The radius anomaly in the planet/brown dwarf overlapping mass regime

The recent detection of the transit of very massive substellar companions (CoRoT-3b, Deleuil et al. 2008; CoRoT-15b, Bouchy et al. 2010; WASP-30b, Anderson et al. 2010; Hat-P-20b, Bakos et al. 2010) provides a strong constraint to planet and brown dwarf formation and migration mechanisms. Whether these objects are brown dwarfs originating from the gravitational collapse of a dense molecular cloud that, at the same time, gave birth to the more massive stellar companion, or whether they are planets that formed through core accretion of solids in the protoplanetary disk can not always been determined unambiguously and the mechanisms responsible for their short orbital distances are not yet fully understood. In this contribution, we examine the possibility to constrain the nature of a massive substellar object from the various observables provided by the combination of Radial Velocity and Photometry measurements (e.g. M_p, R_p, M_s, Age, a, e...). In a second part, developments in the modeling of tidal evolution at high eccentricity and inclination - as measured for HD 80 606 with e=0.9337 (Naef et al. 2001), XO-3 with a stellar obliquity >37.3+-3.7 deg (H\'ebrard et al. 2008; Winn et al. 2009) and several other exoplanets - are discussed along with their implication in the understanding of the radius anomaly problem of extrasolar giant planets.Comment: Proceedings of the conference: "Detection and dynamics of transiting exoplanets" held at the OHP, 23-27 August 2010. 7 pages, 3 figure

Understanding exoplanet formation, structure and evolution in 2010

In this short review, we summarize our present understanding (and non-understanding) of exoplanet formation, structure and evolution, in the light of the most recent discoveries. Recent observations of transiting massive brown dwarfs seem to remarkably confirm the predicted theoretical mass-radius relationship in this domain. This mass-radius relationship provides, in some cases, a powerful diagnostic to distinguish planets from brown dwarfs of same mass, as for instance for Hat-P-20b. If confirmed, this latter observation shows that planet formation takes place up to at least 8 Jupiter masses. Conversely, observations of brown dwarfs down to a few Jupiter masses in young, low-extinction clusters strongly suggest an overlapping mass domain between (massive) planets and (low-mass) brown dwarfs, i.e. no mass edge between these two distinct (in terms of formation mechanism) populations. At last, the large fraction of heavy material inferred for many of the transiting planets confirms the core-accretion scenario as been the dominant one for planet formation.Comment: Invited review, IAU Symposium No. 276, The Astrophysics of Planetary Systems: Formation, Structure, and Dynamical Evolutio

Hydrodynamic modelling and the dispersion of water fecal contaminants in current and future climates

10 p.International audienceDuring precipitation events in regions with combined sewers, overflows can occur upstream of drinking water treatment plants. The purpose of the research was to model the transport and propagation of pathogens and pharmaceuticals in the Rivière Des Prairies during flood and low flow events. The water quality is quantified in terms of the behaviour of the river, the interactions of contaminants with the environment and the impacts of climate change. Hydrosim was used for hydrodynamic modeling; Dispersim was used to model the dispersion of contaminants. The impact of climate change was represented by the change of flow in the river. To do so, simulations were performed using Hydrotel, a hydrologic model applied to the Ottawa River. Thus, the impact of dispersion and diffusion of contaminants on the water quality were analyzed to determine the potential impact on raw water quality. Water quality will be affected by lower flows and heavy rains, which will change the frequency distributions of fecal contaminants upon which microbial risk models are based

Negative regulation of EB1 turnover at microtubule plus ends by interaction with microtubule-associated protein ATIP3

International audienceThe regulation of microtubule dynamics is critical to ensure essential cell functions. End binding protein 1 (EB1) is a master regulator of microtubule dynamics that autonomously binds an extended GTP/GDP-Pi structure at growing microtubule ends and recruits regulatory proteins at this location. However, negative regulation of EB1 association with growing microtubule ends remains poorly understood. We show here that microtubule-associated tumor suppressor ATIP3 interacts with EB1 through direct binding of a non-canonical proline-rich motif. Results indicate that ATIP3 does not localize at growing microtubule ends and that in situ ATIP3-EB1 molecular complexes are mostly detected in the cytosol. We present evidence that a minimal EB1-interacting sequence of ATIP3 is both necessary and sufficient to prevent EB1 accumulation at growing microtubule ends in living cells and that EB1-interaction is involved in reducing cell polarity. By fluorescence recovery of EB1-GFP after photobleaching, we show that ATIP3 silencing accelerates EB1 turnover at microtubule ends with no modification of EB1 diffusion in the cytosol. We propose a novel mechanism by which ATIP3-EB1 interaction indirectly reduces the kinetics of EB1 exchange on its recognition site, thereby accounting for negative regulation of microtubule dynamic instability. Our findings provide a unique example of decreased EB1 turnover at growing microtubule ends by cytosolic interaction with a tumor suppressor. INTRODUCTION Microtubules (MTs) are polarized structures that continuously switch between periods of polymerization and depolymerization at their growing (plus) ends. This process, termed MT dynamic instability, allows rapid reorganization of the MT cytoskeleton during essential cell functions such as cell polarity and migration, mitosi

The European Registered Toxicologist (ERT) : Current status and prospects for advancement

