A closure theory for the split energy-helicity cascades in homogeneous isotropic homochiral turbulence

We study the energy transfer properties of three dimensional homogeneous and isotropic turbulence where the non-linear transfer is altered in a way that helicity is made sign-definite, say positive. In this framework, known as homochiral turbulence, an adapted eddy-damped quasi-normal Markovian (EDQNM) closure is derived to analyze the dynamics at very large Reynolds numbers, of order $10^5$ based on the Taylor scale. In agreement with previous findings, an inverse cascade of energy with a kinetic energy spectrum like $\propto k^{-5/3}$ is found for scales larger than the forcing one. Conjointly, a forward cascade of helicity towards larger wavenumbers is obtained, where the kinetic energy spectrum scales like $\propto k^{-7/3}$. By following the evolution of the closed spectral equations for a very long time and over a huge extensions of scales, we found the developing of a non monotonic shape for the front of the inverse energy flux. The very long time evolution of the kinetic energy and integral scale in both the forced and unforced cases is analyzed also.Comment: 8 pages, 3 figure

The Chemical Compositions Of RR Lyrae Type C Variable Stars

We present a detailed chemical abundance study of eight RR Lyrae variable stars of subclass c (RRc). The target RRc stars chosen for study exhibit "Blazhko-effect" period and amplitude modulations to their pulsational cycles. Data for this study were gathered with the echelle spectrograph of the 100 inch du Pont telescope at Las Campanas Observatory. Spectra were obtained throughout each star's pulsation cycle. Atmospheric parameters-effective temperature, surface gravity, microturbulent velocity, and metallicity-were derived at multiple phase points. We found metallicities and element abundance ratios to be constant within observational uncertainties over the pulsational cycles of all stars. Moreover, the alpha-element and Fe-group abundance ratios with respect to iron are consistent with other horizontal-branch members (RRab, blue and red non-variables). Finally, we have used the [Fe/H] values of these eight RRc stars to anchor the metallicity estimates of a large-sample RRc snapshot spectroscopic study being conducted with the same telescope and instrument combination employed here.NSF AST-0908978, AST-1211585Baker Centennial Research EndowmentJohn W. Cox Endowment for the Advanced Studies in AstronomyMcDonald Observator

Household Sector Borrowing in the Euro Area: A Micro Data Persective

This paper uses microdata from the EU-SILC (Statistics on Income and Living Conditions) to generate structural information for the euro area on the incidence of household indebtedness and of the burden to service debt. It distinguishes this incidence according to relevant characteristics such as income, age and employment status, all elements that can be cross-examined in the light of theories such as the life-cycle hypothesis. Overall, income appears as the dominant feature determining the debt status of a household. The paper also examines the evolution of indebtedness and debt service burdens over time and compares it with the US. In general, the results suggest that the macroeconomic implications of indebtedness for monetary transmission and financial stability are not associated with the mean but with the tails of the distribution.household indebtedness, financial vulnerability, micro survey data, monetary transmission.

QUALITY OF ADVANCED PLACEMENT PROGRAMS

There has been an abundance of research studies regarding the underrepresentation of minoritized students (i.e., Latino & African Americans) in high school Advanced Placement programs. However, recent or current research studies have demonstrated that although this issue has improved over the years. A new problem has emerged for minoritized high school students regarding the “quality” of Advanced Placement programs. More specifically, minoritized students in urban school districts are being allowed to be enrolled in subpar Advanced Placement programs. Moreover, research has indicated that Advanced Placement programs in urban schools are of unequal quality among minoritized students. It is not only sufficient to just offer more AP courses to low income students but rather it is more important to provide these student populations with equity in AP course quality