Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We present an integrated study of geochemistry, petrofabrics and seismic properties of strongly sheared eclogites from the Chinese Continental Scientific Drilling (CCSD) project in the Sulu ultrahigh-pressure (UHP) metamorphic terrane, eastern China. First, geochemical data characterize diverse protoliths of the studied eclogites. The positive Eu- and Sr-anomalies, negative Nb anomaly and flat portion of heavy rare earth elements in coarse-grained rutile eclogites (samples B270 and B295) suggest a cumulate origin in the continental crust, whereas the negative Nb anomaly and enrichment of light rare earth elements in retrograde eclogites (samples B504, B15 and B19) imply an origin of continental basalts or island arc basalts. Second, P-wave velocities (V-p) of three typical eclogite samples were measured under confining pressures up to 500 MPa and temperatures to 700 degrees C. At 500 MPa and room temperature, the mean V-p reaches 8.50-8.53 km/s in samples B270 and B295 but drops to 7.86 km/s in sample B504, and the P-wave anisotropy changes from 1.7-2.7% to 5.5%, respectively. The pressure and temperature derivatives of V-p are larger in the retrograde eclogite than in fresh ones. Third, the electron backscatter diffraction (EBSD) measurements of the eclogites reveal random crystal preferred orientation (CPO) of garnet and pronounced CPO of omphacite, which is characterized by a strong concentration of [001]-axes sub-parallel to the lineation and of (010)-poles perpendicular to the foliation. The asymmetric CPO of omphacite in sample B270 recorded a top-to-the-south shear event during subduction of the Yangtze plate. The calculated fastest V-p is generally sub-parallel to the lineation, but a different deformation environment during exhumation could form second-order variations in omphacite CPO and affect the V-p distribution in eclogites (e.g., the fastest V-p is at similar to 35 degrees from the foliation in sample 13295). Comparison between measured and calculated seismic properties indicates that the CPO of omphacite controls the seismic anisotropy of eclogites at high pressure, and compositional layering and retrograde minerals will increase the anisotropy. Calculated P-wave velocities agree well with velocities measured at 500 MPa and room temperature for fresh eclogites, but much higher than those of retrograde eclogite. As a case study, the laboratory-derived V-p-P and V-p-T relationships were used to estimate P-wave velocities of eclogites and peridotites beneath the Western Superior Province, Canada. The results indicate that besides the fabric-induced anisotropy, the direction dependence of pressure and temperature derivatives of V-p can significantly increase seismic anisotropy of eclogites with depth, which results in eclogites being an important candidate for the seismic anisotropy in the upper mantle. Due to their very high density and velocity, garnet-rich eclogites within peridotite could be detected in seismic reflections in subduction zones.
ISSN: 0040-1951

hal-00463512
https://hal.archives-ouvertes.fr/hal-00463512
DOI : 10.1016/j.tecto.2008.09.027

Éditeur(s) : HAL CCSD American Geophysical Union (AGU)
Résumé : International audience
The Pyrenean peridotites (lherzolites) form numerous small bodies of subcontinental mantle, a few meters to 3 km across, exposed within the narrow north Pyrenean zone (NPZ) of Mesozoic sediments paralleling the north Pyrenean Fault. Recent studies have shown that mantle exhumation occurred along the future NPZ during the formation of the Albian-Cenomanian Pyrenean basins in relation with detachment tectonics. This paper reviews the geological setting of the Pyrenean lherzolite bodies and reports new detailed field data from key outcrops in the Bearn region. Only two types of geological settings have to be distinguished among the Pyrenean ultramafic bodies. In the first type (sedimented type or S type), the lherzolites occur as clasts of various sizes, ranging from millimetric grains to hectometric olistoliths, within monogenic or polymictic debris flow deposits of Cretaceous age, reworking Mesozoic sediments in dominant proportions as observed around the Lherz body. In the second type (tectonic type or T type), the mantle rocks form hectometric to kilometric slices associated with crustal tectonic lenses. Both crustal and mantle tectonic lenses are in turn systematically associated with large volumes of strongly deformed Triassic rocks and have fault contacts with units of deformed Jurassic and Lower Cretaceous sediments belonging to the cover of the NPZ. These deformed Mesozoic formations are not older that the Aptian-early Albian. They are unconformably overlain by the Albian-Cenomanian flysch formations and have experienced high temperature-low pressure mid-Cretaceous metamorphism at variable grades. Such a tectonic setting characterizes most of the lherzolite bodies exposed in the western Pyrenees. These geological data first provide evidence of detachment tectonics leading to manle exhumation and second emphasize the role of gravity sliding of the Mesozoic cover in the preorogenic evolution of the Pyrenean realm. In the light of such evidence, a simple model of basin development can be inferred, involving extreme thinning of the crust, and mantle uprising along a major detachment fault. We demonstrate coeval development of a crust-mantle detachment fault and generalized gravitational sliding of the Mesozoic cover along low-angle faults involving Triassic salt deposits as a tectonic sole. This model accounts for the basic characteristics of the precollisional rift evolution in the Pyrenean realm.
ISSN: 0278-7407

hal-00512818
https://hal.archives-ouvertes.fr/hal-00512818
DOI : 10.1029/2009TC002588

