1,349 research outputs found

    Giant Stark effect in the emission of single semiconductor quantum dots

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    We study the quantum-confined Stark effect in single InAs/GaAs quantum dots embedded within a AlGaAs/GaAs/AlGaAs quantum well. By significantly increasing the barrier height we can observe emission from a dot at electric fields of -500 kV/cm, leading to Stark shifts of up to 25 meV. Our results suggest this technique may enable future applications that require self-assembled dots with transitions at the same energy

    A qualitative exploration of the effect of visual field loss on daily life in home-dwelling stroke survivors

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    Objective: To explore the effect of visual field loss on the daily life of community-dwelling stroke survivors. Design: A qualitative interview study. Participants: Adult stroke survivors with visual field loss of at least six months’ duration. Methods: Semi-structured interviews were conducted with a non-purposive sample of 12 stroke survivors in their own homes. These were recorded, transcribed verbatim and analyzed with the framework method, using an inductive approach. Results: Two key analytical themes emerged. ‘Perception, experience and knowledge’ describes participant’s conflicted experience of having knowledge of their impaired vision but lacking perception of that visual field loss and operating under the assumption that they were viewing an intact visual scene when engaged in activities. Inability to recognize and deal with visual difficulties, and experiencing the consequences, contributed to their fear and loss of self-confidence. ‘Avoidance and adaptation’ were two typologies of participant response to visual field loss. Initially, all participants consciously avoided activities. Some later adapted to vision loss using self-directed head and eye scanning techniques. Conclusions: Visual field loss has a marked impact on stroke survivors. Stroke survivors lack perception of their visual loss in everyday life, resulting in fear and loss of confidence. Activity avoidance is a common response, but in some, it is replaced by self-initiated adaptive techniques

    Adherence to

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    (MWM) for palliative care has prioritized data collection efforts for evaluating quality in clinical practice. How these measures can be implemented across diverse clinical settings using point-of-care data collection on quality is unknown.To evaluate the implementation of MWM measures by exploring documentation of quality measure adherence across six diverse clinical settings inherent to palliative care practice.We deployed a point-of-care quality data collection system, the Quality Data Collection Tool, across five organizations within the Palliative Care Research Cooperative Group. Quality measures were recorded by clinicians or assistants near care delivery.During the study period, 1989 first visits were included for analysis. Our population was mostly white, female, and with moderate performance status. About half of consultations were seen on hospital general floors. We observed a wide range of adherence. The lowest adherence involved comprehensive assessments during the first visit in hospitalized patients in the intensive care unit (2.71%); the highest adherence across all settings, with an implementation of >95%, involved documentation of management of moderate/severe pain. We observed differences in adherence across clinical settings especially with MWM Measure #2 (Screening for Physical Symptoms, range 45.7%–81.8%); MWM Measure #5 (Discussion of Emotional Needs, range 46.1%–96.1%); and MWM Measure #6 (Documentation of Spiritual/Religious Concerns, range 0–69.6%).Variations in clinician documentation of adherence to MWM quality measures are seen across clinical settings. Additional studies are needed to better understand benchmarks and acceptable ranges for adherence tailored to various clinical settings

    Leveraging the Health and Retirement Study To Advance Palliative Care Research

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    Background: The critical need to expand and develop the palliative care evidence base was recently highlighted by the Journal of Palliative Medicine's series of articles describing the Research Priorities in Geriatric Palliative Care. The Health and Retirement Study (HRS) is uniquely positioned to address many priority areas of palliative care research. This nationally representative, ongoing, longitudinal study collects detailed survey data every 2 years, including demographics, health and functional characteristics, information on family and caregivers, and personal finances, and also conducts a proxy interview after each subject's death. The HRS can also be linked with Medicare claims data and many other data sources, e.g., U.S. Census, Dartmouth Atlas of Health Care. Setting: While the HRS offers innumerable research opportunities, these data are complex and limitations do exist. Therefore, we assembled an interdisciplinary group of investigators using the HRS for palliative care research to identify the key palliative care research gaps that may be amenable to study within the HRS and the strengths and weaknesses of the HRS for each of these topic areas. Conclusion: In this article we present the work of this group as a potential roadmap for investigators contemplating the use of HRS data for palliative care research.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140117/1/jpm.2013.0648.pd

