Black holes in symmetric spaces : anti-de Sitter spaces

Using symmetric space techniques, we show that closed orbits of the Iwasawa subgroups of $SO(2,l-1)$ naturally define singularities of a black hole causal structure in anti-de Sitter spaces in $l \geq 3$ dimensions. In particular, we recover for $l=3$ the non-rotating massive BTZ black hole. The method presented here is very simple and in principle generalizable to any semi-simple symmetric space.Comment: 23 pages, no figur

Quantized anti de Sitter spaces and non-formal deformation quantizations of symplectic symmetric spaces

We realize quantized anti de Sitter space black holes, building Connes spectral triples, similar to those used for quantized spheres but based on Universal Deformation Quantization Formulas (UDF) obtained from an oscillatory integral kernel on an appropriate symplectic symmetric space. More precisely we first obtain a UDF for Lie subgroups acting on a symplectic symmetric space M in a locally simply transitive manner. Then, observing that a curvature contraction canonically relates anti de Sitter geometry to the geometry of symplectic symmetric spaces, we use that UDF to define what we call Dirac-isospectral noncommutative deformations of the spectral triples of locally anti de Sitter black holes. The study is motivated by physical and cosmological considerations.Comment: 24 pages, to appear in Contemporary Mathematics (AMS) in the volume of the proceedings of the conference Poisson 2006 held at Keio Univ (Japan

Autécologie du frêne commun (Fraxinus excelsior L.) et du frêne oxyphylle (Fraxinus angustifolia Vahl)

Fiche réalisée dans le cadre du projet européen interreg 4a « Pirinoble » (www.pirinoble.eu) associant quatre partenaires français et espagnols : CNPF - Institut pour le Développement Forestier (IDF), Centre Régional de la Propriété Forestière de Midi-Pyrénées (CRPF), Centre Tecnològic Forestal de Catalunya CTFC), Centre de la Propietat Forestal (CPF)

Sex hormone-binding globulin regulation of androgen bioactivity in vivo : validation of the free hormone hypothesis

Sex hormone-binding globulin (SHBG) is the high-affinity binding protein for androgens and estrogens. According to the free hormone hypothesis, SHBG modulates the bioactivity of sex steroids by limiting their diffusion into target tissues. Still, the in vivo physiological role of circulating SHBG remains unclear, especially since mice and rats lack circulating SHBG post-natally. To test the free hormone hypothesis in vivo, we examined total and free sex steroid concentrations and bioactivity on target organs in mice expressing a human SHBG transgene. SHBG increased total androgen and estrogen concentrations via hypothalamic-pituitary feedback regulation and prolonged ligand half-life. Despite markedly raised total sex steroid concentrations, free testosterone was unaffected while sex steroid bioactivity on male and female reproductive organs was attenuated. This occurred via a liganddependent, genotype-independent mechanism according to in vitro seminal vesicle organ cultures. These results provide compelling support for the determination of free or bioavailable sex steroid concentrations in medicine, and clarify important comparative differences between translational mouse models and human endocrinology

La station de recherches de Saint-Eugène : situation, environnement et présentation générale

This paper presents the field research station of the Muséum national d'Histoire naturelle (MNHN) at Saint-Eugène, through its history, its natural environment, and its equipping. Main habitats encountered on and around the Petit Saut reservoir are described, together with their evolution following dam flooding. A general map of the Saint-Eugène area shows all the MNHN study sites (mainland and islands). A table summarizes their characteristics of surface and isolation, as well as main topics under study as yetL'article présente la station de terrain du Muséum national d'Histoire naturelle (MNHN) à Saint-Eugène, à travers son historique, son environnement naturel et ses aménagements. Les principaux habitats rencontrés sur et en bordure de la retenue du barrage de Petit Saut, ainsi que leur évolution consécutive à la mise en eau du barrage, sont décrits. Une carte générale de Saint-Eugène présente l'ensemble des sites d'étude (îles et terre ferme) du MNHN. Un tableau résume leurs caractéristiques de surface et d'isolement, ainsi que les centres d'intérêt dont ils ont fait 1'obje

Autecology of broadleaved species

Anyone involved in timber production needs some knowledge of autecology. With the renewed interest in hardwoods in the last 20 years, they are increasingly being introduced by planting or encouraged in natural stands. The results in terms of growth have not always met foresters’ expectations, due to technical problems and especially because the species are not always suited to the different sites. While the principle of establishing hardwoods is not in question, it is important to be aware of the conditions they need for their growth. This is why the first component of the Pirinoble programme is about improving knowledge on the ecology and adaptation of valuable hardwood species. To support this, a wide-ranging bibliographic analysis was made of scientific publications in French, English, Spanish and Italian on the main hardwood species that can be established as plantations: - Wild Cherry (Prunus avium l.), - Common Ash (Fraxinus SSP.), - Wild service tree (Sorbus torminalis l.), service tree (Sorbus domestica L.) and other sorbus species. - Walnut (Juglans SSP.), - Common pear tree (Pyrus pyraster (l.) Du ROI) and the European Wild Apple tree (Malus sylvestris Mill.). - Lime (Tilia ssp.), - Maple (Acer SSP.). Favourable site conditions for hardwood trees are now better understood thanks to numerous observations carried out in stands and a number of scientific studies. Some species have been studied in more depth, including the wild cherry, wild service tree, common ash, maple and walnut. This guide is based on the results of these studies, supplemented by the expertise of the authors. It includes a series of autecology factsheets that describe the site conditions in which hardwoods will thrive and the minimum conditions required for rapid timber production. The factsheets were published on a regular basis in Forêt-entreprise in 2012 and 2013 (see footnote at the end of each of factsheet), and are now published together in this guide along with the bibliographical references consulted

Early effects of androgen deprivation on bone and mineral homeostasis in adult men: a prospective cohort study

Objective: Long-term androgen deprivation therapy (ADT) negatively influences bone. The short term effects on bone and mineral homeostasis are less known. Therefore, we aimed to investigate the early effects of ADT on calcium/phosphate homeostasis and bone turnover. Design: Prospective cohort study Methods: Eugonadal adult male sex offenders, who were referred for ADT to the endocrine outpatient clinic, received cyproterone acetate. Changes in blood markers of calcium/phosphate homeostasis and bone turnover between baseline and first follow-up visit were studied. Results: Of 26 screened patients, 17 were included. The median age was 44 (range 20-75) years. The median time interval between baseline and first follow-up was 13 (6-27) weeks. Compared to baseline, an 81% decrease was observed for median total testosterone (to 3.4 nmol/L (0.4-12.2); P<0.0001) and free testosterone (to 0.06 nmol/L (0.01-0.18); P<0.0001). Median total estradiol decreased 71% (to 17.6 pmol/L (4.7-35.6); P<0.0001). Increased serum calcium (P<0.0001) and phosphate (P=0.0016) was observed, paralleled by decreased PTH (P=0.0156) and 1,25 dihydroxyvitamin D3 (P=0.0134). The stable calcium isotope ratio (δ44/42Ca) decreased (P=0.0458), indicating net calcium loss from bone. Bone-specific alkaline phosphatase and osteocalcin decreased (P<0.0001 and P=0.0056, respectively), periostin tended to decrease (P=0.0500) whereas sclerostin increased (P<0.0001), indicating suppressed bone formation. Serum bone resorption markers (TRAcP5b, CTX) were unaltered. Conclusions: In adult men, calcium release from the skeleton occurs early following sex steroid deprivation, reflecting early bone resorption. The increase of sclerostin and reduction of bone formation markers, without changes in resorption markers, suggests a dominant negative effect on bone formation in the acute phase