Critical behavior of the two-dimensional N-component Landau-Ginzburg Hamiltonian with cubic anisotropy

We study the two-dimensional N-component Landau-Ginzburg Hamiltonian with cubic anisotropy. We compute and analyze the fixed-dimension perturbative expansion of the renormalization-group functions to four loops. The relations of these models with N-color Ashkin-Teller models, discrete cubic models, planar model with fourth order anisotropy, and structural phase transition in adsorbed monolayers are discussed. Our results for N=2 (XY model with cubic anisotropy) are compatible with the existence of a line of fixed points joining the Ising and the O(2) fixed points. Along this line the exponent $\eta$ has the constant value 1/4, while the exponent $\nu$ runs in a continuous and monotonic way from 1 to $\infty$ (from Ising to O(2)). For N\geq 3 we find a cubic fixed point in the region $u, v \geq 0$, which is marginally stable or unstable according to the sign of the perturbation. For the physical relevant case of N=3 we find the exponents $\eta=0.17(8)$ and $\nu=1.3(3)$ at the cubic transition.Comment: 14 pages, 9 figure

Survival and adaptation of populus nigra to drier conditions after damming of an alpine river, southeast France

International audienc

Stérilisation UHT du lait : Comparaison entre un échangeur de chaleur à plaques et un chauffage ohmique

National audienc

Ohmic heating to achieve uht sterilisation of milk. Comparison with plate heat exchanger and definition of a heat dissipation coefficient

International audienc

Reducing salt level in food: Part 1. Factors affecting the manufacture of model cheese systems and their structure-texture relationships.

A model lipoproteic matrix able to mimic hard-type cheese was produced with controlled structural and textural properties. Changes in the microstructural and rheological properties of these model cheeses made from different milk concentrate powder, anhydrous milk fat, salt contents and pH values at renneting were characterised. Rheological properties were measured by texture profile analysis, fat globule and protein aggregate size distributions by laser light scattering. Microstructural properties of the model matrices were studied by confocal laser scanning and scanning electron microscopy.Significant differences between the matrices were found for the structural, physico-chemical and rheological parameters measured. Cheeses with higher dry matter content were significantly harder and contained more insoluble proteins than cheeses with lower dry matter content. The salt concentration and the pH at renneting had significant influence on cheese hardness and adhesiveness of rheological parameters. The model lipoproteic matrix presented air bubbles and powder aggregates which could not be avoided during the manufacture of products. However, compared with classic cheese making with rennet or acid coagulation, the technology used here allows model cheeses to be produced rapidly with a good reproducibility of texture

CARACTÉRISATION DE COUCHES MINCES DE VERRES DE CHALCOGENURE PRÉPARÉES PAR PECVD

Des couches minces de verres de chalcogénure, de compositions GeSe3 et GeSe5,5, déposées par PECVD sont caractérisées par différentes techniques de microscopie électronique. La structure hétérogène mise en évidence sur le matériau de composition GeSe5,5 paraît également exister pour la composition GeSe3. L'apport de la technique de dépôt par PECVD pour préparer des couches minces en vue d'applications microlithographiques est discuté.Thin films of chalcogenide glasses, with GeSe3 and GeSe5.5 compositions, were prepared by PECVD. They were characterized by various techniques of electronic microscopy. The heterogeneous structure, which appears at the GeSe5.5 composition, seems also to exist for the GeSe3 composition. The influence of the PECVD method on the microlithographic applications of this films is discussed

A cytometric study of the red blood cells in gaucher disease reveals their abnormal shape that may be involved in increased erythrophagocytosis.

International audienc

SDHA Immunohistochemistry Detects Germline SDHA Gene Mutations in Apparently Sporadic Paragangliomas and Pheochromocytomas

Tumourgenetics and immunogenetic