| 1. |
- Vikström, Lars, et al.
(författare)
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Strength and deformation behaviour of snow and snow structures : field and laboratory measurements at Icehotel Jukkasjärvi, Winter 2000 - 2001
- 2002
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Density measurements, unconfined compression tests, creep tests, beam tests, and measurements of deformations were performed on snow and snow structures that formed the Icehotel during the winter 2000/2001. Results from the unconfined compression tests and creep tests showed that: At -5ºC unconfined compression strength was 0,598 MPa with a snow density of 532 kg/m3. Axial viscosity was 3,23·106 MPa-s and compactive viscosity was 5,24·106 MPa-s with a snow density of 524 kg/m3. At -10ºC unconfined compression strength was 0,681 MPa with a snow density of 558 kg/m3. Axial viscosity was 1,92·106 MPa-s and compactive viscosity was 1,38·106 MPa-s with a snow density of 518 kg/m3. At -11ºC unconfined compression strength was 0,879 MPa with a snow density of 550 kg/m3. Axial viscosity was 2,16·106 MPa-s and compactive viscosity was 2,79·106 MPa-s with a snow density of 470 kg/m3. Beam tests were performed on snow from a pile of artificially made snow. This type of snow was used to construct the arcs of the Icehotel. Results from the beam tests showed that the snow had a mean density of 510 kg/m3 and that Young's modulus E had a mean value of 335 MPa. At failure mean value of maximum tensile- and compression stress was 0,375 MPa and mean value of maximum shear stress was 0,039 MPa. During the winter 2000/2001 deformations of the church building were measured. Results show that the apex of the arcs actually rose 4 to 8 cm, though the shape of the arcs changed very little. Comparing results from this investigation with results from earlier investigations made on snow with similar densities showed that: Unconfined compression strength was 20 to 40 percent lower. Axial viscosity was similar in all but one test at -10/-11 ºC. Axial viscosity was in all tests higher at -5 ºC. Compactive viscosity was higher in all tests. Results from the beam tests regarding Young's modulus values and tensile strength showed similar results.
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| 2. |
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| 6. |
- Fiskesund, Roland, et al.
(författare)
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Low levels of antibodies against phosphorylcholine predict development of stroke in a population-based study from northern Sweden
- 2010
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Ingår i: Stroke. - 0039-2499 .- 1524-4628. ; 41:4, s. 607-612
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Natural immunoglobulin M antibodies specific for phosphorylcholine (anti-PC) have been implicated in atherosclerosis. We have shown previously that high levels of anti-PC predict a slower progression of atherosclerosis in humans and that low levels of anti-PC are associated with higher risk for cardiovascular disease. Here we determine the association between anti-PC and the incidence of stroke. METHODS: Using a nested case control study design, we examined 227 incident cases (125 men and 102 women) of first-time stroke and 455 age- and sex-matched controls identified during a 13-year time period (1985 to 1999) within the population-based cohorts of the Västerbotten Intervention Project (VIP) and the World Health Organization Monitoring Trends and Determinants in Cardiovascular Disease (WHO MONICA) project in Northern Sweden. Odds ratios of stroke with 95% CIs with adjustments for age, gender, smoking, serum cholesterol, diabetes, body mass index, and blood pressure were determined. Anti-PC levels were measured using ELISA. RESULTS: A significant association between low levels of anti-PC at baseline and incident stroke was seen for the whole group of anti-PC levels below the 30th percentile (multivariately adjusted odds ratio, 1.62; CI, 1.11 to 2.35). Analyses of gender-specific associations indicated fairly strong associations for females, especially at the lowest 30th percentile (multivariately adjusted odds ratio, 2.65; CI, 1.41 to 4.95). No associations were noted for men. CONCLUSION: Low anti-PC is a novel independent risk marker for development of stroke. Measurements of anti-PC could be used to identify immunodeficient subjects at an increased risk for stroke. The possibility that such subjects might be targets for novel modes of treatment such as immunotherapies deserves further investigation.
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| 7. |
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| 8. |
- Haglund, Lars, et al.
(författare)
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Karlstadsstudenter om studier och studentliv
- 2003
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Rapport (refereegranskat)abstract
- Denna rapport, Karlstadstudenter om studier och studentliv, sammanställer information om studenters syn på Karlstads universitet som samlats i flera olika undersökningar. Under 90-talet genomfördes en longitudinell studie kring studenters upplevelser av utbildning och studiemiljö i syfte att kartlägga studenternas syn på kvaliteten i utbildningen vid den dåvarande högskolan i Karlstad. Under hösten 1999 och våren 2000 genomfördes Studentbarometern, en omfattande undersökning för att kartlägga attityder till utbildningen vid det nybildade universitetet. Slutligen har från våren 2000 teminsvisa enkätundersökningar gjorts för att följa kvalitetsutvecklingen vid Karlstads universitet.Information från undersökningarna har i rapporten analyserats ur ett marknadsföringsperspektiv. Slutsatser från undersökningarna skall förhoppningsvis kunna utgöra en grund för kvalitetsutveckling och marknadsföring av Karlstads universitet.
