New age-metallicity diagnostic diagram for the Washington photometric system

The age calibration of the Washington deltaT1 index is mainly used to estimate ages of star clusters older than 1 Gyr, no age-metallicity degeneracy effect is considered. We have profusely exploited synthetic T1 versus C-T1 colour magnitude diagrams aiming at exploring the intrinsic behaviour of the deltaT1 index. The analysis shows that deltaT1 varies with age and metal content as well. In general, the dependence on age weakens for ages greater than ~ 6 Gyr, and results even less sensitive to age as the metallicity decreases. For ages younger than ~ 5 Gyr deltaT1 shows a strong correlation with both age and metallicity. The deltaC index -defined as deltaT1 for the C passband- is also a combined measurement of age and metallicity. We introduce a new age-metallicity diagnostic diagram, deltaT1 versus deltaC - deltaT1, which has shown the ability of unambiguously providing age and metallicity estimates, simultaneously. The new procedure allows to derive ages from 1 up to 13 Gyr and metallicities [Fe/H] from -2.0 up to +0.5 dex, and is independent of the cluster reddening and distance modulus. It does solve the constraints found in the deltaT1 index and surpasses the performance of the standard giant branch metallicity method. All these features make the diagnostic diagram a powerful tool for estimating accurate ages as well as metallicities.Comment: 14 pages, 7 figures, accepted for publication in MNRA

Peaks and Troughs in Helioseismology: The Power Spectrum of Solar Oscillations

I present a matched-wave asymptotic analysis of the driving of solar oscillations by a general localised source. The analysis provides a simple mathematical description of the asymmetric peaks in the power spectrum in terms of the relative locations of eigenmodes and troughs in the spectral response. It is suggested that the difference in measured phase function between the modes and the troughs in the spectrum will provide a key diagnostic of the source of the oscillations. I also suggest a form for the asymmetric line profiles to be used in the fitting of solar power spectra. Finally I present a comparison between the numerical and asymptotic descriptions of the oscillations. The numerical results bear out the qualitative features suggested by the asymptotic analysis but suggest that numerical calculations of the locations of the troughs will be necessary for a quantitative comparison with the observations.Comment: 18 pages + 8 separate figures. To appear in Ap

Direct and alignment-insensitive measurement of cantilever curvature

We analytically derive and experimentally demonstrate a method for the simultaneous measurement of deflection for large arrays of cantilevers. The Fresnel diffraction patterns of a cantilever independently reveals tilt, curvature, cubic and higher order bending of the cantilever. It provides a calibrated absolute measurement of the polynomial coefficients describing the cantilever shape, without careful alignment and could be applied to several cantilevers simultaneously with no added complexity. We show that the method is easily implemented, works in both liquid mediums and in air, for a broad range of displacements and is especially suited to the requirements for multi-marker biosensors.Comment: 5 Pages, 4 figures, letter forma

Strong Coupling Solver for the Quantum Impurity Model

We propose a fast impurity solver for the general quantum impurity model based on the perturbation theory around the atomic limit, which can be used in combination with the local density approximation (LDA) and the dynamical mean field theory (DMFT). We benchmark the solver in the two band Hubbard model within DMFT against quantum Monte Carlo (QMC) and numerical renormalization group (NRG) results. We find that the solver works very well in the paramagnetic Mott insulator phase. We also apply this impurity solver to the DMFT study of the anti-ferromagnetic phase transition in the unfrustrated Bethe lattice. The Neel temperature obtained by the fast impurity solver agrees very well with the QMC results in the large Hubbard U limit. The method is a promising tool to be used in combination with the LDA+DMFT to study Mott insulators starting from first principles.Comment: 5 pages, 5 figures. to be published in Physical Review

Religion and Attitudes toward Same-Sex Marriage among U.S. Latinos

Objectives. This study examines links between multiple aspects of religious involvement and attitudes toward same-sex marriage among U.S. Latinos. The primary focus is on variations by affiliation and participation, but the possible mediating roles of biblical beliefs, clergy cues, and the role of religion in shaping political views are also considered. Methods. We use binary logistic regression models to analyze data from a large nationwide sample of U.S. Latinos conducted by the Pew Hispanic Forum in late 2006. Results. Findings highlight the strong opposition to same-sex marriage among Latino evangelical (or conservative) Protestants and members of sectarian groups (e.g., LDS), even compared with devout Catholics. Although each of the hypothesized mediators is significantly linked with attitudes toward same-sex marriage, for the most part controlling for them does not alter the massive affiliation/attendance differences in attitudes toward same-sex marriage. Conclusions. This study illustrates the importance of religious cleavages in public opinion on social issues within the diverse U.S. Latino population. The significance of religious variations in Hispanic civic life is likely to increase with the growth of the Latino population and the rising numbers of Protestants and sectarians among Latinos