| 1. |
- Ambjørn, J., et al.
(författare)
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Langevin simulations of configurations with static charges
- 1985
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Ingår i: Physics Letters B. - 0370-2693. ; 159:4-6, s. 335-340
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Tidskriftsartikel (refereegranskat)abstract
- By using the Langevin equation with complex action it is possible to generate (complex) configurations in the charged sector of gauge theories. We test the algorithm in the case of two-dimensional U(1) gauge theory and are able to measure the string tension with great precision and modest use of computer time for a separation of the charged particles where a conventional Wilson loop would have a value ≈ 10-10.
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| 2. |
- Ambjørn, J., et al.
(författare)
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The complex langevin equation and Monte Carlo simulations of actions with static charges
- 1986
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Ingår i: Nuclear Physics, Section B. - 0550-3213. ; 275:3, s. 375-397
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Tidskriftsartikel (refereegranskat)abstract
- We explore the possibilities of using the complex Langevin equation to Monte Carlo generate configurations of gauge theories with static charges present in the action. Successful results are obtained for systems that possess nontrivial saddle-point (classical) solutions. For that reason the algorithm works impressively for two-dimensional U(1) in the entire β-range whereas for three- and four-dimensional U(1) the applicability is limited to the weak coupling regime (large β). The method fails completely for SU(2) and SU(3).
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| 3. |
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| 4. |
- Feldman, Adina L., et al.
(författare)
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Accuracy and Sensitivity of Parkinsonian Disorder Diagnoses in Two Swedish National Health Registers
- 2012
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Ingår i: Neuroepidemiology. - : S. Karger AG. - 1423-0208 .- 0251-5350. ; 38:3, s. 186-193
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Tidskriftsartikel (refereegranskat)abstract
- Background: Swedish population-based national health registers are widely used data sources in epidemiological research. Register-based diagnoses of Parkinson's disease have not been validated against clinical information. Methods: Parkinson's disease (PD) and other parkinsonian disorder diagnoses were ascertained in two registers, i.e. the National Patient Register (NPR) and the Cause of Death Register (CDR). Diagnoses were validated in terms of accuracy (positive predictive value) and sensitivity against data from a population-based study of PD in 1998-2004 that screened more than 35,000 persons and identified 194 cases of parkinsonian disorders including 132 PD cases (the gold standard for the purposes of this study). Results: Accuracy for any parkinsonian disorder diagnoses was 88.0% in the NPR and 94.4% in the CDR. Accuracy of PD diagnoses was 70.8% in the NPR and 66.7% in the CDR. Misclassification between differential parkinsonian diagnoses was common. The accuracy of PD diagnoses in the NPR improved to 83.0% by restricting the definition to primary diagnoses only. The sensitivity of PD diagnoses in the NPR and CDR combined was 83.1%, with a mean time to detection of 6.9 years. Conclusions: Population-based national health registers are valid data sources in epidemiological studies of PD or parkinsonian disorder etiology but are less suitable in studies of incidence or prevalence. Copyright (C) 2012 S. Karger AG, Basel
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| 5. |
- Flensburg, M., et al.
(författare)
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Applications of an improved bag model
- 1984
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Ingår i: Zeitschrift für Physik C Particles and Fields. - 0170-9739. ; 22:3, s. 293-300
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Tidskriftsartikel (refereegranskat)abstract
- Phenomenological consequences of a recently improved and unified study of the lowestlying hadrons in the MIT Bag model are explored. In contrast to earlier fits we find the new values for the Bag constant B1/4(200-230 MeV) and the hadronic radii R0(≈3.2 GeV-1) to be consistent with present estimates of the gluon condensate {Mathematical expression}, the Hagedorn temperature TH and experimental hyperon decay rates. We also calculate the {Mathematical expression} spectrum within the same MIT Bag model framework and find for the exotic state m1-+≃1400 MeV. This result roughly agrees with earlier estimates using different methods and parameters.
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| 6. |
- Flensburg, M., et al.
