QUANTUM CORRECTIONS AND EXTREMAL BLACK HOLES

We consider static solutions of two dimensional dilaton gravity models as toy laboratories to address the question of the final fate of black holes. A non perturbative correction to the CGHS potential term is shown to lead classically to an extremal black hole geometry, thus providing a plausible solution to Hawking evaporation paradox. However, the full quantum theory does not admit an extremal solution.Comment: 12 pages, LaTex, no figures. We have improved the main argument leading to the non-existence of an extremal black hole in the quantum theor

Flaxino dark matter and stau decay

If the spontaneous breaking of Peccei-Quinn symmetry comes from soft supersymmetry breaking, the fermionic partners of the symmetry-breaking fields have mass of order the gravitino mass, and are called flatinos. The lightest flatino, called here the flaxino, is a CDM candidate if it is the lightest supersymmetric particle. We here explore flaxino dark matter assuming that the lightest ordinary supersymmetric particle is the stau, with gravity-mediated supersymmetry breaking. The decay of the stau to the flaxino is fast enough not to spoil the standard predictions of Big Bang Nucleosynthesis, and its track and decay can be seen in future colliders.Comment: 9 pages, 4 figures, to appear in JHE

An automated software system to promote anticoagulation and reduce stroke risk: cluster-randomized controlled trial

Background and Purpose: Oral anticoagulants (OAC) substantially reduce risk of stroke in atrial fibrillation, but uptake is suboptimal. Electronic health records enable automated identification of people at risk but not receiving treatment. We investigated the effectiveness of a software tool (AURAS-AF [Automated Risk Assessment for Stroke in Atrial Fibrillation]) designed to identify such individuals during routine care through a cluster-randomized trial.Methods: Screen reminders appeared each time the electronic health records of an eligible patient was accessed until a decision had been taken over OAC treatment. Where OAC was not started, clinicians were prompted to indicate a reason. Control practices continued usual care. The primary outcome was the proportion of eligible individuals receiving OAC at 6 months. Secondary outcomes included rates of cardiovascular events and reports of adverse effects of the software on clinical decision-making.Results: Forty-seven practices were randomized. The mean proportion–prescribed OAC at 6 months was 66.3% (SD=9.3) in the intervention arm and 63.9% (9.5) in the control arm (adjusted difference 1.21% [95% confidence interval −0.72 to 3.13]). Incidence of recorded transient ischemic attack was higher in the intervention practices (median 10.0 versus 2.3 per 1000 patients with atrial fibrillation; P=0.027), but at 12 months, we found a lower incidence of both all cause stroke (P=0.06) and hemorrhage (P=0.054). No adverse effects of the software were reported.Conclusions: No significant change in OAC prescribing occurred. A greater rate of diagnosis of transient ischemic attack (possibly because of improved detection or overdiagnosis) was associated with a reduction (of borderline significance) in stroke and hemorrhage over 12 months.Clinical Trial Registration: URL: http://www.isrctn.com. Unique Identifier: ISRCTN55722437.%U http://stroke.ahajournals.org/content/strokeaha/early/2017/01/24/STROKEAHA.116.015468.full.pd

Barriers to a software reminder system for risk assessment of stroke in atrial fibrillation: a process evaluation of a cluster randomised trial in general practice

Background: Oral anticoagulants reduce the risk of stroke in patients with atrial fibrillation (AF), but are underused. AURAS-AF (AUtomated Risk Assessment for Stroke in AF) is a software tool designed to identify eligible patients and promote discussions within consultations about initiating anticoagulants.Aim: To investigate the implementation of the software in UK general practice.Design and setting: Process evaluation involving 23 practices randomly allocated to use AURAS-AF during a cluster randomised trial.Method: An initial invitation to discuss anticoagulation was followed by screen reminders appearing during consultations until a decision had been made. The reminders required responses, giving reasons for cases where an anticoagulant was not initiated. Qualitative interviews with clinicians and patients explored acceptability and usability.Results: In a sample of 476 patients eligible for the invitation letter, only 159 (33.4%) were considered suitable for invitation by their GPs. Reasons given were frequently based on frailty, and risk of falls or haemorrhage. Of those invited, 35 (22%) started an anticoagulant (7.4% of those originally identified). A total of 1695 main-screen reminders occurred in 940 patients. In 883 instances, the decision was taken not to initiate and a range of reasons offered. Interviews with 15 patients and seven clinicians indicated that the intervention was acceptable, though the issue of disruptive screen reminders was raised.Conclusion: Automated risk assessment for stroke in atrial fibrillation and prompting during consultations are feasible and generally acceptable, but did not overcome concerns about frailty and risk of haemorrhage as barriers to anticoagulant uptake

