From laser cooling to aging: a unified Levy flight description

Intriguing phenomena such as subrecoil laser cooling of atoms, or aging phenomenon in glasses, have in common that the systems considered do not reach a steady-state during the experiments, although the experimental time scales are very large compared to the microscopic ones. We revisit some standard models describing these phenomena, and reformulate them in a unified framework in terms of lifetimes of the microscopic states of the system. A universal dynamical mechanism emerges, leading to a generic time-dependent distribution of lifetimes, independently of the physical situation considered.Comment: 8 pages, 2 figures; accepted for publication in American Journal of Physic

Fluctuation-Dissipation Relations and statistical temperatures in a turbulent von K\'arm\'an flow

We experimentally characterize the fluctuations of the non-homogeneous non-isotropic turbulence in an axisymmetric von K\'arm\'an flow. We show that these fluctuations satisfy relations analogous to classical Fluctuation-Dissipation Relations (FDRs) in statistical mechanics. We use these relations to measure statistical temperatures of turbulence. The values of these temperatures are found to be dependent on the considered observable as already evidenced in other far from equilibrium systems.Comment: four pages 2 figures one tabl

Faire de l'histoire : conclusion

Les articles réunis dans ce bulletin ont permis d’entrevoir la diversité des profils d’historiens et des pratiques historiques au Moyen Âge. Les différentes contributions ont tout d’abord mis en évidence l’intérêt d’analyser la matérialité des œuvres historiques. Celle-ci permet, comme l’a souligné Antoine Brix, d’appréhender non seulement la diffusion, mais aussi la réception de ces œuvres, d’établir quels sont leurs lectorats – qui peuvent être extrêmement divers – et de déterminer quelles..

Faire de l'histoire : éléments bibliographiques

Cette bibliographie n’a pas vocation à l’exhaustivité ; elle reprend essentiellement les références utilisées dans le numéro. Généralités Guenée, Bernard, « Y a-t-il une historiographie médiévale ? », Revue historique, vol. 258, 1977, p. 261–275. –, Histoire et culture historique dans l’Occident médiéval, Paris, Aubier, 2011 [1980]. L’Historiographie médiévale en Europe. Actes du colloque organisé par la Fondation Européenne de la Science au Centre de Recherches Historiques et Juridiques de l..

Faire de l'histoire : introduction

Depuis l’ouvrage pionnier de Bernard Guenée, Histoire et culture historique dans l’Occident médiéval, les travaux sur l’historiographie médiévale se sont multipliés et ont permis de réhabiliter le travail des historiens de cette période qui n’étaient pas les chroniqueurs naïfs qu’on a longtemps dépeints. Au Moyen Âge, l’histoire n’est ni une science, ni une discipline à part entière. Elle ne figure pas parmi les sept arts libéraux étudiés à l’université et n’est enseignée qu’en tant que disci..

Faire de l'histoire : éléments bibliographiques

Cette bibliographie n’a pas vocation à l’exhaustivité ; elle reprend essentiellement les références utilisées dans le numéro. Généralités Guenée, Bernard, « Y a-t-il une historiographie médiévale ? », Revue historique, vol. 258, 1977, p. 261–275. –, Histoire et culture historique dans l’Occident médiéval, Paris, Aubier, 2011 [1980]. L’Historiographie médiévale en Europe. Actes du colloque organisé par la Fondation Européenne de la Science au Centre de Recherches Historiques et Juridiques de l..

Faire de l'histoire : conclusion

Les articles réunis dans ce bulletin ont permis d’entrevoir la diversité des profils d’historiens et des pratiques historiques au Moyen Âge. Les différentes contributions ont tout d’abord mis en évidence l’intérêt d’analyser la matérialité des œuvres historiques. Celle-ci permet, comme l’a souligné Antoine Brix, d’appréhender non seulement la diffusion, mais aussi la réception de ces œuvres, d’établir quels sont leurs lectorats – qui peuvent être extrêmement divers – et de déterminer quelles..

Bacterial toxins modifying the actin cytoskeleton

Numerous bacterial toxins recognize the actin cytoskeleton as a target. The clostridial binary toxins (Iota and C2 families) ADP-ribosylate the actin monomers causing the dissociation of the actin filaments. The large clostridial toxins from Clostridium difficile, Clostridium sordellii and Clostridium novyi inactivate, by glucosylation, proteins from the Rho family that regulate actin polymerization. In contrast, the cytotoxic necrotic factor from Escherichia coli activates Rho by deamidation and increases the formation of actin filaments. The enterotoxin of Bacteroides fragilis is a protease specific for E-cadherin and it promotes the reorganization of the actin cytoskeleton. The bacterial toxins that modify the actin cytoskeleton induce various cell disfunctions including changes in cell barrier permeability and disruption of intercellular junctions

Digital Investigation of IoT Devices in the Criminal Scene

The Internet of Things (IoT) is everywhere around us. Smart communicating objects are offering the digitalization of lives. They create new opportunities within criminal investigations. In recent years, the scientific community sought to develop a common digital framework and methodology adapted to IoT-based infrastructure. However, the difficulty in exploiting the IoT lies in the heterogeneous nature of the devices, the lack of standards and the complex architecture. Although digital forensics are considered and adopted in IoT investigations, this work only focuses on the collection. The identification phase is quite unexplored. It addresses the challenges of locating hidden devices and finding the best evidence to be collected. The matter of facts is the traditional method of digital forensics does not fully fit the IoT environment. Furthermore, the investigator can no longer consider a connected object as a single device, but as an interconnected whole one, anchored in a cross-disciplinary environment. This paper presents the methodology for identifying and classifying connected objects in search of the best evidence to be collected. It offers techniques for detecting and locating the appropriate equipment. Based on frequency mapping and interactions, it transfers the concept of "fingerprinting" into the field of crime scene. It focuses on the technical and data criteria to successfully select the relevant IoT devices. It gives a general classiffication as well as the limits of such an approach. It shows the collection of digital evidence by focusing on pertinent information from the Internet of Things

Averaging rheological quantities in descriptions of soft glassy materials

Many mean-field models have been introduced to describe the mechanical behavior of glassy materials. They often rely on averages performed over distributions of elements or states. We here underline that averaging is a more intricate procedure in mechanics than in more classical situations such as phase transitions in magnetic systems. This leads us to modify the predictions of the recently proposed SGR model for soft glassy materials, for which we suggest that the viscosity should diverge at the glass transition temperature $T_g$ with an exponential form $\eta \sim \exp(\frac{A}{T-T_g})$.Comment: 4 pages, Latex, 1 eps figur