Uncertainties in the solar photospheric oxygen abundance

The purpose of this work is to better understand the confidence limits of the photospheric solar oxygen abundance derived from three-dimensional models using the forbidden [OI] line at 6300 \AA , including correlations with other parameters involved. We worked with a three-dimensional empirical model and two solar intensity atlases. We employed Bayesian inference as a tool to determine the most probable value for the solar oxygen abundance given the model chosen. We considered a number of error sources, such as uncertainties in the continuum derivation, in the wavelength calibration and in the abundance/strength of Ni. Our results shows correlations between the effects of several parameters employed in the derivation. The Bayesian analysis provides robust confidence limits taking into account all of these factors in a rigorous manner. We obtain that, given the empirical three-dimensional model and the atlas observations employed here, the most probable value for the solar oxygen abundance is $\log(\epsilon_O) = 8.86\pm0.04$. However, we note that this uncertainty does not consider possible sources of systematic errors due to the model choice.Comment: Accepted for publication in Astronomy and Astrophysic

Edge magnetoplasmons in a wide armchair graphene ribbon with a weak superlattice potential: finite frequency gaps and zero group velocity

We show strong effects of a weak and smooth, on the magnetic length, superlattice potential upon edge magnetoplasmons (EMPs) at the armchair edge, with a smooth steplike electrostatic lateral confining potential, of a wide graphene channel in the $\nu=2$ quantum Hall effect regime. The superlattice potential leads to essential enlargement of a number of EMPs, descend from two fundamental EMPs in the absence of superlattice. For the wave vector $k_{x}$ within the first Brillouin zone, the EMPs show as the regions of acoustical or quasi-acoustical dispersion, with a finite value of group velocity, so the regions with frequency gaps, where a group velocity is nullified at some $k_{x}$. We obtain that for $k_{x} \to 0$ only for two EMPs the frequency tends to zero as for other EMPs it obtains finite values. Strong dependence of dispersion relations of the EMPs from the period of the superlattice $a_{0}$ and the distance $d$ from a metallic gate is shown; in particular, for typical size of a gap, for characteristic value of the frequency and $k_{x}$ at which the group velocity is reduced to zero. At the frequency that corresponds to zero group velocity of pertinent fundamental EMP branch the response of the system should present a strong resonance.Comment: 11 pages, 10 figure

Attitudes toward Marriage, Divorce, Cohabitation, and Casual Sex among Working-Age Latinos: Does Religion Matter?

The rapid growth of the Latino population in the United States has renewed interest in Latino family research. It has often been assumed that Catholicism is a key factor influencing Latinos’ attitudes toward the family, despite the fact that nearly one third of Latinos are not Catholic. This article uses data from the 2006 National Survey of Religion and Family Life, a survey of working-age adults (aged 18-59 years) in the lower 48 states, to explore the relationship between multiple dimensions of religiosity—denomination, church attendance, prayer, and beliefs about the Bible—and Latinos’ attitudes regarding marriage, divorce, cohabitation, and casual sex. Compared with Catholics, evangelical Protestants tend to hold more conservative attitudes on family-related issues. Latinos who attend services regularly and pray frequently also report more traditional views. Findings involving literalist views of the Bible are more equivocal. Taken together, religious variables are just as potent as socioeconomic and demographic factors in explaining individual-level variation in Latinos’ attitudes. Study limitations are noted, and several directions for future research are identified