1,006 research outputs found

    Gamma-ray bursts and terrestrial planetary atmospheres

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    We describe results of modeling the effects on Earth-like planets of long-duration gamma-ray bursts (GRBs) within a few kiloparsecs. A primary effect is generation of nitrogen oxide compounds which deplete ozone. Ozone depletion leads to an increase in solar UVB radiation at the surface, enhancing DNA damage, particularly in marine microorganisms such as phytoplankton. In addition, we expect increased atmospheric opacity due to buildup of nitrogen dioxide produced by the burst and enhanced precipitation of nitric acid. We review here previous work on this subject and discuss recent developments, including further discussion of our estimates of the rates of impacting GRBs and the possible role of short-duration bursts.Comment: 12 pages including 5 figures (4 in color). Added discussion of GRB rates and biological effects. Accepted for publication in New Journal of Physics, for special issue "Focus on Gamma-Ray Bursts

    ‘He's a Cracking Wee Geezer from Pakistan’: Lay Accounts of Refugee Integration Failure and Success in Scotland

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    Previous research on the integration of asylum seekers and refugees has aimed to develop conceptual frameworks for understanding integration or to measure the extent to which people are integrated. However, this research tends to pay insufficient attention to the rhetorical functions of integration discourse. The current study addresses this gap through a discursive analysis of ‘lay’ accounts of asylum seeker and refugee integration in Glasgow, Scotland. The analysis highlights that accounts of integration ‘failure’ may support ‘two-way’ conceptions of integration while still blaming asylum seekers for any lack of integration. Furthermore, accounts of integration ‘success’ may reinforce assimilationist policies or otherwise function to reinforce the view that adult asylum seekers generally do not integrate. The analysis highlights the importance of attending to the rhetorical functions of integration discourse in order to understand how particular policies and practices are supported or criticised at the community level at which integration takes place

    Sources of Variation in Physician Adherence with Clinical Guidelines: Results from a Factorial Experiment

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    BACKGROUND: Health services research has documented the magnitude of health care variations. Few studies focus on provider level sources of variation in clinical decision making-for example, which primary care providers are likely to follow clinical guidelines, with which types of patient. OBJECTIVES: To estimate: (1) the extent of primary care provider adherence to practice guidelines and the unconfounded influence of (2) patient attributes and (3) physician characteristics on adherence with clinical practice guidelines. DESIGN: In a factorial experiment, primary care providers were shown clinically authentic video vignettes with actors portrayed different “patients” with identical signs of coronary heart disease (CHD). Different types of providers were asked how they would manage the different “patients” with identical CHD symptoms. Measures were taken to protect external validity. RESULTS: Adherence to some guidelines is high (over 50% of physicians would follow a third of the recommended actions), yet there is low adherence to many of them (less than 20% would follow another third). Female patients are less likely than males to receive 4 of 5 types of physical examination (p < .03); older patients are less likely to be advised to stop smoking (p < .03). Race and SES of patients had no effect on provider adherence to guidelines. A physicians’ level of experience (age) appears to be important with certain patients. CONCLUSIONS: Physician adherence with guidelines varies with different types of “patient” and with the length of clinical experience. With this evidence it is possible to appropriately target interventions to reduce health care variations by improving physician adherence with clinical guidelines

    Bibliometrics of systematic reviews : analysis of citation rates and journal impact factors

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    Background: Systematic reviews are important for informing clinical practice and health policy. The aim of this study was to examine the bibliometrics of systematic reviews and to determine the amount of variance in citations predicted by the journal impact factor (JIF) alone and combined with several other characteristics. Methods: We conducted a bibliometric analysis of 1,261 systematic reviews published in 2008 and the citations to them in the Scopus database from 2008 to June 2012. Potential predictors of the citation impact of the reviews were examined using descriptive, univariate and multiple regression analysis. Results: The mean number of citations per review over four years was 26.5 (SD +/-29.9) or 6.6 citations per review per year. The mean JIF of the journals in which the reviews were published was 4.3 (SD +/-4.2). We found that 17% of the reviews accounted for 50% of the total citations and 1.6% of the reviews were not cited. The number of authors was correlated with the number of citations (r = 0.215, P =5.16) received citations in the bottom quartile (eight or fewer), whereas 9% of reviews published in the lowest JIF quartile (<=2.06) received citations in the top quartile (34 or more). Six percent of reviews in journals with no JIF were also in the first quartile of citations. Conclusions: The JIF predicted over half of the variation in citations to the systematic reviews. However, the distribution of citations was markedly skewed. Some reviews in journals with low JIFs were well-cited and others in higher JIF journals received relatively few citations; hence the JIF did not accurately represent the number of citations to individual systematic reviews

