2,415 research outputs found

    Warm HCN, C2H2, and CO in the disk of GV Tau

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    We present the first high-resolution, ground-based observations of HCN and C2H2 toward the T Tauri binary star system GV Tau. We detected strong absorption due to HCN nu_3 and weak C2H2 (nu_3 and nu_2 + (nu_4 + nu_5)^0_+) absorption toward the primary (GV Tau S) but not the infrared companion. We also report CO column densities and rotational temperatures, and present abundances relative to CO of HCN/CO ~0.6% and C2H2/CO ~1.2% and an upper limit for CH4/CO < 0.37% toward GV Tau S. Neither HCN nor C2H2 were detected toward the infrared companion and results suggest that abundances may differ between the two sources.Comment: 23 pages, 6 figures, accepted by Ap

    Toward a Just Model of Pretrial Release: A History of Bail Reform and a Prescription for What\u27s Next

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    The criminal justice system is in the midst of the “third wave” of bail reform in the United States. The current movement aims to end the ingrained practices of wealth-based discrimination in pretrial administration. The authors—civil rights attorneys who have litigated the issue of cash bond in Cook County, Illinois—have been on the front lines of this policy shift. From this vantage, we conduct a historical analysis of modern-day bail reform efforts in the “first” and “second” waves of bail reform, and examine the impact of these reforms on incarceration rates and racial disparities in the justice system. We explain how these earlier efforts both influenced and created the conditions for the third wave reforms that are now underway, including a “groundswell” of class action litigation that seeks to minimize pretrial detention by breathing new life into longstanding principles of equal protection and due process. We then analyze the impact of these third wave reforms nationwide, while using Cook County as a case study. The results suggest reason for both optimism and caution, particularly in jurisdictions where advocates have been willing to trade a more expansive scheme of preventive detention for the elimination of the cash bail system. We conclude with observations in support of a just system of pretrial release—one that relies neither on money bond nor on preventive detention measures. This system is one in which the vast majority of the presumptively innocent people charged with offenses are immediately released back into their communities. It is a system in which courts provide services rather than onerous conditions, to minimize failures to appear in court, mitigate recidivism, and ensure that communities are not decimated by unconstitutional pretrial detention. While this model is not without some societal risk, we contend it is the only tolerable outcome under our constitutional system

    Augmented saddle point formulation of the steady-state Stefan--Maxwell diffusion problem

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    We investigate structure-preserving finite element discretizations of the steady-state Stefan--Maxwell diffusion problem which governs diffusion within a phase consisting of multiple species. An approach inspired by augmented Lagrangian methods allows us to construct a symmetric positive definite augmented Onsager transport matrix, which in turn leads to an effective numerical algorithm. We prove inf-sup conditions for the continuous and discrete linearized systems and obtain error estimates for a phase consisting of an arbitrary number of species. The discretization preserves the thermodynamically fundamental Gibbs--Duhem equation to machine precision independent of mesh size. The results are illustrated with numerical examples, including an application to modelling the diffusion of oxygen, carbon dioxide, water vapour and nitrogen in the lungs.Comment: 27 pages, 5 figure

    Structural electroneutrality in Onsager-Stefan-Maxwell transport with charged species

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    We present a method to embed local electroneutrality within Onsager-Stefan-Maxwell electrolytic-transport models, circumventing their formulation as differential systems with an algebraic constraint. Flux-explicit transport laws are formulated for general multicomponent electrolytes, in which the conductivity, component diffusivities, and transference numbers relate to Stefan-Maxwell coefficients through invertible matrix calculations. A construction we call a `salt-charge basis' implements Guggenheim's transformation of species electrochemical potentials into combinations describing a minimal set of neutral components, leaving a unique combination associated with electricity. Defining conjugate component concentrations and fluxes that preserve the structures of the Gibbs function and energy dissipation retains symmetric Onsager reciprocal relations. The framework reproduces Newman's constitutive laws for binary electrolytes and the Pollard-Newman laws for molten salts; we also propose laws for salt solutions in two-solvent blends, such as lithium-ion-battery electrolytes. Finally, we simulate a potentiostatic Hull cell containing a non-ideal binary electrolyte with concentration-dependent properties

    Propensity Score-Matched Analysis of Open Surgical and Endovascular Repair for Type B Aortic Dissection

