345 research outputs found

    Coherence in monoidal track categories

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    We introduce homotopical methods based on rewriting on higher-dimensional categories to prove coherence results in categories with an algebraic structure. We express the coherence problem for (symmetric) monoidal categories as an asphericity problem for a track category and we use rewriting methods on polygraphs to solve it. The setting is extended to more general coherence problems, seen as 3-dimensional word problems in a track category, including the case of braided monoidal categories.Comment: 32 page

    Transition times and stochastic resonance for multidimensional diffusions with time periodic drift: A large deviations approach

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    We consider potential type dynamical systems in finite dimensions with two meta-stable states. They are subject to two sources of perturbation: a slow external periodic perturbation of period TT and a small Gaussian random perturbation of intensity ϵ\epsilon, and, therefore, are mathematically described as weakly time inhomogeneous diffusion processes. A system is in stochastic resonance, provided the small noisy perturbation is tuned in such a way that its random trajectories follow the exterior periodic motion in an optimal fashion, that is, for some optimal intensity ϵ(T)\epsilon (T). The physicists' favorite, measures of quality of periodic tuning--and thus stochastic resonance--such as spectral power amplification or signal-to-noise ratio, have proven to be defective. They are not robust w.r.t. effective model reduction, that is, for the passage to a simplified finite state Markov chain model reducing the dynamics to a pure jumping between the meta-stable states of the original system. An entirely probabilistic notion of stochastic resonance based on the transition dynamics between the domains of attraction of the meta-stable states--and thus failing to suffer from this robustness defect--was proposed before in the context of one-dimensional diffusions. It is investigated for higher-dimensional systems here, by using extensions and refinements of the Freidlin--Wentzell theory of large deviations for time homogeneous diffusions. Large deviations principles developed for weakly time inhomogeneous diffusions prove to be key tools for a treatment of the problem of diffusion exit from a domain and thus for the approach of stochastic resonance via transition probabilities between meta-stable sets.Comment: Published at http://dx.doi.org/10.1214/105051606000000385 in the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

    EXPRESSION OF DEFA1-3 AND RELATIONS WITH RISK FACTORSOF CARDIOVASCULAR DISEASES

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    The infiltration of immuno-inflammatory cells is one of the earliest and durable steps that lead to atherosclerosis. These cells produce many immune components that act as a double-edged sword in this inflammatory disease. Among these components, we note antimicrobial peptides, including defenses. Defenses are natural cationic peptides of the innate immune system. In Humans, these small peptides have a large antimicrobial spectrum. In addition, they play an important role in both infectious and inflammatory diseases. Our objective was to study the relation between alpha-defenses (DEFA) 1-3 genes expression and cardiovascular risk factors. This objective was built on the hypothesis that defenses may be involved in cardiovascular pathologies, and may serve as a new generation of biomarkers. To verify this hypothesis, we treated HL-60 differentiated cells with glucose decreased alphadefenses 1, 2 and 3 gene expression levels, while insulin treatment restored its expression. These findings suggest that DEFA1-3 are involved in the complex glucose-insulin metabolic pathway. In summary, DEFA1-3 genes expression is significantly correlated with glucose. These findings we suggest that DEFA1-3 could be involved in the evolution of cardiovascular complications

    Abstract: EDS case

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    The aim of this paper is to understand and describe what factors and process lead to a relational performance in an outsourcing strategy. Based on the relational view model from Dyer and Singh (1998) and completed by a more processual and learning focused approach, we develop our own descriptive model. This model is applied to the Xerox-EDS outsourcing contract. We then find that our model is quite designed to understand how performance is built. Relational performance is compounded of a gestation performance, a maturation performance and an infiltration performance. Each stage of the relational performance is evaluated on equity and efficiency. In our study, we identify the global process which explain how this performance is built, integrating, for example, how relational specific investments influence learning exchange and how then, shared routines can be created in the relation. So this study helps us to better understand outsourcing as a relational agreement and identify both factors and processes that make this relation evolve and reach the partners goals

    A Toolchain for Grammarians

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    We present a chain of tools used by grammarians and computer scientists to develop grammatical and lexical resources from linguistic knowledge, for various natural languages. The developed resources are intended to be used in Natural Language Processing (NLP) systems.
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