Hubble Space Telescope High Resolution Imaging of Kepler Small and Cool Exoplanet Host Stars

High resolution imaging is an important tool for follow-up study of exoplanet candidates found via transit detection with the Kepler Mission. We discuss here HST imaging with the WFC3 of 23 stars that host particularly interesting Kepler planet candidates based on their small size and cool equilibrium temperature estimates. Results include detections, exclusion of background stars that could be a source of false positives for the transits, and detection of physically-associated companions in a number of cases providing dilution measures necessary for planet parameter refinement. For six KOIs, we find that there is ambiguity in which star hosts the transiting planet(s), with potentially strong implications for planetary characteristics. Our sample is evenly distributed in G, K, and M spectral types. Albeit with a small sample size, we find that physically-associated binaries are more common than expected at each spectral type, reaching a factor of 10 frequency excess at M. We document the program detection sensitivities, detections, and deliverables to the Kepler follow-up program archive.Comment: Accepted for the Astronomical Journal; 13 pages with 9 figure

Hemodynamic and physical performance during maximal exercise in patients with an aortic bioprosthetic valve Comparison of stentless versus stented bioprostheses

AbstractOBJECTIVESThe objective of this study was to compare stentless bioprostheses with stented bioprostheses with regard to their hemodynamic behavior during exercise.BACKGROUNDStentless aortic bioprostheses have better hemodynamic performances at rest than stented bioprostheses, but very few comparisons were performed during exercise.METHODSThirty-eight patients with normally functioning stentless (n = 19) or stented (n = 19) bioprostheses were submitted to a maximal ramp upright bicycle exercise test. Valve effective orifice area and mean transvalvular pressure gradient at rest and during peak exercise were successfully measured using Doppler echocardiography in 30 of the 38 patients.RESULTSAt peak exercise, the mean gradient increased significantly less in stentless than in stented bioprostheses (+5 ± 3 vs. +12 ± 8 mm Hg; p = 0.002) despite similar increases in mean flow rates (+137 ± 58 vs. +125 ± 65 ml/s; p = 0.58); valve area also increased but with no significant difference between groups. Despite this hemodynamic difference, exercise capacity was not significantly different, but left ventricular (LV) mass and function were closer to normal in stentless bioprostheses. Overall, there was a strong inverse relation between the mean gradient during peak exercise and the indexed valve area at rest (r = 0.90).CONCLUSIONSHemodynamics during exercise are better in stentless than stented bioprostheses due to the larger resting indexed valve area of stentless bioprostheses. This is associated with beneficial effects with regard to LV mass and function. The relation found between the resting indexed valve area and the gradient during exercise can be used to project the hemodynamic behavior of these bioprostheses at the time of operation. It should thus be useful to select the optimal prosthesis given the patient’s body surface area and level of physical activity

Clinical and biological characteristics of cervical neoplasias with FGFR3 mutation

BACKGROUND: We have previously reported activating mutations of the gene coding for the fibroblast growth factor receptor 3 (FGFR3) in invasive cervical carcinoma. To further analyze the role of FGFR3 in cervical tumor progression, we extended our study to screen a total of 75 invasive tumors and 80 cervical intraepithelial neoplasias (40 low-grade and 40 high-grade lesions). RESULTS: Using single strand conformation polymorphism (SSCP) followed by DNA sequencing, we found FGFR3 mutation (S249C in all cases) in 5% of invasive cervical carcinomas and no mutation in intraepithelial lesions. These results suggest that, unlike in bladder carcinoma, FGFR3 mutation does not or rarely occur in non invasive lesions. Compared to patients with wildtype FGFR3 tumor, patients with S249C FGFR3 mutated tumors were older (mean age 64 vs. 49.4 years, P = 0.02), and were more likely to be associated with a non-16/18 HPV type in their tumor. Gene expression analysis demonstrated that FGFR3 mutated tumors were associated with higher FGFR3b mRNA expression levels compared to wildtype FGFR3 tumors. Supervised analysis of Affymetrix expression data identified a significant number of genes specifically differentially expressed in tumors with respect to FGFR3 mutation status. CONCLUSION: This study suggest that tumors with FGFR3 mutation appear to have distinctive clinical and biological characteristics that may help in defining a population of patients for FGFR3 mutation screening

Le mentorat en début de carrière : retombées sur la charge professorale et conditions de mise en œuvre d’un programme en milieu universitaire

Cette synthèse d’écrits a été menée dans le but de faire état des retombées du mentorat en milieu éducatif, plus précisément, le mentorat destiné aux enseignants universitaires en début de carrière et des conditions de mise en œuvre d’un programme. Les principaux constats tirés de cette synthèse montrent que la question du mentorat informel par rapport au mentorat formel reste sans réponse définitive quant à la supériorité d’une forme sur l’autre. De plus, en dépit des divergences de points de vue dans la littérature, il ressort que le mentorat joue un rôle positif dans le développement professionnel des nouveaux enseignants pour l’ensemble des fonctions composant leur charge professorale, incluant la fonction enseignement. Enfin, les expériences menées dans différents établissements nous permettent d’examiner des modalités d’implantation et de fonctionnement ainsi que de proposer un modèle de mentorat en trois étapes.This review of the literature was carried out in order to assess the impact of mentoring in educational settings and in particular mentoring addressing faculty in early stages of their academic career and the necessary requirements for implementing programmes. The main issues raised by our study indicate that as far as informal mentoring and formal mentoring are concerned there is no definite answer regarding the efficiency of one over the other. Furthermore despite contrasted views in the literature, it seems that mentoring does have a positive impact on professional development of early stage academics for most of the components of their professorial function including teaching. Last of all experiences carried out in various institutions allowed us to examine implementation and practise in mentoring and to devise a framework comprising three steps