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| 9. |
- Hylander, Lars D., et al.
(författare)
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Fish mercury increase in Lago Manso, a new hydroelectric reservoir in tropical Brazil
- 2006
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 81:2, s. 155-166
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Tidskriftsartikel (refereegranskat)abstract
- It has been frequently demonstrated that mercury (Hg) concentrations in fish rise in newly constructed hydroelectric reservoirs in the Northern Hemisphere. In the present work, we studied whether similar effects take place also in a tropical upland reservoir during impoundment and discuss possible causes and implications. Total Hg concentrations in fish and several soil and water parameters were determined before and after flooding at Rio Manso hydroelectric power plant in western Brazil. The Hg concentrations in soil and sediment were within the background levels in the region (22-35 ng g(-1) dry weight). There was a strong positive correlation between Hg and carbon and sulphur in sediment. Predatory fish had total Hg concentrations ranging between 70 and 210 ng g(-1) f.w. 7 years before flooding and between 72 and 755 ng g(-1) f.w. during flooding, but increased to between 216 and 938 ng g(-1) f.w. in the piscivorous and carnivorous species Pseudoplatystoma fasciatum, cachara, and Salminus brasiliensis, dourado, 3 years after flooding. At the same time, concentrations of organic carbon in the water increased and oxygen concentrations decreased, indicating increased decomposition and anoxia as contributing to the increased Hg concentrations in fish. The present fish Hg concentrations in commonly consumed piscivorous species are a threat to the health of the population dependent on fishing in the dam and downstream river for sustenance. Mercury exposure can be reduced by following fish consumption recommendations until fish Hg concentrations decrease to a safe level.
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| 14. |
- Lintzén, Nina
(författare)
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Mechanical properties of artificial snow
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mechanical properties of snow have been a subject of research since the mid-20th century. Theresearch done is based on natural snow. During the last decades the winter business industryhas been growing and also the interest for constructing buildings and artwork of snow. Suchconstructions are generally built using artificial snow, i.e. snow produced by snow guns. Up tothe present constructions of snow are designed based on knowledge by experience. Only minorscientific studies on artificial snow and its properties has been published. Hence it is ofimportance to investigate material properties for artificial snow.A survey of current state of the art knowledge of properties for natural snow was done andbasic material properties for different qualities of artificial snow were investigated. Strengthand deformation properties for artificial snow were evaluated through uniaxial compressivetests where cylindrical test specimens were subjected to different constant deformation rates.The results show that artificial snow at low deformation rates will have a plastic deformationbehavior where the initial deformation will cause a hardening of the snow structure. At higherdeformation rates brittle failure may occur. For artificial snow with a homogeneous and finegrained structure the deformation behavior was found to change from plasticity to brittleness ata certain critical deformation rate. Artificial snow with coarse grained structure was found to bebrittle giving unstructured results independent of the load level.Four point loading was applied on beams of artificial snow to study creep deformation, bendingstrength and to determine the ultimate load for the different snow qualities. The results showedcoarse grained artificial snow underwent relatively small creep deformations. Both the creepbehavior and the ultimate strength varied randomly at the same applied load. Large plasticdeformations were observed with the fine grained artificial without any failure of the beams.The ultimate load was relatively high and repeatable results were achieved for all test.Previous presumptions that coarse grained artificial snow with high density would have highstrength and were not confirmed by the experiments performed on different qualities ofartificial snow. The performed tests indicate that fine grained artificial snow of lower densityhave more predictable strength properties of equally high or higher magnitude as for coarsegrained artificial snow. The plastic deformations were however higher for the fine grainedartificial snow. High deformations are not favorable for structures which should maintain theshape during the winter season. When designing constructions of snow both strength anddeformation properties should be taken into account.
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| 15. |
- Lundberg, Angela, et al.
(författare)
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Assessment by project work in snow engineering
- 2003
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Ingår i: European Journal of Engineering Education. - : Informa UK Limited. - 0304-3797 .- 1469-5898. ; 28:1, s. 7-16
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Tidskriftsartikel (refereegranskat)abstract
- Assessment in the form of a large project and field- and laboratory work was shown to be successful when applied to a course in snow engineering for university students with various backgrounds. The course was interdisciplinary, with teachers representing three different engineering disciplines. The project work was assessed by a report, a short oral presentation and an optional presentation such as a home page, a poster or a physical model. The students experienced that they had learned more with this assessment strategy than from courses with a final written exam. Peer evaluation of the relative contributions to the project work was applied and was appreciated by the students. The experiences of practical engineering tasks during the project work were also appreciated.
