Some Applications of the Lee-Yang Theorem

For lattice systems of statistical mechanics satisfying a Lee-Yang property (i.e., for which the Lee-Yang circle theorem holds), we present a simple proof of analyticity of (connected) correlations as functions of an external magnetic field h, for Re h > 0 or Re h < 0. A survey of models known to have the Lee-Yang property is given. We conclude by describing various applications of the aforementioned analyticity in h.Comment: 16 page

Explicit predictability and dispersion scaling exponents in fully developed turbulence

We apply a simple method to provide explicit expressions for different scaling exponents in intermittent fully developed turbulence, that before were only given through a Legendre transform. This includes predictability exponents for infinitesimal and non infinitesimal perturbations, Lagrangian velocity exponents, and dispersion exponents. We obtain also new results concerning inverse statistics corresponding to exit-time moments.Comment: Physics Letters A (in press

ProAKAP4 Semen Concentrations as a Valuable Marker Protein of Post-Thawed Semen Quality and Bull Fertility : a Retrospective Study

Functional sperm quality markers to predict bull fertility have been actively investigated. Among them, proAKAP4, which is the precursor of AKAP4, the main structural protein in the fibrous sheath of spermatozoa; appears to be promising, especially since spermatozoa lacking AKAP4 expression were shown to be immotile, abnormal, and infertile. In this study, the objective was to evaluate proAKAP4 concentration values with the classic sperm motility descriptors and fertility outcomes (NRR at 90 days) in post-thawed conditions of 10 bulls' semen. ProAKAP4 expression was confirmed by Western blotting and proAKAP4 concentrations were determined by ELISA. Variations in proAKAP4 concentrations were observed independently of the motility sperm descriptors measured using computer-assisted semen analysis (CASA). A ProAKAP4 concentration of 38.67 ± 8.55 ng/10 million spermatozoa was obtained as a statistical mean of all samples. Threshold values of proAKAP4 were then determined between 19.96 to 96.95 ng/10 million spermatozoa. ProAKAP4 concentrations were positively correlated with progressive motility and the linearity coefficient. The sperm showing the lowest progressive motility were the samples exhibiting proAKAP4 concentrations below 20 ng/10 million spermatozoa. Furthermore, proAKAP4 concentrations were significantly higher in bulls with a higher NRR in the field. Our results demonstrate a correlation between the semen concentration of proAKAP4 and NRR-90d (p = 0.05) in post-thawed bull semen, highlighting the potential of proAKAP4 as a predictive marker of bull fertility

RNA interference and nonviral targeted gene therapy of experimental brain cancer

According to isotopic labeling experiments, most of the carbon used by truffle (Tuber sp.) fruiting bodies to develop underground is provided by host trees, suggesting that trees and truffles are physically connected. However, such physical link between trees and truffle fruiting bodies has never been observed.We discovered fruiting bodies of Tuber aestivum adhering to the walls of a belowground quarry and we took advantage of this unique situation to analyze the physical structure that supported these fruiting bodies in the open air. Observation of transversal sections of the attachment structure indicated that it was organized in ducts made of gleba-like tissue and connected to a network of hyphae traveling across soil particles.Only one mating type was detected by PCR in the gleba and in the attachment structure, suggesting that these two organs are from maternal origin, leaving open the question of the location of the opposite paternal mating type

Transmitted drug resistance, selection of resistance mutations and moderate antiretroviral efficacy in HIV-2: Analysis of the HIV-2 Belgium and Luxembourg database

