On the Efficiency of Backtracking Algorithms for Binary Constraint Satisfaction Problems

International audienceThe question of tractable classes of constraint satisfaction problems (CSPs) has been studied for a long time, and is now a very active research domain. However, studies of tractable classes are typically very theoretical. They usually introduce classes of instances together with polynomial time algorithms for recognizing and solving them, and the algorithms can be used only for the new class. In this paper, we address the issue of tractable classes of CSPs from a different perspective. We investigate the complexity of classical, generic algorithms for solving CSPs (such as Forward Checking). We introduce a new parameter for measuring their complexity and derive new complexity bounds. By relating the complexity of CSP algorithms to graph-theoretic parameters, our analysis allows us to point at new tractable classes, which can be solved directly by the usual CSP algorithms in polynomial time, and without the need to recognize the classes in advance

Genetic deficiency of indoleamine 2,3-dioxygenase promotes gut microbiota-mediated metabolic health.

The association between altered gut microbiota, intestinal permeability, inflammation and cardiometabolic diseases is becoming increasingly clear but remains poorly understood1,2. Indoleamine 2,3-dioxygenase is an enzyme induced in many types of immune cells, including macrophages in response to inflammatory stimuli, and catalyzes the degradation of tryptophan along the kynurenine pathway. Indoleamine 2,3-dioxygenase activity is better known for its suppression of effector T cell immunity and its activation of regulatory T cells3,4. However, high indoleamine 2,3-dioxygenase activity predicts worse cardiovascular outcome5-9 and may promote atherosclerosis and vascular inflammation6, suggesting a more complex role in chronic inflammatory settings. Indoleamine 2,3-dioxygenase activity is also increased in obesity10-13, yet its role in metabolic disease is still unexplored. Here, we show that obesity is associated with an increase of intestinal indoleamine 2,3-dioxygenase activity, which shifts tryptophan metabolism from indole derivative and interleukin-22 production toward kynurenine production. Indoleamine 2,3-dioxygenase deletion or inhibition improves insulin sensitivity, preserves the gut mucosal barrier, decreases endotoxemia and chronic inflammation, and regulates lipid metabolism in liver and adipose tissues. These beneficial effects are due to rewiring of tryptophan metabolism toward a microbiota-dependent production of interleukin-22 and are abrogated after treatment with a neutralizing anti-interleukin-22 antibody. In summary, we identify an unexpected function of indoleamine 2,3-dioxygenase in the fine tuning of intestinal tryptophan metabolism with major consequences on microbiota-dependent control of metabolic disease, which suggests indoleamine 2,3-dioxygenase as a potential therapeutic target

Obesity Paradox in the Clinical Significance of Effective Prosthetic Orifice Area after Aortic Valve Replacement.

peer reviewe

4. La dynamique séculaire d’industrialisation dans les vallées des Morin et de la Marne

Les vallées du Grand Morin, du Petit Morin et de la Marne entre La Ferté-sous-Jouarre et Esbly, entaillent le plateau agricole de la Brie. Ces vallées ont connu des processus d’industrialisation précoces, liés à l’exploitation de la force motrice actionnée par des moulins. Les industries ainsi créées étaient très diverses. Logiquement, les industries agro-alimentaires (fromagerie, sucrerie, conserverie et vermicellerie) constituent une part importante de l’activité industrielle des vallées, ..

Data transfer, collection and organisation for multi-centric clinical studies

International audienc

Data transfer, collection and organisation for multi-centric clinical studies

International audienc

Transfer, Collection and Organisation of Electrophysiological and Imaging Data for Multicentre Studies

International audienceMulticentre studies are of utmost importance to conrm hypotheses. The lack of established standards and the ensuing complexity of their datamanagement often hamper their implementation. The Brain Imaging Data Structure (BIDS) is an initiative for organizing and describing neuroimagingand electrophysiological data. Building on BIDS, we have developed two software programs: BIDS Manager and BIDS Uploader. The former has beendesigned to collect, organise and manage the data and the latter has been conceived to handle their transfer and anonymisation from the partner centres. These two programs aim at facilitating the implementation of multicentre study by providing a standardised framework

Effects of acid-treated silicon nanowires on hybrid solar cells performance

International audienceWe demonstrate the efficiency improvement of hybrid solar cells based on silicon nanowires (SiNWs) and organic materials. This progress is readily achieved by acid treatments of SiNWs. Tin (Sn) catalyzed SiNWs contain residual Sn and Sn oxide drops on their top which are deleterious for a solar cell performance. Removal of this Sn and Sn oxide contamination is performed with hydrochloric acid. X-ray photoelectron spectroscopy measurement verified that the amount of Sn and Sn oxide on SiNWs array is decreased according to the immersing time. This brings open-circuit voltage and shunt resistance increase thus the hybrid solar cell performance is improved. Light intensity dependent open-circuit voltage clearly reveals that this efficiency improvement results from a reduced trap-assisted recombination through Sn and Sn oxide. In addition to the residual catalysts removal, native oxide removal by hydrofluoric acid also considerably contributes to further improvement in terms of short-circuit current and fill factor. Clearly, the improvement of SiNWs quality is essential for an optimization of hybrid solar cell performance

Raman and PAS Characterization of Electron Irradiated UO2 to Determine U Displacement Threshold

International audienc

Raman and PAS Characterization of Electron Irradiated UO2 to Determine U Displacement Threshold

International audienc