Swelling of phospholipid floating bilayers: the effect of chain length

The equilibrium distance between two lipid bilayers stable in bulk water and in proximity of a substrate was investigated. Samples consisted of a homogeneous lipid bilayer, floating near an identical bilayer deposited on the hydrophilic surface of a silicon single crystal. Lipids were saturated di-acyl phosphocholines, with the number of carbon atoms per chain, n, varying from 16 to 20. The average and r.m.s. positions of the floating bilayer were determined by means of neutron specular reflectivity. Samples were prepared at room temperature (i.e. with the lipids in the gel phase) and measurements performed at various temperatures so that the whole region of transition from gel to fluid phase was explored. Data have been interpreted in terms of competition between the interbilayer potential and membrane fluctuations and used to estimate the bending rigidity of the bilayer

Analyzing behavioral data for refining cognitive models of operator

International audienceWe present a methodology and a tool for analyzing the activity of an operator interacting with a complex technical device. The goal is of refining cognitive models of the operator by relating them to patterns of behavior in real situations. The activity is observed to be modeled as a trace having a graph structure. The trace is transformed according to a "use model" in order to become meaningful in the context of modeling theories. Our "Trace Based System" thus gathers both a representation of the activity and of the analyst's expertise for facilitating the discovery of knowledge in the field of cognitive psychology. The approach is illustrated by its application for car driver cognitive modeling

Driver behaviour modelling and cognitive engineering tools development in order to assess driver sitation awareness

International audienceOur global objective is to define a framework for car driving behaviour analysis in order to assess driver's situation awareness. We present models, methods and software tools inspired from the "Experience Based Reasoning" theory coming from the field of artificial intelligence. It allows a construction of a representation of the driving activity including data collected in real driving situations as well as interpretations made on the driver's mental model of the situation, and permits a refinement of psychological theories

Modélisation de la microstructure des grains dans le silicium multicristallin pour le photovoltaïque

L'objectif de ce travail est d'approfondir et de mieux comprendre les mécanismes responsables de la formation et de la croissance de la structure des grains dans le silicium multicristallin pour des applications photovoltaïques. Lors de la solidification du silicium multicristallin, la sélection des grains, le contrôle de la distribution de leur taille et leur direction de croissance sont des paramètres importants pour obtenir un matériau de bonne qualité et homogène. Ces paramètres influencent directement le rendement de conversion des cellules photovoltaïques, au travers de la capture et de la recombinaison des porteurs de charges et des interactions avec les impuretés. La structure de grains dans le silicium photovoltaïque évolue au cours de la solidification : des grains vont disparaître, d'autres vont apparaître, d'autres vont grossir pour donner au final une structure composée de gros grains, de petits grains dénommés grits', de joints de grains, et de macles. Il est donc important de comprendre les relations entre les différents paramètres du procédé industriel et leur influence sur les phénomènes physico-chimiques qui se produisent lors de la croissance afin de pouvoir influer sur la structure de grains dans le silicium, et de prévoir ses propriétés. Dans une première étape, nous avons établi un modèle de développement des grains basé sur le type de croissance (facettée, rugueuse ou mixte), la cinétique de ces divers types de croissances, le phénomène de maclage et la sélection des grains, dont nous montrons qu'ils sont, avec la germination initiale, à l'origine de la taille et de la structure des grains. Ensuite, nous proposons une approche de modélisation numérique de l'évolution de la structure des grains au cours de la solidification. Cette méthode se base sur l'analyse dynamique bidimensionnelle du joint de grains au niveau de la ligne triple grain-grain-liquide (rugueuse, facettée) tout en prenant en compte les phénomènes produits à l'échelle macroscopique (le champ de température local) et microscopique (la cinétique des grains). Le modèle résulte du couplage thermique et des mécanismes cinétiques de croissance. Nous avons donc développé un modèle numérique de croissance des grains en 2 dimensions et nous l'avons introduit dans le code 2D-MiMSiS qui se déroule en 2 étapes : Premièrement, le calcul en régime transitoire de la solidification macroscopique d'un lingot de silicium nous permet d'obtenir le champ thermique dans le lingot et la position précise de l'interface solide-liquide à différents instants ainsi que sa vitesse, son orientation (sa forme) et les gradients de température dans le liquide et le solide. Deuxièmement, la modélisation de la croissance est basée sur la description géométrique des joints de grains qui dépend de la cinétique des grains qui les bordent. Elle suit des critères dépendants de la morphologie (rugueuse ou facettée) de l'interface. Elle s appuie sur le réseau d'isothermes du calcul thermique sans l'influencer dans un premier temps. Un des objectifs de ce modèle est de faire varier différents paramètres du procédé et d'en mesurer l'impact sur la structure cristalline finale. Des résultats de calculs 2D sont présentés et discutés par rapport à l'expérience.The objective of this work is to explore and better understand the mechanisms responsible for the formation and growth of the grain structure in polycrystalline silicon for photovoltaic applications. During the solidification of polycrystalline silicon for the selection of the grain, control the distribution of their size and direction of growth are important parameters to obtain a material of good quality and homogeneous. These parameters directly influence the conversion efficiency of solar cells, through the capture and recombination of charge carriers and interactions with impurities. Grain structure in silicon photovoltaic evolves during solidification: Grain will disappear, others will appear, others will grow to give the final structure composed of large grains, small grains called 'grits' grain boundaries and twins. It is therefore important to understand the relationship between the parameters of the industrial process, the physico-chemical phenomena that occur during the growth and structure of grains in the silicon to predict its properties. In a first step, we established a model of development based on the grain growth type (faceted, rough or mixed), the kinetics of the various growths, the phenomenon of twinning and the selection of grains, we show that they are, with the initial germination, originally of the size and structure of the grains. Then, we propose an approach to numerical modeling of the evolution of lala grain structure during solidification. This method is based on the two-dimensional dynamic analysis of the grain boundary at the triple line grain-grain-liquid (rough, faceted) taking into account the phenomena produced at the macroscopic scale (the local temperature field) and microscopic (kinetic grain). The resulting model of the thermal coupling mechanisms and growth kinetics. We have developed a numerical model of grain growth in two dimensions, and we have introduced in the 2D-code MiMSiS which takes place in two steps: First, the calculation of transient macroscopic solidification of an ingot of silicon allows us to obtain the temperature field in the ingot and the precise position of the solid-liquid interface at different times as well as its speed, direction ( form) and the thermal gradients in the liquid and the solid. Second, the growth model is based on the geometrical description of grain boundary which depends on the kinetics of grain that border. It follows dependent criteria of the rough morphology or faceted interface. It relies on a network of insulated thermal calculation without influence in the first place. One objective of this model is to vary the process parameters and to measure their impact on the final crystalline structure. 2D calculation results are presented and discussed in relation to the experience.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Acceptability and Acceptance of Autonomous Mobility on Demand: The Impact of an Immersive Experience

