| 1. |
- Roselli, Carolina, et al.
(författare)
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Multi-ethnic genome-wide association study for atrial fibrillation
- 2018
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 50:9, s. 1225-1233
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Tidskriftsartikel (refereegranskat)abstract
- Atrial fibrillation (AF) affects more than 33 million individuals worldwide(1) and has a complex heritability(2). We conducted the largest meta-analysis of genome-wide association studies (GWAS) for AF to date, consisting of more than half a million individuals, including 65,446 with AF. In total, we identified 97 loci significantly associated with AF, including 67 that were novel in a combined-ancestry analysis, and 3 that were novel in a European-specific analysis. We sought to identify AF-associated genes at the GWAS loci by performing RNA-sequencing and expression quantitative trait locus analyses in 101 left atrial samples, the most relevant tissue for AF. We also performed transcriptome-wide analyses that identified 57 AF-associated genes, 42 of which overlap with GWAS loci. The identified loci implicate genes enriched within cardiac developmental, electrophysiological, contractile and structural pathways. These results extend our understanding of the biological pathways underlying AF and may facilitate the development of therapeutics for AF.
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| 2. |
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| 3. |
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| 4. |
- Engström, Hans, et al.
(författare)
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High power laser welding of thick construction steels
- 2000
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Ingår i: Proceedings of the Laser Materials Processing Conference.. - Orlando, Fla : Laser institute of America. - 0912035609 ; , s. A42-A51
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Konferensbidrag (refereegranskat)abstract
- Experimental results are reported from an investigation to develop a laser welding technique for welding thick (greater than 5 mm) construction steels. The construction steels investigated were: three grades of high strength Domex steels (6-8 mm thickness), high strength Weldox 500 (6 mm thickness) and wear resistant Hardox 400 (10-15 mm thickness). The following tests were performed to evaluate the laser welded joints: visual inspection, radiographic examination, macrophotographs, hardness, bending and tensile tests, and impact toughness tests. Three types of joint were studied: autogenous butt joints, filler welded butt joints and corner joints. Design opportunities for this process are also discussed.
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| 5. |
- Engström, Hans, et al.
(författare)
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Laser welding of thick structural steels
- 2001
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Ingår i: 8th NOLAMP, Proceedings. - Lyngby : Technical University of Denmark. - 8790855329 ; , s. 93-104
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Konferensbidrag (refereegranskat)abstract
- Experiments to determine process conditions for laser welding of thick structural steels are reported. Materials tested were: Domex 355, 460, 600 and 390, high strength, cold forming, microalloyed steels, 8-12 mm thickness; Weldox 960 high strength structural steel, 10 mm thickness; and Hardox 400 wear resistant steel, 10-15 mm thickness. Tests were performed using 12 and 17 kW lasers, with milled or laser cut edge preparation, various butt joint preparations, using autogenous and filler wire welding. Weld shape, microstructure and hardness, torsion fatigue strength, process envelopes for avoidance of solidification defects and laser optics requirements are reported.
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| 6. |
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| 7. |
- Engström, Hans, et al.
(författare)
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Utveckling av lasersvetsteknik för detaljer i tjockt konstruktionsstål : ett projekt inom RACER - ett industristyrt utvecklingsprogram för laserbearbetning av abrasiv vattenstråleskärning
- 2000
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Svetsning med högeffektslaser erbjuder många fördelar jämfört med konventionella svetsmetoder; hög svetshastighet, låg eller oftast ingen förbrukning av tillsatsmaterial, lätt automatiserad, mycket hög svetskvalitet och framför allt liten värmepåverkan med liten, vanligen försumbar, formändring av arbetsstycket. CO2-lasrar med uteffekter på 20 kW samt den snabba utvecklingen av högeffekts Nd:YAG-laser kombinerad med fiberoptik erbjuder potentiellt stora utvecklingsmöjligheter för industriell användning inom området svetsning av tjocka material. F&U inom området lasersvetsning av tjock plåt pågår i Europa och är främst riktad mot varvsindustrin. I Sverige har ett initiativ tagits för att introducera tekniken hos tung fordons- och verkstadsindustri. Målet med projektet, som finansierats av NUTEK och deltagande projektpartners från industrin, har varit att vidareutveckla tekniken att lasersvetsa höghållfasta konstruktionsstål och introducera tekniken till i första hand tung fordons- och verkstadsindustri. Projektet har omfattat F&U av lasersvetsning av tjock plåt 8 - 15 mm i hållfasthetsområdet 280 - 960 MPa . Verkstadsindustriföretag och ståltillverkare har aktivt deltagit i projektet. Mekanisk hållfasthetsprovning och metallografiska studier av utförda svetsar har visat på mycket goda resultat i de flesta fall bättre än med konventionella svetsmetoder. Fortsatta försök med svetsade lådbalkar som tidigare provats avseende statisk hållfasthet och utmattningshållfasthet har uppvisat testresultat som överträffar de som svetsats med konventionella metoder. Svetsresultaten visar att lasersvetsning ger produktionsmässiga parameterfönster upp till plåttjocklek = 10 mm för de undersökta stålen. Från 12 mm och uppåt är resultaten hittills inte helt entydiga varför fortsatt utvecklingsarbete krävs för att öka förståelsen hos processen och för att vidareutveckla tekniken.
