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- Aldahan, Ala, et al.
(författare)
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Atmospheric impact on beryllium isotopes as solar activity proxy
- 2008
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 35:L21812
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Tidskriftsartikel (refereegranskat)abstract
- Reconstructing solar activity variability beyond the time scale of actual measurements provides invaluable data for modeling of past and future climate change. The 10 Be isotope has been a primary proxy archive of past solar activity and cosmic ray intensity, particularly for the last millennium. There is, however, a lack of direct high-resolution atmospheric time series on 10 Be that enable estimating atmospheric modulation on the production signal. Here we report quasi-weekly data on 10 Be and 7 Be isotopes covering the periods 1983-2000 and 1975-2006 respectively, that show, for the first time, coherent variations reflecting both atmospheric and production effects. Our data indicate intrusion of stratosphere/upper troposphere air masses that can modulate the isotopes production signal, and may induce relative peaks in the natural 10 Be archives (i.e., ice and sediment). The atmospheric impact on the Be-isotopes can disturb the production signals and consequently the estimate of past solar activity magnitude. Citation: Aldahan, A., J. Hedfors, G. Possnert, A. Kulan, A.-M. Berggren, and C. Soderstrom (2008), Atmospheric impact on beryllium isotopes as solar activity proxy, Geophys. Res. Lett., 35, L21812, doi: 10.1029/2008GL035189.
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| 4. |
- Ekstedt, Mirjam, et al.
(författare)
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Disturbed sleep and fatigue in occupational burnout
- 2006
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Ingår i: Scandinavian Journal of Work, Environment and Health. - : Scandinavian Journal of Work, Environment and Health. - 0355-3140 .- 1795-990X. ; 32:2, s. 121-31
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The purpose of this study was to investigate sleep with polysomnography and self-ratings and the diurnal pattern of sleepiness and fatigue in a group suffering from severe occupational burnout.METHOD: Twelve white-collar workers on long-term sick leave (>3 months) and 12 healthy controls with high and low scores on the Shirom Melamed Burnout Questionnaire (SMBQ) were included. A 1-night polysomnographic recording (after habituation) was carried out at home, and sleepiness and mental fatigue were rated at different times of the day for weekdays and the weekend. Precipitating factors at the time of the illness at work and real life were considered, and different dimensions of occupational fatigue were described. A repeated-measures analysis of variance using two or three within group factors was used to analyze the data.RESULTS: The main polysomnographic findings were more arousals and sleep fragmentation, more wake time and stage-1 sleep, lower sleep efficiency, less slow wave sleep and rapid eye movement sleep, and a lower delta power density in non-rapid eye movement sleep in the burnout group. The burnout patients showed pronounced sleepiness and mental fatigue at most times of the day for weekdays without reduction during weekends. The precipitating factor was occupational stress (psychiatric interview), and work stress indicators were increased.CONCLUSIONS: Occupational burnout is characterized by impaired sleep. It is suggested that impaired sleep may play a role in the development of fatigue or exhaustion in burnout.
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| 5. |
- Ekstedt, Mirjam, et al.
(författare)
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Sleep physiology in recovery from burnout
- 2009
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Ingår i: Biological Psychology. - : Elsevier BV. - 0301-0511 .- 1873-6246. ; 82:3, s. 267-73
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to investigate the role of sleep physiology in recovery from burnout, in particular the relation between sleep and changes in fatigue and whether those changes would be related to return to work. 23 white-collar workers on long-term sick leave (>3 months) due to a burnout related diagnosis and 16 healthy controls were subjected to polysomnographic recordings at baseline and after 6-12 months' rehabilitation. Occupational status, subjective sleep quality, fatigue, anxiety and depression were assessed. Recovery from burnout was accompanied by improved sleep continuity. Significant interaction effects were seen for number of arousals, sleep fragmentation, sleep latency, sleep efficiency and time of rising. The burnout group improved significantly on all symptom variables although the post-treatment levels did not reach the levels of the controls. Recovery from fatigue was related to a reduction of the arousal from sleep and was the best predictor of return to work.
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| 6. |
- Ingre, Michael, et al.
(författare)
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Sleep length as a function of morning shift-start time in irregular shift schedules for train drivers : self-rated health and individual differences.