    Tunable Indistinguishable Photons From Remote Quantum Dots

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    Single semiconductor quantum dots have been widely studied within devices that can apply an electric field. In the most common system, the low energy offset between the InGaAs quantum dot and the surrounding GaAs material limits the magnitude of field that can be applied to tens of kVcm^-1, before carriers tunnel out of the dot. The Stark shift experienced by the emission line is typically 1 meV. We report that by embedding the quantum dots in a quantum well heterostructure the vertical field that can be applied is increased by over an order of magnitude whilst preserving the narrow linewidths, high internal quantum efficiencies and familiar emission spectra. Individual dots can then be continuously tuned to the same energy allowing for two-photon interference between remote, independent, quantum dots

    Prevalence and Implications of Frailty in Older Adults With Incident Inflammatory Bowel Diseases : A Nationwide Cohort Study

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    BACKGROUND AND AIMS: We aimed to compare the risk of frailty in older adults with incident inflammatory bowel disease (IBD) and matched non-IBD comparators and assess the association between frailty and future hospitalizations and mortality. METHODS: In a cohort of patients with incident IBD ≥60 years of age from 2007 to 2016 in Sweden identified using nationwide registers, we defined frailty using Hospital Frailty Risk Score. We compared prevalence of frailty in patients with IBD with age, sex, place of residency- and calendar year-matched population comparators. In the IBD cohort, we used Cox proportional hazards modeling to examine the associations between frailty risk and hospitalizations or mortality. RESULTS: We identified 10,590 patients with IBD, 52% female with a mean age of 71 years of age, matched to 103,398 population-based comparators. Among patients with IBD, 39% had no risk for frailty, 49% had low risk for frailty, and 12% had higher risk for frailty. Mean Hospital Frailty Risk Score was 1.9 in IBD and 0.9 in matched comparators (P < .01). Older adults with IBD at higher risk for frailty had a 20% greater risk for mortality at 3 years compared with those who were not frail. Compared with nonfrail older patients with IBD, patients at higher risk for frailty had increased mortality (hazard ratio [HR], 3.22, 95% confidence interval [CI], 2.86-3.61), all-cause hospitalization (HR, 2.42; 95% CI, 2.24-2.61), and IBD-related hospitalization (HR, 1.50; 95% CI, 1.35-1.66). These associations were not attenuated after adjusting for comorbidities. CONCLUSIONS: Frailty is more prevalent in older adults with IBD than in matched comparators. Among older patients with IBD, frailty is associated with increased risk for hospitalizations and mortality.Peer reviewe

    Defining Advance Care Planning for Adults: A Consensus Definition From a Multidisciplinary Delphi Panel

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    Despite increasing interest in advance care planning (ACP) and prior ACP descriptions, a consensus definition does not yet exist to guide clinical, research, and policy initiatives

    From causes to solutions - insights from lay knowledge about health inequalities

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    <p>Abstract</p> <p>Background</p> <p>This paper reports on a qualitative study of lay knowledge about health inequalities and solutions to address them. Social determinants of health are responsible for a large proportion of health inequalities (unequal levels of health status) and inequities (unfair access to health services and resources) within and between countries. Despite an expanding evidence base supporting action on social determinants, understanding of the impact of these determinants is not widespread and political will appears to be lacking. A small but growing body of research has explored how ordinary people theorise health inequalities and the implications for taking action. The findings are variable, however, in terms of an emphasis on structure versus individual agency and the relationship between being 'at risk' and acceptance of social/structural explanations.</p> <p>Methods</p> <p>This paper draws on findings from a qualitative study conducted in Adelaide, South Australia, to examine these questions. The study was an integral part of mixed-methods research on the links between urban location, social capital and health. It comprised 80 in-depth interviews with residents in four locations with contrasting socio-economic status. The respondents were asked about the cause of inequalities and actions that could be taken by governments to address them.</p> <p>Results</p> <p>Although generally willing to discuss health inequalities, many study participants tended to explain the latter in terms of individual behaviours and attitudes rather than social/structural conditions. Moreover, those who identified social/structural causes tended to emphasise individualized factors when describing typical pathways to health outcomes. This pattern appeared largely independent of participants' own experience of advantage or disadvantage, and was reinforced in discussion of strategies to address health inequalities.</p> <p>Conclusions</p> <p>Despite the explicit emphasis on social/structural issues expressed in the study focus and framing of the research questions, participants did not display a high level of knowledge about the nature and causes of place-based health inequalities. By extending the scope of lay theorizing to include a focus on solutions, this study offers additional insights for public health. Specifically it suggests that a popular constituency for action on the social determinants of health is unlikely to eventuate from the current popular understandings of possible policy levers.</p
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