Searches for very rare decays to purely leptonic final states at LHCb

We present a review of the searches for very rare decays to muonic final states performed at LHCb using 1.0 fb-1 of pp collisions at 7 TeV centre of mass energy. Flavour changing neutral current processes, such as B->mumu and B->mumumumu are highly suppressed in the Standard Model (SM). Such decays therefore allow contributions from new processes or new heavy particles to significantly modify the expected SM rates. Charged lepton flavour violating processes, such as the neutrino-less tau->mumumu decay, have vanishingly small decay rates in the SM, but can be significantly enhanced in extended models. We report the latest results on these channels from LHCb.Comment: 6 pages, 5 figures, ICHEP 2012: 36th International Conference on High Energy Physics, Melbourne, Australi

Variation of prostate-specific antigen value in men and risk of high-grade prostate vancer : analysis of the prostate, lung, colorectal, and ovarian cancer screening trial study

To investigate variations in prostate-specific antigen (PSA) levels among men with an initial normal PSA level in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial study. Data were extracted from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial study data set on all men in the interventional arm, with 2 tests performed in a period of < 2 years and with an initial result of the first test <4 ng/mL. The range of variation between first and second tests was computed. Risks of cancer stratified on Gleason score were computed using logistic regression. A total of 31,286 men had 2 PSA tests within 2 years and with an initial value < 4 ng/mL. From the first to the second test, the median variation of PSA levels was 3.4% (interquartile range, -15% to +26%). The variation in PSA value was not associated with the delay between the first and the second test (P = .36), age (P = .16), body mass index (P = .41), and race (P = .12). A total of 2,781 prostate cancers were diagnosed during follow-up. Adjusting for age and initial PSA level, the risk of prostate cancer increased linearly with increasing PSA level at the second test, with an odds ratio of 1.079 (95% confidence interval, 1.058-1.101) for each percent increase in PSA level. However, the variation in PSA was not associated with a higher Gleason score (P = .95 for level variations in cancer of Gleason score < 7 vs ≥ 7). Although an increase in PSA level over time is associated with increased risk of prostate cancer, this association is not related to more aggressive tumors

Carrier recombination dynamics in InGaN/GaN multiple quantum wells

We have mesured the carrier recombination dynamics in InGaN/GaN multiple quantum wells over an unprecedented range in intensity. We find that at times shorter than 30\,ns, they follow an exponential form, and a power law at times longer than 1\,$\mu$s. To explain these biphasic dynamics, we propose a simple three-level model where a charge-separated state interplays with the radiative state through charge transfer following a tunneling mechanism. We show how the distribution of distances in charge-separated states controls the dynamics at long time. Our results imply that charge recombination happens on nearly-isolated clusters of localization centers.Comment: 11 pages, 3 figures, accepted for publication in PHYSICAL REVIEW

Atomistic calculations of Ga(NAsP)/GaP(N) quantum wells on silicon substrate: Band structure and optical gain

International audienceBand structure calculations of strained Ga(NAsP) quantum wells are performed within the framework of the extended-basis sp3d5s* tight-binding model. The nitrogen contribution is taken into account by introducing an additional sN orbital into the tight-binding basis. Biaxial strain effects on the band alignment of bulk Ga(NAsP) is studied for the ultra-diluted regime. We demonstrate a good agreement with experimental data both for transition energies and optical gain in Ga(NAsP) quantum wells. The effect of N incorporation in the laser active areas is simulated

Probing superfluidity in a quasi two-dimensional Bose gas through its local dynamics

International audienceWe report direct evidence of superfluidity in a quasi two-dimensional Bose gas by observing its dynamical response to a collective excitation. Relying on a novel local correlation analysis, we are able to probe inhomogeneous clouds and reveal their local dynamics. We identify in this way the superfluid and thermal phases inside the gas and locate the boundary at which the Berezinskii--Kosterlitz--Thouless crossover occurs. This new analysis also allows to evidence the coupling of the two fluids which induces at finite temperatures damping rates larger than the usual Landau damping

