A Photometric Study of the Hot Exoplanet WASP-19b

in Astronomy and Astrophysics (2013), 552

Context. The sample of hot Jupiters that have been studied in great detail is still growing. In particular, when the planet transits its host star, it is possible to measure the planetary radius and the ... [more ▼]

Context. The sample of hot Jupiters that have been studied in great detail is still growing. In particular, when the planet transits its host star, it is possible to measure the planetary radius and the planet mass (with radial velocity data). For the study of planetary atmospheres, it is essential to obtain transit and occultation measurements at multiple wavelengths. Aims: We aim to characterize the transiting hot Jupiter WASP-19b by deriving accurate and precise planetary parameters from a dedicated observing campaign of transits and occultations. Methods: We have obtained a total of 14 transit lightcurves in the r'-Gunn, I-Cousins, z'-Gunn, and I + z' filters and 10 occultation lightcurves in z'-Gunn using EulerCam on the Euler-Swiss telescope and TRAPPIST. We also obtained one lightcurve through the narrow-band NB1190 filter of HAWK-I on the VLT measuring an occultation at 1.19 μm. We performed a global MCMC analysis of all new data, together with some archive data in order to refine the planetary parameters and to measure the occultation depths in z'-band and at 1.19 μm. Results: We measure a planetary radius of Rp = 1.376 ± 0.046 RJ, a planetary mass of Mp = 1.165 ± 0.068 MJ, and find a very low eccentricity of e = 0.0077-0.0032+0.0068, compatible with a circular orbit. We have detected the z'-band occultation at 3σ significance and measure it to be δFocc,z' = 352 ± 116 ppm, more than a factor of 2 smaller than previously published. The occultation at 1.19 μm is only marginally constrained at δFocc,NB1190 = 1711-726+745 ppm. Conclusions: We show that the detection of occultations in the visible range is within reach, even for 1 m class telescopes if a considerable number of individual events are observed. Our results suggest an oxygen-dominated atmosphere of WASP-19b, making the planet an interesting test case for oxygen-rich planets without temperature inversion. [less ▲]

La Bible comme moyen de "trans-port": le cas du "combat spirituel" de mama Olangi (Congo-Kinshasa)

in Laurent, Pierre-Joseph; Plaideau, Charlotte (Eds.) Dynamiques contemporaines de la mouvance pentecôtiste. Une analyse croisée Amérique-Afrique-Europe (2013)

Quelles activités pour nos seniors souffrant de maladie de la mémoire ?

Conference (2013, November 16)

WASP-71b: a bloated hot Jupiter in an 2.9-day, prograde orbit around an evolved F8 star

in Astronomy and Astrophysics (2013), 552

We report the discovery by the WASP transit survey of a highly-irradiated, massive (2.242 +/- 0.080 MJup) planet which transits a bright (V = 10.6), evolved F8 star every 2.9 days. The planet, WASP-71b ... [more ▼]

We report the discovery by the WASP transit survey of a highly-irradiated, massive (2.242 +/- 0.080 MJup) planet which transits a bright (V = 10.6), evolved F8 star every 2.9 days. The planet, WASP-71b, is larger than Jupiter (1.46 +/- 0.13 RJup), but less dense (0.71 +/- 0.16 {\rho}Jup). We also report spectroscopic observations made during transit with the CORALIE spectrograph, which allow us to make a highly-significant detection of the Rossiter-McLaughlin effect. We determine the sky-projected angle between the stellar-spin and planetary-orbit axes to be {\lambda} = 20.1 +/- 9.7 degrees, i.e. the system is 'aligned', according to the widely-used alignment criteria that systems are regarded as misaligned only when {\lambda} is measured to be greater than 10 degrees with 3-{\sigma} confidence. WASP-71, with an effective temperature of 6059 +/- 98 K, therefore fits the previously observed pattern that only stars hotter than 6250 K are host to planets in misaligned orbits. We emphasise, however, that {\lambda} is merely the sky-projected obliquity angle; we are unable to determine whether the stellar-spin and planetary-orbit axes are misaligned along the line-of-sight. With a mass of 1.56 +/- 0.07 Msun, WASP-71 was previously hotter than 6250 K, and therefore might have been significantly misaligned in the past. If so, the planetary orbit has been realigned, presumably through tidal interactions with the cooling star's growing convective zone. [less ▲]

Comment concilier flexibilité et sécurité en TPE/PME ?

Conference (2013, November)

Face à la libéralisation du marché, à l’externalisation des échanges et aux progrès technologiques, les entreprises doivent, à présent, jongler entre des dispositifs et des mesures destinés à assouplir le ... [more ▼]

Face à la libéralisation du marché, à l’externalisation des échanges et aux progrès technologiques, les entreprises doivent, à présent, jongler entre des dispositifs et des mesures destinés à assouplir le marché du travail, tout en procurant une certaine sécurité et stabilité à leur main-d’œuvre. C’est dans ce cadre que cette communication vise à comprendre et à saisir la manière dont les très petites entreprises (TPE) et les petites et moyennes entreprises (PME) belges francophones tentent de concilier flexibilité et sécurité dans ce contexte de mondialisation et de concurrence exacerbée (Auer, 2008). En d’autres termes, nous verrons d’une part, quels dispositifs de flexibilité et de sécurité ces deux types d’entreprise mobilisent dans leur gestion de l’emploi et d’autre part, dans quelle mesure ces dispositifs sont propres à leurs structures configurationnelles et pratiques de gestion des ressources humaines (GRH), à l’aune de la théorie de la contingence structurelle (Mintzberg, 1982 ; Pichault et Nizet, 2000). À l’aide de 67 entretiens semi-directifs réalisés au sein de 54 TPE/PME belges, nous déterminerons tout d’abord, les pratiques de GRH véhiculées sur base d’indicateurs de flexibilité et de sécurité préalablement définis et ensuite, le type de configuration prédominant en proposant un modèle explicatif des facteurs et enjeux influençant ces pratiques. [less ▲]

