5,419 research outputs found
The British film industry: creativity and constraint
An article on the potential impact of the changes to film policy, culture and infrastructure in light of significant changes in 2010-11
Cosmological Bounds on Spatial Variations of Physical Constants
We derive strong observational limits on any possible large-scale spatial
variation in the values of physical 'constants' whose space-time evolution is
driven by a scalar field. The limits are imposed by the isotropy of the
microwave background on large angular scales in theories which describe space
and time variations in the fine structure constant, the electron-proton mass
ratio, and the Newtonian gravitational constant, G. Large-scale spatial
fluctuations in the fine structure constant are bounded by 2x10^-9 and
1.2x10^-8 in the BSBM and VSL theories respectively, fluctuations in the
electron-proton mass ratio by 9x10^-5 in the BM theory and fluctuations in G by
3.6x10^-10 in Brans-Dicke theory. These derived bounds are significantly
stronger than any obtainable by direct observations of astrophysical objects at
the present time.Comment: 13 pages, 1 table, typos corrected, refs added. Published versio
The Andante Regime of Scalar Field Dynamics
The andante regime of scalar field dynamics in the chaotic inflationary
Universe is defined as the epoch when the field is rolling moderately slowly
down its interaction potential, but at such a rate that first-order corrections
to the slow-roll approximation become important. These conditions should apply
towards the end of inflation as the field approaches the global minimum of the
potential. Solutions to the Einstein-scalar field equations for the class of
power law potentials are found in this regime in
terms of the inverse error function.Comment: 11 pages of plain Latex, FNAL-Pub-94/226-
Observable Effects of Scalar Fields and Varying Constants
We show by using the method of matched asymptotic expansions that a
sufficient condition can be derived which determines when a local experiment
will detect the cosmological variation of a scalar field which is driving the
spacetime variation of a supposed constant of Nature. We extend our earlier
analyses of this problem by including the possibility that the local region is
undergoing collapse inside a virialised structure, like a galaxy or galaxy
cluster. We show by direct calculation that the sufficient condition is met to
high precision in our own local region and we can therefore legitimately use
local observations to place constraints upon the variation of "constants" of
Nature on cosmological scales.Comment: Invited Festscrift Articl
Systematic review of hospital readmissions in stroke patients
Background Previous evidence on factors and causes of readmissions associated with high-impact users of stroke is scanty. The aim of the study was to investigate common causes and pattern of short- and long-term readmissions stroke patients by conducting a systematic review of studies using hospital administrative data. Common risk factors associated with the change of readmission rate were also examined. Methods The literature search was conducted from 15th February to 15th March 2016 using various databases, such as Medline, Embase, and Web of Science. Results There were total of 24 studies (n=2,126,617) included in the review. Only 4 studies assessed causes of readmissions in stroke patients with the follow-up duration from 30 days to 5 years. Common causes of readmissions in majority of the studies were recurrent stroke, infections and cardiac conditions. Common patient-related risk factors associated with increased readmission rate were age and history of coronary heart disease, heart failure, renal disease, respiratory disease, peripheral arterial disease and diabetes. Among stroke-related factors, length of stay of index stroke admission was associated with increased readmission rate, followed by bowel incontinence, feeding tube and urinary catheter. Conclusion Although risk factors and common causes of readmission were identified, but none of the previous studies investigated causes and their sequence of readmissions among high-impact stroke users
Tilted String Cosmologies
Global symmetries of the string effective action are employed to generate
tilted, homogeneous Bianchi type VI_h string cosmologies from a previously
known stiff perfect fluid solution to Einstein gravity. The dilaton field is
not constant on the surfaces of homogeneity. The future asymptotic state of the
models is interpreted as a plane wave and is itself an exact solution to the
string equations of motion to all orders in the inverse string tension. An
inhomogeneous generalization of the Bianchi type III model is also found.Comment: 9 pages, Standard Latex Source. To appear in Physics Letters B Minor
change: Authors now alphabetically liste
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