From a Kac-like particle system to the Landau equation for hard potentials and Maxwell molecules

We prove a quantitative result of convergence of a conservative stochastic particle system to the solution of the homogeneous Landau equation for hard potentials. There are two main difficulties: (i) the known stability results for this class of Landau equations concern regular solutions and seem difficult to extend to study the rate of convergence of some empirical measures; (ii) the conservativeness of the particle system is an obstacle for (approximate) independence. To overcome (i), we prove a new stability result for the Landau equation for hard potentials concerning very general measure solutions. Due to (ii), we have to couple, our particle system with some non independent nonlinear processes, of which the law solves, in some sense, the Landau equation. We then prove that these nonlinear processes are not so far from being independent. Using finally some ideas of Rousset [25], we show that in the case of Maxwell molecules, the convergence of the particle system is uniform in time

Guerre des sexes chez une fourmi : reproduction clonale des mâles et des reines

NewsSCOPUS: no.jinfo:eu-repo/semantics/publishe

On the rate of convergence in Wasserstein distance of the empirical measure

Let $\mu_N$ be the empirical measure associated to a $N$-sample of a given probability distribution $\mu$ on $\mathbb{R}^d$. We are interested in the rate of convergence of $\mu_N$ to $\mu$, when measured in the Wasserstein distance of order $p>0$. We provide some satisfying non-asymptotic $L^p$-bounds and concentration inequalities, for any values of $p>0$ and $d\geq 1$. We extend also the non asymptotic $L^p$-bounds to stationary $\rho$-mixing sequences, Markov chains, and to some interacting particle systems

FROM A KAC-LIKE PARTICLE SYSTEM TO THE LANDAU EQUATION FOR HARD POTENTIALS AND MAXWELL MOLECULES

International audienceWe prove a quantitative result of convergence of a conservative stochastic particle system to the solution of the homogeneous Landau equation for hard potentials. There are two main difficulties: (i) the known stability results for this class of Landau equations concern regular solutions and seem difficult to extend to study the rate of convergence of some empirical measures; (ii) the conservativeness of the particle system is an obstacle for (approximate) independence. To overcome (i), we prove a new stability result for the Landau equation for hard potentials concerning very general measure solutions. Due to (ii), we have to couple, our particle system with some non independent nonlinear processes, of which the law solves, in some sense, the Landau equation. We then prove that these nonlinear processes are not so far from being independent. Using finally some ideas of Rousset [25], we show that in the case of Maxwell molecules, the convergence of the particle system is uniform in time

Date 2014-03-31

Title Interfaces the tandem protein identification algorithm in

Approche probabiliste pour l'analyse des tolérances des produits hyperstatiques – application à une pompe

International audienceL'analyse des tolérances des mécanismes a pour but d'évaluer la qualité du produit lors de sa phase de conception. La technique consiste à déterminer si, dans une production de grandes séries, le taux de rebuts des mécanismes défaillants est acceptable. Deux conditions doivent être vérifiées: une condition d'assemblage et une condition fonctionnelle. La méthode existante se base sur le couplage de la simulation de Monte Carlo avec un algorithme d'optimisation qui est très couteuse en temps de calcul. De ce fait, nous proposons une méthode plus efficace basée sur des approches probabilistes. Ces travaux ont permis le développement d'une nouvelle méthode de résolution basée sur la méthode de fiabilité système FORM (First Order Reliability Method) système. Cette méthode permet de traiter uniquement le problème fonctionnel. Ces performances sont illustrées sur un cas industriel : une pompe à débit variable

Les disparités de carrières des hommes et des femmes : accès à l'emploi, mobilités et salaires: Rapport final

Rapport final pour la DARES, Département des salaires, Convention n° 99 046L'étude s'est déroulé en trois volets qui structureront ce rapport. Dans un premier temps (partie I), il nous a semblé indispensable de situer notre analyse des disparités de carrières entre hommes et femmes dans l'évolution générale de l'activité et de l'emploi. Une analyse des différences hommes-femmes dans les enquêtes sur l'emploi de 1990 et 1999 a permis de constater : - que la concentration de l'emploi féminin par profession aurait plutôt tendance à se renforcer, ce qui n'est pas le cas de l'emploi masculin ;- que le mouvement général d'élévation de l'emploi précaire a plus touché les hommes que les femmes, réduisant l'écart entre les sexes ; celles-ci demeurant cependant plus concernées ;- enfin que le développement de l'emploi à temps partiel creuse l'écart entre les parcours professionnels et salariaux des hommes et des femmes en même temps qu'il crée des différenciations considérables au sein de la population féminine en emploi

