Diderot et le temps, sous la direction de Stéphane Lojkine, Adrien Paschoud et Barbara Selmeci Castioni

Ce volume rassemble les actes d’un colloque en deux parties, dont la première s’est déroulée à Aix-en-Provence en 2013 et la seconde à Lausanne en 2014. Il contient vingt-quatre articles, répartis en quatre axes de réflexion : « Temps et épistémologie », « Le temps de la fiction », « Temps et esthétique », « Temps et éthique ». Bien que la répartition des articles soit inégale, l’ensemble des axes de réflexion présente un intérêt certain. Les deux volets de ce colloque ont eu lieu à la même p..

Hichem Ghorbel, Le Monde chez Diderot. Connaissance, interprétation et signification

Derrière ce titre séduisant, il est question de l’unité de la pensée philosophique de Diderot et de la vision matérialiste du monde qui en émerge. Hichem Ghorbel s’est donné pour objectif de montrer que la Lettre sur les aveugles, les Pensées sur l’interprétation de la nature et Le Rêve de D’Alembert s’articulent comme « un véritable triptyque » (p. 20) qui, pris comme tel, dessine en filigrane la représentation que le philosophe se faisait du monde. L’auteur constate en effet que ces trois œ..

Discrimination by Infrared Spectroscopy: Application to Micronized Locust Bean and Guar Gums

The authentication of locust bean and guar powder gums requires usually the use of sophisticated and time-consuming analytical techniques. There is a need for fast and simple analytical techniques for the objective of a quality control methodology. Commercial locust bean and guar micronized powder gums present characteristic MIR spectra. Principal component analysis of the infrared spectra of these micronized powder gums allowed to distinguish locust bean from guar samples and to perform good classification results. The prediction of the two varieties was done without any ambiguity with a partial least square regression-discriminant analysis (PLS-DA). A simplex approach was used to generate binary blends mathematically taking into account the intrinsic variability of chemical composition of commercial products. The simulated spectral profiles allowed to develop predictive model of the percentage of gums in blends

Vers un « Dictionnaire critique des lecteurs de Diderot ». Échantillons

Les effets des œuvres de Diderot sont si divers qu’il serait souhaitable d’entreprendre un Dictionnaire de ses lecteurs. On y trouverait des entrées correspondant à des spécialistes du philosophe, à des écrivains dont l’œuvre porte les traces visibles d’une lecture de Diderot, et d’autres, qui s’y réfèrent de façon plus discrète. Cette section réunit trois brèves études qui permettent d’esquisser un tel ouvrage. Fabien Girard rappelle que Balzac connaissait bien l’œuvre de Diderot à laquelle il fait régulièrement allusion. Nadège Langbour se demande si Jules Verne a pu se souvenir de Diderot en écrivant certains de ses romans. Enfin, Berenika Palus montre de quelle façon Diderot devient un personnage littéraire dans Semiramida, la pièce du dramaturge polonais Maciej Woltyszko crée en 1996.Jules Verne reads Diderot. Maciej Woltyszko’s Semiramida (1996) The effects of Diderot’s works are so diverse that it would be useful to undertake a dictionary of his readers, containing entries on specialists on Diderot, writers whose works show clear traces of having read him and others who refer to him more discreetly. This article brings together three short studies giving an idea of such a work. Fabien Girard reminds us that Balzac knew Diderot’s work very well and often referred to it ; Nadège Langbour wonders whether Jules Verne might have thought of Diderot when writing certain of his works ; and finally Berenika Palus shows how Diderot becomes a literary character in Semiramida, the play created in 1996 by the Polish playwright Maciej Woltyszko

Explicit uncertainty for eye movement selection

ISBN : 978-2-9532965-0-1In this paper, we consider the issue of the selection of eye movements in an eye-free Multiple Object Tracking task. We propose a Bayesian model of retinotopic maps with a complex logarithmic mapping. This model is structured in two parts: a representation of the visual scene, and a decision model based on the representation. We compare different decision models based on different features of the representation and we show that taking into account uncertainty helps predict the eye movements of subjects recorded in a psychophysics experiment

X-shooter, NACO, and AMBER observations of the LBV Pistol Star \footnote{Based on ESO runs 85.D-0182A, 085.D-0625AC}

