Evoked pleasure and approach-avoidance in response to pollution.

From year-to-year, environment is becoming one of the major concerns of human societies. Few studies have investigated the biological processes involved in environmental scene perception. Here, we initiate a line of research by beginning to study emotional processes involved in this perception. Our results demonstrate a clear distinction between "Clean" and "Polluted" environments according to the pleasure and approach desire ratings they induced. Moreover, women expressed higher pleasure in the "Clean" condition, as did older participants. Finally, rural scenes induced higher pleasure in participants than urban ones

Effet de l’incarnation sur les corrélats posturaux du traitement des stimuli aversifs

International audienceL’incarnation, habileté d’un individu à s’imaginer dans une situation, est sous-tendue par des processus cognitifs accrus par rapport à l’observation passive de la même scène. Pour étudier son potentiel effet modulateur sur les corrélats moteurs du traitement des stimuli aversifs, une étude de posturographie a été menée.Matériel et méthodesTrente stimuli émotionnels (base de données IAPS [1]) parmi lesquels on compte dix stimuli déplaisants sont présentés à 36 sujets (11 hommes/25 femmes, âgés de 36,3 ± 11,4 ans). Deux sessions expérimentales de post-urographie différant en termes de consignes sont organisées : une condition dite « passive » où une simple observation est demandée et une condition dite « active » où le participant doit s’imaginer dans la situation qui lui est présentée.RésultatsL’analyse de variance à mesures répétées effectuée sur divers paramètres (surface, position moyenne et écart-type de cette position) a permis de démontrer un effet consigne pour le paramètre de surface lors de la présentation de stimuli déplaisants. Les résultats montrent que la surface était plus importante en condition active (75,3 mm2 en actif pour 64,6 mm2 en passif).Discussion/ConclusionL’implication du participant lors de la présentation de stimuli aversifs induit un déplacement plus important du corps. Cette imagerie mentale (ou incarnation) de la situation observée induit une réponse motrice plus importante face à des stimuli déplaisants

Corrélats posturaux de la réaction instinctive à la présentation de stimuli visuels douloureux

International audienceL’impact de la présentation de stimuli émotionnels sur la sphère motrice a depuis longtemps été évoqué mais n’est étudié que depuis peu de temps. Une étude de Lelard et al. [1] a montré deux types de réponses instinctives vis-à-vis des stimuli déplaisants : la rigidification et l’évitement. Matériel et méthodes. Le protocole de présentation de Lelard et al. [1] a été repris en utilisant trente stimuli représentant des pieds et des mains dans des situations douloureuses (avec deux niveaux de douleur) ou non [2] chez 36 sujets (11 hommes/25 femmes, âgés de 36,3±11,4 ans). Deux sessions ont été organisées : une première en condition « passive » où une simple observation est demandée et une seconde en condition « active » où on demande au sujet de s’impliquer en s’imaginant dans la situation présentée. Résultats.Une tendance similaire aux travaux de l’équipe de Lelard et al. [1] a été obtenue pour les données recueillies en condition active. Une analyse temporelle des données montre un effet de la « douleur » et son intensité (p0,05), les valeurs sont respectivement −29,24 mm, −29,42 mm et −29,48 mm. Discussion/Conclusion. En condition active, l’évocation par l’image de la douleur induit ainsi une réponse posturale de recul proportionnelle à la douleur évoquée. Les réponses comportementales d’évitement observées agissent alors en tant que protecteur pour l’individu vis-à-vis de situations menaçantes, le préparant à l’agression avant toute autre action

Postural Correlates of Pollution Perception

In our contemporary societies, environmental issues are more and more important. An increasing number of studies explore the biological processes involved in environment perception and in particular try to highlight the mechanisms underlying the perception of environmental scenes by our brain. The main objective of the present study was to establish whether the visualization of clean and polluted environmental scenes would lead to differential postural reactions. Our hypothesis was based on a differential postural modulation that could be recorded when the subject is confronted with images representing a “polluted” environment, differential modulation which has been reported in previous studies in response to painful-scenes compared to non-painful scenes visualization.Thirty-one subjects participated in this study. Physiological measurements [heart rate variability (HRV) and electrodermal activity] and postural responses (Center Of Pression—COP—displacements) were recorded in response to perception of polluted or clean environmental scenes. We show, for the first time, that images representing polluted scenes evoke a weaker approach movement than images representing clean scenes. The displacement of the COP in the anteroposterior axis reflects an avoidance when subjects visualize “polluted” scenes. Our results demonstrate a clear distinction between “clean” and “polluted” environments according to the postural change they induce, correlated with the ratings of pleasure and approach evoked by images

