High resolution UVES/VLT spectra of white dwarfs observed for the ESO SN Ia Progenitor Survey III. DA white dwarfs

Original article can be found at: http://www.aanda.org/ Copyright The European Southern Observatory (ESO) DOI: 10.1051/0004-6361/200912531Context. The ESO Supernova Ia Progenitor Survey (SPY) took high-resolution spectra of more than 1000 white dwarfs and pre-white dwarfs. About two thirds of the stars observed are hydrogen-dominated DA white dwarfs. Here we present a catalog and detailed spectroscopic analysis of the DA stars in the SPY. Aims. Atmospheric parameters effective temperature and surface gravity are determined for normal DAs. Double-degenerate binaries, DAs with magnetic fields or dM companions, are classified and discussed. Methods. The spectra are compared with theoretical model atmospheres using a fitting technique. Results. Our final sample contains 615 DAs, which show only hydrogen features in their spectra, although some are double-degenerate binaries. 187 are new detections or classifications. We also find 10 magnetic DAs (4 new) and 46 DA+dM pairs (10 new).Peer reviewe

Impacts of palustrine wetlands on surface water quality in the Lamprey River watershed, New Hampshire

Surface water chemistry was measured monthly at ten wetlands in New Hampshire from January, 2005 through October, 2006. An additional wetland was sampled intensively and only during summer-autumn, 2005, and summer, 2006. Nitrate, ammonium, dissolved organic nitrogen, total dissolved nitrogen, nitrous oxide, and dissolved organic carbon concentrations in surface waters immediately up- and downstream of the wetlands were compared and changes in concentration were modeled. Nitrate, total nitrogen, organic nitrogen, and organic carbon concentrations differed significantly between upstream and downstream sampling stations. Ammonium and nitrous oxide did not show strong differences between upstream and downstream during much of the sampling period. However, in late summer of 2006, nitrous oxide concentrations increased by three orders of magnitude. The models indicate that inflowing solute concentrations, season of year, and dissolved oxygen concentrations significantly affect changes in some solutes. Wetlands play a critical role in maintaining surface water quality in this watershed

Cytotoxic Effect of Progesterone, Tamoxifen and Their Combination in Experimental Cell Models of Human Adrenocortical Cancer

Progesterone (Pg) and estrogen (E) receptors (PgRs and ERs) are expressed in normal and neoplastic adrenal cortex, but their role is not fully understood. In literature, Pg demonstrated cytotoxic activity on AdrenoCortical Carcinoma (ACC) cells, while tamoxifen is cytotoxic in NCI-H295R cells. Here, we demonstrated that in ACC cell models, ERs were expressed in NCI-H295R cells with a prevalence of ER-β over the ER-α.Metastasis-derived MUC-1 and ACC115m cells displayed a very weak ER-α/β signal, while PgR cells were expressed, although at low level. Accordingly, these latter were resistant to the SERM tamoxifen and scarcely sensitive to Pg, as we observed a lower potency compared to NCI-H295R cells in cytotoxicity (IC50: MUC-1 cells: 67.58 µM (95%CI: 63.22-73.04), ACC115m cells: 51.76 µM (95%CI: 46.45-57.67) and cell proliferation rate. Exposure of NCI-H295R cells to tamoxifen induced cytotoxicity (IC50: 5.43 µM (95%CI: 5.18-5.69 µM) mainly involving ER-β, as their nuclear localization increased after tamoxifen: Δ A.U. treated vs untreated: 12 h: +27.04% (p < 0.01); 24 h: +36.46% (p < 0.0001). This effect involved the SF-1 protein reduction: Pg: -36.34 ± 9.26%; tamoxifen: -46.25 ± 15.68% (p < 0.01). Finally, in a cohort of 36 ACC samples, immunohistochemistry showed undetectable/low level of ERs, while PgR demonstrated a higher expression. In conclusion, ACC experimental cell models expressed PgR and low levels of ER in line with data obtained in patient tissues, thus limiting the possibility of a clinical approach targeting ER. Interestingly, Pg exerted cytotoxicity also in metastatic ACC cells, although with low potency. Keywords: ACC cell lines; ACC primary cells; adrenocortical carcinoma; estrogen receptors; progesterone receptors; tamoxifen

Spatial Mixing and Non-local Markov chains

We consider spin systems with nearest-neighbor interactions on an $n$-vertex $d$-dimensional cube of the integer lattice graph $\mathbb{Z}^d$. We study the effects that exponential decay with distance of spin correlations, specifically the strong spatial mixing condition (SSM), has on the rate of convergence to equilibrium distribution of non-local Markov chains. We prove that SSM implies $O(\log n)$ mixing of a block dynamics whose steps can be implemented efficiently. We then develop a methodology, consisting of several new comparison inequalities concerning various block dynamics, that allow us to extend this result to other non-local dynamics. As a first application of our method we prove that, if SSM holds, then the relaxation time (i.e., the inverse spectral gap) of general block dynamics is $O(r)$, where $r$ is the number of blocks. A second application of our technology concerns the Swendsen-Wang dynamics for the ferromagnetic Ising and Potts models. We show that SSM implies an $O(1)$ bound for the relaxation time. As a by-product of this implication we observe that the relaxation time of the Swendsen-Wang dynamics in square boxes of $\mathbb{Z}^2$ is $O(1)$ throughout the subcritical regime of the $q$-state Potts model, for all $q \ge 2$. We also prove that for monotone spin systems SSM implies that the mixing time of systematic scan dynamics is $O(\log n (\log \log n)^2)$. Systematic scan dynamics are widely employed in practice but have proved hard to analyze. Our proofs use a variety of techniques for the analysis of Markov chains including coupling, functional analysis and linear algebra