BACKGROUND: Guidelines established for the treatment of HIV-1 infection and genotype interpretation do not apply for HIV-2. Data about antiretroviral (ARV) drug efficacy and resistance mutations is scarce. METHODS: Clinical data about HIV-2 infected patients in Belgium and Luxembourg were collected and the effect of ARV therapy on plasma viral load and CD4 counts were analysed. Viral RNA encoding for protease (PR) and reverse transcriptase (RT) from ARV-naive and treated patients were sequenced. RESULTS: Sixty-five HIV-2 infected patients were included in this cohort. Twenty patients were treated with 25 different ARV combinations in a total of 34 regimens and six months after the start of ARV therapy, only one third achieved viral load suppression. All of these successful regimens bar one contained protease inhibitors (PIs). Mean CD4 gains in the group of viral load suppressors and the group of patients treated with PI-containing regimens were respectively significantly higher than in the group of non-suppressors and the group of PI-sparing regimens. The most frequent mutations selected under therapy (compared to HIV-2 ROD) were V71I, L90M and I89V within PR. Within RT, they were M184V, Q151M, V111I and K65R. All of these mutations, except K65R and M184V, were also found in variable proportions in ARV-naive patients. CONCLUSION: Despite a high rate of ARV treatment failure, better virological and immunological results were achieved with PI-containing regimens. The analysis of polymorphic positions and HIV-2 specific mutations selected during therapy showed for the first time that transmission of drug resistant viruses has occurred in Belgium and Luxembourg. The high heterogeneity in ARV combinations reflects a lack of guidelines for the treatment of HIV-2 infection

A statistical approach to estimating the strength of cell-cell interactions under the differential adhesion hypothesis

International audienceBACKGROUND: The Differential Adhesion Hypothesis (DAH) is a theory of the organization of cells within a tissue which has been validated by several biological experiments and tested against several alternative computational models. RESULTS: In this study, a statistical approach was developed for the estimation of the strength of adhesion, incorporating earlier discrete lattice models into a continuous marked point process framework. This framework allows to describe an ergodic Markov Chain Monte Carlo algorithm that can simulate the model and reproduce empirical biological patterns. The estimation procedure, based on a pseudo-likelihood approximation, is validated with simulations, and a brief application to medulloblastoma stained by beta-catenin markers is given. CONCLUSION: Our model includes the strength of cell-cell adhesion as a statistical parameter. The estimation procedure for this parameter is consistent with experimental data and would be useful for high-throughput cancer studies

L'Aventure des Normands (VIIIe-XIIIe siècle)

[Collection : Pour L'histoire, ISBN : 2-262-01977-0]Les Normands sont les " hommes du Nord ", à l'origine des Vikings venus par bateau des régions scandinaves jusqu'aux rivages de l'Europe occidentale. Après avoir ravagé les régions traversées lors de raids très meurtriers, ils s'y sont finalement implantés, en y bâtissant des Etats. Ainsi est née la Normandie, indépendante jusqu'en 1204 et sûrement la principauté la mieux administrée du royaume de France en l'an mil. En 1066, le jeune duc de Normandie, Guillaume le Conquérant, lançait une audacieuse expédition pour s'emparer du royaume d'Angleterre, fondant ainsi l'Etat anglo-normand. A la même époque, d'autres Normands entreprirent la conquête de l'Italie du Sud, sous la conduite d'aventuriers intrépides comme les frères de Hauteville, et surtout Robert Guiscard. A la génération suivante, Roger II de Hauteville rassembla toutes les terres conquises par les Normands et fonda en 1130 le royaume de Sicile. A ces deux royaumes normands, il faut ajouter la principauté d'Antioche constituée par Bohémond, un fils de Robert Guiscard, à l'occasion de la première croisade. Ces Etats remarquablement bien gouvernés feront figure de modèles pour l'ensemble des royaumes d'Occident. Quelques-uns des souverains les plus prestigieux de ce temps sont issus de la génération des conquérants : les rois d'Angleterre Henri Ie Beauclerc, Henri II et Richard Cœur de lion, mais aussi l'empereur Frédéric II. Avec sa mort, en 1250, s'achève le cycle de cette extraordinaire aventure des Normands. - Sommaire - • Il était une fois les Scandinaves • Premiers raids vikings • La fondation de la Normandie • Une nouvelle principauté • Robert le Magnifique • Guillaume, le conquérant de l'Angleterre • La fabuleuse histoire des frères de Hauteville • Grandeurs et décadence