1,034 research outputs found

    Precision of the determination of focal depth from the spectral ratio of Love/Rayleigh surface waves

    Get PDF
    The precision with which the focal depth may be determined using Love/Rayleigh-wave spectral ratios depends on the accuracy of the models for Earth structure and for source mechanism used in the focal depth calculations. Estimates of the precision of the focal depth determination are obtained using the partial derivatives of Love/Rayleigh spectral ratios with respect to the parameters: focal depth, shear velocity, dip angle, and slip angle. We find that errors caused by imprecise knowledge of any of these parameters can be important in practice

    Chiasma

    Get PDF
    Newspaper reporting on events at the Boston University School of Medicine in the 1960s

    LocalControl: An R Package for Comparative Safety and Effectiveness Research

    Get PDF
    The LocalControl R package implements novel approaches to address biases and confounding when comparing treatments or exposures in observational studies of outcomes. While designed and appropriate for use in comparative safety and effectiveness research involving medicine and the life sciences, the package can be used in other situations involving outcomes with multiple confounders. LocalControl is an open-source tool for researchers whose aim is to generate high quality evidence using observational data. The package implements a family of methods for non-parametric bias correction when comparing treatments in observational studies, including survival analysis settings, where competing risks and/or censoring may be present. The approach extends to bias-corrected personalized predictions of treatment outcome differences, and analysis of heterogeneity of treatment effect-sizes across patient subgroups

    Using Nuclear Magnetic Resonance (NMR) Metabolic Profiling to Distinguish Herds of Bighorn Sheep

    Get PDF
    The objective of this study was to determine if nuclear magnetic resonance (NMR) metabolic profiling has the potential to serve as a management tool for evaluating herds of bighorn (Ovis canadensis) sheep. Two-hundred and forty bighorn sheep serum samples from 13 herds located in Montana and Wyoming were processed for NMR spectra, profiled for small molecule metabolites using Chenomx®, and then analyzed with MetaboAnalyst (v3.0). Fifty-six small molecule metabolites were identified in ungulate serum.  To determine if NMR metabolic profiles can distinguish herds that are geographically distinct with access to different nutritional resources, herds collected in December were compared to herds collected in March. Partial least square discriminant analysis (PLS-DA) indicated a clear, majority separation of metabolic shifts with minor overlaps. Biomarker analysis identified 15 potential biomarkers from the compounds with variables of importance (VIP) scores greater than 1.0. These molecules enabled us to identify ‘significantly’ important metabolic pathways that discriminate herds sampled in December and herds sampled in March. Key biomarkers resulting from the pathway analysis, included: 2-oxoisocaproate, choline, tyrosine, creatinine, and trimethylamine n-oxide. To determine if metabolic profiling can distinguish individual herds within a month, herds in December, January and March were compared to a domestic, Rambouillet ewes (control) sampled during the sample months.  PLS-DA of all herds showed clear metabolic shifts and complete separation between each individual herd and the control ewes for each month. Potential biomarkers for herds within a season that were found to be good discriminants for the December herds included: trimethylamine n-oxide and sarcosine; for January herds included: creatinine and asparagine; and, for March herd included, creatinine. Through identification of small molecule metabolites, it is possible to discriminate herds from each other within and between seasons. These biomarkers represent a potential panel of metabolites that may be used for assessing nutritional status, environmental stress, and herd health through the identification of significantly important metabolic pathways related to energy and protein balance

    State of Vermont Health Care Financing Plan Beginning Calendar Year 2017 Analysis

    Get PDF
    This report, prepared for the Vermont Agency of Administration, details the costs and coverage of a single-payer system in Vermont, and explained that the state must develop new financing mechanisms that raise $1.6 billion to fund single-payer. It was produced in partnership with Wakely Consulting Group Inc. However, on December 17, 2014, Gov. Peter Shumlin announced that now is not the right time to overhaul health care financing and delivery in Vermont

    Oxygen Abundances in Two Metal-Poor Subgiants from the Analysis of the 6300 A Forbidden O I Line

