| 1. |
- Angerås, Oskar, 1976, et al.
(författare)
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Impact of Thrombus Aspiration on Mortality, Stent Thrombosis, and Stroke in Patients with ST-Segment-Elevation Myocardial Infarction: A Report From the Swedish Coronary Angiography and Angioplasty Registry
- 2018
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Ingår i: Journal of the American Heart Association. - : John Wiley & Sons. - 2047-9980. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Background-Thrombus aspiration is still being used in a substantial number of patients despite 2 large randomized clinical trials showing no favorable effect of routine thrombus aspiration during primary percutaneous coronary intervention in patients with STsegment- elevation myocardial infarction. The aim of this observational study was to evaluate the impact of thrombus aspiration on mortality, stent thrombosis, and stroke using all available data from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR). Methods and Results--We identified 42 829 consecutive patients registered in SCAAR between January 2005 and September 2014 who underwent percutaneous coronary intervention for ST-segment-elevation myocardial infarction. Thrombus aspiration was used in 25% of the procedures. We used instrumental variable analysis with administrative healthcare region as the treatmentpreference instrumental variable to evaluate the effect of thrombus aspiration on mortality, stent thrombosis, and stroke. Thrombus aspiration was not associated with mortality at 30 days (risk reduction: -1.2; 95% confidence interval [CI] , -5.4 to 3.0; P=0.57) and 1 year (risk reduction: -2.4; 95% CI, -7.6 to 3.0; P=0.37). Thrombus aspiration was associated with a lower risk of stent thrombosis both at 30 days (risk reduction: -2.7; 95% CI, -4.1 to -1.4; P < 0.001) and 1 year (risk reduction: -3.5; 95% CI, -5.3 to -1.7; P < 0.001). In-hospital stroke and neurologic complications did not differ between groups (risk reduction: 0.1; 95% CI, -0.8 to 1.1; P=0.76). Conclusions--Mortality was not different between the groups. Thrombus aspiration was associated with decreased risk of stent thrombosis. Our study provides important evidence for the external validity of previous randomized studies regarding mortality.
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| 2. |
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| 3. |
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| 4. |
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| 5. |
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| 6. |
- Behrens, Jane W., et al.
(författare)
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Personality- and size-related metabolic performance in invasive round goby (Neogobius melanostomus)
- 2020
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Ingår i: Physiology and Behavior. - : Elsevier. - 0031-9384 .- 1873-507X. ; 215, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- Differences between individuals in behavioral type (i.e. animal personality) are ecologically and evolutionarily important because they can have significant effects on fitness components such as growth and predation risk. In the present study we are used the invasive round goby (Neogobius melanostomus) from an established population in controlled experiments to examine the relationships among personality, metabolic performance, and growth rate (inferred as size-at-age). Boldness was measured as the time to return to normal behavior after a simulated predator attack, where fish with shorter freezing times were categorized as "bold" and fish with longer times were categorized as "shy." We show that bold fish have significantly higher standard metabolic rate (SMR) than their shy conspecifics, whereas there was no difference between personality types in their maximum metabolic rate (MMR) or aerobic scope (AS). Bold fish furthermore had a smaller size-at-age as compared to shy fish. Together this provides evidence of a metabolic underpinning of personality where the high-SMR bold fish require more resources to sustain basic life functions than their low-SMR shy conspecifics, indicating that bold round goby from established populations with high densities (and high competition for food) pay a price of reduced growth rate.
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| 7. |
- Edebol Carlman, Hanna M. T., et al.
(författare)
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Probiotic Mixture Containing Lactobacillus helveticus, Bifidobacterium longum and Lactiplantibacillus plantarum Affects Brain Responses to an Arithmetic Stress Task in Healthy Subjects : A Randomised Clinical Trial and Proof-of-Concept Study
- 2022
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Ingår i: Nutrients. - : MDPI. - 2072-6643. ; 14:7
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Tidskriftsartikel (refereegranskat)abstract
- Probiotics are suggested to impact physiological and psychological stress responses by acting on the gut-brain axis. We investigated if a probiotic product containing Bifidobacterium longum R0175, Lactobacillus helveticus R0052 and Lactiplantibacillus plantarum R1012 affected stress processing in a double-blinded, randomised, placebo-controlled, crossover proof-of-concept study (NCT03615651). Twenty-two healthy subjects (24.2 ± 3.4 years, 6 men/16 women) underwent a probiotic and placebo intervention for 4 weeks each, separated by a 4-week washout period. Subjects were examined by functional magnetic resonance imaging while performing the Montreal Imaging Stress Task (MIST) as well as an autonomic nervous system function assessment during the Stroop task. Reduced activation in regions of the lateral orbital and ventral cingulate gyri was observed after probiotic intervention compared to placebo. Significantly increased functional connectivity was found between the upper limbic region and medioventral area. Interestingly, probiotic intervention seemed to predominantly affect the initial stress response. Salivary cortisol secretion during the task was not altered. Probiotic intervention did not affect cognitive performance and autonomic nervous system function during Stroop. The probiotic intervention was able to subtly alter brain activity and functional connectivity in regions known to regulate emotion and stress responses. These findings support the potential of probiotics as a non-pharmaceutical treatment modality for stress-related disorders.
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| 8. |
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| 9. |
- Emmerlich, Jens, 1974-, et al.
(författare)
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Growth of Ti3SiC2 thin films by elemental target magnetron sputtering
- 2004
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 96:9, s. 4817-4826
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Tidskriftsartikel (refereegranskat)abstract
- Epitaxial Ti3SiC2(0001) thin films have been deposited by dc magnetron sputtering from three elemental targets of Ti, C, and Si onto MgO(111) and Al2O3(0001) substrates at temperatures of 800–900 °C. This process allows composition control to synthesize Mn + 1AXn (MAX) phases (M: early transition metal; A: A-group element; X: C and/or N; n = 1–3) including Ti4SiC3. Depositions on MgO(100) substrates yielding the Ti–Si–C MAX phases with (105), as the preferred orientation. Samples grown at different substrate temperatures, studied by means of transmission electron microscopy and x-ray diffraction investigations, revealed the constraints of Ti3SiC2 nucleation due to kinetic limitations at substrate temperatures below 700 °C. Instead, there is a competitive TiCx growth with Si segregation to form twin boundaries or Si substitutional incorporation in TiCx. Physical properties of the as-deposited single-crystal Ti3SiC2 films were determined. A low resistivity of 25 µ cm was measured. The Young's modulus, ascertained by nanoindentation, yielded a value of 343–370 GPa. For the mechanical deformation response of the material, probing with cube corner and Berkovich indenters showed an initial high hardness of almost 30 GPa. With increased maximum indentation loads, the hardness was observed to decrease toward bulk values as the characteristic kink formation sets in with dislocation ordering and delamination at basal planes.
