Existence of global Solutions to the 1D Abstract Bubble Vibration Model

27 pagesInternational audienceThe Abstract Bubble Vibration model (Abv) is a set of two PDEs consisting of a transport equation and a Poisson equation. It has been derived in order to provide a better understanding of hyperbolic-elliptic couplings which are involved in a more general low Mach number system modelling bubbles. While a local existence theorem has already been proven in any dimension for the Abv model, we get interested in this paper in the one-dimensional case, where we prove the existence of global solutions no matter how smooth the data. We also provide explicit expressions of the solutions by means of the method of characteristics that we apply to the transport equation despite the coupling with the Poisson equation. We then compute these solutions by means of a numerical scheme based on a discrete version of the method of characteristics

Coupling strategies for compressible - low Mach number flows

International audienceIn order to enrich the modelling of fluid flows, we investigate in this paper a coupling between two models dedicated to distinct regimes. More precisely, we focus on the influence of the Mach number as the low Mach case is known to induce theoretical and numerical issues in a compressible framework. A moving interface is introduced to separate a compressible model (Euler with source term) and its low Mach counterpart through relevant transmission conditions. A global steady state for the coupled problem is exhibited. Numerical simulations are then performed to highlight the influence of the coupling by means of a robust numerical strategy

Ethylene Production in Spinach Leaves during Floral Induction

Spinach plants were induced to flower by transferring them from short days to continuous light. Their leaf laminae released more ethylene than those from vegetative plants. These leaves also exhibited a greater capacity to convert exogenous ACC into ethylene. Cell wall preparations from the leaves of continuously illuminated plants also converted exogenous ACC into ethylene more readily than extracts from short day plants. These effects and also those previously reported for peroxidases appear very similar to these brought about by various environmental stresses such as pollution and mechanical irritatio

Polymorphix: a sequence polymorphism database

Within-species sequence variation data are of special interest since they contain information about recent population/species history, and the molecular evolutionary forces currently in action in natural populations. These data, however, are presently dispersed within generalist databases, and are difficult to access. To solve this problem, we have developed Polymorphix, a database dedicated to sequence polymorphism. It contains within-species homologous sequence families built using EMBL/GenBank under suitable similarity and bibliographic criteria. Polymorphix is an ACNUC structured database allowing both simple and complex queries for population genomic studies. Alignments within families as well as phylogenetic trees can be download. When available, outgroups are included in the alignment. Polymorphix contains sequences from the nuclear, mitochondrial and chloroplastic genomes of every eukaryote species represented in EMBL. It can be accessed by a web interface (http://pbil.univ-lyon1.fr/polymorphix/query.php)