Quantum healing of classical singularities in power-law spacetimes

We study a broad class of spacetimes whose metric coefficients reduce to powers of a radius r in the limit of small r. Among these four-parameter "power-law" metrics we identify those parameters for which the spacetimes have classical singularities as r approaches 0. We show that a large set of such classically singular spacetimes is nevertheless nonsingular quantum mechanically, in that the Hamiltonian operator is essentially self-adjoint, so that the evolution of quantum wave packets lacks the ambiguity associated with scattering off singularities. Using these metrics, the broadest class yet studied to compare classical with quantum singularities, we explore the physical reasons why some that are singular classically are "healed" quantum mechanically, while others are not. We show that most (but not all) of the remaining quantum-mechanically singular spacetimes can be excluded if either the weak energy condition or the dominant energy condition is invoked, and we briefly discuss the effect of this work on the strong cosmic censorship hypothesis.Comment: 14 pages, 1 figure; extensive revision

Quantum singularity of Levi-Civita spacetimes

Quantum singularities in general relativistic spacetimes are determined by the behavior of quantum test particles. A static spacetime is quantum mechanically singular if the spatial portion of the wave operator is not essentially self-adjoint. Here Weyl's limit point-limit circle criterion is used to determine whether a wave operator is essentially self-adjoint. This test is then applied to scalar wave packets in Levi-Civita spacetimes to help elucidate the physical properties of the spacetimes in terms of their metric parameters

Late-Time Behavior of Stellar Collapse and Explosions: I. Linearized Perturbations

Problem with the figures should be corrected. Apparently a broken uuencoder was the cause.Comment: 16pp, RevTex, 6 figures (included), NSF-ITP-93-8

Mortality among patients with polymyalgia rheumatica: A retrospective cohort study.

OBJECTIVE: To determine whether a diagnosis of polymyalgia rheumatica (PMR) is associated with premature mortality. METHODS: We extracted anonymised electronic medical records of patients over the age of 40 years, who were eligible for linkage with the Office for National Statistics (ONS) Death Registration dataset, from the Clinical Practice Research Datalink from 1990-2016. Patients with PMR were individually matched by age, sex and registered General Practice with up to 5 controls without PMR. The total number and proportion of deaths and mortality rates were calculated. The mortality rate ratio (MRR), with 95% confidence interval (CI), adjusted for age, sex, region, smoking status, body mass index (BMI), and alcohol consumption, was calculated using Poisson regression. The twenty most common causes of death were tabulated. RESULTS: 18,943 patients with PMR were matched to 87,801 controls. Mean (standard deviation) follow-up after date of diagnosis was 8.0 (4.4) years in patients with PMR, and 7.9 (4.6) in controls. PMR was not associated with an increase in the risk of death (adjusted MRR 1.00 [95% CI 0.97, 1.03]) compared to matched controls. Causes of death were broadly similar between patients with PMR and controls, although patients with PMR were slightly more likely to have a vascular cause of death recorded (24% vs 23%). CONCLUSIONS: A diagnosis with PMR does not appear to increase the risk of premature death. Minor variations in cause of death were observed, but overall this study is reassuring for patients with PMR and clinicians

Classical and quantum properties of a 2-sphere singularity

Recently Boehmer and Lobo have shown that a metric due to Florides, which has been used as an interior Schwarzschild solution, can be extended to reveal a classical singularity that has the form of a two-sphere. Here the singularity is shown to be a scalar curvature singularity that is both timelike and gravitationally weak. It is also shown to be a quantum singularity because the Klein-Gordon operator associated with quantum mechanical particles approaching the singularity is not essentially self-adjoint.Comment: 10 pages, 1 figure, minor corrections, final versio

11C-metomidate PET-CT scanning can identify aldosterone-producing adenomas after unsuccessful lateralisation with CT/MRI and adrenal venous sampling.

Primary hyperaldosteronism, characterised by hypertension and hypokalaemia, is a syndrome caused by aldosterone excess most commonly from either a unilateral aldosterone-producing adenoma or bilateral adrenal hyperplasia. Subtype classification can be challenging with cross-sectional imaging and even with interventional radiological techniques such as adrenal venous sampling. Imaging with 11C-metomidate positron emission tomography-computed tomography (PET-CT) is an emerging tool that facilitates functional characterisation and potentially successful surgical intervention of aldosterone-producing adenomas. This technique has highlighted that, although unilateral adenomas and bilateral hyperplasia represent opposite ends of the disease spectrum, a relatively common intermediate phenotype exists of unilateral/bilateral multinodular disease

What is the impact of giant cell arteritis on patients' lives?: a UK qualitative study

Objectives: Clinical management of giant cell arteritis (GCA) involves balancing the risks and burdens arising from the disease with those arising from treatment, but there is little research on the nature of those burdens. We aimed to explore the impact of giant cell arteritis (GCA) and its treatment on patients’ lives. Methods: UK patients with GCA participated in semi-structured telephone interviews. Inductive thematic analysis was employed. Results: 24 participants were recruited (age: 65–92 years, time since diagnosis: 2 months to >6 years). The overarching themes from analysis were: ongoing symptoms of the disease and its treatment; and ‘life-changing’ impacts. The overall impact of GCA on patients’ lives arose from a changing combination of symptoms, side effects, adaptations to everyday life and impacts on sense of normality. Important factors contributing to loss of normality were glucocorticoid-related treatment burdens and fear about possible future loss of vision. Conclusions: The impact of GCA in patients’ everyday lives can be substantial, multifaceted and ongoing despite apparent control of disease activity. The findings of this study will help doctors better understand patient priorities, legitimise patients’ experiences of GCA and work with patients to set realistic treatment goals and plan adaptations to their everyday lives