Glueballs and the Yang-Mills plasma in a TT-matrix approach

The strongly coupled phase of Yang-Mills plasma with arbitrary gauge group is studied in a $T$-matrix approach. The existence of lowest-lying glueballs, interpreted as bound states of two transverse gluons (quasi-particles in a many-body set up), is analyzed in a non-perturbative scattering formalism with the input of lattice-QCD static potentials. Glueballs are actually found to be bound up to 1.3 $T_c$. Starting from the $T$-matrix, the plasma equation of state is computed by resorting to Dashen, Ma and Bernstein's formulation of statistical mechanics and favorably compared to quenched lattice data. Special emphasis is put on SU($N$) gauge groups, for which analytical results can be obtained in the large-$N$ limit, and predictions for a $G_2$ gauge group are also given within this work.Comment: Fig. 4 corrected and references adde

The SUSY Yang-Mills plasma in a TT-matrix approach

The thermodynamic properties of ${\cal N}=1$ supersymmetric Yang-Mills theory with an arbitrary gauge group are investigated. In the confined range, we show that identifying the bound state spectrum with a Hagedorn one coming from non-critical closed superstring theory leads to a prediction for the value of the deconfining temperature $T_c$ that agrees with recent lattice data. The deconfined phase is studied by resorting to a $T$-matrix formulation of statistical mechanics in which the medium under study is seen as a gas of quasigluons and quasigluinos interacting nonperturbatively. Emphasis is put on the temperature range (1-5)~$T_c$, where the interaction are expected to be strong enough to generate bound states. Binary bound states of gluons and gluinos are indeed found to be bound up to 1.4 $T_c$ for any gauge group. The equation of state is then computed numerically for SU($N$) and $G_2$, and discussed in the case of an arbitrary gauge group. It is found to be nearly independent of the gauge group and very close to that of non-supersymmetric Yang-Mills when normalized to the Stefan-Boltzmann pressure and expressed as a function of $T/T_c$.Comment: The main conclusions of our previous versions are unchanged. This version is improved and is a fusion of our papers arXiv:1408.0958v2 and arXiv:1408.497

Interest of site-specific pollution control policies

Owing to increasing environmental concerns the current trend is to bend technical production systems in order to adapt them to the specific characteristics of the milieu and diversify them. Inherent to such dynamics is the issue of how to design the accompanying environmental policies. Theoretically, spatially targeted environmental policies are considered optimal, since economic agents tune their efforts according to the sensitivity of the milieu where they operate. But, according to empirical analyses, this advantage is undermined by the high cost of implementation, monitoring and enforcement. This paper outlines the conditions required for site-specific policies to be effective at least cost. Our starting point is the nitrate pollution of water from agriculture, which varies according to climate, soil type and agricultural production system. Farm management practices enabling to reduce pollution depend on this variability. An interdisciplinary study of the efficiency of differentiating the way this pollution is regulated was carried out on two sites in France. It focussed on assessing the importance of spatial variability in physical parameters and in private and social costs.NONPOINT POLLUTION; SITE SPECIFIC TECHNOLOGY; SITE SPECIFIC ENVIRONMENTAL POLICY; ABATEMENT COST; TRANSACTION COST

Lecture conjointe et apprentissage de la lecture

International audienc

High Dimensional Classification with combined Adaptive Sparse PLS and Logistic Regression

Motivation: The high dimensionality of genomic data calls for the development of specific classification methodologies, especially to prevent over-optimistic predictions. This challenge can be tackled by compression and variable selection, which combined constitute a powerful framework for classification, as well as data visualization and interpretation. However, current proposed combinations lead to instable and non convergent methods due to inappropriate computational frameworks. We hereby propose a stable and convergent approach for classification in high dimensional based on sparse Partial Least Squares (sparse PLS). Results: We start by proposing a new solution for the sparse PLS problem that is based on proximal operators for the case of univariate responses. Then we develop an adaptive version of the sparse PLS for classification, which combines iterative optimization of logistic regression and sparse PLS to ensure convergence and stability. Our results are confirmed on synthetic and experimental data. In particular we show how crucial convergence and stability can be when cross-validation is involved for calibration purposes. Using gene expression data we explore the prediction of breast cancer relapse. We also propose a multicategorial version of our method on the prediction of cell-types based on single-cell expression data. Availability: Our approach is implemented in the plsgenomics R-package.Comment: 9 pages, 3 figures, 4 tables + Supplementary Materials 8 pages, 3 figures, 10 table

