Permafrost model sensitivity to seasonal climatic changes and extreme events in mountainous regions

Climate models project considerable ranges and uncertainties in future climatic changes. To assess the potential impacts of climatic changes on mountain permafrost within these ranges of uncertainty, this study presents a sensitivity analysis using a permafrost process model combined with climate input based on delta-change approaches. Delta values comprise a multitude of coupled air temperature and precipitation changes to analyse long-term, seasonal and seasonal extreme changes on a typical low-ice content mountain permafrost location in the Swiss Alps. The results show that seasonal changes in autumn (SON) have the largest impact on the near-surface permafrost thermal regime in the model, and lowest impacts in winter (DJF). For most of the variability, snow cover duration and timing are the most important factors, whereas maximum snow height only plays a secondary role unless maximum snow heights are very small. At least for the low-ice content site of this study, extreme events have only short-term effects and have less impact on permafrost than long-term air temperature trends

Denoising 3D microscopy images of cell nuclei using shape priors on an anisotropic grid

This paper presents a new multiscale method to denoise three-dimensional images of cell nuclei. The speci- ficity of this method is its awareness of the noise distribution and object shapes. It combines a multiscale representation called Isotropic Undecimated Wavelet Transform (IUWT) with a nonlinear transform, a statistical test and a variational method, to retrieve spherical shapes in the image. Beyond extending an existing 2D approach to a 3D problem, our algorithm takes the sampling grid dimensions into account. We compare our method to the two algorithms from which it is derived on a representative image analysis task, and show that it is superior to both of them. It brings a slight improvement in the signal-to-noise ratio and a significant improvement in cell detection

Co-design of the Medical Assistive and Transactional Technologies system

National audienceThis paper could argue that the co-design method is strongly needed to design acceptable and usable assistive technologies. It describes the co-design of the Medical Assistive and Transactional Technologies (MATT) system. This method was implemented for Matthieu a quadriplegic and a non verbal person. The paper reports how the collaborative design was running between Matthieu, his occupational therapists, his family and the designer team

Entre banalité et exotisme, le panel individuel des destinations touristiques

International audienceThe globalization of the tourism expresses at the same time by the emergence of new markets and the dilation of the tourist space. Numerous questioning remain on the way this second process is embodied in the individual practices. How are articulated close and distant movements? What are the relations between spatial pattern of the tourist mobilities and profile of the mobile persons? The analysis proposed aims at lighting these questions by exploiting the data of a survey from ANR-Merev on the temporary mobilities realized in 2008-2009, with more than 1800 persons living in Berlin, Brussels, London or Paris. In this way, it confronts two contrasted visions of the spatial pattern of tourist practices, the one advancing the segmentation of the practices of mobility according to the personalities, the other one suggesting a generalized hybridization of these practices. The obtained results show that within mobile populations, the spatial pattern of the destinations remains very segmented, according to the socioeconomic characteristics of the individuals.La mondialisation du tourisme s'exprime à la fois par l'émergence de nouveaux foyers émetteurs et la dilatation de l'oekoumène touristique. De nombreuses interrogations subsistent sur la manière dont ce second processus s'incarne dans les pratiques individuelles. Comment s'articulent déplacements proches et lointains ? Quelles sont les relations entre canevas spatiaux des mobilités touristiques et profil des personnes mobiles ? L'analyse proposée vise à éclairer ces questions en exploitant les données d'une enquête de l'ANR-Merev sur les mobilités temporaires, réalisée en 2008-2009 auprès de plus de 1800 personnes résidant à Berlin, Bruxelles, Londres ou Paris. Dans cette optique, elle confronte deux visions contrastées du rapport à l'altérité, l'une mettant en avant la segmentation des pratiques de mobilité selon les personnalités, l'autre suggérant une hybridation généralisée de ces pratiques. Les résultats obtenus montrent qu'au sein même de populations mobiles, le canevas spatial des destinations reste très segmenté, selon les caractéristiques socio-économiques et socio-professionnelles des individus

Human FDC express PrPc in vivo and in vitro

Prion diseases are fatal neurodegenerative disorders caused by accumulation of abnormal prion protein (protease-resistant prion, PrPres). PrPres accumulation is also detected in lymphoid organs after peripheral infection. Several studies suggest that follicular dendritic cells (FDC) could be the site of PrPres retention and amplification

Do Bovine Lymphocytes Express a Peculiar Prion Protein?

