2,744 research outputs found
The Great Pretenders Among the ULX Class
The recent discoveries of pulsed X-ray emission from three ultraluminous
X-ray (ULX) sources have finally enabled us to recognize a subclass within the
ULX class: the great pretenders, neutron stars (NSs) that appear to emit X-ray
radiation at isotropic luminosities ~erg~s~erg~s only because their emissions are strongly beamed toward
our direction and our sight lines are offset by only a few degrees from their
magnetic-dipole axes. The three known pretenders appear to be stronger emitters
than the presumed black holes of the ULX class, such as Holmberg II \& IX X-1,
IC10 X-1, and NGC300 X-1. For these three NSs, we have adopted a single
reasonable assumption, that their brightest observed outbursts unfold at the
Eddington rate, and we have calculated both their propeller states and their
surface magnetic-field magnitudes. We find that the results are not at all
different from those recently obtained for the Magellanic Be/X-ray pulsars: the
three NSs reveal modest magnetic fields of about 0.3-0.4~TG and beamed
propeller-line X-ray luminosities of ~erg~s,
substantially below the Eddington limit.Comment: To appear in Research in Astronomy and Astrophysic
An ultrahigh-speed digitizer for the Harvard College Observatory astronomical plates
A machine capable of digitizing two 8 inch by 10 inch (203 mm by 254 mm)
glass astrophotographic plates or a single 14 inch by 17 inch (356 mm by 432
mm) plate at a resolution of 11 microns per pixel or 2309 dots per inch (dpi)
in 92 seconds is described. The purpose of the machine is to digitize the
\~500,000 plate collection of the Harvard College Observatory in a five year
time frame. The digitization must meet the requirements for scientific work in
astrometry, photometry, and archival preservation of the plates. This paper
describes the requirements for and the design of the subsystems of the machine
that was developed specifically for this task.Comment: 12 pages, 9 figures, 1 table; presented at SPIE (July, 2006) and
published in Proceeding
The H1 Forward Track Detector at HERA II
In order to maintain efficient tracking in the forward region of H1 after the
luminosity upgrade of the HERA machine, the H1 Forward Track Detector was also
upgraded. While much of the original software and techniques used for the HERA
I phase could be reused, the software for pattern recognition was completely
rewritten. This, along with several other improvements in hit finding and
high-level track reconstruction, are described in detail together with a
summary of the performance of the detector.Comment: Minor revision requested by journal (JINST) edito
The clinical and cost-effectiveness of a Victim Improvement Package (VIP) for the reduction of chronic symptoms of depression or anxiety in older victims of common crime (the VIP trial): study protocol for a randomised controlled trial.
BACKGROUND: Older people are vulnerable to sustained high levels of psychosocial distress following a crime. A cognitive behavioural therapy (CBT)-informed psychological therapy, the Victim Improvement Package (VIP) may aid recovery. The VIP trial aims to test the clinical and cost-effectiveness of the VIP for alleviating depressive and anxiety symptoms in older victims of crime. METHODS/DESIGN: People aged 65 years or more who report being a victim of crime will be screened by Metropolitan Police Service Safer Neighbourhood Teams within a month of the crime for distress using the Patient Health Questionnaire-2 and the Generalised Anxiety Disorder-2. Those who screen positive will be signposted to their GP for assistance, and re-screened at 3 months. Participants who screen positive for depression and/or anxiety at re-screening are randomised to a CBT informed VIP added to treatment as usual (TAU) compared to TAU alone. The intervention consists of 10 individual 1-h sessions, delivered weekly by therapists from the mental health charity Mind. The primary outcome measure is the Beck Depression Inventory-II (BDI-II) and the Beck Anxiety Inventory (BAI), used as a composite measure, assessed at 6 months after the crime (post therapy) with a 9-month post-crime follow-up. Secondary outcome measures include the EQ-5D, and a modified Client Service Receipt Inventory. A total of 226 participants will be randomised VIP:TAU with a ratio 1:1, in order to detect a standardised difference of at least 0.5 between groups, using a mixed-effects linear-regression model with 90% power and a 5% significance level (adjusting for therapist clustering and potential drop-out). A cost-effectiveness analysis will incorporate intervention costs to compare overall health care costs and quality of life years between treatment arms. An embedded study will examine the impact of past trauma and engagement in safety behaviours and distress on the main outcomes. DISCUSSION: This trial should provide data on the clinical and cost-effectiveness of a CBT-informed psychological therapy for older victims of crime with anxiety and/or depressive symptoms and should demonstrate a model of integrated cross-agency working. Our findings should provide evidence for policy-makers, commissioners and clinicians responding to the needs of older victims of crime. TRIAL REGISTRATION: International Standard Randomised Controlled Trials Number, ID: ISRCTN16929670. Registered on 3 August 2016