    Full text link
    Recent LTE analyses (Israelian et al. 1998 and Bosegaard et al. 1999) of the OH bands in the optical-ultraviolet spectra of nearby metal-poor subdwarfs indicate that oxygen abundances are generally higher than those previously determined. The difference increases with decreasing metallicity and reaches delta([O/Fe]) ~ +0.6 dex as [Fe/H] approaches -3.0. Employing high resolution (R = 50000), high S/N (~ 250) echelle spectra of the two stars found by Israelian et al. (1998) to have the highest [O/Fe]-ratios, viz, BD +23 3130 and BD +37 1458, we conducted abundance analyses based on about 60 Fe I and 7-9 Fe II lines. We determined from Kurucz LTE models the values of the stellar parameters, as well as abundances of Na, Ni, and the traditional alpha-elements, independent of the calibration of color vs TeffT_{eff} scales. We determined oxygen abundances from spectral synthesis of the stronger line (6300 A) of the [O I] doublet. The syntheses of the [O I] line lead to smaller values of [O/Fe], consistent with those found earlier among halo field and globular cluster giants. We obtain [O/Fe] = +0.35 +/- 0.2 for BD +23 3130 and +0.50 +/- 0.2 for BD +37 1458. In the former, the [O I] line is very weak (~ 1 mA), so that the quoted [O/Fe] value may in reality be an upper limit. Therefore in these two stars a discrepancy exists between the [O/Fe]- ratios derived from [O I] and the OH feature, and the origin of this difference remains unclear. Until the matter is clarified, we suggest it is premature to conclude that the ab initio oxygen abundances of old, metal-poor stars need to be revised drastically upward.Comment: 38 pages, 5 tables, 14 figures To appear in July 1999 AJ Updated April 16, 1999. Fixed typo

    Four problems with global carbon markets: a critical review

    Get PDF
    This article offers a critique of global carbon markets and trading, with a special focus on the Clean Development Mechanism of the Kyoto Protocol. It explores problems with the use of tradable permits to address climate change revolving around four areas: homogeneity, justice, gaming, and information. Homogeneity problems arise from the non-linear nature of climate change and sensitivity of emissions, which complicate attempts to calculate carbon offsets. Justice problems involve issues of dependency and the concentration of wealth among the rich, meaning carbon trading often counteracts attempts to reduce poverty. Gaming problems include pressures to promote high-volume, least-cost projects and the consequences of emissions leakage. Information problems encompass transaction costs related to carbon trading and market participation and the comparatively weak institutional capacity of project evaluators

    (1,0) superconformal models in six dimensions

    Get PDF
    We construct six-dimensional (1,0) superconformal models with non-abelian gauge couplings for multiple tensor multiplets. A crucial ingredient in the construction is the introduction of three-form gauge potentials which communicate degrees of freedom between the tensor multiplets and the Yang-Mills multiplet, but do not introduce additional degrees of freedom. Generically these models provide only equations of motions. For a subclass also a Lagrangian formulation exists, however it appears to exhibit indefinite metrics in the kinetic sector. We discuss several examples and analyze the excitation spectra in their supersymmetric vacua. In general, the models are perturbatively defined only in the spontaneously broken phase with the vev of the tensor multiplet scalars serving as the inverse coupling constants of the Yang-Mills multiplet. We briefly discuss the inclusion of hypermultiplets which complete the field content to that of superconformal (2,0) theories.Comment: 30 pages, v2: Note, some comments and references adde

    Dynamic Versus Static Oxidation of Nb/Al-AlOx_x/Nb Trilayer

    Full text link
    High quality Nb-based superconductor-insulator-superconductor (SIS) junctions with Al oxide (AlOx_x) tunnel barriers grown from Al overlayers are widely reported in the literature. However, the thin barriers required for high critical current density (Jc_c) junctions exhibit defects that result in significant subgap leakage current that is detrimental for many applications. High quality, high-Jc_c junctions can be realized with AlNx_x barriers, but control of Jc_c is more difficult than with AlOx_x. It is therefore of interest to study the growth of thin AlOx_x barriers with the ultimate goal of achieving high quality, high-Jc_c AlOx_x junctions. In this work, 100\%\ O2_2 and 2\%\ O2_2 in Ar gas mixtures are used both statically and dynamically to grow AlOx_x tunnel barriers over a large range of oxygen exposures. In situ ellipsometry is used for the first time to extensively measure AlOx_x tunnel barrier growth in real time, revealing a number of unexpected patterns. Finally, a set of test junction wafers was fabricated that exhibited the well-known dependence of Jc_c on oxygen exposure (E) in order to further validate the experimental setup
    corecore