| 1. |
- Galan, C., et al.
(författare)
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International observational campaigns of the last two eclipses in EE Cephei : 2003 and 2008/9
- 2012
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 544, s. A53-
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Tidskriftsartikel (refereegranskat)abstract
- Context. EECep is an unusual long-period (5.6 yr) eclipsing binary discovered during the mid-twentieth century. It undergoes almost-grey eclipses that vary in terms of both depth and duration at different epochs. The system consists of a Be type star and a dark dusty disk around an invisible companion. EECep together with the widely studied epsilon Aur are the only two known cases of long-period eclipsing binaries with a dark, dusty disk component responsible for periodic obscurations.Aims. Two observational campaigns were carried out during the eclipses of EECep in 2003 and 2008/9 to verify whether the eclipsing body in the system is indeed a dark disk and to understand the observed changes in the depths and durations of the eclipses.Methods. Multicolour photometric data and spectroscopic observations performed at both low and high resolutions were collected with several dozen instruments located in Europe and North America. We numerically modelled the variations in brightness and colour during the eclipses. We tested models with different disk structure, taking into consideration the inhomogeneous surface brightness of the Be star. We considered the possibility of disk precession.Results. The complete set of observational data collected during the last three eclipses are made available to the astronomical community. The 2003 and 2008/9 eclipses of EECep were very shallow. The latter is the shallowest among all observed. The very high quality photometric data illustrate in detail the colour evolution during the eclipses for the first time. Two blue maxima in the colour indices were detected during these two eclipses, one before and one after the photometric minimum. The first (stronger) blue maximum is simultaneous with a "bump" that is very clear in all the UBV(RI)(C) light curves. A temporary increase in the I-band brightness at the orbital phase similar to 0.2 was observed after each of the last three eclipses. Variations in the spectral line profiles seem to be recurrent during each cycle. The Na I lines always show at least three absorption components during the eclipse minimum and strong absorption is superimposed on the H alpha emission.Conclusions. These observations confirm that the eclipsing object in EECep system is indeed a dark, dusty disk around a low luminosity object. The primary appears to be a rapidly rotating Be star that is strongly darkened at the equator and brightened at the poles. Some of the conclusions of this work require verification in future studies: (i) a complex, possibly multi-ring structure of the disk in EECep; (ii) our explanation of the "bump" observed during the last two eclipses in terms of the different times of obscuration of the hot polar regions of the Be star by the disk; and (iii) our suggested period of the disk precession (similar to 11-12 P-orb) and predicted depth of about 2(m) for the forthcoming eclipse in 2014.
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| 2. |
- Kivimäki, M., et al.
(författare)
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Job strain as a risk factor for coronary heart disease : A collaborative meta-analysis of individual participant data
- 2012
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Ingår i: The Lancet. - : Elsevier. - 0140-6736 .- 1474-547X. ; 380:9852, s. 1491-1497
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Tidskriftsartikel (refereegranskat)abstract
- Background Published work assessing psychosocial stress (job strain) as a risk factor for coronary heart disease is inconsistent and subject to publication bias and reverse causation bias. We analysed the relation between job strain and coronary heart disease with a meta-analysis of published and unpublished studies. Methods We used individual records from 13 European cohort studies (1985-2006) of men and women without coronary heart disease who were employed at time of baseline assessment. We measured job strain with questions from validated job-content and demand-control questionnaires. We extracted data in two stages such that acquisition and harmonisation of job strain measure and covariables occurred before linkage to records for coronary heart disease. We defined incident coronary heart disease as the first non-fatal myocardial infarction or coronary death. Findings 30 214 (15%) of 197 473 participants reported job strain. In 1•49 million person-years at risk (mean follow-up 7•5 years [SD 1•7]), we recorded 2358 events of incident coronary heart disease. After adjustment for sex and age, the hazard ratio for job strain versus no job strain was 1•23 (95% CI 1•10-1•37). This effect estimate was higher in published (1•43, 1•15-1•77) than unpublished (1•16, 1•02-1•32) studies. Hazard ratios were likewise raised in analyses addressing reverse causality by exclusion of events of coronary heart disease that occurred in the first 3 years (1•31, 1•15-1•48) and 5 years (1•30, 1•13-1•50) of follow-up. We noted an association between job strain and coronary heart disease for sex, age groups, socioeconomic strata, and region, and after adjustments for socioeconomic status, and lifestyle and conventional risk factors. The population attributable risk for job strain was 3•4%. Interpretation Our findings suggest that prevention of workplace stress might decrease disease incidence; however, this strategy would have a much smaller effect than would tackling of standard risk factors, such as smoking. Funding Finnish Work Environment Fund, the Academy of Finland, the Swedish Research Council for Working Life and Social Research, the German Social Accident Insurance, the Danish National Research Centre for the Working Environment, the BUPA Foundation, the Ministry of Social Affairs and Employment, the Medical Research Council, the Wellcome Trust, and the US National Institutes of Health.
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| 3. |
- Theorell, Töres, et al.