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| 10. |
- Engström, Per, et al.
(författare)
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Loss evasion and tax aversion
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The objective of this paper is to study if taxpayers behave in a loss averse manner when filing their tax returns. This is important for tax design but also for understanding human behavior in general. The predictions of prospect theory can be contrasted to those of expected utility theory. We use data for 3.6 million Swedish taxpayers for the income year 2006. Our research method is quasi-experimental using a regression kink and discontinuity approach. We also use an alternative instrumental-variables approach. There is strong evidence of loss aversion. We estimate the coefficient of loss aversion using actual behavior and the instrument-variables approach. Our estimate is very close to the estimates reported in the experimental literature.
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| 11. |
- Ericsson, Philip, et al.
(författare)
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Personality-dependent inter- and intraspecific foraging competition in the invasive round goby, Neogobius melanostomus
- 2021
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Ingår i: Journal of Fish Biology. - : Wiley-Blackwell. - 0022-1112 .- 1095-8649. ; 98:5, s. 1234-1241
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Tidskriftsartikel (refereegranskat)abstract
- This study examines the impact of boldness on foraging competition of the highly invasive round goby Neogobius melanostomus Pallas 1815. Individual risk tolerance, or boldness, was measured as the time to resume movement after a simulated predation strike. Fish that resumed movement faster were categorized as "bold," fish that took more time to resume movement were categorized as "shy" and those that fell in between these two categories were determined to have "intermediate" boldness. Competitive impacts of boldness in N. melanostomus were determined in a laboratory foraging experiment in which interspecific (juvenile Atlantic cod Gadus morhua Linnaeus 1758) and intraspecific (intermediate N. melanostomus) individuals were exposed to either bold or shy N. melanostomus competitors. G. morhua consumed fewer prey when competing with bold N. melanostomus than when competing with shy N. melanostomus, whereas intermediately bold N. melanostomus foraging was not affected by competitor boldness. Bold and shy N. melanostomus consumed similar amounts of prey, and the number of interactions between paired fish did not vary depending on the personality of N. melanostomus individuals. Therefore, intraspecific foraging competition was not found to be personality dependent. This study provides evidence that individual differences in boldness can mediate competitive interactions in N. melanostomus; nonetheless, results also show that competition is also governed by other mechanisms that require further study.
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| 12. |
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| 13. |
- Hammarström, Per, 1972-, et al.
(författare)
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Protein substrate binding induces conformational changes in the chaperonin GroEL : A suggested mechanism for unfoldase activity
- 2000
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 275:30, s. 22832-22838
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Tidskriftsartikel (refereegranskat)abstract
- Chaperonins are molecules that assist proteins during folding and protect them from irreversible aggregation. We studied the chaperonin GroEL and its interaction with the enzyme human carbonic anhydrase II (HCA II), which induces unfolding of the enzyme. We focused on conformational changes that occur in GroEL during formation of the GroEL-HCA II complex. We measured the rate of GroEL cysteine reactivity toward iodo[2-(14)C]acetic acid and found that the cysteines become more accessible during binding of a cysteine free mutant of HCA II. Spin labeling of GroEL with N-(1-oxy1-2,2,5,5-tetramethyl-3-pyrrolidinyl)iodoacetamide revealed that this additional binding occurred because buried cysteine residues become accessible during HCA II binding. In addition, a GroEL variant labeled with 6-iodoacetamidofluorescein exhibited decreased fluorescence anisotropy upon HCA II binding, which resembles the effect of GroES/ATP binding. Furthermore, by producing cysteine-modified GroEL with the spin label N-(1-oxyl-2,2,5,5-tetramethyl-3-pyrrolidinyl)iodoacetamide and the fluorescent label 5-((((2-iodoacetyl)amino)ethyl)amino)naphthalene-1-sulfonic acid, we detected increases in spin-label mobility and fluorescence intensity in GroEL upon HCA II binding. Together, these results show that conformational changes occur in the chaperonin as a consequence of protein substrate binding. Together with previous results on the unfoldase activity of GroEL, we suggest that the chaperonin opens up as the substrate protein binds. This opening mechanism may induce stretching of the protein, which would account for reported unfoldase activity of GroEL and might explain how GroEL can actively chaperone proteins larger than HCA II.
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| 14. |
- Hansson, Lars-Anders, et al.
(författare)
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Food-chain length alters community responses to global change in aquatic systems
- 2013
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Ingår i: Nature Climate Change. - : Springer Science and Business Media LLC. - 1758-678X .- 1758-6798. ; 3, s. 228-233
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Tidskriftsartikel (refereegranskat)abstract
- Synergies between large-scale environmental changes, such as climate change1 and increased humic content (brownification)2, will have a considerable impact on future aquatic ecosystems. On the basis of modelling, monitoring and experimental data, we demonstrate that community responses to global change are determined by food-chain length and that the top trophic level, and every second level below, will benefit from climate change, whereas the levels in between will suffer. Hence, phytoplankton, and thereby algal blooms, will benefit from climate change in three-, but not in two-trophic-level systems. Moreover, we show that both phytoplankton (resource) and zooplankton (consumer) advance their spring peak abundances similarly in response to a 3 °C temperature increase; that is, there is no support for a consumer/resource mismatch in a future climate scenario. However, in contrast to other taxa, cyanobacteria—known as toxin-producing nuisance phytoplankton3—benefit from a higher temperature and humic content irrespective of the food-chain composition. Our results are mirrored in natural ecosystems. By mechanistically merging present food-chain theory with large-scale environmental and climate changes, we provide a powerful framework for predicting and understanding future aquatic ecosystems and their provision of ecosystem services and water resources.
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| 15. |
- Koppejan, Japp, et al.
