Walks of bubbles on a hot wire in a liquid bath

When a horizontal resistive wire is heated up to the boiling point in a subcooled liquid bath, some vapor bubbles nucleate on its surface. Traditional nucleate boiling theory predicts that bubbles generated from active nucleate sites, grow up and depart from the heating surface due to buoyancy and inertia. However, we observed here a different behavior: the bubbles slide along the heated wire. In this situation, unexpected regimes are observed; from the simple sliding motion to bubble clustering. We noticed that bubbles could rapidly change their moving direction and may also interact. Finally, we propose an interpretation for both the attraction between the bubbles and the wire and for the motion of the bubbles on the wire in term of Marangoni effects

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

Déploiement d'ordonnanceurs de processus spécifiques dans un système d'exploitation généraliste

L'environnement Bossa permet la conception d'ordonnanceurs spécifiques offrant ainsi une gestion précise de la ressource processeur au sein d'un système d'exploitation généraliste. Toutefois, le déploiement conjoint d'une application et de son ordonnanceur suscite des problèmes liés à la réservation de la ressource processeur. Dans cet article, nous étudions les problèmes dus à ce type de déploiement et proposons quelques solutions. En particulier, nous proposons d'établir des contrats de qualité de service et des mécanismes de reconfiguration de la hiérarchie d'ordonnanceurs. –––––Bossa is a framework to develop new processes schedulers in commodity operating systems. Although Bossa enables fine-grained management of the processor through new scheduling policies, deploying an application with its own scheduler raises some problems. In this paper we study the problems caused when deploying an application and its scheduler and to adresse these, we propose to establish Quality of Service contracts and mechanisms to reconfigure the scheduler hierarchy

Tightrope dancer bubbles

International audienc

Between inertia and viscous effects: Sliding bubbles beneath an inclined plane

The ascent motion of an air bubble beneath an inclined plane is experimentally studied. The effects of the surrounding liquid viscosity and surface tension, the bubble radius and the tilt angle are investigated. A dynamical model is proposed. It opposes the buoyant driving force to the hydrodynamical pressure arising from the bubble motion and the capillary meniscus generated in front of the bubble in order to create a lubrication film between the bubble and the plate. This model is compared to experimental data and discussed.SUPERCOO