Inclination-dependent spectral and timing properties in transient black hole X-ray binaries

We use a simple one-dimensional parameterisation of timing properties to show that hard and hard-intermediate state transient black hole X-ray binaries with the same power-spectral shape have systematically harder X-ray power-law emission in higher-inclination systems. We also show that the power-spectral shape and amplitude of the broadband noise (with low-frequency quasi-periodic oscillations, QPOs, removed) is independent of inclination, confirming that it is well-correlated with the intrinsic structure of the emitting regions and that the "type C" QPO, which is inclination-dependent, has a different origin to the noise, probably geometric. Our findings suggest that the power-law emission originates in a corona which is flattened in the plane of the disc, and not in a jet-like structure which would lead to softer spectra at higher inclinations. However, there is tentative evidence that the inclination-dependence of spectral shape breaks down deeper into the hard state. This suggests either a change in the coronal geometry and possible evidence for contribution from jet emission, or alternatively an even more optically thin flow in these states.Comment: 6 Pages, 4 Figures, accepted as a Letter by MNRA

Power-Colours: Simple X-ray Binary Variability Comparison

We demonstrate a new method of variability classification using observations of black hole X-ray binaries. Using `power colours' -- ratios of integrated power in different Fourier frequency bands -- we can clearly differentiate different canonical black hole states as the objects evolve during outburst. We analyse (~ 2400) Rossi X-ray Timing Explorer observations of 12 transient low mass black hole X-ray binaries and find that the path taken around the power colour-colour diagram as the sources evolve is highly consistent from object to object. We discuss how the consistency observed in the power colour-colour diagram between different objects allows for easy state classification based on only a few observations, and show how the power-spectral shapes can be simply classified using a single parameter, the power-spectral `hue'. To illustrate the benefits of our simple model-independent approach, we show that the persistent high mass X-ray binary Cyg X-1 shows very similar power-spectral evolution to the transient black hole sources, with the main difference being caused by a combination of a lack of quasi-periodic oscillations and an excess of low-frequency power-law noise in the Cyg X-1 power spectra during the transitional state. We also compare the transient objects to the neutron star atoll source Aquila X-1, demonstrating that it traces a different path in the power colour-colour plot. Thus, power-colours could be an effective method to classify newly discovered X-ray binaries.Comment: 13 pages, 9 figures, accepted by MNRA

Alien Registration- Burlock, Uttley L. (Houlton, Aroostook County)

https://digitalmaine.com/alien_docs/36112/thumbnail.jp

The Ubiquity of the rms-flux relation in Black Hole X-ray Binaries

We have investigated the short term linear relation between the rms variability and the flux in 1,961 observations of 9 black hole X-ray binaries. The rms-flux relation for the 1-10 Hz range is ubiquitously observed in any observation with good variability signal to noise (> 3 % 1-10 Hz fractional rms). This concurs with results from a previous study of Cygnus X-1 (Gleissner et. al. 2004), and extends detection of the rms-flux relation to a wider range of states. We find a strong dependence of the flux intercept of the rms-flux relation on source state; as the source transitions from the hard state into the hard intermediate state the intercept becomes strongly positive. We find little evidence for flux dependence of the broad-band noise within the PSD shape, excepting a small subset of observations from one object in an anomalous soft-state. We speculate that the ubiquitous linear rms-flux relation in the broad band noise of this sample, representing a range of different states and objects, indicates that its formation mechanism is an essential property of the luminous accretion flow around black holes.Comment: 12 pages, 6 figures, accepted for publication in MNRA

Erratum to: The clinical and cost effectiveness of group art therapy for people with non-psychotic mental health disorders: a systematic review and cost-effectiveness analysis.

Background The majority of mental health problems are non-psychotic (e.g., depression, anxiety, and phobias). For some people, art therapy may be a more acceptable alternative form of psychological therapy than standard forms of treatment, such as talking therapies. This study was part of a health technology assessment commissioned by the National Institute for Health Research, UK and aimed to systematically appraise the clinical and cost-effective evidence for art therapy for people with non-psychotic mental health disorders. Methods Comprehensive literature searches for studies examining art therapy in populations with non-psychotic mental health disorders were performed in May 2013. A quantitative systematic review of clinical effectiveness and a systematic review of studies evaluating the cost-effectiveness of group art therapy were conducted. Results Eleven randomised controlled trials were included (533 patients). Meta-analysis was not possible due to clinical heterogeneity and insufficient comparable data on outcome measures across studies. The control groups varied between studies but included: no treatment/wait-list, attention placebo controls and psychological therapy comparators. Art therapy was associated with significant positive changes relative to the control group in mental health symptoms in 7 of the 11 studies. A de novo model was constructed and populated with data identified from the clinical review. Scenario analyses were conducted allowing comparisons of group art therapy with wait-list control and group art therapy with group verbal therapy. Group art-therapy appeared cost-effective compared with wait-list control with high certainty although generalisability to the target population was unclear; group verbal therapy appeared more cost-effective than art therapy but there was considerable uncertainty and a sizeable probability that art therapy was more cost effective. Conclusions From the limited available evidence art therapy was associated with positive effects compared with control in a number of studies in patients with different clinical profiles. The included trials were generally of poor quality and are therefore likely to be at high risk of bias. Art therapy appeared to be cost-effective versus wait-list but further studies are needed to confirm this finding in the target population. There was insufficient evidence to make an informed comparison of the cost-effectiveness of group art therapy with group verbal therapy. Trial registration HTA project no. 12/27/16; PROSPERO registration no. CRD42013003957

