Gardes à vue, 48h du polar à Clermont-Ferrand

Les festivals thématiques autour du polar se sont multipliés ces dernières années. Pourquoi et comment naît une telle manifestation, quels sont les ingrédients d’une recette réussie

GEOS RR Lyrae Database and Survey: A Professional-Amateur Project

GEOS, a European professional-amateur association, has collected in a database available times of maximum of RR Lyrae stars. We scanned the publications back to more than one century for this purpose. Recent observations are regularly added to the database. Measurements from amateur astronomer groups (GEOS, BAV, AAVSO) and from the robotic telescopes TAROT are used. To date, the database contains about 96 000 maximum times from 4 000 RR Lyrae stars. This database is particularly useful to study period variations of RR Lyrae stars including phenomena like the Blazhko effect and light travel time effects in binaries

N,N,N-Trimethyl chitosan as a permeation enhancer for inhalation drug delivery: interaction with a model pulmonary surfactant

N,N,N-Trimethyl chitosan (TMC), a biocompatible and biodegradable derivative of chitosan, is currently used as a permeation enhancer to increase the translocation of drugs to the bloodstream in the lungs. This article discusses the effect of TMC on a mimetic pulmonary surfactant, Curosurf, a low-viscosity lipid formulation administered to preterm infants with acute respiratory distress syndrome. Curosurf exhibits a strong interaction with TMC, resulting in the formation of aggregates at electrostatic charge stoichiometry. At nanoscale, Curosurf undergoes a profound reorganization of its lipid vesicles in terms of size and lamellarity. The initial micron-sized vesicles (average size 4.8 microns) give way to a froth-like network of unilamellar vesicles about 300 nm in size. Under such conditions, neutralization of the cationic charges by pulmonary surfactant may inhibit TMC permeation enhancer capacity, especially as electrostatic charge complexation is found at low TMC content. The permeation properties of pulmonary surfactant-neutralized TMC should then be evaluated for its applicability as a permeation enhancer for inhalation in the alveolar region.Comment: 20 pages, 7 figure

Cyclic Variations in the Periods of RR Lyrae Stars

We report here on two types of cyclic variations that can be observed in the periods of RR Lyrae stars, i.e., the Blazhko and the light-time effects. The former has been investigated by studying the amplitude variations recorded in RR Lyr itself, firstly by Kepler and then by the network of the ``Very Tiny Telescopes'' (VTTs), the latter on the basis of the new spectroscopic observations of the most promising candidate, KIC 2831097. The start of the search for binary candidates in the RR Lyrae stars observed with the TAROT telescopes is also announced

Quantum-Dash Mode-Locked Laser as a Source for 56-Gb/s DQPSK Modulation in WDM Multicast Applications

International audienceWe investigate wavelength tunable 56-Gb/s differential quaternary phase-shift keying (DQPSK) systems using comb generation in a quantum-dash mode-locked laser for wavelength-division-multiple access (WDM)-based broadcast application. We present relative intensity noise and bit-error-rate measurements for each mode. We demonstrate error-free operation over nine WDM channels with 100-GHz spacing

A peculiar galaxy appears at redshift 11: properties of a moderate redshift interloper

Laporte et al. (2011) reported a very high redshift galaxy candidate: a lensed J-band dropout (A2667-J1). J1 has a photometric redshift of z=9.6-12, the probability density function for which permits no low or intermediate z solution. We here report new spectroscopic observations of this galaxy with VLT/XShooter, which show clear [OIII]5007AA, Ly-alpha, H-alpha, and H-beta emission and place the galaxy firmly at z=2.082. The oxygen lines contribute only ~25% to the H-band flux, and do not significantly affect the dropout selection of J1. After correcting the broadband fluxes for line emission, we identify two roughly equally plausible natures for A2667-J1: either it is young heavily reddened starburst, or a maximally old system with a very pronounced 4000AA break, upon which a minor secondary burst of star formation is superimposed. Fits show that to make a 3 sigma detection of this object in the B-band (V-band), imaging of depth AB=30.2 (29.5) would be required - despite the relatively bright NIR magnitude, we would need optical data of equivalent depth to the Hubble Ultra Deep Field to rule out the mid-z solution on purely photometric grounds. Assuming that this stellar population can be scaled to the NIR magnitudes of recent HST/WFC3 IR-selected galaxies, we conclude that infeasibly deep optical data AB~32 would be required for the same level of security. There is a population of galaxies at z~2 with continuum colours alone that mimic those of our z=7-12 candidates.Comment: Accepted by Monthly Notices. 5 pages, 2 figure

Calcul d'algèbre de Frobenius sur l'homologie des lacets libres d'une variété.

Rédigée durant l'année 2005 à AngersIn 1999, M.Chas and D.Sullivan have constructed on the homology of free loop space of a manifold a BV-algebra structure. This was the begining of the String topology theory. In this thesis, we show the compatibility of the Serre spectral sequence to Gysin morphism of smooth finite codimensional embeddings between manifolds. Then, we use this technic to compute some examples of structures of string topology. We study essentially the “loop product” and the “loop coproduct” which provide the homology of free loop space of a manifold a stucture of Frobenius algebra without counit.En 1999, M.Chas et D.Sullivan ont mis en évidence sur l'homologie de l'espace des lacets libres d'une variété une structure de BV-algèbre. C'est ce qui fonde la théorie topologique des cordes. Dans cette thèse, nous montrons comment la compatibilité de la suite spectrale de Serre aux morphismes de Gysin de plongements lisses de codimension finie entre vari étés permet d'effectuer des calculs de ces structures de topologie des cordes. Nous étudions essentiellement le ”loop produit” et le ”loop coproduit” qui munissent l'homologie de l'espace des lacets libres d'une vari été d'une structure d'algèbre de Frobenius sans counité