125 research outputs found
A Far-Ultraviolet Survey of 47 Tucanae.II The Long-Period Cataclysmic Variable AKO 9
We present time-resolved, far-ultraviolet (FUV) spectroscopy and photometry
of the 1.1 day eclipsing binary system AKO 9 in the globular cluster 47
Tucanae. The FUV spectrum of AKO 9 is blue and exhibits prominent C IV and He
II emission lines. The spectrum broadly resembles that of long-period,
cataclysmic variables in the galactic field.
Combining our time-resolved FUV data with archival optical photometry of 47
Tuc, we refine the orbital period of AKO 9 and define an accurate ephemeris for
the system. We also place constraints on several other system parameters, using
a variety of observational constraints. We find that all of the empirical
evidence is consistent with AKO 9 being a long-period dwarf nova in which mass
transfer is driven by the nuclear expansion of a sub-giant donor star. We
therefore conclude that AKO 9 is the first spectroscopically confirmed
cataclysmic variable in 47 Tuc.
We also briefly consider AKO 9's likely formation and ultimate evolution.
Regarding the former, we find that the system was almost certainly formed
dynamically, either via tidal capture or in a 3-body encounter. Regarding the
latter, we show that AKO 9 will probably end its CV phase by becoming a
detached, double WD system or by exploding in a Type Ia supernova.Comment: 40 pages, 11 figures, to appear in the Dec 20 issue of ApJ; minor
changes to match final published versio
Characterization of the near-Earth Asteroid 2002NY40
In August 2002, the near-Earth asteroid 2002 NY40, made its closest approach
to the Earth. This provided an opportunity to study a near-Earth asteroid with
a variety of instruments. Several of the telescopes at the Maui Space
Surveillance System were trained at the asteroid and collected adaptive optics
images, photometry and spectroscopy. Analysis of the imagery reveals the
asteroid is triangular shaped with significant self-shadowing. The photometry
reveals a 20-hour period and the spectroscopy shows that the asteroid is a
Q-type
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Facilitating primary care non-antiretroviral drug prescribing in people living with HIV: the ‘THINK ARV’ initiative
Objectives:
Older people living with HIV (PLWH) have higher rates of multimorbidity, polypharmacy and an associated increased risk of potential drug–drug interactions (DDIs). We describe the development, implementation and evaluation of an intervention to increase community prescribers’ access to specialist prescribing advice.
Methods:
Phase One: a survey evaluating General Practitioners’ (GPs’) knowledge of, and confidence detecting DDIs affecting PLWH, was circulated to eight General Practices in one UK city. Phase Two: co-production was used to develop the THINK ARV intervention for prescribers in city-wide General Practices: a dedicated mobile phone and e-mail advice service staffed by HIV specialist pharmacists. Queries were audited for 6 months pre- and post-intervention. A user-satisfaction survey was emailed to enquirers.
Results:
Phase One: 42 GPs responded, of whom 62% requested further support identifying DDIs among PLWH. Phase Two: the number of queries received increased from 25 (6 months before ‘THINK ARV’ launch) to 63 in the following 6 months (152% increase). 94% of the queries were specifically about DDIs.
Conclusions:
Increasing community prescribers’ access to specialist telephone and e-mail advice resulted in increased awareness and detection of DDIs. Similar interventions could be embedded within different healthcare settings to optimise medicines and avoid potential patient harm
Does Integrating Cognitive and Psychological Interventions Enhance Wellbeing After Acquired Brain Injury? Study Protocol for a Phase II Randomized Controlled Trial of the VaLiANT (Valued Living After Neurological Trauma) Group Program
Background and ObjectivesCognitive and emotional changes affect the majority of individuals with acquired brain injury (ABI) and are associated with poorer outcomes. The evidence for “siloed” rehabilitation approaches targeting cognition and mood separately remains mixed. Valued living (i.e., acting consistently with personal values) is associated with better psychological functioning and participation in work and other productive activities. Rehabilitation interventions that concurrently address cognitive and emotional barriers to valued living may therefore result in improved outcomes. VaLiANT (Valued Living After Neurological Trauma) is an 8-week group intervention developed by our team, which uniquely combines cognitive rehabilitation and psychological therapy to improve wellbeing and meaningful participation (i.e., valued living) following ABI.MethodThis protocol describes the design and implementation of a Phase II parallel-group randomized controlled trial with blinded outcome assessors, to evaluate the potential efficacy of VaLiANT and the feasibility of a Phase III trial. Participants are adults with a history of ABI at least 3 months prior to study entry, who experience cognitive and/or emotional difficulties and associated reduced participation in valued activities. Random allocation to the treatment condition (8-week VaLiANT group program) or a usual care waitlist control condition occurs at a 2:1 treatment: control ratio. The primary outcome is wellbeing, measured by the Warwick-Edinburgh Mental Wellbeing Scale. Secondary outcomes include measures of valued living, mood, cognitive complaints, quality of life, community participation, post-traumatic growth, and self-efficacy. All measures are collected across three time points by blinded assessors (baseline, 8-week follow-up, 16-week follow-up). Trial feasibility will be evaluated against recruitment rates, drop-out rates, intervention acceptability, and treatment fidelity (manual adherence and therapist competence).DiscussionThis trial will extend current knowledge on how to improve long-term outcomes following ABI by evaluating an innovative integrated, multi-domain approach to rehabilitation concurrently addressing cognitive and emotional barriers to participation in meaningful life roles
