Threshold constraints with guarantees for parity objectives in markov decision processes

The beyond worst-case synthesis problem was introduced recently by Bruyère et al. [10]: it aims at building system controllers that provide strict worst-case performance guarantees against an antagonistic environment while ensuring higher expected performance against a stochastic model of the environment. Our work extends the framework of [10] and follow-up papers, which focused on quantitative objectives, by addressing the case of ω-regular conditions encoded as parity objectives, a natural way to represent functional requirements of systems. We build strategies that satisfy a main parity objective on all plays, while ensuring a secondary one with sufficient probability. This setting raises new challenges in comparison to quantitative objectives, as one cannot easily mix different strategies without endangering the functional properties of the system. We establish that, for all variants of this problem, deciding the existence of a strategy lies in NP \ coNP, the same complexity class as classical parity games. Hence, our framework provides additional modeling power while staying in the same complexity class.SCOPUS: cp.pinfo:eu-repo/semantics/publishe

Perceived acculturation preferences of minority groups and intergroup discrimination: When culture-specific intergroup norms matter

International audienceThe present research seeks to show that culture‐specific variables can moderate the impact of general determinants of intergroup discrimination, usually assumed to operate identically across cultures. The present paper reports the results of two studies testing the hypothesis that, in France, the cultural norm of new laïcité (a French‐specific ideology of secularism) can moderate the impact of the perceived host culture adoption and national identification on discrimination against immigrants. We conducted a correlational study (Study 1, N = 249) and an experiment (Study 2, N = 143) using two distinct and previously validated measures of intergroup discrimination. Results showed that the higher the perception of a norm of new laïcité, the stronger the link between host culture adoption and national identification. More specifically, among native French people, the perception of a weak host culture adoption and a weak national identification on the part of immigrants produced higher levels of discriminatory behavior especially when the intergroup norm of new laïcité was high. These studies highlight the fundamental importance of taking into account culture‐specific variables in the study of discrimination and point to the fact that, by changing the normative context, one may change intergroup behaviors. Reducing intergroup discrimination in applied settings may require targeting culture‐specific intergroup norms

Adrenal cortex tissue homeostasis and zonation: A WNT perspective

International audienc

Social conditionality of attentional capture by angry faces: The role of group attitudes and SES

International audienceThe preferential selection of faces expressing negative emotions (such as fear or anger) is a recurrentfinding in experimental psychology. This effect is often used as an argument for theories of emotion thatconsider the selection of threat-related stimuli as an automatic and unconditional process. However,faces belong to a particular class of threat-related stimuli, since they are also important sources of socialinformation. This allows individuals to rapidly categorize people in different groups, and thus to differentiate efficiently “the friends from the foes”. Several studies have already demonstrated that this categorization process may impact cognition and behavior, with a general tendency to favor in-groupsand/or discriminate out-groups. We do not know whether and how this intergroup bias modulates attentional capture by faces expressing negative emotions. Rather than being fully automatic, we suggesthere that emotional capture depends on the social group to which the expressive individual and theobserver belong to. To address this issue, neutral and angry faces were presented as cues in a dot-probetask. Group membership was manipulated through the faces’ ethnicity (Caucasian or North-African), anddid or did not match the French participants’ ethnic group (study 1: Caucasian, study 2: North-African).Participants’ identification with the French group, as well as their implicit and explicit attitudes towardsthe Caucasian and North-African groups were also measured. In opposition to the unconditional view ofemotional selection, no attentional capture by angry faces was observed for Caucasian participants(study 1). In sharp contrast, a strong attentional capture by angry faces was observed for participantsfrom the North-African ethnic group (study 2). Importantly, this effect was modulated by the face’s ethnicity and group attitudes. Attentional capture by North-African angry faces was observed for highlyidentified participants to the French group, or who held the most negative implicit attitudes towardsNorth-African people. Symmetrically, attentional capture by Caucasian angry faces was observed for thelow-identified participants to the French group, or who held the most negative implicit attitudes towardsFrench people. Therefore, these new results suggest that intergroup bias can modulate attentional capture by negative faces, especially angry faces of the devalued group (the group the participants were lessidentified with, or held the most negative implicit attitudes to). Nonetheless, these effects were observed exclusively for participants from the North-African ethnic group. For that matter, previous studiesindicated that low socioeconomic status (SES) individuals are more sensitive to their surroundings, andespecially to potential threats in their environment, compared to high SES individuals. As it happens,belonging to the North-African ethnic group is also commonly associated with lower SES (in France). Wetherefore assumed that low SES may have been responsible of the heightened vigilance observed forthis group of participants. In order to test this hypothesis, a replication of the study with Caucasian participants including a measure of their objective SES is being carried out

