Invisible Decays of the Supersymmetric Higgs and Dark Matter

We discuss effects of the light sparticles on decays of the lightest Higgs in a supersymmetric model with nonuniversal gaugino masses at the high scale, focusing on the `invisible' decays into neutralinos. These can impact significanlty the discovery possibilities of the lightest Higgs at the LHC. We show that due to these decays, there exist regions of the $M_2-\mu$ space where the B.R. $(h \to \gamma \gamma)$ becomes dangerously low even after imposing the LEP constraints on the sparticle masses, implying a possible preclusion of its discovery in the $\gamma \gamma$ channel. We find that there exist regions in the parameter space with acceptable relic density and where the ratio ${B.R. (h \to \gamma \gamma)_{SUSY} \over B.R. (h \to \gamma \gamma)_{SM}}$ falls below 0.6, implying loss of signal in the $\gamma \gamma$ channel. These regions correspond to $\tilde \chi_1^+, \tilde \chi_2^0$ masses which should be accessible already at the Tevatron. Further we find that considerations of relic density put lower limit on the U(1) gaugino mass parameter $M_1$ independently of $\mu, \tan \beta$ and $m_0$.Comment: 17 pages, 11 figures, Talk presented at Appi2002, Accelerator and Particle Physics Institute, Appi, Iwate, Japan, February 13--16 200

Néo-fordisme et néo-étatisme: la convergence anti-démocratique

Ce texte a été écrit en 1968 pour une présentation au colloque international : Pouvoir politique et économie mondiale tenu à l'université Lavai. Il devrait faire partie d'un recueil qui n'a pas dépassé le stade de projet. Il est présenté id sans aucune modification

Les instances de représentation des salariés dans l'établissement : les cas de l'Allemagne, de la France et de l'Europe

Suite à une résolution de la CSN suggérant « l'adoption d'une loi-cadre prévoyant que soient partagées avec les représentants syndicaux, les informations économiques, les projets d'investissement, les projets de rationalisation ou de réorganisation et que le syndicat soit reconnu comme étant l'interlocuteur avec lequel ces matières devront être négociées et mises en place » (CSN, 59e Congrès, p. 7), une recherche sur les conseils d'établissement en Europe, où de tels droits sont accordés à des instances représentatives, nous semble incontournable. Nous ferons ici la recension des principaux écrits concernant les instances de représentation des salariés dans l'établissement en France, en Allemagne et à l'échelle de l'Union européenne. Cette étude se divise en deux parties couvrant deux facettes indispensables à la compréhension de la dynamique de ces instances, c'est-à-dire l'analyse de leur cadre légal et de ce que font les acteurs de l'autonomie dont ils disposent sur la base de ces codifications légales. La définition du cadre légal dans lequel évoluent les acteurs doit être établie, mais ne suffit pas à la compréhension du phénomène. Les positions adoptées par les acteurs, la reconnaissance et la légitimité d'action, les réseaux créés entre groupes d'acteurs et la culture organisationnelle sont autant d'éléments débordant le simple cadre juridique et qui influencent grandement les résultats obtenus par l'implantation de telles mesures. Ce n'est donc que suite à l'analyse de cette seconde facette organisationnelle que nous pourrons plus distinctement établir la comparaison

Tobacco and cannabis use trajectories from adolescence to young adulthood

The main objective of this longitudinal research is to answer the following question: What is the relationship between tobacco and cannabis use trajectories from adolescence to young adulthood? And more specifically we are interested in: A. If the use of one of the substances (tobacco or cannabis) decreases overtime, does the use of the other one increase to compensate? Are other substances (such as alcohol, for example) also used to compensate in these cases? B. Does the probability to become a tobacco smoker increase when cannabis use is heavier or has lasted longer? C. What are the risk and protective factors that can predict that the use of tobacco and/or cannabis will increase or decrease overtime

Periodic Modulations in an X-ray Flare from Sagittarius A*

We present the highly significant detection of a quasi-periodic flux modulation with a period of 22.2 min seen in the X-ray data of the Sgr A* flare of 2004 August 31. This flaring event, which lasted a total of about three hours, was detected simultaneously by EPIC on XMM-Newton and the NICMOS near-infrared camera on the HST. Given the inherent difficulty in, and the lack of readily available methods for quantifying the probability of a periodic signal detected over only several cycles in a data set where red noise can be important, we developed a general method for quantifying the likelihood that such a modulation is indeed intrinsic to the source and does not arise from background fluctuations. We here describe this Monte Carlo based method, and discuss the results obtained by its application to a other XMM-Newton data sets. Under the simplest hypothesis that we witnessed a transient event that evolved, peaked and decayed near the marginally stable orbit of the supermassive black hole, this result implies that for a mass of 3.5 x 10^{6} Msun, the central object must have an angular momentum corresponding to a spin parameter of a=0.22.Comment: 4 pages, 6 figures, submitted to ApJ

