Control of the Grushin equation: non-rectangular control region and minimal time

International audienceThis paper is devoted to the study of the internal null-controllability of the Grushin equation. We determine the minimal time of controllability for a large class of non-rectangular control region. We establish the positive result thanks to the fictitious control method and the negative one by interpreting the associated observability inequality as an $L^2$ estimate on complex polynomials

Oxygen reduction at thin dense La0.52Sr0.48Co0.18Fe0.82O3- δ electrodes: Part I: Reaction model and faradaic impedance

The faradaic impedance of oxygen reduction has been simulated for thin dense two-dimensional $${\text{La}}_{{0.52}} {\text{Sr}}_{{0.48}} {\text{Co}}_{{0.18}} {\text{Fe}}_{{0.82}} {\text{O}}_{{3 - \delta }}$$ electrodes in air at 600°C. The reaction model accounts for the defect chemistry of the ceramic films and includes bulk and surface pathways. It was demonstrated that the contribution of the surface pathway to the reaction was negligible due to the small length of triple phase boundary gas/electrode/electrolyte. The diffusion of oxygen in the bulk of $${\text{La}}_{{0.52}} {\text{Sr}}_{{0.48}} {\text{Co}}_{{0.18}} {\text{Fe}}_{{0.82}} {\text{O}}_{{3 - \delta }}$$ (LSCF) can be evidenced by measuring the polarization resistance as a function of the electrode thickness that ranged between 10 and 800nm. When recorded as a function of the electrode potential and thickness, the frequency response exhibited features that were specific to the rate-determining steps of the reaction. The oxygen reduction mechanism and kinetics can therefore be identified by means of impedance spectroscopy. The faradaic impedances calculated for realistic values of the rate constants exhibited a noteworthy large faradaic capacitanc

Recent advances in laser-plasma experiments using foams

The paper discusses recent advances in the use of foams in laser–plasma experiments, concerning in particular: (1) the use of foam in order to get an efficient smoothing of laser energy deposition, (2) the problem of hydrodynamics of layered foam-payload targets, (3) the use of foam for shock pressure amplification in equation-of-state experiments, (4) the study of the equation of state of foams in the Megabar regime, and (5) the use of foams for astrophysics relevant experiments, here in particular shock acceleration experiments

The INOVE ANR 2010 Blan 0308 project: Integrated approach for observation and control of vehicle dynamics

International audienceThis paper presents the INOVE "Integrated approach for observation and control of vehicle dynamics" project. The aim and organization of the project are described and we present some recent results on the proposed integrated approach to design new methodologies for the improvement of the vehicle dynamical behaviour

Sex Differences in Semantic Processing: Event-Related Brain Potentials Distinguish between Lower and Higher Order Semantic Analysis during Word Reading

Behavioral studies suggest that women and men differ in the strategic elaboration of verbally encoded information especially in the absence of external task demand. However, measuring such covert processing requires other than behavioral data. The present study used event-related potentials to compare sexes in lower and higher order semantic processing during the passive reading of semantically related and unrelated word pairs. Women and men showed the same early context effect in the P1-N1 transition period. This finding indicates that the initial lexical-semantic access is similar in men and women. In contrast, sexes differed in higher order semantic processing. Women showed an earlier and longer lasting context effect in the N400 accompanied by larger signal strength in temporal networks similarly recruited by men and women. The results suggest that women spontaneously conduct a deeper semantic analysis. This leads to faster processing of related words in the active neural networks as reflected in a shorter stability of the N400 map in women. Taken together, the findings demonstrate that there is a selective sex difference in the controlled semantic analysis during passive word reading that is not reflected in different functional organization but in the depth of processin

An ecological momentary assessment study of age effects on perceptive and non-perceptive clinical high-risk symptoms of psychosis.

