BOURET , Yann

We investigate several distribution-free dependence detection procedures, all based on a shuffling of the trials, from a statistical point of view. The mathematical justification of such procedures lies in the bootstrap principle and its approximation properties. In particular, we show that such a shuffling has mainly to be done on centered...

Motivated by a neuroscience question about synchrony detection in spike train analysis, we deal with the independence testing problem for point processes. We introduce non-parametric test statistics, which are rescaled general $U$-statistics, whose corresponding critical values are constructed from bootstrap and randomization/permutation...

International audience

We experimentally investigate the reactivity of Leidenfrost droplets with their supporting substrates. Several organic liquids are put into contact with a copper substrate heated above their Leidenfrost temperature. As the liquid evaporates, the gaseous flow cleans the superficial copper oxide formed at the substrate surface and the reaction...

National audience

Amperometry with ultramicroelectrodes is nowadays a routine technique to investigate neurotransmitter secretion by vesicular exocytosis at the single-cell level. This electroanalytical tool allows one to understand many aspects of the vesicular release in terms of mechanisms. However, the electrochemical detection relies on the oxidation of...

International audience

Background: Statistical models that predict neuron spike occurrence from the earlier spiking activity of the whole recorded network are promising tools to reconstruct functional connectivity graphs. Some of the previously used methods were in the general statistical framework of the multivariate Hawkes processes but they often required huge...

Cell volume, together with membrane potential and intracellular hydrogen ion concentration, is an essential biophysical parameter for normal cellular activity. Cell volumes can be altered by osmotically active compounds and extracellular tonicity.In this study, a simple mathematical model of osmotically induced cell swelling and shrinking is...

A robotic fish is used to test the validity of a simplification made in the context of fish locomotion. With this artificial aquatic swimmer, we verify that the momentum equation results from a simple balance between a thrust and a drag that can be treated independently in the small amplitude regime. The thrust produced by the flexible robot is...

We investigate the nucleation of cavitation bubbles in a conned Lennard-Jones uid submitted to negative pressures in a cubic enclosure. We perform molecular dynamics (MD) simulations with tunable interatomic potentials that enable to control the wettability of the solid walls by the liquid, i.e its contact angle. For a given temperature and...

International audience

Plateau borders are liquid microchannels located at the contact between three bubbles in liquid foams. They are stable, deformable and can be thought of as quasi-1D model systems to study surface waves in fluid dynamics. We show that the burst of a bubble trapped in a PB produces local constrictions which travel along the liquid channel at...

In flows where the ratio of inertia to gravity varies strongly, large variations in the fluid thickness appear and hydraulic jumps arise, as depicted by Rayleigh. We report a new family of hydraulic jumps, where the capillary effects dominate the gravitational acceleration. The Bond number – which measures the importance of gravitational body...

We report an experimental study of bubble dynamics in a non-Newtonian fluid subjected to a pressure decrease. The fluid is a hydrogel, composed of water and a synthetic clay, prepared and sandwiched between two glass plates in a Hele-Shaw geometry. The rheological properties of the material can be tuned by the clay concentration. As the imposed...

In previous works, we have introduced analternative perturbation scheme to find approximate solutions of the spectralproblem for the rotation-vibration molecular Hamiltonian.An important feature of our approach is that the zero order Hamiltonian is the direct product of a purely vibrational Hamiltonianwith the identity on the rotational...

International audience

We study transient flows of liquid along a single Plateau border (PB). In opposition with a common belief, we show that a fast, inertial regime of flow, very little dependent on the fluid viscosity, can be encountered in the high surface mobility limit. This newly observed regime evolves into the regular viscous regime after a critical distance...

International audience

We study a single, centimeter-long, horizontal, Plateau border (PB). We perturb it locally by dropping a droplet of liquid, which coalesces with the PB, and we follow the dynamics of the subsequent liquid imbibition. Because the PB is horizontal, gravity effects are negligible and the liquid flow is driven by capillarity only. We find that an...

We report a capillary-inertial flow in an unbounded liquid microchannel -a Plateau border in a liquid foam- and discuss its relevance for foam drainage. In contrast to the case of jets of cylindrical geometry, which are susceptible to the Rayleigh-Plateau instability, in this channel any liquid perturbation is dispersed instead of amplified....

International audience

International audience

Our experimental configuration deals with an unique Plateau border positioned horizontally. The latter is supplied externally with a droplet of the same liquid, dropped from above. The droplet coalesces with the Plateau border. We study various liquids with different bulk and surface viscosities and surface tension, and Plateau borders of...