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| 8. |
- Haghighi, Mona, et al.
(författare)
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A Comparison of Rule-based Analysis with Regression Methods in Understanding the Risk Factors for Study Withdrawal in a Pediatric Study
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Regression models are extensively used in many epidemiological studies to understand the linkage between specific outcomes of interest and their risk factors. However, regression models in general examine the average effects of the risk factors and ignore subgroups with different risk profiles. As a result, interventions are often geared towards the average member of the population, without consideration of the special health needs of different subgroups within the population. This paper demonstrates the value of using rule-based analysis methods that can identify subgroups with heterogeneous risk profiles in a population without imposing assumptions on the subgroups or method. The rules define the risk pattern of subsets of individuals by not only considering the interactions between the risk factors but also their ranges. We compared the rule-based analysis results with the results from a logistic regression model in The Environmental Determinants of Diabetes in the Young (TEDDY) study. Both methods detected a similar suite of risk factors, but the rule-based analysis was superior at detecting multiple interactions between the risk factors that characterize the subgroups. A further investigation of the particular characteristics of each subgroup may detect the special health needs of the subgroup and lead to tailored interventions.
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| 9. |
- Hammaréus, Filip, et al.
(författare)
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Wall shear stress measured with 4D flow CMR correlates with biomarkers of inflammation and collagen synthesis in mild-to-moderate ascending aortic dilation and tricuspid aortic valves
- 2024
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Ingår i: European Heart Journal Cardiovascular Imaging. - : OXFORD UNIV PRESS. - 2047-2404 .- 2047-2412.
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Tidskriftsartikel (refereegranskat)abstract
- Aims Understanding the mechanisms underlying ascending aortic dilation is imperative for refined risk stratification of these patients, particularly among incidentally identified patients, most commonly presenting with tricuspid valves. The aim of this study was to explore associations between ascending aortic haemodynamics, assessed using four-dimensional flow cardiovascular magnetic resonance imaging (4D flow CMR), and circulating biomarkers in aortic dilation. Methods and results Forty-seven cases with aortic dilation (diameter >= 40 mm) and 50 sex-and age-matched controls (diameter < 40 mm), all with tricuspid aortic valves, underwent 4D flow CMR and venous blood sampling. Associations between flow displacement, wall shear stress (WSS), and oscillatory shear index in the ascending aorta derived from 4D flow CMR, and biomarkers including interleukin-6, collagen type I alpha 1 chain, metalloproteinases (MMPs), and inhibitors of MMPs derived from blood plasma, were investigated. Cases with dilation exhibited lower peak systolic WSS, higher flow displacement, and higher mean oscillatory shear index compared with controls without dilation. No significant differences in biomarkers were observed between the groups. Correlations between haemodynamics and biomarkers were observed, particularly between maximum time-averaged WSS and interleukin-6 (r = 0.539, P < 0.001), and maximum oscillatory shear index and collagen type I alpha 1 chain (r = -0.575, P < 0.001 in cases). Conclusion Significant associations were discovered between 4D flow CMR derived whole-cardiac cycle WSS and circulating biomarkers representing inflammation and collagen synthesis, suggesting an intricate interplay between haemodynamics and the processes of inflammation and collagen synthesis in patients with early aortic dilation and tricuspid aortic valves.
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| 10. |
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| 11. |
- Nilsson, Henrik, et al.
(författare)
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Photon pathlength determination based on spatially resolved diffuse reflectance
- 2002
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Ingår i: Journal of Biomedical Optics. - : SPIE-Intl Soc Optical Eng. - 1083-3668 .- 1560-2281. ; 7:3, s. 478-485
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Tidskriftsartikel (refereegranskat)abstract
- A method for the prediction of the average photon pathlength in turbid media has been developed. The method is based on spatially resolved diffuse reflectance with discrete source detector distances up to 2 mm. Light reflectance was simulated using a Monte Carlo technique with a one-layer model utilizing a wide range of optical properties, relevant to human skin. At a source detector separation of 2 mm, the pathlength can vary sixfold due to differences in optical properties. By applying various preprocessing and prediction techniques, the pathlength can be predicted with a root-mean-square error of approximately 5%. Estimation of the photon pathlength can be used, e.g., to remove the influence of optical properties on laser Doppler flowmetry perfusion readings, which are almost linearly related to the average photon pathlength.
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| 12. |
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| 13. |
- Nordeman, Patrik, et al.
(författare)
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C-11 and F-18 Radiolabeling of Tetra- and Pentathiophenes as PET-Ligands for Amyloid Protein Aggregates
- 2016
-
Ingår i: ACS Medicinal Chemistry Letters. - : American Chemical Society (ACS). - 1948-5875. ; 7:4, s. 368-373
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Tidskriftsartikel (refereegranskat)abstract
- Three oligothiophenes were evaluated as PET ligands for the study of local and systemic amyloidosis ex vivo using tissue from patients with amyloid deposits and in vivo using healthy animals and PET-CT. The ex vivo binding studies revealed that all three labeled compounds bound specifically to human amyloid deposits. Specific binding was found in the heart, kidney, liver, and spleen. To verify the specificity of the oligothiophenes toward amyloid deposits, tissue sections with amyloid pathology were stained using the fluorescence exhibited by the compounds and evaluated with multiphoton microscopy. Furthermore, a in vivo monkey PET-CT study showed very low uptake in the brain, pancreas, and heart of the healthy animal indicating low nonspecific binding to healthy tissue. The biological evaluations indicated that this is a promising group of compounds for the visualization of systemic and localized amyloidosis.
