| 1. |
- Malmström, Anna, et al.
(författare)
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Dynamics of soil meso- and macrofauna during a 5-year period after clear-cut burning in a boreal forest
- 2009
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Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 43, s. 61-74
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to determine effects of clear-cutting and prescribed clear-cut burning on the abundance and diversity of soil meso- and macrofauna during the early (0-5 years) recovery/recolonisation phase. A 115-year-old stand of mixed Pinus sylvestris and Picea abies in central Sweden was clear-cut in March 1999. Injune 1999, two plots on the clear-cut were burnt and two plots were left unburnt according to an experimental design with two blocks. Two plots of adjacent uncut forest were used as controls. The burning combusted the ground vegetation and the upper half of the 6-cm thick organic layer. In comparison with the unburnt clear-cut, burning decreased the abundances of Collembola, Protura, Mesostigmata, Araneae and Diptera larvae throughout the 5-year period, whereas Enchytraeidae, Lumbricidae, Oribatida, Prostigmata, Astigmata and Tardigrada decreased immediately after the fire but showed tendencies of recovery. Burning also decreased species richness. The majority of the species still absent after 5 years was surface-living species. Even animals with good ability to disperse (Diptera, Coleoptera and Araneae) had not recovered, which indicates a change of habitat or lack of food. Clear-cut burning was particularly detrimental to fungivores and predators, whereas microbidetritivores and herbivores were less affected. Prescribed burning, which is considered to increase aboveground biodiversity, dramatically reduced the soil fauna species richness for at least 5 years and did not add any species to those already present in the forest or clear-cut. (C) 2009 Elsevier B.V. All rights reserved.
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| 2. |
- Ahlin, Åsa, et al.
(författare)
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Effects of decentralization on school resources
- 2008
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Ingår i: Economics of Education Review. - : Elsevier BV. - 0272-7757 .- 1873-7382. ; 27:3, s. 276-284
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Tidskriftsartikel (refereegranskat)abstract
- Sweden has undertaken major national reforms of its school sector, which, consequently, has been classified as one of the most decentralized ones in the OECD. This paper investigates whether local tax base, grants, and preferences affected local school resources differently as decentralization took place. We find that municipal tax base affects per pupil spending in the same way regardless of whether the school sector is centralized or decentralized, but has a smaller effect on teacher–pupil ratio after the reforms. The less-targeted grants are the fewer teachers per pupil do the municipalities employ. The results for local preferences are less clear-cut.
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| 3. |
- Aldén, Louise, et al.
(författare)
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The use of leucine incorporation to determine the toxicity of phenols to bacterial communities extracted from soil
- 2008
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Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 38:1, s. 34-41
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Tidskriftsartikel (refereegranskat)abstract
- The toxicity of different phenols to the soil bacterial community was studied in the laboratory using the leucine incorporation technique. The effects of environmental factors such as pH, temperature and binding strength to soil particles were also assessed in order to deduce confounding effects due to the chemical and physical conditions in the soil from which the bacterial community was extracted. Bacterial growth varied with temperature and pH, the optima being at around 33 degrees C and pH 7 in a soil with a natural pH of 7. The toxicity of different phenols varied less than bacterial growth as a function of temperature and pH, but the toxicity of 2,3,6-trichlorophenol increased at lower temperatures and pH. The pH affected the toxicity in the same way in soils with naturally different pH values and when the pH was changed using buffers, showing that this was a direct effect of pH and was not due to different communities in different soils. The degree to which the bacteria were bound to soil particles had no effect on the toxicity of phenols. Neither did freezing nor thawing the soil have any effect on toxicity, although the bacterial growth was lower in frozen soil than in non-frozen soil. Increasing numbers of substitutes on the phenols increased their toxicity to soil bacteria, and chlorine substitutes were more toxic than the corresponding methyl substitutes. The toxicity of the phenols studied to the whole soil bacterial community was correlated with literature data on the toxicity to the single species Pseudomonas putida. Applying the leucine incorporation technique to the bacterial community extracted from soil was shown to be a rapid and sensitive method of estimating toxicity. The methodology also allowed differentiation between the effects of environmental factors on toxicity to the soil bacterial community and changes in the tolerance of the community. Thus, the development of pollution-induced community tolerance in phenol- and 2-chlorophenol-polluted soils could be shown. (c) 2007 Elsevier B.V. All rights reserved.
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| 4. |
- Bracht Jørgensen, Helene, et al.
