GRAND ÉLÉMENT FINI B14 APPROPRIE A LA RESOLUTION DES PROBLEMES DE MECANIQUE DES SOLS

Les éléments hexaédriques les plus couramment utilisés dans la résolution des problèmes tridimensionnels sont l’élément àhuit noeuds et l’élément à vingt noeuds de la famille de Serendip. L’analyse des solides montre que, l’élément à huit noeuds peutêtre tout à fait rigide dans certains modes de déformation, nécessitant le plus souvent un raffinement important du maillage,tandis que l’utilisation de l’élément à vingt noeuds peut être très coûteuse, car elle implique 60 degrés de liberté et un ordreassez élevé de quadrature pour éviter les modes parasites. Dans cet article, nous allons présenter un élément intermédiaire de lafamille de Serendip à quatorze noeuds nommé B14, ces performances sont évaluées pour des problèmes élastiques etélastoplastiques

Learning nonparametric ordinary differential equations from noisy data

Learning nonparametric systems of Ordinary Differential Equations (ODEs) dot x = f(t,x) from noisy data is an emerging machine learning topic. We use the well-developed theory of Reproducing Kernel Hilbert Spaces (RKHS) to define candidates for f for which the solution of the ODE exists and is unique. Learning f consists of solving a constrained optimization problem in an RKHS. We propose a penalty method that iteratively uses the Representer theorem and Euler approximations to provide a numerical solution. We prove a generalization bound for the L2 distance between x and its estimator and provide experimental comparisons with the state-of-the-art.Comment: 25 pages, 6 figure

Ferulenol specifically inhibits succinate ubiquinone reductase at the level of the ubiquinone cycle

The natural compound ferulenol, a sesquiterpene prenylated coumarin derivative, was purified from Ferula vesceritensis and its mitochondrial effects were studied. Ferulenol caused inhibition of oxidative phoshorylation. At low concentrations, ferulenol inhibited ATP synthesis by inhibition of the adenine nucleotide translocase without limitation of mitochondrial respiration. At higher concentrations, ferulenol inhibited oxygen consumption. Ferulenol caused specific inhibition of succinate ubiquinone reductase without altering succinate dehydrogenase activity of the complex II. This inhibition results from a limitation of electron transfers initiated by the reduction of ubiquinone to ubiquinol in the ubiquinone cycle. This original mechanism of action makes ferulenol a useful tool to study the physiological role and the mechanism of electron transfer in the complex II. In addition, these data provide an additional mechanism by which ferulenol may alter cell function and demonstrate that mitochondrial dysfunction is an important determinant in Ferula plant toxicity