Éditeur(s) : HAL CCSD Springer Verlag (Germany)
Résumé : International audience
The influence of magnetic interactions on the anisotropy of magnetic susceptibility (AMS) have been largely studied by several theoretical models or experiments. Numerical models have shown that when magnetostatic interactions occur, the distributions of particles over the volume rather than their individual orientations control the AMS. We have shown recently from a comprehensive rock magnetic study and from a theoretical 2-dimensional (2-D) model that single domain particles closely packed in globule aggregates could produce strong local random interaction magnetic fields which could influence the magnetic susceptibility and decrease the degree of anisotropy. In this paper, we first present in detail this 2-D theoretical model and then we extend it to the 3-D case. The possible distribution function of the magnetostatic interaction fields comprises two extreme states: it is either isotropic or ordered. The former case corresponds to the thermal-demagnetized state while the second case corresponds to the alternating field (AF) demagnetized state. We show that when easy axes of magnetization are not uniformly distributed, the degree of anisotropy decreases as the interaction field increases in both AF- and thermal-demagnetized states in 2-D and 3-D geometry. Thus we conclude that random magnetic fields generated by a random arrangement of magnetic particles over the sample volume decrease the degree of anisotropy of AMS and may alter the magnetic fabric.
ISSN: 0039-3169

hal-00758113
https://hal.archives-ouvertes.fr/hal-00758113
https://hal.archives-ouvertes.fr/hal-00758113/document
https://hal.archives-ouvertes.fr/hal-00758113/file/SGEG-2012-HAL.pdf
DOI : 10.1007/s11200-010-9097-7

Éditeur(s) : HAL CCSD EDP Sciences
Résumé : International audience
We show that the so-called low-regret (or least-regret) control by J. L. Lions [8] fits on the control of ill-posed problems. At each time, we give the characterization of the so-called no-regret control by means of singular optimality systems. For the backward heat ill-posed problem, no Slater hypothesis is assumed on the admissible set of controls U ad. This work is two pieces, and two methods are considered : the regularization method and the null-controllability method. For the first method, a zero order corrector is used, while for the second method, the passage to the limit is easy. The results presented here generalize the works in [2, 3] to the no-regret control. Résumé. On montre que le contrôlè a moindres regrets de J. L. Lions [8] est bien adapté pour le contrôle des desprobì emes mal posés. A chaque fois, on donne une caractérisation du contrôle sans regret par le moyen de systèmes d'optimalité singuliers. Pour leprobì eme de chaleur rétrograde mal posé, aucune hypothèse de type Slater sur l'ensemble des contrôles admissibles U ad n'est nécessaire. Ce travail est divisé en deux parties, et deux méthodes sont considérées: la méthode de régularisation et celle de la contrôlabilitécontrôlabilitéà zéro. Pour lapremì ere méthode, un correcteur d'ordre zéro est utilisé, alors que pour la seconde méthode le passagè a la limite est simple. Les résultats présentés ici généralisent les travaux dans [2, 3] au contrôle sans regret.
ISSN: 1270-900X

Droits : info:eu-repo/semantics/OpenAccess
hal-01683792
https://hal.univ-antilles.fr/hal-01683792
https://hal.univ-antilles.fr/hal-01683792/document
https://hal.univ-antilles.fr/hal-01683792/file/proc071705.pdf

Éditeur(s) : HAL CCSD Lippincott, Williams & Wilkins
Résumé : International audience
Regarding nerves as simple cables and electrical conduits is a gross error that does not allow us to understand the anomalies and disorders observed postoperatively. Instead, nerves should be seen as a living tissue of which physiological regulation is as complex as that of the blood-brain barrier. This review describes the basic structure and functions of this blood-nerve barrier and highlights the mechanisms of its breakdown and the resultant disorders. For clinical practice, it is important to note that the diffusion of molecules from the perineurium or from the blood is very limited, and so the blood-nerve barrier is a major pharmacologic barrier. Any stress upon neural physiological balance, particularly the terminal vascular blood supply, will induce the classic inflammatory cascade. Due to the complexity of the vascular system, nerve ischaemia will occur more quickly when the terminal blood supply is compromised. This blood supply can adapt in a variety of ways but when these possibilities of adaptation are exceeded, tissue ischaemia may be more extensive. Also, even after the initial injury has subsided, inflammation can cause a secondary insult. This could be particularly important in some patients with subclinical neuropathy.
ISSN: 0265-0215

hal-01477207
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01477207
DOI : 10.1097/EJA.0000000000000590
PUBMED : 28146457

