Speed of response initiation in a time-to-contact discrimination task reflects the use of η

AbstractAvoiding collisions and making interceptions seem to require an organism to estimate the time that will elapse before an object will arrive to the point of observation (time-to-contact). The most outstanding account for precise timing has been the tau hypothesis. However, recent studies demonstrate that tau is not the only source of information in judging time-to-contact. By measuring reaction time in a time-to-contact discrimination task, we show that the η function, which is a specific combination of optical size and rate of expansion, explains both accuracy and the observed RT pattern. The results conform to the hypothesis that the observers initiate the response when η reaches a response threshold value

Green functions and associated sources in infinite and stratified poroelastic media

International audienceThe purpose of this paper is to study Green functions for porous saturated media and to present an example of numerical simulation using these Green functions. In the first part the equations of the porous media are recalled and the principal results concerning the features of the waves are given. The second part is devoted to the determination of sources and Green functions. We give the analytical solution, then we study some of its properties. In the third part we focus on the construction of synthetic seismograms. We show examples of bi-dimensional computation in a semi-infinite stratified porous medium, for a double dipole or a fluid injection

One spatial filter limits speed of detecting low and middle frequency gratings

AbstractReaction times for detecting sinusoidal gratings depend jointly on grating contrast and spatial frequency. We examine whether the effect of spatial frequency results from low-pass filtering in a single channel or reflects processing of different frequencies by two or more different processing streams. Observers performed a speeded two-alternative spatial forced-choice detection. Errors and reaction times were measured. Contrasts varied from 0.05 to 0.67, and spatial frequencies from 0.72 to 6.51 cpd. No effect of uncertainty about spatial frequency was found, arguing against multiple channels. The data are well fit by a single channel model driven by a low pass filter

Randomized controlled study of fractional doses of inactivated poliovirus vaccine administered intradermally with a needle in the Philippines

SummaryObjectiveComparison of a fractional inactivated poliovirus vaccine (IPV) dose administered intradermally (ID) to a full dose administered intramuscularly (IM).MethodsHealthy Filipino infants were randomized to receive IPV as either a fractional (1/5th) dose ID by needle injection or a full dose IM at 6, 10, and 14 weeks and a booster at 15–18 months of age. Pre- and post-vaccination anti-polio 1, 2, and 3 titers were estimated. Adverse events were monitored throughout the study.ResultsFollowing primary series vaccination, anti-polio 1, 2, and 3 titers were ≥8 (1/dil) in 99–100% of participants, and the ID route was non-inferior to the IM route. Depending on the study group, antibody persistence was detected in 83–100% of participants, and the booster dose resulted in a strong anamnestic response in all groups. The incidence of adverse events in each group was similar, except for injection-site erythema (higher in the ID group).ConclusionsPrimary series and booster vaccination of a fractional IPV dose administered by the ID route was highly immunogenic and well tolerated. These data confirm the medical validity of using fractional ID doses of IPV. The programmatic feasibility of implementing affordable mass vaccination programs based on this delivery mode has yet to be established

Sciences, musiques, Lumières, Mélanges offerts à Anne-Marie Chouillet (I)

Vu la diversité des domaines qui y sont abordés, l’ouvrage offert à A.-M. Chouillet a fait l’objet de deux comptes rendus (NdlR). Les Mélanges offerts à Anne-Marie Chouillet (publiés par Ulla Kölving et Irène Passeron) répondent pleinement à la vocation du genre puisque ce recueil se présente, en effet, comme un hommage à une personnalité dont il rappelle le rayonnement. Ainsi peut-on mieux mesurer l’étendue des activités dix-huitiémistes de celle qui est ici honorée : que ce soit dans le tra..

Diderot dans les Lettres à Sophie Volland, Une esthétique épistolaire

Cet ouvrage est issu d’une thèse (soutenue en 1999) sous la direction de Georges Benrekassa qui a rédigé ici la préface. Odile Richard- Pauchet appartient à la fois à l’Association Interdisciplinaire de Recherche sur l’Épistolaire et à la Société Diderot. Toute la richesse de son travail tient à ce double ancrage institutionnel et disciplinaire. C’est avec beaucoup de brio et de solidité documentaire qu’elle fait à chaque fois le point sur les domaines qu’elle envisage et sur les questions qu..

Lectures de Jacques Proust

Il y aura bientôt quatre ans déjà que Jacques Proust nous a quittés, le 19 septembre 2005. L’année qui suivit fut marquée par des évocations du disparu dignes en tout point de lui : celle de Georges Benrekassa icimême (RDE n° 40-41), celles de Yoichi Sumi et de Hisayasu Nakagawa (accompagnées d’une bibliographie de Muriel Brot) dans Dix-huitième siècle (n° 38).Avec ces Lectures de Jacques Proust (et prochainement un Sillages de Jacques Proust édité par Marie Leca-Tsiomis) s’ouvre une autre sé..