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| 14. |
- Osterwalder, S., et al.
(författare)
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Critical Observations of Gaseous Elemental Mercury Air-Sea Exchange
- 2021
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Ingår i: Global Biogeochemical Cycles. - : American Geophysical Union (AGU). - 0886-6236 .- 1944-9224. ; 35:8
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Tidskriftsartikel (refereegranskat)abstract
- Air-sea exchange of gaseous elemental mercury (Hg-0) is not well constrained, even though it is a major component of the global Hg cycle. Lack of Hg-0 flux measurements to validate parameterizations of the Hg-0 transfer velocity contributes to this uncertainty. We measured the Hg-0 flux on the Baltic Sea coast using micrometeorological methods (gradient-based and relaxed eddy accumulation [REA]) and also simulated the flux with a gas exchange model. The coastal waters were typically supersaturated with Hg-0 (mean +/- 1 sigma = 13.5 +/- 3.5 ng m(-3); ca. 10% of total Hg) compared to the atmosphere (1.3 +/- 0.2 ng m(-3)). The Hg-0 flux calculated using the gas exchange model ranged from 0.1-1.3 ng m(-2) h(-1) (10th and 90th percentile) over the course of the campaign (May 10-June 20, 2017) and showed a distinct diel fluctuation. The mean coastal Hg-0 fluxes determined with the two gradient-based approaches and REA were 0.3, 0.5, and 0.6 ng m(-2) h(-1), respectively. In contrast, the mean open sea Hg-0 flux measured with REA was larger (6.3 ng m(-2) h(-1)). The open sea Hg-0 flux indicated a stronger wind speed dependence for the Hg-0 transfer velocity compared to commonly used parameterizations. Although based on a limited data set, we suggest that the wind speed dependence of the Hg-0 transfer velocity is more consistent with gases that have less water solubility than CO2 (e.g., O-2). These pioneering flux measurements using micrometeorological techniques show that more such measurements would improve our understanding of air-sea Hg exchange.
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| 15. |
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| 16. |
- Rutgersson, Anna, 1971-, et al.
(författare)
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Using land-based stations for air–sea interaction studies
- 2020
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Ingår i: Tellus. Series A, Dynamic meteorology and oceanography. - : Informa UK Limited. - 0280-6495 .- 1600-0870. ; 72:1, s. 1-23
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Tidskriftsartikel (refereegranskat)abstract
- In situ measurements representing the marine atmosphere and air-sea interaction are taken at ships, buoys, stationary moorings and land-based towers, where each observation platform has structural restrictions. Air-sea fluxes are often small, and due to the limitations of the sensors, several corrections are applied. Land-based towers are convenient for long-term observations, but one critical aspect is the representativeness of marine conditions. Hence, a careful analysis of the sites and the data is necessary. Based on the concept of flux footprint, we suggest defining flux data from land-based marine micrometeorological sites in categories depending on the type of land influence:1. CAT1: Marine data representing open sea,2. CAT2: Disturbed wave field resulting in physical properties different from open sea conditions and heterogeneity of water properties in the footprint region, and3. CAT3: Mixed land-sea footprint, very heterogeneous conditions and possible active carbon production/consumption.Characterization of data would be beneficial for combined analyses using several sites in coastal and marginal seas and evaluation/comparison of properties and dynamics. Aerosol fluxes are a useful contribution to characterizing a marine micrometeorological field station; for most conditions, they change sign between land and sea sectors. Measured fluxes from the land-based marine station Ostergarnsholm are used as an example of a land-based marine site to evaluate the categories and to present an example of differences between open sea and coastal conditions. At the Ostergarnsholm site the surface drag is larger for CAT2 and CAT3 than for CAT1 when wind speed is below 10m/s. The heat and humidity fluxes show a distinctive distinguished seasonal cycle; latent heat flux is larger for CAT2 and CAT3 compared to CAT1. The flux of carbon dioxide is large from the coastal and land-sea sectors, showing a large seasonal cycle and significant variability (compared to the open sea sector). Aerosol fluxes are partly dominated by sea spray emissions comparable to those observed at other open sea conditions.
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| 17. |
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| 18. |
- Sha, Yongcui, et al.
