Sublethal effects of a metal contamination due to uranium mine tailings in the three-spined stickleback (Gasterosteus aculeatus L.). Implication in the susceptibility to a biological stress.

L’extraction de l’uranium a eu pour conséquence une remobilisation de cet actinide au niveau des écosystèmes avoisinants les mines. L’utilisation de sels métalliques lors de la réhabilitation des sites miniers et la présence naturelle de métaux ont accentué les niveaux de la contamination métallique dans les hydrosystèmes soumis aux rejets miniers uranifères.Des expériences in situ ont été conduites au niveau de deux anciens sites miniers uranifères français. L’encagement de l’épinoche à trois épines a été employé pour connaître les effets sublétaux de ce mélange métallique, ainsi que sur la susceptibilité de ce poisson envers un stress biologique.Cette pollution, caractérisée par de plus importantes concentrations métalliques (notamment en uranium), a entraîné un stress oxydant chez l’épinoche visible sur plusieurs biomarqueurs, ainsi que d’autres effets dépendants du site d’exposition.La contamination polymétallique a occasionné une augmentation de la susceptibilité des épinoches au stress biologique, en empêchant leurs réponses phagocytaire antioxydante à ce stress. Ces travaux ont permis de renforcer l’intérêt de la technique d’encagement lors d’une étude environnementale, et celui des immunomarqueurs au sein d’une approche multi-biomarqueurs.Uranium extraction has resulted in a remobilisation of this actinide into mine surrounding ecosystems. Uses of metal salts during mining site rehabilitation, and the natural presence of metals have increased the metal contamination in hydrosystems submitted to mine tailings.In situ experiments were conducted in two former French uranium mining sites. Three-spined stickleback caging was used to determine the sublethal effects of this metal mixture on this freshwater fish, as well as its effects on fish susceptibility to a sudden biological stress.This pollution, characterised by higher metal concentrations (especially for uranium), has led to an oxidative stress in sticklebacks visible through several biomarkers, and other effects dependent on the study site. The polymetallic contamination has modified the stickleback responses to the biological stress, by preventing their phagocytic and antioxidant responses. This work has reinforced the interest of the caging technique during environmental studies and that of immunomarkers in a multi-biomarker approach

Reachability Analysis of Hybrid Systems using Support Functions

Abstract. This paper deals with conservative reachability analysis of a class of hybrid systems with continuous dynamics described by linear differential inclusions, convex invariants and guards, and linear reset maps. We present an approach for computing over-approximations of the set of reachable states. It is based on the notion of support function and thus it allows us to consider invariants, guards and constraints on continuous inputs and initial states defined by arbitrary compact convex sets. We show how the properties of support functions make it possible to derive an effective algorithm for approximate reachability analysis of hybrid systems. We use our approach on some examples including the navigation benchmark for hybrid systems verification

Zonotope/hyperplane intersection for hybrid systems reachability analysis

International audienceIn this paper, we are concerned with the problem of computing the reachable sets of hybrid systems with (possibly high dimensional) linear continuous dynamics and guards defined by switching hyperplanes. For the reachability analysis of the continuous dynamics, we use an efficient approximation algorithm based on zonotopes. In order to use this technique for the analysis of hybrid systems, we must also deal with the discrete transitions in a satisfactory (i.e. scalable and accurate) way. For that purpose, we need to approximate the intersection of the continuous reachable sets with the guards enabling the discrete transitions. The main contribution of this paper is a novel algorithm for computing efficiently a tight over-approximation of the intersection of (possibly high-order) zonotopes with a hyperplane. We show the accuracy and the scalability of our approach by considering two examples of reachability analysis of hybrid systems

Efficient reachability analysis for linear systems using support functions

International audienceThis work is concerned with the algorithmic reachability analysis of linear systems with constrained initial states and inputs. In this paper, we present a new approach for the computation of tight polyhedral over-approximations of the reachable sets of a linear system. The main contribution over our previous work is that it makes it possible to consider systems whose sets of initial states and inputs are given by arbitrary compact convex sets represented by their support functions. We first consider the discrete-time setting and then we show how our algorithm can be extended to handle continuous-time linear systems. Finally, the effectiveness of our approach is demonstrated through several examples

De la géologie du Quaternaire à la géotechnique

Civil Engineering Geology depends largely upon Quaternary Geology, which determines many important properties of a terrain from the viewpoint of construction or utilisation. An attempt is made to list the items where properties of soils and rocks are revealed by an accurate knowledge of their particular history during recent times. Any further progress in that matter will be useful in increasing the success of our undertakings related to ground control and management.La Géologie du Quaternaire apporte une contribution importante à la Geotechnique en lui fournissant de très nombreuses données utilisables avec profit. La présente note tente de classer les diverses occasions ou une connaissance préecise de l'histoire des événements récents fournit des clartés sur les aptitudes ou les défauts techniques des sols et des roches. Tout progrès en cette matière sera certainement bénéfique pour la réussite des projets concernant les travaux de génie civil et l'aménagement du territoire.Letourneur J., Antoine Pierre, Le Guernic J. De la géologie du Quaternaire à la géotechnique. In: Bulletin de l'Association française pour l'étude du quaternaire, vol. 18, n°1, 1981. pp. 27-32