Industrial hazards and social factors: a question of vulnerability

Conference (2013, October 09)

In order to analyze and try to mitigate the potential consequences of a hazard threatening a complex socio-technical system, the risk analysis framework is classically used. Many risk analysis models ... [more ▼]

In order to analyze and try to mitigate the potential consequences of a hazard threatening a complex socio-technical system, the risk analysis framework is classically used. Many risk analysis models recognize now widely the importance of integrating social aspects into the analysis. Another way to deal with potential consequences of hazards is to analyze the vulnerability of the system considered. This paradigm overcomes the shortcomings of risk analysis in situations when the knowledge about the probabilities and the outcomes is incomplete or insufficient. Studies in the literature considering natural hazards show that socio-economic factors are integrated more often and in a natural way in vulnerability analysis models. Nevertheless, it seems that such considerations are missing into models aiming at evaluating the vulnerability to an industrial hazard, especially at a very local level where the technical aspects seem to be predominant. What can we learn from the analysis of the models addressing vulnerability to natural hazards in terms of the integration of social factors? To answer this question, we realized a systematic literature review from scientific journal papers on vulnerability analysis published in the last two decades. We synthesize this review and we propose an integrated vulnerability analysis model; in order to test this model we use as a case-study the incident reports collected in a nuclear facility in Belgium. This confrontation allows us to highlight important factors to be taken into account for a vulnerability analysis conducted in such a context. [less ▲]

Ticks of the trade: technical analysis self-justified

Conference (2013, October)

As opposed to fundamental analysis, financial chartism (or technical analysis) is based on the assumption that future movements of a traded asset can be inferred from past regularities. In spite, or maybe ... [more ▼]

As opposed to fundamental analysis, financial chartism (or technical analysis) is based on the assumption that future movements of a traded asset can be inferred from past regularities. In spite, or maybe by virtue of its lack of scientific grounds, it enjoys an ever-growing popularity among amateur traders, as countless websites provide free, simple and powerful tools for making professional-looking charts and even automate the detection of trends. Though technical analysts account for the validity of chart patterns in terms of market psychology, constructivist explanations also abound among trading communities: it is all as if economic agents reflexively used technical analysis as a means of coordination on the market. Markers like moving averages and trend lines serve as self-referent indicators whose efficacy only gets reinforced as more agents use it as pivotal points. Performativity is the technical analyst’s most natural language: explicit mentions to mechanisms such as the self-fulfilling prophecy or the Keynesian beauty contest are the only justifications s/he needs. Some chartists even claim their discipline does not contradict the efficient-market hypothesis: if prices already reflect all past publicly available information, one may skip the hassle of dissecting balance sheets or mastering pricing models, focusing instead on candlestick or diagram patterns which, by conjecture, contain all the necessary information to explain price movements. Drawing on the comparative analysis of nonprofessional trading blogs, our paper examines how these major epistemic modes of justification of technical analysis have come to support each other, in a context of proliferation of charting tools. [less ▲]

Questions anthropologiques et phénoménologie. Autour du travail de Daniel Giovannangeli

Book published by Ousia (2013)

Mobile speckle interferometer in the long-wave infrared for aeronautical nondestructive testing in field conditions

in Optical Engineering : The Journal of the Society of Photo-Optical Instrumentation Engineers (2013), 52(10),

Abstract We present the development of a speckle interferometer based on CO2 laser and using a thermal infrared camera based on uncooled microbolometer array. It is intended to be used for monitoring ... [more ▼]

Abstract We present the development of a speckle interferometer based on CO2 laser and using a thermal infrared camera based on uncooled microbolometer array. It is intended to be used for monitoring deformations as well as flaw detection in aeronautical composites, with a smaller sensitivity to displacement compared to equivalent system using visible lasers. Moreover the long wavelength allows working with such interferometer under out-of-laboratory conditions. A mobile system has been developed on the basis of previous laboratory developments. Then it is validated in a variety of industrial nondestructive testing applications under field working conditions. [less ▲]

Le Dieu de Maman Olangi. Ethnographie d'un combat spirituel transnational

Book published by Academia/L'Harmattan (2013)

Avec le « combat spirituel » du couple Olangi (Congo-Kinshasa), l’Afrique centrale revisite le pentecôtisme évangélique et offre une triangulation inédite d’un mouvement aujourd’hui séculaire et ... [more ▼]

Avec le « combat spirituel » du couple Olangi (Congo-Kinshasa), l’Afrique centrale revisite le pentecôtisme évangélique et offre une triangulation inédite d’un mouvement aujourd’hui séculaire et transnational. Une approche ethnographique translocale au plus proche des réalités vécues sur le terrain (Bruxelles-Kinshasa) a permis à l’auteur de rendre compte des imaginaires et des pratiques à l’œuvre dans un espace-temps du religieux qui a généré un ethos spirituel de combat. L’ethnographie des conversions au « Dieu de maman Olangi » révèle une radicalité singulière. Le combat comporte un enjeu fort d’émancipation de la parenté et de la famille. Elle est vécue comme un poids d’obligations à honorer davantage qu’un principe de solidarité qui prend ici des allures de dernier mythe africain. Ce combat spirituel est en prise directe avec l’expérience irréductible de la colonisation ainsi qu’avec les épreuves non moins irréductibles de l’expérience migratoire. Il trouve aujourd’hui à s’exercer dans n’importe quel lieu de la planète où quelques uns de ses disciples sont installés et contribue au développement d’une résilience dans laquelle l’idéologie dominante, capitaliste, fonctionne à plein régime. [less ▲]