A polygenic and phenotypic risk prediction for polycystic ovary syndrome evaluated by phenomewide association studies

Context: As many as 75% of patients with polycystic ovary syndrome (PCOS) are estimated tobe unidentified in clinical practice. Objective: Utilizing polygenic risk prediction, we aim to identify the phenome-widecomorbidity patterns characteristic of PCOS to improve accurate diagnosis and preventivetreatment.Design, Patients, and Methods: Leveraging the electronic health records (EHRs) of 124 852individuals, we developed a PCOS risk prediction algorithm by combining polygenic risk scores(PRS) with PCOS component phenotypes into a polygenic and phenotypic risk score (PPRS). Weevaluated its predictive capability across different ancestries and perform a PRS-based phenomewide association study (PheWAS) to assess the phenomic expression of the heightened risk ofPCOS.Results: The integrated polygenic prediction improved the average performance (pseudo-R2)for PCOS detection by 0.228 (61.5-fold), 0.224 (58.8-fold), 0.211 (57.0-fold) over the null modelacross European, African, and multi-ancestry participants respectively. The subsequent PRSpowered PheWAS identified a high level of shared biology between PCOS and a range ofmetabolic and endocrine outcomes, especially with obesity and diabetes: "morbid obesity","type 2 diabetes", "hypercholesterolemia", "disorders of lipid metabolism", "hypertension",and "sleep apnea" reaching phenome-wide significance.Conclusions: Our study has expanded the methodological utility of PRS in patient stratificationand risk prediction, especially in a multifactorial condition like PCOS, across different geneticorigins. By utilizing the individual genome-phenome data available from the EHR, our approachalso demonstrates that polygenic prediction by PRS can provide valuable opportunities todiscover the pleiotropic phenomic network associated with PCOS pathogenesis.Abbreviations: AA, African ancestry; ANOVA, analysis of variance; BMI, body mass index; EA,European ancestry; EHR, electronic health records; eMERGE, electronic Medical Records andGenomics Network; GWAS, genome-wide association study; IBD, identity-by-descent; ICDCM, International Classification of Diseases, Clinical Modification; LD, linkage disequilibrium;MA, multi-ancestry; MAF, minor allele frequency; NIH, National Institutes of Health; PCA,principal component analysis; PheWAS, phenome-wide association study; PCOS, polycysticovary syndrome; PPRS, polygenic and phenotypic risk score; PRS, polygenic risk sc

High resolution diffusion imaging in the unfixed post-mortem infant brain at 7T

Diffusion MRI of the infant brain allows investigation of the organizational structure of maturing fibers during brain development. Post-mortem imaging has the potential to achieve high resolution by using long scan times, enabling precise assessment of small structures. Technical development for post-mortem diffusion MRI has primarily focused on scanning of fixed tissue, which is robust to effects like temperature drift that can cause unfixed tissue to degrade. The ability to scan unfixed tissue in the intact body would enable post-mortem studies without organ donation, but poses new technical challenges. This paper describes our approach to scan setup, protocol optimization, and tissue protection in the context of the Developing Human Connectome Project (dHCP) of neonates. A major consideration was the need to preserve the integrity of unfixed tissue during scanning in light of energy deposition at ultra-high magnetic field strength. We present results from one of the first two subjects recruited to the study, who died on postnatal day 46 at 29+6 weeks postmenstrual age, demonstrating high-quality diffusion MRI data. We find altered diffusion properties consistent with post-mortem changes reported previously. Preliminary voxel-wise and tractography analyses are presented with comparison to age-matched in vivo dHCP data. These results show that high-quality, high-resolution post-mortem data of unfixed tissue can be acquired to explore the developing human brain

Quality indicators for patients with traumatic brain injury in European intensive care units

Background: The aim of this study is to validate a previously published consensus-based quality indicator set for the management of patients with traumatic brain injury (TBI) at intensive care units (ICUs) in Europe and to study its potential for quality measur