    Population health and the economy: Mortality and the Great Recession in Europe

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    We analyze the evolution of mortality‐based health indicators in 27 European countries before and after the start of the Great Recession. We find that in the countries where the crisis has been particularly severe, mortality reductions in 2007–2010 were considerably bigger than in 2004–2007. Panel models adjusted for space‐invariant and time‐invariant factors show that an increase of 1 percentage point in the national unemployment rate is associated with a reduction of 0.5% (p < .001) in the rate of age‐adjusted mortality. The pattern of mortality oscillating procyclically is found for total and sex‐specific mortality, cause‐specific mortality due to major causes of death, and mortality for ages 30–44 and 75 and over, but not for ages 0–14. Suicides appear increasing when the economy decelerates—countercyclically—but the evidence is weak. Results are robust to using different weights in the regression, applying nonlinear methods for detrending, expanding the sample, and using as business cycle indicator gross domestic product per capita or employment‐to‐population ratios rather than the unemployment rate. We conclude that in the European experience of the past 20 years, recessions, on average, have beneficial short‐term effects on mortality of the adult population.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142224/1/hec3495_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142224/2/hec3495.pd

    Women, men and coronary heart disease: a review of the qualitative literature

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    Aim. This paper presents a review of the qualitative literature which examines the experiences of patients with coronary heart disease. The paper also assesses whether the experiences of both female and male patients are reflected in the literature and summarizes key themes. Background. Understanding patients' experiences of their illness is important for coronary heart disease prevention and education. Qualitative methods are particularly suited to eliciting patients' detailed understandings and perceptions of illness. As much previous research has been 'gender neutral', this review pays particular attention to gender. Methods. Published papers from 60 qualitative studies were identified for the review through searches in MEDLINE, EMBASE, CINAHL, PREMEDLINE, PsychINFO, Social Sciences Citation Index and Web of Science using keywords related to coronary heart disease. Findings. Early qualitative studies of patients with coronary heart disease were conducted almost exclusively with men, and tended to generalize from 'male' experience to 'human' experience. By the late 1990s this pattern had changed, with the majority of studies including women and many being conducted with solely female samples. However, many studies that include both male and female coronary heart disease patients still do not have a specific gender focus. Key themes in the literature include interpreting symptoms and seeking help, belief about coronary 'candidates' and relationships with health professionals. The influence of social roles is important: many female patients have difficulties reconciling family responsibilities and medical advice, while male patients worry about being absent from work. Conclusions. There is a need for studies that compare the experiences of men and women. There is also an urgent need for work that takes masculinity and gender roles into account when exploring the experiences of men with coronary heart disease

    Impact of Spironolactone on Longitudinal Changes in Health-Related Quality of Life in the Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist Trial

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    BACKGROUND: Heart failure (HF) with preserved ejection fraction patients have equally impaired health-related quality of life (HRQL) compared with those with HF with reduced ejection fraction, but limited studies have evaluated the impact of therapies on changes in HRQL. METHODS AND RESULTS: Patients ≥50 years of age, with symptomatic HF and left ventricular ejection fraction ≥45%, were enrolled in Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist (TOPCAT) and randomized to spironolactone or placebo. Patients completed the Kansas City Cardiomyopathy Questionnaire (KCCQ), which was the primary HRQL instrument, and EQ5D visual analog scale at baseline, 4 months, 12 months, and annually thereafter. McMaster Overall Treatment Evaluation was assessed at 4 and 12 months to assess global change scores. Change scores (+SD) were calculated to determine between-group differences, and multivariable repeated-measures models were created to identify other factors associated with change scores. Paired KCCQ data were available for 91.7% of 3445 TOPCAT patients. By 4 months, the mean change in KCCQ was 7.7±16 and mean change in EQ5D visual analog scale was 4.7±16. Adjusted mean changes in KCCQ for the spironolactone group were significantly better than those for the placebo group at 4-month (1.54 better; P=0.002), 12-month (1.35 better; P=0.02), and 36-month (1.86 better; P=0.02) visits. No between-group differences in EQ5D visual analog scale change scores or McMaster Overall Treatment Evaluation were noted. Older age, obesity, current smoking, New York Heart Association class III/IV, and comorbid illnesses were associated with declines in KCCQ scores. Use of spironolactone was an independent predictor of improved KCCQ scores. CONCLUSIONS: In symptomatic HF with preserved ejection fraction patients, use of spironolactone was associated with an improvement in HF-specific HRQL. Several modifiable risk factors were associated with HRQL deterioration. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00094302