(författare)
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Diel vertical migration of copepods and its environmental drivers in subtropical Bahamian blue holes
- 2021
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Ingår i: Aquatic Ecology. - : Springer. - 1386-2588 .- 1573-5125. ; 55:4, s. 1157-1169
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Tidskriftsartikel (refereegranskat)abstract
- Diel vertical migration (DVM) is the most common behavioral phenomenon in zooplankton, and numerous studies have evaluated DVM under strong seasonality at higher latitudes. Yet, our understanding of the environmental drivers of DVM at low latitudes, where seasonal variation is less pronounced, remains limited. Therefore, we here examined patterns of vertical distribution in copepods in six subtropical Bahamian blue holes with different food web structure and tested the role of several key environmental variables potentially affecting this behavior. Day and night samplings showed that copepods generally performed DVM, characterized by downward migration to deeper depths during the day and upward migration to surface waters at night. Across all blue holes, the daytime vertical depth distribution of calanoid copepods correlated positively with both predation risk and depth of food resources (Chlorophyll a), but was less affected by ultraviolet radiation (UVR). A potential explanation is that since UVR is a continuous threat across seasons, zooplankton have established photoprotective pigmentation making them less vulnerable to this threat. The copepods also showed a size-structured depth segregation, where larger individuals were found at deeper depths during the day, which further strengthens the suggestion that predation is a major driver of DVM in these systems. Hence, in contrast to studies performed at higher latitudes, we show that despite the constant exposure to UVR, predator avoidance and food availability are the most pronounced drivers of copepod DVM at those low latitudes, suggesting that the main driver of DVM may vary among systems, but also systematically by latitude.
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| 19. |
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| 20. |
- Sulheim, Einar, et al.
(författare)
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Contrast Enhanced Magnetic Resonance Imaging of Amyloid-beta Plaques in a Murine Alzheimers Disease Model
- 2023
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Ingår i: Journal of Alzheimer's Disease. - : IOS PRESS. - 1387-2877 .- 1875-8908. ; 93:2, s. 411-419
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Tidskriftsartikel (refereegranskat)abstract
- Background: Early detection of amyloid-beta(A beta) aggregates is a critical step to improve the treatment of Alzheimers disease (AD) because neuronal damage by the A beta aggregates occurs before clinical symptoms are apparent. We have previously shown that luminescent conjugated oligothiophenes (LCOs), which are highly specific towards protein aggregates of A beta, can be used to fluorescently label amyloid plaque in living rodents. Objective: We hypothesize that the LCO can be used to target gadolinium to the amyloid plaque and hence make the plaque detectable by T-1-weighted magnetic resonance imaging (MRI). Methods: A novel LCO-gadolinium construct was synthesized to selectively bind to A beta plaques and give contrast in conventional T-1-weighted MR images after intravenous injection in Tg-APPSwe mice. Results: We found that mice with high plaque-burden could be identified using the LCO-Gd constructs by conventional MRI. Conclusion: Our study shows that MR imaging of amyloid plaques is challenging but feasible, and hence contrast-mediated MR imaging could be a valuable tool for early AD detection.
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| 21. |
- Svahn, Sara L, et al.
(författare)
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Dietary Omega-3 Fatty Acids Increase Survival and Decrease Bacterial Load in Mice Subjected to Staphylococcus aureus-Induced Sepsis
- 2016
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Ingår i: Infection and Immunity. - : American Society for Microbiology. - 0019-9567 .- 1098-5522. ; 84:4, s. 1205-1213
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Tidskriftsartikel (refereegranskat)abstract
- Sepsis caused by Staphylococcus aureus is increasing in incidence. With the alarming use of antibiotics, S. aureus is prone to become methicillin resistant. Antibiotics are the only widely used pharmacological treatment for sepsis. Interestingly, mice fed high-fat diet (HFD) rich in polyunsaturated fatty acids have better survival of S. aureus-induced sepsis than mice fed HFD rich in saturated fatty acids (HFD-S). To investigate what component of polyunsaturated fatty acids, i.e., omega-3 or omega-6 fatty acids, exerts beneficial effects on the survival of S. aureus-induced sepsis, mice were fed HFD rich in omega-3 or omega-6 fatty acids for 8 weeks prior to inoculation with S. aureus. Further, mice fed HFD-S were treated with omega-3 fatty acid metabolites known as resolvins. Mice fed HFD rich in omega-3 fatty acids had increased survival and decreased bacterial loads compared to those for mice fed HFD-S after S. aureus-induced sepsis. Furthermore, the bacterial load was decreased in resolvin-treated mice fed HFD-S after S. aureus-induced sepsis compared with that in mice treated with vehicle. Dietary omega-3 fatty acids increase the survival of S. aureus-induced sepsis by reversing the deleterious effect of HFD-S on mouse survival.
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| 22. |
- Tjernberg, Anna Rockert, et al.
(författare)
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Celiac disease and complement activation in response to Streptococcus pneumoniae
- 2020
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Ingår i: European Journal of Pediatrics. - : Springer. - 0340-6199 .- 1432-1076. ; 179:1, s. 133-140
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Tidskriftsartikel (refereegranskat)abstract
- Individuals with celiac disease (CD) are at increased risk of invasive pneumococcal disease (IPD). The aim of this study was to explore whether the complement response to Streptococcus pneumoniae differed according to CD status, and could serve as an explanation for the excess risk of IPD in CD. Twenty-two children with CD and 18 controls, born 1999-2008, were included at Kalmar County Hospital, Sweden. The degree of complement activation was evaluated by comparing levels of activation products C3a and sC5b-9 in plasma incubated for 30 min with Streptococcus pneumoniae and in non-incubated plasma. Complement analyses were performed with enzyme-linked immunosorbent assay (ELISA). Pneumococcal stimulation caused a statistically significant increase in C3a as well as sC5b-9 in both children with CD and controls but there was no difference in response between the groups. After incubation, C3a increased on average 4.6 times and sC5b-9 22 times in both the CD and the control group (p = 0.497 and p = 0.724 respectively). Conclusion: Complement response to Streptococcus pneumoniae seems to be similar in children with and without CD and is thus unlikely to contribute to the increased susceptibility to invasive pneumococcal disease in CD.
