7,789 research outputs found
The incidence of sudden unexpected death in epilepsy (sudep) in south dublin and wicklow
Patients with epilepsy have a mortality rate higher than that of the general population. Some of this excess mortality is attributable to sudden unexpected death (SUDEP). We examined the incidence of this phenomenon both retrospectively and prospectively in the population of South Dublin and Wicklow over the period May 1992–1995. Cases were ascertained by examination of post-mortem registers of hospitals serving the area studied. Information on cases was sought from hospital records, general practitioners and families. Fifteen cases (10 male, five female) were identified resulting in an overall incidence rate of SUDEP of 1:680/year for the 3 years of the study. This is the only study of incidence of SUDEP conducted in Ireland and our results are in keeping with incidence rates elsewhere in Europe and the USA
Effects of temperature upon the collapse of a Bose-Einstein condensate in a gas with attractive interactions
We present a study of the effects of temperature upon the excitation
frequencies of a Bose-Einstein condensate formed within a dilute gas with a
weak attractive effective interaction between the atoms. We use the
self-consistent Hartree-Fock Bogoliubov treatment within the Popov
approximation and compare our results to previous zero temperature and
Hartree-Fock calculations The metastability of the condensate is monitored by
means of the excitation frequency. As the number of atoms in the
condensate is increased, with held constant, this frequency goes to zero,
signalling a phase transition to a dense collapsed state. The critical number
for collapse is found to decrease as a function of temperature, the rate of
decrease being greater than that obtained in previous Hartree-Fock
calculations.Comment: 4 pages LaTeX, 3 eps figures. To appear as a letter in J. Phys.
POB5 A MODELLED COST-EFFECTIVENESS EVALUATION OF SIBUTRAMINE THERAPY IN A HIGH RISK OBESE POPULATION
2017 McDonald diagnostic criteria: A review of the evidence
The diagnosis of Multiple Sclerosis (MS) has continuously evolved, allowing for an earlier and more accurate diagnosis of MS over time. The McDonald Criteria for diagnosis of MS were originally proposed in 2001, with previous revisions in both 2005 and 2010. The International Panel on Diagnosis in MS have recently reviewed the 2010 McDonald Criteria, and made recommendations for the revised 2017 McDonald Criteria. Any revisions made relied entirely on the available evidence, and not expert opinion. In this review, we provide an overview of the recent 2017 revisions to the McDonald Criteria, focusing in particular on the motivating evidence behind the recommendations made. We also review the existing research around misdiagnosis in MS, as well as areas considered to be high priorities of research, currently lacking in sufficient evidence, which may influence future diagnostic criteria in years to come. Finally, we illustrate some clinical examples, to demonstrate the impact of new diagnostic criteria on time to MS diagnosis in a real-world setting
Bivariate -distribution for transition matrix elements in Breit-Wigner to Gaussian domains of interacting particle systems
Interacting many-particle systems with a mean-field one body part plus a
chaos generating random two-body interaction having strength , exhibit
Poisson to GOE and Breit-Wigner (BW) to Gaussian transitions in level
fluctuations and strength functions with transition points marked by
and , respectively; . For these systems theory for matrix elements of one-body transition
operators is available, as valid in the Gaussian domain, with , in terms of orbitals occupation numbers, level densities and an
integral involving a bivariate Gaussian in the initial and final energies. Here
we show that, using bivariate -distribution, the theory extends below from
the Gaussian regime to the BW regime up to . This is well
tested in numerical calculations for six spinless fermions in twelve single
particle states.Comment: 7 pages, 2 figure
Gapless finite- theory of collective modes of a trapped gas
We present predictions for the frequencies of collective modes of trapped
Bose-condensed Rb atoms at finite temperature. Our treatment includes a
self-consistent treatment of the mean-field from finite- excitations and the
anomolous average. This is the first gapless calculation of this type for a
trapped Bose-Einstein condensed gas. The corrections quantitatively account for
the downward shift in the excitation frequencies observed in recent
experiments as the critical temperature is approached.Comment: 4 pages Latex and 2 postscript figure
Health professionals’ and coroners’ views on less invasive perinatal and paediatric autopsy: a qualitative study
OBJECTIVE: To assess health professionals’ and coroners’ attitudes towards non-minimally and minimally invasive autopsy in the perinatal and paediatric setting. METHODS: A qualitative study using semistructured interviews. Data were analysed thematically. RESULTS: Twenty-five health professionals (including perinatal/paediatric pathologists and anatomical pathology technologists, obstetricians, fetal medicine consultants and bereavement midwives, intensive care consultants and family liaison nurses, a consultant neonatologist and a paediatric radiologist) and four coroners participated. Participants viewed less invasive methods of autopsy as a positive development in prenatal and paediatric care that could increase autopsy rates. Several procedural and psychological benefits were highlighted including improved diagnostic accuracy in some circumstances, potential for faster turnaround times, parental familiarity with imaging and laparoscopic approaches, and benefits to parents and faith groups who object to invasive approaches. Concerns around the limitations of the technology such not reaching the same levels of certainty as full autopsy, unsuitability of imaging in certain circumstances, the potential for missing a diagnosis (or misdiagnosis) and de-skilling the workforce were identified. Finally, a number of implementation issues were raised including skills and training requirements for pathologists and radiologists, access to scanning equipment, required computational infrastructure, need for a multidisciplinary approach to interpret results, cost implications, equity of access and acceptance from health professionals and hospital managers. CONCLUSION: Health professionals and coroners viewed less invasive autopsy as a positive development in perinatal and paediatric care. However, to inform implementation a detailed health economic analysis and further exploration of parental views, particularly in different religious groups, are required
A Gapless Theory of Bose-Einstein Condensation in Dilute Gases at Finite Temperature
In this paper we develop a gapless theory of BEC which can be applied to both
trapped and homogeneous gases at zero and finite temperature. The many-body
Hamiltonian for the system is written in a form which is approximately
quadratic with higher order cubic and quartic terms. The quadratic part is
diagonalized exactly by transforming to a quasiparticle basis, while the
non-quadratic terms are dealt with using first and second order perturbation
theory. The conventional treatment of these terms, based on factorization
approximations, is shown to be inconsistent.
Infra-red divergences can appear in individual terms of the perturbation
expansion, but we show analytically that the total contribution beyond
quadratic order is finite. The resulting excitation spectrum is gapless and the
energy shifts are small for a dilute gas away from the critical region,
justifying the use of perturbation theory. Ultra-violet divergences can appear
if a contact potential is used to describe particle interactions. We show that
the use of this potential as an approximation to the two-body T-matrix leads
naturally to a high-energy renormalization.
The theory developed in this paper is therefore well-defined at both low and
high energy and provides a systematic description of Bose-Einstein condensation
in dilute gases. It can therefore be used to calculate the energies and decay
rates of the excitations of the system at temperatures approaching the phase
transition.Comment: 39 pages of Revtex. 1 figur
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