(författare)
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Health and safety Aspects of Solid Biomass Storage, Transportation and Feeding
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This publication focuses on the health and safety issues of the supply chain of solid biofuels with the objective to highlight commonly used mitigation methodologies to promote a better working environment when dealing with solid biofuels. It has been compiled as a joint effort by experts active in Tasks 32, 36, 37 and 40 of the IEA Bioenergy Agreement, with their own specific fields of expertise. Only through this cooperation, it was possible to touch upon the full range of issues in one publication that one may come across when developing projects in which solid biomass fuels are produced, traded or used. The properties of a biomass material and the intended use determine how the material should be safely transported and stored. Self-heating, off-gassing and dust explosions are significant challenges for the industry that have already resulted in significant losses of capital investments and even tragic loss of life. Likewise, exposure to biologically active material, such as moulds and spores may form a serious hazard for the health of workers involved. With the growth of the bioenergy sector, it is important not only that opportunities for bioenergy are implemented in an efficient economic manner, but also safely.
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| 16. |
- Larsson, Ida, et al.
(författare)
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Assessment of the Self-heating Potential of Wood Pellets
- 2012
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The use of biomass pellets is increasing. As a consequence, large indoor storage facilities are needed along the transportation chain. The increased production volumes, transportation, handling and storage of pellets result in increased risks. A number of fire incidents due to spontaneous ignition in wood pellets have been reported. Increased efforts concerning safety and quality assurance are, therefore, important. The aim of the present work is to provide methods for estimating risks for self-heating from pellets stored in bulk quantities. The experimental work ranges from small-scale characterizations to medium-scale storage tests and includes several different types of pellets. One aim has been to develop small scale screening methods to assess the propensity for self-heating, thereby trying to define the specific type of “activity” occurring in the pellets as well as characterising it. Isothermal calorimetry (micro calorimeter) has been used as small scale screening test method and the results has then been validated with crossing point tests and in medium scale tests (1 m3). Thirteen samples from different types of pellets have been ranked relative to each other in micro calorimeter tests and two pellet types; one “reactive” and one “less reactive” were also tested for validation in crossing point and medium scale. The results clearly reveal that different activity levels of the pellets can be measured using small scale screening methods.
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| 17. |
- Larsson, Ida, et al.
(författare)
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Medium-scale reference tests and calculations of spontaneous ignition in wood pellets - the LUBA project
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The use of biomass pellets is increasing. As a consequence, large indoor storage facilities are needed along the transportation chain. The increased production volumes, transportation, handling and storage of pellets result in increased risks. A number of fire incidents due to spontaneous ignition in wood pellets have been reported. Increased efforts concerning safety and quality assurance are, therefore, important. The aim of present work is to provide methods for estimating risks for self-heating from pellets stored in bulk quantities. This report compares medium scale tests of pellets in bulk with smaller screening test; micro calorimeter and crossing point. Two types of pellets; one “reactive” and one “less reactive” were compared. Kinetic parameters from the crossing point and micro calorimeter tests was used as input data for Frank-Kamenetskii calculations and compared with the medium scale test results. Calculations of the critical ambient temperature and time to self-ignition have also been preformed on four different types of representative types of full scale storages that either exist today or might be possible in the future. The results clearly reveal that results in medium scale can be predicted by using results from small scale screening methods like isothermal calorimetry or crossing point. The small scale test methods show the same indications as medium scale when comparing reactive and less active pellet types. The medium-scale tests were effective in separating the self-heating activity of the two types of pellets investigated.
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| 18. |
- Larsson, Ida, et al.
(författare)
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Small scale screening tests to assess the self-heating potential of wood pellets
- 2013
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Ingår i: Interflam 2013. - London, UK : Interscience Communications. ; , s. 623-628
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The use of biomass pellets is increasing. As a consequence, large indoor storage facilities are needed along the transportation chain. A number of fire incidents due to spontaneous ignition in wood pellets have been reported. The aim of the present work is to provide methods for estimating risks for self-heating from pellets stored in bulk quantities. The experimental work ranges from small-scale characterizations to medium-scale storage tests and includes different types of pellets. One aim has been to develop small scale screening methods to assess the propensity for self-heating, thereby trying to define the specific type of “activity” occurring in the pellets as well as characterising it. Isothermal calorimetry (micro calorimeter) has been used as small scale screening test method and the results has then been validated with crossing point tests and in medium scale tests (1 m3). Thirteen samples from different types of pellets have been ranked relative to each other in micro calorimeter tests and two pellet types; one “reactive” and one “less reactive” were also tested for validation in crossing point and medium scale. The results clearly reveal that different activity levels of the pellets can be measured using small scale screening methods.
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| 19. |
- Larsson, Ida, et al.
(författare)
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Temperature Measurements and Examination of Self-heating in Large Scale storage of Wood Pellets
- 2014
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Ingår i: World Bioenergy 2014. - Jönköping, Sweden.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper summarizes the experimental data from a large-scale storage test performed within the European project called SafePellets. Temperature measurements were made inside a silo with a capacity of storing 3000 ton of wood pellets, from August to October in 2013. The purpose of the test was to examine the self-heating of the wood pellets, where and when it occurs, how it spreads and if it could be connected to certain events. For temperature measurements, both the temperature cables belonging to the silo temperature surveillance system and thermocouples mounted by SP at the cables and on the in/out-side walls of the silo were used. The results clearly reveal that self-heating occurs almost instantly after start of filling the silo and temperatures above 40 °C inside the pellets bulk is regular. The temperature surveillance system, which was set to give an alarm signal for high temperatures, was activated several times during the test period and temperatures exceeding 60 °C were registered at several occasions. Measurements above the pellet surface also show that this headspace temperature varies much with the outside ambient temperature and the sunlight radiation. A sunny summer’s day, the headspace temperature could easily reach above 40 °C, which will influence the pellet bulk. The project also emphasized an important problem when it comes to silo storage. The problem of temperature sensor cables inside the silo not always hanging where they are supposed to be was observed in the test and dealt with.
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| 20. |
- Ling, Johan, 1968, et al.
