The Impact of Dual Enrollment on College Degree Attainment: Do Low-SES Students Benefit?

Dual enrollment in high school is viewed by many as one mechanism for increasing college admission and completion of low-income students. However, little evidence demonstrates that these students discretely benefit from dual enrollment and whether these programs narrow attainment gaps vis-à-vis students from middle-class or affluent family backgrounds. Using the National Education Longitudinal Study (N = 8,800), this study finds significant benefits in boosting rates of college degree attainment for low-income students while holding weaker effects for peers from more affluent backgrounds. These results remain even with analyses from newer data of college freshman of 2004. This report conducts sensitivity analyses and found that these results are robust to relatively large unobserved confounders. However, expanding dual enrollment programs would modestly reduce gaps in degree attainment

Estão os Alunos de Matrícula Dupla Preparados para Entrar na Faculdade? Evidências do Estudo Nacional de Artes de Wabash

We examine whether dual enrolled students display greater levels of college readiness than nonparticipants. Advocates assert that dual enrollment improves students’ college readiness, but despite these assertions, few researchers have evaluated this relationship. Moreover, researchers that do consider whether dual enrollment improves college readiness examine this relationship while students participate in dual enrollment or shortly thereafter. Unlike traditional measures of college readiness that tend to emphasize the cognitive domain of college readiness, we use measures that integrate both cognitive and noncognitive domains of college readiness. We find that students who participated in dual enrollment tend to be more college ready than those who did not earn college credit in high school. The exception is that there is no statistical difference between dual enrollees and non-accelerators in their key transition knowledge and skills. The magnitude of the dual enrollment effect is second only to gender. Examinamos si los estudiantes de matriculas duales muestran mayores niveles de preparación para la universidad que los que no participan en ese programa. Los defensores afirman que la doble inscripción mejora la preparación para la universidad de los estudiantes, pero a pesar de estas afirmaciones, pocos investigadores han evaluado esta relación. Por otra parte, los investigadores que si consideran que la doble matrícula mejora la preparación universitaria examinan esta relación mientras los estudiantes participan en doble inscripción o poco después. A diferencia de las medidas tradicionales de preparación para la universidad que tienden a enfatizar el dominio cognitivo de preparación para la universidad, utilizamos medidas que integran dominios cognitivos y no-cognitivos de preparación para la universidad. Encontramos que los estudiantes que participaron en la doble matrícula tienden a ser más preparados para la universidad que los que no ganan créditos universitarios en la escuela secundaria. La excepción es que no hay diferencia estadística entre los inscritos en matriculas duales y los que no en conocimientos y habilidades importantes para  los estudios universitarios. El efecto de magnitud de las matriculas duales sólo es superado por el género.Examinamos se os alunos de inscrição duplas mostram níveis mais elevados de preparação para a faculdade do que aqueles que não participam nesse programa. Os defensores argumentam que a dupla inscrição melhor preparação para os estudantes universitários, mas apesar destas afirmações, poucos pesquisadores avaliaram essa relação. Além disso, os pesquisadores acreditam que, se a dupla prontidão faculdade de inscrição melhora a examinar esta relação, enquanto os alunos participam de matrícula dupla ou pouco depois. Ao contrário de medidas tradicionais de prontidão para faculdade que tendem a enfatizar o domínio cognitivo de preparação para a faculdade, usamos medidas que integram domínios cognitivos e não-cognitivas na preparação para a faculdade. Descobrimos que os alunos que participaram do programa da matrícula dupla tendem a estar mais preparados para a faculdade do que aqueles que não ganham créditos universitários na escola. A exceção é que não há diferença estatística entre os alunos de dupla inscrição e os que não em conhecimentos e habilidades importantes para a faculdade. A magnitude do efeito da dupla inscrição só é superado por gênero

Social-class parenting practices and their influence on educational outcomes in the United States and Scotland

Drawing upon Lareau's (2011) work on social class and family life, this study explored social-class differences in children's cognitive outcomes from the United States and Scotland—two nations that share a policy emphasis on parental engagement to reduce the achievement gap. At the same time, the two countries differ in the extent to which such policy orientations are enforced, in the overall levels of socioeconomic inequality, and in the form and extent of welfare support for families and children. We find that parental endeavors are not unequivocally associated with children's outcomes. Findings from our decomposition analyses indicate that some practices of concerted cultivation are positively associated with children's outcomes but that the strength and direction of the relation often depend on children's social background. Moreover, social-class differences in parenting practices are more pronounced and more often statistically significant in the United States than in Scotland