(författare)
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Life-history traits of soil collembolans in relation to food quality
- 2008
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Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 38:2, s. 146-151
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Tidskriftsartikel (refereegranskat)abstract
- Preference studies of many different collembolan species have categorised collembolans being selective in their food choice. To clarify whether collembolan food selectivity is related to fitness parameters, three species, Folsomia fimetaria, Protaphorura armata and Heteromurus nitidus, were fed three fungal species, Alternaria infectoria, Mucor hiemalis and Penicillium hordei, representing fungi of high, medium and low preference. The fungal diets were grown on soil and collembolan growth, survival and fecundity were measured. The fungus A. infectoria supported growth, survival and reproduction best in all three species of collembolans, while the fungus P. hordei was of low food quality. M. hiemalis was of medium quality and F. fimetaria was the only collembolan reproducing on M. hiemalis. F. fimetaria favoured reproduction over growth when confined to M. hiemalis. When P. armata was fed M. hiemalis it reached a size where reproduction normally starts, but no young were produced. This suggests that M. hiemalis lacks nutrients necessary for reproduction. H. nitidus did not perform well on any of the fungi offered, which were generally of low food quality for this species. In this study, where the fungal growth substrate is soil, there is a clear relationship between collembolan fitness and their food choice in contrast to some other studies where substrates optimised for fungal growth had been used. We show that specific fungal species are important for resource allocation to growth or reproduction and closely connected with food choice. Further, we argue that natural fungal growth substrates, such as soil, should be used in experiments of this kind.
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| 5. |
- Dahl, P., et al.
(författare)
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Densification and properties of zirconia prepared by three different sintering techniques
- 2007
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Ingår i: Ceramics International. - : Elsevier BV. - 0272-8842 .- 1873-3956. ; 33:8, s. 1603-1610
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Tidskriftsartikel (refereegranskat)abstract
- Densification of nanocrystalline yttria stabilized zirconia (YSZ) powder with 8 mol% Y2O3, prepared by a glycine/nitrate smoldering combustion method, was investigated by spark plasma sintering, hot pressing and conventional sintering. The spark plasma sintering technique was shown to be superior to the other methods giving dense materials (>= 96%) with uniform morphology at lower temperatures and shorter sintering time. The grain size of the materials was 0.21, 0.37 and 12 mu m after spark plasma sintering, hot pressing and conventional sintering, respectively. Total electrical conductivity of the materials showed no clear correlation with the grain size, but the activation energy for spark plasma sintered materials was slightly higher than for materials prepared by the two other densification methods. The hardness, measured by the Vickers indentation method, was found to be independent on grain size while fracture toughness, derived by the indentation method, was slightly decreasing with increasing grain size.
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| 6. |
- Elfstrand, S, et al.
(författare)
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Soil enzyme activities, microbial community composition and function after 47 years of continuous green manuring
- 2007
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Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 35:3, s. 610-621
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Tidskriftsartikel (refereegranskat)abstract
- Green manuring practices can influence soil microbial community composition and function and there is a need to investigate the influence compared with other types of organic amendment. This study reports long-term effects of green manure amendments on soil microbial properties, based on a field experiment started in 1956. In the experiment, various organic amendments, including green manure, have been applied at a rate of 4 t C ha(-1) every second year. Phospholipid fatty acid analysis (PLFA) indicated that the biomass of bacteria, fungi and total microbial biomass, but not arbuscular mycorrhizal (AM) fungi, generally increased due to green manuring compared with soils receiving no organic amendments. Some differences in abundance of different microbial groups were also found compared with other organic amendments (farmyard manure and sawdust) such as a higher fungal biomass and consequently a higher fungal/bacterial ratio compared with amendment with farmyard manure. The microbial community composition (PLFA profile) in the green manure treatment differed from the other treatments, but there was no effect on microbial substrate-utilization potential, determined using the Biolog EcoPlate. Protease and arylsulphatase activities in the green manure treatment were comparable to a mineral fertilized treatment receiving no additional C, whereas acid phosphatase activity increased. It can be concluded that green manuring had a beneficial impact on soil microbial properties, but differed in some aspects to other organic amendments which might be attributed to differences in quality of the amendments.
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| 7. |
- Gavito, Mayra, et al.
