And Justice for Some: Differential Treatment of Youth of Color in the Justice System

This report details the accumulated disadvantage for youth of color as they move through the juvenile justice system and, too often, into the adult system

Youth Violence Myths and Realities: A Tale of Three Cities

A study of media coverage of youth violence, actual crime data, and interviews with committed youth and the professionals that work with them

El crédito comercial y la crisis crediticia: un análisis descriptivo en Europa; Reino Unido y España

El uso de crédito comercial como forma de financiar el corto plazo ha aumentando en los últimos años, las grandes empresas utilizan más días del que necesitan para realizar los pagos a las pequeñas empresas, lo que provoca fatales consecuencias financieras para los proveedores. Estos problemas financieros no son nuevos, pero con la restricción pronunciada del crédito los problemas se agudizan debido a que el uso masivo del crédito comercial repercute negativamente en los proveedores cuya insolvencia y riesgo de quiebra aumentan. En este trabajo se revisan de forma descriptiva el uso del crédito comercial en la crisis crediticia. Las principales contribuciones de la ponencia son dos. En primer lugar, mostrar las consecuencias financieras por la utilización del crédito comercial y, concretamente, en la crisis crediticia, y cómo el gobierno de Reino Unido desarrolla políticas públicas de pago para reducir el efecto negativo de los impagados. En segundo lugar, estudiar y comparar la situación de los países europeos en términos de pago a los proveedores y, en particular, el caso de Reino Unido, pero también el caso Español.The use of trade credit as a short-term financing is increasing in the last years; large firms use more days to pay small firms than they need, which causes financial fatal consequences to suppliers. These financial problems are not new, but with the credit crunch they are coming up because the massive use of the trade credit impacts negatively on suppliers whose insolvency and bankruptcy risks increase. In this paper we review in a descriptive way the use of trade credit in the credit crunch. The main contributions of the paper are two. Firstly, we show the financial consequences of the use of trade credit, and specifically in credit crisis, and how UK government develop public payment policies to reduce the negative effect of delete payments. Secondly, we study and compare the situation of European countries in terms of payment to suppliers, and in particular the case of UK, but also Spanish case

Dynamical perturbations around an extreme mass ratio inspiral near resonance

Extreme mass ratio inspirals (EMRIs) -- systems with a compact object orbiting a much more massive (e.g., galactic center) black hole -- are of interest both as a new probe of the environments of galactic nuclei, and their waveforms are a precision test of the Kerr metric. This work focuses on the effects of an external perturbation due to a third body around an EMRI system. This perturbation will affect the orbit most significantly when the inner body crosses a resonance with the outer body, and result in a change of the conserved quantities (energy, angular momentum, and Carter constant) or equivalently of the actions, which results in a subsequent phase shift of the waveform that builds up over time. We present a general method for calculating the changes in action during a resonance crossing, valid for generic orbits in the Kerr spacetime. We show that these changes are related to the gravitational waveforms emitted by the two bodies (quantified by the amplitudes of the Weyl scalar $\psi_4$ at the horizon and at $\infty$) at the frequency corresponding to the resonance. This allows us to compute changes in the action variables for each body, without directly computing the explicit metric perturbations, and therefore we can carry out the computation by calling an existing black hole perturbation theory code. We show that our calculation can probe resonant interactions in both the static and dynamical limit. We plan to use this technique for future investigations of third-body effects in EMRIs and their potential impact on waveforms for LISA.Comment: 19 pages, 5 figures, 1 table, to be submitted to PR

Utilizing a Learning Management System to Support Access to Study Abroad: A Program Evaluation at the University of Denver

This doctoral research project investigated issues of access to study abroad at the University of Denver (DU). The study evaluated the use of the learning management system Canvas during Fall 2017, in preparation for student applications for study abroad during Fall 2018. The evaluation utilized qualitative data from focus groups with students and families, interviews with higher education professionals and analytics data on the usage of Canvas. The findings identified that the usage of Canvas during Fall 2017 was low in comparison to the number of individuals who applied to study abroad and was focused on the preparation for the application to the program. Various suggestions for improvement were generated by the participants of the study and these suggestions provided support for the recommendations to the OIE staff. The framework of Critical Disability Studies with a focus on the emerging Disability Media Studies (DMS) was used to investigate how the distribution, content and organization of Canvas impacted access to study abroad by underrepresented populations at DU. The recommendations for the improvement of the delivery of the Study Abroad Handbook in Canvas were developed to support the work of the OIE staff and to be immediately actionable. These action steps originated from the discussions and contributions of the OIE staff, DU professionals, students, families and myself. The recommendations ranged from content re-organization, increased access to study abroad advising staff, testimonials from previous study abroad participants, study abroad information in Spanish to support family awareness and a revisiting of all online tools used by the OIE. A major recommendation is on the creation of a theory of change or learning map for the complete study abroad experience along with the establishment of an annual evaluation program