Integration of a human risk module into a risk management software

In the scientific literature and in practice, many questionnaires based on a myriad of measures have been designed and tested to measure and evaluate perceived work stress or employee involvement. The objective of our research is to identify the most significant elements of human risks and to combine them into a single score at the level of teams and departments. Indeed, for companies, what really matters are the stress or dissatisfaction factors that lead to harmful behavior that prevent managers and their teams from achieving their objectives. Based on this research, we are developing a module that will be incorporated into the Oxial software and will also be available as a stand-alone module. This module will collect and analyze the data to calculate a single score measuring the level of human risk. This aspect is very innovative, because no risk management software currently includes a module dedicated to human risks

Improvement of Drosophila acetylcholinesterase stability by elimination of a free cysteine

BACKGROUND: Acetylcholinesterase is irreversibly inhibited by organophosphate and carbamate insecticides allowing its use for residue detection with biosensors. Drosophila acetylcholinesterase is the most sensitive enzyme known and has been improved by in vitro mutagenesis. However, it is not sufficiently stable for extensive utilization. It is a homodimer in which both subunits contain 8 cysteine residues. Six are involved in conserved intramolecular disulfide bridges and one is involved in an interchain disulfide bridge. The 8(th) cysteine is not conserved and is present at position 290 as a free thiol pointing toward the center of the protein. RESULTS: The free cysteine has been mutated to valine and the resulting protein has been assayed for stability using various denaturing agents: temperature, urea, acetonitrile, freezing, proteases and spontaneous-denaturation at room temperature. It was found that the C290V mutation rendered the protein 1.1 to 2.7 fold more stable depending on the denaturing agent. CONCLUSION: It seems that stabilization resulting from the cysteine to valine mutation originates from a decrease of thiol-disulfide interchanges and from an increase in the hydrophobicity of the buried side chain

Amplification of the poorer ear by StereoBiCROS in case of asymmetric sensorineural hearing loss: effect on tinnitus

Tinnitus is prevalent among patients suffering from Single-Sided Deafness (SSD) and Asymmetrical Hearing Loss (AHL). In addition to bothersome tinnitus in the poorer ear, these patients also report issues with understanding speech in noise and sound localization. The conventional treatment options offered to these patients to improve auditory abilities are cochlear implantation, bone conduction devices or Contralateral Routing Of Signal (CROS) hearing aids. It was recently found that the benefit of cochlear implantation for tinnitus associated with AHL/SSD was greater than the other two approaches. It is conceivable that the lack of stimulation provided to the poorer ear in these last approaches explains their modest impact on tinnitus perception. A new technology that combines the ability to reroute the sound from the poorer ear to the good ear (CROS system) while still stimulating the poorer ear with conventional sound amplification has recently been developed: the StereoBiCROS system. The aim of this study was to investigate the effects of this new device on tinnitus. Twelve AHL and two SSD patients aged 70.7 ± 7.9 years with tinnitus were fitted with bilateral hearing aids that included 3 programs: Stereophonic, BiCROS and StereoBiCROS (CROS + bilateral amplification). The short-and long-term effect of the approach on tinnitus was assessed using a tinnitus Loudness Visual Analog Scale (VAS) and the Tinnitus Handicap Inventory (THI), respectively. Both the VAS and the THI were used before and one month after the hearing aid fitting. Of the 14 patients who used their hearing aids daily (12.6 ± 1.6 h per day) the StereoBiCROS program was the most used program (81.8 ± 20.5% of the time). The average THI total score decreased from 47 (± 22) to 15 (± 16) (p = 0.002) and the VAS-Loudness score decreased from 7 (± 1) to 2 (± 2) (p < 0.001) after the one-month trial period. In conclusion, StereoBiCROS stimulation strategy seems to offer an effective alternative to reduce tinnitus handicap and loudness for patients with AHL/SSD and tinnitus. This effect may be driven by sound amplification of the poorer ear