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    Objective. To identify national outcomes of thoracic endovascular aortic repair (TEVAR) for type B aortic dissections (TBADs). Methods. The Nationwide Inpatient Sample database was examined from 2005 to 2008 using ICD-9 codes to identify patients with TBAD who underwent TEVAR or open surgical repair. We constructed separate propensity models for emergently and electively admitted patients and calculated mortality and complication rates for propensity score-matched cohorts of TEVAR and open repair patients. Results. In-hospital mortality was significantly higher following open repair than TEVAR (17.5% versus 10.8%, P = .045) in emergently admitted TBAD. There was no in-hospital mortality difference between open repair and TEVAR (5.6% versus 3.3%, P = .464) for elective admissions. Hospitals performing thirty or more TEVAR procedures annually had lower mortality for emergent TBAD than hospitals with fewer than thirty procedures. Conclusions. TEVAR produces better in-hospital outcomes in emergent TBAD than open repair, but further longitudinal analysis is required

    Assessment of ICESat-2 Ice Sheet Surface Heights, Based on Comparisons over the Interior of the Antarctic Ice Sheet

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    We collected kinematic Global Navigation Satellite Systems (GNSS) surface height data, on a 750km groundbased traverse of the flat interior of the Antarctic ice sheet, for comparison with Ice, Cloud, and Land Elevation Satellite2 (ICESat2) surface heights. Vertical errors in the GNSS data are estimated to be 5.6 cm, comparable to results from a previous traverse and with yeartoyear comparisons. Comparisons of the GNSS heights and 6 months of ICESat2 ATL03 photonbased heights and ATL06 segmentbased heights indicate that the accuracy and precision of ICESat2 data are comparable to that of results from the ICESat mission: ATL03 is currently accurate to better than 5 cm with better than 13 cm of surface measurement precision, while ATL06 is currently accurate to better than 3 cm with better than 9 cm of surface measurement precision

    Air pollution, deprivation and health: Understanding relationships to add value to local air quality management policy and practice in Wales, UK

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    © The Author 2016. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. Background Air pollution exposure reduces life expectancy. Air pollution, deprivation and poor-health status combinations can create increased and disproportionate disease burdens. Problems and solutions are rarely considered in a broad public health context, but doing so can add value to air quality management efforts by reducing air pollution risks, impacts and inequalities. Methods An ecological study assessed small-area associations between air pollution (nitrogen dioxide and particulate matter), deprivation status and health outcomes in Wales, UK. Results Air pollution concentrations were highest in 'most' deprived areas. When considered separately, deprivation-health associations were stronger than air pollution-health associations. Considered simultaneously, air pollution added to deprivation-health associations; interactions between air pollution and deprivation modified and strengthened associations with all-cause and respiratory disease mortality, especially in 'most' deprived areas where most-vulnerable people lived and where health needs were greatest. Conclusion There is a need to reduce air pollution-related risks for all. However, it is also the case that greater health gains can result from considering local air pollution problems and solutions in the context of wider health-determinants and acting on a better understanding of relationships. Informed and co-ordinated air pollution mitigation and public health action in high deprivation and pollution areas can reduce risks and inequalities. To achieve this, greater public health integration and collaboration in local air quality management policy and practice is needed

    Sequential and Spontaneous Star Formation Around the Mid-Infrared Halo HII Region KR 140

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    We use 2MASS and MSX infrared observations, along with new molecular line (CO) observations, to examine the distribution of young stellar objects (YSOs) in the molecular cloud surrounding the halo HII region KR 140 in order to determine if the ongoing star-formation activity in this region is dominated by sequential star formation within the photodissociation region (PDR) surrounding the HII region. We find that KR 140 has an extensive population of YSOs that have spontaneously formed due to processes not related to the expansion of the HII region. Much of the YSO population in the molecular cloud is concentrated along a dense filamentary molecular structure, traced by C18O, that has not been erased by the formation of the exciting O star. Some of the previously observed submillimetre clumps surrounding the HII region are shown to be sites of recent intermediate and low-mass star formation while other massive starless clumps clearly associated with the PDR may be the next sites of sequential star formation.Comment: Accepted for publication in MNRAS, 8 pages, 10 figure
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