Rating the intelligibility of dysarthic speech amongst people with Parkinson’s Disease: a comparison of trained and untrained listeners
Intelligibility of speech is a key outcome in speech and language therapy (SLT) and research. SLT students frequently participate as raters of intelligibility but we lack information about whether they rate intelligibility in the same way as the general public. This paper aims to determine if there is a difference in the intelligibility ratings made by SLT students (trained in speech related topics) compared to individuals from the general public (untrained). The SLT students were in year 2 of a BSc programme or the first 6 months of a MSc programme. We recorded 10 speakers with Parkinson’s disease (PD) related speech reading aloud the words and sentences from the Assessment of Intelligibility of Dysarthric Speech. These speech recordings were rated for intelligibility by ‘trained’ raters and ‘untrained’ raters. The effort required to understand the speech was also reported. There were no significant differences in the measures of intelligibility from the trained and untrained raters for words or sentences after adjusting for speaker by including them as a covariate in the model. There was a slight increase in effort reported by the untrained raters for the sentences. This difference in reported effort was not evident with the words. SLT students can be recruited alongside individuals from the general public as naïve raters for evaluating intelligibility in people with speech disorders
Pregnancy-associated progression of chronic kidney disease:a study protocol for the development and validation of a clinical predictive tool (PREDICT)
Web-based self-management support for people with type 2 diabetes (HeLP-Diabetes):randomised controlled trial in English primary care
Objective: To determine the effectiveness of a web-based self-management programme for people with type 2 diabetes in improving glycaemic control and reducing diabetes-related distress. Methods Design: Individually randomised two-arm controlled trial Setting: 21 General Practices in England Participants: Adults aged 18 or over with a diagnosis of type 2 diabetes registered with participating general practices Intervention and comparator: Usual care plus either HeLP-Diabetes, an interactive, theoretically informed, web-based self-management programme or a simple, text-based website containing basic information only. Outcomes and data collection: Joint primary outcomes were glycated haemoglobin (HbA1c) and diabetes-related distress, measured by the Problem Areas in Diabetes (PAID) scale, collected at 3 and 12 months after randomisation, with 12 months the primary outcome point. Research nurses, blind to allocation collected clinical data; participants completed self-report questionnaires online. Analysis: The analysis compared groups as randomised (intention to treat) using a linear mixed effects model, adjusted for baseline data with multiple imputation of missing values. Results Of the 374 participants randomised between September 2013 and December 2014, 185 were allocated to the intervention and 189 to the control. Final (12 month) follow up data for HbA1c were available for 318 (85%) and for PAID 337 (90%) of participants. Of these, 291 (78%) and 321 (86%) responses were recorded within the pre-defined “window” of 10-14 months. Participants in the intervention group had lower HbA1c than those in the control (mean difference -0.24%; 95% Confidence Interval -0.44 to -0.049; p=0.014). There was no significant overall difference between groups in the mean PAID score (p=0.21), but pre-specified subgroup analysis of participants who had had diabetes for less than 7 years showed a beneficial impact of the intervention in this group (p = 0.004). There were no reported harms. Conclusions Access to HeLP-Diabetes improved glycaemic control over 12 months
Modern optical astronomy: technology and impact of interferometry
The present `state of the art' and the path to future progress in high
spatial resolution imaging interferometry is reviewed. The review begins with a
treatment of the fundamentals of stellar optical interferometry, the origin,
properties, optical effects of turbulence in the Earth's atmosphere, the
passive methods that are applied on a single telescope to overcome atmospheric
image degradation such as speckle interferometry, and various other techniques.
These topics include differential speckle interferometry, speckle spectroscopy
and polarimetry, phase diversity, wavefront shearing interferometry,
phase-closure methods, dark speckle imaging, as well as the limitations imposed
by the detectors on the performance of speckle imaging. A brief account is
given of the technological innovation of adaptive-optics (AO) to compensate
such atmospheric effects on the image in real time. A major advancement
involves the transition from single-aperture to the dilute-aperture
interferometry using multiple telescopes. Therefore, the review deals with
recent developments involving ground-based, and space-based optical arrays.
