1,319 research outputs found

    Capabilities for the Future: TSA Strategy

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    TSA is responsible for securing a transportation sector that contributes 8.6% of the U.S. gross domestic product and represents 12 million jobs and $18 trillion in annual value of goods moved

    Extremely narrow spectrum of GRB110920A: further evidence for localised, subphotospheric dissipation

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    Much evidence points towards that the photosphere in the relativistic outflow in GRBs plays an important role in shaping the observed MeV spectrum. However, it is unclear whether the spectrum is fully produced by the photosphere or whether a substantial part of the spectrum is added by processes far above the photosphere. Here we make a detailed study of the γ\gamma-ray emission from single pulse GRB110920A which has a spectrum that becomes extremely narrow towards the end of the burst. We show that the emission can be interpreted as Comptonisation of thermal photons by cold electrons in an unmagnetised outflow at an optical depth of τ20\tau \sim 20. The electrons receive their energy by a local dissipation occurring close to the saturation radius. The main spectral component of GRB110920A and its evolution is thus, in this interpretation, fully explained by the emission from the photosphere including localised dissipation at high optical depths.Comment: 14 pages, 11 figures, accepted to MNRA

    Surface excitonic emission and quenching effects in ZnO nanowire/nanowall systems: limiting effects on device potential.

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    We report ZnO nanowire/nanowall growth using a two-step vapour phase transport method on a-plane sapphire. X-ray diffraction and scanning electron microscopy data establish that the nanostructures are vertically well-aligned with c-axis normal to the substrate, and have a very low rocking curve width. Photoluminescence data at low temperatures demonstrate the exceptionally high optical quality of these structures, with intense emission and narrow bound exciton linewidths. We observe a high energy excitonic emission at low temperatures close to the band-edge which we assign to the surface exciton in ZnO at ~ 3.366 eV, the first time this feature has been reported in ZnO nanorod systems. This assignment is consistent with the large surface to volume ratio of the nanowire systems and indicates that this large ratio has a significant effect on the luminescence even at low temperatures. The band-edge intensity decays rapidly with increasing temperature compared to bulk single crystal material, indicating a strong temperature-activated non-radiative mechanism peculiar to the nanostructures. No evidence is seen of the free exciton emission due to exciton delocalisation in the nanostructures with increased temperature, unlike the behaviour in bulk material. The use of such nanostructures in room temperature optoelectronic devices appears to be dependent on the control or elimination of such surface effects

    IVOA Recommendation: VOTable Format Definition Version 1.3

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    This document describes the structures making up the VOTable standard. The main part of this document describes the adopted part of the VOTable standard; it is followed by appendices presenting extensions which have been proposed and/or discussed, but which are not part of the standard

    Discovery of a New Nearby Star

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    We report the discovery of a nearby star with a very large proper motion of 5.06 +/- 0.03 arcsec/yr. The star is called SO025300.5+165258 and referred to herein as HPMS (high proper motion star). The discovery came as a result of a search of the SkyMorph database, a sensitive and persistent survey that is well suited for finding stars with high proper motions. There are currently only 7 known stars with proper motions > 5 arcsec/yr. We have determined a preliminary value for the parallax of 0.43 +/- 0.13 arcsec. If this value holds our new star ranks behind only the Alpha Centauri system (including Proxima Centauri) and Barnard's star in the list of our nearest stellar neighbors. The spectrum and measured tangential velocity indicate that HPMS is a main-sequence star with spectral type M6.5. However, if our distance measurement is correct, the HPMS is underluminous by 1.2 +/- 0.7 mag.Comment: 5 pages, 3 figures. Submitted to ApJ Letter

    Mapping the HealthPathways literature: a scoping review protocol

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    Objective: This scoping review will identify what literature exists on HealthPathways and make suggestions for the direction of future HealthPathways research. Background: HealthPathways is a free to access, password protected online tool containing practical, easy to use, localised clinical and referral information that is primarily aimed at GPs. HealthPathways originated in Canterbury, New Zealand in 2008. Since this time the program has spread and is being used in 50 health systems across New Zealand, Australia, and the United Kingdom (Streamliners, 2022a). Despite such large spread of the program there has been relatively little literature published on the utility, usefulness and cost-effectiveness of HealthPathways. This scoping review aims to identify and describe all current HealthPathways literature and make recommendations for the direction of future HealthPathways research. Methods: The Joanna Briggs Institute (JBI) methodology will be used to develop the scoping review. Databases included in the search include MEDLINE (PubMEd), Embase, CINAHL, Web of Science, Google Scholar, Emerald and Cochrane. The inclusion criteria are studies and grey literature on HealthPathways that are published in English, with no time limit. Grey literature will be identified through searching relevant credible organisations and websites. All results will be entered into Covidence to be assessed by two reviewers against a set tool. The PRISMA extension for scoping reviews will be used for reporting. Ethics approval is not required as only published information will be used. The research will be disseminated through publication in an open access peer reviewed journal. Conclusions: This protocol is published to make the process for the review transparent and replicable. The scoping review will highlight the extent of evidence that exists on HealthPathways and may provide direction for decision making and future research

    Exploring the spread and scale of a web-based clinical decision support portal in Sydney, Australia, during COVID-19: a case study

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    Purpose HealthPathways is an online decision support portal, primarily aimed at General Practitioners (GPs), that provides easy to access and up to date clinical, referral and resource pathways. It is free to access, with the intent of providing the right care, at the right place, at the right time. This case study focuses on the experience and learnings of a HealthPathways program in metropolitan Sydney during the COVID-19 pandemic. It reviews the team's program management responses and looks at key factors that have facilitated the spread and scale of HealthPathways. Design/methodology/approach Available data and experiences of two HealthPathways program managers were used to recount events and aspects influencing spread and scale. Findings The key factors for successful spread and scale are a coordinated response, the maturity of the HealthPathways program, having a single source of truth, high level governance, leadership, collaboration, flexible funding and ability to make local changes where required. Originality/value There are limited published articles on HealthPathways. The focus of spread and scale of HealthPathways during COVID-19 is unique

    Is the biology of breast cancer changing? A study of hormone receptor status 1984-1986 and 1996-1997

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    Using archived tumours, those from 1984-1986 and 1996-1997 underwent immunohistochemistry for hormone receptors and grade analysis. A significant shift towards more ER-positive and low-grade disease was found; this appears to reflect screening practices, but could still influence survival
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