(författare)
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Job strain in relation to body mass index : pooled analysis of 160 000 adults from 13 cohort studies
- 2012
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 272:1, s. 65-73
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Tidskriftsartikel (refereegranskat)abstract
- Job strain in relation to body mass index: pooled analysis of 160 000 adults from 13 cohort studies. J Intern Med 2012; 272: 6573. Background. Evidence of an association between job strain and obesity is inconsistent, mostly limited to small-scale studies, and does not distinguish between categories of underweight or obesity subclasses. Objectives. To examine the association between job strain and body mass index (BMI) in a large adult population. Methods. We performed a pooled cross-sectional analysis based on individual-level data from 13 European studies resulting in a total of 161 746 participants (49% men, mean age, 43.7 years). Longitudinal analysis with a median follow-up of 4 years was possible for four cohort studies (n = 42 222). Results. A total of 86 429 participants were of normal weight (BMI 18.524.9 kg m-2), 2149 were underweight (BMI < 18.5 kg m-2), 56 572 overweight (BMI 25.029.9 kg m-2) and 13 523 class I (BMI 3034.9 kg m-2) and 3073 classes II/III (BMI = 35 kg m-2) obese. In addition, 27 010 (17%) participants reported job strain. In cross-sectional analyses, we found increased odds of job strain amongst underweight [odds ratio 1.12, 95% confidence interval (CI) 1.001.25], obese class I (odds ratio 1.07, 95% CI 1.021.12) and obese classes II/III participants (odds ratio 1.14, 95% CI 1.011.28) as compared with participants of normal weight. In longitudinal analysis, both weight gain and weight loss were related to the onset of job strain during follow-up. Conclusions. In an analysis of European data, we found both weight gain and weight loss to be associated with the onset of job strain, consistent with a U-shaped cross-sectional association between job strain and BMI. These associations were relatively modest; therefore, it is unlikely that intervention to reduce job strain would be effective in combating obesity at a population level.
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| 4. |
- Heikkila, K., et al.
(författare)
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Job strain and the risk of severe asthma exacerbations : a meta-analysis of individual-participant data from 100 000 European men and women
- 2014
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Ingår i: Allergy. European Journal of Allergy and Clinical Immunology. - : Wiley. - 0105-4538 .- 1398-9995. ; 69:6, s. 775-783
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundMany patients and healthcare professionals believe that work-related psychosocial stress, such as job strain, can make asthma worse, but this is not corroborated by empirical evidence. We investigated the associations between job strain and the incidence of severe asthma exacerbations in working-age European men and women. MethodsWe analysed individual-level data, collected between 1985 and 2010, from 102 175 working-age men and women in 11 prospective European studies. Job strain (a combination of high demands and low control at work) was self-reported at baseline. Incident severe asthma exacerbations were ascertained from national hospitalization and death registries. Associations between job strain and asthma exacerbations were modelled using Cox regression and the study-specific findings combined using random-effects meta-analyses. ResultsDuring a median follow-up of 10years, 1 109 individuals experienced a severe asthma exacerbation (430 with asthma as the primary diagnostic code). In the age- and sex-adjusted analyses, job strain was associated with an increased risk of severe asthma exacerbations defined using the primary diagnostic code (hazard ratio, HR: 1.27, 95% confidence interval, CI: 1.00, 1.61). This association attenuated towards the null after adjustment for potential confounders (HR: 1.22, 95% CI: 0.96, 1.55). No association was observed in the analyses with asthma defined using any diagnostic code (HR: 1.01, 95% CI: 0.86, 1.19). ConclusionsOur findings suggest that job strain is probably not an important risk factor for severe asthma exacerbations leading to hospitalization or death.
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| 5. |
- Heikkilä, K., et al.
(författare)
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Job strain and health-related lifestyle : Findings from an individual-participant meta-analysis of 118 000 working adults
- 2013
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Ingår i: American Journal of Public Health. - 0090-0036 .- 1541-0048. ; 103:11, s. 2090-2097
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. We examined the associations of job strain, an indicator of work-related stress, with overall unhealthy and healthy lifestyles. Methods. We conducted a meta-analysis of individual-level data from 11 European studies (cross-sectional data: n = 118 701; longitudinal data: n = 43 971). We analyzed job strain as a set of binary (job strain vs no job strain) and categorical (high job strain, active job, passive job, and low job strain) variables. Factors used to define healthy and unhealthy lifestyles were body mass index, smoking, alcohol intake, and leisure-time physical activity. Results. Individuals with job strain were more likely than those with no job strain to have 4 unhealthy lifestyle factors (odds ratio [OR] = 1.25; 95% confidence interval [CI] = 1.12, 1.39) and less likely to have 4 healthy lifestyle factors (OR = 0.89; 95% CI = 0.80, 0.99). The odds of adopting a healthy lifestyle during study follow-up were lower among individuals with high job strain than among those with low job strain (OR = 0.88; 95% CI = 0.81, 0.96). Conclusions. Work-related stress is associated with unhealthy lifestyles and the absence of stress is associated with healthy lifestyles, but longitudinal analyses suggest no straightforward cause-effect relationship between workrelated stress and lifestyle. Copyright © 2013 by the American Public Health Association®.
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