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| 23. |
- Uhlén, Mathias, et al.
(författare)
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A human protein atlas for normal and cancer tissues based on antibody proteomics
- 2005
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 4:12, s. 1920-1932
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Tidskriftsartikel (refereegranskat)abstract
- Antibody-based proteomics provides a powerful approach for the functional study of the human proteome involving the systematic generation of protein-specific affinity reagents. We used this strategy to construct a comprehensive, antibody-based protein atlas for expression and localization profiles in 48 normal human tissues and 20 different cancers. Here we report a new publicly available database containing, in the first version, similar to 400,000 high resolution images corresponding to more than 700 antibodies toward human proteins. Each image has been annotated by a certified pathologist to provide a knowledge base for functional studies and to allow queries about protein profiles in normal and disease tissues. Our results suggest it should be possible to extend this analysis to the majority of all human proteins thus providing a valuable tool for medical and biological research.
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| 24. |
- Wikberg-Nilsson, Åsa, et al.
(författare)
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Tillgänglighetsdesign för stadens utveckling
- 2018
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Rapport (populärvet., debatt m.m.)abstract
- Det offentliga rummet: stadens gator, parker, byggnader och torg likväl som den kultur och sociala kontext som en viss stad har, skulle kunna utformas för att vara tillgängligt, användbart, inkluderande, attraktivt och välgörande för människan i betydligt större utsträckning än vad som görs idag. Troligtvis är det inte medveten diskriminering som ligger bakom mindre god design av det offentliga rummet, utan snarare okunskap om vad som kan och behöver göras. Fram tills dess människor befinner sig i en situation där de på något sätt själva är hindrade från att delta på lika villkor är det svårt att inse hur mycket det offentliga rummet påverkar oss. Det kan vara mindre hinder i form av ojämnt underlag som gör det svårt att ta sig fram för vissa, medan det omöjliggör framfart för andra. Det kan vara miljöer som vissa upplever som “vanliga” medan andra upplever sig djupt otrygga eller utestängda från desamma. Med andra ord är det offentliga rummets utrymmen där vi lever, jobbar och leker knutna till vart vi går och vad vi gör eller vart vi inte går eller gör. Av den anledningen anser vi att det finns behov av att utveckla konkreta metoder och handgripliga råd för att arbeta med mer medveten utformning av fysisk miljö: tillgänglighetsdesign. Tillgänglighetsdesign används här genomgående som ett brett begrepp för design av lösningar som upplevs trygga, användbara, inkluderande, attraktiva och välgörande. Vi utgår från en designpraktik som stödjer tanken att miljön måste vara tillgänglig för alla grupper i samhället. I det förstudieprojekt som beskrivs i kommande kapitel har av den anledningen en kartläggning skett med utgångspunkt i ett helhetsgrepp på tillgänglighetsdesign, det vill säga att motverka diskriminering och främja lika rättighter och möjligheter oavsett kön, könsöverskridande identitet eller uttryck, etnisk tillhörighet, religion eller annan trosuppfattning, funktionsnedsättning, sexuell läggning eller ålder. Förstudien har omfattat kartläggning av normkritiska perspektiv, lagar och riktlinjer kring fysisk tillgänglighet, social hållbarhet och tillgänglighet, universell och inkluderande design, samt inhämtning av inspiration från arkitektur, form och designområdet. Det har även omfattat identifiering av goda exempel från runt om i landet på vad tillgänglighetsdesign i bred bemärkelse kan omfatta och intervjuer med personer som arbetat med detta. Vi vill rikta ett stort tack till er som bidragit till arbetet. Vår avsikt är att de principer som utformats i förstudien för tillgänglighetsdesign ska diskuteras, användas och uppdateras vid all stadsutveckling. På så sätt kan vi åstadkomma ett helhetsgrepp på tillgänglighetsdesign och åstadkomma socialt hållbara, attraktiva och tillgängliga platser och miljöer runt om i landet.
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| 25. |
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| 26. |
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| 27. |
- Abdulla, Parosh Aziz, et al.
(författare)
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Algorithmic Improvements in Regular Model Checking
- 2003
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Regular model checking is a form of symbolic model checking for parameterized and infinite-state systems, whose states can be represented as finite strings of arbitrary length over a finite alphabet, in which regular sets of words are used to represent sets of states. In earlier papers, we have developed methods for computing the transitive closure (or the set of reachable states) of the transition relation, represented by a regular length-preserving transducer. In this paper, we present several improvements of these techniques, which reduce the size of intermediate approximations of the transitive closure: One improvement is to pre-process the transducer by \em bi-determinization, another is to use a more powerful equivalence relation for identifying histories (columns) of states in the transitive closure. We also present a simplified theoretical framework for showing soundness of the optimization, which is based on commuting simulations. The techniques have been implemented, and we report the speedups obtained from the respective optimizations.
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| 28. |
- Abdulla, Parosh Aziz, et al.
