The Evolution of the Baryon Distribution in the Universe from Cosmological Simulations

The evolution of the baryon distribution in different phases, derived from cosmological simulations, are here reported. These computations indicate that presently most of baryons are in a warm-hot intergalactic (WHIM) medium (about 43%) while at z = 2.5 most of baryons constitute the diffuse medium (about 74%). Stars and the cold gas in galaxies represent only 14% of the baryons at z = 0. For z < 4 about a half of the metals are locked into stars while the fraction present in the WHIM and in the diffuse medium increases with a decreasing redshift. In the redshift range 0 < z < 2.5, the amount of metals in the WHIM increases from 4% to 22% while in the diffuse medium it increases from 0.6% to 4%. This enrichment process is due essentially to a turbulent diffusion mechanism associated to mass motions driven by supernova explosions. At z = 0, simulated blue (late type) galaxies show a correlation of the oxygen abundance present in the cold gas with the luminosity of the considered galaxy that agrees quite well with data derived from HII regions.Comment: 12 pages, 6 figures, to be published in IJMP

Ma thèse en 9 173 caractères

National audienceCertains archéologues ont trouvé leur vocation grâce à Indiana Jones. Pour moi, c'est l'Antiquité égyptienne qui a allumé les premières étincelles et le feu a vraiment pris en fouillant de l'habitat médiéval. J'avais 15 ans. J'ai ensuite continué à me former sur des sites archéologiques très variés, fait une licence d'histoire puis deux masters en archéologie (un «recherche», l'autre «professionnel»), et enfin un doctorat. Très bien me direz-vous, mais pourquoi avoir choisi comme sujet de thèse Les monuments funéraires du diocèse de Limoges (XIe-XIIIe siècles) ? Pour une raison très simple : répondre à une demande du Service régional de l'archéologie. J'étais alors en master

Evolution of Supermassive Black Holes from Cosmological Simulations

The correlations between the mass of supermassive black holes and properties of their host galaxies are investigated through cosmological simulations. Black holes grow from seeds of 100 solar masses inserted into density peaks present in the redshift range 12-15. Seeds grow essentially by accreting matter from a nuclear disk and also by coalescences resulting from merger episodes. At z=0, our simulations reproduce the black hole mass function and the correlations of the black hole mass both with stellar velocity dispersion and host dark halo mass. Moreover, the evolution of the black hole mass density derived from the present simulations agrees with that derived from the bolometric luminosity function of quasars, indicating that the average accretion history of seeds is adequately reproduced . However, our simulations are unable to form black holes with masses above $10^9 M_{\odot}$ at $z\sim 6$, whose existence is inferred from the bright quasars detected by the Sloan survey in this redshift range.Comment: Talk given at the International Workshop on Astronomy and Relativistic Astrophysics (IWARA 2009), Maresias, Brazil. to be published in the International Journal of Modern Physics

Novel modeling strategy for a BCI set-up applied in an automotive application: an industrial way to use EM simulation tools to help Hardware and ASIC designers to improve their designs for immunity tests

Electronics suppliers of automotive industry use BCI (Bulk Current Injection) measurements to qualify immunity robustness of their equipment whereas electronics components manufacturers use DPI (Direct Power Injection) to qualify immunity of their component. Due to harness resonances, levels obtained during a BCI test exceed standard DPI requirements imposed by automotive suppliers onto components' manufacturers. We propose to use BCI set-up modeling to calculate the equivalent DPI level obtained at the component level during equipment testing and to compare results with DPI measurements realized at IC level

Education choices and Degrees from 1985 to 2002

The education level of young French people rose considerably from 1985 to 1995, stabilising over the last two years. The number of graduates from higher education doubled in 1996 compared with 1985, and represented nearly 38% of a given age bracket in 2001. At the same time, starting in the late 1980s, more young people entered the general secondary school third and fourth years, went more often into upper school to follow a general or technological course and went on to obtain better baccalauréat pass rates. High percentages then studied in higher education with better higher education qualification pass rates. At the same time, vocational education recruited slightly fewer, albeit more highly educated young people and put a larger number through the baccalauréat. The increasingly high level of qualifications and lengthening of studies concerned more especially the last generations in the baby boom.Educational Attainment, School Leavers

Quasiconvex Constrained Multicriteria Continuous Location Problems: Structure of Nondominated Solution Sets

In this paper, we consider constrained multicriteria continuous location problems in two-dimensional spaces. In the literature, the continuous multicriteria location problem in two-dimensional spaces has received special attention in the last years, although only particular instances of convex functions have been considered. Our approach only requires the functions to be strictly quasiconvex and inf-compact. We obtain a geometrical description that provides a unified approach to handle multicriteria location models in two-dimensional spaces which has been implemented in MATHEMATIC

Coalescence Rate of Supermassive Black Hole Binaries Derived from Cosmological Simulations: Detection Rates for LISA and ET

The coalescence history of massive black holes has been derived from cosmological simulations, in which the evolution of those objects and that of the host galaxies are followed in a consistent way. The present study indicates that supermassive black holes having masses greater than $\sim 10^{9} M_{\odot}$ underwent up to 500 merger events along their history. The derived coalescence rate per comoving volume and per mass interval permitted to obtain an estimate of the expected detection rate distribution of gravitational wave signals ("ring-down") along frequencies accessible by the planned interferometers either in space (LISA) or in the ground (Einstein). For LISA, in its original configuration, a total detection rate of about $15 yr^{-1}$ is predicted for events having a signal-to-noise ratio equal to 10, expected to occur mainly in the frequency range $4-9 mHz$. For the Einstein gravitational wave telescope, one event each 14 months down to one event each 4 years is expected with a signal-to-noise ratio of 5, occurring mainly in the frequency interval $10-20 Hz$. The detection of these gravitational signals and their distribution in frequency would be in the future an important tool able to discriminate among different scenarios explaining the origin of supermassive black holes.Comment: 18 pages, 7 figures, to appear in the IJMP

Locomotor Inhibition in Adult Horses Faced to Stressors: A Single Postpartum Experience May be Enough!

International audienceDespite the number of postpartum handling that a newborn experiences, few studies focus on their long-term consequences. In rats, regular long separations from the mother, during the early life, led to modifications of the locomotor activity when the animal is confronted to a stressor. In horses, one component of the behavioral response to stressful situation is active locomotion. We wondered if the routine postpartum handling undergone by foals, would affect their level of reactivity or the way they express their stress, when older. One single prolonged bout of handling just after birth clearly affected later adult expression of stress reactivity. In social separation associated with novelty, handled, and unhandled horses produced an equal amount of whinnies, showing a similar vocal response to stress. However, both groups differed in their locomotor response to the situations. Early handled foals expressed less of the active forms of locomotion than the control group. Our findings highlight the need of further reflections on long-term effects of routine handlings procedures close to birth

The Fermat-Torricelli problem in normed planes and spaces

We investigate the Fermat-Torricelli problem in d-dimensional real normed spaces or Minkowski spaces, mainly for d=2. Our approach is to study the Fermat-Torricelli locus in a geometric way. We present many new results, as well as give an exposition of known results that are scattered in various sources, with proofs for some of them. Together, these results can be considered to be a minitheory of the Fermat-Torricelli problem in Minkowski spaces and especially in Minkowski planes. This demonstrates that substantial results about locational problems valid for all norms can be found using a geometric approach