The cellular prion protein (PrPc) is a glycolipid-anchored cell surface protein that usually exhibits three glycosylation states. Its post-translationally modified isoform, PrPsc, is involved in the pathogenesis of various transmissible spongiform encephalopathies (TSEs). In bovine species, BSE infectivity appears to be restricted to the central nervous system; few or no detectable infectivity is found in lymphoid tissues in contrast to scrapie or variant CJD. Since expression of PrPc is a prerequisite for prion replication, we have investigated PrPc expression by bovine immune cells. Lymphocytes from blood and five different lymph organs were isolated from the same animal to assess intra- and interindividual variability of PrPc expression, considering six individuals. As shown by flow cytometry, this expression is absent or weak on granulocytes but is measurable on monocytes, B and T cells from blood and lymph organs. The activation of the bovine cells produces an upregulation of PrPc. The results of our in vitro study of PrPc biosynthesis are consistent with previous studies in other species. Interestingly, western blotting experiments showed only one form of the protein, the diglycosylated band. We propose that the glycosylation state could explain the lack of infectivity of the bovine immune cells

Mouse vaccination with dendritic cells loaded with prion protein peptides overcomes tolerance and delays scrapie.

Prion diseases are presumed to be caused by the accumulation in the brain of a pathological protein called prion protein (PrP) scrapie which results from the transconformation of cellular PrP, a ubiquitous glycoprotein expressed in all mammals. Since all isoforms of PrP are perceived as self by the host immune system, a major problem in designing efficient immunoprophylaxis or immunotherapy is to overcome tolerance. The present study was aimed at investigating whether bone-marrow-derived dendritic cells (DCs) loaded with peptides previously shown to be immunogenic in PrP-deficient mice, can overcome tolerance in PrP-proficient wild-type mice and protect them against scrapie. Results show that, in such mice, peptide-loaded DCs elicit both lymphokine release by T cells and antibody secretion against native cellular PrP. Repeated recalls with peptide-loaded DCs reduces the attack rate of 139A scrapie inoculated intraperitoneally and retards disease duration by 40 days. Most interestingly, survival time in individual mice appears to be correlated with the level of circulating antibody against native cellular PrP

Environmental Impacts of Large-Scale Grid-Connected Ground-Mounted PV Installations

Available on: http://www.ep.liu.se/ecp/057/vol11/007/ecp57vol11_007.pdfInternational audienceThis study characterizes the environmental performances of large-scale ground-mounted PV installations by considering a life-cycle approach. The methodology is based on the application of the existing international standards of Life Cycle Assessment (LCA). Four scenarios are compared, considering fixedmounting structures with (1) primary aluminum supports or (2) wood supports, and mobile structures with (3) single-axis trackers or (4) dual-axis trackers. Life cycle inventories are based on manufacturers' data combined with additional calculations and assumptions. Fixed-mounting installations with primary aluminum supports show the largest environmental impact potential with respect to human health, climate change and energy consumption. The climate change impact potential ranges between 37.5 and 53.5 gCO2eq/kWh depending on the scenario, assuming 1700 kWh/m².yr of irradiation on an inclined plane (30°), and multi-crystalline silicon modules with 14% of energy production performance. Mobile PV installations with dual-axis trackers show the largest impact potential on ecosystem quality, with more than a factor 2 of difference with other considered installations. Supports mass and composition, power density (in MWp/acre of land) and energy production performances appear as key design parameters with respect to large-scale ground mounted PV installations environmental performances, in addition to modules manufacturing process energy inputs