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| 16. |
- Lundberg, Lars, et al.
(författare)
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Performance indicators for prehospital command and control developed for civilian use tested in a military training setting : a pilot study
- 2008
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Ingår i: Journal of the Royal Army Medical Corps. - : Royal Army Medical Corps. - 0035-8665. ; 154:4, s. 236-238
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The aim of this study was to determine if a set of performance indicators for command and control (C2) primarily developed for civilian use could be applied also to a military training context as well. Method: The initial decision-making in the on-scene medical management in a multinational military medical evacuation exercise in Afghanistan was studied, using this set of indicators. Results: Two performance indicators were appropriate to this setting. Of the nine applicable indicators, the standards set for civilian use were met in four, in three other they were not met, and there was a lack of documentation in two indicators. Conclusion: Measurable performance indicators for prehospital command and control were to some extent found to be applicable also to a military environment. Future developments may make it possible for the concept of measuring results using civilian performance indicators to become a quality control tool in a military setting.
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| 17. |
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| 18. |
- Marklund, Stefan, et al.
(författare)
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Cold Climate Research at Wasa
- 1990
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Ingår i: Swedish Antarctic research programme. - Stockholm : Swedish Polar Research Secretariat. - 9197076929 ; , s. 42-46
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Bokkapitel (populärvet., debatt m.m.)
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| 19. |
- Nilsson, Martin, 1981-
(författare)
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Essays on Health Shocks and Social Insurance
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists of four self-contained essays.Essay 1 (with Petter Lundborg and Johan Vikström): This paper provides new evidence on heterogeneity in the impact of health shocks by using register-based data on the entire population of Swedish workers. We formulate a Difference-in-Difference design, where we compare the change in labor earnings across matched high and low-educated workers who experience the same type of health shocks. This design takes away the requirement to define control groups of workers not suffering from health shocks. Our results suggest large heterogeneity in the effects, where low-educated individuals suffer relatively more from a given health shock. These results holds across different types of health shocks and becomes more pronounced by age. Low-educated workers are also more likely to leave the labor force and take up disability insurance, sickness insurance, and unemployment benefits following a health shock. Our results suggest that socioeconomic heterogeneity in the effect of health shocks offers one explanation to how the socioeconomic gradient in health arises.Essay 2: Reductions in SI replacement levels have been a widely used instrument to lower sickness absence rates. The idea is that increasing the direct cost of absence would lower the absence rate. This paper explores a reform of the compulsory Swedish SI scheme. The reform reduced the replacement level from 90 percent of foregone earnings to 65 percent for the first 3 days of a sickness absence spell and to 80 percent for days 4 - 90. From day 91 onwards the rate remained at 90 percent. In this paper, I show that the reform had both a direct and an indirect effect on sickness absence behavior. Using detailed register data on the complete account of all sickness absence spells during the period, I am able to identify and estimate the indirect effect on absence-to-work transitions. I find that the indirect effect significantly reduces the probability to end an absence spell, creating a locking-in effect in sickness absence.Essay 3 (with Per Johansson): Sweden has obligatory sickness and disability insurance which is both financed and administered by the government. In order to receive sickness benefits, insured individuals must have certificates issued by a medical doctor. Since health care is administered at the county level, this means that monitoring is, to some extent, decentralized at a lower jurisdictional level than the funding and governance of the insurance. This paper studies one consequence of such decentralization: the effect on individual sickness absence when such certificates are not approved by the Swedish Social Insurance Agency (SIA) and are instead re-remitted to the doctor for completion and, potential, approval by the SIA. We find that this re-remission increases the length of sickness absence spells by an average of 30 percent. Given that added resources improve the quality of the patients' medical certificates, directed intergovernmental grants from the state to the counties would be cost saving.Essay 4: Injuries due to road accidents represent a large welfare loss to society. Damage costs include a variety of expenses related to, medical treatment, material and immaterial damage, law enforcement, production loss, and loss of time. Using use detailed Swedish longitudinal administrative data, and taking an incidence-based approach this paper provides an estimate of lost productivity not restricted to prevalence and the tenuous assumption that accidents are random. Total lost productivity is estimated to be 900 million SEK (€ 100 M), 408 million SEK (€ 45 M) of which is the burden on public insurance. The study also finds that there is a clear negative selection for road accidents. Accident victims are, on average, less educated, have a lower employment rate, and lower labor earnings than those who where not involved in a road accident. If this selection is not taken into account in the calculations, the cost will be overestimated.
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| 20. |
- Vikström, Anna, et al.
(författare)
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Coding of procedures documented by general practitioners in Swedish primary care - an explorative study using two procedure coding systems.