The cosmic gravitational wave background in a cyclic universe

Inflation predicts a primordial gravitational wave spectrum that is slightly ``red,'' i.e., nearly scale-invariant with slowly increasing power at longer wavelengths. In this paper, we compute both the amplitude and spectral form of the primordial tensor spectrum predicted by cyclic/ekpyrotic models. The spectrum is blue and exponentially suppressed compared to inflation on long wavelengths. The strongest observational constraint emerges from the requirement that the energy density in gravitational waves should not exceed around 10 per cent of the energy density at the time of nucleosynthesis.Comment: 4 pages, 3 figuer

Cosmological Constraints on f(G)f(G) Dark Energy Models

Modified gravity theories with the Gauss-Bonnet term $G=R^2-4R^{\mu\nu}R_{\mu\nu}+R^{\mu\nu\rho\sigma}R_{\mu\nu\rho\sigma}$ have recently gained a lot of attention as a possible explanation of dark energy. We perform a thorough phase space analysis on the so-called $f(G)$ models, where $f(G)$ is some general function of the Gauss-Bonnet term, and derive conditions for the cosmological viability of $f(G)$ dark energy models. Following the $f(R)$ case, we show that these conditions can be nicely presented as geometrical constraints on the derivatives of $f(G)$. We find that for general $f(G)$ models there are two kinds of stable accelerated solutions, a de Sitter solution and a phantom-like solution. They co-exist with each other and which solution the universe evolves to depends on the initial conditions. Finally, several toy models of $f(G)$ dark energy are explored. Cosmologically viable trajectories that mimic the $\Lambda$CDM model in the radiation and matter dominated periods, but have distinctive signatures at late times, are obtained.Comment: 17 pages, 3 figures; typos correcte

Cosmological Perturbations in a Big Crunch/Big Bang Space-time

A prescription is developed for matching general relativistic perturbations across singularities of the type encountered in the ekpyrotic and cyclic scenarios i.e. a collision between orbifold planes. We show that there exists a gauge in which the evolution of perturbations is locally identical to that in a model space-time (compactified Milne mod Z_2) where the matching of modes across the singularity can be treated using a prescription previously introduced by two of us. Using this approach, we show that long wavelength, scale-invariant, growing-mode perturbations in the incoming state pass through the collision and become scale-invariant growing-mode perturbations in the expanding hot big bang phase.Comment: 47 pages, 4 figure

Between Big City and Authentic Village: Branding the Small Chinese City

While recent academic research has already produced an impressive corpus on big cities such as Shanghai and Beijing, the small Chinese city has been mostly ignored. In this article, I suggest that consideration of the small city can bring a new perspective on the wider urban fabric of which it is an element. Although small city governments have embraced urban entrepreneurialism with the same enthusiasm as China’s big cities, different configurations of space, branding and the everyday have nevertheless resulted. My case study of Kaili in Guizhou province indicates that the small city exists in a complex relationship with the big city and the village; it is pulled towards large-scale urbanization while simultaneously attempting to construct a unique city image based upon the evocation of rural cultural practices. The perspective from the small city thus suggests the need to consider the rural-urban divide – long a dominant geographical imagination of China – alongside other geographies, including a triad of the small city, the village and the big city

Prevalence of nonmedical methamphetamine use in the United States

<p>Abstract</p> <p>Background</p> <p>Illicit methamphetamine use continues to be a public health concern in the United States. The goal of the current study was to use a relatively inexpensive methodology to examine the prevalence and demographic correlates of nonmedical methamphetamine use in the United States.</p> <p>Methods</p> <p>The sample was obtained through an internet survey of noninstitutionalized adults (n = 4,297) aged 18 to 49 in the United States in 2005. Propensity weighting methods using information from the U.S. Census and the 2003 National Survey on Drug Use and Health (NSDUH) were used to estimate national-level prevalence rates.</p> <p>Results</p> <p>The overall prevalence of current nonmedical methamphetamine use was estimated to be 0.27%. Lifetime use was estimated to be 8.6%. Current use rates for men (0.32%) and women (0.23%) did not differ, although men had a higher 3-year prevalence rate (3.1%) than women (1.1%). Within the age subgroup with the highest overall methamphetamine use (18 to 25 year olds), non-students had substantially higher methamphetamine use (0.85% current; 2.4% past year) than students (0.23% current; 0.79% past year). Methamphetamine use was not constrained to those with publicly funded health care insurance.</p> <p>Conclusion</p> <p>Through the use of an internet panel weighted to reflect U.S. population norms, the estimated lifetime prevalence of methamphetamine use among 18 to 49 year olds was 8.6%. These findings give rates of use comparable to those reported in the 2005 NSDUH. Internet surveys are a relatively inexpensive way to provide complimentary data to telephone or in-person interviews.</p