(författare)
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Measurement of Tc in the scaling region of (2+1)-dimensional SU(2) lattice gauge theory
- 1986
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 175:2, s. 187-191
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Tidskriftsartikel (refereegranskat)abstract
- The deconfinement temperature Tc of (2+1)-dimensional SU(2) gauge theory is measured on lattice sizes varying from 2 × 202 to 6 × 602 and with β in the rate 3-9. Approximative scaling is found for β > 6.5 and Tc/√σ = 0.94 ± 0.03 is obtained. This value is in excellent agreement with (3/π) 1 2, as predicted from the breakdown of SU(2) confinement in terms of an effective scalar string theory.
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| 7. |
- Flensburg, M., et al.
(författare)
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String model potentials and lattice gauge theories
- 1987
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Ingår i: Nuclear Physics, Section B. - : Elsevier BV. - 0550-3213. ; 283, s. 141-164
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Tidskriftsartikel (refereegranskat)abstract
- The static potentials from bosonic string models are examined to the two-loop level. Available MC data for 4-dimensional SU(3) are in approximate agreement with the universal leading order predictions but fail to reproduce the Nambu string when the two-loop terms are included in the analysis. We also confront Nambu string model predictions for Tc σ with SU(2), SU(3) and SU(N → ∞) MC data. In the SU(2) case, impressive agreement is found both in 3 and 4 dimensions. In contrast, the data for SU(3) and SU(N → ∞) differ from the string model prediction. These theories have identical values for Tc σ, indicating that N → ∞ is a good approximation to N = 3.
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| 8. |
- Flensburg, M., et al.
(författare)
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Strings and SU(3) lattice gauge theory
- 1985
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 153:6, s. 412-416
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Tidskriftsartikel (refereegranskat)abstract
- Recent SU(3) lattice Monte Carlo data (244 and 164) are analyzed in terms of a simple string model. Good agreement is found. Observed similarities between SU(3) and three-dimensional SU(2) indicate that the string theory is indeed an effective one.
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| 9. |
- Flensburg, M., et al.
(författare)
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The effective string and SU(2) lattice MC data
- 1987
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Ingår i: Zeitschrift für Physik C Particles and Fields. - 0170-9739. ; 36:4, s. 629-637
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Tidskriftsartikel (refereegranskat)abstract
- We present high statistics MC calculations of the static potential in three-dimensional SU(2) for a wide range of β values on a 243 lattice. The deviations from area law are unambiguously demonstrated by use of 2nd lattice R derivative. After a clear crossover at β=4.5 the data show signs of an effective string roughening up to β=6.5, while scaling is not strictly obeyed in this interval. Pure fermionic strings do not provide better fits. The effect of regularization prescription on the effective string model up to two-loop correction is discussed and is found to be small. We also make a comparative study of existing data on Z(2) and SU(3) together with new data on fourdimensional SU(2) presented here. It is pointed out that standard variance reduction methods as applied especially to Wilson lines are plagued by severe long range auto-correlations, whereas larger Wilson loops are less affected.
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| 10. |
- Wirdefeldt, Karin, et al.
(författare)
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Complete ascertainment of Parkinson disease in the Swedish Twin Registry
- 2008
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 1558-1497 .- 0197-4580. ; 29:12, s. 1765-1773
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Tidskriftsartikel (refereegranskat)abstract
- This report describes the ascertainment of Parkinson disease (PD) in all individuals aged 50 years or older (49,814 individuals) from the Swedish Twin Registry. In phase one of the study, all twins were screened for PD using telephone interviews, with a response rate of 72.7%. In phase two, twins with suspected PD were re-contacted to exclude anyone from follow-up who reported parkinsonian symptoms due to diseases other than PD. In the third phase, in-person clinical evaluations were completed for twins who were still considered PD suspects after phase two and for a sample of co-twins. During the clinical evaluations, we also collected blood samples and information about a variety of environmental exposures. Overall prevalence rate for PD was 496 per 100,000 individuals. Among the 132 PD cases identified, there were only three concordant twin pairs. In total 7.2% of PD cases reported a first degree relative with PD.
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