- 2008
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Ingår i: Chronobiol Int. - : Informa UK Limited. - 1525-6073 .- 0742-0528. ; 25:2, s. 349-58
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Tidskriftsartikel (refereegranskat)abstract
- Sleep length as a function of morning shift-start time in irregular shift schedules for train drivers: self-rated health and individual differences.Ingre M, Kecklund G, Akerstedt T, Söderström M, Kecklund L.Stress Research Institute, Stockholm University, Sweden. michael.ingre@stressforskning.su.seForty-six male train drivers (mean age = 46.5, SD = 5.1) were recruited to participate in a diary study for 14 consecutive days with questions about their sleep and working hours. A polynomial mixed-effect regression model showed a curvilinear relation ( p < .001) between shift-start time and sleep duration for shifts starting at 03:00-12:00 hand with a near linear increase for ones starting between 04:30 and 09:00 h of approximately 0.7 h for every 1 h the shift was delayed. The longest sleeps were estimated at approximately 8 h before shifts that started at approximately 10:00 h. The shortest sleeps were found for shifts that started before 04:30 h and were estimated at approximately 5 h. Individual differences were estimated with a random-effect standard deviation of 0.51 h, independent of shift start time ( p = .005). One-half of the between-subject variance was explained by subjective health. A one-step decrease in health was associated with a 26 min increase in sleep length. The results have practical implications for constructing shift schedules. Early morning shifts reduced sleep length substantially and should be mixed with later start hours to avoid the accumulation of sleep dept. Delaying the shift-start past 10:00 h had little effect on sleep opportunity; however, delaying shift-start to between 04:30 and 9:00 h had a strong impact on sleep length, with 70% of the extra time used for sleep, suggesting large positive effects for this range of shift-start times.
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| 8. |
- Söderström, Ann, 1961, et al.
(författare)
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Predictive factors and virological response to interferon treatment in children with chronic hepatitis B.
- 2005
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Ingår i: Scandinavian journal of infectious diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 37:1, s. 40-7
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Tidskriftsartikel (refereegranskat)abstract
- Further knowledge about factors predicting response to interferon treatment for chronic hepatitis B in children is required, in particular as the benefits of therapy are uncertain. In the present study, baseline characteristics were related to virological and histological responses in 27 children given interferon-alpha for 24 weeks after steroid priming. HBe seroconversion was seen in 8 of 27 HBeAg positive patients and was accompanied by a sustained virological response (SR), with a median 4.1 log HBV DNA reduction. Pretreatment viraemia level was the only baseline parameter associated with SR. After 12 weeks of IFN (mid-treatment), viraemia was significantly reduced in all patients, with a median of 3.0 (range 0.6-5.2) log decline in SR compared with 0.6 (range -0.5-3.6) log decline in non-sustained responders (NSR). HBV DNA levels below 1 million copies/ml at week 12 predicted sustained response with a positive predictive value of 75% and a negative predictive value of 89%. During the latter half of the IFN treatment HBV DNA tended to increase by a mean of 0.4-0.5 log for all patient groups. Flares during IFN treatment were rare or mild as measured by ALT. Pretreatment anti-HBc IgM was associated with liver damage but not with response. Histological inflammation scores were improved in SR. Thus, pretreatment HBV DNA levels were associated with IFN response, and the virological response at week 12 predicts SR and may be useful in the decision to continue or modify therapy.
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| 10. |
- Söderström, Ing-Marie, et al.
(författare)
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Interactions between family members and staff in intensive care units-An observation and interview study.
- 2006
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Ingår i: International Journal of Nursing Studies. - : Elsevier BV. - 1873-491X .- 0020-7489. ; 43:6, s. 707-716
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Tidskriftsartikel (refereegranskat)abstract
- Background: Research about interactions between family members and staff are sparse, although family members’ needs and experiences in intensive care units are well researched areas. Aim: The aim was to describe and interpret interactions between family members and staff in intensive care units. Methods: Interviews (n=24) with family members and repeated observations of interactions of family members and staff in intensive care units were performed and analysed together by means of content analysis. Results: The initial interactions between staff and family members had a substantial effect on family members and influenced their further interactions with the staff. Two kinds of interactions were revealed; mutual understanding and mutual misunderstanding. Family members, who understood the explicit information and the implicit messages were open in communication with the staff, adjusted well to the system, were acknowledged by the staff and sometimes consoled. Family members, who had difficulties understanding information and implicit messages drew back from communication with staff, did not adjust to the system and were sometimes insulted by the staff. Conclusions: Unambiguous information from the staff is important for developing interactions of mutual understanding. The results may be a starting point for intensive care unit staff to reflect on how all family members are initially met and further informed and treated. Further research of family members’ experiences of interactions with staff in a longitudinal perspective and the influence of critical illness on families are needed.
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