CD -24_17504 revisited: a new comprehensive element abundance analysis

With [Fe/H] ~ -3.3, CD -24_17504 is a canonical metal-poor main sequence turn-off star. Though it has appeared in numerous literature studies, the most comprehensive abundance analysis for the star based on high resolution, high signal-to-noise spectra is nearly 15 years old. We present a new detailed abundance analysis for 21 elements based on combined archival Keck-HIRES and VLT-UVES spectra of the star that is higher in both spectral resolution and signal-to-noise than previous data. Our results for many elements are very similar to those of an earlier comprehensive study of the star, but we present for the first time a carbon abundance from the CH G-band feature as well as improved upper limits for neutron-capture species such as Y, Ba and Eu. In particular, we find that CD -24_17504 has [Fe/H] = -3.41, [C/Fe] = +1.10, [Sr/H] = -4.68 and [Ba/H] <= -4.46, making it a carbon enhanced metal-poor star with neutron-capture element abundances among the lowest measured in Milky Way halo stars.Comment: Accepted to ApJ. 24 pages, 13 figures, 7 table

UNINTENDED CONSEQUENCES OF MASS IMPRISONMENT: EFFECTS OF PATERNAL INCARCERATION ON CHILD SCHOOL READINESS

Though sociologists have examined the consequences of mass imprisonment of African-American men on the incarcerated men, their families, and their communities, no study has considered its impact on racial disparities in educational achievement. Analyzing the Fragile Families and Child Wellbeing Study and its rich paternal incarceration data, this study asks whether children with fathers who have been in prison are less prepared for school both academically and behaviorally as a result, and whether racial disparities in imprisonment explain some of the gap in white and black children‘s educational outcomes. Using a variety of estimation strategies, I show that experiencing paternal incarceration by age 5 is associated with lower child school readiness in behavioral but not cognitive skills. While the main effect of incarceration does not vary by race, boys with incarcerated fathers in their early childhood years have substantially worse behavioral skills at school entry. Because of the negative effects of incarceration on boys‘ behavioral skills and the much higher exposure of black children to incarceration, mass incarceration facilitates the intergenerational transmission of male behavioral disadvantage, and plays a role in explaining the persistently low achievement of black boys.imprisionment, families, boys, education, race, educational achievement

Coexistence between fluid and crystalline phases of proteins in photosynthetic membranes

Photosystem II (PSII) and its associated light-harvesting complex II (LHCII) are highly concentrated in the stacked grana regions of photosynthetic thylakoid membranes. Within the membrane, PSII-LHCII supercomplexes can be arranged in disordered packings, ordered arrays, or mixtures thereof. The physical driving forces underlying array formation are unknown, complicating attempts to determine a possible functional role for arrays in regulating light harvesting or energy conversion efficiency. Here we introduce a coarse-grained model of protein interactions in coupled photosynthetic membranes, focusing on just two particle types that feature simple shapes and potential energies motivated by structural studies. Reporting on computer simulations of the model's equilibrium fluctuations, we demonstrate its success in reproducing diverse structural features observed in experiments, including extended PSII-LHCII arrays. Free energy calculations reveal that the appearance of arrays marks a phase transition from the disordered fluid state to a system-spanning crystal, which can easily be arrested by thermodynamic constraints or slow dynamics. The region of fluid-crystal coexistence is broad, encompassing much of the physiologically relevant parameter regime. Our results suggest that grana membranes lie at or near phase coexistence, conferring significant structural and functional flexibility to this densely packed membrane protein system.Comment: 11 pages, 5 figure

Data-Driven Prediction of Thresholded Time Series of Rainfall and SOC models

We study the occurrence of events, subject to threshold, in a representative SOC sandpile model and in high-resolution rainfall data. The predictability in both systems is analyzed by means of a decision variable sensitive to event clustering, and the quality of the predictions is evaluated by the receiver operating characteristics (ROC) method. In the case of the SOC sandpile model, the scaling of quiet-time distributions with increasing threshold leads to increased predictability of extreme events. A scaling theory allows us to understand all the details of the prediction procedure and to extrapolate the shape of the ROC curves for the most extreme events. For rainfall data, the quiet-time distributions do not scale for high thresholds, which means that the corresponding ROC curves cannot be straightforwardly related to those for lower thresholds.Comment: 19 pages, 10 figure

Response biases

Response biases comprise a variety of systematic tendencies of responding to questionnaire items. Response biases exert an influence on item responses in addition to any constructs that the questionnaire is designed to measure and can therefore potentially bias the corresponding trait level estimates. This chapter addresses general response biases that are independent of item content, including response styles (e.g., extreme response style, acquiescence) and rater biases (halo effect, leniency/severity bias), as well as response biases that are related to item content and depend strongly on the context (socially desirable responding). The chapter summarizes research on correlates of response biases and research on inter-individual and cross-cultural differences in engaging in response styles and rater biases. It describes different methods that can be applied at the test construction stage to prevent or minimize the occurrence of response biases. Finally, it depicts methods developed for correcting for the effects of response biases.</p

A Quantum Top Inside a Bose Josephson Junction

We consider an atomic quantum dot confined between two weakly-coupled Bose-Einstein condensates, where the dot serves as an additional tunneling channel. It is shown that the thus-embedded atomic quantum dot is a pseudospin subject to an external torque, and therefore equivalent to a quantum top. We demonstrate by numerical analysis of the time-dependent coupled evolution equations that this microscopic quantum top is very sensitive to any deviation from linear oscillatory behavior of the condensates. For sufficiently strong dot-condensate coupling, the atomic quantum dot can induce or modify the tunneling between the macroscopic condensates in the two wells.Comment: 4 pages of RevTex4, 4 figures; rewritten discussion and displayed new result