Extra dissipation and flow uniformization due to elastic instabilities of shear-thinning polymer solutions in model porous media

International audienceWe study flows of hydrolized polyacrylamide solutions in two dimensional porous media made using microfluidics, for which elastic effects are dominant. We focus on semi-dilute solutions (0.1%–0.4%) which exhibit a strong shear thinning behavior. We systematically measure the pressure drop and find that the effective permeability is dramatically higher than predicted when the Weissenberg number is greater than about 10. Observations of the streamlines of the flow reveal that this effect coincides with the onset of elastic instabilities. Moreover, and importantly for applications, we show using local measurements that the mean flow is modified: it appears to be more uniform at high Weissenberg number than for Newtonian fluids. These observations are compared and discussed using pore network simulations, which account for the effect of disorder and shear thinning on the flow properties

Flow Enhancement due to Elastic Turbulence in Channel Flows of Shear Thinning Fluids

We explore the flow of highly shear thinning polymer solutions in straight geometry. The strong variations of the normal forces close to the wall give rise to an elastic instability. We evidence a periodic motion close the onset of the instability, which then evolves towards a turbulentlike flow at higher flow rates. Strikingly, we point out that this instability induces genuine drag reduction due to the homogenization of the viscosity profile by the turbulent flow. Viscoelastic polymer solutions are characterized by a relaxation time λ required by the polymer molecules to adjust to changes in the flow conditions. This time is at the origin of purely elastic instabilities observed at very low Reynolds numbers with no counterpart in pure Newtonian fluids. In shear flows, purely elastic instabilities arise due to stress tensor anisotropy inducing a destabilizing net force perpendicularly to curved streamlines [1–3]. These instabilities can lead to purely elastic turbulence [4–6]. In straight channels, theoretical studies demonstrate that the viscosimetric properties of the fluid play a major role in the stability of the flow. Plane Couette flows [7] and Poiseuille flows [8] of Oldroyd-B fluids exhibit a nonlinear subcritical elastic instability although the base flow is linearly stable [9]. Recent experiments [10,11] have shown that finite amplitude perturbation creates curved stream-lines that drive the instability. In contrast, channel flows of highly shear thinning fluids [12–14] are theoretically linearly unstable. The instability is driven in this case by the strong variations of both normal stress and viscous dissipation in the shear direction. An extreme situation is obtained with shear banding fluids, where the interface bears an unbalanced normal stress [14]. This leads to an interfacial instability which has been observed experimen-tally [15]. A similar mechanism is theoretically expected without shear banding but requires a strong gradient of shear rate [13]. At this stage, channel flow stability of such liquids has not been studied experimentally, although shear thinning is a very common feature of elastic fluids. In this Letter, we focus on highly shear thinning elastic polymer solutions with no shear banding flowing in straight channels. At low flow rates, no velocity fluctuations are observed. At higher flow rates, the power spectrum density of the velocity fluctuations displays a distinct peak indicat-ing the onset of instability. The position of the peak is in agreement with theoretical predictions for highly shear thinning fluids [13]. At even higher flow rates, the fluctuations occur at all scales and the spectrum becomes broadband with a power law decay. This instability induces genuine drag reduction: viscous losses are smaller than expected from the fluid rheology. This is a remarkable result since one expects additional energy losses due to the enhancement of velocity fluctuations. We study the flow of high molecular weight polymer solutions (18 × 10 6 g=mol partially hydrolyzed polyacry-lamide) in water at different concentrations in the semi-dilute regime. The global flow curves of these solutions are determined using the shear-rate-imposed mode of a rheometer (TA Instruments ARG2) in a sanded cone-and-plate geometry of angle θ ¼ 2°. Figure 1 reports both the shear stress σ and the Weissenberg number Wi ¼ N 1 =2σ a

ARF promotes the degradation of the Epidermal Growth Factor Receptor by the lysosome

International audienceEpidermal Growth Factor Receptor (EGFR) signaling regulates multiple cellular processes including proliferation , survival and apoptosis, and is attenuated by lysosomal receptor degradation. EGFR is a potent oncogene and activating mutations of EGFR are critical determinants of oncogenic transformation as well as therapeutic targets in non-small cell lung cancer. We previously demonstrated that wild type and mutant EGFRs repress the expression of the ARF tumor suppressor to promote the survival of lung tumor cells. In this study, using transient transfection systems in CHO EGFR-null cells as well as in various lung tumor cell lines carrying wild type or activated mutant EGFR, we show that ARF downregulates the expression of EGFR protein by reducing its half life. In wild type EGFR cells, ARF promotes canonical lysosomal degradation of the receptor through enhanced phosphorylation of EGFR-Y1045 and Cbl-Y731. In contrast, in mutant EGFR cells, ARF induces EGFR degradation by activating a non-canonical AKT-dependent lysosomal pathway. Taken together, these results uncover a feedback loop by which ARF may control EGFR turnover to restrain oncogenic signaling. They also highlight distinct degradation promoting pathways between wild type and mutant EGFRs in response to ARF