Attentional bias modification with a new paradigm: The effect of the Detection Engagement and Savoring Positivity (DESP) task on eye-tracking of attention

International audienceBackground and Objectives: We test the effect of a new attentional bias modification (ABM)task - the Detection Engagement and Savoring Positivity (DESP) task - on attentional biases.The DESP is innovative in that it involves a procedure of savoring the positivity of variouspictures.Methods: Participants were randomly assigned to the DESP or to a placebo control condition(experiment 1; n = 38) or a condition controlling for savoring (experiment 2; n = 54) in a prepost/training experimental design. During one week, the participants completed the DESP orthe control task once a day between three and six times. We assessed the effects of the DESPtask on various attentional biases (i.e. positive, negative and threat) by computing dwell timefrom an eye-tracking technology before and after the training, and also one week after thepost-training session in experiment 2.Results: In both experiments, the attentional bias toward positive stimuli between the pre- andthe post-training increased significantly more in the DESP task condition than in the controlconditions. Negative and threat attentional biases were not significantly affected by theexperimental manipulations. Experiment 2 revealed that the DESP task – including thesavoring instruction - increased significantly more the positive attentional bias than a taskexcluding this step and that this effect remained significant one week after the post-trainingsession.Limitations: Our samples were mainly composed of women participants. This preventsgeneralization of the findings.Conclusions: The DESP task offers promising perspectives for sustainably improvingattention to positive information

Spatiotemporal matrix image formation for programmable ultrasound scanners

International audienceAs programmable ultrasound scanners become more common in research laboratories, it is increasingly important to develop robust software-based image formation algorithms that can be obtained in a straightforward fashion for different types of probes and sequences with a small risk of error during implementation. In this work, we argue that as the computational power keeps increasing, it is becoming practical to directly implement an approximation to the matrix operator linking reflector point targets to the corresponding radiofrequency signals via thoroughly validated and widely available simulations software. Once such a spatiotemporal forward-problem matrix is constructed, standard and thus highly optimized inversion procedures can be leveraged to achieve very high quality images in real time. Specifically, we show that spatiotemporal matrix image formation produces images of similar or enhanced quality when compared against standard delay-and-sum approaches in phantoms and in vivo, and show that this approach can be used to form images even when using non-conventional probe designs for which adapted image formation algorithms are not readily available

Mapping Biological Current Densities With Ultrafast Acoustoelectric Imaging: Application to the Beating Rat Heart

Ultrafast acoustoelectric imaging (UAI) is a novel method for the mapping of biological current densities, which may improve the diagnosis and monitoring of cardiac activation diseases such as arrhythmias. This paper evaluates the feasibility of performing UAI in beating rat hearts. A previously described system based on a 256-channel ultrasound research platform fitted with a 5-MHz linear array was used for simultaneous UAI, ultrafast B-mode, and electrocardiogram (ECG) recordings. In this paper, rat hearts (n = 4) were retroperfused within a Langendorff isolated heart system. A pair of Ag/Cl electrodes were positioned on the epicardium to simultaneously record ECG and UAI signals for imaging frame rates of up to 1000 Hz and a mechanical index of 1.3. To account for the potential effect of motion on the UAI maps, acquisitions for n = 3 hearts were performed with and without suppression of the mechanical contraction using 2,3-butanedione monoxime. Current densities were detected for all four rats in the region of the atrio-ventricular node, with an average contrast-to-noise ratios of 12. The UAI signals' frequency matched the sinus rhythm, even without mechanical contraction, suggesting that the signals measured correspond to physiological electrical activation. UAI signals appeared at the apex and within the ventricular walls with a delay estimated at 29 ms. Finally, the signals from different electrode positions along the myocardium wall showed the possibility of mapping the electrical activation throughout the heart. These results show the potential of UAI for cardiac activation mapping in vivo and in real time