Calcul d'atteignabilité des systèmes hybrides à partie continue linéaire

Cette thèse est consacrée au calcul des états atteignables des systèmes linéaires et hybrides. La première partie est consacrée aux systèmes linéaires. Après avoir présenté les méthodes existantes, nous introduisons notre principale contribution: un nouveau schéma algorithmique pour l'analyse d'accessibilité des systèmes linéaires invariants qui surclasse nettement les algorithmes existants. Une implémentation exacte peut produire des ensembles difficiles à manipuler, nous proposons donc une version produisant une sur-approximation non soumise à l'effet d'emballage, une accumulation incontrôlée des erreurs d'approximation, ainsi qu'une variante dédiée aux fonctions support, une représentation fonctionnelle des ensembles convexes. La deuxième partie adapte ces résultats aux systèmes hybrides. Nous montrons d'abord comment gérer les invariants, avant de nous intéresser à l'approximation de l'intersection entre l'ensemble atteignable par la dynamique continue et des gardes hyperplanaires.This thesis is devoted to the problem of computing reachable sets of linear and hybrid systems. In the first part, after exposing existing approaches for reachability analysis of linear systems, we present the main contribution of the thesis: a new algorithmic scheme for linear time-invariant systems that definitely outperforms existing algorithms. As the exact implementation furnishes a representation of the reachable sets that is sometimes hard to manipulate, we propose an approximate version that is not subject to the wrapping effect, an uncontrolled growth of the approximation errors. We also discuss a variant of this algorithm specialized to support functions, a functional representation of convex sets. In the second part, we extend this work to hybrid systems. We first show how to deal with the constraints on the continuous dynamics imposed by the invariants. Then, we present algorithms for approximating the intersection of the continuous reachable sets with hyperplanar guards.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Evaluation des capacités de défenses immunitaires et de leur acclimatation dans un contexte de contamination polymétallique chez l'épinoche a trois épines (Gasterosteus aculeatus)

TesisLima NorteEscuela de PosgradoGestión y Calidad EducativaLa presente investigación titulada “Gestión administrativa y resolución de conflictos en los institutos de educación superior pedagógica públicos de Lima” considera dentro de su objetivo general, es determinar la relación existente en ambas variables. El método de investigación tiene un enfoque cuantitativo y de tipo básica, de diseño no experimental, transversal – correlacional. La población fue de 70 profesores y de modo similar la muestra, siendo de tipo no probabilística; la técnica que se utilizó fue la encuesta y como instrumento de investigación, el cuestionario que cumplió con los requisitos de validez y la confiabilidad. El método que se utilizó fue el hipotético deductivo, para el análisis de datos se aplicó la prueba no paramétrica Rho de Spearman. Los resultados de la investigación demuestran la relación entre la gestión administrativa y resolución de conflictos. En cuanto al grado de correlación se determinó, que existe correlación alta positiva entre las variables (Rho de Spearman = 0.828), siendo el p valor significativo (p = 0.000 < 0.05)

Comparison of viability and phagocytic responses of hemocytes withdrawn from the bivalves Mytilus edulis and Dreissena polymorpha, and exposed to human parasitic protozoa

International audienceBivalve molluscs are now considered indicator species of aquatic contamination by human parasitic protozoa. Nonetheless, the possible effects of these protozoa on the immune system of their paratenic hosts are poorly documented. The aim of this study was to evaluate the effects of two protozoa on hemocyte viability and phagocytosis from two mussels, the zebra mussel (freshwater habitat) and the blue mussel (seawater habitat). For these purposes, viability and phagocytic markers have been analysed on hemocytes from mussels without biological stress (control hemocytes), and on hemocytes exposed to a biological stress (Toxoplasma gondii and Cryptosporidium parvum oocysts). We report, for the first known time, the interactions between protozoa and hemocytes of mussels from different aquatic environments. Zebra mussel hemocytes showed a decrease in phagocytosis of fluorescent microbeads after exposure to both protozoa, while blue mussel hemocytes reacted only to T. gondii oocysts. These decreases in the ingestion of microbeads can be caused by competition between beads and oocysts and can be influenced by the size of the oocysts. New characterisations of their immune capacities, including aggregation, remain to be developed to understand the specificities of both mussels