2,659 research outputs found
Three-dimensional U(1) gauge+Higgs theory as an effective theory for finite temperature phase transitions
We study the three-dimensional U(1)+Higgs theory (Ginzburg-Landau model) as
an effective theory for finite temperature phase transitions from the 1 K scale
of superconductivity to the relativistic scales of scalar electrodynamics. The
relations between the parameters of the physical theory and the parameters of
the 3d effective theory are given. The 3d theory as such is studied with
lattice Monte Carlo techniques. The phase diagram, the characteristics of the
transition in the first order regime, and scalar and vector correlation lengths
are determined. We find that even rather deep in the first order regime, the
transition is weaker than indicated by 2-loop perturbation theory. Topological
effects caused by the compact formulation are studied, and it is demonstrated
that they vanish in the continuum limit. In particular, the photon mass
(inverse correlation length) is observed to be zero within statistical errors
in the symmetric phase, thus constituting an effective order parameter.Comment: 42 pages, 14 figure
Vortices in equilibrium scalar electrodynamics
Scalar electrodynamics can be used to investigate the formation of cosmic
strings in the early universe. We present the results of lattice Monte Carlo
simulations of an effective three-dimensional U(1)+Higgs theory that describes
the equilibrium properties of finite-temperature scalar electrodynamics near
the transition. A gauge-invariant criterion for the existence of a vortex is
used in measuring the properties of the vortex network in the equilibrium state
both in the Coulomb and in the Higgs phase of the system. The naive definition
of the vortex density becomes meaningless in the continuum limit and special
care is needed in extracting physical quantities. Numerical evidence for a
physical discontinuity in the vortex density is given.Comment: 4 pages. Talk given by A. Rajantie at PASCOS-98, March 199
The GROUSE project III: Ks-band observations of the thermal emission from WASP-33b
In recent years, day-side emission from about a dozen hot Jupiters has been
detected through ground-based secondary eclipse observations in the
near-infrared. These near-infrared observations are vital for determining the
energy budgets of hot Jupiters, since they probe the planet's spectral energy
distribution near its peak. The aim of this work is to measure the Ks-band
secondary eclipse depth of WASP-33b, the first planet discovered to transit an
A-type star. This planet receives the highest level of irradiation of all
transiting planets discovered to date. Furthermore, its host-star shows
pulsations and is classified as a low-amplitude delta-Scuti. As part of our
GROUnd-based Secondary Eclipse (GROUSE) project we have obtained observations
of two separate secondary eclipses of WASP-33b in the Ks-band using the LIRIS
instrument on the William Herschel Telescope (WHT). The telescope was
significantly defocused to avoid saturation of the detector for this bright
star (K~7.5). To increase the stability and the cadence of the observations,
they were performed in staring mode. We collected a total of 5100 and 6900
frames for the first and the second night respectively, both with an average
cadence of 3.3 seconds. On the second night the eclipse is detected at the
12-sigma level, with a measured eclipse depth of 0.244+0.027-0.020 %. This
eclipse depth corresponds to a brightness temperature of 3270+115-160 K. The
measured brightness temperature on the second night is consistent with the
expected equilibrium temperature for a planet with a very low albedo and a
rapid re-radiation of the absorbed stellar light. For the other night the short
out-of-eclipse baseline prevents good corrections for the stellar pulsations
and systematic effects, which makes this dataset unreliable for eclipse depth
measurements. This demonstrates the need of getting a sufficient out-of-eclipse
baseline.Comment: 12 pages, 10 figures. Accepted for publication in Astronomy and
Astrophysic
Mendelian randomization highlights insomnia as a risk factor for pain diagnoses
Study Objective: Insomnia has been linked to acute and chronic pain conditions; however, it is unclear whether such relationships are causal. Recently, a large number of genetic variants have been discovered for both insomnia and pain through genome-wide association studies (GWASs) providing a unique opportunity to examine the evidence for causal relationships through the use of the Mendelian randomization paradigm. Methods: To elucidate the causality between insomnia and pain, we performed bidirectional Mendelian randomization analysis in FinnGen, where clinically diagnosed ICD-10 categories of pain had been evaluated. In addition, we used measures of self-reported insomnia symptoms. We used endpoints for pain in the FinnGen Release 5 (R5) (N = 218,379), and a non-overlapping sample for insomnia (UK Biobank (UKBB) and 23andMe, N = 1,331,010 or UKBB alone N = 453,379). We assessed the robustness of results through conventional Mendelian randomization sensitivity analyses. Results: Genetic liability to insomnia symptoms increased the odds of reporting pain (odds ratio (OR) [95% confidence interval (CI)] = 1.47 [1.38-1.58], p = 4.12 x 10(-28)). Manifested pain had a small effect on increased risk for insomnia (OR [95% CI] = 1.04 [1.01-1.07], p < 0.05). Results were consistent in sensitivity analyses. Conclusions: Our findings support a bidirectional causal relationship between insomnia and pain. These data support a further clinical investigation into the utility of insomnia treatment as a strategy for pain management and vice versa.Peer reviewe