(författare)
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Handling Global Conditions in Parameterized System Verification
- 1999
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Ingår i: Proc. 11th Int. Conf. on Computer Aided Verification. - Berlin : Springer Verlag. - 3540662022 ; , s. 134-145
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Konferensbidrag (refereegranskat)abstract
- We consider symbolic verification for a class of parameterized systems, where a system consists of a linear array of processes, and where an action of a process may in general be guarded by both local conditions restricting the state of the process about to perform the action, and global conditions defining the context in which the action is enabled. Such actions are present, e.g., in idealized versions of mutual exclusion protocols, such as the bakery and ticket algorithms by Lamport, Burn’s protocol, Dijkstra’s algorithm, and Szymanski’s algorithm. The presence of both local and global conditions makes the parameterized versions of these protocols infeasible to analyze fully automatically, using existing model checking methods for parameterized systems. In all these methods the actions are guarded only by local conditions involving the states of a finite set of processes. We perform verification using a standard symbolic reachability algorithm enhanced by an operation to accelerate the search of the state space. The acceleration operation computes the effect of an arbitrary number of applications of an action, rather than a single application. This is crucial for convergence of the analysis e.g. when applying the algorithm to the above protocols. We illustrate the use of our method through an application to Szymanski’s algorithm.
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| 29. |
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| 30. |
- Abdulla, Parosh Aziz, et al.
(författare)
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Regular Model Checking for LTL(MSO)
- 2004
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Ingår i: Proc. 16th Int. Conf. on Computer Aided Verification, LNCS.
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Tidskriftsartikel (refereegranskat)
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| 31. |
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| 32. |
- Abdulla, Parosh, et al.
(författare)
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A Survey of Regular Model Checking.
- 2004
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Ingår i: CONCUR 2004 - Concurrency Theory. - 354022940X ; , s. 35-48
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Konferensbidrag (refereegranskat)abstract
- Regular model checking is being developed for algorithmic verification of several classes of infinite-state systems whose configurations can be modeled as words over a finite alphabet. Examples include parameterized systems consisting of an arbitrary number of homogeneous finite-state processes connected in a linear or ring-formed topology, and systems that operate on queues, stacks, integers, and other linear data structures. The main idea is to use regular languages as the representation of sets of configurations, and finite-state transducers to describe transition relations. In general, the verification problems considered are all undecidable, so the work has consisted in developing semi-algorithms, and decidability results for restricted cases. This paper provides a survey of the work that has been performed so far, and some of its applications.
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| 33. |
- Abdulla, Parosh, et al.
(författare)
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Regular Model Checking for LTL(MSO)
- 2004
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Ingår i: Computer Aided Verification. - 3540223428 ; , s. 348-360
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Konferensbidrag (refereegranskat)abstract
- Regular model checking is a form of symbolic model checking for parameterized and infinite-state systems whose states can be represented as words of arbitrary length over a finite alphabet, in which regular sets of words are used to represent sets of states. We present $\logic$, a combination of the logics MSO and LTL as a natural logic for expressing temporal properties to be verified in regular model checking. $\logic$ is a two-dimensional modal logic, where MSO is used for specifying properties of system states and transitions, and LTL is used for specifying temporal properties. In addition, the first-order quantification in MSO can be used to express properties parameterized on a position or process.We give a technique for model checking $\logic$, which is adapted from the automata-theoretic approach: a formula is translated to a (\buchi) transducer with a regular set of accepting states, and regular model checking techniques are used to search for models. We have implemented the technique and show its application to a number of parameterized algorithms from the literature.
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| 34. |
- Abdulla, Parosh, et al.
(författare)
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Regular model checking for LTL(MSO)
- 2012
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Ingår i: International Journal on Software Tools for Technology Transfer. - Springer : Springer Science and Business Media LLC. - 1433-2779 .- 1433-2787. ; 14:2, s. 223-241
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Tidskriftsartikel (refereegranskat)abstract
- Regular model checking is a form of symbolic model checking for parameterized and infinite-state systems whose states can be represented as words of arbitrary length over a finite alphabet, in which regular sets of words are used to represent sets of states. We present LTL(MSO), a combination of the logics MSO and LTL as a natural logic for expressing temporal properties to be verified in regular model checking. In other words, LTL(MSO) is a natural specification language for both the system and the property under consideration. LTL(MSO) is a two-dimensional modal logic, where MSO is used for specifying properties of system states and transitions, and LTL is used for specifying temporal properties. In addition, the first-order quantification in MSO can be used to express properties parameterized on a position or process. We give a technique for model checking LTL(MSO), which is adapted from the automata-theoretic approach: a formula is translated to a Buechi regular transition system with a regular set of accepting states, and regular model checking techniques are used to search for models. We have implemented the technique, and show its application to a number of parameterized algorithms from the literature.
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| 35. |
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| 36. |
- Adman, Per, et al.
(författare)
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171 forskare: ”Vi vuxna bör också klimatprotestera”
- 2019
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Ingår i: Dagens nyheter (DN debatt). - Stockholm. - 1101-2447.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- DN DEBATT 26/9. Vuxna bör följa uppmaningen från ungdomarna i Fridays for future-rörelsen och protestera eftersom det politiska ledarskapet är otillräckligt. Omfattande och långvariga påtryckningar från hela samhället behövs för att få de politiskt ansvariga att utöva det ledarskap som klimatkrisen kräver, skriver 171 forskare i samhällsvetenskap och humaniora.
