383 research outputs found
Massive Complex Scalar Field in a Kerr-Sen Black Hole Background: Exact Solution of Wave Equation and Hawking Radiation
The separated radial part of a massive complex scalar wave equation in the
Kerr-Sen geometry is shown to satisfy the generalized spheroidal wave equation
which is, in fact, a confluent Heun equation up to a multiplier. The Hawking
evaporation of scalar particles in the Kerr-Sen black hole background is
investigated by the Damour-Ruffini-Sannan's method. It is shown that quantum
thermal effect of the Kerr-Sen black hole has the same characteras that of the
Kerr-Newman black hole.Comment: Revtex, 5 pages, no figure, submitted to Phys. Rev.
Anomalous shell effect in the transition from a circular to a triangular billiard
We apply periodic orbit theory to a two-dimensional non-integrable billiard
system whose boundary is varied smoothly from a circular to an equilateral
triangular shape. Although the classical dynamics becomes chaotic with
increasing triangular deformation, it exhibits an astonishingly pronounced
shell effect on its way through the shape transition. A semiclassical analysis
reveals that this shell effect emerges from a codimension-two bifurcation of
the triangular periodic orbit. Gutzwiller's semiclassical trace formula, using
a global uniform approximation for the bifurcation of the triangular orbit and
including the contributions of the other isolated orbits, describes very well
the coarse-grained quantum-mechanical level density of this system. We also
discuss the role of discrete symmetry for the large shell effect obtained here.Comment: 14 pages REVTeX4, 16 figures, version to appear in Phys. Rev. E.
Qualities of some figures are lowered to reduce their sizes. Original figures
are available at http://www.phys.nitech.ac.jp/~arita/papers/tricirc
Predictors of Burden in Carers of Patients with Impulse Control Behaviors in Parkinson's Disease
Background: Impulse control behaviors (ICBs) are problematic, reward-based behaviors, affecting 15% to 35% of patients with Parkinson's disease. Evidence exists of increased carer burden as a result of these behaviors; however, little is known about the variables mediating this effect and their management. Objective: To identify factors predictive of carer burden in a cohort of patients with Parkinson's disease with ICBs to enable the development of targeted therapeutic interventions for carers. Methods: Data were collected from 45 patients with clinically significant ICBs and their carers, including levodopa equivalent daily dosage, motor and neuropsychiatric symptoms, cognitive function, and ICB severity. Carer burden was quantified by Zarit Burden Interview (ZBI). Univariate analyses were performed using the Spearman rank correlation. Linear regression was used to create a multivariate model for predicting ZBI. Results: Univariate analysis identified significant correlations between ZBI and patient total Neuropsychiatric Inventory (NPI) (rs = 0.50), 4 NPI subscores (agitation/aggression, rs = 0.41; depression/dysphoria, rs = 0.47; apathy/indifference, rs = 0.49; and irritability/lability, rs = 0.38; all P < 0.02), and the carer 28-item General Health Questionnaire (GHQ-28) (rs = 0.52, P < 0.0005). Multivariate linear regression retained total NPI and GHQ-28 scores and were collectively predictive of 36.6% of the variance in the ZBI. Conclusions: Our study suggests that depressive symptoms and aspects of executive dysfunction (apathy and disinhibition) in the patient are potential drivers of carer burden in patients with ICBs. Such findings suggest the presence of executive difficulties and/or mood disturbance should point the clinician to inquire about burden in the caring role and encourage the carer to seek help for any of their own general health problems, which may compound carer burden
Dyonic dilaton black holes
The properties of static spherically symmetric black holes, which are both
electrically and magnetically charged, and which are coupled to the dilaton in
the presence of a cosmological constant, Lambda, are considered. It is shown
that apart from the Reissner-Nordstrom-de Sitter solution with constant
dilaton, such solutions do not exist if Lambda > 0 (in arbitrary spacetime
dimension >=4 ). However, asymptotically anti-de Sitter dyonic black hole
solutions with a non-trivial dilaton do exist if Lambda < 0. Both these
solutions and the asymptotically flat (Lambda = 0) solutions are studied
numerically for arbitrary values of the dilaton coupling parameter, g_0, in
four dimensions. The asymptotically flat solutions are found to exhibit two
horizons if g_0 = 0, 1, \sqrt{3}, \sqrt{6}, ..., \sqrt{n(n+1)/2},..., and one
horizon otherwise. For asymptotically anti-de Sitter solutions the result is
similar, but the corresponding values of g_0 are altered in a non-linear
fashion which depends on Lambda and the mass and charges of the black holes.
