| 1. |
- Cornelissen, Johannes H C, et al.
(författare)
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Global negative vegetation feedback to climate warming responses of leaf litter decomposition rates in cold biomes
- 2007
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 10:7, s. 619-627
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Tidskriftsartikel (refereegranskat)abstract
- Whether climate change will turn cold biomes from large long-term carbon sinks into sources is hotly debated because of the great potential for ecosystem-mediated feedbacks to global climate. Critical are the direction, magnitude and generality of climate responses of plant litter decomposition. Here, we present the first quantitative analysis of the major climate-change-related drivers of litter decomposition rates in cold northern biomes worldwide.Leaf litters collected from the predominant species in 33 global change manipulation experiments in circum-arctic-alpine ecosystems were incubated simultaneously in two contrasting arctic life zones. We demonstrate that longer-term, large-scale changes to leaf litter decomposition will be driven primarily by both direct warming effects and concomitant shifts in plant growth form composition, with a much smaller role for changes in litter quality within species. Specifically, the ongoing warming-induced expansion of shrubs with recalcitrant leaf litter across cold biomes would constitute a negative feedback to global warming. Depending on the strength of other (previously reported) positive feedbacks of shrub expansion on soil carbon turnover, this may partly counteract direct warming enhancement of litter decomposition.
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| 2. |
- Jägerbrand, Annika K, 1972-, et al.
(författare)
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Plant community responses to 5 years of simulated climate change in meadow and heath ecosystems at a subarctic-alpine site
- 2009
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 161:3, s. 601-610
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Tidskriftsartikel (refereegranskat)abstract
- Climate change was simulated by increasing temperature and nutrient availability in an alpine landscape. We conducted a field experiment of BACI-design (before/after control/impact) running for five seasons in two alpine communities (heath and meadow) with the factors temperature (increase of ca. 1.5-3.0°C) and nutrients (5 g N, 5 g P per m 2) in a fully factorial design in northern Swedish Lapland. The response variables were abundances of plant species and functional types. Plant community responses to the experimental perturbations were investigated, and the responses of plant functional types were examined in comparison to responses at the species level. Nutrient addition, exclusively and in combination with enhanced temperature increase, exerted the most pronounced responses at the species-specific and community levels. The main responses to nutrient addition were increases in graminoids and forbs, whereas deciduous shrubs, evergreen shrubs, bryophytes, and lichens decreased. The two plant communities of heath or meadow showed different vegetation responses to the environmental treatments despite the fact that both communities were located on the same subarctic-alpine site. Furthermore, we showed that the abundance of forbs increased in response to the combined treatment of temperature and nutrient addition in the meadow plant community. Within a single-plant functional type, most species responded similarly to the enhanced treatments although there were exceptions, particularly in the moss and lichen functional types. Plant community structure showed BACI responses in that vegetation dominance relationships in the existing plant functional types changed to varying degrees in all plots, including control plots. Betula nana and lichens increased in the temperature-increased enhancements and in control plots in the heath plant community during the treatment period. The increases in control plots were probably a response to the observed warming during the treatment period in the region. © Springer-Verlag 2009.
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| 3. |
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| 4. |
- Krüger, Niclas A, et al.
(författare)
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The Impact of Real Options on Willingness to Pay for Mortality Risk Reductions
- 2009
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Ingår i: Journal of Health Economics. - Amsterdam : ELSEVIER SCIENCE. - 0167-6296 .- 1879-1646. ; 28:3, s. 563-569
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Tidskriftsartikel (refereegranskat)abstract
- Public investments are dynamic in nature, and decision making must account for the uncertainty, irreversibility and potential for future learning. In this paper we adapt the theory for investment under uncertainty for a public referendum setting and perform the first empirical test to show that estimates of the value of a statistical lite (VSL) from stated preference surveys are highly dependent on the inclusion of the option value. Our results indicate an option value of a major economic magnitude. This implies that previously reported VSL estimates, used in societal benefit-cost analysis of health investments, are exaggerated.
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| 5. |
- Larsson, Helena, et al.
(författare)
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A Swedish survey of occupational therapists' involvement and performance in driving assessments
- 2007
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Ingår i: Scandinavian Journal of Occupational Therapy. - : Informa UK Limited. - 1103-8128 .- 1651-2014. ; 14:4, s. 215-220
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to examine the extent to which occupational therapists (OTs) are involved in driving assessments in Sweden and how these assessments are performed. A questionnaire was sent to 154 geriatric, rehabilitation, and neurological clinics, and additionally directly to 19 OTs who had purchased a test battery specifically used for driving assessments. The response rate was 60%. Of those responding, 57% reported being involved in fitness-to-drive assessments. However, such assessments were carried out in various manners and diverse methods were used, ranging from unstandardized activity assessments to a test developed specifically for driving assessments. Only 19% used on-road driving tests as a complement to the clinical assessments. Apart from the lack of appropriate methods, the respondents said that they did not have sufficient knowledge to perform driving assessments and expressed a need for further education. In the future it seems necessary for OTs in Sweden to undergo specialized training and perform the assessments on a regular basis to maintain a high level of competence as driving assessors.
