2,326 research outputs found
Direct numerical computation of disorder parameters
In the framework of various statistical models as well as of mechanisms for
color confinement, disorder parameters can be developed which are generally
expressed as ratios of partition functions and whose numerical determination is
usually challenging. We develop an efficient method for their computation and
apply it to the study of dual superconductivity in 4d compact U(1) gauge
theory.Comment: 5 pages, 6 figures. Final revised version published in PR
Fermionization, Convergent Perturbation Theory, and Correlations in the Yang-Mills Quantum Field Theory in Four Dimensions
We show that the Yang-Mills quantum field theory with momentum and spacetime
cutoffs in four Euclidean dimensions is equivalent, term by term in an
appropriately resummed perturbation theory, to a Fermionic theory with nonlocal
interaction terms. When a further momentum cutoff is imposed, this Fermionic
theory has a convergent perturbation expansion. To zeroth order in this
perturbation expansion, the correlation function of generic components
of pairs of connections is given by an explicit, finite-dimensional integral
formula, which we conjecture will behave as \noindent for where is a positive integer depending
on the gauge group In the case where we conjecture that \noindent so that the rate
of decay of correlations increases as Comment: Minor corrections of notation, style and arithmetic errors;
correction of minor gap in the proof of Proposition 1.4 (the statement of the
Proposition was correct); further remark and references adde
Holidaying with the family pet: No dogs allowed!
This paper assesses the extent to which dog owners located in Brisbane, Australia, wish to holiday with their pets, and whether there is a gap between this desire and reality. The paper also examines the extent to which this demand is being catered for by the tourism accommodation sector. The need for this study reflects the increasingly significant role dogs are playing in the lives of humans, and the scale
of the dog-owning population. The results suggest that, although there is a strong desire among dog owners to take holidays with their pets, the actualisation of this
desire is comparatively low. A significant obstacle to the realisation of this desire appears to be a dearth of pet-friendly accommodation. This has implications for the
ability of the tourism industry to benefit from this potentially lucrative market, that is, the dog-owning population
The Logarithmic Triviality of Compact QED Coupled to a Four Fermi Interaction
This is the completion of an exploratory study of Compact lattice Quantum
Electrodynamics with a weak four-fermi interaction and four species of massless
fermions. In this formulation of Quantum Electrodynamics massless fermions can
be simulated directly and Finite Size Scaling analyses can be performed at the
theory's chiral symmetry breaking critical point. High statistics simulations
on lattices ranging from to yield the equation of state, critical
indices, scaling functions and cumulants. The measurements are well fit with
the orthodox hypothesis that the theory is logarithmically trivial and its
continuum limit suffers from Landau's zero charge problem.Comment: 27 pages, 15 figues and 10 table
Coherent phenomena in mesoscopic systems
A mesoscopic system of cylindrical geometry made of a metal or a
semiconductor is shown to exhibit features of a quantum coherent state. It is
shown that magnetostatic interaction can play an important role in mesoscopic
systems leading to an ordered ground state. The temperature below the
system exhibits long-range order is determined. The self-consistent mean field
approximation of the magnetostatic interaction is performed giving the
effective Hamiltonian from which the self-sustaining currents can be obtained.
The relation of quantum coherent state in mesoscopic cylinders to other
coherent systems like superconductors is discussed.Comment: REVTeX, 4 figures, in print in Supercond. Sci. Techno
The effects of incisional bupivacaine infusions on postoperative opioid consumption and pain scores after total abdominal hysterectomy
Background: The aim of this study was to determine opioid requirements and pain intensity scores in patients after a total abdominal hysterectomy (TAH) administered with a bupivacaine infusion for a 30-hour period, and then to compare the data with that of a control group. Method: This was a prospective, parallel, single-blinded randomised trial which took place at the Rahima Moosa Mother and Child Hospital, Johannesburg. Thirty-six consenting patients, who underwent a TAH, were randomised to either having a 0.39% bupivacaine infusion in the incisional site or not. Morphine was administered via a patient-controlled analgesia pump (PCA) for rescue analgesia. Dynamic, static and worst pain scores were assessed one, six and 30 hours after surgery by using a visual analogue scale (VAS). Morphine consumption was recorded at set intervals. Results: There were statistically significant differences between the two groups’ dynamic VAS scores in the first hour and at 24 hours and 30 hours; in the static VAS score in the first hour; and in the VAS scores for the worst pain experienced since the patients were last seen in the first hour and six hours after the operation. There was no statistical difference between the two groups’ opioid consumption at all set observation points. Conclusion: The opioid requirements of the two groups were comparable, although participants who had the bupivacaine infusion experienced reduced pain intensity which lasted until six hours postoperatively, and also had reduced pain intensity when moving around 30 hours after the operation.Keywords: incisional bupivacaine infusions, total abdominal hysterectomy, postoperative pain contro
Microbiology and atmospheric processes: Biological, physical and chemical characterization of aerosol particles