Éditeur(s) : Université de Montpellier II
Résumé : The sea bass, Dicentrarchus labrax, has been subjected to intensive aquaculture on the Mediterranean cost for ten years. Marine fish hatcheries are key factors in the aquaculture field, and face different pathologies, especially one of viral origin (nodavirus) that could challenge their feasibility. Consequently, we have tried to provide some data on larvae and spawning stocks. Firstly, we have studied the immunoglobulins, components of the specific humoral immunity, and their role as antibodies. On adult basses, these immunoglobulins are tetrameric molecules with high molecular weight (850 kD), made of heavy (H) - 80 kD and light (L) - 26 kD chains. In the eggs, simplest forms such as monomeric or dimeric are brought to the fore; they are located under the chorionic membrane. Secondly, we have studied the development of the immunity system on larvae, preparing IgM assays with ELISA method, the study on the organogenesis of the main lymphoid organs, and using flow cytometry for the ontogenesis of IgM producing cell. Based on this experience, we can propose a date for the immunocompetence onset of the bar, i.e. from the 54th day of the hatchery phase. Finally, we made the most of these different results to study a viral pathology (nodavirus) in spawners and larvae. We defined an experimental contamination model for larvae and eggs, and we highlighted that eggs born from vaccinated hen fishes were protected against the nodavirus.
Le bar, Dicentrarchus labrax, fait l'objet d'une aquaculture intensive sur le littoral Méditerranéen depuis une dizaine d'années. Les écloseries marines représentent un des maillons clefs de cette filière aquacole, et sont confrontées à différentes pathologies, dont une d'origine virale (nodavirus), pouvant remettre en cause leur faisabilité. Aussi, nous avons tenté d'apporter quelques données concernant la protection des larves et des géniteurs reproducteurs. Dans un premier temps, nous avons étudié les immunoglobulines, éléments de l'immunité spécifique humorale ainsi que leur rôle anticorps. Chez les bars adultes ces immunoglobulines sont des molécules tétramériques de haut poids moléculaire (850 kD), composées de chaînes lourdes (H) de 80 kD et légères (L) de 26 kD. Dans les oeufs, des formes plus simples, monomériques ou dimériques, sont mises en évidence et sont localisées sous la membrane chorionique. Dans un second temps, nous avons étudié la mise en place du système immunitaire spécifique chez les larves, en effectuant le dosage des IgM par ELISA, l'étude de l'organogenèse des principaux organes lymphoïdes, puis celle de l'ontogenèse des cellules productrices d'IgM par cytométrie de flux. L'ensemble de cette étude nous permet de proposer une date d'acquisition de l'immunocompétence à partir du 54ème jour d'élevage chez le bar. Enfin, ces différents résultats ont été mis à profit dans le cadre d'une pathologie virale (nodavirus) touchant les reproducteurs et les larves. Après avoir défini un modèle de contamination expérimental des larves et des oeufs, nous avons mis en évidence une protection des oeufs lorsque ceux-ci proviennent d'une femelle vaccinée (vaccin expérimental) contre le nodavirus.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1997/these-1265.pdf
http://archimer.ifremer.fr/doc/00000/1265/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Second harmonic generation (SHG) microscopy is a powerful tool for studying submicron architecture of muscles tissues. Using this technique, we show that the canonical single frequency sarcomeric SHG intensity pattern (SHG-IP) of premetamorphic xenopus tadpole tail muscles is converted to double frequency (2f) sarcomeric SHG-IP in metamorphic climax stages due to massive physiological muscle proteolysis. This conversion was found to rise from 7% in premetamorphic muscles to about 97% in fragmented muscular apoptotic bodies. Moreover a 66% conversion was also found in non-fragmented metamorphic tail muscles. Also, a strong correlation between predominant 2f sarcomeric SHG-IPs and myofibrillar misalignment is established with electron microscopy. Experimental and theoretical results demonstrate the higher sensitivity and the supra resolution power of SHG microscopy over TPEF to reveal 3D myofibrillar misalignment. From this study, we suggest that 2f sarcomeric SHG-IP could be used as signature of triad defect and disruption of excitation–contraction coupling. As the mechanism of muscle proteolysis is similar to that found in mdx mouse muscles, we further suggest that xenopus tadpole tail resorption at climax stages could be used as an alternative or complementary model of Duchene muscular dystrophy.
ISSN: 1047-8477

hal-01134174
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134174
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134174/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134174/file/Recher%20et%20al_JSB-2015_hal.pdf
DOI : 10.1016/j.jsb.2015.03.003

Éditeur(s) : EDP Sciences
Résumé : Market position and its evolution were analysed in nine key fish and cephalopod species subject to long-term changes, using the Bay of Biscay fisheries as a case study. Although such long term changes have already been documented, and in some cases shown to be related to the impacts of fishing, changes in the physical environment, or both, relatively little work has been devoted to their potential consequences in economic terms. The nature and extent of these consequences was determined in the present study by looking at the composition of the affected fish production, and the status of different fish products on the markets. We propose a methodology to characterize market position for this set of nine species. The selected species represent a significant part of the gross turnover of French fishing fleets operating in the bay. These species were characterized in terms of their potential sensitivity to fishing and changes in environmental conditions due to global warming. We separated species potentially positively (Engraulis encrasicolus and Lophius budegassa) and negatively affected (Pollachius pollachius and Lophius piscatorius) by warming. Evolution of the value of production of the nine species was then depicted using analysis of macro-economic index (production and potential consumption) and price indices. This revealed the relatively high sensitivity of domestic production to the market crisis that occurred in France in the early 1990s, compared to imported and exported products. The relative position of individual species, with respect to the market and its evolution between 1990 and 2005, was analyzed by multi-factorial analysis. Results derived from the analysis clearly distinguish two groups of species, the first characterized by higher prices (monkfish, Nephrops, sole, seabass) and the second by larger volumes available on the French market (pollack, hake, anchovy, sardine, cuttlefish). We conclude that a major part (69 to 87%) of the gross turnover associated with catches of these fish species in the Bay of Biscay remains potentially unaffected by long-term changes related to climate.
Aquatic Living Resources (0990-7440) (EDP Sciences), 2008-07 , Vol. 21 , N. 3 , P. 307-316