(författare)
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Moving metals II: Provenancing Scandinavian Bronze Age artefacts by lead isotope and elemental analyses
- 2014
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Ingår i: Journal of Archaeological Science. - : Elsevier BV. - 0305-4403 .- 1095-9238. ; 41, s. 106-132
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Tidskriftsartikel (refereegranskat)abstract
- The first part of this research published previously proved without doubt that the metals dated to the Nordic Bronze Age found in Sweden were not smelted from the local copper ores. In this second part we present a detailed interpretation of these analytical data with the aim to identify the ore sources from which these metals originated. The interpretation of lead isotope and chemical data of 71 Swedish Bronze Age metals is based on the direct comparisons between the lead isotope data and geochemistry of ore deposits that are known to have produced copper in the Bronze Age. The presented interpretations of chemical and lead isotope analyses of Swedish metals dated to the Nordic Bronze Age are surprising and bring some information not known from previous work. Apart from a steady supply of copper from the Alpine ores in the North Tyrol, the main sources of copper seem to be ores from the Iberian Peninsula and Sardinia. Thus from the results presented here a new complex picture emerges of possible connectivities and flows in the Bronze Age between Scandinavia and Europe. © 2013 Elsevier Ltd.
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| 21. |
- Ling, Johan, 1968, et al.
(författare)
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Moving metals or indigenous mining? : Provenancing Scandinavian Bronze Age artefacts by leadisotopes and trace elements
- 2013
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Ingår i: Journal of Archaeological Science. - : Elsevier BV. - 0305-4403 .- 1095-9238. ; 40:1, s. 291-304
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study is to further the discussion as to whether copper was extracted locally or imported to Sweden during the Bronze Age or if both of these practices could have coexisted. For this purpose, we have carried out lead isotope and chemical analyses of 33 bronze items, dated between 1600BC and 700BC. Among these are the famous Fröslunda shields and the large scrap hoard from Bräckan and other items from three regions in southern Sweden which are also renowned for their richness in copper ores. It is obvious from a comparison that the element and lead isotope compositions of the studied bronze items diverge greatly from those of spatially associated copper ores. Nor is there any good resemblance with other ores from Scandinavia, and it is concluded that the copper in these items must have been imported from elsewhere. The results furthermore indicate that there are variations in metal supply that are related to chronology, in agreement with other artefacts from Scandinavia as well as from other parts of Europe. Altogether these circumstances open up for a discussion regarding Scandinavia’s role in the maritime networks during the Bronze Age.
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| 22. |
- Lönnermark, Anders, 1968-, et al.
(författare)
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Biobränslen och avfall - Brandsäkerhet i samband med lagring
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In the report fire risks with handling and storage of different types of biofuels or waste are discussed. The report gives an overview of different types of biofuels, future trends, different ways of storage, experiences from occurred fires, and previous or ongoing research project within the field. The EC Directive on landfill of waste together with the need and interest for biofuels have resulted in increased amounts and a new type of storages. This also means new types of risks. There is therefore a great need for knowledge on the risks for spontaneous ignition and fire characteristics for these fuels and storages. If a fire occurs it can lead to significant problems with emissions and in many cases the rescue services have problems with handling these fires. The fires can also lead to large economic losses. It is, therefore, important to know both how to avoid and how to facilitate extinguishment of these fires. The information gathered and presented in the report has been used to develop a proposal for a research programme, which is also presented in the report. The report deals mainly with solid biofuels and waste, but discussions on liquids and gaseous fuels are also included.
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| 23. |
- Lönnermark, Anders, 1968-, et al.
(författare)
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Fire Safety of Waste Storage
- 2010
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Ingår i: PROCEEDINGS. ; , s. 51-62
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The EC Directive on landfill of waste and the development of different national regulations, together with the need and interest for biofuels, have resulted in more extensive handling and storage of these products. Calorific value and bulk density are for most fractions lower than for example oil, which translates into a further increase in volumes of fuel needed for a given amount of energy. Since the material is to be used as a high-grade fuel, higher requirements are placed on the storage technology. There will also probably be strong desire to place stocks in direct connection with for example a specific industry or co-generation plant, to minimize the need for transport. Overall, this means that very large production and handling facilities with large stocks will be required. These new types of storages also mean new types of risks. There is therefore a great need for knowledge on the risks for spontaneous ignition, fire characteristics, and risk for fire spread for these fuels and storages. If a fire occurs it can lead to significant problems with emissions and in many cases the rescue services have problems with handling these fires. These fires can also lead to large economic losses. It is, therefore, important to know both how to avoid and how to facilitate extinguishment of these fires.In the paper some trends regarding storage of waste are discussed together with the risks for self-heating and emissions. Experiences from real fires are presented and some existing guidelines for storage of waste are discussed.
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| 24. |
- Lönnermark, Anders, 1968-, et al.
(författare)
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Self-heating and Off-gassing from Biomass Pellets during Storage
- 2012
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The use of biomass pellets is increasing. As a consequence,large indoor storage facilities are needed along the transportation line. Theincreased production volumes, transportation, handling and storage of pellets resultin increased risks. A number of fire incidents due to spontaneous ignition inwood pellets storages and accidents due to CO intoxication have been reported.Increased efforts concerning safety and quality assurance are, therefore,important. The aim of the present work is to provide methods for estimatingrisks for self-heating of and off-gassing from pellets stored in bulk. Theexperimental work ranges from small-scale characterizations to large-scalestorage tests and includes several different types of pellets. One aim has been to develop smallscale screening methods to assess the propensity for self-heating andoff-gassing, thereby trying to define the specific type of “activity” occurringin the pellets as well as characterising it. In addition to using said methods,isothermal calorimetry (micro calorimeter) and Oxipres (oxygen depletion), theformation of different gases (e.g. aldehydes) was analyzed. Thirteen samples from different types of pellets havebeen ranked relative to each other. Effects of processes like aging can also beseen in the results. The results clearly reveal that different activity levelsof the pellets can be measured using small scale screening methods and thatthere are certain correlations between off-gassing and heat development, althoughthese are not yet fully understood.
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| 25. |
- Lönnermark, Anders, 1968-, et al.
(författare)
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Small-scale methods for assessment of risk for self-heating of biomass pellets
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- One major concern when it comes to storage of wood pellets is the risk for self-heating. The propensity for self-heating varies between different types of pellets. It also depends on how the pellets have been handled and on the storage conditions, e.g. the temperature and humidity. Within the framework of the research project “Large scale Utilization of Biopellets for Energy Applications –LUBA” different laboratory-scale methods have been used to study different thermal properties and the propensity for self-heating for different types of pellets. The different methods used include micro calorimetry also called isothermal calorimetry, basket-heating tests and transient plane source (TPS). In total 21 different pellets samples were tested in the micro calorimeter, three in the basket-heating test and three in the TPS. The samples showed significant differences in propensity for self-heating. Differences could be seen both between different types of pellets and depending on the age of the pellets. Comparing the reactivity rates from the basket-heating tests and those from the isothermal calorimetry tests with the same type of pellets, both methods gave the same ranking of reactivity. It was shown that the TPS-method is applicable for the determination of thermal properties both for measurements on single pellets and for measurement on bulk pellet material.
