429 research outputs found

    Achieving an optimal trade-off between revenue and energy peak within a smart grid environment

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    We consider an energy provider whose goal is to simultaneously set revenue-maximizing prices and meet a peak load constraint. In our bilevel setting, the provider acts as a leader (upper level) that takes into account a smart grid (lower level) that minimizes the sum of users' disutilities. The latter bases its decisions on the hourly prices set by the leader, as well as the schedule preferences set by the users for each task. Considering both the monopolistic and competitive situations, we illustrate numerically the validity of the approach, which achieves an 'optimal' trade-off between three objectives: revenue, user cost, and peak demand

    Prédisposition génétique à l'hypertension de grossesse : polymorphismes de gènes de la détoxication

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    L'hypertension de grossesse (HG) se retrouve chez 5 à 10% des femmes enceintes. Son étiologie demeure inconnue à ce jour, mais sa physiopathologie impliquerait une perfusion sanguine abaissée de l'unité foeto-maternelle entraînant un stress oxydatif suivi d'une dysfonction de l'endothélium vasculaire maternel. Nos travaux de recherche visent l'identification des facteurs génétiques liés au stress oxydatif et pouvant prédisposer à l'HG chez la femme. Dans ce but, nous avons évalué certains polymorphismes de gènes impliqués dans la biotransformation des dérivés actifs de l'oxygène et des xénobiotiques : glutathion S-transférase pi (GSTP1), mu (GSTM1) et thêta (GSTT1) ; cytochrome p450 (CYP1A1), époxyde hydrolase (EPXH), NO-synthase endothéliale (eNOS), catalase (CAT) et superoxyde dismutase (MnSOD). Notre étude a permis de mettre en évidence quatre polymorphismes associés au risque d'HG et/ou de prééclampsie (PE) : GST[pi] A313 [313 en exposant]G (RC= 0.42 IC 95% [0.22-0.80]) ; GSTM1dél [dél en exposant] (RC= 0.26 [0.07-0.91]) ; eNOS G849 [849 en exposant]T (RC = 3.19 [1.33-7.67]) ainsi que CAT G-844 [-844 en exposant]A (RC= 0.24 [0.07-0.85]). Nos résultats montrent également plusieurs associations d'allèles indépendants combinés deux à deux prédictives d'un risque d'HG. En corollaire, certains marqueurs génétiques d'enzymes impliquées dans la biotransformation pourraient permettre d'identifier précocement les femmes à risque d'HG et pourraient avoir des implications sur le risque de maladies cardiovasculaires à long terme

    Bilevel Modelling of Energy Pricing Problem

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    International audienceCost minimization problem of a smart grid operator is integrated into the revenue optimization problem of an energy provider. Bilevel programming approach is applied to model the problem. The results of a classical exact method and two heuristic methods are compared

    Accelerated Evolution of Mitochondrial but Not Nuclear Genomes of Hymenoptera: New Evidence from Crabronid Wasps

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    Mitochondrial genes in animals are especially useful as molecular markers for the reconstruction of phylogenies among closely related taxa, due to the generally high substitution rates. Several insect orders, notably Hymenoptera and Phthiraptera, show exceptionally high rates of mitochondrial molecular evolution, which has been attributed to the parasitic lifestyle of current or ancestral members of these taxa. Parasitism has been hypothesized to entail frequent population bottlenecks that increase rates of molecular evolution by reducing the efficiency of purifying selection. This effect should result in elevated substitution rates of both nuclear and mitochondrial genes, but to date no extensive comparative study has tested this hypothesis in insects. Here we report the mitochondrial genome of a crabronid wasp, the European beewolf (Philanthus triangulum, Hymenoptera, Crabronidae), and we use it to compare evolutionary rates among the four largest holometabolous insect orders (Coleoptera, Diptera, Hymenoptera, Lepidoptera) based on phylogenies reconstructed with whole mitochondrial genomes as well as four single-copy nuclear genes (18S rRNA, arginine kinase, wingless, phosphoenolpyruvate carboxykinase). The mt-genome of P. triangulum is 16,029 bp in size with a mean A+T content of 83.6%, and it encodes the 37 genes typically found in arthropod mt genomes (13 protein-coding, 22 tRNA, and two rRNA genes). Five translocations of tRNA genes were discovered relative to the putative ancestral genome arrangement in insects, and the unusual start codon TTG was predicted for cox2. Phylogenetic analyses revealed significantly longer branches leading to the apocritan Hymenoptera as well as the Orussoidea, to a lesser extent the Cephoidea, and, possibly, the Tenthredinoidea than any of the other holometabolous insect orders for all mitochondrial but none of the four nuclear genes tested. Thus, our results suggest that the ancestral parasitic lifestyle of Apocrita is unlikely to be the major cause for the elevated substitution rates observed in hymenopteran mitochondrial genomes

    Bilevel Programming

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    Novel Approaches To The Discrimination Problem

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    this paper we follow an altogether different approach (see also Cavalier et al. [3]). We do not assume any functional form for the distributions FX and F Y . Actually we do not even assume the points
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