Effects of image and verbal generation on false recalls and false recognition

International audienc

Linguistic analysis of laser speckle contrast images recorded at rest and during biological zero: comparison with laser Doppler flowmetry data

Laser speckle contrast imaging (LSCI) is a newly commercialized imaging modality to monitor microvascular blood flow. Contrary to the well-known laser Doppler flowmetry (LDF), LSCI has the advantage of giving a full-field image of surface blood flow using simple instrumentation. However, laser speckle contrast images are not fully understood yet and their link with LDF signals still has to be studied. To quantify the similarity between LSCI and LDF symbolic sequences, we propose to use, for the first time, the index adapted from linguistic analysis and information theory proposed by Yang For this purpose, LSCI and LDF data were recorded simultaneously on the forearm of healthy subjects, at rest and during a vascular occlusion (biological zero). We show that there are different dynamical patterns for LSCI and LDF data, and the distances between these patterns differ through the space scales explored. Moreover, our results suggest that these different dynamical patterns could be linked to blood flow. The quantitative metric used herein therefore provides new information on LSCI and brings knowledge on links between LSCI and LDF

Caractérisation du comportement non-stationnaire du système d’admission d’air d’un moteur à combustion interne. Incidence sur le remplissage.

The aim of this PhD thesis is to develop a new characterization method of unsteady flow in internal combustion engine intake manifold. Then, an experimental setup was developed in order to generate pressure waves from a fast change in flow. The measurement method coupled to this device allows to obtain the air intake system impedance. This method is able to produce very high pressure oscillations which are similar to those encountered in an engine.On the other hand, an unsteady flow modelisation of intake pipes was developed to assess the impact of the manifold geometry on the engine volumetric efficiency. The model parameters are then identified for each intake system by experimental characterization results from the test bench. Finally, the whole process is evaluated on a one cylinder engine test bench. Furthermore, a study of a line for admission of a multi-cylinder engine manifold was conducted.Ce travail est consacré au développement d’une méthodologie expérimentale de caractérisation des écoulements non-stationnaire dans les systèmes d’admission d’air des moteurs à combustion interne. Un dispositif expérimental a alors été mis au point dans le but de générer une onde de pression à partir d’une variation brutale de débit. La méthode de mesure associée permet de fournir une mesure de l’impédance d’un circuit d’admission. Cette méthode qui atteint des niveaux de pression comparables à ceux observés dans les moteurs permet d’analyser les phénomènes de propagations et de réflexions des ondes de pression.D’autre part, un modèle de comportement des écoulements non-stationnaires en conduit a été développé afin d’évaluer l’incidence de géométrie d’admission sur le rendement volumétrique d’un moteur. Les paramètres de ce modèle sont alors identifiés pour chaque système d’admission à partir des essais expérimentaux du banc de caractérisation. L’ensemble de la démarche est finalement validé sur un banc d’essai monocylindre qui a été complété par l’étude d’une ligne d’admission d’un moteur multicylindres

Excellent inter- and intra-observer reproducibility of microvascular tests using laser speckle contrast imaging.

Post-occlusive reactive hyperaemia (PORH) and vasodilation induced by acetylcholine (ACh) iontophoresis are tests of endothelial function that can be studied with laser speckle contrast imaging (LSCI). LSCI has the advantage of having good temporal and spatial resolutions but can lead to a high amount of data when several minutes of recordings are needed. Parameters of PORH and ACh iontophoresis vasodilation are therefore often determined by several observers or by the same observer on different days. Nevertheless, inter- and intra-observer reproducibility for the determination of such parameters has not been studied yet. We analyzed inter-observer and intra-observer reproducibility of baseline, peak and plateau determination for the two microvascular tests. Ten recordings of both PORH and ACh iontophoresis have been analyzed by two blinded trained observers. For peak determination, inter-observer coefficient of variation (CV) was 4.7% and 3.0% for PORH and ACh respectively. Intra-observer reproducibility expressed in CV ranges from 2.4% to 5.4% for PORH-peak and ACh-peak. CVs for peak determination are better than for baseline or plateau determination for both microvascular tests. This suggests that when microvascular vasodilations are reported, the data segments measured have to be noted. Finally microvascular tests using LSCI have an excellent intra- and inter-observer reproducibility

An On-Demand Coherent Single Electron Source

We report on the electron analog of the single photon gun. On demand single electron injection in a quantum conductor was obtained using a quantum dot connected to the conductor via a tunnel barrier. Electron emission is triggered by application of a potential step which compensates the dot charging energy. Depending on the barrier transparency the quantum emission time ranges from 0.1 to 10 nanoseconds. The single electron source should prove useful for the implementation of quantum bits in ballistic conductors. Additionally periodic sequences of single electron emission and absorption generate a quantized AC-current