L'Inspection du Travail au féminin, 1878-1974. Itinéraires et statuts

rapport dactylographié à la DARES, 2 tomes; le 2e tome est un annuaire des Inspectrices du Travail, 1878-1974La loi de 1892 qui scelle la professionnalisation de l'Inspection du travail — avec un concours de recrutement national, la rémunération des inspecteurs et inspectrices par le Ministère — n'organise pas exactement le même métier pour les Inspecteurs que pour les Inspectrices. Si la rémunération est convenue identique (ce qui n'est pas le cas dans l'enseignement), par contre les lieux d'exercice diffèrent ; ainsi seuls les Inspecteurs peuvent visiter des ateliers comprenant une majorité d'hommes et/ou des machines et ce n'est qu'en 1932 qu'une épreuve technique est incluse dans leur concours. Lors des conflits et des arbitrages du Front populaire, l'activité des inspectrices montre qu'elles sont confinées dans des secteurs à main-d'œuvre très féminine et où dominent les petites entreprises. Par ailleurs, les femmes sont, par le texte de la loi de 1892, exclues de la promotion, puisque seuls les Inspecteurs peuvent accéder au grade d'Inspecteur divisionnaire, c'est-à-dire celui de la responsabilité et du commandement sur les autres. Jusqu'à la Seconde guerre mondiale, pour ces quelques dizaines d'inspectrices, les recrutements sont rares, les concours féminins s'ouvrent rarement (tous les six ou sept ans) et la concurrence y est rude. De fait, le recrutement est plus compétitif aux inspectrices qu'aux inspecteurs ; les centaines de candidates qui se présentent pour sont bien plus diplômées que leurs confrères et font même partie des « pionnières » pour l'acquisition des diplômes de l'enseignement supérieur. La hauteur de leurs diplômes correspond à celle des maris et des pères: une moitié de ces femmes sont filles et épouses d'industriels, de négociants, d'hommes des professions libérales où dominent les médecins. Si ces Inspectrices sont des femmes actives, elle ne travaillent donc pas par nécessité financière, ni par désœuvrement familial (elles sont mères de famille pour les deux tiers d'entre elles), mais bien par souci d'équité sociale et/ou de réalisation individuelle. À partir de 1946, avec la mise en place du Statut de la fonction publique et surtout de 1974, avec la mixité des concours de recrutements des fonctionnaires, des mutations égalitaires s'organisent. À partir de 1946, les circonscriptions deviennent mixtes, les Inspectrices peuvent organiser la mobilité géographique qui permet la promotion. Pourtant, même si les textes du Statut énoncent l'égalité, les Inspectrices n'accèdent toujours pas aux grades qui autorisent la prise décision et l'autorité sur les autres, en particulier comme directeur régional du travail : il faut attendre 1974 pour que leurs carrières commencent à être comparables à celles de leurs collègues masculins. 1974 est aussi la date de la fusion des corps de l'Inspection, avec l'intégration des Inspecteurs de l'Agriculture et des Transports, où les femmes étaient toujours interdites de concours de recrutement

Differential Dynamic Microscopy to characterize Brownian motion and bacteria motility

We have developed a lab work module where we teach undergraduate students how to quantify the dynamics of a suspension of microscopic particles, measuring and analyzing the motion of those particles at the individual level or as a group. Differential Dynamic Microscopy (DDM) is a relatively recent technique that precisely does that and constitutes an alternative method to more classical techniques such as dynamics light scattering (DLS) or video particle tracking (VPT). DDM consists in imaging a particle dispersion with a standard light microscope and a camera. The image analysis requires the students to code and relies on digital Fourier transform to obtain the intermediate scattering function, an autocorrelation function that characterizes the dynamics of the dispersion. We first illustrate DDM on the textbook case of colloids where we measure the diffusion coefficient. Then we show that DDM is a pertinent tool to characterize biologic systems such as motile bacteria i.e.bacteria that can self propel, where we not only determine the diffusion coefficient but also the velocity and the fraction of motile bacteria. Finally, so that our paper can be used as a tutorial to the DDM technique, we have joined to this article movies of the colloidal and bacterial suspensions and the DDM algorithm in both Matlab and Python to analyze the movies

