624 research outputs found

    Two fast X-ray transients in archival Chandra data

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    We present the discovery of two new X-ray transients in archival Chandra data. The first transient, XRT 110103, occurred in January 2011 and shows a sharp rise of at least three orders of magnitude in count rate in less than 10 s, a flat peak for about 20 s and decays by two orders of magnitude in the next 60 s. We find no optical or infrared counterpart to this event in preexisting survey data or in an observation taken by the SIRIUS instrument at the Infrared Survey Facility 2.1 yr after the transient, providing limiting magnitudes of J>18.1, H>17.6 and Ks>16.3. This event shows similarities to the transient previously reported in Jonker et al. which was interpreted as the possible tidal disruption of a white dwarf by an intermediate mass black hole. We discuss the possibility that these transients originate from the same type of event. If we assume these events are related a rough estimate of the rates gives 1.4*10^5 per year over the whole sky with a peak 0.3-7 keV X-ray flux greater than 2*10^-10 erg cm^-2 s^-1 . The second transient, XRT 120830, occurred in August 2012 and shows a rise of at least three orders of magnitude in count rate and a subsequent decay of around one order of magnitude all within 10 s, followed by a slower quasi-exponential decay over the remaining 30 ks of the observation. We detect a likely infrared counterpart with magnitudes J=16.70+/-0.06, H=15.92+/-0.04 and Ks=15.37+/-0.06 which shows an average proper motion of 74+/-19 milliarcsec per year compared to archival 2MASS observations. The JHKs magnitudes, proper motion and X-ray flux of XRT 120830 are consistent with a bright flare from a nearby late M or early L dwarf.Comment: Accepted for publication in MNRAS, 6 pages, 5 figure

    Incorporating Animal Movement Into Distance Sampling

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    Distance sampling is a popular statistical method to estimate the density of wild animal populations. Conventional distance sampling represents animals as fixed points in space that are detected with an unknown probability that depends on the distance between the observer and the animal. Animal movement can cause substantial bias in density estimation. Methods to correct for responsive animal movement exist, but none account for nonresponsive movement independent of the observer. Here, an explicit animal movement model is incorporated into distance sampling, combining distance sampling survey data with animal telemetry data. Detection probability depends on the entire unobserved path the animal travels. The intractable integration over all possible animal paths is approximated by a hidden Markov model. A simulation study shows themethod to be negligibly biased (\u3c5%) in scenarioswhere conventional distance sampling overestimates abundance by up to 100%. The method is applied to line transect surveys (1999– 2006) of spotted dolphins (Stenella attenuata) in the eastern tropical Pacific where abundance is shown to be positively biased by 21% on average, which can have substantial impact on the population dynamics estimated from these abundance estimates and on the choice of statistical methodology applied to future surveys. Supplementary materials for this article, including a standardized description of the materials available for reproducing the work, are available as an online supplement

    ShortNotice and Unannounced Survey Methods: Literature review

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    The Commission’s role is to lead and coordinate national improvements in the safety and quality of health care. The Commission works in partnership with the Australian Government, state and territory governments and the private sector to achieve a safe and high -qu ality, sustainable health system. In doing so, the Commission also works closely with patients, carers, clinicians, managers, policymakers and healthcare organisations. The Commission is responsible under the National Health Reform Act 2011 for the formul ation of standards relating to health care safety and quality matters and for formulating and coordinating national models of accreditation for health service organisations. The Commission developed the National Safety and Quality Health Service (NSQHS) Standards in consultation with the Australian Government , state and territory governments, technical experts and other stakeholders. They aim to protect the public from harm and to improve the quality of health service provision. To become accredited, health service organisations must pass assessments to show they have implemented the NSQHS Standards. The assessments are conducted by independent accrediting agencies, approved by the Commission, as part of the AHSSQA Scheme. However, state and territory regulators and chief executives of health service organisations have raised concerns about several aspects of the accreditation process

    Attestation by Governing Bodies: Literature review

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    Preface This preface was written by the Australian Commission on Safety and Quality in Health Care (the Commission) to provide context and background to the report which follows, Attestation by Governing Bodies: Literature review. The Commission contracted the University of Technology Sydney (UTS) to prepare the literature review, as part of the review of the Australian Health Service Safety and Quality Accreditation (AHSSQA) Scheme. Background The Commission’s role is to lead and coordinate national improvements in the safety and quality of health care. The Commission works in partnership with the Australian Government, state and territory governments and the private sector to achieve a safe and high-quality, sustainable health system. In doing so, the Commission also works closely with patients, carers, clinicians, managers, policymakers and healthcare organisations. The Commission is responsible under the National Health Reform Act 2011 for the formulation of standards relating to healthcare safety and quality matters and for formulating and coordinating national models of accreditation for health service organisations. The Commission developed the National Safety and Quality Health Service (NSQHS) Standards in consultation with the Australian Government, state and territory governments, technical experts and stakeholders. They aim to protect the public from harm and to improve the quality of health service provision. To become accredited, health service organisations must pass assessments to show they have implemented the NSQHS Standards. The assessments are conducted by independent accrediting agencies approved by the Commission as part of the AHSSQA Scheme. However, state and territory regulators and chief executives of health service organisations have raised concerns about several aspects of the accreditation process. The Commission is undertaking a review to update and improve the accreditation process. In May 2017, the Commission contracted four literature reviews to provide an evidence base to inform the Commission’s review of the AHSSQA Scheme. The reviews explored the potential use of the following methods to improve the veracity of health service organisations: • Attestation by a governing body • Short-notice and unannounced surveys • Patient journey and tracer methodologies • Safety culture assessment. The report that follows this preface presents the findings of a literature review that explored the potential use of attestation by governing bodies during accreditation of health service organisations. Key findings The report on attestation by governing bodies includes a definition of attestation, a review of the evidence of the effectiveness of attestation by governing bodies as part of accreditation in healthcare, and examples of the use of attestation in practice