Droits : EDP Sciences, IFREMER, IRD 2008
http://archimer.ifremer.fr/doc/2008/publication-4716.pdf
DOI:10.1051/alr:2008047
http://archimer.ifremer.fr/doc/00000/4716/

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : International audience
Alveolar proteinosis (AP) is a rare disease characterized by alveolar accumulation of surfactant components, which impairs gas exchange. AP is classified into three groups: auto-immune AP defined by the presence of plasma autoantibodies anti-GM-CSF, the most frequent form (90 % of all AP); secondary AP, mainly occurring as a consequence of haematological diseases, or following on from toxic inhalation or infections, and genetic AP, which affects almost exclusively children. AP diagnosis is suspected where chest CT-scan demonstrates interstitial lung disease with a crazy paving aspect; and confirmed by bronchoalveolar lavage, which has a milky appearance and contains periodic acid Schiff positive proteinaceous alveolar deposits. The use of surgical lung biopsy to confirm AP is less frequent nowadays. In this context, positive antibodies against GM-CSF indicates an auto-immune etiology of the AP. Concerning management, whole lung lavage is the gold standard therapy. In refractory AP, new treatments are available such as subcutaneous or inhaled GM-CSF supplementation, or rituximab infusions. The clinical course is unpredictable. Spontaneous improvement or even cure can occur, and the 5-year actuarial survival is 95 %. The most frequent complications are infectious etiology.
La protéinose alvéolaire pulmonaire (PAP) est une maladie rare caractérisée par l’accumulation alvéolaire de composants du surfactant qui gêne les échanges gazeux. Les PAP sont séparées en trois groupes : les PAP auto-immunes caractérisées par la présence d’anticorps sériques anti-GM-CSF qui sont les plus fréquentes ; les PAP secondaires à une maladie sous-jacente, le plus souvent hématologique, mais aussi à l’inhalation de toxiques et à des infections ; enfin, les PAP d’origine génétique. Le diagnostic de PAP est évoqué sur le scanner thoracique avec une pneumopathie infiltrante diffuse ayant un aspect classique de crazy paving, puis confirmé par l’aspect laiteux du lavage bronchoalvéolaire, et la présence de matériel lipoprotéinacé PAS positif. La confirmation du diagnostic de PAP par biopsie pulmonaire chirurgicale est désormais rarement nécessaire. La positivité des anticorps sériques anti-GM-CSF signe le caractère auto-immun de la maladie. Le traitement de référence des PAP auto-immunes est le « grand lavage pulmonaire thérapeutique ». En cas de maladie réfractaire, d’autres traitements sont disponibles, tels que le GM-CSF en injection sous-cutanée ou en aérosol et le rituximab. L’évolution de la maladie est imprévisible. Une évolution spontanément favorable ou même une guérison spontanée peuvent survenir et la survie actuarielle à 5 ans est de 95 %. Les principales complications sont infectieuses.
ISSN: 0761-8425

hal-01085907
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01085907
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01085907/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01085907/file/Prot%C3%A9inose%20alv%C3%A9olaire%20pulmonaire_accepted.pdf
DOI : 10.1016/j.rmr.2014.08.009

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Fish mucus has important biological and ecologicalroles such as defense against fish pathogens andchemical mediation among several species. A non-targetedliquid chromatography–mass spectrometry metabolomicapproach was developed to study gill mucus of eight butterflyfishspecies in Moorea (French Polynesia), and theinfluence of several fish traits (geographic site and reefhabitat, species taxonomy, phylogeny, diet and parasitismlevels) on the metabolic variability was investigated. Abiphasic extraction yielding two fractions (polar and apolar)was used. Fish diet (obligate corallivorous, facultativecorallivorous or omnivorous) arose as the main driver ofthe metabolic differences in the gill mucus in both fractions,accounting for 23% of the observed metabolic variabilityin the apolar fraction and 13% in the polar fraction.A partial least squares discriminant analysis allowed us toidentify the metabolites (variable important in projection,VIP) driving the differences between fish with differentdiets (obligate corallivores, facultative corallivores andomnivorous). Using accurate mass data and fragmentationdata, we identified some of these VIP as glycerophosphocholines,ceramides and fatty acids. Level of monogeneangill parasites was the second most important factor shapingthe gill mucus metabolome, and it explained 10% of themetabolic variability in the polar fraction and 5% in theapolar fraction. A multiple regression tree revealed that themetabolic variability due to parasitism in the polar fractionwas mainly due to differences between non-parasitized andparasitized fish. Phylogeny and butterflyfish species werefactors contributing significantly to the metabolic variabilityof the apolar fraction (10 and 3%, respectively) buthad a less pronounced effect in the polar fraction. Finally,geographic site and reef habitat of butterflyfish species didnot influence the gill mucus metabolome of butterflyfishes.
ISSN: 0722-4028

hal-01563312
https://hal-univ-perp.archives-ouvertes.fr/hal-01563312
DOI : 10.1007/s00338-017-1554-0

