The sigma - L correlation in Nearby Early-Type Galaxies

Early-type galaxy velocity dispersions and luminosities are correlated. The correlation estimated in local samples (< 100 Mpc) differs from that measured more recently in the SDSS. This is true even when systematics in the SDSS photometric and spectroscopic parameters have been accounted-for. We show that this is also true for the ENEAR sample if galaxy luminosities are estimated using distances which have been corrected for peculiar motions. We then show that, because the estimate of the `true' distance is derived from a correlation with velocity dispersion, in this case the D_n-sigma relation, using it in the sigma-L relation leads to an artificially tight relation with a biased slope. Making no correction for peculiar velocities results in a sigma-L relation which is very similar to that of the SDSS, although with larger scatter. We also measure the sigma-L correlation in a mock ENEAR catalog, in which the underlying galaxy sample has the same sigma-L correlation as seen in the SDSS. The mock catalog produces the same D_n-sigma relation as the data, the same biased slope when D_n-sigma distances are used to estimate luminosities, and good agreement with the input sigma-L relation when redshift is used as the distance indicator. This provides further evidence that the true sigma-L relation of ENEAR galaxies is indeed very similar to that of SDSS early-types. Our results suggest that local sigma-L relations which are based on Fundamental Plane distances should also be re-evaluated. Our findings also have important implications for black hole demographics; the best direct estimates of the masses of supermassive black holes come from local galaxies, so estimates of the black hole mass function are more safely made by working with the Mbh-sigma correlation than with Mbh-L.Comment: 9 pages, 9 figures. Accepted by AJ. A new appendix describes systematics effects we found in the SDSS velocity dispersion measurements (sigmas < 150 km/s are biased towards larger values; this bias was not present in the Bernardi et al. 2003 sample) and luminosity measurement

Test of Universality in the Ising Spin Glass Using High Temperature Graph Expansion

We calculate high-temperature graph expansions for the Ising spin glass model with 4 symmetric random distribution functions for its nearest neighbor interaction constants J_{ij}. Series for the Edwards-Anderson susceptibility \chi_EA are obtained to order 13 in the expansion variable (J/(k_B T))^2 for the general d-dimensional hyper-cubic lattice, where the parameter J determines the width of the distributions. We explain in detail how the expansions are calculated. The analysis, using the Dlog-Pad\'e approximation and the techniques known as M1 and M2, leads to estimates for the critical threshold (J/(k_B T_c))^2 and for the critical exponent \gamma in dimensions 4, 5, 7 and 8 for all the distribution functions. In each dimension the values for \gamma agree, within their uncertainty margins, with a common value for the different distributions, thus confirming universality.Comment: 13 figure

Why should parental leave policies (not) be implemented? A frame analysis of French-speaking Swiss press articles: 1999-2009

This paper analyses the media coverage of parental leave policies (parental and paternity leaves) in Swiss French-speaking press articles from 1999 to 2009. Switzerland is one of the rare European countries, which has no statutory parental or paternity leave. The aim is to describe the mediatization of these policies and to analyze the arguments in favor of and against their implementation. We proceed with a content analysis of 579 press articles, as well as a frame analysis on a subset in which parental leave policies are the central theme (N=206). Results show that paternity leave is the predominant public issue addressed in the dataset. A mediatization peak was reached in 2007, following an initiative of a member of the Federal executive to implement a short paternity leave. Parental leave policies are predominantly represented in a positive light. The primary positive frame is economic, in which leaves are represented as serving the interests of companies. Involved fatherhood and gender equality are also frequently mentioned as positive frames. The main negative frame presents parental leaves policies as secondary measures that are not truly necessary. Also, financial costs, for the employers and for society at large are frequently mentioned. We discuss the predominance of the economic frame in the media coverage of parental leave policies and suggest future avenues of research on parental leave policies in Switzerland

MOCVD-Fabricated TiO2 Thin Films: Influence of Growth Conditions on Fibroblast Cells Culture

TiO2 thin films with various morphologies were grown on Ti substrates by the LP-MOCVD technique (Low Pressure Chemical Vapour Deposition from Metal-Organic precursor), with titanium tetra-iso-propoxide as a precursor. All the films were prepared in the same conditions except the deposition time. They were characterized by X-ray diffraction, scanning electron microscopy, optical 15 interferometry, water contact angle measurements. MOCVD-fabricated TiO2 thin films are known to be adapted to cell culture for implant requirements. Human gingival fibroblasts were cultured on the various TiO2 deposits. Differences in cell viability (MTT tests) and cell spreading (qualitative assessment) were observed and related to film roughness, wettability and allotropic composition

Critical exponents in Ising spin glasses

We determine accurate values of ordering temperatures and critical exponents for Ising Spin Glass transitions in dimension 4, using a combination of finite size scaling and non-equilibrium scaling techniques. We find that the exponents $\eta$ and $z$ vary with the form of the interaction distribution, indicating non-universality at Ising spin glass transitions. These results confirm conclusions drawn from numerical data for dimension 3.Comment: 6 pages, RevTeX (or Latex, etc), 10 figures, Submitted to PR

Does environment affect the star formation histories of early-type galaxies?

Differences in the stellar populations of galaxies can be used to quantify the effect of environment on the star formation history. We target a sample of early-type galaxies from the Sloan Digital Sky Survey in two different environmental regimes: close pairs and a general sample where environment is measured by the mass of their host dark matter halo. We apply a blind source separation technique based on principal component analysis, from which we define two parameters that correlate, respectively, with the average stellar age (eta) and with the presence of recent star formation (zeta) from the spectral energy distribution of the galaxy. We find that environment leaves a second order imprint on the spectra, whereas local properties - such as internal velocity dispersion - obey a much stronger correlation with the stellar age distribution.Comment: 5 pages, 2 figures. Proceedings of JENAM 2010, Symposium 2: "Environment and the formation of galaxies: 30 years later

Efficient Ab Initio Calculations of Electron-Defect Scattering and Defect-Limited Carrier Mobility

Electron-defect ($e$-d) interactions govern charge carrier dynamics at low temperature, where they limit the carrier mobility and give rise to phenomena of broad relevance in condensed matter physics. Ab initio calculations of $e$-d interactions are still in their infancy, mainly because they require large supercells and computationally expensive workflows. Here we develop an efficient ab initio approach for computing elastic $e$-d interactions, their associated $e$-d relaxation times (RTs), and the low-temperature defect-limited carrier mobility. The method is applied to silicon with simple neutral defects, such as vacancies and interstitials. Contrary to conventional wisdom, the computed $e$-d RTs depend strongly on carrier energy and defect type, and the defect-limited mobility is temperature dependent. These results highlight the shortcomings of widely employed heuristic models of $e$-d interactions in materials. Our method opens new avenues for studying $e$-d scattering and low-temperature charge transport from first principles.Comment: 11 pages, 5 figures, submitte