2,991 research outputs found
An architecture for efficient gravitational wave parameter estimation with multimodal linear surrogate models
The recent direct observation of gravitational waves has further emphasized
the desire for fast, low-cost, and accurate methods to infer the parameters of
gravitational wave sources. Due to expense in waveform generation and data
handling, the cost of evaluating the likelihood function limits the
computational performance of these calculations. Building on recently developed
surrogate models and a novel parameter estimation pipeline, we show how to
quickly generate the likelihood function as an analytic, closed-form
expression. Using a straightforward variant of a production-scale parameter
estimation code, we demonstrate our method using surrogate models of
effective-one-body and numerical relativity waveforms. Our study is the first
time these models have been used for parameter estimation and one of the first
ever parameter estimation calculations with multi-modal numerical relativity
waveforms, which include all l <= 4 modes. Our grid-free method enables rapid
parameter estimation for any waveform with a suitable reduced-order model. The
methods described in this paper may also find use in other data analysis
studies, such as vetting coincident events or the computation of the
coalescing-compact-binary detection statistic.Comment: 10 pages, 3 figures, and 1 tabl
Effect of Canal Bank Engineering Disturbance on Plant Communities: Analysis of Taxonomic and Functional Beta Diversity
We aimed to determine how patterns of functional and taxonomic dissimilarities and their components differ between disturbed and undisturbed plant communities. Taxonomic (species) and functional (trait) diversity are key aspects of biodiversity, and their respective dissimilarities are important in diversity scaling and for informing conservation. We utilized a pseudo-experimental setting, the Basingstoke Canal, UK, where sections of canal bank have been repaired over a four-year period and are interspersed with sections left undisturbed. We collected plant community data, computed functional beta diversity and taxonomic beta diversity and partitioned them into species loss and replacement components. We compared disturbed and undisturbed plots with respect to these dissimilarity measures, the time since disturbance, invasive species, plant life-forms and environmental dissimilarity. We found high levels of taxonomic (85–90%) and functional (70–76%) dissimilarities between disturbed and undisturbed sites, primarily driven by turnover. The total dissimilarity was lower for functional dissimilarity than taxonomic dissimilarity. Disturbed sites had greater between-site taxonomic and functional dissimilarities and lower plant abundances than undisturbed sites, driven by both turnover and nestedness components. The disturbed site functional diversity diverged strongly from null expectations. We found no significant effects of time since disturbance, environmental variables or invasive species, possibly indicating the dominance of stochastic, local-scale processes. However, disturbed sites had lower levels of phanerophyte richness and higher levels of therophyte richness. Our results indicate that small-scale disturbances may increase taxonomic and functional between-community dissimilarities in anthropogenic habitats without increasing invasive species, lending support to local-scale conservation that enhances habitat heterogeneity to promote taxonomic diversity and its corresponding biotic functions
Hyperalkaline speleothem from Derbyshire: new observations on morphology and growth crystallisation
Cardiac rehabilitation services for people in rural and remote areas: an integrative literature review
Introduction: Morbidity and mortality from heart disease continues to be high in Australia with cardiac rehabilitation (CR) recognised as best practice for people with heart disease. CR is known to reduce mortality, reoccurrence of heart disease, hospital readmissions and costs, and to improve quality of life. Australian Aboriginal and Torres Strait Islanders (Australian First Peoples or Indigenous peoples) have a greater need for CR due to their higher burden of disease. However, CR referral, access and attendance remain low for all people who live in rural and remote areas. The aim of this integrative review was to identify barriers, enablers and pathways to CR for adults living independently in rural and remote areas of high-income countries, including Australia.
Methods: Studies were identified through five online data bases, plus reference lists of the selected studies. The studies focused on barriers and enablers of CR for adults in rural and remote areas of Australia and other high-income countries, in English peer reviewed journals (2007-2016). A mix of qualitative, quantitative and mixed method studies were reviewed through a modified Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA), followed by a critical review and thematic analysis.
Results: Sixteen studies were selected: seven qualitative, four quantitative and five mixed method. Five themes that influence CR attendance were identified: referral, health services pathways and planning; cultural and geographic factors necessitating alternative and flexible programs; professional roles and influence; knowing, valuing, and psychosocial factors; and financial costs - personal and health services. Factors identified that impact on referral and access to CR were hospital inpatient education programs on heart disease and risk factors; discharge processes including CR eligibility criteria and referral to ensure continuum and transition of care; need for improved accessibility of services, both geographically and through alternative programs, including home based with IT and/or telephone support Also, the need to ensure that health professionals understand, value and support CR; the impact of mental health, coping with change and competing priorities; costs including travel, medications and health professional consultations; as well as low levels of involvement of Australian First Peoples in their own care and poor cultural understanding by non-Australian First Peoples staff all negatively impact on CR access and attendance.