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We discuss mantle structure and dynamics under the Gibraltar arc. For that region, a large variety of geodynamic models has been proposed, and there was, up to recently, no consensus on which of these models is the best one to describe the geodynamic situation of the region. The key to distinguishing the different models probably lies in the upper mantle, and we propose two specially adapted seismological techniques that help to distinguish each of the two models that are more frequently invoked. These are, on one hand, the subduction-rollback (SR) model, and on the other, continental delamination or convective removal (CDCR). The first technique that we use is based on observations of dispersed P-wavetrains that are expected for certain ray directions. Observations made on the Gibraltar arc suggest the presence of subducted oceanic lithosphere under the Alboran Sea. The second technique is based on shear-wave splitting of SKS phases, and it allows us to look for the radially-oriented flow that must be present in the mantle beneath the Alboran Sea, for a CDCR mechanism. There are however no indications of any radial flow up to this point. Both approaches therefore suggest that subduction-rollback is the best model to explain the complex geodynamic situation under the region.
ISSN: 0040-1951

hal-01388041
http://hal.univ-reunion.fr/hal-01388041
http://hal.univ-reunion.fr/hal-01388041/document
http://hal.univ-reunion.fr/hal-01388041/file/Bokelmann_Gibraltar_Tphy2011_hal.pdf
DOI : 10.1016/j.tecto.2010.08.004

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Growth hormone (GH) may stimulate water loss during exercise by activating sweating. This study investigated GH secretion and water loss during sequential cycling and running, taking postural changes into account. The two exercise segments had similar durations and were performed at the same relative intensity to determine their respective contributions to water loss and the plasma volume variation noted in such trials. Eight elite triathletes first performed an incremental cycle test to assess maximal oxygen consumption. Then, the triathletes performed one of two trials in randomized order: constant submaximal cycling followed by treadmill running (C 1 –R 2) or an inversed succession of running followed by cycling (R 1 –C 2). Each segment of both trials was performed for 20 minutes at ,75% of maximal oxygen consumption. The second trial, reversing the segment order of the first trial, took place two weeks later. During cycling, the triathletes used their own bicycles equipped with a profiled handlebar. Blood sampling (for GH concentrations, plasma viscosity and plasma volume variation) was conducted at rest and after each segment while water loss was estimated from the post-and pre-measures. GH increases were significantly lower in R 2 than C 2 (72.2650.1 vs. 164.06157 ng.ml 21 .min 21 , respectively; P,0.05). Water loss was significantly lower after C 1 –R 2 than R 1 –C 2 (11056163 and 12356153 ml, respectively; P,0.05). Plasma volume variation was significantly negative in C 1 and R 1 (26.1562.0 and 23.1665.0%, respectively; P,0.05), not significant in C 2 , and significantly positive for seven subjects in R 2 (4.0563.1%). We concluded that the lower GH increases in R 2 may have contributed to the smaller reduction in plasma volume by reducing sweating. Moreover, this lower GH response could be explained by the postural change during the transition from cycling to running. We recommend to pay particular attention to their hydration status during R 1 which could limit a potential dehydration during C 2 .
ISSN: 1932-6203

hal-01136734
https://hal.univ-antilles.fr/hal-01136734
https://hal.univ-antilles.fr/hal-01136734/document
https://hal.univ-antilles.fr/hal-01136734/file/Galy%20et%20al.%20-%202014%20-%20Sequential%20exercise%20in%20triathletes%20Variations%20in%20GH%20and%20water%20loss.pdf
DOI : 10.1371/journal.pone.0096145

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Orogenic lherzolites exhibit a specific (although reproducible) platinum-group element signature characterized by slight positive deviations of Pd/Ir, Rh/Ir and Ru/Ir ratios from the canonical chondritic model. Such a signature was alternatively considered to be a compositional feature of the primitive upper mantle or resulting from sulfide melt addition by refertilisation reactions in the continental lithosphere. To shed additional light on this conundrum, the distribution of PGE in FON B 93, an unserpentinized, fertile (3.24% Al2O3) orogenic lherzolite (French Pyrenees) used as in-house standard by our group, has been studied to different scales, from the bulk rock to trace minerals. In addition to new ICPMS analyses after separation into Nis and Te coprecipitation, its whole-rock PGE concentrations were redetermined by three different laboratories using very precise ID-ICP-MS methods after digestion of the sample in Carius tube at T=250 degrees C and 320 degrees C or in high-pressure asher (HPA-S). The four methods produce reproducible Ru, Rh and Pd contents (7.1 +/- 0.18 ppb; 1.43 +/- 0.05 ppb; 7.1 +/- 0.30 ppb) whereas the non-ID NiS-fire assay method underestimates the Os and Ir concentrations by c.a. 10 and 15% compared to ID-ICP-MS analyses (4.40 +/- 0.07 and 4.00 +/- 0.17 ppb, respectively). Platinum was the most difficult to analyse. If performed on powder aliquots smaller than 3 g, the ID-ICP-MS analyses generate strong nugget effects while the non-ID NiS-fire assay method yields statistically lower (but highly reproducible) Pt concentrations (6.92 +/- 0.26 ppb). These features reflect the strong partitioning of Pt into trace phases that SEM and laser ablation-ICP-MS analyses on thin sections identify as both high-temperature Pt-Ir-Os alloys and Pt-(Pd) tellurides of likely subsolidus origin; ten to fifteen grains ranging in maximum dimension from a few micrometres to a few hundreds of nanometers, were identified by standard polished thin section. LA-ICP-MS data on base metal sulfides (25 grains analysed), coupled with the whole-rock S concentration (277 +/- 10 ppm) and modal composition of the BMS (90% pentlandite+accessory pyrite and secondary pyrrhotite + 10% chalcopyrite) allowed the contribution of the BMS phase to the PGE budget of FON B 93 to be estimated. Except Pt that exhibits a 95% deficit in the BMS phase, the PGE concentrations measured by ID-ICP-MS can be balanced by BMS while Al-spinel is a negligible contributor, accounting for less than 0.5% of the Ru budget. The occurrence of Pt in trace phases may bias the whole-rock Pt concentrations because 1) mechanical collection of Pt-rich trace phases remains problematic with the Nis button, and 2) Pt-Ir-Os alloys may be prone to digestion problems in conventional Carius tube procedures. Since they could be stable at mantle depth, such refractory alloys that contain Os and Ir may also have enhanced the heavy PGEs/light PGEs fractionation. Our observations likely pertain to orogenic lherzolites as a whole because BMS assemblages in these mantle rocks record evolution at low sulfur fugacity, which prevents Pt-Ir-Os alloy from entering the Mss in the mantle; moreover, at subsolidus temperature, pentlandite, the major BMS, cannot accommodate 0 valence state Pt.
ISSN: 0009-2541