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| 37. |
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| 38. |
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| 39. |
- Albertsson-Wikland, Kerstin, 1947, et al.
(författare)
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Dose-dependent effect of growth hormone on final height in children with short stature without growth hormone deficiency
- 2008
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 93:11, s. 4342-4350
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: The effect of GH therapy in short non-GH-deficient children, especially those with idiopathic short stature (ISS), has not been clearly established owing to the lack of controlled trials continuing until final height (FH).OBJECTIVE: The aim of the study was to investigate the effect on growth to FH of two GH doses given to short children, mainly with ISS, compared with untreated controls.DESIGN AND SETTING: A randomized, controlled, long-term multicenter trial was conducted in Sweden.INTERVENTION: Two doses of GH (Genotropin) were administered, 33 or 67 microg/kg.d; control subjects were untreated.SUBJECTS: A total of 177 subjects with short stature were enrolled. Of these, 151 were included in the intent to treat (AllITT) population, and 108 in the per protocol (AllPP) population. Analysis of ISS subjects included 126 children in the ITT (ISSITT) population and 68 subjects in the PP (ISSPP) population.MAIN OUTCOME MEASURES: We measured FH sd score (SDS), difference in SDS to midparenteral height (diff MPHSDS), and gain in heightSDS.RESULTS: After 5.9+/-1.1 yr on GH therapy, the FHSDS in the AllPP population treated with GH vs. controls was -1.5+/-0.81 (33 microg/kg.d, -1.7+/-0.70; and 67 microg/kg.d, -1.4+/-0.86; P<0.032), vs. -2.4+/-0.85 (P<0.001); the diff MPHSDS was -0.2+/-1.0 vs. -1.0+/-0.74 (P<0.001); and the gain in heightSDS was 1.3+/-0.78 vs. 0.2+/-0.69 (P<0.001). GH therapy was safe and had no impact on time to onset of puberty. A dose-response relationship identified after 1 yr remained to FH for all growth outcome variables in all four populations.CONCLUSION: GH treatment significantly increased FH in ISS children in a dose-dependent manner, with a mean gain of 1.3 SDS (8 cm) and a broad range of response from no gain to 3 SDS compared to a mean gain of 0.2 SDS in the untreated controls.
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| 40. |
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| 41. |
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| 42. |
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| 43. |
- Almqvist, Monica, et al.
(författare)
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Characterization of micromachined ultrasonic transducers using light diffraction tomography
- 2005
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Ingår i: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. - 0885-3010. ; 52:12, s. 2298-2302
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Tidskriftsartikel (refereegranskat)abstract
- This paper demonstrates that light diffraction tomography can be used to measure the acoustic field of micromachined ultrasonic transducers (MUT) in cases in which standard methods like hydrophone and microphone measurements fail. Two types of MUTs have been characterized with the method, one air-coupled capacitive MUT (cMUT) and one waterloaded continuous wave (CW) miniature multilayer lead zirconate titanate (PZT) transducer. Light diffraction tomography is an ultrasound measurement method with some special characteristics. Based on the interaction of light and ultrasound, it combines light intensity measurements with tomography algorithms to produce a measurement system. The method offers nonperturbing pressure measurements with high spatial resolution. It has been shown that, under certain circumstances, light diffraction tomography can be used as an absolute pressure measurement method with accuracy in the order of 10% in water and 13% in air. The results show that air-coupled cMUTs in the frequency range of about 1 MHz as well as the extreme near field of a miniaturized CW 10 MHz waterloaded transducer were successfully characterized with light diffraction tomography.
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| 44. |
- Alves, Mariana, et al.
(författare)
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NOVA : Verktyg och metoder för normkreativ innovation
- 2016
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Rapport (populärvet., debatt m.m.)abstract
- Alla är sig själv närmast. Och vi gör oftast som vi är vana att göra. Vi styrs av de normer och värderingar som har format oss - även om vi tror att vi är innovativa. Resultatet riskerar att bli lösningar som diskriminerar och begränsar. En stor utmaning är att förstå andra människors behov. Om vi kan använda ett normkritiskt perspektiv och se bortom våra egna ramar kan vi nå en större potential inom innovation. Men att förverkliga den potentialen är lättare sagt än gjort. Det krävs vad vi kallar normkreativitet. Normkreativitet bygger på en medvetenhet om att normer och värderingar kan begränsa och diskriminera. Men den kräver också ett analytiskt arbete att undersöka människors verkliga situation och djupliggande behov - och samtidigt ett kreativt arbete att omsätta kritik och kunskap i nya lösningar. NOVA innehåller konkreta verktyg och handfasta metoder för alla som vill skapa sådana normkreativa lösningar. Materialet är baserat på praktiskt erfarenhet och forskning från en mängd olika projekt och studier. Formatet är valt för att gynna kreativitet och samverkan. Fokus är på normer som diskriminerar, men egentligen är innehållet användbart i alla innovationssammanhang. All innovation handlar ju om att utmana normer.
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| 45. |
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| 46. |
- Andersson, Erik, 1979-, et al.
(författare)
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Kollegialt Lärande i Örebros Skolor – KLÖS-projektet : Hur kan lärares kollegiala lärprocesser stödjas i syfte att skapa hållbara strukturer för utvecklingsarbete?
