Concurrent estimation of noise and compact-binary signal parameters in gravitational-wave data

Gravitational-wave parameter estimation for compact binary signals typically relies on sequential estimation of the properties of the detector Gaussian noise and of the binary parameters. This procedure assumes that the noise variance, expressed through its power spectral density, is perfectly known in advance. We assess the impact of this approximation on the estimated parameters by means of an analysis that simultaneously estimates the noise and compact binary parameters, thus allowing us to marginalize over uncertainty in the noise properties. We compare the traditional sequential estimation method and the new full marginalization method using events from the GWTC-3 catalog. We find that the recovered signals and inferred parameters agree to within their statistical measurement uncertainty. At current detector sensitivities, uncertainty about the noise power spectral density is a subdominant effect compared to other sources of uncertainty.Comment: 10 pages, 9 figure

Accurate characterization of the stochastic gravitational-wave background with pulsar timing arrays by likelihood reweighting

An isotropic stochastic background of nanohertz gravitational waves creates excess residual power in pulsar-timing-array datasets, with characteristic inter-pulsar correlations described by the Hellings-Downs function. These correlations appear as nondiagonal terms in the noise covariance matrix, which must be inverted to obtain the pulsar-timing-array likelihood. Searches for the stochastic background, which require many likelihood evaluations, are therefore quite computationally expensive. We propose a more efficient method: we first compute approximate posteriors by ignoring cross correlations, and then reweight them to exact posteriors via importance sampling. We show that this technique results in accurate posteriors and marginal likelihood ratios, because the approximate and exact posteriors are similar, which makes reweighting especially accurate. The Bayes ratio between the marginal likelihoods of the exact and approximate models, commonly used as a detection statistic, is also estimated reliably by our method, up to ratios of at least $10^6$.Comment: 9 pages, 4 figure

Global Aviation Monitor (GAM) - December 2017

Objective The development, delivery and evaluation of a training programme for medical and nursing professionals on best practice for informing families of their child’s disability. Design A 2 h training course on ‘Best practice guidelines for informing families of their child’s disability’ was designed based on the findings of a nationally representative study of parents and professionals. The classroom-based course comprised a presentation of the research and recommendations of the best practice guidelines; a DVD film of parent stories and professional advice; group discussion; and a half-hour input from a parent of two children with disabilities. An anonymous, pretraining and post-training questionnaire was administered to measure knowledge and confidence levels, using scales adapted from a study by Ferguson et al (2006). Participants 235 participants, including medical students, nursing students, and junior hospital doctors (JHDs). Outcome measures Knowledge of best practice and confidence in communicating diagnosis of disability. Results Significant improvements in knowledge (time 1 mean (M)=14.31, SD=2.961; time 2 M=18.17, SD=3.068) and confidence (time 1 M=20.87, SD=5.333; time 2 M=12.43, SD=3.803) following training were found. In addition, a significant interaction between time and cohort (medical students, nurses and JHDs) was found for knowledge. Further examination suggested medical students’ knowledge was developing to the extent that post-training, their scores were higher than nurses, but not significantly different to JHDs. Conclusions The increase in reported levels of knowledge and confidence following training in best practice for informing families of their child’s disability indicates the potential for providing communication skills training in this area.Participation of EM Bettendorf in this project was funded by the Mental Health/Developmental Disabilities Grant (NIMH/NIH R25 MH071286) at Children’s Hospital Boston (Dr K Munir, PI). Funding for the wider pilot project of which the current study forms a part, was provided by the Health Services National Partnership Forum and the National Federation of Voluntary Bodies Providing Services to People with Intellectual Disabilities.peer-reviewe

The curious case of GW200129: interplay between spin-precession inference and data-quality issues

