Arts et Métiers ParisTech

About: Arts et Métiers ParisTech is a education organization based out in Paris, France. It is known for research contribution in the topics: Finite element method & Machining. The organization has 3946 authors who have published 6693 publications receiving 142083 citations. The organization is also known as: École nationale supérieure d'arts et métiers & ENSAM.

Genetic diversity in the coat protein coding region of eighty-six sugarcane mosaic virus isolates from eight countries, particularly from Cameroon and Congo.

Abstract: Fifty-eight sugarcane virus isolates were obtained from leaves showing mosaic symptoms, and collected in Cameroon (26 isolates), Congo (20 isolates), Egypt (1 isolate), South Africa (3 isolates) and the U.S.A. (8 isolates). All these isolates belonged to Sugarcane mosaic virus (SCMV) based on the amplification product obtained by RT-PCR with SCMV-specific primers. The amplicons (0.9 kb) from the coat protein (CP) coding region were cloned, sequenced and compared to each other as well as to the sequences (GenBank accessions) of 16 SCMV isolates from sugarcane (Australia, South Africa and U.S.A.) and 12 SCMV isolates from maize (Australia, Germany and China). Maximum likelihood and maximum parsimony analyses robustly supported two major monophyletic groups that were correlated with the host of origin: the SCE or sugarcane group that included all isolates from sugarcane and the MZ or maize group that contained all isolates from maize. The 86 virus isolates were distributed in 13 minor phylogenetic groups, four (I–IV) restricted to maize and nine (V–XIII) to sugarcane. A strong correlation was observed between the sugarcane groups and the geographical origin of the SCMV isolates. Each SCMV type strain from sugarcane (A, B, D, E and SC) was distributed in a different phylogenetic group or subgroup. The 26 isolates from Cameroon constituted a relatively homogenous group (group V) whereas the 20 isolates from Congo belonged to two other groups (VI and VII). All the isolates from Cameroon and Congo were different from the SCMV type strains and other strains or isolates studied so far. It appears, therefore, that the population of SCMV from sugarcane in Africa contains virus genotypes that have not yet been described.

On the Reduction of Kinetic Theory Models Related to Finitely Extensible Dumbbells

Abstract: Stochastic simulation for finitely extensible non-linear elastic (FENE) dumbbells has been successfully applied (seethe review paper of Keunings [R. Keunings, Micro-macro methods for the multiscale simulation viscoelastic flow using molecular models of kinetic theory, in: D.M. Binding, K. Walters (Eds.), Rheology Reviews, British Society of Rheology, 2004, pp. 67-98] and the references therein). The main difficulty in these simulations is related to the high number of realizations required for describing accurately the microstructural state due to Brownian effects. The discretisation of the Fokker-Planck equation with a mesh support (finite elements, finite differences, finite volumes, spectral techniques,...) allows to go beyond the difficulty related to Brownian effects. However, kinetic theory models involve physical and conformation spaces. Thus, the molecular distribution depends on time, space as well as on the molecular orientation and extension (conformation coordinates). In this form the resulting Fokker-Planck equation is defined in a space of dimension 7. In the reduction technique proposed in this paper, a reduced approximation basis is constructed. The new shape functions are defined in the whole domain in an appropriate manner. Thus, the number of degrees of freedom involved in the solution of the Fokker-Planck equation is significantly reduced. The construction of those new approximation functions is done with an 'a priori' approach, which combines a basis reduction (using the Karhunen-Loeve decomposition) with a basis enrichment based on the use of some Krylov subspaces. This numerical technique is applied for solving the FENE model of viscoelastic flows. (c) 2006 Elsevier B.V. All rights reserved.