Quasi-perpendicular fast magnetosonic shock with wave precursor in collisionless plasma

A one-dimensional particle-in-cell (PIC) simulation tracks a fast magnetosonic shock over time scales comparable to an inverse ion gyrofrequency. The magnetic pressure is comparable to the thermal pressure upstream. The shock propagates across a uniform background magnetic field with a pressure that equals the thermal pressure upstream at the angle 85$^\circ$ at a speed that is 1.5 times the fast magnetosonic speed in the electromagnetic limit. Electrostatic contributions to the wave dispersion increase its phase speed at large wave numbers, which leads to a convex dispersion curve. A fast magnetosonic precursor forms ahead of the shock with a phase speed that exceeds the fast magnetosonic speed by about $\sim 30 \%$. The wave is slower than the shock and hence it is damped.Comment: 4 pages, 3 figure

Vers un système générique de réécriture de graphes pour l'enrichissement de structures syntaxiques.

National audienceCe travail présente une nouvelle approche pour injecter des dépendances profondes (sujet des verbes à contrôle, partage du sujet en cas d'ellipses, . . .) dans un corpus arboré présentant un schéma d'annotation surfacique et projectif. Nous nous appuyons sur un système de réécriture de graphes utilisant des techniques de programmation par contraintes pour produire des règles génériques qui s'appliquent aux phrases du corpus. Par ailleurs, nous testons la généricité des règles en utilisant des sorties de trois analyseurs syntaxiques différents, afin d'évaluer la dégradation exacte de l'application des règles sur des analyses syntaxiques prédites

Regulation of telomere addition at DNA double-strand breaks

Telomeres constitute the ends of linear eukaryotic chromosomes. Due to the conventional mode of DNA replication, telomeric DNA erodes at each cell division. To counteract this, a specialized reverse transcriptase, telomerase, can elongate chromosome ends to maintain them at a constant average length. Because of their similarity to DNA double-strand breaks (DSBs), telomeres might be expected to induce a DNA damage response, which would lead to repair reactions and the generation of translocations or fusions. Many proteins present at telomeres prevent this by protecting (capping) the chromosome termini. Conversely, a DSB occurring in other regions of the genome, due, for instance, to a stalled replication fork or genotoxic agents, must be repaired by homologous recombination or end-joining to ensure genome stability. Interestingly, telomerase is able to generate a telomere de novo at an accidental DSB, with potentially lethal consequences in haploid cells and, at a minimum, loss of heterozygosity (LOH) in diploid cells. Recent data suggest that telomerase is systematically recruited to DSBs but is prevented from acting in the absence of a minimal stretch of flanking telomere-repeat sequences. In this review, we will focus on the mechanisms that regulate telomere addition to DSB

Semi-Automatic Deep Syntactic Annotations of the French Treebank

International audienceWe describe and evaluate the semi-automatic addition of a deep syntactic layer to the French Treebank (Abeillé and Barrier [1]), using an existing scheme (Candito et al. [6]). While some rare or highly ambiguous deep phenomena are handled manually, the remainings are derived using a graph-rewriting system (Ribeyre et al. [22]). Although not manually corrected, we think the resulting Deep Representations can pave the way for the emergence of deep syntactic parsers for French