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Projektet KLÖS har undersökt hur lärares kollegiala lärprocesser kan stödjas i syfte att skapa hållbara strukturer för utvecklingsarbete. Målet var att skapa en Örebromodell för kollegialt lärande. En avslutande reflektion kring resultatet är att etableringen av denna modell kräver ett omfattande engagemang och tar tid att få på plats. Det är vår uppfattning att ett flertal aspekter återstår att undersöka. Bland annat är det intressant att undersöka hur arbetet med det kollegiala lärandet fortskrider på pilotskolan. Frågor som är intressanta är: Vilka faktorer har betydelse för att arbetet med kollegialt lärande ska bli permanent och fungera som ett naturligt sätt att arbeta med utveckling av praktiken? Vad blir resultatet av de utvecklingsomgångar som genomförts? Hur följs detta resultat upp och leder det till bestående gynnsamma förändringar? Frågorna handlar om hållbarhet och därmed om hur projektet går från att vara ett projekt som avslutas och glöms bort till att bli ett levande verktyg för utvecklingsarbete som kan göra en verklig skillnad i och för praktiken över tid. Eftersom mycket tid och resurser används till utvecklingsarbete i skolan är det viktigt att det arbete som görs verkligen leder till en konkret och för verksamheten gynnsam förändring. Det innebär att frågan om utvecklings- arbetets hållbarhet är en av de viktigaste frågorna. Det verktyg som utvecklats i projektet och som kommit att symbolisera det kollegiala arbetet på pilotskolan är KLÖS-hjulet. Frågan om hur KLÖS-hjulet 2.0 kan utvecklas och anpassas så att det verkligen blir ett flexibelt och användbart verktyg för att stötta det kollegiala lärandet är kanske den alla viktigaste konkreta frågan. Frågor som är besläktade med frågan om hållbarhet är de som syftar till att undersöka hur det kollegiala lärandet kan bli mer robust. Till dessa hör frågor om hur lärledarens roll kan förstärkas, hur verktyg som stöttar lärares observation och analys av den egna verksamheten kan designas, hur ansvar och engagemang på alla nivåer kan förstärkas och bli synligt samt hur arbetet med kollegialt lärande kan utvärderas. Vi har under projektets gång sett hur lärare behöver stöd i arbetet med att systematiskt identifiera behov i verksamheten för att sedan utforska möjligheter att utveckla och förändra praktiken. Medverkan från forskare som ställt frågor, problematiserat och belyst olika perspektiv har i flera fall varit avgörande för hur ett utvecklingsbehov har identifierats, avgränsats och formulerats som en undersökningsbar fråga. Det är av avgörande betydelse att utvecklingsarbetet inte står och faller med denna medverkan. Verksamheten måste själv ta fram strukturer för hur lärare och lärledare får ett tillfredsställande stöd i sitt utvecklingsarbete så att de har möjlighet att göra kollegialt lärande till en naturlig del av sitt arbete där de känner sig så bekanta med KLÖS-hjulet att de själva kan ställa de frågor som krävs. Således behöver många funktioner, både centralt och lokalt samverka för att vidareutveckla och stötta kollegialt lärande för att utveckla undervisningen i Örebro skolor.
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| 47. |
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| 48. |
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| 49. |
- Andersson, Marcus, 1975, et al.
(författare)
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Quartz crystal microbalance-with dissipation monitoring (QCM-D) for real time measurements of blood coagulation density and immune complement activation on artificial surfaces
- 2005
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Ingår i: Biosensors & Bioelectronics. - : Elsevier BV. - 0956-5663. ; 21:1, s. 79-86
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Tidskriftsartikel (refereegranskat)abstract
- A recently developed variant of quartz crystal microbalance (QCM) called QCM-with dissipation monitoring (QCM-D) allows simultaneous and simple measurements of changes in adsorbed mass as well as the viscoelastic property (D-factor) of deposited protein layers on the sensor surface. We have taken the QCM-D technology a step further and demonstrated its advantages in the study of protein assembly as a consequence of surface induced immune complement activation, or contact activated blood coagulation. In the present study we have continued our QCM-D investigations of surface assembly of fibrin clot formation and complement activation and incubated differently modified quartz sensor surfaces in blood plasma and sera. Polymer surfaces used were spin-coated polyethylene, poly(ethylene terephtalate), poly(methylmetacrylate) and poly(dimethylsiloxane). Also used were sputtered titanium and heparin grafted surfaces. In this investigation we found that we could describe the surface induced coagulation with four independent parameters: (1) Time of onset of coagulation, (2) fibrin deposition rate, (3) total frequency shift at stable plateau, and (4) fibrin clot density. The most important finding was that the blood plasma clot density can be assessed with the use of D determinations and that the clot density varied significantly with the chemical composition of the surface. However, the D-factor did not give any new analytical information about the possible complement activation mechanisms. Nevertheless, the QCM-D was found to be a reliable tool for the analysis of surface induced complement activation. We also compared the QCM-D technique with traditional enzyme immuno assay (EIA) measurements of soluble products from the surface activation of the complement and coagulation systems. We found that the results from EIA and QCM-D measurements corresponded well for the complement activation but not for the coagulation, probably due to the biological complexity of the coagulation system.
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| 50. |
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