    Patient Journey and Tracer Methodologies: Literature review

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    Preface This preface was written by the Australian Commission on Safety and Quality in Health Care (the Commission) to provide context and background to the report which follows, Patient Journey and Tracer Methodologies: Literature review. The Commission contracted the University of Technology Sydney (UTS) to prepare the literature review, as part of the review of the Australian Health Service Safety and Quality Accreditation (AHSSQA) Scheme. Background The Commission’s role is to lead and coordinate national improvements in the safety and quality of health care. The Commission works in partnership with the Australian Government, state and territory governments and the private sector to achieve a safe and high-quality, sustainable health system. In doing so, the Commission also works closely with patients, carers, clinicians, managers, policymakers and healthcare organisations. The Commission developed the National Safety and Quality Health Service (NSQHS) Standards in consultation with the Australian Government, state and territory governments, technical experts and stakeholders. They aim to protect the public from harm and to improve the quality of health service provision. To become accredited, health service organisations must pass assessments to show they have implemented the NSQHS Standards. The assessments are conducted by independent accrediting agencies, approved by the Commission, as part of the AHSSQA Scheme. However, state and territory regulators and chief executives of health service organisations have raised concerns about several aspects of the accreditation process. The Commission is undertaking a review to update and improve the accreditation process. In May 2017, the Commission contracted four literature reviews to provide an evidence base to inform the Commission’s review of the AHSSQA Scheme. The reviews explored the potential use of the following methods to improve the veracity of health service organisations: • Attestation by a governing body • Short-notice and unannounced surveys • Patient journey and tracer methodologies • Safety culture assessment. The report that follows this preface presents the findings of a literature review that explored the potential use of patient journey and tracer methodologies as part of health service organisation accreditation. Key findings The key findings of the report on patient journey and tracer methodologies (hereafter referred to as ‘patient journey methodologies’) are discussed according to the evidence of its effectiveness and considerations for its use in the AHSSQA Scheme

    An In Vitro Study Comparing Limited to Full Cementation of Polyethylene Glenoid Components

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    BACKGROUND: Glenoid component survival is critical to good long-term outcomes in total shoulder arthroplasty. Optimizing the fixation environment is paramount. The purpose of this study was to compare two glenoid cementing techniques for fixation in total shoulder arthroplasty. METHODS: Sixteen cadaveric specimens were randomized to receive peg-only cementation (CPEG) or full back-side cementation (CBACK). Physiological cyclic loading was performed and implant displacement was recorded using an optical tracking system. The cement mantle was examined with micro-computed tomography before and after cyclic loading. RESULTS: Significantly greater implant displacement away from the inferior portion of the glenoid was observed in the peg cementation group when compared to the fully cemented group during the physiological loading. The displacement was greatest at the beginning of the loading protocol and persisted at a diminished rate during the remainder of the loading protocol. Micro-CT scanning demonstrated that the cement mantle remained intact in both groups and that three specimens in the CBACK group demonstrated microfracturing in one area only. DISCUSSION: Displacement of the CPEG implants away from the inferior subchondral bone may represent a suboptimal condition for long-term implant survival. Cement around the back of the implant is suggested to improve initial stability of all polyethylene glenoid implants. CLINICAL RELEVANCE: Full cementation provides greater implant stability when compared to limited cementation techniques for insertion of glenoid implants. Loading characteristics are more favorable when cement is placed along the entire back of the implant contacting the subchondral bone

    Dynamic ductile to brittle transition in a one-dimensional model of viscoplasticity

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    We study two closely related, nonlinear models of a viscoplastic solid. These models capture essential features of plasticity over a wide range of strain rates and applied stresses. They exhibit inelastic strain relaxation and steady flow above a well defined yield stress. In this paper, we describe a first step in exploring the implications of these models for theories of fracture and related phenomena. We consider a one dimensional problem of decohesion from a substrate of a membrane that obeys the viscoplastic constitutive equations that we have constructed. We find that, quite generally, when the yield stress becomes smaller than some threshold value, the energy required for steady decohesion becomes a non-monotonic function of the decohesion speed. As a consequence, steady state decohesion at certain speeds becomes unstable. We believe that these results are relevant to understanding the ductile to brittle transition as well as fracture stability.Comment: 10 pages, REVTeX, 12 postscript figure

    Sociology’s missed opportunity: John Stuart-Glennie’s lost theory of the moral revolution, also known as the axial age

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    In 1873, 75 years before Karl Jaspers published his theory of the Axial Age in 1949, unknown to Jaspers and to contemporary scholars today, Scottish folklorist John Stuart Stuart-Glennie elaborated the first fully developed and nuanced theory of what he termed “the Moral Revolution” to characterize the historical shift emerging roughly around 600 BCE in a variety of civilizations, most notably ancient China, India, Judaism, and Greece, as part of a broader critical philosophy of history. He continued to write on the idea over decades in books and articles and also presented his ideas to the fledgling Sociological Society of London in 1905, which were published the following year in the volume Sociological Papers, Volume 2. This article discusses Stuart-Glennie’s ideas on the moral revolution in the context of his philosophy of history, including what he termed “panzooinism”; ideas with implications for contemporary debates in theory, comparative history, and sociology of religion. It shows why he should be acknowledged as the originator of the theory now known as the axial age, and also now be included as a significant sociologist in the movement toward the establishment of sociology
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