Influence of response prepotency strength, general working memory resources, and specific working memory load on the ability to inhibit predominant responses: A comparison of young and elderly participants

One conception of inhibitory functioning suggests that the ability to successfully inhibit a predominant response depends mainly on the strength of that response, the general functioning of working memory processes, and the working memory demand of the task (Roberts, Hager, and Heron, 1994). The proposal that inhibition and functional working memory capacity interact was assessed in the present study using two motor inhibition tasks (Go/No-Go and response incompatibility) in young and older participants. The strength of prepotency was assessed with a short or long training phase for the response to be inhibited. The influence of working memory resources was evaluated by administering the tasks in full versus divided attention conditions. The effect of working memory load was manipulated by increasing the number of target and distracter items in each task. Results showed no effect of prepotency strength, whereas dividing attentional resources and increasing working memory load were associated with greater inhibitory effects in both groups and for both tasks. This deleterious effect was higher for older participants, except in the working memory load condition of the Go/No-Go task. These results suggest an interactive link between working memory and response inhibition by showing that taxing working memory resources increases the difficulty of inhibiting prepotent responses in younger and older subjects. The additional detrimental effect of these factors on healthy elderly subjects was related to their decreased cognitive resources and to their shorter span size

Quasi-Newton inversion of seismic first arrivals using source finite bandwidth assumption: Application to subsurface characterization of landslides

International audienceCharacterizing the internal structure of landslides is of first importance to assess the hazard. Many geophysical techniques have been used in the recent years to image these structures, and among them is seismic tomography. The objective of this work is to present a high resolution seismic inversion algorithm of first arrival times that minimizes the use of subjective regularization operators. A Quasi-Newton P-wave tomography inversion algorithm has been developed. It is based on a finite frequency assumption for highly heterogeneous media which considers an objective inversion regularization (based on the wave propagation principle) and uses the entire source frequency spectrum to improve the tomography resolution. The Fresnel wavepaths calculated for different source frequencies are used to retropropagate the traveltime residuals, assuming that in highly heterogeneous media, the first arrivals are only affected by velocity anomalies present in the first Fresnel zone. The performance of the algorithm is first evaluated on a synthetic dataset, and further applied on a real dataset acquired at the Super-Sauze landslide which is characterized by a complex bedrock geometry, a layering of different materials and important changes in soil porosity (e.g. surface fissures). The seismic P-wave velocity and the wave attenuation are calculated, and the two tomographies are compared to previous studies on the site

Quasi-Newton algorithm using Fresnel wavepaths and frequency increase for P-wave tomography inversion: application to a landslide in the South French Alps

EGU2012-4323During last decases, geophysical methods have become of a great interest in geomorphological studies. Because they are well adapted to retrieve geological structures as variations in the spatial and temporal dimensions of rocks properties, they were widely developed for improving landslides understanding. Landslide studies generally involve the use of several geophysical methods, but among them, seismic surveys are well adapted to identify the slope's main structures. The wave propagation being mainly controlled by elastic properties of the medium, this method makes the interpretation easier since results are often well correlated with geotechnical observations. More generally, it provides information on the mechanical state of the soils with an acceptable spatial resolution. This structure is of first importance when studying clayey landslides as the Super-Sauze one. It occurred in the 1960s with the falls of large blocks and has developed continually covering an intact paleotopography. This succession of crests and gullies has been studied by geotechnical measurement and geophysics. It plays a large role in the behavior of the flow by delimiting preferential water and material pathways and compartments with different kinematics, mechanical and hydro dynamical characteristics. For the first time, a 3D geological model has been created from the fusion of multi-source data by Travelletti and Malet (2011), but it appears that geophysical methods can't capture the sharp geometry of the paleotopography. To improve such models and the numerical modeling resulting we propose a Quasi-Newton algorithm based on the Fresnel-wavepath and the frequency increase to the invert P-wave velocity fiel

Influence des défauts de forme sur les performances d'assemblages (application aux prothèses totales de hanche)