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| 26. |
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| 27. |
- Mohammad, Moman A., et al.
(författare)
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Incidence and outcome of myocardial infarction treated with percutaneous coronary intervention during COVID-19 pandemic
- 2020
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Ingår i: Heart. - : BMJ Publishing Group Ltd. - 1355-6037 .- 1468-201X. ; 106:23, s. 1812-1818
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Most reports on the declining incidence of myocardial infarction (MI) during the COVID-19 have either been anecdotal, survey results or geographically limited to areas with lockdowns. We examined the incidence of MI during the COVID-19 pandemic in Sweden, which has remained an open society with a different public health approach fighting COVID-19.METHODS: We assessed the incidence rate (IR) as well as the incidence rate ratios (IRRs) of all MI referred for coronary angiography in Sweden using the nationwide Swedish Coronary Angiography and Angioplasty Registry (SCAAR), during the COVID-19 pandemic in Sweden (1 March 2020-7 May 2020) in relation to the same days 2015-2019.RESULTS: A total of 2443 MIs were referred for coronary angiography during the COVID-19 pandemic resulting in an IR 36 MIs/day (204 MIs/100 000 per year) compared with 15 213 MIs during the reference period with an IR of 45 MIs/day (254 MIs/100 000 per year) resulting in IRR of 0.80, 95% CI (0.74 to 0.86), p<0.001. Results were consistent in all investigated patient subgroups, indicating no change in patient category seeking cardiac care. Kaplan-Meier event rates for 7-day case fatality were 439 (2.3%) compared with 37 (2.9%) (HR: 0.81, 95% CI (0.58 to 1.13), p=0.21). Time to percutaneous coronary intervention (PCI) was shorter during the pandemic and PCI was equally performed, indicating no change in quality of care during the pandemic.CONCLUSION: The COVID-19 pandemic has significantly reduced the incidence of MI referred for invasive treatment strategy. No differences in overall short-term case fatality or quality of care indicators were observed.
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| 28. |
- Nilsson, Anna, et al.
(författare)
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Frequent detection of respiratory agents by multiplex PCR on oropharyngeal samples in Swedish school-attending adolescents
- 2012
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 44, s. 393-397
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Tidskriftsartikel (refereegranskat)abstract
- Background: Respiratory agents may be detected in the oropharynx of healthy individuals. The extent of this condition and the reasons behind it are largely unknown. The objective of this study was to determine the factors associated with the presence of respiratory agents in the oropharynx of adolescents healthy enough to attend school activities. Methods: On a single day in December, samples from the posterior wall of the oropharynx of adolescents aged 1015 y were obtained using cotton-tipped swabs. The samples were analyzed by real-time polymerase chain reaction (PCR) for the presence of 13 respiratory viruses and 2 bacteria (Mycoplasma pneumoniae and Chlamydophila pneumoniae). Results: Out of the 232 adolescents sampled, 67 (29%) had any respiratory symptom. A positive PCR result was found in 50 individuals (22%). Human rhinovirus was the most commonly found agent. Respiratory agents were significantly more frequent in the younger age group (1013 y) than in the older age group (1415 y): 26% (38/148) vs 14% (12/84), respectively; p = 0.04. Cough was the only symptom that was more common among individuals with a positive PCR test than among those with a negative PCR test: 8/50 (16%) vs 11/182 (6%); p = 0.02. Family size and class size were not associated with the likelihood of a positive PCR test. Conclusions: The presence of respiratory agents in the oropharynx is a frequent finding among adolescents healthy enough to attend school activities. The high prevalence was found to be associated with young age, but not with the size of the family or class. © 2012 Informa Healthcare.
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| 29. |
- Olofsson, Henrik, 1972, et al.
(författare)
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A spectral line survey of Orion KL in the bands 486-492 and 541-577 GHz with the Odin satellite. I. The observational data
- 2007
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 476:number 2, December III, s. 791-806
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Tidskriftsartikel (refereegranskat)abstract
- Aims.Spectral line surveys are useful since they allow identification of new molecules and new lines in uniformly calibrated data sets. The subsequent multi-transition analysis will provide improved knowledge of molecular abundances, cloud temperatures and densities, and may also reveal previously unsuspected blends of molecular lines, which otherwise may lead to erroneous conclusions. Nonetheless, large portions of the sub-millimetre spectral regime remain unexplored due to severe absorptions by H2O and O2 in the terrestrial atmosphere. The purpose of the measurements presented here is to cover wavelength regions at and around 0.55 mm - regions largely unobservable from the ground.Methods.Using the Odin astronomy/aeronomy satellite, we performed the first spectral survey of the Orion KL molecular cloud core in the bands 486-492 and 541-576 GHz with rather uniform sensitivity (22-25 mK baseline noise). Odin's 1.1 m size telescope, equipped with four cryo-cooled tuneable mixers connected to broad band spectrometers, was used in a satellite position-switching mode. Two mixers simultaneously observed different 1.1 GHz bands using frequency steps of 0.5 GHz (25 h each). An on-source integration time of 20 h was achieved for most bands. The entire campaign consumed ~1100 orbits, each containing one hour of serviceable astro-observation.Results.We identified 280 spectral lines from 38 known interstellar molecules (including isotopologues) having intensities in the range 80 to 0.05 K. An additional 64 weak lines remain unidentified. Apart from the ground state rotational 11,0-10,1 transitions of ortho-H2O, H218O and H217O, the high energy 62,4-71,7 line of para-H2O (Eu=867$\,$K) and the HDO(20,2-11,1) line have been observed, as well as the 10-01 lines from NH3 and its rare isotopologue 15NH3. We suggest assignments for some unidentified features, notably the new interstellar molecules ND and SH-. Severe blends have been detected in the line wings of the H218O, H217O and 13CO lines changing the true linewidths of the outflow emission.
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| 30. |
- Persson, Anders, et al.
(författare)
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Trophic interactions
- 2018
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Ingår i: Biology and ecology of pike. - Boca Raton : CRC Press. - 9781482262902
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Bokkapitel (refereegranskat)
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| 31. |
- Persson, Carina, 1964, et al.