Effect of dust in circumgalactic haloes on the cosmic shear power spectrum

Weak gravitational lensing is a powerful statistical tool for probing the growth of cosmic structure and measuring cosmological parameters. However, as shown by studies such as M\'enard et al. (2010), dust in the circumgalactic region of haloes dims and reddens background sources. In a weak lensing analysis, this selects against sources behind overdense regions; since there is more structure in overdense regions, we will underestimate the amplitude of density perturbations $\sigma_8$ if we do not correct for the effects of circumgalactic dust. To model the dust distribution we employ the halo model. Assuming a fiducial dust mass profile based on measurements from M\'enard et al. (2010), we compute the ratio $Z$ of the systematic error to the statistical error for a survey similar to the Nancy Grace Roman Space Telescope reference survey (2000 deg$^2$ area, single-filter effective source density 30 galaxies arcmin$^{-2}$). For a waveband centered at $1580$ nm ($H$-band), we find that $Z_{H} = 0.37$. For a similar survey with waveband centered at $620$ nm ($r$-band), we also computed $Z_{r} = 2.8$. Within our fiducial dust model, since $Z_{r} > 1$, the systematic effect of dust will be significant on weak lensing image surveys. We also computed the dust bias on the amplitude of the power spectrum, $\sigma_{8}$, and found it to be for each waveband $\Delta \sigma_8/\sigma_8 = -3.1\times 10^{-4}$ ($H$ band) or $-2.2\times 10^{-3}$ ($r$ band) if all other parameters are held fixed (the forecast Roman statistical-only error $\sigma(\sigma_8)/\sigma_8$ is $9\times 10^{-4}$).Comment: 17 pages, 8 figure

Human sperm ion channel (dys)function:implications for fertilization

BACKGROUND: Intensive research on sperm ion channels has identified members of several ion channel families in both mouse and human sperm. Gene knock-out studies have unequivocally demonstrated the importance of the calcium and potassium conductances in sperm for fertility. In both species, the calcium current is carried by the highly complex cation channel of sperm (CatSper). In mouse sperm, the potassium current has been conclusively shown to be carried by a channel consisting of the pore forming subunit SLO3 and auxiliary subunit leucine-rich repeat-containing 52 (LRRC52). However, in human sperm it is controversial whether the pore forming subunit of the channel is composed of SLO3 and/or SLO1. Deciphering the role of the proton-specific Hv1 channel is more challenging as it is only expressed in human sperm. However, definitive evidence for a role in, and importance for, human fertility can only be determined through studies using clinical samples.OBJECTIVE AND RATIONALE: This review aims to provide insight into the role of sperm ion channels in human fertilization as evidenced from recent studies of sperm from infertile men. We also summarize the key discoveries from mouse ion channel knock-out models and contrast the properties of mouse and human CatSper and potassium currents. We detail the evidence for, and consequences of, defective ion channels in human sperm and discuss hypotheses to explain how defects arise and why affected sperm have impaired fertilization potential.SEARCH METHODS: Relevant studies were identified using PubMed and were limited to ion channels that have been characterized in mouse and human sperm. Additional notable examples from other species are included as appropriate.OUTCOMES: There are now well-documented fundamental differences between the properties of CatSper and potassium channel currents in mouse and human sperm. However, in both species, sperm lacking either channel cannot fertilize in vivo and CatSper-null sperm also fail to fertilize at IVF. Sperm-lacking potassium currents are capable of fertilizing at IVF, albeit at a much lower rate. However, additional complex and heterogeneous ion channel dysfunction has been reported in sperm from infertile men, the causes of which are unknown. Similarly, the nature of the functional impairment of affected patient sperm remains elusive. There are no reports of studies of Hv1 in human sperm from infertile men.WIDER IMPLICATIONS: Recent studies using sperm from infertile men have given new insight and critical evidence supporting the supposition that calcium and potassium conductances are essential for human fertility. However, it should be highlighted that many fundamental questions remain regarding the nature of molecular and functional defects in sperm with dysfunctional ion channels. The development and application of advanced technologies remains a necessity to progress basic and clinical research in this area, with the aim of providing effective screening methodologies to identify and develop treatments for affected men in order to help prevent failed ART cycles. Conversely, development of drugs that block calcium and/or potassium conductances in sperm is a plausible strategy for producing sperm-specific contraceptives.</p