(författare)
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Foraging strategies of the external mycelium of the arbuscular mycorrhizal fungi Glomus intraradices and Scutellospora calospora
- 2008
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Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 39:3, s. 282-290
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Tidskriftsartikel (refereegranskat)abstract
- The responsiveness of the external mycelium of Glomus intraradices and Scutellospora calospora was tested in a multiple-choice experimental system in which mycelium encountered patches amended with nitrogen (N) or phosphorus (P), either alone or in combination with a host plant. We hypothesised that only AMF mycelium with sufficient supply of photo-synthate from an actively growing host would respond to the amendments provided. Mycelium was allowed to grow either 11 or 21 weeks before we analysed hyphal proliferation in amended patches introduced in mesh bags that were not reached by roots but by foraging mycelium only. Hyphal length, the AMF signature fatty acid 16:1w5, and root colonisation in new host plant seedlings were used to measure AMF growth and resource allocation in the patches. Mycelium from both fungal strains was able to colonise new host roots and sand in all patches but S. calospora was overall more responsive to the amendments than G. intraradices. G. intraradices grew equally into all patches, including the unamended control, whereas S. calospora produced significantly more hyphal length in the patch containing a host plant than in the rest of the patches. Both strains showed lower hyphal growth at the second harvest and mycelium of G. intraradices lost almost entirely its capacity to develop new mycelium in all choices presented. Lipid measurements showed this fungus did not use storage lipids to exploit the patches. S. calospora mycelium had reduced growth and colonisation ability but still showed some growth in the patches at the second harvest. A reduction in the content of NLFA 16:1w5 from the first to the second harvest suggested that S. calospora mycelium likely used storage lipids to sustain proliferation in the patches. The results indicated that S. calospora was more active and used more resources for foraging than G. intraradices; and that external mycelium foraging was maintained mainly with recently acquired plant carbon (C). This supported in general our hypothesis but showed as well that the two AMF strains had different strategies and resource allocation to forage. The overall low response of both AMF to the choices presented suggested that the responsiveness of mycelium searching freely in the substrate is lower than that observed in experimental systems in which the amendments have been placed in close contact with actively growing mycelium fronts in close vicinity with host roots.
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| 8. |
- Gormsen, Dagmar, et al.
(författare)
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Diversity of soil mite communities when managing plant communities on set-aside arable land
- 2006
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Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 31:1-2, s. 147-158
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Tidskriftsartikel (refereegranskat)abstract
- When restoring former agricultural land to more low-nutrient input ecosystems, the establishment of a plant community can be enhanced by sowing desirable species. In this study our aim was to determine whether management of the plant community influences the microarthropod community. We carried out a field experiment in three European countries on set-aside arable land and determined soil mites from the sites in Sweden, The Netherlands and Spain. Experimental plots on set-aside arable land were sown with high (15 species) or low (4 species) plant species seed mixtures; other plots were colonized naturally. A field with continued agricultural practices and a later successional site (target site) were used for comparison with the experimental plots. Soil from the later successional site was inoculated into half of the plots. Abandoning agricultural practices increased the density of mites at one site while the number of mite species was not affected. Sowing plant seeds had no effect on mite densities at any of the sites. The community composition of mites changed in response to management of the plant community, as shown by canonical correspondence analysis. Among the functional groups of mites, saprophytes generally dominated on all plots at all sites. Mites parasitic on insects were not present on fields with continued agricultural practice in Sweden and The Netherlands, and might thus be regarded as an indicator of an increase in trophic complexity in the sown and naturally colonized treatments. Predatory and plant parasitic mites showed no consistent pattern in relation to the treatments of the three sites. Soil inoculation treatment had only a minor impact on the soil mite communities.
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| 9. |
- Gustafsson, Stefan, 1976, et al.
(författare)
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Alumina/silicon carbide composites fabricated via in situ synthesis of nano-sized SiC particles
- 2009
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Ingår i: Ceramics International. - : Elsevier BV. - 0272-8842 .- 1873-3956. ; 35:3, s. 1293-1296
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Tidskriftsartikel (refereegranskat)abstract
- Alumina/silicon carbide composites have been fabricated by a new technique involving the in situ synthesis of nano-sized SiC particles. A mixture of alumina powder and silicon carbide precursors was prepared in an aqueous suspension. Green bodies were formed by cold isostatic pressing of granules obtained by freeze granulation, and pressureless sintered at 1750 °C for 4 h in an argon atmosphere. Mullite (10-20 vol%) formed in addition to SiC during sintering. The SiC particles were located predominantly to the interior of the mullite and alumina matrix grains. © 2008 Elsevier Ltd and Techna Group S.r.l.
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| 10. |
- Hallgren, Mattias, et al.
(författare)
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Competitive capabilities : a contingency perspective
- 2007
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Ingår i: Journal of Operations Management. - 0272-6963 .- 1873-1317.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In this paper we present and test an alternative model for competitive capabilities.Traditionally, a cumulative model has been viewed as having one sequence of buildingoperations capabilities in a firm in support of market needs, including quality,delivery, cost efficiency and flexibility. Although appealing as a conceptual model,empirical testing has not been able to fully support the cumulative model. This paperacknowledges the need for differentiated approaches to managing capability indifferent operating environments. The competitive capability model that is presented istested empirically using data from the High Performance Manufacturing (HPM) study,including three industries and seven countries – a total of 211 plants. The results showthat there is empirical support for differentiating the competitive capabilities; firmsproducing to stock follow a path of quality, delivery and cost, whereas those producingto customer order exhibit a capability path in the order of quality, delivery andflexibility. Thus, while quality and delivery are common, cost and flexibility acts asdifferentiators contingent upon the manufacturing environment.
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