hal-00411486
https://hal.archives-ouvertes.fr/hal-00411486
DOI : 10.1016/j.chemgeo.2007.06.030

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Absolute earthquake hypocenter locations have been determined in the area offshore eastern Taiwan, at the Southernmost Ryukyu subduction zone. Location process is run within a 3D velocity model by combining the Taiwanese and neighboring Japanese networks and using the 3D MAXI technique. The study focuses on the most active seismic cluster in the Taiwan region that occurs in the forearc domain offshore eastern Taiwan. Earthquakes distribute mainly along 2 active planes. The first one aligns along the subduction interface and the second one, shallower affects the overriding margin. Focal mechanisms within the shallow group indicate that nodal planes are either compatible with high-angle back-thrusts or low-angle thrusts. The active seismic deformation exclusively indicates reverse faulting revealing that the forearc basement undergoes trench-perpendicular strong compression. By integrating the seismological image into the regional context, we favor the hypothesis in which the dense seismicity occurring offshore marks the activity of en-échelon high-angle reverse faults accommodating the uplift of a broken piece of Ryukyu Arc basement, called Hoping Basement Rise. The uplift is inferred to be caused by the subduction of an oceanic relief, either exotic block, seamount or oceanic crust sliver. Our favored solution satisfies the narrowness of epicenter's cluster along the Hoping Canyon, and the observation of high-angle active faults on seismic lines crossing the area. Furthermore, this solution is compatible with the active uplift of the Hoping Rise demonstrated from morphological and sedimentological data. We do not exclude the branching of the high-angle reverse faults system onto a splay fault connected with the subduction interface but further investigations are needed to map precisely the 3D distribution of active faults that break the margin.
ISSN: 0040-1951

hal-00407726
https://hal.archives-ouvertes.fr/hal-00407726
DOI : 10.1016/j.tecto.2007.11.018

Éditeur(s) : HAL CCSD
Résumé : Due to their phylogenetic position outside from Bilateria, cnidarians and ctenophores are key phyla to understanding the origin and early evolution of molecular mechanisms, cell types, or body plan features at the level of Metazoa. Unlike other non-bilaterian phyla (sponges and placozoans), they possess neurons and muscle cells. The first part of my work relates to the problem of the origin of the metazoan nervous system. Recent studies have suggested a dual origin for nerve cells, with ctenophore neurons having emerged independently from those of cnidarians and bilaterians. This hypothesis relies on phylogenomic analyses supporting ctenophores as sister-group to all other metazoans, and on the purported absence in ctenophores of almost all well-known neuro-transmission systems, including the cholinergic system. Refuting this claim, I present substantial evidence in favour of acetylcholine (Ach) being used in the ctenophore Pleurobrachia pileus as an extra-cellular messenger, including within the nervous system. This conclusion arises from the conjunction of multiple approaches at the molecular scale (orthology analyses, Ach immuno-localisation, gene in situ hybridisation), at the cellular scale (calcium imaging on muscle cells exposed to Ach) and at the organism scale (pharmacological treatments with an Ach analogue and Ach antagonists). In the second part of my thesis, I address the conservation of molecular mechanisms involved in the control of cellular proliferation. Notably, the Hippo pathway is known for its role in bilaterians in the negative control of cellular proliferation. I show that components of this pathway are conserved in Pleurobrachia pileus and in Clytia hemisphaerica and that the nuclear vs. cytoplasmic localisation of the transcriptional co-factor Yorkie is correlated to the extent of proliferation within C. hemisphaerica tissues. Finally, RNAseq differential gene expression analyses along a cellular conveyor belt of the C. hemisphaerica medusa suggests a tendency for conservation of function among a set of genes whose mammalian orthologues have documented roles in the arrest of cellular proliferation.
Les Cnidaires et les Cténaires sont deux embranchements extérieurs aux Bilatériens qui, de par leur position phylogénétique, constituent des modèles d'étude cruciaux pour comprendre l'origine et l'évolution de mécanismes moléculaires ou encore de types cellulaires à grande échelle chez les Métazoaires. Ils sont les deux seuls embranchements non-Bilatériens à posséder des cellules nerveuses ainsi que des cellules musculaires. La première partie de mon travail de thèse s'inscrit dans le contexte de la compréhension de l'origine du système nerveux des Métazoaires. Des études récentes suggèrent une origine double du système nerveux ; ainsi celui des Cténaires aurait été acquis de manière convergente par rapport à celui des Cnidaires et des Bilatériens. Cela repose sur des données récentes de phylogénomique proposant les Cténaires en tant que groupe-frère de tous les autres Métazoaires et sur l'absence supposée chez les Cténaires de quasiment tous les systèmes de neurotransmission connus y compris le système cholinergique. A l'encontre de ces hypothèses, j'ai pu mettre en évidence l'existence d'un système cholinergique chez le Cténaire Pleurobrachia pileus ainsi que son étroite association avec le système nerveux. Cette conclusion repose sur une multiplicité d'approches à l'échelle moléculaire (analyses d'orthologie, immunolocalisation, hybridations in situ), cellulaire (imagerie calcique) et de l'organisme (approche pharmacologique). Dans la seconde partie de ma thèse, j'aborde la question de la conservation des mécanismes moléculaires impliqués dans le contrôle de la prolifération cellulaire à l'échelle des Métazoaires. J'ai pu mettre en évidence la conservation des acteurs.
https://tel.archives-ouvertes.fr/tel-01633223