Conclusion: This study found weak systems with low referral rates and poor access to CR in rural and remote areas. Underlying factors include lack of health professional and public support, often based on poor perception of benefits of CR, compounded by scarce and inflexible services. Low levels of involvement of Australian First Peoples, as well as a lack of cultural understanding by non-Australian First Peoples staff, is evident Overall, the findings demonstrate the need for improved models of referral and access, greater flexibility of programs and professional roles, with management support Further, increased education and involvement of Australian First Peoples, including Indigenous health workers taking a lead in their own people's care, supported by improved education and greater cultural awareness of non Australian First Peoples staff, is required
Improving access to cardiac rehabilitation in rural and remote areas: a protocol for a community-based qualitative case study
Background/Aims
Heart disease is the largest single cause of death and contributes to poor quality of life and high healthcare costs in Australia. There are higher rates of heart disease in rural and remote areas, with the highest rates in Aboriginal and Torres Strait Islander people. Cardiac rehabilitation is known to improve health outcomes for people with heart disease but referral rates remain low (30.2% overall and 46% following acute coronary syndrome) in Australia. Further, access to cardiac rehabilitation in rural and remote areas is affected by there being few centre-based services, and poor use of home-based services. The aim of this protocol is to investigate: (i) understanding of cardiac rehabilitation by health staff, community leaders and community participants discharged from hospital following treatment for heart disease; (ii) access and support for cardiac rehabilitation in rural and remote areas via health service availability in each community.
Methods
A qualitative case study methodology, using an interpretive descriptive framework, will be used together with content analysis that will encompass identification of themes through a deductive/inductive process.
Conclusions
To improve access to services and health outcomes in rural and remote areas, a strong evidence base is essential. To achieve this, as well as having appropriate methodology, it is necessary to build relationships and trust with local communities and healthcare providers. This research protocol describes a qualitative community-based case study, together with processes to build sound relationships required for effective data collection through semi-structured interviews or focus groups. Each step of the pre-research planning data collection and analysis is described in detail for the guidance of future researchers
Functionalized micro-capillary film for the rapid at-line analysis of IgG aggregates in a cell culture bioreactor.
A micro-capillary film has been developed that offers the potential for an at-line analytical tool for rapid aggregate analysis during biopharmaceutical antibody production. A non-porous walled micro-capillary film (NMCF) with cation exchange functionality was demonstrated to act as a chromatography medium that could be operated with high linear fluid velocities and was highly resistant to blockage by entrained particulates, including cells. The NMCF containing 19 parallel microcapillaries was prepared using a melt extrusion process from poly(ethylene-vinyl alcohol) copolymer (EVOH). The NMCF-EVOH was modified to have cation-exchange functionality (NMCF-EVOH-SP) and shown to differentially bind monomer and aggregated species of IgG antibody directly from a bioreactor. The use of NMCF-EVOH-SP to quantify aggregate concentrations in monoclonal antibody preparations in less than 20 minutes was demonstrated.The authors would like to thank the EPSRC for the provision of a CASE Award. This study was sponsored by MedImmune, the global biologics R&D arm of AstraZeneca.This is the final version of the article. It first appeared from Taylor & Francis via http://dx.doi.org/10.1080/19420862.2015.106536
Impact of subdominant modes on the interpretation of gravitational-wave signals from heavy binary black hole systems
Over the past year, a handful of new gravitational wave models have been developed to include multiple harmonic modes thereby enabling for the first time fully Bayesian inference studies including higher modes to be performed. Using one recently developed numerical relativity surrogate model, NRHybSur3dq8, we investigate the importance of higher modes on parameter inference of coalescing massive binary black holes. We focus on examples relevant to the current three-detector network of observatories, with a detector-frame mass set to
120 M⊙ and with signal amplitude values that are consistent with plausible candidates for the next few observing runs. We show that for such systems the higher mode content will be important for interpreting coalescing binary black holes, reducing systematic bias, and computing properties of the remnant object. Even for comparable-mass binaries and at low signal amplitude, the omission of higher modes can influence posterior probability distributions. We discuss the impact of our results on source population inference and self-consistency tests of general relativity. Our work can be used to better understand asymmetric binary black hole merger events, such as GW190412. Higher modes are critical for such systems, and their omission usually produces substantial parameter biases
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