Direct Detection of Giant Close-In Planets Around the Source Stars of Caustic-Crossing Microlensing Events

We propose a direct method to detect close-in giant planets orbiting stars in the Galactic bulge. This method uses caustic-crossing binary microlensing events discovered by survey teams monitoring the bulge to measure light from a planet orbiting the source star. When the planet crosses the caustic, it is more magnified than the source star; its light is magnified by two orders of magnitude for Jupiter size planets. If the planet is a giant close to the star, it may be bright enough to make a significant deviation in the light curve of the star. Detection of this deviation requires intensive monitoring of the microlensing light curve using a 10-meter class telescope for a few hours after the caustic. This is the only method yet proposed to directly detect close-in planets around stars outside the solar neighborhood.Comment: 4 pages, 2 figures. Submitted to ApJ Letter

Laser cooling of a nanomechanical resonator mode to its quantum ground state

We show that it is possible to cool a nanomechanical resonator mode to its ground state. The proposed technique is based on resonant laser excitation of a phonon sideband of an embedded quantum dot. The strength of the sideband coupling is determined directly by the difference between the electron-phonon couplings of the initial and final states of the quantum dot optical transition. Possible applications of the technique we describe include generation of non-classical states of mechanical motion.Comment: 5 pages, 3 figures, revtex

Angular Radii of Stars via Microlensing

We outline a method by which the angular radii of giant and main sequence stars in the Galactic bulge can be measured to a few percent accuracy. The method combines ground-based photometry of caustic-crossing bulge microlensing events, with a handful of precise astrometric measurements of the lensed star during the event, to measure the angular radius of the source, theta_*. Dense photometric coverage of one caustic crossing yields the crossing timescale dt. Less frequent coverage of the entire event yields the Einstein timescale t_E and the angle phi of source trajectory with respect to the caustic. The photometric light curve solution predicts the motion of the source centroid up to an orientation on the sky and overall scale. A few precise astrometric measurements therefore yield theta_E, the angular Einstein ring radius. Then the angular radius of the source is obtained by theta_*=theta_E(dt/t_E) sin(phi). We argue that theta_* should be measurable to a few percent accuracy for Galactic bulge giant stars using ground-based photometry from a network of small (1m-class) telescopes, combined with astrometric observations with a precision of ~10 microarcsec to measure theta_E. We find that a factor of ~50 times fewer photons are required to measure theta_E to a given precision for binary-lens events than single-lens events. Adopting parameters appropriate to the Space Interferometry Mission (SIM), ~7 min of SIM time is required to measure theta_E to ~5% accuracy for giant sources in the bulge. For main-sequence sources, theta_E can be measured to ~15% accuracy in ~1.4 hours. With 10 hrs of SIM time, it should be possible to measure theta_* to ~5% for \~80 giant stars, or to 15% for ~7 main sequence stars. A byproduct of such a campaign is a significant sample of precise binary-lens mass measurements.Comment: 13 pages, 3 figures. Revised version, minor changes, required SIM integration times revised upward by ~60%. Accepted to ApJ, to appear in the March 20, 2003 issue (v586

Early Advanced LIGO binary neutron-star sky localization and parameter estimation

2015 will see the first observations of Advanced LIGO and the start of the gravitational-wave (GW) advanced-detector era. One of the most promising sources for ground-based GW detectors are binary neutron-star (BNS) coalescences. In order to use any detections for astrophysics, we must understand the capabilities of our parameter-estimation analysis. By simulating the GWs from an astrophysically motivated population of BNSs, we examine the accuracy of parameter inferences in the early advanced-detector era. We find that sky location, which is important for electromagnetic follow-up, can be determined rapidly (~5 s), but that sky areas may be hundreds of square degrees. The degeneracy between component mass and spin means there is significant uncertainty for measurements of the individual masses and spins; however, the chirp mass is well measured (typically better than 0.1%).Comment: 4 pages, 2 figures. Published in the proceedings of Amaldi 1

The Galactic Halo from Microlensing

The status of the microlensing search for galactic dark matter in the form of massive astronomical compact halo objects (machos) is reviewed. Unresolved issues are discussed, as well as possible ways to solve these

Reconstruction microchirurgicale et prise en charge globale des patients porteurs de cancer ORL : l’importance d’une approche qualité et d’un circuit protocolisé [Microsurgical reconstruction and full management of patients with head and neck cancer: Importance of a quality approach and a circuit protocolisation]

Main of study: Management and surgical reconstruction of head and neck cancers remain a challenge. From the first consultation to surgery and radiotherapy, it is necessary to save time to ensure optimum treatment and better survival rates. Objectif: To establish a kind of quality approach to the management of patients with head and neck cancers. 54 patients who had microsurgical reconstruction after head and neck cancer were included in this study between 1997 and 2006. Results : Multiple data were considered: body mass index (BMI), ASA stage, age, existence of a pre-or postoperative radiotherapy, the surgeon's experience and the number of veins drainage. The success rate is superior when more than one draining vein is sutured to the flap for patients with a BMI > 20. Radiotherapy does not seem to affect the survival of the flap. Conclusion: According to current literature, the survival rate of these patients is better when the overall time care is less than 100 days. That period is possible with a perfect organization of the medical and paramedical team. Therefore, we propose to include these patients in a circuit protocolisation care, which saves time, to better inform patients and improve survival rates. Buts: la prise en charge et la reconstruction chirurgicale des cancers ORL restent un challenge. De la première consultation à la chirurgie et la radiothérapie, il est nécessaire de gagner du temps afin d’assurer une traitement optimum et un meilleur taux de survie. Objectif : établir une sorte d’approche qualité de la prise en charge des patients porteurs de cancers ORL. 54 patients qui ont bénéficié d’une reconstruction microchirurgicale suite à un cancer ORL ont été inclus dans cette étude entre 1997 et 2006. Résultats : plusieurs données ont été étudiées : l’index de masse corporelle (IMC), le stade ASA, l’âge, l’existence d’une radiothérapie pré ou post opératoire, l’expérience du chirurgien ainsi que le nombre de veines de drainage. Le taux de succès se révèle supérieur lorsque plus d’une veine de drainage est suturée au lambeau, pour des patients ayant un IMC > 20. La radiothérapie ne semble pas avoir de répercussion sur la survie du lambeau. Conclusion : conformément à la littérature actuelle, le taux de survie de ces patients est meilleur lorsque le temps global de prise en charge est inférieur à 100 jours. Ce délai court n’est possible qu’avec une parfaite organisation de l’équipe médicale et paramédicale. De ce fait, nous proposons d’inclure ces patients dans un circuit de prise en charge protocolisé, ce qui permet de gagner du temps, de mieux informer le patient et d’améliorer le taux de survie

Anomalous quantum chaotic behavior in nanoelectromechanical structures

It is predicted that for sufficiently strong electron-phonon coupling an anomalous quantum chaotic behavior develops in certain types of suspended electro-mechanical nanostructures, here comprised by a thin cylindrical quantum dot (billiard) on a suspended rectangular dielectric plate. The deformation potential and piezoelectric interactions are considered. As a result of the electron-phonon coupling between the two systems the spectral statistics of the electro-mechanic eigenenergies exhibit an anomalous behavior. If the center of the quantum dot is located at one of the symmetry axes of the rectangular plate, the energy level distributions correspond to the Gaussian Orthogonal Ensemble (GOE), otherwise they belong to the Gaussian Unitary Ensemble (GUE), even though the system is time-reversal invariant.Comment: 4 pages, pdf forma