Autonomous vehicles have the potential to fundamentally change existing transportation systems. Beyond legal concerns, these societal evolutions will critically depend on user acceptance. As an emerging mode of public transportation [7], Autonomous mobility on demand (AMoD) is of particular interest in this context. The aim of the present study is to identify the main components of acceptability (before first use) and acceptance (after first use) of AMoD, following a user experience (UX) framework. To address this goal, we conducted three workshops (N=14) involving open discussions and a ride in an experimental autonomous shuttle. Using a mixed-methods approach, we measured pre-immersion acceptability before immersing the participants in an on-demand transport scenario, and eventually measured post-immersion acceptance of AMoD. Results show that participants were reassured about safety concerns, however they perceived the AMoD experience as ineffective. Our findings highlight key factors to be taken into account when designing AMoD experiences

Proteomic profile determination of autosomal aneuploidies by mass spectrometry on amniotic fluids

<p>Abstract</p> <p>Background</p> <p>Prenatal diagnosis of chromosomal abnormalities by cytogenetic analysis is time-consuming, expensive, and requires highly qualified technicians. Rapid diagnosis of aneuploidies followed by reassurance of women with normal results can be performed by molecular analysis of uncultured foetal cells. In the present study, we developed a proteomic fingerprinting approach coupled with a statistical classification method to improve diagnosis of aneuploidies, including trisomies 13, 18, and 21, in amniotic fluid samples.</p> <p>Results</p> <p>The proteomic spectra obtained from 52 pregnant women were compiled, normalized, and mass peaks with mass-to-charge ratios between 2.5 and 50 kDa identified. Peak information was combined together and analysed using univariate statistics. Among the 208 expressed protein peaks, 40 differed significantly between aneuploid and non aneuploid samples, with AUC diagnostic values ranging from 0.71 to 0.91. Hierarchical clustering, principal component analysis and support vector machine (SVM) analysis were performed. Two class predictor models were defined from the training set, which resulted in a prediction accuracy of 92.3% and 96.43%, respectively. Using an external and independent validation set, diagnostic accuracies were maintained at 87.5% and 91.67%, respectively.</p> <p>Conclusion</p> <p>This pilot study demonstrates the potential interest of protein expression signature in the identification of new potential biological markers that might be helpful for the rapid clinical management of high-risk pregnancies.</p

Abstract: un outil et une méthodologie pour analyser une activité humaine médiée par un artefact technique complexe