(författare)
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A spectral line survey of Orion KL in the bands 486-492 and 541-577 GHz with the Odin satellite. II. Data analysis
- 2007
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 476:2, December III, s. 807-827
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Tidskriftsartikel (refereegranskat)abstract
- Aims.We investigate the physical and chemical conditions in a typical star forming region, including an unbiased search for new molecules in a spectral region previously unobserved.Methods.Due to its proximity, the Orion KL region offers a unique laboratory of molecular astrophysics in a chemically rich, massive star forming region. Several ground-based spectral line surveys have been made, but due to the absorption by water and oxygen, the terrestrial atmosphere is completely opaque at frequencies around 487 and 557 GHz. To cover these frequencies we used the Odin satellite to perform a spectral line survey in the frequency ranges 486-492 GHz and 541-577 GHz, filling the gaps between previous spectral scans. Odin's high main beam efficiency, $\eta_{{\rm mb}}$ = 0.9, and observations performed outside the atmosphere make our intensity scale very well determined.Results.We observed 280 spectral lines from 38 molecules including isotopologues, and, in addition, 64 unidentified lines. A few U-lines have interesting frequency coincidences such as ND and the anion SH-. The beam-averaged emission is dominated by CO, H2O, SO2, SO, 13CO and CH3OH. Species with the largest number of lines are CH3OH, (CH3)2O, SO2, 13CH3OH, CH3CN and NO. Six water lines are detected including the ground state rotational transition 11,0-10,1 of o-H2O, its isotopologues o-H218O and o-H217O, the Hot Core tracing p-H2O transition 62,4-71,7, and the 20, 2-11,1 transition of HDO. Other lines of special interest are the 10-0$_$ transition of NH3 and its isotopologue 15NH3. Isotopologue abundance ratios of D/H, 12C/13C, 32S/34S, 34S/33S, and 18O/17O are estimated. The temperatures, column densities and abundances in the various subregions are estimated, and we find very high gas-phase abundances of H2O, NH3, SO2, SO, NO, and CH3OH. A comparison with the ice inventory of ISO sheds new light on the origin of the abundant gas-phase molecules.
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| 32. |
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| 33. |
- Persson, Per, 1968, et al.
(författare)
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Technical Debt in the Municipality Sector - The Missing Link with Citizens and Silofication
- 2023
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Ingår i: The 14th Scandinavian Conference of Information Systems. - : Association for Information Systems.
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Konferensbidrag (refereegranskat)abstract
- Public sector organizations suffer from high levels of technical debt (TD). TD leaves digital infrastructures in a derelict state, making digital transformations costly and risky. Though there is growing research about TD, most studies focus on private businesses, and there is a lack of research about TD in the public sector. In this study, we conduct a case study examining the TD in a Swedish municipality, analyzing archival data such as project reports, municipality blog posts on digital transformation, and goals to improve citizen experience. We focus on four information systems that support permit application processes. Analysis results reveal the common TD types, consequences, and possible causes. Departments work in silos, the case manager perspective is prevalent in requirements, and the citizens only have a limited passive role as system users leading to various types of TD and high costs when integrating legacy systems into a coherent IT architecture. By diving deep into the data from a specific forerunner municipality, we identify TD and increase our understanding of how debt influences digital transformation. Results give a stable ground for further research and practice on mitigating the debt.
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| 34. |
- Persson, Per, 1968, et al.
(författare)
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Toward Citizen-Centered Digital Government : Design Principles Guided Legacy System Renewal in A Swedish Municipality
- 2024
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Ingår i: Proceedings of the 57th Hawaii International Conference on System Sciences. - : ScholarSpace. - 1530-1605 .- 2572-6862. - 9780998133171 ; , s. 1963-1972
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Konferensbidrag (refereegranskat)abstract
- Transformation towards a digital government imposes significant demands on the capabilities of legacy infrastructure. We closely followed a Swedish municipality that designed and implemented a solution to improve the building permit application process with an aim to improve citizen service. We developed six design principles (DPs): availability, timeliness, actionability, transparency, personalization, and generalizability. These DPs guide the solution design and provide a seamless application experience for citizens and business owners. We also discuss the reasoning behind the design choices and the implications of the solution. The artifact encompasses understanding citizens’ needs, identifying constraints of the legacy systems, formulating design principles, and developing architectural designs. However, addressing the social aspects of legacy systems, such as organizational culture change, necessitates additional steps, and is worth investigation in future studies.
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| 35. |
- Persson, Per, 1968, et al.
(författare)
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Öppen källkod i offentlig digitalisering: Analys av Open ePlatform ur ett öppet källkodsperspektiv
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Digitalisering i offentlig sektor har i huvudsak realiserats genom etablering av vad som benämns ”etjänster”, det vill säga digitala versioner av existerande tjänster med varierande sofistikation. Den kommunala sektorn har till stor del byggt mycket av sitt existerande e-tjänsteutbud på en gemensam plattform, Open ePlatform. Givet avsaknaden av tillräcklig styrning har denna plattform ej underhållits och utvecklats i linje med teknikens utveckling, varvid den nu i praktiken är att betrakta som en proprietär produkt och inte den lösning i öppen källkod som var ambitionen. Rapporten beskriver möjligheterna och kraven associerade med tilltagande användning av öppen källkod i offentlig digitalisering, samt de brister som föreligger i Open ePlatform. Rapporten föreslår insatser för att dels kortsiktigt säkerställa kontinuiteten i den befintliga plattformen och dels långsiktigt säkra fortsatt ändamålsenlig digitalisering bland kommuner genom öppen källkod.
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| 36. |
- Rode, Julia, 1992-, et al.