- 2012
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Ingår i: BMC family practice. - : Springer Science and Business Media LLC. - 1471-2296. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: BACKGROUND: Procedures documented by general practitioners in primary care have not been studied in relation to procedure coding systems. We aimed to describe procedures documented by Swedish general practitioners in electronic patient records and to compare them to the Swedish Classification of Health Interventions (KVA) and SNOMED CT. METHODS: Procedures in 200 record entries were identified, coded, assessed in relation to two procedure coding systems and analysed. RESULTS: 417 procedures found in the 200 electronic patient record entries were coded with 36 different Classification of Health Interventions categories and 148 different SNOMED CT concepts. 22.8% of the procedures could not be coded with any Classification of Health Interventions category and 4.3% could not be coded with any SNOMED CT concept. 206 procedure-concept/category pairs were assessed as a complete match in SNOMED CT compared to 10 in the Classification of Health Interventions. CONCLUSIONS: Procedures documented by general practitioners were present in nearly all electronic patient record entries. Almost all procedures could be coded using SNOMED-CT. Classification of Health Interventions covered the procedures to a lesser extent and with a much lower degree of concordance. SNOMED CT is a more flexible terminology system that can be used for different purposes for procedure coding in primary care.
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| 23. |
- Vikström, Lotta, 1971-, et al.
(författare)
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Marriage Patterns in Swedish Cities 1840-1990
- 2004
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Ingår i: Living in the City (14th-20th Centuries). - Rome : La Sapienza, University of Rome. - 8887242356 ; , s. 203-236
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 24. |
- Vikström, Lars
(författare)
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Uppmätta och beräknade tjällyftningar och tjäldjup i jord : en analys av ingångsparametrarnas betydelse för beräkningsresultatet
- 1999
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Målet med arbetet som ligger till grund för licentiatuppsatsen har varit att bestämma behovet av och omfattningen på fält- och laboratorieundersökningar för att erhålla tillförlitliga resultat från beräkningar med programmet Pc-heave. Utgångspunkten har varit att studera om man enbart med en enklare fält- och laboratorieundersökningar kan erhålla ingångsparametrar som ger tillräcklig noggrannhet vid predikteringen av tjällyftning och tjälnedträngning i en jord med hjälp av programmet Pc-heave. Syftet har varit att beräkningen skall vara en prognos och utföras utan att i efterhand behöva anpassa parametrarna för att uppnå överensstämmelse mellan beräknade och uppmätta värden på tjälnedträngning och tjällyftning. Med anpassning av sådana parametrar som, mängd ofruset vatten och permeabilitet, utifrån en kortare tids, en månads, observationer i inledningen av tjälningsperioden erhåller man god överensstämmelse mellan beräknade och uppmätta värden på tjällyftning, islinsernas läge och mäktighet och tjälnedträngningen. Islinsernas läge och mäktighet i den frusna jorden har detekterats med hjälp av röntgenfotografering av upptagna borrkärnor. Ingångsparametrar valda utifrån enklare undersökningar av typen kornfördelning, densitet, vattenkvot eller ytterligare parametrar bland annat ofrusetvatteninnehåll och permeabilitet bestämda i laboratorium ger däremot sämre resultat.
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| 25. |
- Vikström, Maria, et al.
(författare)
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Dagvattendammars avskiljningsförmåga – påverkande faktorer och metodik för bedömning
- 2004
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten beskriver hur numeriska modeller, främst MIKE 21, använts för att ta fram en generell beräkningsmetodik för bedömning av dagvattendammars avskiljningsförmåga. En modellbaserad fallstudie har genomförts för att studera de påverkansfaktorer som styr avskiljningen i en dagvattendamm.
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| 26. |
- Åberg, Anna, et al.
(författare)
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Helicobacter pylori adapts to chronic infection and gastric disease via ph-responsive baba-mediated adherence
- 2017
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Ingår i: Cell Host and Microbe. - : Elsevier BV. - 1931-3128 .- 1934-6069. ; 21:3, s. 376-389
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Tidskriftsartikel (refereegranskat)abstract
- The BabA adhesin mediates high-affinity binding of Helicobacter pylori to the ABO blood group antigen-glycosylated gastric mucosa. Here we show that BabA is acid responsive-binding is reduced at low pH and restored by acid neutralization. Acid responsiveness differs among strains; often correlates with different intragastric regions and evolves during chronic infection and disease progression; and depends on pH sensor sequences in BabA and on pH reversible formation of high-affinity binding BabA multimers. We propose that BabA's extraordinary reversible acid responsiveness enables tight mucosal bacterial adherence while also allowing an effective escape from epithelial cells and mucus that are shed into the acidic bactericidal lumen and that bio-selection and changes in BabA binding properties through mutation and recombination with babA-related genes are selected by differences among individuals and by changes in gastric acidity over time. These processes generate diverse H. pylori subpopulations, in which BabA's adaptive evolution contributes to H. pylori persistence and overt gastric disease.
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