NNT : 2015PA066629
tel-01633223
https://tel.archives-ouvertes.fr/tel-01633223
https://tel.archives-ouvertes.fr/tel-01633223v2/document
https://tel.archives-ouvertes.fr/tel-01633223/file/2015PA066629.pdf

Éditeur(s) : HAL CCSD MDPI
Résumé : International audience
The decline in children's Blood Lead Levels (BLL) raises questions about the ability of current lead poisoning screening criteria to identify those children most exposed. The objectives of the study were to evaluate the performance of current screening criteria in identifying children with blood lead levels higher than 50 µg/L in France, and to propose new criteria. Data from a national French survey, conducted among 3831 children aged 6 months to 6 years in 2008-2009 were used. The sensitivity and specificity of the current criteria in predicting blood lead levels higher than or equal to 50 µg/L were evaluated. Two predictive models of BLL above 44 µg/L (for lack of sufficient sample size at 50 µg/L) were built: the first using current criteria, and the second using newly identified risk factors. For each model, performance was studied by calculating the area under the ROC (Receiver Operating Characteristic) curve. The sensitivity of current criteria for detecting BLL higher than or equal to 50 µg/L was 0.51 (0.26; 0.75) and specificity was 0.66 (0.62; 0.70). The new model included the following criteria: foreign child newly arrived in France, mother born abroad, consumption of tap water in the presence of lead pipes, pre-1949 housing, period of construction of housing unknown, presence of peeling paint, parental smoking at home, occupancy rates for housing and child's address in a cadastral municipality or census block comprising more than 6% of housing that is potentially unfit and built pre-1949. The area under the ROC curve was 0.86 for the new model, versus 0.76 for the current one. The lead poisoning screening criteria should be updated. The risk of industrial, occupational and hobby-related exposure could not be assessed in this study, but should be kept as screening criteria
ISSN: 1660-4601

hal-01239804
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01239804
DOI : 10.3390/ijerph121214989
PUBMED : 26633457

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : International audience
The diagnosis of some infectious diseases is sometimes difficult to make and new diagnostic tools have been regularly assessed to that end. 18fluoro-deoxyglucose ((18)FDG) positron-emission tomography (PET) coupled with computed tomography (CT) is one of these new procedures. It has been evaluated for numerous infectious diseases with uneven results. A literature review allowed drawing some conclusions. First, (18)FDG-PET/CT is not currently a first-line procedure for infectious diseases. Second, it has proved useful for the evaluation of patients presenting with fever of unknown origin (FUO). Its negative predictive value is 100%: the symptoms of patients experiencing FUO with negative first-line investigations and a negative (18)FDG-PET/CT will almost always spontaneously disappear. Third, (18)FDG-PET/CT also seems to be contributive for the diagnosis of vascular prosthesis infections or osteomyelitis. Fourth, it has promising results for patients presenting with infective endocarditis, especially for secondary infectious foci, or for patients presenting with suspected infection of pacemakers or implanted defibrillator; but results are still preliminary and must be confirmed. Finally(18)FDG-PET/CT cannot be recommended yet for other infectious diseases due to lack of published data.
ISSN: 0399-077X

hal-01064982
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01064982
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01064982/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01064982/file/Contributionsur 18Fluoro_deoxyglucose_PETCT_accepted.pdf
DOI : 10.1016/j.medmal.2014.04.007

