Évènements Rares sur des Séries Temporelles Environnementales

International audienceLa mesure de l'activité de mollusques bivalves est un moyen d'enregistrer le comportement de bivalves in situ et donc d'évaluer des changements de la qualité de l'eau. Nous proposons une méthode statistique basée sur la théorie des valeurs extrêmes permettant d'estimer des changements globaux (pollution, changement de température) et ainsi d'aider à la surveillance de systèmes aquatiques

Polarized Dirac fermions in de Sitter spacetime

The tetrad gauge invariant theory of the free Dirac field in two special moving charts of the de Sitter spacetime is investigated pointing out the operators that commute with the Dirac one. These are the generators of the symmetry transformations corresponding to isometries that give rise to conserved quantities according to the Noether theorem. With their help the plane wave spinor solutions of the Dirac equation with given momentum and helicity are derived and the final form of the quantum Dirac field is established. It is shown that the canonical quantization leads to a correct physical interpretation of the massive or massless fermion quantum fields.Comment: 19 pages, LaTeX w AMS sym

The modelling of creep for engineering design-1

SIGLEAvailable from British Library Document Supply Centre- DSC:6029.3292(NPL-DMA(A)--115) / BLDSC - British Library Document Supply CentreGBUnited Kingdo