(författare)
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Multi-Strain Probiotic Mixture Affects Brain Morphology and Resting State Brain Function in Healthy Subjects : An RCT
- 2022
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Ingår i: Cells. - : MDPI. - 2073-4409. ; 11:18
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Tidskriftsartikel (refereegranskat)abstract
- Probiotics can alter brain function via the gut-brain axis. We investigated the effect of a probiotic mixture containing Bifidobacterium longum, Lactobacillus helveticus and Lactiplantibacillus plantarum. In a randomized, placebo-controlled, double-blinded crossover design, 22 healthy subjects (6 m/16 f; 24.2 ± 3.4 years) underwent four-week intervention periods with probiotics and placebo, separated by a four-week washout period. Voxel-based morphometry indicated that the probiotic intervention affected the gray matter volume of a cluster covering the left supramarginal gyrus and superior parietal lobule (p < 0.0001), two regions that were also among those with an altered resting state functional connectivity. Probiotic intervention resulted in significant (FDR < 0.05) functional connectivity changes between regions within the default mode, salience, frontoparietal as well as the language network and several regions located outside these networks. Psychological symptoms trended towards improvement after probiotic intervention, i.e., the total score of the Hospital Anxiety and Depression Scale (p = 0.056) and its depression sub-score (p = 0.093), as well as sleep patterns (p = 0.058). The probiotic intervention evoked distinct changes in brain morphology and resting state brain function alongside slight improvements of psycho(bio)logical markers of the gut-brain axis. The combination of those parameters may provide new insights into the modes of action by which gut microbiota can affect gut-brain communication and hence brain function.
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| 37. |
- Rode, Julia, 1992-, et al.
(författare)
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Probiotic Mixture Containing Lactobacillus helveticus, Bifidobacterium longum and Lactiplantibacillus plantarum Affects Brain Responses Toward an Emotional Task in Healthy Subjects : A Randomized Clinical Trial
- 2022
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Ingår i: Frontiers in nutrition. - : Frontiers Media S.A.. - 2296-861X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Background: Evidence from preclinical studies suggests that probiotics affect brain function via the microbiome-gut-brain axis, but evidence in humans remains limited.Objective: The present proof-of-concept study investigated if a probiotic product containing a mixture of Bifidobacterium longum R0175, Lactobacillus helveticus R0052 and Lactiplantibacillus plantarum R1012 (in total 3 × 109 CFU/day) affected functional brain responses in healthy subjects during an emotional attention task.Design: In this double-blinded, randomized, placebo-controlled crossover study (Clinicaltrials.gov, NCT03615651), 22 healthy subjects (24.2 ± 3.4 years, 6 males/16 females) were exposed to a probiotic intervention and a placebo for 4 weeks each, separated by a 4-week washout period. Subjects underwent functional magnetic resonance imaging while performing an emotional attention task after each intervention period. Differential brain activity and functional connectivity were assessed.Results: Altered brain responses were observed in brain regions implicated in emotional, cognitive and face processing. Increased activation in the orbitofrontal cortex, a region that receives extensive sensory input and in turn projects to regions implicated in emotional processing, was found after probiotic intervention compared to placebo using a cluster-based analysis of functionally defined areas. Significantly reduced task-related functional connectivity was observed after the probiotic intervention compared to placebo. Fecal microbiota composition was not majorly affected by probiotic intervention.Conclusion: The probiotic intervention resulted in subtly altered brain activity and functional connectivity in healthy subjects performing an emotional task without major effects on the fecal microbiota composition. This indicates that the probiotic effects occurred via microbe-host interactions on other levels. Further analysis of signaling molecules could give possible insights into the modes of action of the probiotic intervention on the gut-brain axis in general and brain function specifically. The presented findings further support the growing consensus that probiotic supplementation influences brain function and emotional regulation, even in healthy subjects. Future studies including patients with altered emotional processing, such as anxiety or depression symptoms are of great interest.Clinical Trial Registration: [http://clinicaltrials.gov/], identifier [NCT03615651].
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| 38. |
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| 39. |
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| 40. |
- Serban, Alexandra, 1988-, et al.
(författare)
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Magnetron Sputter Epitaxy of High-Quality GaN Nanorods on Functional and Cost-Effective Templates/Substrates
- 2017
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Ingår i: Energies. - Basel, Switzerland : MDPI AG. - 1996-1073. ; 10:9
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the versatility of magnetron sputter epitaxy by achieving high-quality GaN nanorods on different substrate/template combinations, specifically Si, SiC, TiN/Si, ZrB2/Si, ZrB2/SiC, Mo, and Ti. Growth temperature was optimized on Si, TiN/Si, and ZrB2/Si, resulting in increased nanorod aspect ratio with temperature. All nanorods exhibit high purity and quality, proved by the strong bandedge emission recorded with cathodoluminescence spectroscopy at room temperature as well as transmission electron microscopy. These substrates/templates are affordable compared to many conventional substrates, and the direct deposition onto them eliminates cumbersome post-processing steps in device fabrication. Thus, magnetron sputter epitaxy offers an attractive alternative for simple and affordable fabrication in optoelectronic device technology.
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| 41. |
- Sivencrona, Håkan, 1968, et al.
(författare)
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Heavy-ion Fault Injection in the Time-triggered Communication Protocol
- 2003
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Ingår i: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. - 9783540202240 ; 2847, s. 69-80
-
Konferensbidrag (refereegranskat)abstract
- In dependable distributed systems, the communication link is a critical component with strict dependability requirements. The Time-Triggered Protocol (TTP/C) was developed to meet these requirements. To validate this design, one node in a TTP/C cluster was injected with faults using heavy-ions. It was a prototype implementation and cluster sizes of four and five nodes were tested. The experimental results show that arbitrary faults in one node can cause inconsistencies in the cluster and jeopardize the operation of correctly working nodes and the whole cluster. Further, the system’s vulnerability to arbitrary failures in single nodes for a cluster with a broadcast bus is shown. Experiments with varying cluster sizes indicate a relationship between cluster size and system vulnerability thus it seems to be important to further analyze if and why cluster sizes need to be taken into account when validating distributed systems. The described inconsistencies resulted from asymmetric value faults, asymmetric timing faults or arbitrary single node failures.
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| 42. |
- Sjöström, Jesper, Professor, 1974-, et al.
(författare)
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Knowledge contributions from different school subjects to cross-curricular didactics for Bildung and sustainability
- 2024
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Ingår i: Studies in Subject Didactics. - 1799-960X. ; 25, s. 66-91
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Tidskriftsartikel (refereegranskat)abstract
- In the context of humanistic Bildung-centred Didaktik, the educational potential of different school subjects is emphasized. But how can different school subjects collectively contribute to the ‘cultivation-of-human-powers’ and Bildung with a focus on sustainability? In this article, seven different school subjects are compared. Eleven teacher educators from Malmö University, Sweden, have written scholarly about the roles of their respective school subjects for Bildung and sustainability. Drawing from the texts related to the seven school subjects – geography, mathematics, physical education and health, religious education, science for citizenship, Swedish as a second language, and visual arts – a comparative analysis was conducted. The primary focus was to understand the unique characteristics of each school subject, explore their epistemic differences, and discern their potential roles in fostering cross-curricular didactics for Bildung and sustainability. It is shown that the different school subjects collectively provide complementary contributions to contemporary Bildung and climate change literacy.
