| 1. |
- Berg, Björn, et al.
(författare)
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Decomposition rates in late stages of Scots pine and Norway spruce needle litter: Influence of nutrients and substrate properties over a climate gradient
- 2022
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Ingår i: Forest Ecology and Management. - : Elsevier. - 0378-1127 .- 1872-7042. ; 522
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this paper is to show different patterns for decomposition of the main mass of needle litter from two boreal and temperate coniferous tree species, both leading to a stabilized fraction of litter. To this purpose we have reviewed information on decomposition patterns in the lignin-dominated (late) stages of two local foliar litter types, namely those of Scots pine (Pinus silvestris) and Norway spruce (Picea abies) from two climatic gradients of equal extension. We have also reviewed factors determining the limit values for both species.Long-term decomposition studies were used to calculate annual mass loss in the lignin-dominated decomposition stage and relate these to mean annual temperature (MAT), mean annual precipitation (MAP) and concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn) and acid unhydrolyzable residue (gravimetric lignin, AUR).There was no effect of MAT on decomposition of either needle litter type. MAP had a rate-dampening effect on decomposition of Norway spruce litter. There was a rate-stimulating effect of Mn for Norway spruce litter but not for that of Scots pine. In spite of the strong negative effect of AUR and N on decomposition of Scots pine litter there was none at all for that of Norway spruce.Limit values for decomposition were related to the litters’ initial concentrations of N, Mn and AUR and differed between litter types for locally collected, natural litter and for that from experimental litter, the latter having higher N and lower Mn concentrations than the natural litter.We conclude that the two litter types have clear differences as regards rate- regulating factors for decomposition in the late lignin-dominated stage as well as for the stable fraction and suggest two different pathways for their decomposition. This is the first time that different pathways have been suggested for decomposing litter.
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| 2. |
- Berg, Björn, 1943-, et al.
(författare)
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Magnesium dynamics in decomposing foliar litter - a synthesis
- 2021
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Ingår i: Geoderma. - : Elsevier. - 0016-7061 .- 1872-6259. ; 382
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Tidskriftsartikel (refereegranskat)abstract
- We synthesized available data for magnesium (Mg) dynamics in newly shed and decomposing foliar litter of mainly pine (Pinus) species, Norway spruce (Picea abies), and birch (Betula) species. Using original, measured data from 40 stands organized in climatic gradients we intended to determine patterns of Mg concentration and net release vs accumulated mass loss of the litter. This synthesis is likely the first synthesis of Mg dynamics in decomposing litter.In paired stands, litter of both Norway spruce and lodgepole pine (Pinus contorta) had higher Mg concentrations than Scots pine (Pinus silvestris), with concentrations in Norway spruce litter even twice as high.In decomposing litter, Mg concentrations followed a quadratic (X2-X) function vs accumulated mass loss and consequently had minima, different for Norway spruce and Scots pine litter. Out of 68 decomposition studies 53 gave minimum concentration. The Mg minimum concentration during decomposition was positively related to initial Mg concentration for Scots pine and Scots pine plus lodgepole pine but not for Norway spruce. The increase in concentration suggests that after the minimum Mg was temporarily limiting.For Norway spruce litter there was a relationship between minimum concentration of Mg and the limit value. There was no such relationship for Scots pine and not for the combined pine data.Magnesium net release started directly after the incubation and was linear to accumulated mass loss of litter, giving a slope coefficient (release rate) for each study. The net release rate was linear to initial Mg concentration and all studies combined gave a negative linear relationship.
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| 3. |
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| 4. |
- Björling, Mikael, et al.
(författare)
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Air infiltration into naturally ventilated apartments in multifamily dwellings
- 2014
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Ingår i: Indoor Air 2014 - 13th International Conference on Indoor Air Quality and Climate. ; , s. 34-40
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Konferensbidrag (refereegranskat)abstract
- This study presents the ACH for ten apartments in naturally ventilated multifamily dwellings for two cases inlet vent manipulations: i) fully opened inlet vents; and ii) fully closed and taped inlet vents. Even with fully opened inlet vents the resulting ventilation is rather poor. The average ACH is 0.26±0.16 h-1. All apartments fall in the lower quartile in terms of ACH when compared to other multifamily dwellings in Sweden. A method using two different tracers A and B is presented that allow for measurement of the partial flow from the stairway zone and the partial flow from other pathways into the apartment. On the average 10-20% of the airflow into a typical apartment in a naturally ventilated multifamily dwelling seems to originate from the stairway zone when the inlet vents are fully opened. By closing and taping the inlet vents, the airtightness of the apartments have been investigated. The average direct leakage flow, i.e. not from the stairway zone, is 17 m3/h but the variation is large. Layout B seems to leak the most, followed by A and then C.
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| 5. |
- Elväng, Annelie, et al.