Acknowledgements We would like to thank the participants of the five workshops in which the issues presented in this paper were discussed and the revised guidelines prepared, as well as the EUROTOX Executive Committee and the societies of toxicology of Sweden, the Netherlands, Switzerland, Austria and France for their support which allowed the workshops to take place.Peer reviewedPostprin

The Lyot Project Direct Imaging Survey of Substellar Companions: Statistical Analysis and Information from Nondetections

The Lyot project used an optimized Lyot coronagraph with Extreme Adaptive Optics at the 3.63m Advanced Electro-Optical System telescope (AEOS) to observe 86 stars from 2004 to 2007. In this paper we give an overview of the survey results and a statistical analysis of the observed nondetections around 58 of our targets to place constraints on the population of substellar companions to nearby stars. The observations did not detect any companion in the substellar regime. Since null results can be as important as detections, we analyzed each observation to determine the characteristics of the companions that can be ruled out. For this purpose we use a Monte Carlo approach to produce artificial companions, and determine their detectability by comparison with the sensitivity curve for each star. All the non-detection results are combined using a Bayesian approach and we provide upper limits on the population of giant exoplanets and brown dwarfs for this sample of stars. Our nondetections confirm the rarity of brown dwarfs around solar-like stars and we constrain the frequency of massive substellar companions (M>40Mjup) at orbital separation between and 10 and 50 AU to be <20%.Comment: 32 pages, 11 figures, 2 tables. Published in the Astrophysical Journa

Effects of the oral endothelin-receptor antagonist bosentan on echocardiographic and doppler measures in patients with pulmonary arterial hypertension

OBJECTIVES The purpose of this study was to investigate the effects of bosentan (125 or 250 mg twice daily) on echocardiographic and Doppler variables in 85 patients with World Health Organization class III or IV pulmonary arterial hypertension (PAH). BACKGROUND Bosentan, an orally active dual endothelin-receptor antagonist, improves symptoms, exercise capacity, and hemodynamics in patients with PAH. METHODS Patients had primary pulmonary hypertension (84%) or PAH associated with connective tissue disease. Of these, 29 patients received placebo and 56 received bosentan (1:2 randomization). Six-minute walk tests and echocardiograms were performed at baseline and after 16 weeks of treatment. RESULTS Baseline characteristics were similar in the placebo and bosentan groups, and echocardiographic and Doppler findings were consistent with marked abnormalities of right ventricular (RV) and left ventricular (LV) structure and function that were due to PAH. The treatment effect on 6-min walking distance was 37 m in favor of bosentan (p = 0.036). Treatment effects of bosentan compared with placebo on other parameters were as follows: Doppler-derived cardiac index = + 0.4 l/min/m2(p = 0.007), LV early diastolic filling velocity = + 10.5 cm/s (p = 0.003), LV end-diastolic area = + 4.2 cm2(p = 0.003), LV systolic eccentricity index = -0.12 (p = 0.047), RV end-systolic area = -2.3 cm2(p = 0.057), RV:LV diastolic areas ratio = -0.64 (p = 0.007), Doppler RV index = -0.06 (p = 0.03), and percentage of patients with an improvement in pericardial effusion score = 17% (p = 0.05). CONCLUSIONS Bosentan improves RV systolic function and LV early diastolic filling and leads to a decrease in RV dilation and an increase in LV size in patients with PAH

Quelle est la place de l'échographie dans le dépistage du cancer du sein?

The main goal of a screening test for cancer is to reduce the cancer-related deaths. Mammography remains the only screening test that has been shown to improve survival from breast cancer. However, sensitivity of mammography decreases dramatically in young women and in women with dense breasts. Recently, several studies reported the value of whole breast ultrasound. On average more than 90% of the cancers detected only with ultrasound were invasive, stage 0 or 1, with an average size of 9 mm. However, none of these studies was the sonographer blinded to mammographic findings. Ultrasound requires no ionizing radiation, causes no breast discomfort and interventional procedures are easily performed. Standardized technique and interpretative criteria are required to avoid a high false-positive rate. © Masson, 2006

Spontaneous metritis related to the presence of vaginal septum in pregnant Sprague Dawley Crl:CD(SD) rats: impact on reproductive toxicity studies

Recently, 6% of 1,176 Sprague Dawley rats examined in our reproductive toxicity studies presented with dark-red uterine contents with or without fetuses demonstrating delayed development. Sometimes, a high proportion of the litter was found dead, and dystocia with death or preterminal euthanasia of the dam occurred. Microscopic findings in the uterus consisted of necrohemorrhagic and suppurative periplacentitis associated with the presence of bacterial colonies identified as Escherichia coli. In the vagina, similar findings were observed that were associated with mucus accumulation and the presence of a transverse occlusive or partially occlusive thin membrane identified as a vaginal septum. Microscopically, this septum consisted of a thin band of connective tissue covered on both sides by a mucous epithelium that was continuous with vaginal epithelium. In some cases, there was only mucus accumulation retained by a septum in the vagina without evidence of bacterial infection. Serological and histological examinations did not reveal any specific pathogenic agent. The presence of these septa in the vagina most likely favored mucus accumulation, nonspecific ascending bacterial infection, and dystocia. This colony of rats presented with an unusually high incidence of vaginal septa as it was described in different strains of mice and rats in the past. We hypothesized that the use of an impedance meter by the breeder--to determine the phase of the estrous cycle by introducing a probe in the vagina--likely facilitated gestation by perforating the vaginal septum in some cases