Endogenous and exogenous testosterone and the risk of prostate cancer and increased prostate-specific antigen (PSA) level: a meta-analysis

Objective: To review and quantify the association between endogenous and exogenoustestosterone and prostate-specific antigen (PSA) and prostate cancer. Methods: Literature searches were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Prospectivecohort studies that reported data on the associations between endogenous testosterone and prostate cancer, and placebo-controlled randomized trials of testosterone replacement therapy (TRT) that reported data on PSA and/or prostate cancer cases were retained. Meta-analyses were performed using random-effects models, with tests for publication bias and heterogeneity. Results: Twenty estimates were included in a meta-analysis, which produced a summary relative risk (SRR) of prostate cancer for an increase of 5 nmol/L of testosterone of 0.99 (95% confidence interval [CI] 0.96, 1.02) without heterogeneity (I2 = 0%).Based on 26 trials, the overall difference in PSA levels after onset of use of TRT was 0.10 ng/mL (-0.28, 0.48). Results were similar when conducting heterogeneity analyses by mode of administration, region, age at baseline, baseline testosterone, trial duration, type of patients and type of TRT. The SRR of prostate cancer as an adverse effect from 11 TRT trials was 0.87 (95% CI0.30; 2.50). Results were consistent across studies. Conclusions: Prostate cancer appears to be unrelated to endogenous testosterone levels. TRT for symptomatic hypogonadism does not appear to increase PSA levels nor the risk of prostate cancer development. The current data are reassuring, although some caution is essential until multiple studies with longer follow-up are available

VCSEL Based on InAs Quantum-Dashes With a Lasing Operation Over a 117-nm Wavelength Span

International audienceWe report an InP based vertical cavity surface emitting laser (VCSEL) achieving a lasing operation between 1529 and 1646 nm. This optically-pumped VCSEL includes a wide-gain bandwidth active region based on InAs quantum dashes and wideband dielectric Bragg mirrors. Based on a wedge microcavity design, we obtain a spatial dependence of the resonant wavelength along the wafer, enabling thus to monitor the gain material bandwidth. We demonstrate a 117 nm continuous wavelength variation of the VCSEL emission, a consequence of the important and wide gain afforded by the use of optimized quantum dashes

Ruling out Stellar Companions and Resolving the Innermost Regions of Transitional Disks with the Keck Interferometer

With the Keck Interferometer, we have studied at 2 um the innermost regions of several nearby, young, dust depleted "transitional" disks. Our observations target five of the six clearest cases of transitional disks in the Taurus/Auriga star-forming region (DM Tau, GM Aur, LkCa 15, UX Tau A, and RY Tau) to explore the possibility that the depletion of optically thick dust from the inner disks is caused by stellar companions rather than the more typical planet-formation hypothesis. At the 99.7% confidence level, the observed visibilities exclude binaries with flux ratios of at least 0.05 and separations ranging from 2.5 to 30 mas (0.35 - 4 AU) over >= 94% of the area covered by our measurements. All targets but DM Tau show near-infrared excess in their SED higher than our companion flux ratio detection limits. While a companion has previously been detected in the candidate transitional disk system CoKu Tau/4, we can exclude similar mass companions as the typical origin for the clearing of inner dust in transitional disks and of the near-infrared excess emission. Unlike CoKu Tau/4, all our targets show some evidence of accretion. We find that all but one of the targets are clearly spatially resolved, and UX Tau A is marginally resolved. Our data is consistent with hot material on small scales (0.1 AU) inside of and separated from the cooler outer disk, consistent with the recent SED modeling. These observations support the notion that some transitional disks have radial gaps in their optically thick material, which could be an indication for planet formation in the habitable zone (~ a few AU) of a protoplanetary disk.Comment: 36 pages, 7 figures. Accepted for publication in Ap