22,452 research outputs found

    African-American Males in Prison: Are they Doing Time or is the Time Doing Them?

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    African-American males comprise a disproportionate percentage of the individuals imprisoned in State correctional institutions across the United States. The purpose of this paper is to describe how incarceration affects African-American males. The author recommends more rigorous and systematic analysis of the prison experience, and how it affects the mental, physical, and social well-being of African-American males. Given this nation\u27s commitment to using imprisonment as the principal means for punishing convicted felons, it is imperative that society ascertain the social, psychological, and economic effects of such confinement on millions of African-American males

    Entropy reduction of quantum measurements

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    It is observed that the entropy reduction (the information gain in the initial terminology) of an efficient (ideal or pure) quantum measurement coincides with the generalized quantum mutual information of a q-c channel mapping an a priori state to the corresponding posteriori probability distribution of the outcomes of the measurement. This observation makes it possible to define the entropy reduction for arbitrary a priori states (not only for states with finite von Neumann entropy) and to study its analytical properties by using general properties of the quantum mutual information. By using this approach one can show that the entropy reduction of an efficient quantum measurement is a nonnegative lower semicontinuous concave function on the set of all a priori states having continuous restrictions to subsets on which the von Neumann entropy is continuous. Monotonicity and subadditivity of the entropy reduction are also easily proved by this method. A simple continuity condition for the entropy reduction and for the mean posteriori entropy considered as functions of a pair (a priori state, measurement) is obtained. A characterization of an irreducible measurement (in the Ozawa sense) which is not efficient is considered in the Appendix.Comment: 21 pages, minor corrections have been mad

    Appeal Waivers and the Future of Sentencing Policy

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    This paper is the first empirical analysis of appeal waivers clauses in plea agreements by which defendants waive their rights to appellate and postconviction review. Based on interviews and an analysis of data coded from 971 randomly selected cases sentenced under the United States Sentencing Guidelines, the study\u27s findings include (1) in nearly two-thirds of the cases settled by plea agreement, the defendants waived their rights to review; (2) the frequency of waiver varies substantially among the circuits, and among districts within circuits; (3) the government appears to provide some sentencing concessions more frequently to defendants who sign waivers than to defendants who do not, including agreeing to C pleas (binding sentencing terms), downward departures, safety-valve credits, and a variety of stipulations; (4) many defendants who waive their rights to review obtain clauses in their agreements that limit their exposure to unexpected negative results at sentencing; (5) some defendants appear to receive neither greater certainty nor leniency in return for signing wide-open and unlimited waivers of their rights to review; (6) three-quarters of the defendants who waived appeal also waived collateral review, and of these, fewer than one-third preserved the right to raise a claim of ineffective assistance; and (7) waivers have been enforced to bar a variety of claims, including claims of ineffective assistance at sentencing and assertions of constitutional violations under Blakely and Booker. The observed trend of increased use of stipulations combined with no review raises the risk that sentences not in compliance with the law can proliferate without scrutiny. The uneven practice of trading sentencing concessions for waivers among cases and courts also suggests that waivers are undercutting efforts to advance consistency in federal sentencing

    Production of long-lived atomic vapor inside high-density buffer gas

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    Atomic vapor of four different paramagnetic species: gold, silver, lithium, and rubidium, is produced and studied inside several buffer gases: helium, nitrogen, neon, and argon. The paramagnetic atoms are injected into the buffer gas using laser ablation. Wires with diameters 25 μ\mum, 50 μ\mum, and 100 μ\mum are used as ablation targets for gold and silver, bulk targets are used for lithium and rubidium. The buffer gas cools and confines the ablated atoms, slowing down their transport to the cell walls. Buffer gas temperatures between 20 K and 295 K, and densities between 101610^{16} cm−3^{-3} and 2×10192\times10^{19} cm−3^{-3} are explored. Peak paramagnetic atom densities of 101110^{11} cm−3^{-3} are routinely achieved. The longest observed paramagnetic vapor density decay times are 110 ms for silver at 20 K and 4 ms for lithium at 32 K. The candidates for the principal paramagnetic-atom loss mechanism are impurities in the buffer gas, dimer formation and atom loss on sputtered clusters.Comment: Some minor editorial changes and corrections, added reference

