10,051 research outputs found
High-Speed Rail Projects in the United States: Identifying the Elements of Success-Part 2, MTI 06-03
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
We generalize Schwinger boson representation of SU(2) algebra to SU(N) and
define coherent states of SU(N) using 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
Nonmarket Valuations of Accidental Oil Spills: A Survey of Economic and Legal Principles
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,
Discourses Of Prejudice In The professions: The Case Of Sign Languages
There is no evidence that learning a natural human language is cognitively harmful to children. To the contrary, multilingualism has been argued to be beneficial to all. Nevertheless, many professionals advise the parents of deaf children that their children should not learn a sign language during their early years, despite strong evidence across many research disciplines that sign languages are natural human languages. Their recommendations are based on a combination of misperceptions about (1) the difficulty of learning a sign language, (2) the effects of bilingualism, and particularly bimodalism, (3) the bona fide status of languages that lack a written form, (4) the effects of a sign language on acquiring literacy, (5) the ability of technologies to address the needs of deaf children and (6) the effects that use of a sign language will have on family cohesion. We expose these misperceptions as based in prejudice and urge institutions involved in educating professionals concerned with the healthcare, raising and educating of deaf children to include appropriate information about first language acquisition and the importance of a sign language for deaf children. We further urge such professionals to advise the parents of deaf children properly, which means to strongly advise the introduction of a sign language as soon as hearing loss is detected
Drug development: Lessons from nature.
Natural products have been acknowledged for numerous years as a vital source of active ingredients in therapeutic agents. In particular, the use of active ingredients derived from plants for use in microbial natural products have long been used before the dawn of modern medicine. From ancient times, the efficacy of natural products has been associated with the chemistry, biochemistry and synthetic activities of natural products. Thus, with scientific advancement in modern molecular and cellular biology, analytical chemistry and pharmacology, the unique properties of these natural products are being harnessed in order to exploit the chemical and structural diversity and biodiversity of these types of products in relation to their therapeutic effect. Often, new molecules of interest in drug design units focus on the rearrangement of chemical entities or structural isomers of naturally occurring products in order to generate new molecules; these may be formulated into clinically useful therapies
Bubbling solutions, entropy enhancement and the fuzzball proposal
In this short note we explain the main idea of the work done in
arXiv:0804.4487[hep-th] and arXiv:0812.2942[hep-th]. We present a family of
black hole microstates, the bubbling solutions. We then explain how supertubes
placed in such backgrounds have their entropy enhanced by the presence of the
background dipole charges. This indicates this could account for a large amount
in the entropy of the three charge black hole.Comment: 2 pages, contribution to the Cargese 2008 proceedings: Theory and
Particle Physics: the LHC perspective and beyon
Risk models and scores for type 2 diabetes: Systematic review
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
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