Accurate spectroscopic parameters of WASP planet host stars

in Monthly Notices of the Royal Astronomical Society (2013), 428(4), 3164-3172

We have made a detailed spectral analysis of eleven Wide Angle Search for Planets (WASP) planet host stars using high signal-to-noise (S/N) HARPS spectra. Our line list was carefully selected from the ... [more ▼]

We have made a detailed spectral analysis of eleven Wide Angle Search for Planets (WASP) planet host stars using high signal-to-noise (S/N) HARPS spectra. Our line list was carefully selected from the spectra of the Sun and Procyon, and we made a critical evaluation of the atomic data. The spectral lines were measured using equivalent widths. The procedures were tested on the Sun and Procyon prior to be being used on the WASP stars. The effective temperature, surface gravity, microturbulent velocity and metallicity were determined for all the stars. We show that abundances derived from high S/N spectra are likely to be higher than those obtained from low S/N spectra, as noise can cause the equivalent width to be underestimated. We also show that there is a limit to the accuracy of stellar parameters that can be achieved, despite using high S/N spectra, and the average uncertainty in effective temperature, surface gravity, microturbulent velocity and metallicity is 83 K, 0.11 dex, 0.11 km/s and 0.10 dex respectively. [less ▲]

Flux and color variations of the doubly imaged quasar UM673

in Astronomy and Astrophysics (2013)

With the aim of characterizing the flux and color variations of the multiple components of the gravitationally lensed quasar UM673 as a function of time, we have performed multi-epoch and multi-band ... [more ▼]

With the aim of characterizing the flux and color variations of the multiple components of the gravitationally lensed quasar UM673 as a function of time, we have performed multi-epoch and multi-band photometric observations with the Danish 1.54m telescope at the La Silla Observatory. The observations were carried out in the VRi spectral bands during four seasons (2008--2011). We reduced the data using the PSF (Point Spread Function) photometric technique as well as aperture photometry. Our results show for the brightest lensed component some significant decrease in flux between the first two seasons (+0.09/+0.11/+0.05 mag) and a subsequent increase during the following ones (-0.11/-0.11/-0.10 mag) in the V/R/i spectral bands, respectively. Comparing our results with previous studies, we find smaller color variations between these seasons as compared with previous ones. We also separate the contribution of the lensing galaxy from that of the fainter and close lensed component. [less ▲]

A Detailed X-Ray Investigation of ζ Puppis. II. The Variability on Short and Long Timescales

in The Astrophysical Journal (2013), 763

Stellar winds are a crucial component of massive stars, but their exact properties still remain uncertain. To shed some light on this subject, we have analyzed an exceptional set of X-ray observations of ... [more ▼]

Stellar winds are a crucial component of massive stars, but their exact properties still remain uncertain. To shed some light on this subject, we have analyzed an exceptional set of X-ray observations of ζ Puppis, one of the closest and brightest massive stars. The sensitive light curves that were derived reveal two major results. On the one hand, a slow modulation of the X-ray flux (with a relative amplitude of up to 15% over 16 hr in the 0.3-4.0 keV band) is detected. Its characteristic timescale cannot be determined with precision, but amounts from one to several days. It could be related to corotating interaction regions, known to exist in ζ Puppis from UV observations. Hour-long changes, linked to flares or to the pulsation activity, are not observed in the last decade covered by the XMM observations; the 17 hr tentative period, previously reported in a ROSAT analysis, is not confirmed either and is thus transient, at best. On the other hand, short-term changes are surprisingly small (<1% relative amplitude for the total energy band). In fact, they are compatible solely with the presence of Poisson noise in the data. This surprisingly low level of short-term variability, in view of the embedded wind-shock origin, requires a very high fragmentation of the stellar wind, for both absorbing and emitting features (>10[SUP]5[/SUP] parcels, comparing with a two-dimensional wind model). This is the first time that constraints have been placed on the number of clumps in an O-type star wind and from X-ray observations. Based on observations collected with XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member States and the USA (NASA). [less ▲]

Validation methodologies of near infrared spectroscopy methods in pharmaceutical applications

in European Pharmaceutical Review (2013), 18(1), 3-6

As any analytical methods, a mandatory step at the end of the development of a near infrared spectroscopy (NIRS) method is the validation. This step enables to give enough guarantees that each future ... [more ▼]

As any analytical methods, a mandatory step at the end of the development of a near infrared spectroscopy (NIRS) method is the validation. This step enables to give enough guarantees that each future results coming from the application of the method in routine will be closed enough to the true value. However, from the literature, a minority of NIRS methods are thoroughly validated despite of the guidelines published by different group and regulatory authorities to help analyst to adequately decide if his method can be considered as valid. In this context, the aim of this review is to offer a critical overview of the different validation methodologies applied to assess the validity of quantitative methods using near infrared spectroscopy used in the field of pharmacy. [less ▲]

Robustness of steel building structures following a column loss

in IABSE Workshop Helsinki 2013 "Safety, Failures and Robustness of Large Structures" Report (2013, February)

La transition des territoires périurbains vers un modèle plus durable : perspectives pour le renouvellement périurbain.

in 1er Congrès interdisciplinaire du Développement Durable : Quelle transition pour nos sociétés ? Thème 3 : Logement et Aménagement du territoire. Recueil. (2013, February)