La performance des mécanismes est intimement liée à la précision des surfaces qui composent les liaisons. La démarche habituelle de l analyse de ces surfaces est basée sur des hypothèses fortes concernant leurs comportements. Ainsi, les défauts de forme et de rugosité sont négligés et les surfaces sont supposées infiniment rigides. L objectif principal de ces travaux est de développer une méthode permettant d étudier l influence des défauts de forme sur les performances des assemblages. Elle repose sur une méthodologie et des outils pour l identification des défauts qui vont optimiser ou pénaliser les exigences fonctionnelles de l assemblage. Dans ce manuscrit, deux cas d étude sont proposés.Dans un premier temps, un montage de type bride (centrage court, appui plan) est étudié afin de valider l ensemble de la démarche développée. Les outils utilisés reposent essentiellement sur la décomposition et composition modale des défauts, le concept de surface écarts, la recherche de zone d appui stable ainsi que la quantification des déformations de surfaces de contact basées sur des modèles analytiques ou numériques. L influence des défauts de forme sur la précision de mise en position est quantifiée par un domaine écart de liaison. Une confrontation entre la démarche théorique et un dispositif expérimental permet de valider l approche. Par la suite, une liaison sphérique est considérée constituant une prothèse totale de hanche en matériau céramique. Pour ce cas d étude, l objectif est d identifier, au regard des typologies de défauts, leurs conséquences sur l apparition d un phénomène sonore assimilable à du grincement appelé le squeaking. La démarche reprend les mêmes étapes que celles utilisées avec l étude de la bride. Différents dispositifs expérimentaux sont mis en place confirmant la pertinence de cette approche. Des mesures spécifiques apportent des éléments d analyse et de compréhension sur le comportement dégradé de la liaison. Ce travail de thèse s inscrit dans une collaboration entre 3 laboratoires : SYMME d Annecy, I2M-IMC de Bordeaux-Talence, et la société Tural localisée à Marignier (74), laboratoire de recherche industrielle qui travaille sur des implants médicaux.The performance of a mechanism is closely correlated with the accuracy of the surfaces that make up the mechanical joint. The most common approach used to study these surfaces is based on strong assumptions about their behavior. Form errors and roughness are neglected and the surfaces are assumed infinitely rigid. The main objective of this work is to develop an original approach to study the impact of form errors on the assemblies. It is mainly based on a methodology and associated tools to predict which defects will optimize or penalize the functional requirements of the assembly. In this manuscript, two case studies are proposed. In a first step, a plate flange (ball and cylinder joints added to a planar joint) is designed to validate the overall approach. Modal decomposition of defects, sum-surface concept, the determination of a stable contact area and quantification of contact deformation of surfaces correspond to the main theoretical tools used in this framework. The influence of form errors on the positioning accuracy is quantified by a clearance domain. Comparisons between theoretical approach and experimental setup are used to validate the models. Subsequently, a spherical joint is considered corresponding to a total hip implant with ceramic material. The objective of this study is to identify which type of form errors can impact the appearance of the squeaking phenomena. The same procedure is followed as for the first example. In parallel, several experimental devices are designed to validate the relevance of this approach. Specific measurements provide some key elements to understand the behavior of the implant subject to squeaking. This work is part of a collaboration between three laboratories : SYMME Annecy, I2M-IMC Bordeaux, and Tural company located in Marignier (74), an industrial research laboratory working on medical implants.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Acute Coronary Artery Air-Embolism after Percutaneous Lung Biopsy

peer reviewe

Influence des défauts de forme dans les assemblages de surfaces planes

Ce papier propose de se focaliser sur les déformations locales des liaisons particulière de type appui plan centrage court couramment utilisée pour la jonction entre deux carters (corps de pompe, turbomoteur ). L'approche proposée permet de mettre en évidence sur un cas simple l'importance de la prise en compte des défauts de forme dans le comportement des liaisons et d'étudier l'influence des déformations locales sur la performance finale d'un mécanisme. Le niveau de performance sera exprimé en fonction du taux de non conformité d'une spécification fonctionnelle de l'assemblage

The first record of translocated white-clawed crayfish from the Austropotamobius pallipes complex in Sardinia (Italy)