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| 6. |
- Hjorth, Urban, 1941, et al.
(författare)
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Subsample distribution distance and McMC convergence
- 2005
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Ingår i: Scandinavian Journal of Statistics. - : Wiley. - 0303-6898 .- 1467-9469. ; 32:2, s. 313-326
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Tidskriftsartikel (refereegranskat)abstract
- A new measure based on comparison of empirical distributions for sub sequences or parallel runs and the full sequence of Markov chain Monte Carlo simulations, is proposed as a criterion of stability or convergence. The measure is also put forward as a loss function when the design of a Markov chain is optimized. The comparison is based on a Kullback-Leibler (KL) type distance over value sets defined by the output data. The leading term in a series expansion gives an interpretation in terms of the relative uncertainty of cell frequencies. The validity of this term is studied by simulation in two analytically tractable cases with Markov dependency. The agreement between the leading term and the KL-measure is close, in particular when the simulations are extensive enough for stable results. Comparisons with established criteria turn out favourably in examples studied.
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| 7. |
- Gidlöf-Gunnarsson, Anita, 1957, et al.
(författare)
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Good sound environment in green areas modify road-traffic noise annoyance at home
- 2009
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Ingår i: Proceedings of the 8th European Conference on Noise Control 2009 (EURONOISE 2009). - uo : Curran Associates, Inc.. ; , s. 1579-1587
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Konferensbidrag (populärvet., debatt m.m.)abstract
- There has been a growing recognition among noise researchers that natural elements and natural areas of the built environment have potentials to reduce annoyance due to traffic noise. It has been suggested that presence of vegetation (e.g., trees, bushes, grass, flowers) contributes to an aesthetically pleasing environment, which influence overall residential satisfaction and people?s perception of the noise. Other expected benefits of natural elements/areas are prevention or modification of adverse effects of work-, personal-, or environmental stress (e.g., noise) through restoration processes. Within the large TVANE-project, the present study examined the effect of green areas (park or similar at walking distance) on noise responses in residential settings (n=468) exposed to road traffic noise (LAeq,24h 45 to 65 dB). A binary multiple logistic regression analysis, with sound exposure as the prime variable assumed to predict general noise annoyance at home, indicated that presence of green areas, a closer distance to it from the subject?s home, and perceived green-area characteristics (good sound environment, high attractiveness and potentials for recreational activities) significantly lowered noise annoyance. The results suggest that the exposure-response relationship between noise and annoyance is influenced by access to nearby green areas provided that they have good environmental quality, particularly regarding the perceived sound environment
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| 8. |
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| 9. |
- Stave, Christina, et al.
(författare)
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An intervention method for occupational safety in farming : evaluation of the effect and process
- 2007
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Ingår i: Applied Ergonomics. - : Elsevier BV. - 0003-6870 .- 1872-9126. ; 38
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Tidskriftsartikel (refereegranskat)abstract
- In order to increase safety in Swedish farming an intervention methodology to influence attitudes and behaviour was tested. Eightyeight farmers and farm workers in nine groups gathered on seven occasions during 1 year. The basic concept was to create socially supportive networks and encourage discussions and reflection, focusing on risk manageability. Six of the groups made structured incident/accident analyses. Three of the latter groups also received information on risks and accident consequences. Effects were evaluated in a pre-post questionnaire using six-graded scales. A significant increase in safety activity and significant reduction in stress and risk acceptance was observed in the total sample. Risk perception and perceived risk manageability did not change. Analysing incidents/accidents, but not receiving information, showed a more positive outcome. Qualitative data indicated good feasibility and that the long duration of the intervention was perceived as necessary. The socially supportive network was reported as beneficial for the change process. © 2006 Elsevier Ltd. All rights reserved.
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| 10. |
- Stave, Christina, et al.
(författare)
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Risk and safety communication in small enterprises : how to support a lasting change towards work safety priority
- 2008
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Ingår i: Journal of Risk Research. - : Informa UK Limited. - 1366-9877 .- 1466-4461. ; 11:1, s. 195-206
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Tidskriftsartikel (refereegranskat)abstract
- The frequency of occupational accidents in Swedish farming is high. An intervention methodology aimed at influencing safety attitudes and behaviour was previously tested. The aims of the present study were to evaluate long‐term effects of the intervention and to assess these results in relation to a randomly selected comparison group.The intervention was based on regular group discussions, focusing on dialogue and reflection in networks for social support. Eighty‐eight farmers and farm workers, divided into nine groups, participated. Each group gathered on seven occasions during one year, assisted by a process consultant, supporting safety communication and the change process. A questionnaire was used to evaluate the effects. The long‐term results of the intervention showed that safety activity increased significantly and risk acceptance (fearlessness) and work stress decreased. Measurements were made at T1, T2 and T3, i.e., pre‐, post‐ and long‐term, in the intervention group and at T1 and T3 in the comparison group.The results of the present study showed a long‐term effect of the intervention on safety activity and risk acceptance (fearlessness) in relation to the comparison group. However, the comparison group also showed a decline in work stress, which indicates that the stress reduction may have had other causes than the intervention.
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