5,504 research outputs found
Decision making processes in people with symptoms of acute myocardial infarction: qualitative study
Objective To identify, the themes that influence decision making processes used by patients with symptoms of acute myocardial infarction. Design Qualitative study using semistructured interviews. Setting Two district hospitals in North Yorkshire. Participants 22 patients admitted to hospital with confirmed second, third, or fourth acute myocardial infarction. Main outcome measure Patients' perceptions of their experience between the onset of symptoms and the decision to seek medical help. Results Six main themes that influence the decision making process were identified: appraisal of In symptoms, perceived risk, previous experience, psychological and emotional factors, use of the NHS, and context of the event. Conclusions Knowledge of symptoms may not be enough to promote prompt action in the event of an acute myocardial infarction. Cognitive and emotional processes, individual beliefs and values, and the influence of the context of the event should also be considered in individual interventions designed to reduce delay in the event of symptoms of acute myocardial infarction
Non-perturbative embedding of local defects in crystalline materials
We present a new variational model for computing the electronic first-order
density matrix of a crystalline material in presence of a local defect. A
natural way to obtain variational discretizations of this model is to expand
the difference Q between the density matrix of the defective crystal and the
density matrix of the perfect crystal, in a basis of precomputed maximally
localized Wannier functions of the reference perfect crystal. This approach can
be used within any semi-empirical or Density Functional Theory framework.Comment: 13 pages, 4 figure
Evaluation of a ln tan integral arising in quantum field theory
We analytically evaluate a dilogarithmic integral that is prototypical of
volumes of ideal tetrahedra in hyperbolic geometry. We additionally obtain new
representations of the Clausen function Cl_2 and the Catalan constant
G=Cl_2(\pi/2), as well as new relations between sine and Clausen function
values.Comment: 24 pages, no figure
Modeling of Isotropic Backward-Wave Materials Composed of Resonant Spheres
A possibility to realize isotropic artificial backward-wave materials is
theoretically analyzed. An improved mixing rule for the effective permittivity
of a composite material consisting of two sets of resonant dielectric spheres
in a homogeneous background is presented. The equations are validated using the
Mie theory and numerical simulations. The effect of a statistical distribution
of sphere sizes on the increasing of losses in the operating frequency band is
discussed and some examples are shown.Comment: 15 pages, 7 figure
The Nature of the Giant Outbursts in the Bursting Pulsar GRO J 1744-28
We investigate the possible role of an accretion disk instability in
producing the giant outbursts seen in GRO J1744-28. Specifically, we study the
global, time dependent evolution of the Lightman-Eardley instability which can
develop near the inner edge of an accretion disk when the radiation pressure
becomes comparable to the gas pressure. Broadly speaking, our results are
compatible with earlier works by Taam \& Lin and by Lasota \& Pelat. The
uniqueness of GRO J1744-28 appears to be associated with the constraint that,
in order for outbursts to occur, the rate of accretion at the inner edge must
be within a narrow range just above the critical accretion rate at which
radiation pressure is beginning to become significant.Comment: 11 pages in .tex file, 4 Postscript figures, .tex file uses
aasms.sty; Ap. J. L. 1996, in pres
Vortex pinning by a columnar defect in planar superconductors with point disorder
We study the effect of a single columnar pin on a dimensional array
of vortex lines in planar type II superconductors in the presence of point
disorder. In large samples, the pinning is most effective right at the
temperature of the vortex glass transition. In particular, there is a
pronounced maximum in the number of vortices which are prevented from tilting
by the columnar defect in a weak transverse magnetic field. Using
renormalization group techniques we show that the columnar pin is irrelevant at
long length scales both above and below the transition, but due to very
different mechanisms. This behavior differs from the disorder-free case, where
the pin is relevant in the low temperature phase. Solutions of the
renormalization equations in the different regimes allow a discussion of the
crossover between the pure and disordered cases. We also compute density
oscillations around the columnar pin and the response of these oscillations to
a weak transverse magnetic field.Comment: 12 pages, 5 figures, minor typos corrected, a new reference adde
Simulation of the Directional Dark Matter Detector (D3) and Directional Neutron Observer (DiNO)
Preliminary simulation and optimization studies of the Directional Dark
Matter Detector and the Directional Neutron Observer are presented. These
studies show that the neutron interaction with the gas-target in these
detectors is treated correctly by GEANT4 and that by lowering the pressure, the
sensitivity to low-mass WIMP candidates is increased. The use of negative ion
drift might allow us to search the WIMP mass region suggested by the results of
the non-directional experiments DAMA/LIBRA, CoGeNT and CRESST-II.Comment: Proceedings of the 3rd International conference on Directional
Detection of Dark Matter (CYGNUS 2011), Aussois, France, 8-10 June 201
Orthogonal Polynomial Representation of Imaginary-Time Green's Functions
We study the expansion of single-particle and two-particle imaginary-time
Matsubara Green's functions of quantum impurity models in the basis of Legendre
orthogonal polynomials. We discuss various applications within the dynamical
mean-field theory (DMFT) framework. The method provides a more compact
representation of the Green's functions than standard Matsubara frequencies and
therefore significantly reduces the memory-storage size of these quantities.
Moreover, it can be used as an efficient noise filter for various physical
quantities within the continuous-time quantum Monte Carlo impurity solvers
recently developed for DMFT and its extensions. In particular, we show how to
use it for the computation of energies in the context of realistic DMFT
calculations in combination with the local density approximation to the density
functional theory (LDA+DMFT) and for the calculation of lattice
susceptibilities from the local irreducible vertex function.Comment: 14 pages, 11 figure
Association between match activity variables, measures of fatigue and neuromuscular performance capacity following elite competitive soccer matches
The aim of the study was to assess the relationships between match activity variables, subsequent fatigue and neuromuscular performance capacity in elite soccer players. Subjects (n = 10) were professional soccer players participating in the English Championships. Match activity variables and markers of fatigue status were measured before and following two matches. Creatine kinase (CK) and muscle soreness were measured at baseline, immediately following, as well as 40 and 64 h post-match. Countermovement jump performance and perceived ratings of wellness were measured at baseline, then 40 and 64 h post-match. Relationships were shown between CK and the total number of accelerations and decelerations immediately (r = 0.63; large), 40 h (r = 0.45; moderate) and 64 h post-match (r = 0.35; moderate) (p < 0.05). Relationships between CK and total sprint distance (r = 0.39; moderate) and the number of sprints (r = 0.35; moderate) 40 h post-match (p < 0.05) were observed. Furthermore, relationships were shown between the perceived rating of wellness and number of accelerations 40 (r = 0.52; large) and 64 h (r = 0.40; moderate) post-match, sprint distance 40 h post-match (r = 0.40; moderate) and the total number of sprints 40 h post-match (r = 0.51; large) (p < 0.05). The quantification of match activity variables, particularly the total number of accelerations and decelerations and the number of sprints, provides insights into the fatigue status in elite soccer players 40 and 64 h post-match
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