L’article aborde la question du recyclage des quartiers périurbains existants sous l'angle énergétique. Deux leviers d’actions sont mobilisés à cet effet : la forme urbaine, qui est étudiée en ... [more ▼]

L’article aborde la question du recyclage des quartiers périurbains existants sous l'angle énergétique. Deux leviers d’actions sont mobilisés à cet effet : la forme urbaine, qui est étudiée en complémentarité de l’échelle du bâtiment individuel, et la mobilité, car l’étalement urbain est entretenu et favorisé, en grande partie par la dépendance à la voiture individuelle. Deux indicateurs principaux (les besoins de chauffage de différents types de formes périurbaines et un indice de performance des déplacements) sont développés et discutés pour mettre en évidence les scénarios de renouvellement les plus adaptés et répondre à deux questions : « comment intervenir dans les quartiers périurbains existants ? » et « où intervenir ? ». Des pistes concrètes visant à l’opérationnalisation d’un « renouvellement périurbain » plus durable sont ensuite proposées. [less ▲]

Geometric minimization of highly symmetric potentials

in Journal of High Energy Physics [=JHEP] (2013), 2013

In non-minimal Higgs mechanisms, one often needs to minimize highly symmetric Higgs potentials. Here we propose a geometric way of doing it, which, surprisingly, is often much more efficient than the ... [more ▼]

In non-minimal Higgs mechanisms, one often needs to minimize highly symmetric Higgs potentials. Here we propose a geometric way of doing it, which, surprisingly, is often much more efficient than the usual method. By construction, it gives the global minimum for any set of free parameters of the potential, thus offering an intuitive understanding of how they affect the vacuum expectation values. For illustration, we apply this method to the S_4 and A_4-symmetric three-Higgs-doublet models. We find that at least three recent phenomenological analyses of the A_4-symmetric model used a local, not the global minimum. We discuss coexistence of minima of different types, and comment on the mathematical origin of geometrical CP-violation and on a new symmetry linking different minima. [less ▲]

Long term measurements of volatile organic compounds exchanges above a maize field at Lonzee (Belgium)

in Communications in Agricultural and Applied Biological Sciences (2013, February), 78(1), 127-132

VOC (volatile organic compounds) include a wide set of molecules which are mostly emitted by the plants. Atmospheric scientists are strongly interested in these compounds because of their important role ... [more ▼]

VOC (volatile organic compounds) include a wide set of molecules which are mostly emitted by the plants. Atmospheric scientists are strongly interested in these compounds because of their important role in the atmospheric chemistry and their final impact on air pollution and climate change. Evaluation of current and future VOC emissions is thus necessary and requires a comprehensive understanding of VOC production and exchange dynamics under a wide panel of climatic conditions and ecosystems. Forest and non pastured grasslands have been largely studied for the last decade. However, knowledge about VOC fluxes from croplands remains scarce. Our study focuses on the VOC exchanges between a maize field and the atmosphere. It is incorporated in a wider project that aims to study VOC fluxes from two croplands (maize and winter wheat) and a pastured grassland. VOC fluxes have been measured on a maize field during the whole growing season using a micrometeorological method (eddy covariance). While first results show half-hourly bidirectionnal exchanges among all the preselected compounds, in average methanol stands for the greatest emitted VOC, followed by green leaf volatiles, and acetic acid is the greatest taken up VOC. Small isoprene and monoterpenes fluxes are also observed. A diurnal pattern is found for all those VOC, with greater emission/uptake during the day, suggesting a flux dependence on environmental parameters. These environmental controls will be further investigated [less ▲]

Social Security and Economic Integration

E-print/Working paper (2013)

Children’s Knowledge About Memory: Adaptation and French Validation of a Scale to Assess it.

(2013, February)

The present study aimed at adapting and testing a French version of Kreutzer et al.’s metamemory interview (1975) in a group of 128 children aged of 4, 6, 9, and 12. Following Fritz et al. (2010 ... [more ▼]

The present study aimed at adapting and testing a French version of Kreutzer et al.’s metamemory interview (1975) in a group of 128 children aged of 4, 6, 9, and 12. Following Fritz et al. (2010), adjustments have been made to reduce language skill contamination as well as to increase the developmental appropriateness and sensibility of the scale. Results show the emergence of two sub-scales (“strategy knowledge” and “general memory knowledge”) on the factor analysis and reveal an excellent interrater reliability as well as a good internal consistency for the global scale and two sub-scales (respectively, Cronbach α = .79; .81 and .71). As expected with regard to the literature, a significant correlation has appeared between the metamemory scale and short-term memory capacities (convergent validity). Similarly, the metamemory score has shown its ability to predict children memory performance (predictive validity). Finally, the lack of correlation between most of the scale’s items and vocabulary measurement (Peabody Picture Vocabulary Test) and the very good ability of the scale to distinguish between age groups demonstrate that the adaptations made to improve the Kreutzer et al.’s scale in terms of language’s contamination and developmental sensibility have reached their goal. Regarding its psychometric properties, these results suggest that this interview can be considered as a useful and reliable tool for developmental research. Furthermore, they confirm the importance of metamemory knowledge in memory performance. Future studies will have to be carried out to show the utility of this scale in a clinical population. [less ▲]