An adaptive-binning method for generating constant-uncertainty/constant-significance light curves with Fermi-LAT data

We present a method enabling the creation of constant-uncertainty/constant-significance light curves with the data of the Fermi-Large Area Telescope (LAT). The adaptive-binning method enables more information to be encapsulated within the light curve than with the fixed-binning method. Although primarily developed for blazar studies, it can be applied to any sources. This method allows the starting and ending times of each interval to be calculated in a simple and quick way during a first step. The reported mean flux and spectral index (assuming the spectrum is a power-law distribution) in the interval are calculated via the standard LAT analysis during a second step. The absence of major caveats associated with this method has been established by means of Monte-Carlo simulations. We present the performance of this method in determining duty cycles as well as power-density spectra relative to the traditional fixed-binning method.Comment: 17 pages, 13 figures, 5 tables. Submitted to A&

Creutzfeldt-Jakob disease: a systematic review of global incidence, prevalence, infectivity, and incubation

Creutzfeldt-Jakob disease (CJD) is a fatal disease presenting with rapidly progressive dementia, and most patients die within a year of clinical onset. CJD poses a potential risk of iatrogenic transmission, as it can incubate asymptomatically in humans for decades before becoming clinically apparent. In this Review, we sought evidence to understand the current iatrogenic risk of CJD to public health by examining global evidence on all forms of CJD, including clinical incidence and prevalence of subclinical disease. We found that although CJD, particularly iatrogenic CJD, is rare, the incidence of sporadic CJD is increasing. Incubation periods as long as 40 years have been observed, and all genotypes have now been shown to be susceptible to CJD. Clinicians and surveillance programmes should maintain awareness of CJD to mitigate future incidences of its transmission. Awareness is particularly relevant for sporadic CJD, which occurs in older people in whom clinical presentation could resemble rapidly developing dementia

Interventions to reduce the risk of surgically transmitted Creutzfeldt–Jakob disease: a cost-effective modelling review

Background Creutzfeldt–Jakob disease is a fatal neurological disease caused by abnormal infectious proteins called prions. Prions that are present on surgical instruments cannot be completely deactivated; therefore, patients who are subsequently operated on using these instruments may become infected. This can result in surgically transmitted Creutzfeldt–Jakob disease. Objective To update literature reviews, consultation with experts and economic modelling published in 2006, and to provide the cost-effectiveness of strategies to reduce the risk of surgically transmitted Creutzfeldt–Jakob disease. Methods Eight systematic reviews were undertaken for clinical parameters. One review of cost-effectiveness was undertaken. Electronic databases including MEDLINE and EMBASE were searched from 2005 to 2017. Expert elicitation sessions were undertaken. An advisory committee, convened by the National Institute for Health and Care Excellence to produce guidance, provided an additional source of information. A mathematical model was updated focusing on brain and posterior eye surgery and neuroendoscopy. The model simulated both patients and instrument sets. Assuming that there were potentially 15 cases of surgically transmitted Creutzfeldt–Jakob disease between 2005 and 2018, approximate Bayesian computation was used to obtain samples from the posterior distribution of the model parameters to generate results. Heuristics were used to improve computational efficiency. The modelling conformed to the National Institute for Health and Care Excellence reference case. The strategies evaluated included neither keeping instruments moist nor prohibiting set migration; ensuring that instruments were kept moist; prohibiting instrument migration between sets; and employing single-use instruments. Threshold analyses were undertaken to establish prices at which single-use sets or completely effective decontamination solutions would be cost-effective. Results A total of 169 papers were identified for the clinical review. The evidence from published literature was not deemed sufficiently strong to take precedence over the distributions obtained from expert elicitation. Forty-eight papers were identified in the review of cost-effectiveness. The previous modelling structure was revised to add the possibility of misclassifying surgically transmitted Creutzfeldt–Jakob disease as another neurodegenerative disease, and assuming that all patients were susceptible to infection. Keeping instruments moist was estimated to reduce the risk of surgically transmitted Creutzfeldt–Jakob disease cases and associated costs. Based on probabilistic sensitivity analyses, keeping instruments moist was estimated to on average result in 2.36 (range 0–47) surgically transmitted Creutzfeldt–Jakob disease cases (across England) caused by infection occurring between 2019 and 2023. Prohibiting set migration or employing single-use instruments reduced the estimated risk of surgically transmitted Creutzfeldt–Jakob disease cases further, but at considerable cost. The estimated costs per quality-adjusted life-year gained of these strategies in addition to keeping instruments moist were in excess of £1M. It was estimated that single-use instrument sets (currently £350–500) or completely effective cleaning solutions would need to cost approximately £12 per patient to be cost-effective using a £30,000 per quality-adjusted life-year gained value. Limitations As no direct published evidence to implicate surgery as a cause of Creutzfeldt–Jakob disease has been found since 2005, the estimations of potential cases from elicitation are still speculative. A particular source of uncertainty was in the number of potential surgically transmitted Creutzfeldt–Jakob disease cases that may have occurred between 2005 and 2018. Conclusions Keeping instruments moist is estimated to reduce the risk of surgically transmitted Creutzfeldt–Jakob disease cases and associated costs. Further surgical management strategies can reduce the risks of surgically transmitted Creutzfeldt–Jakob disease but have considerable associated costs. Study registration This study is registered as PROSPERO CRD42017071807. Funding This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 11. See the NIHR Journals Library website for further project information