The interest in bioaerosols has traditionally been linked to health hazards for humans, animals and plants. However, several components of bioaerosols exhibit physical properties of great significance for cloud processes, such as ice nucleation and cloud condensation. To gain a better understanding of their influence on climate, it is therefore important to determine the composition, concentration, seasonal fluctuation, regional diversity and evolution of bioaerosols. In this paper, we will review briefly the existing techniques for detection, quantification, physical and chemical analysis of biological particles, attempting to bridge physical, chemical and biological methods for analysis of biological particles and integrate them with aerosol sampling techniques. We will also explore some emerging spectroscopy techniques for bulk and single-particle analysis that have potential for in-situ physical and chemical analysis. Lastly, we will outline open questions and further desired capabilities (e. g., in-situ, sensitive, both broad and selective, on-line, time-resolved, rapid, versatile, cost-effective techniques) required prior to comprehensive understanding of chemical and physical characterization of bioaerosols
Effect of Surface Patterning and Presence of Collagen I on the Phenotypic Changes of Embryonic Stem Cell Derived Cardiomyocytes
Embryonic stem cell derived cardiomyocytes have been widely investigated for stem cell therapy or in vitro model systems. This study examines how two specific biophysical stimuli, collagen I and cell alignment, affect the phenotypes of embryonic stem cell derived cardiomyocytes in vitro. Three phenotypic indicators are assessed: sarcomere organization, cell elongation, and percentage of binucleation. Murine embryonic stem cells were differentiated in a hanging drop assay and cardiomyocytes expressing GFP-α-actinin were isolated by fluorescent sorting. First, the effect of collagen I was investigated. Addition of soluble collagen I markedly reduced binucleation as a result of an increase in cytokinesis. Laden with a collagen gel layer, myocyte mobility and cell shape change were impeded. Second, the effect of cell alignment by microcontact printing and nanopattern topography was investigated. Both patterning techniques induced cell alignment and elongation. Microcontact printing of 20 μm line pattern accelerated binucleation and nanotopography with 700 nm ridges and 3.5 μm grooves negatively regulated binucleation. This study highlights the importance of biophysical cues in the morphological changes of differentiated cardiomyocytes and may have important implications on how these cells incorporate into the native myocardium.Singapore-MIT Alliance for Research and TechnologyNational Science Foundation (U.S.) ((Science and Technology Center (EBICS): Emergent Behaviors of Integrated Cellular Systems, Grant CBET-0939511)Charles Stark Draper Laboratory (Internal Research and Development Program
Composition of the Innermost Core Collapse Supernova Ejecta
With presently known input physics and computer simulations in 1D, a
self-consistent treatment of core collapse supernovae does not yet lead to
successful explosions, while 2D models show some promise. Thus, there are
strong indications that the delayed neutrino mechanism works combined with a
multi-D convection treatment for unstable layers. On the other hand there is a
need to provide correct nucleosynthesis abundances for the progressing field of
galactic evolution and observations of low metallicity stars. The innermost
ejecta is directly affected by the explosion mechanism, i.e. most strongly the
yields of Fe-group nuclei for which an induced piston or thermal bomb treatment
will not provide the correct yields because the effect of neutrino interactions
is not included. We apply parameterized variations to the neutrino scattering
cross sections and alternatively, parameterized variations are applied to the
neutrino absorption cross sections on nucleons in the ``gain region''. We find
that both measures lead to similar results, causing explosions and a Ye>0.5 in
the innermost ejected layers, due to the combined effect of a short weak
interaction time scale and a negligible electron degeneracy, unveiling the
proton-neutron mass difference. We include all weak interactions (electron and
positron capture, beta-decay, neutrino and antineutrino capture on nuclei, and
neutrino and antineutrino capture on nucleons) and present first
nucleosynthesis results for these innermost ejected layers to discuss how they
improve predictions for Fe-group nuclei. The proton-rich environment results in
enhanced abundances of 45Sc, 49Ti, and 64Zn as requested by chemical evolution
studies and observations of low metallicity stars as well as appreciable
production of nuclei in the mass range up to A=80.Comment: 13 pages, 8 figures. Final versio
Cohort study on the effects of everyday life radio frequency electromagnetic field exposure on non-specific symptoms and tinnitus
BACKGROUND: There is public concern regarding potential health effects of radio frequency electromagnetic fields (RF-EMF) exposure, as produced by mobile phones or broadcast transmitters. The objective of this study was to investigate the association between RF-EMF exposure and non-specific symptoms and tinnitus in a prospective cohort study. METHODS: In 2008, 1375 randomly selected participants from Basel, Switzerland, were enrolled in a questionnaire survey with follow-up after one year (participation rate 82%). A score for somatic complaints (von Zerssen list) and headache (HIT-6) was assessed. Far-field environmental RF-EMF exposure was predicted using a validated prediction model. Regarding near-field exposure, self-reported mobile and cordless phone use as well as mobile phone operator data were collected. In multivariate regression models, we investigated whether exposure at baseline (cohort analysis) or changes in exposure between baseline and follow-up (change analysis) were related to changes in health scores. RESULTS: For participants in the top decile of environmental far-field RF-EMF exposure at baseline, in comparison to participants exposed below the median value, the change in the von Zerssen- and HIT-6-scores between baseline and follow-up was -0.12 (95%-CI: -1.79 to 1.56) and -0.37 (95%-CI: -1.80 to 1.07) units, respectively. Exposure to near-field sources and a change in exposure between baseline and follow-up were not related to non-specific symptoms. Similarly, no association between RF-EMF exposure and tinnitus was observed. CONCLUSIONS: In this first cohort study using objective and well-validated RF-EMF exposure measures, we did not observe an association between RF-EMF exposure and non-specific symptoms or tinnitu
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