An integrated model of academic self-concept development: academic self-concept, grades, test scores, and tracking over six years

Our newly proposed Integrated Academic Self-concept Model integrates three major theories of academic self-concept formation and developmental perspectives into a unified conceptual and methodological framework. Relations among math self-concept (MSC), school grades, test scores, and school-level contextual effects over six years, from the end of primary school through the first five years of secondary school (a representative sample of 3,370 German students, 42 secondary schools, 50% males, Mn age = 11.75) support the: 1. Internal/external frame of reference model: math school grades had positive effects on MSC, but the effects of German grades were negative; 2. Reciprocal effects (longitudinal panel) model: MSC was predictive of and predicted by math test scores and school grades; 3. Big-fish-little-pond effect: the effects on MSC were negative for school-average achievement based on four indicators (primary school grades in math and German; school-track prior to the start of secondary school; math test scores in the first year of secondary school). Results in all three theoretical models were consistent across the five secondary school years: this supports the prediction of developmental equilibrium. This integration highlights the robustness of support over the potentially volatile early-to-middle adolescent period, the interconnectedness and complementarity of three ASC models, their counter-balancing strengths and weaknesses, and new theoretical, developmental, and substantive implications at their intersections

The mass of the neutron star in Cyg X-2 (V1341 Cyg)

Cygnus X-2 is one of the brightest and longest known X-ray sources. We present high resolution optical spectroscopy of Cyg X-2 obtained over 4 years which gives an improved mass function of 0.69 +/- 0.03 Msun (1 sigma error). In addition, we resolve the rotationally broadened absorption features of the secondary star for the first time, deriving a rotation speed of vsin(i) = 34.2 +/- 2.5 km per s (1 sigma error) which leads to a mass ratio of q = M_c/M_x = 0.34 +/- 0.04 (1 sigma error), assuming a tidally-locked and Roche lobe-filling secondary). Hence with the lack of X-ray eclipses (i.e. i <~ 73 degrees) we can set firm 95% confidence lower limits to the neutron star mass of M_x > 1.27 Msun and to the companion star mass of M_c > 0.39 Msun. However, by additionally requiring that the companion must exceed 0.75 Msun (as required theoretically to produce a steady low-mass X-ray binary), then M_x > 1.88 Msun and i < 61 degrees (95% confidence lower and upper limit, respectively), thereby making Cyg X-2 the highest mass neutron star measured to date. If confirmed this would set significant constraints on the equation of state of nuclear matter.Comment: 16 pages, 4 figures, ApJ Letters, accepted, LaTeX, aasms4.st

Polls and the political process: the use of opinion polls by political parties and mass media organizations in European post‐communist societies (1990–95)

Opinion polling occupies a significant role within the political process of most liberal-capitalist societies, where it is used by governments, parties and the mass media alike. This paper examines the extent to which polls are used for the same purposes in the post-communist countries of Central and Eastern Europe, and in particular, for bringing political elites and citizens together. It argues that these political elites are more concerned with using opinion polls for gaining competitive advantage over their rivals and for reaffirming their political power, than for devolving political power to citizens and improving the general processes of democratization

A Study of the Diverse T Dwarf Population Revealed by WISE

We report the discovery of 87 new T dwarfs uncovered with the Wide-field Infrared Survey Explorer (WISE) and three brown dwarfs with extremely red near-infrared colors that exhibit characteristics of both L and T dwarfs. Two of the new T dwarfs are likely binaries with L7+/-1 primaries and mid-type T secondaries. In addition, our follow-up program has confirmed 10 previously identified T dwarfs and four photometrically-selected L and T dwarf candidates in the literature. This sample, along with the previous WISE discoveries, triples the number of known brown dwarfs with spectral types later than T5. Using the WISE All-Sky Source Catalog we present updated color-color and color-type diagrams for all the WISE-discovered T and Y dwarfs. Near-infrared spectra of the new discoveries are presented, along with spectral classifications. To accommodate later T dwarfs we have modified the integrated flux method of determining spectral indices to instead use the median flux. Furthermore, a newly defined J-narrow index differentiates the early-type Y dwarfs from late-type T dwarfs based on the J-band continuum slope. The K/J indices for this expanded sample show that 32% of late-type T dwarfs have suppressed K-band flux and are blue relative to the spectral standards, while only 11% are redder than the standards. Comparison of the Y/J and K/J index to models suggests diverse atmospheric conditions and supports the possible re-emergence of clouds after the L/T transition. We also discuss peculiar brown dwarfs and candidates that were found not to be substellar, including two Young Stellar Objects and two Active Galactic Nuclei. The coolest WISE-discovered brown dwarfs are the closest of their type and will remain the only sample of their kind for many years to come.Comment: Accepted to ApJS on 15 January 2013; 99 pages in preprint format, 30 figures, 12 table

Bostonia: The Boston University Alumni Magazine. Volume 12

Founded in 1900, Bostonia magazine is Boston University’s main alumni publication

A multination study of socioeconomic inequality in expectations for progression to higher education: the role of between-school tracking and ability stratification