The order of the phase transition in 3d U(1)+Higgs theory
We study the order of the phase transition in the 3d U(1)+Higgs theory, which
is the Ginzburg-Landau theory of superconductivity. We confirm that for small
scalar self-coupling the transition is of first order. For large scalar
self-coupling the transition ceases to be of first order, and a non-vanishing
scalar mass suggests that the transition may even be of higher than second
order.Comment: Poster at LATTICE96(electroweak). 4 pages, 5 figure
Seamless nowcasting system development at the Finnish Meteorological Institute
Presentación realizada en la 3rd European Nowcasting Conference, celebrada en la sede central de AEMET en Madrid del 24 al 26 de abril de 2019
Frequent pain in older people with and without diabetes - Finnish community based study
Background: The association between pain and diabetes in older people has been largely unexplored. The aim of this survey was to analyze the prevalence and characteristics of pain among Finnish men and women 65 or older with and without diabetes in primary care. Methods: All home-dwelling persons 65 years or older with diabetes (N = 527) and age and gender matched controls (N = 890) were identified from electronic patient records. Frequent pain was regarded as any pain experienced more often than once a week, and it was divided into pain experienced several times a week but not daily and pain experienced daily or continuously. The Numeric Rating Scale (0-10) (NRS) was used to assess the intensity and interference of the pain. Results: The number of subjects who returned the questionnaire was 1084 (76.5%). The prevalence of frequent pain in the preceding week was 50% among women without diabetes and 63% among women with diabetes (adjusted, p = 0.22). In men, the corresponding proportions were 42% without diabetes and 47% with diabetes (adjusted, p = 0.58). In both genders, depressive symptoms and the number of comorbidities were associated with pain experienced more often than once a week and with daily pain. Diabetes was not associated with pain intensity or pain interference in either women or men. Conclusions: Pain in older adults is associated with depressive symptoms and the number of comorbidities more than with diabetes itself.Peer reviewe
Parameter estimators of random intersection graphs with thinned communities
This paper studies a statistical network model generated by a large number of
randomly sized overlapping communities, where any pair of nodes sharing a
community is linked with probability via the community. In the special case
with the model reduces to a random intersection graph which is known to
generate high levels of transitivity also in the sparse context. The parameter
adds a degree of freedom and leads to a parsimonious and analytically
tractable network model with tunable density, transitivity, and degree
fluctuations. We prove that the parameters of this model can be consistently
estimated in the large and sparse limiting regime using moment estimators based
on partially observed densities of links, 2-stars, and triangles.Comment: 15 page
New insights into the environmental factors controlling the ground thermal regime across the Northern Hemisphere : a comparison between permafrost and non-permafrost areas
The thermal state of permafrost affects Earth surface systems and human activity in the Arctic and has implications for global climate. Improved understanding of the local-scale variability in the global ground thermal regime is required to account for its sensitivity to changing climatic and geoecological conditions. Here, we statistically related observations of mean annual ground temperature (MAGT) and active-layer thickness (ALT) to high-resolution (similar to 1 km(2)) geospatial data of climatic and local environmental conditions across the Northern Hemisphere. The aim was to characterize the relative importance of key environmental factors and the magnitude and shape of their effects on MAGT and ALT. The multivariate models fitted well to both response variables with average R-2 values being similar to 0.94 and 0.78. Corresponding predictive performances in terms of root-mean-square error were similar to 1.31 degrees C and 87 cm. Freezing (FDD) and thawing (TDD) degree days were key factors for MAGT inside and outside the permafrost domain with average effect sizes of 6.7 and 13.6 degrees C, respectively. Soil properties had marginal effects on MAGT (effect size = 0.4-0.7 degrees C). For ALT, rainfall (effect size = 181 cm) and solar radiation (161 cm) were most influential. Analysis of variable importance further underlined the dominance of climate for MAGT and highlighted the role of solar radiation for ALT. Most response shapes for MAGTPeer reviewe
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