All dyonic solutions with Lambda <= 0 are found to have zero Hawking
temperature in the extreme limit, however, regardless of the value of g_0.Comment: 24 pages, phyzzx, epsf, 7 in-text figures. Small addition to
introduction, and a few extra reference
A Possible Crypto-Superconducting Structure in a Superconducting Ferromagnet
We have measured the dc and ac electrical and magnetic properties in various
magnetic fields of the recently reported superconducting ferromagnet
RuSr2GdCu2O8. Our reversible magnetization measurements demonstrate the absence
of a bulk Meissner state in the compound below the superconducting transition
temperature. Several scenarios that might account for the absence of a bulk
Meissner state, including the possible presence of a sponge-like non-uniform
superconducting or a crypto-superconducting structure in the chemically uniform
Ru-1212, have been proposed and discussed.Comment: 8 pages, 5 PNG figures, submitted to Proceedings of the 9th Japan-US
Workshop on High-Tc Superconductors, Yamanashi, Japan, October 13-15, 1999;
accepted for publication in Physica C (December 24, 1999
Independent Loop Invariants for 2+1 Gravity
We identify an explicit set of complete and independent Wilson loop
invariants for 2+1 gravity on a three-manifold , with
a compact oriented Riemann surface of arbitrary genus . In the
derivation we make use of a global cross section of the -principal
bundle over Teichm\"uller space given in terms of Fenchel-Nielsen coordinates.Comment: 11pp, 2 figures (postscript, compressed and uu-encoded), TeX,
Pennsylvania State University, CGPG-94/7-
Use of traditional serological methods and oral fluids to assess immunogenicity in children aged 2-16Â years after successive annual vaccinations with LAIV.
BACKGROUND: The UK introduced quadrivalent live attenuated influenza vaccine (qLAIV) for children in 2013/2014. The impact of annual vaccination on effectiveness and immunogenicity is being assessed. METHOD: A phase III/IV open-label study of the immunogenicity of annual vaccination with qLAIV (Fluenzâą) was conducted over three consecutive years (2014/15-2016/17) in 254, 249 and 162 children respectively. Serum responses to vaccine components were measured by Haemagglutination Inhibition (HAI) and anti-A(H1N1)pdm09 Neuraminidase (NAI) assays, stratified according to previous receipt of AS03B-adjuvanted A(H1N1)pdm09 pandemic vaccine in 2009/10. Antibody levels to the A(H1N1)pdm09 and H3N2 vaccine components in oral fluids (OF) were explored using an ELISA. FINDINGS: More paired pre- and post-vaccination oral fluids (96%) than paired sera (87%) were obtained. Geometric mean titre rises using HAI assays were limited, with maximum rises seen in year one for both influenza B strains when 39% and 43% of subjects seroconverted (95% confidence interval 33-46% and 36-50%, respectively) and year two for influenza H3N2, when 40% (33-46%) individuals seroconverted. Prior pandemic vaccine receipt resulted in higher pre- and post-vaccination A(H1N1)pdm09 HAI titres and lower pre-and post-vaccination NAI (N1 neuraminidase) titres in all three years. OF results were congruent with HAI results; assay specificity compared to HAI was 88.1 and 71.6 percent, and sensitivity was 86.4 and 74.8 percent respectively for A(H1N1)pdm09 and H3N2. CONCLUSION: In all three study years, vaccination with qLAIV resulted in poor antibody responses. However, OFs are an alternative specimen type that allows self sampling, can easily be obtained from children, and their analysis leads to similar conclusions as classic serology by HAI. Their suitability for seroprevalence studies should be investigated. We demonstrated a sustained effect from prior receipt of the AS03B-adjuvanted A(H1N1)pdm09 vaccine, even after repeat vaccination with qLAIV indicating that early exposure to influenza antigens has a significant long lasting effect
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