Integrating Simulink Models into the Model Checker Cosmos

International audienceWe present an implementation for Simulink model executions in the statistical model-checker Cosmos. We take profit of this implementation for hybrid modeling and simulations combining Petri nets and Simulink models.Nous présentons une implémentation pour l'exécution de modèles Simulink dans le model-checker Cosmos. Cette implémentation est ensuite utilisée pour la simulation de modèles hybrides, combinant des réseaux de Petri et des modèles Simulink

Fuchsian convex bodies: basics of Brunn--Minkowski theory

The hyperbolic space \H^d can be defined as a pseudo-sphere in the $(d+1)$ Minkowski space-time. In this paper, a Fuchsian group $\Gamma$ is a group of linear isometries of the Minkowski space such that \H^d/\Gamma is a compact manifold. We introduce Fuchsian convex bodies, which are closed convex sets in Minkowski space, globally invariant for the action of a Fuchsian group. A volume can be associated to each Fuchsian convex body, and, if the group is fixed, Minkowski addition behaves well. Then Fuchsian convex bodies can be studied in the same manner as convex bodies of Euclidean space in the classical Brunn--Minkowski theory. For example, support functions can be defined, as functions on a compact hyperbolic manifold instead of the sphere. The main result is the convexity of the associated volume (it is log concave in the classical setting). This implies analogs of Alexandrov--Fenchel and Brunn--Minkowski inequalities. Here the inequalities are reversed

Spatially variable fault friction derived from dynamic modeling of aseismic afterslip due to the 2004 Parkfield earthquake

We investigate fault friction from dynamic modeling of fault slip prior to and following the Mw 6.0 earthquake which ruptured the Parkfield segment of the San Andreas Fault in 2004. The dynamic modeling assumes a purely rate-strengthening friction law, with a logarithmic dependency on sliding rate: μ=μ *+a-blnvv*. The initial state of stress is explicitly taken into account, and afterslip is triggered by the stress change induced by the earthquake source model given a priori. We consider different initial stress states and two coseismic models, and invert for the other model parameters using a nonlinear inversion scheme. The model parameters include the reference friction μ*, the friction rate dependency characterized by the quantity a-b, assumed to be either uniform or depth dependent. The model parameters are determined from fitting the transient postseismic geodetic signal measured at continuous GPS stations. Our study provides a view of frictional properties at the kilometers scale over the 0-15 km depth illuminated by the coseismic stress change induced by the Parkfield earthquake. The reference friction is estimated to be between 0.1 and 0.5. With independent a priori constraints on the amplitude of differential stress, the range of possible values narrows down to 0.1-0.17. The friction rate coefficient a-b is estimated to be � 10- 3 - 10- 2 with a hint that it increases upward from about 1-3 � 10-3 at 3-7 km depth to about 4-7 � 10-3 at 0-1 km depth. It is remarkable that our results are consistent with frictional properties measured on rock samples recovered from the fault zone thanks to the San Andreas Fault Observatory at Depth experiment. ©2013. American Geophysical Union. All Rights Reserved

Particle Physics Explanations for Ultra High Energy Cosmic Ray Events

The origin of cosmic ray events with E \gsim 10^{11} GeV remains mysterious. In this talk I briefly summarize several proposed particle physics explanations: a breakdown of Lorentz invariance, the ``$Z-$burst'' scenario, new hadrons with masses of several GeV as primaries, and magnetic monopoles with mass below $10^{10}$ GeV as primaries. I then describe in a little more detail the idea that these events are due to the decays of very massive, long--lived exotic particles.Comment: Invited plenary talk at PASCOS03, Mumbai, India, January 2003; 13 pages, 1 figur

Sudakov Electroweak effects in transversely polarized beams

We study Standard Model electroweak radiative corrections for fully inclusive observables with polarized fermionic beams. Our calculations are relevant in view of the possibility for Next Generation Linear colliders of having transversely and/or longitudinally polarized beams. The case of initial transverse polarization is particularly interesting because of the interplay of infrared/collinear logarithms of different origins, related both to the nonabelian SU(2) and abelian U(1) sectors. The Standard model effects turn out to be in the 10% range at the TeV scale, therefore particularly relevant in order to disentangle possible New Physics effects.Comment: 5 pages,4 figure

Notes on a paper of Mess

These notes are a companion to the article "Lorentz spacetimes of constant curvature" by Geoffrey Mess, which was first written in 1990 but never published. Mess' paper will appear together with these notes in a forthcoming issue of Geometriae Dedicata.Comment: 26 page

From communities of Practice to Epistemic Communities: Health Mobilizations on the Internet

International audienceThis paper describes the emergence of new activist groups in the health sector, spinning off from internet discussion groups. In the first part, it shows how self-help discussion groups can be considered as communities of practice in which, partly thanks to the Internet media, collective learning activities result in the constitution of experiencial knowledge, the appropriation of exogenous sources of knowledge, including medical knoweldge and the articulation of these different sources of knowledge in some lay expertise. In the second part, it describes how activist groups might emerge from these discussion groups and develop specific modes of action drawing upon the forms of expertise constituted through the Internet groups. Activists groups together with self-help groups might form epistemic communities (Haas 1992), i.e. groups of experts engaged in a policy enterprise in which knowledge plays a major role : in the confrontation of health activists with professionals, the capacity to translate political claims into the langage of science appears as a condition to be (even) heard and be taken into consideration

Children with facial paralysis due to Moebius syndrome exhibit reduced autonomic modulation during emotion processing

Background: Facial mimicry is crucial in the recognition of others' emotional state. Thus, the observation of others' facial expressions activates the same neural representation of that affective state in the observer, along with related autonomic and somatic responses. What happens, therefore, when someone cannot mimic others' facial expressions? Methods: We investigated whether psychophysiological emotional responses to others' facial expressions were impaired in 13 children (9 years) with Moebius syndrome (MBS), an extremely rare neurological disorder (1/250,000 live births) characterized by congenital facial paralysis. We inspected autonomic responses and vagal regulation through facial cutaneous thermal variations and by the computation of respiratory sinus arrhythmia (RSA). These parameters provide measures of emotional arousal and show the autonomic adaptation to others' social cues. Physiological responses in children with MBS were recorded during dynamic facial expression observation and were compared to those of a control group (16 non-affected children, 9 years). Results: There were significant group effects on thermal patterns and RSA, with lower values in children with MBS. We also observed a mild deficit in emotion recognition in these patients. Conclusion: Results support "embodied" theory, whereby the congenital inability to produce facial expressions induces alterations in the processing of facial expression of emotions. Such alterations may constitute a risk for emotion dysregulation