National audienceNous présentons une méthodologie et un outil pour analyser l'activité d'un opérateur humain en interaction avec un dispositif technique complexe. L'activité est observée pour être modélisée sous la forme d'une trace ayant une structure de graphe. La trace collectée est constituée initialement d'une succession de descripteurs d'événements, liés par une relation de séquentialité. Elle est ensuite enri-chie selon un modèle d'utilisation pour construire une représentation de l'activité à différents ni-veaux d'abstraction. Cela permet de retrouver des signatures de schémas mentaux mis en ½uvre par l'opérateur. Cette approche est utilisée pour la modélisation cognitive du conducteur automobile

DECOMOBIL Human Centred Design for Safety Critical Transport Systems. Deliverable 3.6

The scientific seminar on 'Human Centred Design for Safety Critical Transport Systems' organized in the framework of DECOMOBIL has been held the 8th of September 2014 in Lisbon, Portugal, hosted by ADI/ISG. The aims of the event were to present the scientific problematic related to the safety of the complex transport systems and the increasing importance of human-­centred design, with a specific focus on Resilience Engineering concept, a new approach to safety management in highly complex systems, on knowledge and experience from other transport modes, particularly aviation and space, in which automation processes are accompanied by an increase in safety and security and on the safety of vulnerable road users and its potential link to automation. To close the workshop, an analysis of safety vs. ecomobility highlighting research priorities has been presented to the audience. As a special speaker, Myriam Coulon-­Cantuer, EC Project Officer of the DG Connect, presented the view of the EC on the future research challenges for ICT and transport. Document type: Repor

Large deviations of lattice Hamiltonian dynamics coupled to stochastic thermostats

We discuss the Donsker-Varadhan theory of large deviations in the framework of Hamiltonian systems thermostated by a Gaussian stochastic coupling. We derive a general formula for the Donsker-Varadhan large deviation functional for dynamics which satisfy natural properties under time reversal. Next, we discuss the characterization of the stationary state as the solution of a variational principle and its relation to the minimum entropy production principle. Finally, we compute the large deviation functional of the current in the case of a harmonic chain thermostated by a Gaussian stochastic coupling.Comment: Revised version, published in Journal of Statistical Physic

Etude numérique du remplissage 3D en fonderie

Ce travail porte sur la simulation numérique par éléments finis, d'écoulements tridimensionnels incompressibles à surface libre instationnaires. L'application industrielle visée est l'étude de la phase de remplissage des procédés de fonderie.Il consiste principalement en l'adaptation du logiciel REM3D® qui est un logiciel initialement dédié à l'injection des polymères. Les méthodes présentes dans ce code permettent de résoudre les écoulements visqueux à surface libre, dans une approche multidomaine. La résolution directe d'un problème de Navier-Stokes est effectuée en introduisant, dans le solveur initial, les termes de gravité et d'inertie. Ces derniers sont exprimés à l'aide d'une approximation P1 par morceaux de la vitesse, et de la vitesse moyenne par élément, qui est P0 par morceaux : les termes d'advection sont exprimés par une méthode Galerkin discontinu standard. Le problème en vitesse/pression est stabilisé par condensation de bulle. Cette méthode a été testée sur plusieurs cas académiques, pour des écoulements stationnaires et instationnaires, avec suivi de la surface libre. Enfin, afin de pouvoir simuler les écoulements rencontrés en fonderie, des conditions de contact glissant ont été introduites. Un algorithme original de construction de normales multiples conservatives aux nœuds a été implémenté et validé, dans un contexte multidomaine. Le logiciel de simulation ainsi construit, a été validé sur des cas tests spécialement mis au point pour la fonderie, et en thermique multidomaine.This work deals with the numerical simulation of unsteady free surface flows of incompressible viscous fluids with finite element method. The industrial application consists of the filling stage of casting processes. It is based on the adaptation of an already existing software, REM3D®, which was initially dedicated to polymers injection moulding. Gravity and inertial effects have been introduced in the solver yielding a direct Navier Stokes method. Inertia description uses a piecewise linear interpolation of the velocity, and also the mean value of the velocity which is piecewise constant : the Galerkin discontinuous method is used to treat the advection terms.. This Navier Stokes equations resolution has been tested on several academic test cases: steady and non steady flow benchmarks have been chosen in order to validate only the mechanical solver, and afterwards, its coupling with the free surface solver. In order to simulate fluid metal flow, sliding boundary conditions have been introduced. An original algorithm of multiple consistent normal vectors has been implemented and validated. Finally, the filling stage of a specific casting benchmark has been studied, and mould filling have been carried out on industrial cases.PARIS-MINES ParisTech (751062310) / SudocSOPHIA ANTIPOLIS-INRIA I3S (061522305) / SudocSOPHIA ANTIPOLIS-Mines ParisTech (061522302) / SudocSudocFranceF