2,119 research outputs found
Symmetric Criticality for Tight Knots
We prove a version of symmetric criticality for ropelength-critical knots.
Our theorem implies that a knot or link with a symmetric representative has a
ropelength-critical configuration with the same symmetry. We use this to
construct new examples of ropelength critical configurations for knots and
links which are different from the ropelength minima for these knot and link
types.Comment: This version adds references, and most importantly an
acknowledgements section which should have been in the original postin
The untilted diffuse matter Bianchi V Universe
A diffuse matter filled Type V Universe is studied. The anisotropic
behaviour, the distortion caused to the CMBR and the parameter region allowed
by present cosmological bounds are examined. It is shown how the overall sky
pattern of temperature anisotropies changes under a non-infinitesimal spatial
coordinate transformation that preserves the Type V manifest homogeneity.Comment: (RevTeX) 23 pages, 2 figures, to appear in Physics Letters
How Anisotropic is our Universe?
Large-scale cosmic microwave background anisotropies in homogeneous, globally
anisotropic cosmologies are investigated. We perform a statistical analysis in
which the four-year data from the Cosmic Background Explorer satellite is
searched for the specific anisotropy patterns predicted by these models and
thereby set definitive upper limits on the amount of shear, and
vorticity, , which are orders of magnitude stronger than previous
constraints. We comment on how these results might impact our understanding of
primordial global anisotropy.Comment: 12 pages (1 figure), uses RevTex and psfig, submitted to PR
Two real parton contributions to non-singlet kernels for exclusive QCD DGLAP evolution
Results for the two real parton differential distributions needed for
implementing a next-to-leading order (NLO) parton shower Monte Carlo are
presented. They are also integrated over the phase space in order to provide
solid numerical control of the MC codes and for the discussion of the
differences between the standard factorization and Monte Carlo
implementation at the level of inclusive NLO evolution kernels. Presented
results cover the class of non-singlet diagrams entering into NLO kernels. The
classic work of Curci-Furmanski-Pertonzio was used as a guide in the
calculations.Comment: 34 pages, 3 figure
Cardiogenic shock complicating acute myocardial infarction: The use of coronary angioplasty and the integration of the new support devices into patient management
Conventional therapy for cardiogenic shock complicating acute myocardial infarction continues to be associated with a high in-hospital mortality rate. Hemodynamic support with new mechanical devices and emergency coronary revascularization may alter the long-term prognosis for patients with this complication. Between July 1985 and March 1990, 68 patients presented to the University of Michigan with acute myocardial infarction and cardiogenic shock. Interventions performed included thrombolytic therapy (46%), intraaortic balloon pump counterpulsation (70%), cardiac catheterization (86%), coronary angioplasty (73%), emergency coronary artery bypass grafting/ventricular septal defect repair (15%), Hemopump insertion (11%), percutaneous cardiopulmonary support (4%) and ventricular assist device (3%).The 30-day survival rate was significantly better in patients who had successful angioplasty of the infarct-related artery than in patients with failed angioplasty (61% vs. 7%, p = 0.002) or no attempt at angioplasty (61% vs. 14%, p = 0.003). This difference was maintained over the 1-year follow-up period. The only clinical variable that predicted survival was age <65 years.The early use of the new support devices in 10 patients was associated with death in 8 (80%), but this poor outcome may reflect a selection bias for an especially high risk population. Collectively, these recent data continue to suggest that emergency revascularization with angioplasty may reduce the mortality rate, but further study is required to define optimal utilization and integration of new support devices
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