Persistent inequalities in educational expectations across societies are a growing concern. Recent research has explored the extent to which inequalities in education are due to primary effects (i.e., achievement differentials) versus secondary effects (i.e., choice behaviors net of achievement). We explore educational expectations in order to consider whether variations in primary and secondary effects are associated with country variation in curricular and ability stratification. We use evidence from the PISA 2003 database to test the hypothesis that (a) greater between-school academic stratification would be associated with stronger relationships between socioeconomic status and educational expectations and (b) when this effect is decomposed, achievement differentials would explain a greater proportion of this relationship in countries with greater stratification. Results supported these hypotheses

Physical self-concept changes in a selective sport high school : A longitudinal cohort-sequence analysis of the big-fish-little-pond effect

Elite athletes and nonathletes (N = 1,268) attending the same selective sport high school (4 high school age cohorts, grades 7-10, mean ages varying from 10.9 to 14.1) completed the same physical self-concept instrument 4 times over a 2-year period (multiple waves). We introduce a latent cohort-sequence analysis that provides a stronger basis for assessing developmental stability/change than either cross-sectional (multicohort, single occasion) or longitudinal (single-cohort, multiple occasion) designs, allowing us to evaluate latent means across 10 waves spanning a 5-year period (grades 7-11), although each participant contributed data for only 4 waves, spanning 2 of the 5 years. Consistent with the frame-of-reference effects embodied in the big-fish-little-pond effect (BFLPE), physical self-concepts at the start of high school were much higher for elite athletes than for nonathlete classmates, but the differences declined over time so that by the end of high school there were no differences in the 2 groups. Gender differences in favor of males had a negative linear and quadratic trajectory over time, but the consistently smaller gender differences for athletes than for nonathletes did not vary with time

Cross-cultural generalizability of social and dimensional comparison effects on reading, math, and science self-concepts for primary school students using the combined PIRLS and TIMSS data

Previous cross-cultural studies of social and dimensional comparison processes forming academic self-concepts (the big-fish-little-pond effect (BFLPE) and Internal-external frame-of-reference (I/E) models) have mostly been based on high-school students and two subject domains. Our study is the first to test the cross-cultural generalizability of both comparison processes across reading, mathematics, and science by combining of the TIMSS and PIRLS 2011 databases (15 OECD countries, 67,386 fourth-graders). Consistent with the I/E model, high achievement in mathematics/reading had positive effects on self-concept in the matching domain but negative effects in the non-matching domain. Extending the I/E model, students engaged in assimilating comparisons between science and reading (i.e., achievement in one subject had positive effects on self-concept in the other) but contrasting comparisons between mathematics and science. Strong BFLPEs (negative effects of class-average achievement on self-concept) were found for mathematics but were smaller for reading and science. The results generalized well across all countries

Bioassay studies support the potential for latrogenic transmission of variant Creutzfeldt Jakob disease through dental procedures

Background: Evidence is required to quantify the potential risks of transmission of variant Creutzfeldt Jakob (vCJD) through dental procedures. Studies, using animal models relevant to vCJD, were performed to address two questions. Firstly, whether oral tissues could become infectious following dietary exposure to BSE? Secondly, would a vCJD-contaminated dental instrument be able to transmit disease to another patient? Methods: BSE-301V was used as a clinically relevant model for vCJD. VM-mice were challenged by injection of infected brain homogenate into the small intestine (Q1) or by five minute contact between a deliberately-contaminated dental file and the gingival margin (Q2). Ten tissues were collected from groups of challenged mice at three or four weekly intervals, respectively. Each tissue was pooled, homogenised and bioassayed in indicator mice. Findings: Challenge via the small intestine gave a transmission rate of 100% (mean incubation 157±17 days). Infectivity was found in both dental pulp and the gingival margin within 3 weeks of challenge and was observed in all tissues tested within the oral cavity before the appearance of clinical symptoms. Following exposure to deliberately contaminated dental files, 97% of mice developed clinical disease (mean incubation 234±33 days). Interpretation: Infectivity was higher than expected, in a wider range of oral tissues, than was allowed for in previous risk assessments. Disease was transmitted following transient exposure of the gingiva to a contaminated dental file. These observations provide evidence that dental procedures could be a route of cross-infection for vCJD and support the enforcement of single-use for certain dental instruments

Achievement, motivation, and educational choices : A longitudinal study of expectancy and value using a multiplicative perspective

Drawing on the expectancy-value model, the present study explored individual and gender differences in university entry and selection of educational pathway (e.g., science, technology, engineering, and mathematics [STEM] course selection). In particular, we examined the multiplicative effects of expectancy and task values on educational outcomes during the transition into early adulthood. Participants were from a nationally representative longitudinal sample of 15-year-old Australian youths (N = 10,370). The results suggest that (a) both math self-concept and intrinsic value interact in predicting advanced math course selection, matriculation results, entrance into university, and STEM fields of study; (b) prior reading achievement has negative effects on advanced math course selection and STEM fields through math motivational beliefs; and (c) gender differences in educational outcomes are mediated by gender differences in motivational beliefs and prior academic achievement, while the processes underlying choice of educational pathway were similar for males and females