We present multi-instruments and multi-wavelengths observations of the famous LBV star Pistol Star. These observations are part of a larger program about early O stars at different metallicities. The Pistol star has been claimed as the most massive star known, with 250 solar masses. We present the preliminary results based on X-Shooter spectra, as well as the observations performed with the VLTI-AMBER and the VLT-NACO adaptive optics. The X-shooter spectrograph allows to obtain simultaneously a spectrum from the UV to the K-band with a resolving power of $\sim$15000. The preliminary results obtained indicate that Pistol Star has similar properties of Eta Car, including shells of matter, but also the binarity. Other objects of the program, here briefly presented, were selected for their particular nature: early O stars with mass discrepancies between stellar evolution models and observations, discrepancies with the wind momentum luminosity relation.Comment: Poster at the 39th LIAC, submitted version of the proceeding

Discretized aperture mapping with a micro-lenses array for interferometric direct imaging

Discretized Aperture Mapping (DAM) appears as an original filtering technique easy to play with existing adaptive optics (AO) systems. In its essential DAM operates as an optical passive filter removing part of the phase residuals in the wavefront without introducing any difficult-to-align component in the Fourier conjugate of the entrance pupil plane. DAM reveals as a new interferometric technique combined with spatial filtering allowing direct imaging over a narrow field of view (FOV). In fact, the entrance pupil of a single telescope is divided into many sub-pupils so that the residual phase in each sub-pupil is filtered up to the DAM cut-off frequency. DAM enables to smooth the small scale wavefront defects which correspond to high spatial frequencies in the pupil plane and to low angular frequencies in the image plane. Close to the AO Nyquist frequency, such pupil plane spatial frequencies are not well measured by the wavefront sensor (WFS) due to aliasing. Once bigger than the AO Nyquist frequency, they are no more measured by the WFS due to the fitting limit responsible for the narrow AO FOV. The corresponding image plane angular frequencies are not transmitted by DAM and are useless to image small FOVs, as stated by interferometry. That is why AO and DAM are complementary assuming that the DAM cut-off frequency is equal to the AO Nyquist frequency. Here we describe the imaging capabilities when DAM is placed downstream an AO system, over a convenient pupil which precedes the scientific detector. We show firstly that the imaging properties are preserved on a narrow FOV allowing direct imaging throughout interferometry. Then we show how the residual pupil plane spatial frequencies bigger than the AO Nyquist one are filtered out, as well as the residual halo in the image is dimmed

Bayesian models of eye movement selection with retinotopic maps

Abstract Among the various possible criteria guiding eye movement selection, we investigate the role of position uncertainty in the peripheral visual field. In particular, we suggest that, in everyday life situations of object tracking, eye movement selection probably includes a principle of reduction of uncertainty. To evaluate this hypothesis, we confront the movement predictions of computational models with human results from a psychophysical task. This task is a freely moving eye version of the Multiple Object Tracking task, where the eye movements may be used to compensate for low peripheral resolution. We design several Bayesian models of eye movement selection with increasing complexity, whose layered structures are inspired by the neurobiology of the brain areas implied this process. Finally, we compare the relative performances of these models with regard to the prediction of the recorded human movements, and show th

High-angular resolution observations of the Pistol Star

First results of near-IR adaptive optics (AO)-assisted imaging, interferometry, and spectroscopy of this Luminous Blue Variable (LBV) are presented. They suggest that the Pistol Star is at least double. If the association is physical, it would reinforce questions concerning the importance of multiplicity for the formation and evolution of extremely massive stars.Comment: poster at IAUS27

Luminous blue variables: An imaging perspective on their binarity and near environment

Luminous blue variables (LBVs) are rare massive stars with very high luminosity. They are characterized by strong photo-metric and spectroscopic variability related to transient eruptions. The mechanisms at the origin of these eruptions is not well known. In addition, their formation is still problematic and the presence of a companion could help to explain how they form. Aims. This article presents a study of seven LBVs (about 20% of the known Galactic population), some Wolf-Rayet stars, and massive binaries. We probe the environments that surround these massive stars with near-, mid-, and far-infrared images, investigating potential nebula/shells and the companion stars. Methods. To investigate large spatial scales, we used seeing-limited and near diffraction-limited adaptive optics images to obtain a differential diagnostic on the presence of circumstellar matter and to determine their extent. From those images, we also looked for the presence of binary companions on a wide orbit. Once a companion was detected, its gravitational binding to the central star was tested. Tests include the chance projection probability, the proper motion estimates with multi-epoch observations, flux ratio, and star separations. Results. We find that two out of seven of LBVs may have a wide orbit companion. Most of the LBVs display a large circumstellar envelope or several shells. In particular, HD168625, known for its rings, possesses several shells with possibly a large cold shell at the edge of which the rings are formed. For the first time, we have directly imaged the companion of LBV stars