349 research outputs found
Magnetic monopole clusters, and monopole dominance after smoothing in the maximally Abelian gauge of SU(2)
In the maximally Abelian gauge of SU(2), the clusters of monopole current are
found to divide into two distinct classes. The largest cluster permeates the
lattice, has a density that scales and produces the string tension. The
remaining clusters possess an approximate 1/l^3 number density distribution (l
is the cluster length), their radii vary as \sqrt l and their total current
density does not scale. Their contribution to the string tension is compatible
with being exactly zero. Their number density can be thought of as arising from
an underlying scale invariant distribution. This suggests that they are not
related to instantons. We also observe that when we locally smoothen the SU(2)
fields by cooling, the string tension due to monopoles becomes much smaller
than the SU(2) string tension. This dramatic loss of Abelian/monopole dominance
occurs even after just one cooling step.Comment: Talk presented at LATTICE97(topology). LaTeX, with 4 PS figure
Monopoles, confinement and the photon propagator in QED
We study the lattice gauge boson propagator of 3D compact QED in Landau gauge
at zero and non-zero temperature. Non-perturbative effects are reflected by the
generation of a mass , by an anomalous dimension and by the photon
wave function renormalisation . These effects can be attributed to
monopoles: they are absent in the propagator of the regular part of the gauge
field. The r\^ole of Gribov copies is carefully investigated.Comment: 3 pages, 5 figures, Lattice2002(topology
Fermi surface of an important nano-sized metastable phase: AlLi
Nanoscale particles embedded in a metallic matrix are of considerable
interest as a route towards identifying and tailoring material properties. We
present a detailed investigation of the electronic structure, and in particular
the Fermi surface, of a nanoscale phase ( AlLi) that has so far been
inaccessible with conventional techniques, despite playing a key role in
determining the favorable material properties of the alloy (Al\nobreakdash-9
at. %\nobreakdash-Li). The ordered precipitates only form within the
stabilizing Al matrix and do not exist in the bulk; here, we take advantage of
the strong positron affinity of Li to directly probe the Fermi surface of
AlLi. Through comparison with band structure calculations, we demonstrate
that the positron uniquely probes these precipitates, and present a 'tuned'
Fermi surface for this elusive phase
Large Loops of Magnetic Current and Confinement in Four Dimensional Lattice Gauge Theory
We calculate the heavy quark potential from the magnetic current due to
monopoles in four dimensional lattice gauge theory. The magnetic current
is found from link angle configurations using the DeGrand-Toussaint
identification method. The link angle configurations are generated in a cosine
action simulation on a lattice. The magnetic current is resolved into
large loops which wrap around the lattice and simple loops which do not.
Wrapping loops are found only in the confined phase. It is shown that the long
range part of the heavy quark potential, in particular the string tension, can
be calculated solely from the large, wrapping loops of magnetic current.Comment: 15 pages (Latex file plus 3 postscript files appended), Univeristy of
Illinois Preprint ILL-(TH)-93-\#1
The string tension in the maximally Abelian gauge after smoothing
We apply smoothing to SU(2) lattice field configurations in 3+1 dimensions
before fixing to the maximally Abelian gauge. The Abelian projected string
tension is shown to be stable under this, whilst the monopole string tension
declines by O(30%). Blocking of the SU(2) fields reduces this effect, but the
use of extended monopole definitions does not. We discuss these results in the
context of additional confining excitations in the U(1) vacuum.Comment: LATTICE98(confine
Persistence of an outbreak of gonorrhoea with high-level resistance to azithromycin in England, November 2014‒May 2018
Between November 2014 and May 2018, 118 laboratory-confirmed cases of high-level azithromycin resistant Neisseria gonorrhoeae were identified in England. Cases emerged among heterosexuals in Leeds but spread across England and into sexual networks of men who have sex with men as the outbreak progressed. The few epidemiological links identified indicate substantial under-diagnosis of cases and this, along with the upturn in cases in 2017, highlights the difficulties in controlling the outbreak
Peritoneal dialysis in children after cardiopulmonary bypass
AbstractObjective: We reviewed 5 years' experience with peritoneal dialysis in children with acute renal failure after cardiac operations. We hypothesized that peritoneal dialysis is safe and effective in children with low-output cardiac failure after cardiac operations. Results: Mortality in these patients with renal failure (n = 32) was 46.9%. Fluid removed by peritoneal dialysis was 48 ± 28 ml/kg per 24 hours. Most complications of peritoneal dialysis were minor, hyperglycemia being the most frequent (53.1%). Peritoneal infection was suspected in 25%. Bowel perforation developed in two patients. None of the complications required early termination of dialysis. Hemodynamics and pulmonary function improved continuously during the study period. Conclusion: The early institution of peritoneal dialysis in acute renal failure and low cardiac output after cardiac operations not only removes fluid, thus easing fluid restriction, but may also improve cardiopulmonary function(J Thorac Cardiovasc Surg 1997;113:64-70
Long-term interleukin-6 levels and subsequent risk of coronary heart disease: Two new prospective studies and a systematic review
Background
The relevance to coronary heart disease (CHD) of cytokines that govern inflammatory cascades, such as interleukin-6 (IL-6), may be underestimated because such mediators are short acting and prone to fluctuations. We evaluated associations of long-term circulating IL-6 levels with CHD risk (defined as nonfatal myocardial infarction [MI] or fatal CHD) in two population-based cohorts, involving serial measurements to enable correction for within-person variability. We updated a systematic review to put the new findings in context.
Methods and Findings
Measurements were made in samples obtained at baseline from 2,138 patients who had a first-ever nonfatal MI or died of CHD during follow-up, and from 4,267 controls in two cohorts comprising 24,230 participants. Correction for within-person variability was made using data from repeat measurements taken several years apart in several hundred participants. The year-to-year variability of IL-6 values within individuals was relatively high (regression dilution ratios of 0.41, 95% confidence interval [CI] 0.28-0.53, over 4 y, and 0.35, 95% CI 0.23-0.48, over 12 y). Ignoring this variability, we found an odds ratio for CHD, adjusted for several established risk factors, of 1.46 (95% CI 1.29-1.65) per 2 standard deviation (SD) increase of baseline IL-6 values, similar to that for baseline C-reactive protein. After correction for within-person variability, the odds ratio for CHD was 2.14 (95% CI 1.45-3.15) with long-term average ("usual'') IL-6, similar to those for some established risk factors. Increasing IL-6 levels were associated with progressively increasing CHD risk. An updated systematic review of electronic databases and other sources identified 15 relevant previous population-based prospective studies of IL-6 and clinical coronary outcomes (i.e., MI or coronary death). Including the two current studies, the 17 available prospective studies gave a combined odds ratio of 1.61 (95% CI 1.42-1.83) per 2 SD increase in baseline IL-6 (corresponding to an odds ratio of 3.34 [95% CI 2.45-4.56] per 2 SD increase in usual [long-term average] IL-6 levels).
Conclusions
Long-term IL-6 levels are associated with CHD risk about as strongly as are some major established risk factors, but causality remains uncertain. These findings highlight the potential relevance of IL-6-mediated pathways to CH
String Tension from Monopoles in SU(2) Lattice Gauge Theory
The axis for Figure 2 was wrong. It has been fixed and the postscript file
replaced (The file was called comp.ps).Comment: (22 pages latex (revtex); 2 figures appended as postscript files -
search for mono.ps and comp.ps. Figures mailed on request--send a note to
[email protected]) Preprint ILL-(TH)-94-#1
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