Assessment of Left Ventricular Ejection Fraction Calculation on Long-axis Views From Cardiac Magnetic Resonance Imaging in Patients With Acute Myocardial Infarction

International audienceTo assess left ventricular ejection fraction (LVEF) accurately, cardiac magnetic resonance (CMR) can be indicated and lays on the evaluation of multiple slices of the left ventricle in short axis (CMRSAX). The objective of this study was to assess another method consisting of the evaluation of 2 long-axis slices (CMRLAX) for LVEF determination in acute myocardial infarction.One hundred patients underwent CMR 2 to 4 days after acute myocardial infarction. LVEF was computed by the area-length method on horizontal and vertical CMRLAX images. Those results were compared to reference values obtained on contiguous CMRSAX images in one hand, and to values obtained from transthoracic echocardiography (TTE) in the other hand. For CMRSAX and TTE, LVEF was computed with Simpson method. Reproducibility of LVEF measurements was additionally determined. The accuracy of volume measurements was assessed against reference aortic stroke volumes obtained by phase-contrast MR imaging.LVEF from CMRLAX had a mean value of 47 ± 8% and were on average 5% higher than reference LVEF from CMRSAX (42 ± 8%), closer to routine values from TTELAX (49 ± 8%), much better correlated with the reference LVEF from CMRSAX (R = 0.88) than that from TTE (R = 0.58), obtained with a higher reproducibility than with the 2 other techniques (% of interobserver variability: CMRLAX 5%, CMRSAX 11%, and TTE 13%), and obtained with 4-fold lower recording and calculation times than for CMRSAX. Apart from this, CMRLAX stroke volume was well correlated with phase-contrast values (R = 0.81).In patients with predominantly regional contractility abnormalities, the determination of LVEF by CMRLAX is twice more reproducible than the reference CMRSAX method, even though the LVEF is consistently overestimated compared with CMRSAX. However, the CMRLAX LVEF determination provides values closer to TTE measurements, the most available and commonly used method in clinical practice, clinical trials, and guidelines in ischemic cardiomyopathy. Moreover, LVEF determination by CMRLAX allows a 63% gain of acquisition/reading time compared with CMRSAX. Thus, despite the fact that LVEF obtained from CMRSAX remains the gold standard, CMRLAX should be considered to shorten the overall imaging acquisition and reading time as a putative replacement

Chiismes politiques

De l’islam politique chiite, l’on ne connaît souvent que deux de ses incarnations les plus visibles internationalement : la République islamique d’Iran et le Hezbollah libanais. Tout au long de leur construction au XXe siècle, cependant, les usages politiques de la référence religieuse chiite ont donné lieu à des expressions différenciées, dans les représentations comme dans les pratiques, bien loin d’une reproduction de l’idéologie khomeynienne de la wilāyat al-faqīh. La chute de Saddam Hussein et l’avènement d’une nouvelle ère politique en Irak à partir de 2003, puis l’internationalisation du conflit qui a ravagé la Syrie ces dernières années, ont contribué à mettre en évidence cette variété des façons dont se trouve mobilisé un univers symbolique chiite partagé. Ce dossier thématique se propose d’observer quelques expressions actuelles de ces chiismes politiques, dans différents contextes nationaux : de la Turquie où l’islam chiite est minoritaire à l’Iran où il fut édifié religion d’État, en passant par le Liban, l’Irak, la Palestine, le Yémen et jusqu’à la France d’où il se trouve pourtant quasiment absent, la référence politique à l’islam chiite se trouve incarnée dans des configurations de pouvoir, des imaginaires sociaux, des formes d’engagement politique, des identités personnelles et partisanes extrêmement diverses. C’est de cette diversité que ces contributions voudraient rendre compte, en s’intéressant à des organisations partisanes autant qu’à des acteurs politiques ordinaires, et en privilégiant l’étude de cas peu connus de la recherche francophone, par des sociologues, anthropologues et politistes qui nous livrent ici le produit d’enquêtes de terrain au plus près de leur objet