Influence of Workload on Auditory Evoked Potentials in a Single-stimulus Paradigm

Mental workload can be assessed via neurophysiological markers. Temporal features such as event related potentials (ERPs) are one of those which are very often described in the literature. However, most of the studies that evaluate their sensitivity to workload use secondary tasks. Yet potentials elicited by ignored stimuli could provide mental state monitoring systems with less intrusive probing methods. For instance, auditory probing systems could be used in adaptive driving or e-learning applications. This study evaluates how workload influences auditory evoked potentials (AEPs) elicited by a single-stimulus paradigm when probes are to be ignored. Ten participants performed a Sternberg memory task on a touchpad with three levels of difficulty plus a view-only condition. In addition, they performed two ecological tasks of their choice, one deemed easy (e.g. reading novels), and the other difficult (e.g. programming). AEPs were elicited thanks to pure tones presented during the memory task retention period, and during the whole extent of the external tasks. Performance and AEPs were recorded and analyzed. Participants’ accuracy decreased linearly with increasing workload, whereas the difference in amplitude between the P3 and its adjacent components, N2 and SW, increased. This reveals the relevance of this triphasic sequence for mental workload assessment

Iron and Nickel spectral opacity calculations in conditions relevant for pulsating stellar envelopes and experiments

Seismology of stars is strongly developing. To address this question we have formed an international collaboration OPAC to perform specific experimental measurements, compare opacity calculations and improve the opacity calculations in the stellar codes [1]. We consider the following opacity codes: SCO, CASSANDRA, STA, OPAS, LEDCOP, OP, SCO-RCG. Their comparison has shown large differences for Fe and Ni in equivalent conditions of envelopes of type II supernova precursors, temperatures between 15 and 40 eV and densities of a few mg/cm3 [2, 3, 4]. LEDCOP, OPAS, SCO-RCG structure codes and STA give similar results and differ from OP ones for the lower temperatures and for spectral interval values [3]. In this work we discuss the role of Configuration Interaction (CI) and the influence of the number of used configurations. We present and include in the opacity code comparisons new HULLAC-v9 calculations [5, 6] that include full CI. To illustrate the importance of this effect we compare different CI approximations (modes) available in HULLAC-v9 [7]. These results are compared to previous predictions and to experimental data. Differences with OP results are discussed.Comment: 4 pages, 3 figures, conference Inertial Fusion Sciences and Applications, Bordeaux, 12th to 16th September 2011; EPJ web of Conferences 201

Theoretical and experimental activities on opacities for a good interpretation of seismic stellar probes

Opacity calculations are basic ingredients of stellar modelling. They play a crucial role in the interpretation of acoustic modes detected by SoHO, COROT and KEPLER. In this review we present our activities on both theoretical and experimental sides. We show new calculations of opacity spectra and comparisons between eight groups who produce opacity spectra calculations in the domain where experiments are scheduled. Real differences are noticed with real astrophysical consequences when one extends helioseismology to cluster studies of different compositions. Two cases are considered presently: (1) the solar radiative zone and (2) the beta Cephei envelops. We describe how our experiments are performed and new preliminary results on nickel obtained in the campaign 2010 at LULI 2000 at Polytechnique.Comment: 6 pages, 4 figures, invited talk at SOHO2

Radiative properties of stellar plasmas and open challenges

The lifetime of solar-like stars, the envelope structure of more massive stars, and stellar acoustic frequencies largely depend on the radiative properties of the stellar plasma. Up to now, these complex quantities have been estimated only theoretically. The development of the powerful tools of helio- and astero- seismology has made it possible to gain insights on the interiors of stars. Consequently, increased emphasis is now placed on knowledge of the monochromatic opacity coefficients. Here we review how these radiative properties play a role, and where they are most important. We then concentrate specifically on the envelopes of $\beta$ Cephei variable stars. We discuss the dispersion of eight different theoretical estimates of the monochromatic opacity spectrum and the challenges we need to face to check these calculations experimentally.Comment: 6 pages, 5 figures, in press (conference HEDLA 2010

When Flexibility Is Stable: Implicit Long-Term Shaping of Olfactory Preferences

Preferences are traditionally assumed to be stable. However, empirical evidence such as preference modulation following choices calls this assumption into question. The evolution of such postchoice preference over long time spans, even when choices have been explicitly forgotten, has so far not been studied. In two experiments, we investigated this question by using a variant of the free choice paradigm: In a first session, participants evaluated the pleasantness of a number of odors. We then formed pairs of similarly rated odors, and asked participants to choose their favorite, for each pair. Participants were then presented with all odors again, and asked for another pleasantness rating. In a second session 1 week later, a third pleasantness rating was obtained, and participants were again asked to choose between the same options. Results suggested postchoice preference modulation immediately and 1 week after choice for both chosen and rejected options, even when choices were not explicitly remembered. A third experiment, using another paradigm, confirmed that choice can have a modulatory impact on preferences, and that this modulation can be long-lasting. Taken together, these findings suggest that although preferences appear to be flexible because they are modulated by choices, this modulation also appears to be stable over time and even without explicit recollection of the choice. These results bring a new argument to the idea that postchoice preference modulation could rely on implicit mechanisms, and are consistent with the recent proposal that cognitive dissonance reduction could to some extent be implicit

Etude de plusieurs échantillons variétaux de pommes de terre cuites à la vapeur

National audienc

Etude de plusieurs échantillons variétaux de pommes de terre cuites à la vapeur

National audienc

Contribution à la mesure de la familiarité et de la complexité d'arômes alimentaires . Pertinence de ces concepts pour expliquer les préfèrences des consommateurs

117 ref. *INRA Unité Régionale de Documentation BP 86510 21065 Dijon (cedex) Diplôme : Dr. d'Universit