7,425 research outputs found

    High-Speed Rail Projects in the United States: Identifying the Elements of Success-Part 2, MTI 06-03

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    In August 2005, the Mineta Transportation Institute issued the report, High-Speed Rail Projects in the United States: Identifying the Elements for Success. The report noted that since the 1960s, highspeed ground transportation (HSGT) has “held the promise of fast, convenient, and environmentally sound travel for distances between 40 and 600 miles.” After briefly discussing the different experiences with HSGT between the United States and its Asian and European counterparts, the report proceeded to review three U.S. cases—Florida, California, and the Pacific Northwest—as a means for identifying lessons learned for successfully implementing high-speed rail (HSR) in the United States. This report is, in essence, volume 2 of the previous study. Also using a comparative case study approach, this effort adds to the earlier work with three additional cases—the Chicago Hub, the Keystone Corridor, and the Northeast Corridor (NEC). As with the earlier report, the goal of this study is to identify lessons learned for successfully implementing HSR in the United States. Given the early stages of most of these projects, “success” is defined by whether a given HSR project is still actively pursuing development or funding. However, in the case of the Northeast Corridor, a fuller discussion of success is provided since HSR has been implemented on that corridor for some time now

    SU(N) Coherent States

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    We generalize Schwinger boson representation of SU(2) algebra to SU(N) and define coherent states of SU(N) using 2(2N−1−1)2(2^{N-1}-1) bosonic harmonic oscillator creation and annihilation operators. We give an explicit construction of all (N-1) Casimirs of SU(N) in terms of these creation and annihilation operators. The SU(N) coherent states belonging to any irreducible representations of SU(N) are labelled by the eigenvalues of the Casimir operators and are characterized by (N-1) complex orthonormal vectors describing the SU(N) manifold. The coherent states provide a resolution of identity, satisfy the continuity property, and possess a variety of group theoretic properties.Comment: 25 pages, LaTex, no figure

    Risk models and scores for type 2 diabetes: Systematic review

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    This article is published under a Creative Commons Attribution Non Commercial (CC BY-NC 3.0) licence that allows reuse subject only to the use being non-commercial and to the article being fully attributed (http://creativecommons.org/licenses/by-nc/3.0).Objective - To evaluate current risk models and scores for type 2 diabetes and inform selection and implementation of these in practice. Design - Systematic review using standard (quantitative) and realist (mainly qualitative) methodology. Inclusion - criteria Papers in any language describing the development or external validation, or both, of models and scores to predict the risk of an adult developing type 2 diabetes. Data sources - Medline, PreMedline, Embase, and Cochrane databases were searched. Included studies were citation tracked in Google Scholar to identify follow-on studies of usability or impact. Data extraction - Data were extracted on statistical properties of models, details of internal or external validation, and use of risk scores beyond the studies that developed them. Quantitative data were tabulated to compare model components and statistical properties. Qualitative data were analysed thematically to identify mechanisms by which use of the risk model or score might improve patient outcomes. Results - 8864 titles were scanned, 115 full text papers considered, and 43 papers included in the final sample. These described the prospective development or validation, or both, of 145 risk prediction models and scores, 94 of which were studied in detail here. They had been tested on 6.88 million participants followed for up to 28 years. Heterogeneity of primary studies precluded meta-analysis. Some but not all risk models or scores had robust statistical properties (for example, good discrimination and calibration) and had been externally validated on a different population. Genetic markers added nothing to models over clinical and sociodemographic factors. Most authors described their score as “simple” or “easily implemented,” although few were specific about the intended users and under what circumstances. Ten mechanisms were identified by which measuring diabetes risk might improve outcomes. Follow-on studies that applied a risk score as part of an intervention aimed at reducing actual risk in people were sparse. Conclusion - Much work has been done to develop diabetes risk models and scores, but most are rarely used because they require tests not routinely available or they were developed without a specific user or clear use in mind. Encouragingly, recent research has begun to tackle usability and the impact of diabetes risk scores. Two promising areas for further research are interventions that prompt lay people to check their own diabetes risk and use of risk scores on population datasets to identify high risk “hotspots” for targeted public health interventions.Tower Hamlets, Newham, and City and Hackney primary care trusts and National Institute of Health Research

    From Black Holes to Glueballs: The QCD_3 Tensor Glueball at Strong Coupling

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    A strong coupling calculation of glueball masses based on the duality between supergravity and Yang-Mills theory is presented. Earlier work is extended to non-zero spin. Fluctuations in the gravitational metric lead to the 2^{++} state on the leading Pomeron trajectory with a mass relation: m(0^{++}) < m(2^{++}) < m(1^{-+}). Contrary to expectation, the mass of our new 0^{++} state (m^2=5.4573) associated with the graviton is smaller than the mass of the 0~++{\tilde 0}^{++} state (m^2=11.588) from the dilaton, which in fact is exactly degenerate with the tensor 2^{++}.Comment: 3 pages, 1 figure, Talk at Lattice 99 by R. Browe

    Numerical studies in partial differential equations of elliptic type

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    On Understanding Indian Philosophical Thinking

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    Professor Potter interprets Indian philosophy as mainly concerned with moksa or transcendental freedom. Professor Riepe offers a Marxist interpretation of Indian philosophy. The aim of this paper is to identify the strengths and limitations of each of these two views

    Sufficient conditions for generalized Sakaguchi type functions of order ÎČ

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    In this paper, we obtain some sufficient conditions for generalized Sakaguchi type function of order ÎČ, defined on the open unit disk. Many interesting outcomes of our results are also calculated.Publisher's Versio

    Nonmarket Valuations of Accidental Oil Spills: A Survey of Economic and Legal Principles

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    This paper presents an overview of legal and economic theories used to assess liability and damages for loss of nonmarket goods arising from an accidental oil spill. Several different economic methods used for quantifying values are discussed and critiqued. Also reviewed are the fundamental legal doctrines that permit individuals and public agencies to seek compensation for these damages. To illustrate the applicability of these economic and legal theories, two case studies arc presented and evaluated in terms of the principles presented earlier.Environmental Economics and Policy, International Relations/Trade, Research Methods/ Statistical Methods, Resource /Energy Economics and Policy, Risk and Uncertainty,
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