102 research outputs found
The scope of the crustacean immune system for disease control
The culture or wild capture of marine and freshwater shellfish, including crustaceans, is without doubt a key source of protein for a burgeoning world population. Historically the expansion of aquaculture has, however, been accompanied by the increased incidence of economically significant diseases, most notably of viral and bacterial origin. Since the late 1970s great progress has been made in our understanding of the generalized protostome innate immune system. Distinct pathways, pathogen receptor proteins and effector molecules have since been identified that are not ancestral or homologous to those of the deuterostomes, including vertebrates. Within the past decade progress has accelerated with the rapid characterisation of new classes of recognition proteins, immune effectors and regulatory pathways. This paper provides a broad overview of our current understanding of invertebrate immunology, taking the crustacean decapod immune system as its focus. Recent developments in the field are described briefly and their implications and potential considered. These advances offer fundamental new insights in our efforts to understand disease in cultured populations and also to develop knowledge of environmental effects on host/pathogen interactions within a fishery context. Of course, challenges do remain, including the lack of an immortal cell line and the limited publically-available genomic resources. These are considered in this review as priorities for future research effort. With the continued application of more insightful technologies, coupled with associated investment, it is expected that the speed at which some of these issues are resolved will accelerate
White spot syndrome virus: an overview on an emergent concern
Viruses are ubiquitous and extremely abundant in the marine environment. One of such marine viruses, the white spot syndrome virus (WSSV), has emerged globally as one of the most prevalent, widespread and lethal for shrimp populations. However, at present there is no treatment available to interfere with the unrestrained occurrence and spread of the disease. The recent progress in molecular biology techniques has made it possible to obtain information on the factors, mechanisms and strategies used by this virus to infect and replicate in susceptible host cells. Yet, further research is still required to fully understand the basic nature of WSSV, its exact life cycle and mode of infection. This information will expand our knowledge and may contribute to developing effective prophylactic or therapeutic measures. This review provides a state-of-the-art overview of the topic, and emphasizes the current progress and future direction for the development of WSSV control strategies
Photolysis Kinetics, Mechanisms, and Pathways of Tetrabromobisphenol A in Water under Simulated Solar Light Irradiation
Intériorisations de l'inventio crucis dans la France du XVIIe siècle (jusque vers 1660)
La croisade était pèlerinage collectif pour la découverte de la croix. Elle n’est plus possible au XVIIe siècle. L’invention de la croix est intériorisée par la dévotion moderne dans la France du XVIIe siècle. C’est une négation de la Croisade comme mouvement « panique » d’extériorisation vers l’Orient, selon A. Dupront. Mais la conversion spirituelle devient comme un modèle pour la société du temps. La négation est ainsi niée à son tour dans la société catholique française du milieu du XVIIe siècle.A crusade was a collective pilgrimage for inventio crucis or the discovery of the true cross. This was no longer permitted in 17th century France where the inventio crucis was transformed by a devotio moderna and disallowed as a crisis movement in the East according to A. Dupront. But it remained alive through its spiritual conversion that became a model of French Catholic society in the 17th century
Méthodes de capture de chocs instationnaires et leur implémentation pour la méthode des éléments finis
RÉSUMÉ Ce mémoire s’intéresse à la stabilisation des écoulements pouvant présenter des discontinui- tés et des chocs, notamment les écoulements compressibles. La simulation des équations de Navier-Stokes avec la méthode des éléments finis peut présenter des instabilités, c’est pour- quoi de nombreux schémas de stabilisation ont vu le jour, comme SUPG (Streamline-Upwind Petrov Galerkin). En présence de chocs, des oscillations supplémentaires apparaissent, il est nécessaire de mettre en place de la capture de choc pour les atténuer. Nous utilisons une formulation unifiée des équations de Navier-Stokes, en variables primi- tives. De cette façon, les équations sont définies pour les écoulements compressibles comme incompressibles, ce qui nous permet de chercher à implémenter une capture de choc univer- selle, qui fonctionne pour tout type d’écoulements laminaires. Après avoir adapté de la littérature deux opérateurs de capture de choc s’ajoutant à SUPG, nous avons évalué leurs performances sur deux cas tests : un cas de convection-diffusion et un tube à choc. Chacune des deux méthodes apporte une amélioration des résultats, bien qu’elle s’accompagne de difficultés de convergence lors de la résolution du système d’équations. De plus, les méthodes ne sont efficaces que pour un cas test donné chacune, et non les deux. Les sources de la plupart des difficultés rencontrées ont été identifiées. Ainsi des suggestions pour l’amélioration de la précision des méthodes et pour une meilleure universalisation ont pu être proposées.----------ABSTRACT This work is devoted to the stabilization of flows that may present discontinuities and shocks, in particular compressible flows. The simulation of the Navier-Stokes equations with the finite element method can present instabilities. To prevent that, many stabilization schemes have been developed, such as SUPG (Streamline-Upwind Petrov Galerkin). When shocks are involved, additional oscillations appear, we need to add shock capture to dampen them. We use a unified formulation of the Navier-Stokes equations, in primitive variables. This way, the equations are defined for both compressible and incompressible flows, which allows us to try to implement a universal shock capture, which will work for all types of laminar flows. After adapting from the literature two shock capture methods in combination with SUPG, we have evaluated their performances on two test cases: a convection-diffusion case and a shock tube. Each of the two methods brings an improvement of the results, although they are affected by convergence difficulties when solving the system of equations. Moreover, the methods are only effective for one given test case each, not both. The sources of most of the difficulties encountered have been identified. Thus, suggestions for improving the accuracy of the methods and for a better generalization have been proposed
Traversée adolescente et rencontre de l’objet
Nous émettons l’hypothèse que le recours à l’homoérotisme à l’adolescence constitue une pièce maîtresse dans le cheminement qui mène à la rencontre de l’objet en revêtant plusieurs fonctions. Mais ce recours peut buter sur le travail de perte que toute adolescence exige. Nous déploierons les spécificités de ce recours et ses potentiels empêchements dans le développement psychosexuel du garçon. Nous mettrons ces éléments à l’épreuve, à partir du roman « Call me by your name » d’André Aciman (2007
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