The baryonic content and Tully-Fisher relation at z~0.6

[abr.] Using the multi-integral-field spectrograph GIRAFFE at VLT, we previsouly derived the stellar-mass Tully-Fisher Relation (smTFR) at z~0.6, and found that the distant relation is systematically offset by roughly a factor of two toward lower masses. We extend the study of the evolution of the TFR by establishing the first distant baryonic TFR. To derive gas masses in distant galaxies, we estimate a gas radius and invert the Schmidt-Kennicutt law between star formation rate and gas surface densities. We find that gas extends farther out than the UV light from young stars, a median of ~30%. We present the first baryonic TFR (bTFR) ever established at intermediate redshift and show that, within an uncertainty of +/-0.08 dex, the zeropoint of the bTFR does not appear to evolve between z~0.6 and z=0. The absence of evolution in the bTFR over the past 6 Gyr implies that no external gas accretion is required for distant rotating disks to sustain star formation until z=0 and convert most of their gas into stars. Finally, we confirm that the larger scatter found in the distant smTFR, and hence in the bTFR, is caused entirely by major mergers. This scatter results from a transfer of energy from bulk motions in the progenitors, to random motions in the remnants, generated by shocks during the merging. Shocks occurring during these events naturally explain the large extent of ionized gas found out to the UV radius in z~0.6 galaxies. All the results presented in this paper support the ``spiral rebuilding scenario'' of Hammer and collaborators, i.e., that a large fraction of local spiral disks have been reprocessed during major mergers in the past 8 Gyr.Comment: Accepted for publication in A&A, v3 addressing comments from the refere

The relation between Lyman-alpha absorbers and gas--rich galaxies in the local universe

We use high-resolution hydrodynamical simulations to investigate the spatial correlation between weak (N(HI) <10^{15} cm^{-2}) Ly-alpha absorbers and gas-rich galaxies in the local universe. We confirm that Ly-alpha absorbers are preferentially expected near gas-rich galaxies and that the degree of correlation increases with the column density of the absorber. The real-space galaxy auto-correlation is stronger than the cross-correlation (correlation lengths r_{0,gg}=3.1 \pm 0.1 Mpc/h and r_{0,ag}=1.4 \pm 0.1 Mpc/h, respectively), in contrast with the recent results of Ryan-Weber (2006, RW06), and the auto-correlation of absorbers is very weak. These results are robust to the presence of strong galactic winds in the hydrodynamical simulations. In redshift-space a further mismatch arises since at small separations the distortion pattern of the simulated galaxy-absorber cross-correlation function is different from the one measured by RW06. However, when sampling the intergalactic medium along a limited number of lines-of-sight, as in the real data, uncertainties in the cross correlation estimates are large enough to account for these discrepancies. Our analysis suggests that the statistical significance of difference between the cross-correlation and auto-correlation signal in current datasets is ~ 1-sigma only.Comment: 11+ pages, 9 figures. MNRAS in pres

Études structurales de polymères thermochromes et affinitéchromes

Les polymères conjugués organiques ont reçu beaucoup d'attention depuis les 25 dernières années à cause de leur fort potentiel pour des applications en microélectronique, électrooptique et biophotonique. Cependant, les propriétés physiques des polymères conjugués semi-conducteurs dépendent de façon critique de leur structure moléculaire, leur dopage et leur morphologie. Il est donc d'un grand intérêt d'étudier les relations structures / propriétés dans ces matériaux. Parmi ces matériaux, certains polymères conjugués ont aussi la propriété de changer de couleur selon le stimulus impliqué et sont alors appelés thermochromes, solvatochromes ou affinitéchromes. Ces polymères peuvent détecter et transférer de l'information physique ou chimique en un signal optique. Selon la structure du polymère, cette transition a été expliquée par un changement conformationnel du squelette et / ou une variation des interactions interchaînes n-n [i.e. Pi-Pi] Ce travail avait pour objectif d'acquérir une meilleure compréhension des phénomènes conformationnels impliqués lors de la transition chromique. Pour cela, nous avons étudié différents polymères modèles, tels les polythiophènes et les polyphénylèneéthynylènes et essayé d'apporter de nouvelles preuves de l'implication majeure du squelette conjugué dans le cas des polythiophènes alors que, concernant les polyphénylèneéthynylènes, une contribution majoritairement interchaîne serait à l'origine du phénomène de chromisme. En particulier, la transition chromique du poly(3-(2-méthyl-l-butoxy)-4- méthylthiophene) a été étudiée à l'état solide. Des changements importants ont été observés en absorption UV-visible, diffraction de rayons X et spectroscopies infrarouge et Raman

Prise en charge des syndromes démentiels des personnes âgées par le médecin généraliste

BREST-BU Médecine-Odontologie (290192102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Exercise-Induced Vasculitis: A Review with Illustrated Cases

International audienceAlthough exercise-induced vasculitis (EIV) is usually misdiagnosed, it is not uncommon. Occurring mostly after prolonged exercise, especially in hot weather, EIV is an isolated cutaneous vasculitis with stereotypical presentation. This article reviews the clinical characteristics, treatments, and outcomes of EIV based on the published literature. We report 99 patients who developed EIV after walking, dancing, swimming, or hiking especially during hot weather, including the records of 16 patients with EIV treated at our hospital from 2007 to 2015. Erythematous or purpuric plaques arise on the lower legs, without the involvement of compression socks or stockings. Symptoms include itch, pain, and a burning sensation. EIV is an isolated cutaneous vasculitis. Lesions resolve spontaneously after 10 days. When triggering conditions persist, relapses are frequent (77.5 %). Histopathology demonstrates leukocytoclastic vasculitis in 95 % of cases with C3 or immunoglobulin M deposits in 88 and 46 % of cases, respectively. Blood investigations are negative. EIV appears to be a consequence of venous stasis induced by an acute failure of the muscle pump of the calf and thermoregulation decompensation. Both appear after prolonged and unusual exercise in hot weather. Treatment is not codified; topical corticosteroids may reduce symptoms and wearing light clothes might limit lesion occurrence