Éditeur(s) : HAL CCSD
Résumé : International audience
Sciences curriculum, official instructions and scholar books are the same for all French pupils. Some official scientific aims of secondary schools (11–18 years old) like seasons and moon observation may not fit with nature observation in French West Indies. To overcome this obstacle and improve sciences education in French West Indies, a better understanding of representation of students seems necessary. A questionnaire was fulfilled by 124 first year students from Guadeloupe. European seasons descriptions are significantly more precise than Caribbean ones in year period as in climatic characteristics (temperature and humidity). More than 75% of answers do not take in account the relationship between moon orientation and latitude. The majority of students seem to perceive the moon as represented in the models of education or cultural product from temperate areas and not as they see it. Here we seem to face a kind of inverted obstacle in the epistemological sense. It is not the naive observation of nature that makes it more difficult to understand scientific concepts but universal selection of content (examples, models, order of ideas) that explains science taught imperfectly observable in specific educational setting.
ESERA 2011 Science Learning and Citizenship
Lyon, France

Droits : info:eu-repo/semantics/OpenAccess
hal-01539485
https://hal.univ-antilles.fr/hal-01539485
https://hal.univ-antilles.fr/hal-01539485/document
https://hal.univ-antilles.fr/hal-01539485/file/ESERA2011.pdf

Éditeur(s) : HAL CCSD
Résumé : In this thesis, we propose a method to solve some Cauchy problems with irregular or characteristic data by using the recent theories of generalized functions. We study a regular Cauchy problem and a regular Goursat problem in the first part with data on a monotonic curve. The second part is devoted to the setting up of an algebra adapted to the generalized Cauchy problem. In the third part, we give a meaning to a generalized Cauchy problem and we show that the problem admits a unique solution. We study a generalized Goursat problem in the same way. In the fourth part, we approach a characteristic Cauchy problem by a family of non-characteristic ones. The family of solutions is a representative of a generalized function we consider as the generalized solution of the problem in an appropriate algebra. We give a meaning to the characteristic Cauchy problem with irregular data by replacing it by a family of non-characteristic problems in an appropriate biparametric algebra. The first parameter permits to replace the given problem by a non-characteristic one, whereas the second parameter makes it regular. The family of solutions is a representative of a generalized function considered as the solution of the problem.
Dans cette thèse nous proposons une méthode pour résoudre certains problèmes de Cauchy à données irrégulières ou caractéristiques en utilisant les récentes théories des fonctions généralisées. Nous étudions dans la première partie un problème de Cauchy et un problème de Goursat réguliers avec des données sur une courbe monotone. La deuxième partie est consacrée à la mise en place d'une algèbre adaptée à la résolution du problème de Cauchy généralisé. Dans la troisième partie nous donnons un sens à un problème de Cauchy généralisé et nous montrons qu'il admet une unique solution. Nous étudions de même un problème de Goursat généralisé. Dans la quatrième partie nous approchons un problème de Cauchy caractéristique par une famille de problèmes non caractéristiques. La famille de solutions est un représentant d'une fonction généralisée que nous considérons comme la solution généralisée du problème dans une algèbre appropriée. Nous donnons un sens au problème de Cauchy caractéristique dans le cas de données irrégulières en le remplaçant par une famille de problèmes non caractéristiques dans une algèbre convenable dépendant de deux paramètres. Le premier paramètre permet de se ramener à un problème non caractéristique que le second rend régulier. La famille de solutions est un représentant d'une fonction généralisée que nous considérons comme la solution du problème.
https://tel.archives-ouvertes.fr/tel-00012098

Droits : info:eu-repo/semantics/OpenAccess
tel-00012098
https://tel.archives-ouvertes.fr/tel-00012098
https://tel.archives-ouvertes.fr/tel-00012098v2/document
https://tel.archives-ouvertes.fr/tel-00012098/file/These-Devoue-29-12-2006.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
The SOX8 and SOX9 transcription factors are involved in, among others, sex differentiation, male gonad development and adult maintenance of spermatogenesis. Sox8(-/-) mice lacking Sox9 in Sertoli cells fail to form testis cords and cannot establish spermatogenesis. Although genetic and histological data show an important role for these transcription factors in regulating spermatogenesis, it is not clear which genes depend upon them at a genome-wide level. To identify transcripts that respond to the absence of Sox8 in all cells and Sox9 in Sertoli cells we measured mRNA concentrations in testicular samples from mice at 0, 6 and 18 days post-partum. In total, 621 and 629 transcripts were found at decreased or increased levels, respectively, at different time points in the mutant as compared to the control samples. These mRNAs were categorized as preferentially expressed in Sertoli cells or germ cells using data obtained with male and female gonad samples and enriched testicular cell populations. Five candidate genes were validated at the protein level. Furthermore, we identified putative direct SOX8 and SOX9 target genes by integrating predicted SOX-binding sites present in potential regulatory regions upstream of the transcription start site. Finally, we used protein network data to gain insight into the effects on regulatory interactions that occur when Sox8 and Sox9 are absent in developing Sertoli cells. The integration of testicular samples with enriched Sertoli cells, germ cells and female gonads enabled us to broadly distinguish transcripts directly affected in Sertoli cells from others that respond to secondary events in testicular cell types. Thus, combined RNA profiling signals, motif predictions and network data identified putative SOX8/SOX9 target genes in Sertoli cells and yielded insight into regulatory interactions that depend upon these transcription factors. In addition, our results will facilitate the interpretation of genome-wide in vivo SOX8 and SOX9 DNA binding data.
Andrology

hal-00877013
https://hal.archives-ouvertes.fr/hal-00877013
DOI : 10.1111/j.2047-2927.2012.00049.x
PUBMED : 23315995