    Modulation of endoglin expression in islets of langerhans by VEGF reveals a novel regulator of islet endothelial cell function

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    BACKGROUND: Endoglin/CD105 is an auxiliary receptor for transforming growth factor-β with established roles in vascular remodelling. It has recently been shown that heterozygous endoglin deficiency in mice decreases insulin secretion in an animal model of obesity, highlighting a potential role for endoglin in the regulation of islet function. We have previously identified two different populations of endoglin expressing cells in human and mouse islets which are: (i) endothelial cells (ECs) and (ii) islet mesenchymal stromal cells. The contribution of islet EC endoglin expression to islet development and sensitivity to VEGF is unknown and is the focus of this study. RESULTS: In vitro culture of mouse islets with VEGF164 for 48 h increased endoglin mRNA levels above untreated controls but VEGF did not modulate VEGFR2, CD31 or CD34 mRNA expression or islet viability. Removal of EC-endoglin expression in vivo reduced islet EC area but had no apparent effect on islet size or architecture. CONCLUSION: EC-specific endoglin expression in islets is sensitive to VEGF and plays partial roles in driving islet vascular development, however such regulation appears to be distinct to mechanisms required to modulate islet viability and size

    Demographic Understanding of Volunteerism

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    A large sample of volunteers from a midwestern city chapter of the American Red Cross were studied to identify demographic correlates of the reasons given for volunteering. The findings suggest that the reasons people give for doing volunteer work are conditioned by their age, sex, and marital status. Implications for volunteer programs and future research are discussed

    Omega-3 Fatty Acids Improve Recovery, whereas Omega-6 Fatty Acids Worsen Outcome, after Spinal Cord Injury in the Adult Rat

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    Spinal cord injury (SCI) is a cause of major neurological disability, and no satisfactory treatment is currently available. Evidence suggests that polyunsaturated fatty acids (PUFAs) could target some of the pathological mechanisms that underlie damage after SCI. We examined the effects of treatment with PUFAs after lateral spinal cord hemisection in the rat. The ω-3 PUFAs α-linolenic acid and docosahexaenoic acid (DHA) injected 30 min after injury induced significantly improved locomotor performance and neuroprotection, including decreased lesion size and apoptosis and increased neuronal and oligodendrocyte survival. Evidence showing a decrease in RNA/DNA oxidation suggests that the neuroprotective effect of ω-3 PUFAs involved a significant antioxidant function. In contrast, animals treated with arachidonic acid, an ω-6 PUFA, had a significantly worse outcome than controls. We confirmed the neuroprotective effect of ω-3 PUFAs by examining the effects of DHA treatment after spinal cord compression injury. Results indicated that DHA administered 30 min after spinal cord compression not only greatly increased survival of neurons but also resulted in significantly better locomotor performance for up to 6 weeks after injury. This report shows a striking difference in efficacy between the effects of treatment with ω-3 and ω-6 PUFAs on the outcome of SCI, with ω-3 PUFAs being neuroprotective and ω-6 PUFAs having a damaging effect. Given the proven clinical safety of ω-3 PUFAs, our observations show that these PUFAs have significant therapeutic potential in SCI. In contrast, the use of preparations enriched in ω-6 PUFAs after injury could worsen outcome after SCI

    Anomalous single production of the fourth SM family quarks at Tevatron

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    Possible single productions of fourth family u_{4} and d_{4} quarks via anomalous q_{4}qV interactions at Tevatron are studied. Signature of such processes are discussed and compared with the recent results from Tevatron.Comment: 6 pages, 1 figure, 4 table
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