Institution
University of Rennes
Education•Rennes, France•
About: University of Rennes is a education organization based out in Rennes, France. It is known for research contribution in the topics: Population & Crystal structure. The organization has 18404 authors who have published 40374 publications receiving 995327 citations.
Topics: Population, Crystal structure, Ruthenium, Catalysis, Antenna (radio)
Papers published on a yearly basis
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TL;DR: The first evidence that DEHP and MEHP can inhibit testosterone production in the adult human testis is provided, consistent with recent epidemiological findings of an inverse correlation between exposure to MEHP and testosterone concentrations.
Abstract: BACKGROUND: Phthalic acid esters are widely used in the manufacture of plastics. Numerous studies have shown that these phthalates impair testicular testosterone production in the rat. However, the scarce and contradictory data concerning humans have cast doubt over whether these compounds are also anti-androgenic in man. We therefore investigated the direct effects of di-(2-ethylhexyl) phthalate (DEHP) and mono-(2-ethylhexyl) phthalate (MEHP) on organo-cultured adult human testis and a human cell line. METHODS: Adult human testis explants or NCI-H295R adrenocortical human cells were cultured with DEHP or MEHP. The effects of ketoconazole, used as a reference molecule, were also assessed. RESULTS: In both models, DEHP and MEHP significantly inhibited testosterone production. The effects of both phthalates appeared to be specific for steroidogenesis, as INSL3 production by Leydig cells was not altered. Furthermore, the phthalates of interest had no effect on inhibin B production by Sertoli cells or on germ cell apoptosis. As only a small fraction of the phthalates added was found in the testis explants, and as these compounds were found to be metabolized, we estimate that the anti-androgenic effects observed occurred at concentrations of phthalates that are of the same order of magnitude as exposures reported in the literature for men. CONCLUSIONS: We provide the first evidence that DEHP and MEHP can inhibit testosterone production in the adult human testis. This is consistent with recent epidemiological findings of an inverse correlation between exposure to MEHP and testosterone concentrations.
169 citations
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TL;DR: In this article, the effect of landscape on dispersal was investigated in a forest-dwelling species, the American marten (Martes americana) using the genetic model of isolation by distance (IBD).
Abstract: Empirical studies of landscape connectivity are limited by the difficulty of directly measuring animal movement. ‘Indirect’ approaches involving genetic analyses provide a complementary tool to ‘direct’ methods such as capture–recapture or radio-tracking. Here the effect of landscape on dispersal was investigated in a forest-dwelling species, the American marten (Martes americana) using the genetic model of isolation by distance (IBD). This model assumes isotropic dispersal in a homogeneous environment and is characterized by increasing genetic differentiation among individuals separated by increasing geographic distances. The effect of landscape features on this genetic pattern was used to test for a departure from spatially homogeneous dispersal. This study was conducted on two populations in homogeneous vs. heterogeneous habitat in a harvested boreal forest in Ontario (Canada). A pattern of IBD was evidenced in the homogeneous landscape whereas no such pattern was found in the near-by harvested forest. To test whether landscape structure may be accountable for this difference, we used effective distances that take into account the effect of landscape features on marten movement instead of Euclidean distances in the model of isolation by distance. Effective distances computed using least-cost modeling were better correlated to genetic distances in both landscapes, thereby showing that the interaction between landscape features and dispersal in Martes americana may be detected through individual-based analyses of spatial genetic structure. However, the simplifying assumptions of genetic models and the low proportions in genetic differentiation explained by these models may limit their utility in quantifying the effect of landscape structure.
169 citations
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TL;DR: The results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo as discussed by the authors.
Abstract: We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave emission from any of the targeted sources but produce upper limits on the emission amplitude. We highlight the results from seven young pulsars with large spin-down luminosities. We reach within a factor of five of the canonical spin-down limit for all seven of these, whilst for the Crab and Vela pulsars we further surpass their spin-down limits. We present new or updated limits for 172 other pulsars (including both young and millisecond pulsars). Now that the detectors are undergoing major upgrades, and, for completeness, we bring together all of the most up-to-date results from all pulsars searched for during the operations of the first-generation LIGO, Virgo and GEO600 detectors. This gives a total of 195 pulsars including the most recent results described in this paper.