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| 43. |
- Sörstedt, Erik, 1980-, et al.
(författare)
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Computed tomographic colonography : Comparison of two workstations
- 2005
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Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 46:7, s. 671-678
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To compare two commercially available computed tomography (CT) colonography systems with respect to interobserver variability, the influence of level of expertise, and the gradual reduction of reviewing time for each system. Material and Methods: Two residents and two radiologists using Siemens CTAPP Colography software and Viatronix V3DColon software reviewed supine and prone CT acquisitions from 24 patients in a primary 3D endoluminal view. The observers graded each case with respect to technical quality and diagnostic value, assessed the presence of pathology, and indicated the time spent on the viewing. Results: Significant differences were found in technical quality ( P <0.001) and diagnostic value ( P <0.001) depending on which system was used, with higher scores for the Viatronix software. The agreement between specialists tended to be higher than that between residents (κ = 0.63 (0.30-0.95) vs. κ = 0.51 (0.21-0.81)), and the residents gave significantly ( P <0.001) higher scores of technical quality. However, the level of expertise had no significant impact on the assessments. We noted extensive variability in pathological lesions found by the different observers. The number of findings did not differ between workstations, but the viewers tended to report larger polyp sizes with the Viatronix software. The time needed for viewing decreased significantly from the first to the last examination viewed by each observer. Conclusion: Both the evaluated systems present trustworthy images of the human colon, but in a primary 3D setting the Viatronix software is favored owing to the userfriendly interface, higher experienced technical quality, and better diagnostic value. © 2005 Taylor & Francis.
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| 44. |
- Ueda, Peter, et al.
(författare)
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External Validation of the DAPT Score in a Nationwide Population
- 2018
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Ingår i: Journal of the American College of Cardiology. - : ELSEVIER SCIENCE INC. - 0735-1097 .- 1558-3597. ; 72:10, s. 1069-1078
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND The dual antiplatelet therapy (DAPT) score guides decisions on DAPT duration after coronary stenting by simultaneously predicting ischemic and bleeding risk. OBJECTIVES This study sought to assess the performance of the DAPT score in a nationwide real-world population. METHODS The study used register data in Sweden (2006 to 2014) and followed 41,101 patients who had undergone 12 months of event-free DAPT, from months 12 to 30 after stenting. Risk of myocardial infarction (MI) or stent thrombosis, major adverse cardiovascular and cerebrovascular events (MACCE) (MI, stroke, and all-cause death), and fatal or major bleeding were compared according to DAPT score. RESULTS The score had a discrimination of 0.58 (95% confidence interval [CI]: 0.56 to 0.60) for MI or stent thrombosis, 0.54 (95% CI: 0.53 to 0.55) for MACCE, and 0.49 (95% CI: 0.45 to 0.53) for fatal or major bleeding. Risk of MI or stent thrombosis was significantly increased at scores of >= 3 while MACCE risk followed a J-shaped pattern and increased at scores of >= 4. Absolute differences in fatal or major bleeding risk were small between scores. Event rates of ischemic and bleeding outcomes in patients with high (>= 2) and low (< 2) scores differed compared to the DAPT Study from which the score was derived; fatal or major bleeding rates were approximately one-half of those in the placebo arm of the DAPT Study. CONCLUSIONS In a nationwide population, the DAPT score did not adequately discriminate ischemic and bleeding risk, the relationship between score and ischemic risk did not correspond to the suggested decision rule for extended DAPT, and risk of bleeding was lower compared with the DAPT Study. The score and its decision rule may not be generalizable to real-world populations.
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| 45. |
- Vestergren, Johan, 1968-
(författare)
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Analysis and speciation of organic phosphorus in environmental matrices : Development of methods to improve 31P NMR analysis
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Phosphorus (P) is an essential element for life on our planet. It is central in numerous biochemical processes in terrestrial and aqueous ecosystems including food production; and it is the primary growth-limiting nutrient in some of the world’s biomes. The main source of P for use as agricultural fertilizer is mining of non-renewable mineral phosphate. In terrestrial ecosystems the main source is soil P, where the largest fraction is organic P, composed of many species with widely differing properties. This fraction controls the utilization of P by plants and microorganisms and influences ecosystem development and productivity. However, there is only scarce knowledge about the molecular composition of the organic P pool, about the processes controlling its bioavailability, and about its changes as soils develop. Therefore, the aim of this thesis was to develop robust solution- and solid-state 31P nuclear magnetic resonance spectroscopy (NMR) methods to provide molecular information about speciation of the organic P pool, and to study its dynamics in boreal and tropical soils. By studying humus soils of a groundwater recharge/discharge productivity gradient in a Fennoscandian boreal forest by solution- and solid-state NMR, it was found that P speciation changed with productivity. In particular, the level of orthophosphate diesters decreased with increasing productivity while mono-esters such as inositol phosphates increased. Because the use of solution NMR on conventional NaOH/EDTA extracts of soils was limited due to severe line broadening caused by the presence of paramagnetic metal ions, a new extraction method was developed and validated. Based on the removal of these paramagnetic impurities by sulfide precipitation, a dramatic decrease in NMR linewidths was obtained, allowing for the first time to apply modern multi-dimensional solution NMR techniques to soil extracts. Identification of individual soil P-species, and tracking changes in the organic P pools during soil development provided information for connecting P-speciation to bioavailability and ecosystem properties. Using this NMR approach we studied the transformation of organic P in humus soils along a chronosequence (7800 years) in Northern Sweden. While total P varied little, the composition of the soil P pool changed particularly among young sites, where also the largest shift in the composition of the plant community and of soil microorganisms was observed. Very old soils, such as found Africa, are thought to strongly adsorb P, limiting plant productivity. I used NMR to study the effect of scattered agroforestry trees on P speciation in two semi-arid tropical woodlands with different soil mineralogy (Burkina Faso). While the total P concentration was low, under the tree canopies higher amounts of P and higher diversity of P-species were found, presumably reflecting higher microbial activity.
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