    Role Stress, Role Reward, and Mental Health in a Multiethnic Sample of Midlife Women: Results from the Study of Women's Health Across the Nation (SWAN)

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    Abstract Background: Little is known about the independent associations of reward and stress within specific roles with multiple measures of mental health in an ethnically diverse community sample of midlife women. The objective of this study is to examine if (1) role reward (within each role and across roles) contributes directly to mental health and buffers the negative impact of role stress and (2) associations among role occupancy, role stress, and role reward and mental health vary by race/ethnicity. Methods: With separate logistic regression analysis, we investigated cross-sectional relationships between role stress and role reward with presence/absence of high depressive symptoms (Center for Epidemiologic Studies Depression Scale [CES-D≥16]), anxiety symptoms (feeling tense or nervous, irritable or grouchy, fearful for no reason, and heart pounding or racing total score≥4), or low social functioning (bottom 25th percentile of the Short-Form-36 [SF-36] social functioning subscale) in 2549 women participating in the third visit of the Study of Women's Health Across the Nation (SWAN), a longitudinal population-based study of menopause. Results: High reward across roles attenuated the negative impact of role stress on social functioning but not on anxiety or depression. High reward marriage buffered the impact of marital stress on depression, and high reward mothering buffered the effect of maternal stress on depression and social functioning. Compared to Caucasians, Hispanics and Chinese with high stress across roles had better social functioning, and African American mothers had lower odds of high depressive symptoms. Conclusions: Role reward buffers the negative impact of stress on social functioning and depression, but not on anxiety. Minorities may respond to role stress by seeking social support.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98462/1/jwh%2E2011%2E3180.pd

    Spironolactone in Patients With Heart Failure, Preserved Ejection Fraction, and Worsening Renal Function

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    BACKGROUND Treatment of heart failure with preserved ejection fraction (HFpEF) with spironolactone is associated with lower risk of heart failure hospitalization (HFH) but increased risk of worsening renal function (WRF). The prognostic implications of spironolactone-associated WRF in HFpEF patients are not well understood. OBJECTIVES The purpose of this study was to investigate the association between WRF, spironolactone treatment, and clinical outcomes in patients with HFpEF. METHODS In 1,767 patients randomized to spironolactone or placebo in the TOPCAT (Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist Trial)-Americas study, we examined the incidence of WRF (doubling of serum creatinine) by treatment assignment. Associations between incident WRF and subsequent risk for the primary study endpoint of cardiovascular (CV) death, HFH, or aborted cardiac arrest and key secondary outcomes, including CV death, HFH, and all-cause mortality according to treatment assignment, were examined in time-updated Cox proportional hazards models with an interaction term. RESULTS WRF developed in 260 (14.7%) patients with higher rates in those assigned to spironolactone compared to placebo (17.8% vs. 11.6%; odds ratio: 1.66; 95% confidence interval: 1.27 to 2.17; p < 0.001). Regardless of treatment, incident WRF was associated with increased risk for the primary endpoint (hazard ratio: 2.04; 95% confidence interval: 1.52 to 2.72; p < 0.001) after multivariable adjustment. Although there was no statistical interaction between treatment assignment and WRF regarding the primary endpoint (interaction p = 0.11), spironolactone-associated WRF was associated with lower risk of CV death (interaction p = 0.003) and all-cause mortality (interaction p = 0.001) compared with placebo-associated WRF. CONCLUSIONS Among HFpEF patients enrolled in TOPCAT-Americas, spironolactone increased risk of WRF compared with placebo. Rates of CV death were lower with spironolactone in both patients with and without WRF. (c) 2021 the American College of Cardiology Foundation. Published by Elsevier. All rights reserved
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