169 citations
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TL;DR: The migration of a suspended vesicle in an unbounded Poiseuille flow is investigated numerically in the low Reynolds number limit and the migration velocity is found to increase with the local capillary number, but reaches a plateau above a certain value of the capillaryNumber.
Abstract: The migration of a suspended vesicle in an unbounded Poiseuille flow is investigated numerically in the low Reynolds number limit. We consider the situation without viscosity contrast between the interior of the vesicle and the exterior. Using the boundary integral method we solve the corresponding hydrodynamic flow equations and track explicitly the vesicle dynamics in two dimensions. We find that the interplay between the nonlinear character of the Poiseuille flow and the vesicle deformation causes a cross-streamline migration of vesicles toward the center of the Poiseuille flow. This is in a marked contrast with a result [L. G. Leal, Annu. Rev. Fluid Mech. 12, 435 (1980)] according to which the droplet moves away from the center (provided there is no viscosity contrast between the internal and the external fluids). The migration velocity is found to increase with the local capillary number (defined by the time scale of the vesicle relaxation toward its equilibrium shape times the local shear rate), but reaches a plateau above a certain value of the capillary number. This plateau value increases with the curvature of the parabolic flow profile. We present scaling laws for the migration velocity.
169 citations
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Yale University1, Institute for Geosciences and Natural Resources2, University of Potsdam3, University of California, San Diego4, National Oceanography Centre, Southampton5, Texas A&M University6, University of Zaragoza7, University of Rennes8, University College London9, Pennsylvania State University10, Aix-Marseille University11, University of Minnesota12, University of Münster13, University of Bremen14, Heidelberg University15, Leipzig University16, University of Edinburgh17, University of Utah18, Max Planck Society19, Waseda University20, Baylor University21, University of Hawaii22, ConocoPhillips23, Institute of Arctic and Alpine Research24, Open University25, Harvard University26, Geological Survey of Denmark and Greenland27, Massachusetts Institute of Technology28, Wesleyan University29, University of California, Santa Cruz30
TL;DR: Carbon cycle modeling and paleotemperature records are used to constrain the timing of volcanogenic outgassing and found support for major out gassing beginning and ending distinctly before the impact, with only the impact coinciding with mass extinction and biologically amplified carbon cycle change.
Abstract: The cause of the end-Cretaceous mass extinction is vigorously debated, owing to the occurrence of a very large bolide impact and flood basalt volcanism near the boundary. Disentangling their relative importance is complicated by uncertainty regarding kill mechanisms and the relative timing of volcanogenic outgassing, impact, and extinction. We used carbon cycle modeling and paleotemperature records to constrain the timing of volcanogenic outgassing. We found support for major outgassing beginning and ending distinctly before the impact, with only the impact coinciding with mass extinction and biologically amplified carbon cycle change. Our models show that these extinction-related carbon cycle changes would have allowed the ocean to absorb massive amounts of carbon dioxide, thus limiting the global warming otherwise expected from postextinction volcanism.
169 citations
Authors
Showing all 18470 results
Name | H-index | Papers | Citations |
---|---|---|---|
Philippe Froguel | 166 | 820 | 118816 |
Bart Staels | 152 | 824 | 86638 |
Yi Yang | 143 | 2456 | 92268 |
Geoffrey Burnstock | 141 | 1488 | 99525 |
Shahrokh F. Shariat | 118 | 1637 | 58900 |
Lutz Ackermann | 116 | 669 | 45066 |
Douglas R. MacFarlane | 110 | 864 | 54236 |
Elliott H. Lieb | 107 | 512 | 57920 |
Fu-Yuan Wu | 107 | 367 | 42039 |
Didier Sornette | 104 | 1295 | 44157 |
Stefan Hild | 103 | 452 | 68228 |
Pierre I. Karakiewicz | 101 | 1207 | 40072 |
Philippe Dubois | 101 | 1098 | 48086 |
François Bondu | 100 | 440 | 69284 |
Jean-Michel Savéant | 98 | 517 | 33518 |