| 1. |
- Holme, Petter, et al.
(författare)
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A zero-temperature study of vortex mobility in two-dimensional vortex glass models
- 2002
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Ingår i: Europhysics letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 60:3, s. 439-445
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Tidskriftsartikel (refereegranskat)abstract
- Three different vortex glass models are studied by examining the energy barrier against vortex motion cross the system. In the two-dimensional gauge glass this energy barrier is found to increase logarithmically with system size which opens up for the existence of low-temperature phase with zero resistivity. Associated with the large-energy barriers is breaking of ergodicity which explains why the well-established results from equilibrium studies could fail. The behavior of the more realistic random pinning model is however different with decreasing energy barriers and no finite critical temperature.
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| 2. |
- Lundström, Ulla, et al.
(författare)
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Advances in understanding the podzolization process resulting from a multidisciplinary study of three coniferous forest soils in the Nordic Countries
- 2000
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Ingår i: Geoderma. - 0016-7061 .- 1872-6259. ; 94:04-feb, s. 335-353
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Tidskriftsartikel (refereegranskat)abstract
- Geochemical, mineralogical, micromorphological, microbiological, hydrochemical and hpdrological joint investigations were performed at two coniferous podzolic sites in the north of Sweden and at one in the south of Finland. Mycorrhizal fungi were found to create numerous pens (3-10-mu m diameter) in many weatherable mineral grains in the eluvial (E) horizon. During the growing season, identified low molecular weight (LMW) organic acids such as citric, shikimic, oxalic and fumaric acids comprised 0.5-5% of the DOC and 0.5-15% of the total acidity in soil solutions. Between 20% and 40% of the dissolved Al was bound to the identified LMW organic acids. Mineral dissolution via complexing LMW acids, probably exuded in part by the mycorrhiza hyphae, is likely to be a major weathering process in podzols. We found no evidence for a decreasing C/metal ratio of the migrating organo-metal complexes that could explain the precipitation of secondary Fe and AL in the illuvial (B) horizon. Instead, microbial degradation of organic ligands resulting in the release of ionic,Al and Fe to the soil solution may he an important process facilitating the formation of solid Al-SI-OH and Fe-OH phases in the podzol B horizon. However, within the B horizon transport as proto-imogilite (PI) sols might be possible. In the B horizon, the extractable,Al and Fe was predominantly inorganic. The large specific surface area (SSA) removable by oxalate extraction, the high point of zero charge salt effect (PZSE), the low cation exchange capacity (CEC) and the high sulphate exchange capacity (SEC), painted to the presence of short-range ordered variable charge phases. Imogolite type material (ITM) was indeed identified in all B horizons by IR spectroscopy and crystalline imogolite was found in the deep B horizon of one profile. Mossbauer spectroscopy indicated that Fe in the form of ferrihydrite was formed by intergrowth with an Al-Si-OH phase. The high amounts of Fe and Al transported from the O to the E horizon indicate that there could be an upward transport of these elements before they are leached to the B horizon. We hypothesize that the LMW Al complexes an transported by hyphae to the mor (O) layer, partly released and subsequently complexed by high molecular weight (HMW) acids.
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| 3. |
- Olsson, Katarina, et al.
(författare)
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Vila vid denna källa
- 2004
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Ingår i: Konsten att rättsvetenskapa: den tysta kunskapen i juridisk forskning. - 9176785807 ; , s. 203-221
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Olsson, Lars E., 1971, et al.
(författare)
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The dyadic subsidy game: Effects of uncertain and changing subsidies on price setting
- 2004
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Ingår i: Poster presented at the 28th international congress of psychology, Beijing, China..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In order to reduce sales (production) of environmentally harmful products we investigate the effects of subsidies that compensate producers for what they do not sell. A repeated duopoly price-setting game with imperfect price competition was devised. The results show that higher subsidies led to reduced sales and, as a consequence, higher price, and that uncertainty regarding the size of the subsidy did not change this. Furthermore, competition was not eroded by introducing the subsidy. The results also indicate that the theoretical framework of dyadic price negotiation is applicable to the dyadic subsidy game. We conclude that such a subsidy system may be used as a regulating mechanism in order to reduce sales (and thereby production) of environmentally harmful products or as a tool to restrain the overharvesting of finite resources
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| 5. |
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| 6. |
- Olsson, P., et al.
(författare)
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Transition in the two-dimensional step model : A Kosterlitz-Thouless transition in disguise
- 2001
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 6305:5
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Tidskriftsartikel (refereegranskat)abstract
- Evidence for a Kosterlitz-Thouless transition in the two-dimensional (2D) step model is obtained from Monte Carlo determinations of the helicity modulus. It is argued that the free energy of a single vortex at the center of the system depends logarithmically on the system size in spite of the fact that the spin interaction is not harmonic for small differences in the spin angles. We conclude that this is the reason for the Kosterlitz-Thouless transition in the 2D step model and that the harmonic spin interaction not is a necessary requirement.
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| 7. |
- Pilesjö, Petter, et al.
(författare)
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Metoder för rumslig dataanalys
- 2000
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Ingår i: Geografisk Informationsbehandling. - 915405841 4 ; , s. 195-266
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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