A Holistic Approach to Estimating the Influence of Good Practices on Student Outcomes at Liberal Arts and non-Liberal Arts Institutions

Many higher education administrators and researchers have considered certain “good practices” of institutions as an instrumental way to improve student outcomes. Chickering and Gamson’s (1987) seven principles of good practice has been particularly salient in defining these practices. Often, prior studies only select some of the seven principles for their analysis. Even studies that consider several principles of good practice on student outcomes typically examine the net effect of each principle instead of assessing how these principles holistically influence student out-comes. Using structural equation modeling, we test a basic conceptual framework where we in-vestigate the contribution of the seven principles on a global measure of good practices (GP), as well as the influence of GP on a multitude of student outcomes. We further test whether liberal arts colleges promote an institutional ethos of good practices as compared to non-liberal arts col-leges. Overall, the majority (but not all) of the principles affect GP. Moreover, we find partial evidence that liberal arts colleges foster an institutional ethos of good practices. Although a commitment to foster good practices may create a supportive environment that influences student outcomes, this commitment may lead to unintended consequences for those with little exposure to these good practices

Regional astrocyte IFN signaling restricts pathogenesis during neurotropic viral infection

Type I IFNs promote cellular responses to viruses, and IFN receptor (IFNAR) signaling regulates the responses of endothelial cells of the blood-brain barrier (BBB) during neurotropic viral infection. However, the role of astrocytes in innate immune responses of the BBB during viral infection of the CNS remains to be fully elucidated. Here, we have demonstrated that type I IFNAR signaling in astrocytes regulates BBB permeability and protects the cerebellum from infection and immunopathology. Mice with astrocyte-specific loss of IFNAR signaling showed decreased survival after West Nile virus infection. Accelerated mortality was not due to expanded viral tropism or increased replication. Rather, viral entry increased specifically in the hindbrain of IFNAR-deficient mice, suggesting that IFNAR signaling critically regulates BBB permeability in this brain region. Pattern recognition receptors and IFN-stimulated genes had higher basal and IFN-induced expression in human and mouse cerebellar astrocytes than did cerebral cortical astrocytes, suggesting that IFNAR signaling has brain region–specific roles in CNS immune responses. Taken together, our data identify cerebellar astrocytes as key responders to viral infection and highlight the existence of distinct innate immune programs in astrocytes from evolutionarily disparate regions of the CNS

The SEGUE Stellar Parameter Pipeline. IV. Validation with an Extended Sample of Galactic Globular and Open Clusters

Spectroscopic and photometric data for likely member stars of five Galactic globular clusters (M3, M53, M71, M92, and NGC 5053) and three open clusters (M35, NGC 2158, and NGC 6791) are processed by the current version of the SEGUE Stellar Parameter Pipeline (SSPP), in order to determine estimates of metallicities and radial velocities for the clusters. These results are then compared to values from the literature. We find that the mean metallicity () and mean radial velocity () estimates for each cluster are almost all within 2{\sigma} of the adopted literature values; most are within 1{\sigma}. We also demonstrate that the new version of the SSPP achieves small, but noteworthy, improvements in estimates at the extrema of the cluster metallicity range, as compared to a previous version of the pipeline software. These results provide additional confidence in the application of the SSPP for studies of the abundances and kinematics of stellar populations in the Galaxy.Comment: 98 pages, 31 figures; accepted for publication in A

High-Energy X-ray Imaging of the Pulsar Wind Nebula MSH~15-52: Constraints on Particle Acceleration and Transport