Among individuals with clinical high risk for psychosis (CHR), perceptive symptoms are more frequent but have less clinical significance in children/adolescents compared to adults. However, findings are based on clinical interviews relying on patient's recall capacity. Ecological momentary assessment (EMA) can be used to explore experiences in real-time in the subject's daily life. The aim of this study was to assess frequency and stability of (perceptive and non-perceptive) CHR symptoms and to explore potential age effects. EMA was used in a sample of an early detection for psychosis service in Bern, Switzerland (N = 66; 11-36 years). CHR symptoms were recorded in random time intervals for seven days: eight assessments per day per subject, minimum time between prompts set at 25 min. CHR symptoms were additionally assessed with semi-structured interviews including the 'Structured Interview for Psychosis-Risk Syndromes' and the 'Schizophrenia Proneness Instruments'. Mixed-effects linear regression analysis on the frequency of CHR symptoms revealed a significant effect of age group, and the interaction CHR symptoms x age group for both perceptive and non-perceptive symptoms. Further, regarding stability of CHR symptoms, there was a significant effect of the interaction CHR symptoms x age group for perceptive symptoms only. Based on EMA, perceptive CHR symptoms were more frequently reported but less stable in children/adolescents compared with adults. Together with previous findings, our finding of higher instability/variability of perceptive symptoms in younger persons might suggest that with advancing age and more stability of CHR symptoms, clinical relevance (reduced psychosocial functioning) may increase

On the small-time local controllability of a KdV system for critical lengths

This paper is devoted to the local null-controllability of the nonlinear KdV equation equipped the Dirichlet boundary conditions using the Neumann boundary control on the right. Rosier proved that this KdV system is small-time locally controllable for all non-critical lengths and that the uncontrollable space of the linearized system is of finite dimension when the length is critical. Concerning critical lengths, Coron and Cr\'{e}peau showed that the same result holds when the uncontrollable space of the linearized system is of dimension 1, and later Cerpa, and then Cerpa and Cr\'epeau established that the local controllability holds at a finite time for all other critical lengths. In this paper, we prove that, for a class of critical lengths, the nonlinear KdV system is {\it not} small-time locally controllable

Determination of the color temperature in laser-produced shocks

Experimental results on the determination of the color temperature in shock waves produced with lasers are presented. The method is based on imaging the target rear side in two different spectral windows and on using phased zone plates to produce high-quality shocks. The shock velocity is also measured, allowing, with the use of the equation of state, the real shock temperature to be deduced and compared with the measured color temperature

ACO2 mutations: A novel phenotype associating severe optic atrophy and spastic paraplegia

International audienc

Submillisecond unmasked subliminal visual stimuli evoke electrical brain responses

Subliminal perception is strongly associated to the processing of meaningful or emotional information and has mostly been studied using visual masking. In this study, we used high density 256-channel EEG coupled with an liquid crystal display (LCD) tachistoscope to characterize the spatio-temporal dynamics of the brain response to visual checkerboard stimuli (Experiment 1) or blank stimuli (Experiment 2) presented without a mask for 1 ms (visible), 500 µs (partially visible), and 250 µs (subliminal) by applying time-wise, assumption-free nonparametric randomization statistics on the strength and on the topography of high-density scalp-recorded electric field. Stimulus visibility was assessed in a third separate behavioral experiment. Results revealed that unmasked checkerboards presented subliminally for 250 µs evoked weak but detectable visual evoked potential (VEP) responses. When the checkerboards were replaced by blank stimuli, there was no evidence for the presence of an evoked response anymore. Furthermore, the checkerboard VEPs were modulated topographically between 243 and 296 ms post-stimulus onset as a function of stimulus duration, indicative of the engagement of distinct configuration of active brain networks. A distributed electrical source analysis localized this modulation within the right superior parietal lobule near the precuneus. These results show the presence of a brain response to submillisecond unmasked subliminal visual stimuli independently of their emotional saliency or meaningfulness and opens an avenue for new investigations of subliminal stimulation without using visual masking