Measurement of spin-precession in black hole binary mergers observed with gravitational waves is an exciting milestone as it relates to both general relativistic dynamics and astrophysical binary formation scenarios. In this study, we revisit the evidence for spin-precession in GW200129 and localize its origin to data in LIGO Livingston in the 20--50\,Hz frequency range where the signal amplitude is lower than expected from a non-precessing binary given all the other data. These data are subject to known data quality issues as a glitch was subtracted from the detector's strain data. The lack of evidence for spin-precession in LIGO Hanford leads to a noticeable inconsistency between the inferred binary mass ratio and precessing spin in the two LIGO detectors, something not expected from solely different Gaussian noise realizations. We revisit the LIGO Livingston glitch mitigation and show that the difference between a spin-precessing and a non-precessing interpretation for GW200129 is smaller than the statistical and systematic uncertainty of the glitch subtraction, finding that the support for spin-precession depends sensitively on the glitch modeling. We also investigate the signal-to-noise ratio $\sim7$ trigger in the less sensitive Virgo detector. Though not influencing the spin-precession studies, the Virgo trigger is grossly inconsistent with the ones in LIGO Hanford and LIGO Livingston as it points to a much heavier system. We interpret the Virgo data in the context of further data quality issues. While our results do not disprove the presence of spin-precession in GW200129, we argue that any such inference is contingent upon the statistical and systematic uncertainty of the glitch mitigation. Our study highlights the role of data quality investigations when inferring subtle effects such as spin-precession for short signals such as the ones produced by high-mass systems.Comment: 17 pages, 14 figures, 2 tables. Data release: https://zenodo.org/record/725965

Geography in Ireland

There are certain critical periods of time when various aspects of development come into alignment. Now is such a time in Ireland and more, perhaps, than any other discipline or perspective, geography and geographers are well-placed to help make sense of what is happening in the island of Ireland – politically, economically, culturally and environmentally. The island of Ireland constitutes two political entities – The Republic of Ireland comprising the bulk of the landmass and 3.9 million peo..

A 24-h helpline for access to expert management advice for food allergy-related anaphylaxis in children: protocol for a pragmatic randomised controlled trial

OBJECTIVES: Anaphylaxis is an important, potentially life-threatening paediatric emergency. It is responsible for considerable morbidity and, in some cases, death. Poor outcomes may be associated with an inability to differentiate between milder and potentially more severe reactions and an associated reluctance to administer self-injectable adrenaline. This study aims to assess the effectiveness of a 24-h telephone access to specialist paediatric allergy expert advice in improving the quality of life of children and their families with potentially life-threatening food allergy (ie, anaphylaxis) compared with usual clinical care. METHODS AND ANALYSIS: Children aged less than 16 years with food allergy and who carry an adrenaline autoinjector will be recruited from the Paediatric Allergy Clinic at Cork University Hospital, Ireland and baseline disease-specific quality of life will be ascertained using the validated Food Allergy Quality of Life Questionnaire (FAQLQ). Participants will be randomised for a period of 6 months to the 24-h telephone specialist support line or usual care. The primary outcome measure of interest is a change in FAQLQ scores, which will be assessed at 0, 1 and 6 months postrandomisation. Analysis will be on an intention-to-treat basis using a 2×3 repeated measures within-between analysis of variance. Although lacking power, we will in addition assess the impact of the intervention on a range of relevant process and clinical endpoints. ETHICS AND DISSEMINATION: This trial protocol has been approved by the Clinical Research Ethics Committee of the Cork Teaching Hospitals. The findings will be presented at international scientific conferences and will be reported on in the peer-reviewed literature in early 2013

First Long-Time Airborne Fungal Spores Study in Dublin, Ireland (1978–1980)

Ambient fungal spores within the atmosphere can contribute to a range of negative human, animal and plant health conditions and diseases. However, trends in fungal spore seasonality, species prevalence, and geographical origin have been significantly understudied in Ireland. Previously unpublished data from the late 1970s have recently been collected and analysed to establish historical fungal spore trends/characteristics for Dublin. Historical spore concentrations were largely dominated by Alternaria, Ascospores, Basidiospores, Botrytis, Cladosporium, Erysiphe and Rusts. The main fungal spore season for Dublin commenced in April with the fructification of Scopulariopsis and Ganoderma. However, the vast majority of other spore types did not reach peak spore release until late summer. The correlation between ambient spore concentration, and meteorological parameters was examined using Multivariable Regression Tree (MRT) analysis. The notable correlations found for fungal spore concentrations tended to involve temperature-based parameters. The use of a non-parametric wind regression was also employed to determine the potential geographical origin of ambient fungal spores. The impact of wind direction, and high windspeed on fungal spores was established, ultimately highlighting the importance of studying and monitoring fungal spores within Ireland, rather than attempting to rely on data from other regions, as most fungal spores collected in Dublin appeared to originate from within the island