| 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. |
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| 3. |
- Håkansson, Maria, et al.
(författare)
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Facilitating Mobile Music Sharing and Social Interaction with Push!Music
- 2007
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Ingår i: Proceedings of the 40th Hawaii International Conference on System Sciences. - Los Alamitos, Calif. : IEEE Computer Society Washington. - 1530-1605. - 0769527558 ; , s. 87-
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Konferensbidrag (refereegranskat)abstract
- Push!Music is a novel mobile music listening and sharing system, where users automatically receive songs that have autonomously recommended themselves from nearby players depending on similar listening behaviour and music history. Push!Music also enables users to wirelessly send songs between each other as personal recommendations. We conducted a two-week preliminary user study of Push!Music, where a group of five friends used the application in their everyday life. We learned for example that the shared music in Push!Music became a start for social interaction and that received songs in general were highly appreciated and could be looked upon as 'treats'.
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| 4. |
- Sunnerheim, Kerstin, et al.
(författare)
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Quantitative structure-activity relationships of pine weevil antifeedants, a Multivariate approach
- 2007
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 55:23, s. 9365-9372
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Tidskriftsartikel (refereegranskat)abstract
- Antifeedant activity of mainly phenylpropanoic, cinnamic, and benzoic acids esters was tested on the pine weevil, Hylobius abiefis (L.). Of 105 compounds screened for activity, 9 phenylpropanoates, 3 cinnamates, and 4 benzoates were found to be highly active antifeeclants. To understand the structure-activity relationships of these compounds, a multivariate analysis study was performed. A number of molecular and substituent descriptors were calculated and correlated to results from two-choice feeding tests with H. abietis. Three local models were developed that had good internal predictive ability. External test sets showed moderate predictivity. In general, low polarity, small size, and high lipophilicity were characteristics for compounds having good antifeeclant activity.
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| 7. |
- Lesch, Christine, et al.
(författare)
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A role for Hemolectin in coagulation and immunity in Drosophila melanogaster
- 2007
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Ingår i: Developmental and Comparative Immunology. - : Elsevier BV. - 0145-305X .- 1879-0089. ; 31:12, s. 1255-1263
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Tidskriftsartikel (refereegranskat)abstract
- Hemolectin has been identified as a candidate clotting factor in Drosophila. We reassessed the domain structure of Hemolectin (Hml) and propose that instead of C-type lectin domains, the two discoidin domains are most likely responsible for the protein's lectin activity. We also tested Hml's role in coagulation and immunity in Drosophila. Here we describe the isolation of a new hml allele in a forward screen for coagulation mutants, and our characterization of this and two other hml alleles, one of which is a functional null. While loss of Hml had strong effects on larval hemolymph coagulation ex vivo, mutant larvae survived wounding. Drosophila thus possesses redundant hemostatic mechanisms. We also found that loss of Hml in immune-handicapped adults rendered them more sensitive to Gram(-) bacteria infection. This demonstrates an immunological role of this clotting protein and reinforces the importance of the clot in insect immunity.
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| 8. |
- Ek, Helene, 1976, et al.
(författare)
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TNT leakage through sediment to water and toxicity to Nitocra spinipes
- 2007
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Ingår i: Ecotoxicology and Environmental Safety. - : Elsevier BV. - 0147-6513. ; 67:3, s. 341-348
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Tidskriftsartikel (refereegranskat)abstract
- The fate and effects of 2,4,6-trinitrotoluene (TNT) at marine ammunition dumping sites are essentially unknown. The objective of this study was to examine the release from solid TNT to seawater when covered by sediment of two different types (sandy and fine-grained) and thickness (0, 1, 2, and 4 cm), under different temperatures (5, 10, and 20 °C), and light conditions (ambient daylight and darkness) in the laboratory. The water column was analysed for TNT and some of its common transformation products, and toxicity to the copepod Nitocra spinipes after 1, 2, 4, 8, 19, and 32 weeks. Leakage of TNT to seawater and the toxicity to N. spinipes was significantly reduced by sediment burial, especially in fine-grained sediment. Hence, this study suggests that adverse effects of TNT in dumped ammunition on aquatic organisms should be delayed/reduced at low temperature and when TNT is covered sediment, especially with fine-grained sediment.
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| 9. |
- Gong, Jing, et al.
(författare)
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A stable and efficient hybrid scheme for viscous problems in complex geometries
- 2007
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Ingår i: Journal of Computational Physics. - Uppsala : Elsevier BV. - 0021-9991 .- 1090-2716. ; 226:2, s. 1291-1309
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present a stable hybrid scheme for viscous problems. The hybrid method combines the unstructured finite volume method with high-order finite difference methods on complex geometries. The coupling procedure between the two numerical methods is based on energy estimates and stable interface conditions are constructed. Numerical calculations show that the hybrid method is efficient and accurate.
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