Emphasis is placed on the problems specific to delay-lines, beam recombination,
polarization, dispersion, fringe-tracking, bootstrapping, coherencing and
cophasing, and recovery of the visibility functions. The role of AO in
enhancing visibilities is also discussed. The applications of interferometry,
such as imaging, astrometry, and nulling are described. The mathematical
intricacies of the various `post-detection' image-processing techniques are
examined critically. The review concludes with a discussion of the
astrophysical importance and the perspectives of interferometry.Comment: 65 pages LaTeX file including 23 figures. Reviews of Modern Physics,
2002, to appear in April issu
Planck 2013 results. XXII. Constraints on inflation
We analyse the implications of the Planck data for cosmic inflation. The Planck nominal mission temperature anisotropy measurements, combined with the WMAP large-angle polarization, constrain the scalar spectral index to be ns = 0:9603 _ 0:0073, ruling out exact scale invariance at over 5_: Planck establishes an upper bound on the tensor-to-scalar ratio of r < 0:11 (95% CL). The Planck data thus shrink the space of allowed standard inflationary models, preferring potentials with V00 < 0. Exponential potential models, the simplest hybrid inflationary models, and monomial potential models of degree n _ 2 do not provide a good fit to the data. Planck does not find statistically significant running of the scalar spectral index, obtaining dns=dln k = 0:0134 _ 0:0090. We verify these conclusions through a numerical analysis, which makes no slowroll approximation, and carry out a Bayesian parameter estimation and model-selection analysis for a number of inflationary models including monomial, natural, and hilltop potentials. For each model, we present the Planck constraints on the parameters of the potential and explore several possibilities for the post-inflationary entropy generation epoch, thus obtaining nontrivial data-driven constraints. We also present a direct reconstruction of the observable range of the inflaton potential. Unless a quartic term is allowed in the potential, we find results consistent with second-order slow-roll predictions. We also investigate whether the primordial power spectrum contains any features. We find that models with a parameterized oscillatory feature improve the fit by __2 e_ _ 10; however, Bayesian evidence does not prefer these models. We constrain several single-field inflation models with generalized Lagrangians by combining power spectrum data with Planck bounds on fNL. Planck constrains with unprecedented accuracy the amplitude and possible correlation (with the adiabatic mode) of non-decaying isocurvature fluctuations. The fractional primordial contributions of cold dark matter (CDM) isocurvature modes of the types expected in the curvaton and axion scenarios have upper bounds of 0.25% and 3.9% (95% CL), respectively. In models with arbitrarily correlated CDM or neutrino isocurvature modes, an anticorrelated isocurvature component can improve the _2 e_ by approximately 4 as a result of slightly lowering the theoretical prediction for the ` <_ 40 multipoles relative to the higher multipoles. Nonetheless, the data are consistent with adiabatic initial conditions
Primordial power spectrum from WMAP
The observed angular power spectrum of the cosmic microwave background
temperature anisotropy, , is a convolution of a cosmological radiative
transport kernel with an assumed primordial power spectrum of inhomogeneities.
Exquisite measurements of over a wide range of multipoles from the
Wilkinson Microwave Anisotropy Probe (WMAP) has opened up the possibility to
deconvolve the primordial power spectrum for a given set of cosmological
parameters (base model). We implement an improved (error sensitive)
Richardson-Lucy deconvolution algorithm on the measured angular power spectrum
from WMAP assuming a concordance cosmological model. The most prominent feature
of the recovered is a sharp, infra-red cut off on the horizon scale. The
resultant spectrum using the recovered spectrum has a likelihood far
better than a scale invariant, or, `best fit' scale free spectra
( {\it w.r.t.} Harrison Zeldovich, and, {\it w.r.t.} power law with ). The recovered has a
localized excess just below the cut-off which leads to great improvement of
likelihood over the simple monotonic forms of model infra-red cut-off spectra
considered in the post WMAP literature. The recovered , in particular,
the form of infra-red cut-off is robust to small changes in the cosmological
parameters. We show that remarkably similar form of infra-red cutoff is known
to arise in very reasonable extensions and refinements of the predictions from
simple inflationary scenarios. Our method can be extended to other cosmological
observations such as the measured matter power spectrum and, in particular, the
much awaited polarization spectrum from WMAP.Comment: 20 pages, 12 figures, uses Revtex4, Matches version accepted to Phys.
Rev. D. More extensive discussion of the method in the appendix, references
added and typos correcte
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