High Speed Visible Light Communication Using Blue GaN Laser Diodes
GaN-based laser diodes have been developed over the last 20 years making them desirable for many security and defence applications, in particular, free space laser communications. Unlike their LED counterparts, laser diodes are not limited by their carrier lifetime which makes them attractive for high speed communication, whether in free space, through fiber or underwater. Gigabit data transmission can be achieved in free space by modulating the visible light from the laser with a pseudo-random bit sequence (PRBS), with recent results approaching 5 Gbit/s error free data transmission. By exploiting the low-loss in the blue part of the spectrum through water, data transmission experiments have also been conducted to show rates of 2.5 Gbit/s underwater. Different water types have been tested to monitor the effect of scattering and to see how this affects the overall transmission rate and distance. This is of great interest for communication with unmanned underwater vehicles (UUV) as the current method using acoustics is much slower and vulnerable to interception. These types of laser diodes can typically reach 50-100 mW of power which increases the length at which the data can be transmitted. This distance could be further improved by making use of high power laser arrays. Highly uniform GaN substrates with low defectivity allow individually addressable laser bars to be fabricated. This could ultimately increase optical power levels to 4 W for a 20-emitter array. Overall, the development of GaN laser diodes will play an important part in free space optical communications and will be vital in the advancement of security and defence applications
A developmental evaluation to enhance stakeholder engagement in a wide-scale interactive project disseminating quality improvement data: Study protocol for a mixed-methods study
© 2017 Article author(s). All rights reserved. Introduction: Bringing together continuous quality improvement (CQI) data from multiple health services offers opportunities to identify common improvement priorities and to develop interventions at various system levels to achieve large-scale improvement in care. An important principle of CQI is practitioner participation in interpreting data and planning evidence-based change. This study will contribute knowledge about engaging diverse stakeholders in collaborative and theoretically informed processes to identify and address priority evidence-practice gaps in care delivery. This paper describes a developmental evaluation to support and refine a novel interactive dissemination project using aggregated CQI data from Aboriginal and Torres Strait Islander primary healthcare centres in Australia. The project aims to effect multilevel system improvement in Aboriginal and Torres Strait Islander primary healthcare. Methods and analysis: Data will be gathered using document analysis, online surveys, interviews with participants and iterative analytical processes with the research team. These methods will enable real-time feedback to guide refinements to the design, reports, tools and processes as the interactive dissemination project is implemented. Qualitative data from interviews and surveys will be analysed and interpreted to provide in-depth understanding of factors that influence engagement and stakeholder perspectives about use of the aggregated data and generated improvement strategies. Sources of data will be triangulated to build up a comprehensive, contextualised perspective and integrated understanding of the project's development, implementation and findings. Ethics and dissemination: The Human Research Ethics Committee (HREC) of the Northern Territory Department of Health and Menzies School of Health Research (Project 2015-2329), the Central Australian HREC (Project 15-288) and the Charles Darwin University HREC (Project H15030) approved the study. Dissemination will include articles in peer-reviewed journals, policy and research briefs. Results will be presented at conferences and quality improvement network meetings. Researchers, clinicians, policymakers and managers developing evidence-based system and policy interventions should benefit from this research
Determinants of access to chronic illness care: a mixed-methods evaluation of a national multifaceted chronic disease package for Indigenous Australians
Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/ OBJECTIVES: Indigenous Australians have a disproportionately high burden of chronic illness, and relatively poor access to healthcare. This paper examines how a national multicomponent programme aimed at improving prevention and management of chronic disease among Australian Indigenous people addressed various dimensions of access.DESIGN: Data from a place-based, mixed-methods formative evaluation were analysed against a framework that defines supply and demand-side dimensions to access. The evaluation included 24 geographically bounded 'sentinel sites' that included a range of primary care service organisations. It drew on administrative data on service utilisation, focus group and interview data on community members' and service providers' perceptions of chronic illness care between 2010 and 2013.SETTING: Urban, regional and remote areas of Australia that have relatively large Indigenous populations.PARTICIPANTS: 670 community members participated in focus groups; 374 practitioners and representatives of regional primary care support organisations participated in in-depth interviews.RESULTS: The programme largely addressed supply-side dimensions of access with less focus or impact on demand-side dimensions. Application of the access framework highlighted the complex inter-relationships between dimensions of access. Key ongoing challenges are achieving population coverage through a national programme, reaching high-need groups and ensuring provision of ongoing care.CONCLUSIONS: Strategies to improve access to chronic illness care for this population need to be tailored to local circumstances and address the range of dimensions of access on both the demand and supply sides. These findings highlight the importance of flexibility in national programme guidelines to support locally determined strategies
Problem-oriented policing in England and Wales: barriers and facilitators
Evidence shows that the application of problem-oriented policing can be effective in reducing a wide range of crime and public safety issues, but that the approach is challenging to implement and sustain. This article examines police perceptions and experiences regarding organisational barriers to and facilitators of the implementation and delivery of problem-oriented policing. Drawing on surveys of (n = 4141) and interviews with (n = 86) police personnel from 19 police forces in England and Wales, we identify five key barriers and facilitators to problem-oriented policing: leadership and governance, capacity, organisational structures and infrastructure, partnership working and organisational culture. These factors provide important indicators for what police organisations need to do, or need to avoid, if they are to successfully embed and deliver problem-oriented policing. The article generates critical information about the processes that drive change in police organisations and offers recommendations for police managers who may wish to implement or develop problem-oriented policing. The paper also proposes a research agenda aimed at addressing evidence gaps in our understanding of the implementation and sustenance of problem-oriented policing
Wide-scale continuous quality improvement: A study of stakeholders' use of quality of care reports at various system levels, and factors mediating use
© 2019 Laycock, Bailie, Percival, Matthews, Cunningham, Harvey, Copley, Patel and Bailie. Introduction: Increasing the use of evidence in healthcare policy and practice requires greater understanding of how stakeholders use evidence to inform policy, refine systems and change practice. Drawing on implementation theory, we have used system-focused participatory research to engage diverse stakeholders in using aggregated continuous quality improvement (CQI) data from Australian Indigenous primary health care settings to identify priority evidence-practice gaps, barriers/enablers and strategies for improvement. This article reports stakeholders' use or intended use of evidence at various levels of the system, and factors mediating use. Material and Methods: Interviews were undertaken with a purposeful sample of 30 healthcare stakeholders in different roles, organization types and settings in one Australian jurisdiction and with national participants, as part of the project's developmental evaluation. Qualitative data were analyzed to identify themes and categories relating to use of evidence. Results: Context-specific aggregated CQI data that were relatable to the diverse professional roles and practices provided an effective starting point for sharing perspectives, generating practice-based evidence and mobilizing evidence-use. Interviewees perceived the co-produced findings as applicable at different levels and useful for planning, policy development, supporting best practice and reflection, capacity strengthening and developing new research. Factors mediating use were commitment to best practice; the credibility of the evidence and its perceived relevance to work roles, contexts and decision needs; report format and language; facilitation and communication; competing work pressures and the organizational environment for change. Conclusions: This study found that primary health care stakeholders used evidence on quality of care for a variety of purposes. This could be linked to the interactive research processes used to engage stakeholders in different roles and settings in interpreting data, sharing and generating knowledge. Findings indicate that system-based participatory research using CQI data and iterative, interactive and systematic CQI-based methods can be applied at scale to support concurrent action for healthcare improvement at different system levels. Factors known to influence implementation should be addressed within the research design to optimize evidence use. Further research is needed to explore the utility of interactive dissemination for engaging healthcare stakeholders in informing policy and system change
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