1,078 research outputs found

    Genetic Testing for Breast and Ovarian Cancer: Implications for Life Insurance

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    As the science of genetic testing progresses, the debate surrounding the uses of genetic information intensifies. In February, President Clinton signed an executive order prohibiting federal agencies from using such information to make hiring, promotion, or placement decisions. Concerns about privacy and discrimination have led many states to propose or enact statutes that prohibit health insurers from using genetic test results in their underwriting decisions. However, few statutes address access to these results by the life insurance industry. This Issue Brief summarizes the current debate on whether life insurers should have access to genetic testing information for breast and ovarian cancer, and provides actuarial insight into the potential effect of such testing on the voluntary term insurance market

    Branch and Bound hybride pour un problème de job-shop soumis à des contraintes de ressources humaines

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    National audienceNous considérons un problème couplant ordonnancement de production et planification d'agents. On se place ainsi dans un atelier où la production à réaliser requiert divers types de machines dans des séquences variées de type job-shop. Chaque machine nécessite pour son utilisation la présence d'un employé qualifié à son pilotage. Les ressources humaines sont assujetties à des contraintes légales restreignant leur disponibilité. La production doit être entièrement ordonnancée et le critère d'optimisation retenu est la minimisation des coûts salariaux. Pour résoudre ce problème, nous avons développé une méthode exacte hybridant approche arborescente de type Procédure de Séparation et Evaluation Séquentielle et technique de génération de coupes de réalisabilité. Cette méthode exploite la décomposition naturelle du problème global en deux sous-problèmes : un problème de planification d'agents et un problème de job-shop à contraintes de disponibilité. Des méthodes de génération d'inégalités valides en pré-process (notamment du probing) ont en outre été étudiées. Notre approche s'avère particulièrement adaptée à la problématique ; ses résultats dominent en effet ceux obtenus avec l'un des meilleurs solveurs commerciaux actuels (Ilog Cplex 12.1) et ceux obtenus avec les méthodes décrites dans la littérature

    Cut generation for an integrated employee timetabling and production scheduling problem

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    International audienceThis paper investigates the integration of the employee timetabling and production scheduling problems. At the first level, we manage a classical employee timetabling problem. At the second level, we aim at supplying a feasible production schedule for a set of interruptible tasks with qualification requirements and time-windows. Instead of hierarchically solving these two problems as in the current practice, we try here to integrate them and propose two exact methods to solve the resulting problem. The former is based on a Benders decomposition while the latter relies on a specific decomposition and a cut generation process. The relevance of these different approaches is discussed here through experimental results

    Couplage planification/ordonnancement : une approche par décomposition et génération de coupes.

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    International audienceCette étude porte sur un problème couplant les deux phases décisionnelles, dans un processus de production, que sont la planification d'agents et l'ordonnancement de production. D'un côté, nous devons gérer au moindre coût les emplois du temps d'un ensemble d'opérateurs (planification d'agents) et de l'autre, nous nous attelons à fournir un plan de production réalisable, compte tenu des ressources disponibles déduites de la phase de planification, et qui vise à satisfaire une certaine demande fournie en entrée (ordonnancement de production). Contrairement à la plupart des articles de la littérature, nous proposons ici des techniques de résolution résolvant simultanément ces deux problèmes. Deux approches exactes ont été étudiées : l'une d'elles est fondée sur une décomposition de Benders et l'autre est basée sur un processus spécifique de génération de coupes. L'intérêt de ces méthodes est discuté ici au travers de résultats expérimentaux

    Solving an integrated job-shop problem with human resource constraints

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    International audienceWe propose two exact methods to solve an integrated employee-timetable and job-shop-scheduling problem. The problem is to find a minimum cost employee-timetable, where employees have different competences and work during shifts, so that the production, that corresponds to a job-shop with resource availability constraints, can be achieved. We introduce two new exact procedures: (1) a decomposition and cut generation approach and (2) a hybridization of a cut generation process with a branch and bound strategy. We also propose initial cuts that strongly improve these methods as well as a standard MIP approach. The computational performances of those methods on benchmark instances are compared to that of other methods from the literature