We present the first images of the pulsar wind nebula (PWN) MSH 15-52 in the hard X-ray band (>8 keV), as measured with the Nuclear Spectroscopic Telescope Array (NuSTAR). Overall, the morphology of the PWN as measured by NuSTAR in the 3-7 keV band is similar to that seen in Chandra high-resolution imaging. However, the spatial extent decreases with energy, which we attribute to synchrotron energy losses as the particles move away from the shock. The hard-band maps show a relative deficit of counts in the northern region towards the RCW 89 thermal remnant, with significant asymmetry. We find that the integrated PWN spectra measured with NuSTAR and Chandra suggest that there is a spectral break at 6 keV which may be explained by a break in the synchrotron-emitting electron distribution at ~200 TeV and/or imperfect cross calibration. We also measure spatially resolved spectra, showing that the spectrum of the PWN softens away from the central pulsar B1509-58, and that there exists a roughly sinusoidal variation of spectral hardness in the azimuthal direction. We discuss the results using particle flow models. We find non-monotonic structure in the variation with distance of spectral hardness within 50" of the pulsar moving in the jet direction, which may imply particle and magnetic-field compression by magnetic hoop stress as previously suggested for this source. We also present 2-D maps of spectral parameters and find an interesting shell-like structure in the NH map. We discuss possible origins of the shell-like structure and their implications.Comment: 15 pages, 9 figures, accepted for publication in Ap

The Hard X-Ray View of the Young Supernova Remnant G1.9+0.3

NuSTAR observed G1.9+0.3, the youngest known supernova remnant in the Milky Way, for 350 ks and detected emission up to $\sim$30 keV. The remnant's X-ray morphology does not change significantly across the energy range from 3 to 20 keV. A combined fit between NuSTAR and CHANDRA shows that the spectrum steepens with energy. The spectral shape can be well fitted with synchrotron emission from a power-law electron energy distribution with an exponential cutoff with no additional features. It can also be described by a purely phenomenological model such as a broken power-law or a power-law with an exponential cutoff, though these descriptions lack physical motivation. Using a fixed radio flux at 1 GHz of 1.17 Jy for the synchrotron model, we get a column density of N$_{\rm H}$ = $(7.23\pm0.07) \times 10^{22}$ cm$^{-2}$, a spectral index of $\alpha=0.633\pm0.003$, and a roll-off frequency of $\nu_{\rm rolloff}=(3.07\pm0.18) \times 10^{17}$ Hz. This can be explained by particle acceleration, to a maximum energy set by the finite remnant age, in a magnetic field of about 10 $\mu$G, for which our roll-off implies a maximum energy of about 100 TeV for both electrons and ions. Much higher magnetic-field strengths would produce an electron spectrum that was cut off by radiative losses, giving a much higher roll-off frequency that is independent of magnetic-field strength. In this case, ions could be accelerated to much higher energies. A search for $^{44}$Ti emission in the 67.9 keV line results in an upper limit of $1.5 \times 10^{-5}$ $\,\mathrm{ph}\,\mathrm{cm}^{-2}\,\mathrm{s}^{-1}$ assuming a line width of 4.0 keV (1 sigma).Comment: 9 pages, 6 figures, accepted Ap

A Spatially Resolved Study of the Synchrotron Emission and Titanium in Tycho's Supernova Remnant with NuSTAR

We report results from deep observations (~750 ks) of Tycho's supernova remnant (SNR) with NuSTAR. Using these data, we produce narrow-band images over several energy bands to identify the regions producing the hardest X-rays and to search for radioactive decay line emission from 44Ti. We find that the hardest (>10 keV) X-rays are concentrated in the southwest of Tycho, where recent Chandra observations have revealed high emissivity "stripes" associated with particles accelerated to the knee of the cosmic-ray spectrum. We do not find evidence of 44Ti, and we set limits on its presence and distribution within the SNR. These limits correspond to a upper-limit 44Ti mass of M44 < 2.4x10^-4 M_sun for a distance of 2.3 kpc. We perform spatially resolved spectroscopic analysis of sixty-six regions across Tycho. We map the best-fit rolloff frequency of the hard X-ray spectra, and we compare these results to measurements of the shock expansion and ambient density. We find that the highest energy electrons are accelerated at the lowest densities and in the fastest shocks, with a steep dependence of the roll-off frequency with shock velocity. Such a dependence is predicted by models where the maximum energy of accelerated electrons is limited by the age of the SNR rather than by synchrotron losses, but this scenario requires far lower magnetic field strengths than those derived from observations in Tycho. One way to reconcile these discrepant findings is through shock obliquity effects, and future observational work is necessary to explore the role of obliquity in the particle acceleration process.Comment: 12 pages, 12 figures, ApJ in pres