Spatially-explicit model of sole larvae in the Southern North Sea: sensitivity of the dispersal to hydrodynamic/environment variability and biological parameters

Sole (Solea solea) is one of the most valuable commercial species in the North Sea. The size of the spawning stock is above the level of sustainable exploitation, but fishing mortality is high. The stock is therefore at risk of being harvested unsustainably. Moreover, interannual recruitment variability is very high. It is crucial to understand the contribution of hydrodynamics, environment and biological parameters to recruitment variability in order to propose appropriate measures for the management of the North Sea stock. Here we use a particle-tracking transport model coupled to a 3D hydrodynamic model to study the relative effect of hydrodynamic variability, environment variability (throughout temperature) and biological parameters on the dispersal of sole larvae in the Southern North Sea

Pairing dynamics in particle transport

We analyze the effect of pairing on particle transport in time-dependent theories based on the Hartree-Fock-Bogoliubov (HFB) or BCS approximations. The equations of motion for the HFB density matrices are unique and the theory respects the usual conservation laws defined by commutators of the conserved quantity with the Hamiltonian. In contrast, the theories based on the BCS approximation are more problematic. In the usual formulation of TDHF+BCS, the equation of continuity is violated and one sees unphysical oscillations in particle densities. This can be ameliorated by freezing the occupation numbers during the evolution in TDHF+BCS, but there are other problems with the BCS that make it doubtful for reaction dynamics. We also compare different numerical implementations of the time-dependent HFB equations. The equations of motion for the $U$ and $V$ Bogoliubov transformations are not unique, but it appears that the usual formulation is also the most efficient. Finally, we compare the time-dependent HFB solutions with numerically exact solutions of the two-particle Schrodinger equation. Depending on the treatment of the initial state, the HFB dynamics produces a particle emission rate at short times similar to that of the Schrodinger equation. At long times, the total particle emission can be quite different, due to inherent mean-field approximation of the HFB theory.Comment: 11 pages, 9 figure

Trisomy 19 ependymoma, a newly recognized genetico-histological association, including clear cell ependymoma

Ependymal tumors constitute a clinicopathologically heterogeneous group of brain tumors. They vary in regard to their age at first symptom, localization, morphology and prognosis. Genetic data also suggests heterogeneity. We define a newly recognized subset of ependymal tumors, the trisomy 19 ependymoma. Histologically, they are compact lesions characterized by a rich branched capillary network amongst which tumoral cells are regularly distributed. When containing clear cells they are called clear cell ependymoma. Most trisomy 19 ependymomas are supratentorial WHO grade III tumors of the young. Genetically, they are associated with trisomy 19, and frequently with a deletion of 13q21.31-31.2, three copies of 11q13.3-13.4, and/or deletions on chromosome 9. These altered chromosomal regions are indicative of genes and pathways involved in trisomy 19 ependymoma tumorigenesis. Recognition of this genetico-histological entity allows better understanding and dissection of ependymal tumors

Les produits de terroir : vecteurs de valorisation des aménités

Ce travail constitue une première approche des aménités et de leur valorisation potentielle via les produits alimentaires. Plus exactement, il s’agit de savoir si la valeur accordée à un produit issu d’une région bénéficiant d'un environnement naturel typé est plus importante que celle accordée à un produit issu d’une région dont l'environnement est moins attractif. Pour répondre à cette question, nous recourrons à une analyse en laboratoire qui compare deux fromages issus de deux territoires des Alpes françaises. Les résultats montrent notamment que les aménités d’un territoire, même si elles participent de la valeur affective d’un produit, ne peuvent être valorisées économiquement que s’il y a congruence entre le territoire et le produit.AMENITES;CONSENTEMENT A PAYER;EVALUATION HEDONIQUE;PRODUIT DE TERROIR; AMENITIES;WILLINGNESS TO PAY;HEDONIC VALUATION;LOCAL PRODUCT