(författare)
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Sequencing of a Tick-Borne Encephalitis Virus from Ixodes ricinus Reveals a Thermosensitive RNA Switch Significant for Virus Propagation in Ectothermic Arthropods
- 2011
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Ingår i: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert Inc. - 1530-3667 .- 1557-7759. ; 11:6, s. 649-658
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Tidskriftsartikel (refereegranskat)abstract
- Tick-borne encephalitis virus (TBEV) is a flavivirus with major impact on global health. The geographical TBEV distribution is expanding, thus making it pivotal to further characterize the natural virus populations. In this study, we completed the earlier partial sequencing of a TBEV pulled out of a pool of RNA extracted from 115 ticks collected on Torö in the Stockholm archipelago. The total RNA was sufficient for all sequencing of a TBEV genome (Torö-2003), without conventional enrichment procedures such as cell culturing or suckling mice amplification. To our knowledge, this is the first time that the genome of TBEV has been sequenced directly from an arthropod reservoir. The Torö-2003 sequence has been characterized and compared with other TBE viruses. In silico analyses of secondary RNA structures formed by the two untranslated regions revealed a temperature-sensitive structural shift between a closed replicative form and an open AUG accessible form, analogous to a recently described bacterial thermoswitch. Additionally, novel phylogenetic conserved structures were identified in the variable part of the 3′-untranslated region, and their sequence and structure similarity when compared with earlier identified structures suggests an enhancing function on virus replication and translation. We propose that the thermo-switch mechanism may explain the low TBEV prevalence often observed in environmentally sampled ticks. Finally, we were able to detect variations that help in the understanding of virus adaptations to varied environmental temperatures and mammalian hosts through a comparative approach that compares RNA folding dynamics between strains with different mammalian cell passage histories.
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| 6. |
- Kristofferzon, Marja-Leena, 1950-, et al.
(författare)
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Evaluation of a Swedish version of the Watts Sexual Function Questionnaire (WSFQ) in persons with heart disease: A pilot study
- 2010
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Ingår i: European Journal of Cardiovascular Nursing. - Amsterdam : Elsevier. - 1474-5151 .- 1873-1953. ; 9:3, s. 168-174
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Tidskriftsartikel (refereegranskat)abstract
- Background: As part of preparation for a Swedish multicentre study, exploring sexual and married life in patients with myocardial infarction and their partners, a Swedish validated instrument was required. Aims:The aim of this pilot study was to evaluate the validity and reliability of a Swedish version of the Watts Sexual Function Questionnaire (WSFQ) among persons with a heart disease.Methods:A convenience sample of 79 persons (47 men and 32 women) living with a heart disease was recruited from the members of the National Association of Heart and Lung Patients. They completed a Swedish version of the WSFQ on two occasions. Results:Two separate factor analyses each revealed a two-factor structure on both occasions: “Sexual appetite” and “Sexual expectations ”with gender-neutral questions and “Sexual sensitiveness” and “Sexual ability” with gender-specific questions. Cronbach's alpha coefficients ranged from 0.48 to 0.86 and test – retest values for all but one question exceeded 0.70.Conclusions:The Swedish version of the WSFQ showed good validity and stability and acceptable internal homogeneity. Extended evaluations of the questionnaire are recommended.
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| 7. |
- Nyman, Teresia, et al.
(författare)
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Reliability and Validity of Six Selected Observational Methods for Risk Assessment of Hand Intensive and Repetitive Work
- 2023
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 20:8, s. 5505-
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Tidskriftsartikel (refereegranskat)abstract
- Risk assessments of hand-intensive and repetitive work are commonly done using observational methods, and it is important that the methods are reliable and valid. However, comparisons of the reliability and validity of methods are hampered by differences in studies, e.g., regarding the background and competence of the observers, the complexity of the observed work tasks and the statistical methodology. The purpose of the present study was to evaluate six risk assessment methods, concerning inter- and intra-observer reliability and concurrent validity, using the same methodological design and statistical parameters in the analyses. Twelve experienced ergonomists were recruited to perform risk assessments of ten video-recorded work tasks twice, and consensus assessments for the concurrent validity were carried out by three experts. All methods’ total-risk linearly weighted kappa values for inter-observer reliability (when all tasks were set to the same duration) were lower than 0.5 (0.15–0.45). Moreover, the concurrent validity values were in the same range with regards to total-risk linearly weighted kappa (0.31–0.54). Although these levels are often considered as being fair to substantial, they denote agreements lower than 50% when the expected agreement by chance has been compensated for. Hence, the risk of misclassification is substantial. The intra-observer reliability was only somewhat higher (0.16–0.58). Regarding the methods ART (Assessment of repetitive tasks of the upper limbs) and HARM (Hand Arm Risk Assessment Method), it is worth noting that the work task duration has a high impact in the risk level calculation, which needs to be taken into account in studies of reliability. This study indicates that when experienced ergonomists use systematic methods, the reliability is low. As seen in other studies, especially assessments of hand/wrist postures were difficult to rate. In light of these results, complementing observational risk assessments with technical methods should be considered, especially when evaluating the effects of ergonomic interventions.
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