<p>The white-clawed crayfish <em>Austropotamobius pallipes </em>complex is native to Europe, being present in 18 European countries, Italy included. However, the number and abundance of its populations are today restricted and it has been recently classified as “endangered” by IUCN (International Union for Conservation of Nature). Here, we report the first record of this freshwater crayfish in Sardinia Island (Italy). Using a fragment of the mitochondrial DNA 16S rRNA gene, we identified three haplotypes that correspond to the <em>A. italicus meridionalis </em>subclade. We provide information about the sampling area, population density and finally discuss hypotheses about the occurrence of this population in Sardinia, comparing it with other Mediterranean populations. Our results improve the existing knowledge about the phylogeography of the taxon across Italy, confirming its complex pattern of distribution. In addition to the non-native status of the Sardinian <em>A. i. meridionalis</em> crayfish, we showed that the most proximal Mediterranean population of white-clawed crayfish existing in Corsica belongs to <em>A. pallipes</em> from Southern France.</p

A multidisciplinary approach to landslide structure characterization: integration of seismic tomography survey and high resolution LiDar data with the Sloping Local Base Level method.

International audienceA challenge to progress in the understanding of landslides is to precisely define their 3D geometry and structure as an input for volume estimation and further hydro-mechanical modelling. The objective of this work is to present a multidisciplinary approach to the geometrical modelling of the La Valette landslide by integrating seismic tomography survey (P and S wave) and high resolution LiDar data with the Sloping Local Base Level (SLBL) method. The La Valette landslide, triggered in March 1982, is one of the most important slope instability in the South French Alps. Its dimensions are 1380 m length and 290 m width, and the total volume is estimated at 3.5 106 m3. Since 2002, an important activity of the upper part of the landslide is observed, and consisted mainly in the retrogression of the crown through the opening of an important fracture over several meters and rotational slumps. The failed mass is currently loading the upper part of the mudslide and is a potential threat for the 170 residential communities

Social context and drug cues modulate inhibitory control in cocaine addiction:involvement of the STN evidenced through functional MRI

Addictions often develop in a social context, although the influence of social factors did not receive much attention in the neuroscience of addiction. Recent animal studies suggest that peer presence can reduce cocaine intake, an influence potentially mediated, among others, by the subthalamic nucleus (STN). However, there is to date no neurobiological study investigating this mediation in humans. This study investigated the impact of social context and drug cues on brain correlates of inhibitory control in individuals with and without cocaine use disorder (CUD) using functional Magnetic Resonance Imaging (fMRI). Seventeen CUD participants and 17 healthy controls (HC) performed a novel fMRI “Social” Stop-Signal Task (SSST) in the presence or absence of an observer while being exposed to cocaine-related (vs. neutral) cues eliciting craving in drug users. The results showed that CUD participants, while slower at stopping with neutral cues, recovered control level stopping abilities with cocaine cues, while HC did not show any difference. During inhibition (Stop Correct vs Stop Incorrect), activity in the right STN, right inferior frontal gyrus (IFG), and bilateral orbitofrontal cortex (OFC) varied according to the type of cue. Notably, the presence of an observer reversed this effect in most areas for CUD participants. These findings highlight the impact of social context and drug cues on inhibitory control in CUD and the mediation of these effects by the right STN and bilateral OFC, emphasizing the importance of considering the social context in addiction research. They also comfort the STN as a potential addiction treatment target

Lattice matched GaN/InAlN waveguides at λ = 1.55 μm grown by metalorganic vapor phase epitaxy

We report on the demonstration of low-loss, single-mode GaN-InAlN ridge waveguides (WGs) at fiber-optics telecommunication wavelengths. The structure grown by metal-organic vapor phase epitaxy contains AlInN cladding layers lattice-matched to GaN. For slab-like WGs propagation losses are below 3 dB/mm and independent of light polarization. For 2.6-μm-wide WGs the propagation losses in the 1.5- to 1.58-μm spectral region are as low as 1.8 and 4.9 dB/mm for transverse-electric- and transverse-magnetic-polarization, respectively. The losses are attributed to the sidewall roughness and can be further reduced by the optimization of the etching process