Association between physical activity motives and type of physical activity in children

Abstract: Objectives: Motives for participating in a specific type of physical activity (PA) may differ across PA type in youth. We studied the relationship between PA motives and type of PA engaged in by youth. Design: Cross-sectional analysis using data from the Monitoring Activities of Teenagers to Comprehend their Habits (MATCH) study. Method: 802 students age 10-11 years from 17 primary schools in New-Brunswick, Canada completed a questionnaire that collected data on type of PA participated in (individual, group-based, organized, non-organized), PA motives (enjoyment, social affiliation, competence, fitness/health, appearance) and attainment of PA guidelines (60 minutes of moderate-to-vigorous PA per day). The associations between PA motives and PA type and between PA motives and attainment of PA recommendations were assessed in multilevel logistic regression models. Results: Endorsing enjoyment motives was associated with participation in organized PA (Odds Ratio, 95% Confidence Interval: 1.54, 1.24-1.91). Competence motives were associated with participation in group-based PA (1.27, 1.11-1.46) and achievement of PA recommendations (1.95, 1.37-2.78). Conclusion: Targeting enjoyment and competence motives may be associated with increased participation in organized and group-based PA as well as with an increased likelihood of meeting PA guidelines in youth

Phenomenological Aspects of Gauge Mediation with Sequestered Supersymmetry Breaking in light of Dark Matter Detection

In a recent work, a model of gauge mediation with sequestered supersymmetry (SUSY) breaking was proposed. In this model, the mass of the gravitino is O(100) GeV without causing the flavor-changing neutral-current problem. In contrast to traditional gauge mediation, the gravitino is not the lightest SUSY particle and the neutralino is the candidate of the dark matter. In this paper, we investigate phenomenological aspects of this model and discuss the possibility of the direct detection of the dark matter. In particular, we focus on the light neutralino case and find that the light-Higgsino scenario such as the focus point is interesting, taking account of the recent CDMS result.Comment: 17 pages, 8 figures; v2:references added, some corrections; v3:version accepted for publication in JHE

Proteomic analysis of the metabolic adaptation of the biocontrol agent Pseudozyma flocculosa leading to glycolipid production

The yeast-like epiphytic fungus Pseudozyma flocculosa is known to antagonize powdery mildew fungi through proliferation on colonies presumably preceded by the release of an antifungal glycolipid (flocculosin). In culture conditions, P. flocculosa can be induced to produce or not flocculosin through manipulation of the culture medium nutrients. In order to characterize and understand the metabolic changes in P. flocculosa linked to glycolipid production, we conducted a 2-DE proteomic analysis and compared the proteomic profile of P. flocculosa growing under conditions favoring the development of the fungus (control) or conducive to flocculosin synthesis (stress). A large number of protein spots (771) were detected in protein extracts of the control treatment compared to only 435 matched protein spots in extracts of the stress cultures, which clearly suggests an important metabolic reorganization in slow-growing cells producing flocculosin. From the latter treatment, we were able to identify 21 protein spots that were either specific to the treatment or up-regulated significantly (2-fold increase). All of them were identified based on similarity between predicted ORF of the newly sequenced genome of P. flocculosa with Ustilago maydis' available annotated sequences. These proteins were associated with the carbon and fatty acid metabolism, and also with the filamentous change of the fungus leading to flocculosin production. This first look into the proteome of P. flocculosa suggests that flocculosin synthesis is elicited in response to specific stress or limiting conditions

A near-IR variability study of the Galactic black hole: a red noise source with no detected periodicity

We present the results of near-infrared (2 and 3 microns) monitoring of Sgr A*-IR with 1 min time sampling using the natural and laser guide star adaptive optics (LGS AO) system at the Keck II telescope. Sgr A*-IR was observed continuously for up to three hours on each of seven nights, between 2005 July and 2007 August. Sgr A*-IR is detected at all times and is continuously variable, with a median observed 2 micron flux density of 0.192 mJy, corresponding to 16.3 magnitude at K'. These observations allow us to investigate Nyquist sampled periods ranging from about 2 minutes to an hour. Using Monte Carlo simulations, we find that the variability of Sgr A* in this data set is consistent with models based on correlated noise with power spectra having frequency dependent power law slopes between 2.0 to 3.0, consistent with those reported for AGN light curves. Of particular interest are periods of ~20 min, corresponding to a quasi-periodic signal claimed based upon previous near-infrared observations and interpreted as the orbit of a 'hot spot' at or near the last stable orbit of a spinning black hole. We find no significant periodicity at any time scale probed in these new observations for periodic signals. This study is sensitive to periodic signals with amplitudes greater than 20% of the maximum amplitude of the underlying red noise component for light curves with duration greater than ~2 hours at a 98% confidence limit.Comment: 37 pages, 2 tables, 17 figures, accepted by Ap