Cartesian product of hypergraphs: properties and algorithms

Cartesian products of graphs have been studied extensively since the 1960s. They make it possible to decrease the algorithmic complexity of problems by using the factorization of the product. Hypergraphs were introduced as a generalization of graphs and the definition of Cartesian products extends naturally to them. In this paper, we give new properties and algorithms concerning coloring aspects of Cartesian products of hypergraphs. We also extend a classical prime factorization algorithm initially designed for graphs to connected conformal hypergraphs using 2-sections of hypergraphs

Factorization of products of hypergraphs: Structure and algorithms

International audienceOn the one hand Cartesian products of graphs have been extensively studied since the 1960s. On the other hand hypergraphs are a well-known and useful generalization of graphs. In this article, we present an algorithm able to factorize into its prime factors any bounded-rank and bounded-degree hypergraph in O(nm), where n is the number of vertices and m is the number of hyperedges of the hypergraph. First the algorithm applies a graph factorization algorithm to the 2-section of the hypergraph. Then the 2-section factorization is used to build the factorization of the hypergraph via the factorization of its L2-section. The L2-section is a recently introduced way to interpret a hypergraph as a labeled-graph. The graph factorization algorithm used in this article is due to Imrich and Peterin and is linear in time and space. Nevertheless any other such algorithm could be extended to a hypergraph factorization algorithm similar to the one presented here

Traitement d'images scanographiques appliqué à l'étude tridimensionnelle de l'évolution de la forme du crâne humain

Extended proceedings of the workshop organized in May 1999.National audienceWe present an automatic method that allows one to visualize and analyze, in three dimensions, the evolution of the shape of the human skull from CT-Scan images. A first algorithm automatically extracts the crest lines from CT-Scan images of the skull of a modern Man and of a cast of a skull of a prehistoric Man. Those lines correspond to the salient lines of the skull surface. They will be used as landmarks to automatically find the homology points between the two skulls. Based on these couples of matched points, we compute a volumetric transformation that superposes the two skulls. This transformation can be interpolated to obtain intermediary transformations. We extract then a surface model of the skull of the modern Man and we apply successively the intermediary transformations to visualize the evolution of the sull between the prehistoric and the modern Man. We have applied this method to the skull of the Man of Tautavel, dated of about 450 000 years, and we present future applications in facial reconstruction and tridimensional morphometry.Nous présentons une méthode automatique qui permet de visualiser et d'analyser, en trois dimensions , l'évolution de la forme du crâne humain à partir d'images scanographiques. Un premier algorithme extrait automatiquement des lignes de crête à partir des scanographies d'un crâne d'un Homme moderne et du moulage du crâne d'un Homme préhistorique. Ces lignes correspondent aux lignes saillantes de la surface crânienne. Elles servent de repères à un algorithme de mise en correspondance pour trouver automatiquement les points homologues entre les deux crânes. A partir de ces points appariés, on calcule une transformation de l'espace qui superpose les deux crânes. Cette transformation peut ensuite être interpolée pour créer des transformations intermé-diaires. A partir de l'image scanographique, on extrait alors un modèle surfacique du crâne de l'Homme moderne auquel sont successivement appliquées les transformations intermédiaires pour visualiser l'évolution du crâne entre l'Homme préhistorique et moderne. Nous appliquons cette méthode au crâne de l'Homme de Tautavel, daté d'environ 450 000 ans, et nous présentons des applications futures en reconstruction faciale et en analyse morphométrique tridimensionnelle

The anti-caspase inhibitor Q-VD-OPH prevents AIDS disease progression in SIV-infected rhesus macaques

Apoptosis has been proposed as a key mechanism responsible for CD4+ T cell depletion and immune dysfunction during HIV infection. We demonstrated that Q-VD-OPH, a caspase inhibitor, inhibits spontaneous and activation-induced death of T cells from SIV-infected rhesus macaques (RMs). When administered during the acute phase of infection, Q-VD-OPH was associated with (a) reduced levels of T cell death, (b) preservation of CD4+/CD8+ T cell ratio in lymphoid organs and in the gut, (c) maintenance of memory CD4+ T cells, and (d) increased specific CD4+ T cell response associated with the expression of cytotoxic molecules. Although therapy was limited to the acute phase of infection, Q-VD-OPH-treated RMs showed lower levels of both viral load and cell-associated SIV DNA as compared with control SIV-infected RMs throughout the chronic phase of infection, and prevented the development of AIDS. Overall, our data demonstrate that Q-VD-OPH injection in SIV-infected RMs may represent an adjunctive therapeutic agent to control HIV infection and delaying disease progression to AIDS.This article is dedicated to the memory of Bruno Hurtrel. We also thank Jean-Claude Ameisen for his initial support. We acknowledge Celine Gommet (Institut Pasteur) for her expertise in the follow-up of our primate cohort. We also acknowledge Francois Villinger, who performed TRIM5a polymorphism. ML and JG were supported by fellowships from ANRS. RS thanks Fundacao para a Ciencia e a Tecnologia (FCT) for Investigator FCT Grant IF/00021/2014. This study was supported by research funding from ANRS and CIHR (MOP-133476) to JE. VR is supported by a fellowship from FCT (code SFRH/BD/64064/2009). JE thanks the Canada Research Chair program for financial assistance

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

B lymphocytes trigger monocyte mobilization and impair heart function after acute myocardial infarction.

Acute myocardial infarction is a severe ischemic disease responsible for heart failure and sudden death. Here, we show that after acute myocardial infarction in mice, mature B lymphocytes selectively produce Ccl7 and induce Ly6C(hi) monocyte mobilization and recruitment to the heart, leading to enhanced tissue injury and deterioration of myocardial function. Genetic (Baff receptor deficiency) or antibody-mediated (CD20- or Baff-specific antibody) depletion of mature B lymphocytes impeded Ccl7 production and monocyte mobilization, limited myocardial injury and improved heart function. These effects were recapitulated in mice with B cell-selective Ccl7 deficiency. We also show that high circulating concentrations of CCL7 and BAFF in patients with acute myocardial infarction predict increased risk of death or recurrent myocardial infarction. This work identifies a crucial interaction between mature B lymphocytes and monocytes after acute myocardial ischemia and identifies new therapeutic targets for acute myocardial infarction.This work was supported by Inserm, British Heart Foundation (Z.M.), European Research Council (Z.M.), Fondation Coeur et Recherche (Z.M., T.S., N.D.), Fondation pour la Recherche Medicale (J.S.S.), European Union Seven Framework programme TOLERAGE (Z.M.), Fondation Leducq transatlantic network (C.J.B., D.T., A.T., J.S.S., Z.M.), National Institutes of Health grants AI56363 and AI057157, and a grant from The Lymphoma Research Foundation (T.F.T).This is the author accepted manuscript. The final version is available from Nature Publishing Group at http://dx.doi.org/10.1038/nm.3284

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació