| 1. |
- Ludwig, Hans-Günter, et al.
(författare)
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3D Hydrodynamical Modelling of the Solar Chromosphere
- 2003
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Ingår i: International Astronomical Union Symposium. - 158381163X ; 219, s. 40-40
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Konferensbidrag (refereegranskat)abstract
- We report on 3D radiation-hydrodynamics modelling of the non-magneticsolar atmosphere with emphasis on the problem of the acoustic heating ofthe chromosphere. Our models include the generation of acoustic waves inthe uppermost layers of the solar convection zone their propagationthrough the photospheric layers and their ultimate transformation intoshock fronts which are dissipated in the chromospheric layers. In thechromosphere we find a bimodal temperature distribution consisting of acool non-shocked and hot shocked gas component. The hot gas is locatedin small-scale filamentary structures associated with propagating shockfronts which evolve rapidly in time. The detailed spatial and temporalinformation provided by the models can be exploited to predictobservational diagnostics hitherto unavailable. We present syntheticimages of features in the millimetre and sub-millimetre radio continuumpotentially observable by the Atacama Large Millimetre Array (ALMA).
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| 2. |
- Philipsson, Jan, et al.
(författare)
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Genetic connectedness between seven European countries for performance in jumping competitions of warmblood riding horses
- 2009
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Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 120, s. 75-86
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this Study was to evaluate the genetic connectedness between seven European populations of show jumping horses. Data on stallions bred for jumping and their pedigree Lip to three generations were provided by seven countries, including 63 17 stallions and 22 324 different horses. Four different methods were used to estimate the genetic connectedness. Common stallions between countries varied from 0 to 309 and common horses from 130 to 1166. "Genetic similarities" were not the optimal measure of connectedness as number of progeny by Country by stallion was not balanced. Correlation between estimates of country effects was computed in a mixed model including the genetic value of horses (h(2) =0.20, all relationships included). For Germany, Belgium, France and The Netherlands, these correlations were 0.32 to 0.51 corresponding to a balanced scheme with I I to 19 progeny per stallion per country. Other correlations ranged from 0.08 to 0.27. Another method to evaluate the connectedness was (i) to Simulate a systematic difference between the true genetic level of countries, (ii) performing a BLUP and (iii) measuring the percentage of the initial difference that Could be found between the estimated genetic levels of the corresponding countries. In 50% of the country pairs, 50% or more of the initial genetic difference was estimated. It was concluded that the genetic connectedness will allow the estimation of genetic correlations. (c) 2009 Elsevier B.V. All rights reserved.
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| 3. |
- Román, Henrik, 1965-
(författare)
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Reformer
- 2009
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Ingår i: Vad påverkar resultaten i svensk grundskola?. - Stockholm : Skolverket. - 9789185545674 ; , s. 122-158
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Bellenberg, Sören, et al.
(författare)
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Proteomics Reveal Enhanced Oxidative Stress Responses and Metabolic Adaptation in Acidithiobacillus ferrooxidans Biofilm Cells on Pyrite
- 2019
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Ingår i: Frontiers in Microbiology. - : Frontiers Media S.A.. - 1664-302X. ; 10, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- Reactive oxygen species (ROS) cause oxidative stress and growth inhibition by inactivation of essential enzymes, DNA and lipid damage in microbial cells. Acid mine drainage (AMD) ecosystems are characterized by low pH values, enhanced levels of metal ions and low species abundance. Furthermore, metal sulfides, such as pyrite and chalcopyrite, generate extracellular ROS upon exposure to acidic water. Consequently, oxidative stress management is especially important in acidophilic leaching microorganisms present in industrial biomining operations, especially when forming biofilms on metal sulfides. Several adaptive mechanisms have been described, but the molecular repertoire of responses upon exposure to pyrite and the presence of ROS are not thoroughly understood in acidophiles. In this study the impact of the addition of H2O2 on iron oxidation activity in Acidithiobacillus ferrooxidans DSM 14882(T) was investigated. Iron(II)- or sulfur-grown cells showed a higher sensitivity toward H2O2 than pyrite-grown ones. In order to elucidate which molecular responses may be involved, we used shot-gun proteomics and compared proteomes of cells grown with iron(II)-ions against biofilm cells, grown for 5 days in presence of pyrite as sole energy source. In total 1157 proteins were identified. 213 and 207 ones were found to have increased levels in iron(II) ion-grown or pyrite-biofilm cells, respectively. Proteins associated with inorganic sulfur compound (ISC) oxidation were among the latter. In total, 80 proteins involved in ROS degradation, thiol redox regulation, macromolecule repair mechanisms, biosynthesis of antioxidants, as well as metal and oxygen homeostasis were found. 42 of these proteins had no significant changes in abundance, while 30 proteins had increased levels in pyrite-biofilm cells. New insights in ROS mitigation strategies, such as importance of globins for oxygen homeostasis and prevention of unspecific reactions of free oxygen that generate ROS are presented for A. ferrooxidans biofilm cells. Furthermore, proteomic analyses provide insights in adaptations of carbon fixation and oxidative phosphorylation pathways under these two growth conditions.
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| 5. |
- Bellenberg, Sören, et al.
(författare)
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Towards Bioleaching of a Vanadium Containing Magnetite for Metal Recovery
- 2021
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Ingår i: Frontiers in Microbiology. - : Frontiers Media S.A.. - 1664-302X. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Vanadium - a transition metal - is found in the ferrous-ferric mineral, magnetite. Vanadium has many industrial applications, such as in the production of high-strength low-alloy steels, and its increasing global industrial consumption requires new primary sources. Bioleaching is a biotechnological process for microbially catalyzed dissolution of minerals and wastes for metal recovery such as biogenic organic acid dissolution of bauxite residues. In this study, 16S rRNA gene amplicon sequencing was used to identify microorganisms in Nordic mining environments influenced by vanadium containing sources. These data identified gene sequences that aligned to the Gluconobacter genus that produce gluconic acid. Several strategies for magnetite dissolution were tested including oxidative and reductive bioleaching by acidophilic microbes along with dissimilatory reduction by Shewanella spp. that did not yield significant metal release. In addition, abiotic dissolution of the magnetite was tested with gluconic and oxalic acids, and yielded 3.99 and 81.31% iron release as a proxy for vanadium release, respectively. As a proof of principle, leaching via gluconic acid production by Gluconobacter oxydans resulted in a maximum yield of 9.8% of the available iron and 3.3% of the vanadium. Addition of an increased concentration of glucose as electron donor for gluconic acid production alone, or in combination with calcium carbonate to buffer the pH, increased the rate of iron dissolution and final vanadium recoveries. These data suggest a strategy of biogenic organic acid mediated vanadium recovery from magnetite and point the way to testing additional microbial species to optimize the recovery.
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| 10. |
- Kroksmark, Tomas
(författare)
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Skola i förändringstider
- 1996
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Ingår i: Lärarnas tidning. - 1101-2633. ; :9, s. -23
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 11. |
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| 12. |
- Pfalzner, S., et al.
(författare)
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The formation of the solar system
- 2015
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 90:6
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The solar system started to form about 4.56 Gyr ago and despite the long intervening time span, there still exist several clues about its formation. The three major sources for this information are meteorites, the present solar system structure and the planet-forming systems around young stars. In this introduction we give an overview of the current understanding of the solar system formation from all these different research fields. This includes the question of the lifetime of the solar protoplanetary disc, the different stages of planet formation, their duration, and their relative importance. We consider whether meteorite evidence and observations of protoplanetary discs point in the same direction. This will tell us whether our solar system had a typical formation history or an exceptional one. There are also many indications that the solar system formed as part of a star cluster. Here we examine the types of cluster the Sun could have formed in, especially whether its stellar density was at any stage high enough to influence the properties of today's solar system. The likelihood of identifying siblings of the Sun is discussed. Finally, the possible dynamical evolution of the solar system since its formation and its future are considered.
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| 13. |
- Ribeiro, Luiz Antonio, et al.
(författare)
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Concentration effects on intrachain polaron recombination in conjugated polymers
- 2015
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry. - 1463-9076 .- 1463-9084. ; 17:2, s. 1299-1308
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Tidskriftsartikel (refereegranskat)abstract
- The influence of different charge carrier concentrations on the recombination dynamics between oppositely charged polarons is numerically investigated using a modified version of the Su-Schrieffer-Heeger (SSH) model that includes an external electric field and electron-electron interactions. Our findings show that the external electric field can play the role of avoiding the formation of excited states (polaron-exciton and neutral excitation) leading the system to a dimerized lattice. Interestingly, depending on a suitable balance between the polaron concentration and the electric field strength, the recombination mechanism can form stable polaron-excitons or neutral excitations. These results may provide guidance to improve the electroluminescence efficiency in Polymer Light Emitting Diodes.
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| 14. |
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