Strategies for Systemic Change:Youth Community Organizing to Disruptthe School-to-Prison Nexus

The school disciplinary landscape across the United States changed significantly through the enactment of policies that criminalize students’ behaviors during the 1990s and 2000s. Schools began to involve the police and criminal legal system in school disciplinary issues that used to be handled by school administrators. This shift led youth of Color1 to increasingly come into contact with the juvenile legal system through school suspensions, expulsions, and referrals to alternative schools—what we characterize as the school-toprison nexus. Conceptualizing the school-to-prison pipeline as a nexus, or interlocking system of power over youth, allows us to understand how the criminalization of youth is a systemic problem that demands structural change and interventions across multiple levels of analysis and settings, including local schools, school districts, police departments, and state policies. Although important research has documented the ways that Black and Latino youth are referred to the juvenile legal system through punitive school policies, there has been less attention to the actions youth are taking to critique and dismantle these policies. Youth community organizing (YCO) against the school-to-prison nexus represents an arena of youth activism that deserves further attention and analysis. In this chapter, we define YCO as groups that create spaces for young people to think critically about their everyday social conditions, identify root causes of social problems, and build political power and voice to create policy solutions and change in their communities (Ginwright, Noguera, & Cammarota, 2006; Kirshner, 2015; Watts, Griffith, & Abdul- Adil, 1999)

Extreme ultraviolet observations of active regions in the chromosphere and the corona

Extreme ultraviolet observations of active regions in chromosphere and corona from OSO-4 spectroheliomete

A New Sub-Period-Minimum Cataclysmic Variable With Partial Hydrogen Depletion And Evidence Of Spiral Disk Structure

We present time-resolved spectroscopy and photometry of CSS 120422:111127+571239 (=SBS 1108+574), a recently discovered SU UMa-type dwarf nova whose 55 minute orbital period is well below the cataclysmic variable (CV) period minimum of similar to 78 minutes. In contrast with most other known CVs, its spectrum features He I emission of comparable strength to the Balmer lines, implying a hydrogen abundance less than 0.1 of long-period CVs-but still at least 10 times higher than that in AM CVn stars. Together, the short orbital period and remarkable helium-to-hydrogen ratio suggest that mass transfer in CSS 120422 began near the end of the donor star's main-sequence lifetime, meaning that this CV is a strong candidate progenitor of an AM CVn system as described by Podsiadlowski et al. Moreover, a Doppler tomogram of the Ha line reveals two distinct regions of enhanced emission. While one is the result of the stream-disk impact, the other is probably attributable to spiral disk structure generated when material in the outer disk achieves a 2:1 orbital resonance with respect to the donor.NSF AST-1211196, AST-9987045Department of Physics at the University of Notre DameNSF Telescope System Instrumentation Program (TSIP)Ohio Board of RegentsOhio State University Office of ResearchAstronom

A Local Hubble Bubble from SNe Ia?

We analyze the monopole in the peculiar velocities of 44 Type Ia supernovae (SNe Ia) to test for a local void. The sample extends from 20 to 300 Mpc/h, with distances, deduced from light-curve shapes, accurate to ~6%. Assuming Omega_m=1 and Omega_lambda=0, the most significant deviation we find from the Hubble law is an outwards flow of (6.6+/-2.2)% inside a sphere of radius 70 Mpc/h as would be produced by a void of ~20% underdensity surrounded by a dense shell. This shell roughly coincides with the local Great Walls. Monte Carlo analyses, using Gaussian errors or bootstrap resampling, show the probability for chance occurrence of this result out of a pure Hubble flow to be ~2%. The monopole could be contaminated by higher moments of the velocity field, especially a quadrupole, which are not properly probed by the current limited sky coverage. The void would be less significant if Omega_m is low and Omega_lambda is high. It would be more significant if one outlier is removed from the sample, or if the size of the void is constrained a-priori. This putative void is not in significant conflict with any of the standard cosmological scenarios. It suggests that the Hubble constant as determined within 70 Mpc/h could be overestimated by ~6% and the local value of Omega may be underestimated by ~20%. While the present evidence for a local void is marginal in this data set, the analysis shows that the accumulation of SNe Ia distances will soon provide useful constraints on elusive and important aspects of regional cosmic dynamics.Comment: 21 pages, 3 figures. Slightly revised version. To appear in ApJ, 503, Aug. 20, 199

Using SN Ia Light Curve Shapes to Measure The Hubble Constant

We present an empirical method which uses visual band light curve shapes (LCS) to estimate the luminosity of type Ia supernovae (SN Ia). This method is first applied to a ``training set'' of 8 SN Ia light curves with independent distance estimates to derive the correlation between the LCS and the luminosity. We employ a linear estimation algorithm of the type developed by Rybicki and Press (1992). The result is similar to that obtained by Hamuy et al. (1995a) with the advantage that LCS produces quantitative error estimates for the distance. We then examine the light curves for 13 SN Ia to determine the LCS distances of these supernovae. The Hubble diagram constructed using these LCS distances has a remarkably small dispersion of $\sigma_V$ = 0.21 mag. We use the light curve of SN 1972E and the Cepheid distance to NGC 5253 to derive $67 \pm 7$ km s$^{-1}$ Mpc$^{-1}$ for the Hubble constant.Comment: 10 pages + 2 figures, Postscript file includes text and figures, Submitted to Ap.J. (Letters), Harvard-Smithsonian Center for Astrophysics Preprint 499