    Solving an integrated Job-Shop problem with human resource constraints

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    This paper investigates the integration of the employee timetabling and production scheduling problems. At the first level, we have to manage a classical employee timetabling problem. At the second level, we aim at supplying a feasible production schedule for a job-shop scheduling problem (NP-hard problem). Instead of using a hierarchical approach as in the current practice, we here integrate the two decision stages and propose two exact methods for solving the resulting problem. The former is similar to the cut generation algorithm proposed in Guyon et. al. 2010) for a problem integrating a classical employee timetabling problem and a polynomially solvable production scheduling problem. The latter is based on a Branch-And-Cut process that exploits the same feasibility cuts than the first approach. Preliminar experimental results on instances proposed in (Artigues et al. 2009) reveal a real interest for the approaches described here

    Planification d'agents et ordonnancement de production : règles d'élimination et heuristique

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    Nous nous intéressons à l'optimisation des systèmes de production avec d'un côté l'ordonnancement de production, dont le but est d'affecter dans le temps des ressources à des tâches à réaliser, et d'un autre côté la gestion du personnel visant généralement à minimiser les coûts de main d'œuvre. Bien qu'il soit admis que, pour obtenir l'optimum global, il faille prendre en compte simultanément ces deux problématiques, en pratique le problème global est souvent résolu dans un processus de décision à deux niveaux. Dans cette étude, nous intégrons ces deux phases de décision et proposons différentes méthodes pour résoudre le problème résultant

    Alain Huck. Drawing History.

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    Active since the mid-eighties, Alain Huck is a Swiss artist born in 1957. After having explored various media in sculptures and small paintings, from 1993 to 2007, he kept a personal diary of 269 drawings entitled Vite soyons heureux il le faut je le veux (“Quick, let’s be happy, we must, I want it”: henceforth referred to as VSH), in which he found material for his latter works. Since 2006 he has been using charcoal for monumental works on paper which depict forests and – as studied in this ..

    Type III secretion proteins PcrV and PcrG from Pseudomonas aeruginosa form a 1:1 complex through high affinity interactions

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    BACKGROUND: Pseudomonas aeruginosa, an increasingly prevalent opportunistic pathogen, utilizes a type III secretion system for injection of toxins into host cells in order to initiate infection. A crucial component of this system is PcrV, which is essential for cytotoxicity and is found both within the bacterial cytoplasm and localized extracellularly, suggesting that it may play more than one role in Pseudomonas infectivity. LcrV, the homolog of PcrV in Yersinia, has been proposed to participate in effector secretion regulation by interacting with LcrG, which may act as a secretion blocker. Although PcrV also recognizes PcrG within the bacterial cytoplasm, the roles played by the two proteins in type III secretion in Pseudomonas may be different from the ones suggested for their Yersinia counterparts. RESULTS: In this work, we demonstrate by native mass spectrometry that PcrV and PcrG expressed and purified from E. coli form a 1:1 complex in vitro. Circular dichroism results indicate that PcrG is highly unstable in the absence of PcrV; in contrast, both PcrV alone and the PcrV:PcrG complex have high structural integrity. Surface plasmon resonance measurements show that PcrV interacts with PcrG with nanomolar affinity (15.6 nM) and rapid kinetics, an observation which is valid both for the full-length form of PcrG (residues 1–98) as well as a form which lacks the C-terminal 24 residues, which are predicted to have low secondary structure content. CONCLUSIONS: PcrV is a crucial component of the type III secretion system of Pseudomonas, but the way in which it participates in toxin secretion is not understood. Here we have characterized the interaction between PcrV and PcrG in vitro, and shown that PcrG is highly unstable. However, it associates readily with PcrV through a region located within its first 74 amino acids to form a high affinity complex. The fact that PcrV associates and dissociates quickly from an unstable molecule points to the transient nature of a PcrV:PcrG complex. These results are in agreement with analyses from pcrV deletion mutants which suggest that PcrV:PcrG may play a different role in effector secretion than the one described for the LcrV:LcrG complex in Yersinia
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