these patterns are signature of myofibrillar misalignement. This latter is confirmed with transmission electron microscopy (TEM). Moreover, a good spatial correlation between SHG signature of myofibrillar misalignment and triad reduction is established. Theoretical simulation of sarcomeric SHG-IP is used to demonstrate the correlation between change of SHG-IP and -AIP and myofibrillar misalignment. The extreme sensitivity of SHG microscopy to reveal the submicrometric organization of A-band thick filaments is highlighted. This report is a first step toward future studies aimed at establishing live SHG signature of myofibrillar misalignment involving excitation contraction defects due to muscle damage and disease.
ISSN: 2156-7085

hal-00952823
https://hal.archives-ouvertes.fr/hal-00952823
https://hal.archives-ouvertes.fr/hal-00952823/document
https://hal.archives-ouvertes.fr/hal-00952823/file/boe-5-3-858_002.pdf
DOI : 10.1364/BOE.5.000858

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Background: Ovarian failure (OF) is considered premature if it occurs before the age of 40. This study investigates the genetic aetiology underlying OF in women under the age of 40 years. Methods: We conducted an experimental prospective study performing all genome microarrays in 60 patients younger than 40 years presenting an OF revealed by a decrease of circulating Anti-Mullerian Hormone (AMH) and leading to an oocyte donation program. Results: We identified nine significant copy number variations (CNVs) including candidate genes potentially implicated in reproductive function. These genes are principally involved in cell division and chromosome segregation (SYCE1, CLASP1, CENP-A, CDC16), in ciliary development and/or function (RSPH1, KIF24), are linked with known gonadal genes or expressed in female genital tract (CSMD1, SEMA6D, KIAA1324). Conclusions: Our data strengthen the idea that microarrays should be used in combination with karyotype for aetiological assessment of patients with OF. This analysis may have a therapeutic impact as the identification of new molecular actors for gonadal development or ovarian physiology is useful for the prediction of an ovarian reserve decline and makes possible preventive fertility preservation.
ISSN: 1757-2215

hal-01390979
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01390979
DOI : 10.1186/s13048-016-0272-5
PUBMED : 27716277

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Background information. Marine nematodes belonging to the Stilbonematidae (Desmodoridae) family are described as living in obligatory association with sulfur-oxidizing chemoautotrophic ectosymbionts. The symbiotic bacteria carrying out this chemosynthesis should contain elemental sulfur in periplasmic granules as sulfur granules of chemoautotrophic endosymbionts described in various marine invertebrates. Results. Based on TEM analyses, extracellular bacteria surrounding Eubostrichus dianae possess these spherical periplasmic granules. Few investigative techniques can be used to identify elemental sulfur S8 such as EDXS (energy dispersive X-ray spectroscopy) and EELS (electron energy loss spectroscopy) associated with cryo-fixation of the sample to avoid sulfur loss. These techniques are time consuming, expensive and require technical skills. Raman microspectrometry applied to the analysis of E. dianae allowed us to detect elemental sulfur S8 and confirmed the location of these sulfur clusters in the bacterial coat. In the same way, Raman spectrometry was positively applied to the endosymbiotic bivalve Codakia orbicularis, suggesting that this technique can be used to characterize sulfur in ecto- as well as in endo-symbiotic sulfur-oxidizing bacteria. Conclusions. As Raman spectrometry can be used on living organisms (without preliminary fixation) without sample damage and preserving the molecular structure of the sulfur (denatured during chemical fixation) it represents a very well-adapted investigative tool for biologists. This technique therefore permits us to detect quickly and easily (in a few seconds and on entire living animals) the presence of sulfur compounds in the symbiotic nematode.
ISSN: 0248-4900

hal-00753017
https://hal.univ-antilles.fr/hal-00753017