1,495 research outputs found
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
.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
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
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