143 research outputs found
Mean link versus average plaquette tadpoles in lattice NRQCD
We compare mean-link and average plaquette tadpole renormalization schemes in
the context of the quarkonium hyperfine splittings in lattice NRQCD.
Simulations are done for the three quarkonium systems , , and
. The hyperfine splittings are computed both at leading and at
next-to-leading order in the relativistic expansion. Results are obtained at a
large number of lattice spacings. A number of features emerge, all of which
favor tadpole renormalization using mean links. This includes much better
scaling of the hyperfine splittings in the three quarkonium systems. We also
find that relativistic corrections to the spin splittings are smaller with
mean-link tadpoles, particularly for the and systems. We
also see signs of a breakdown in the NRQCD expansion when the bare quark mass
falls below about one in lattice units (with the bare quark masses turning out
to be much larger with mean-link tadpoles).Comment: LATTICE(heavyqk) 3 pages, 2 figure
Systematic overview of economic evaluations of health-related rehabilitation
Background: Health related rehabilitation is instrumental in improving functioning and promoting participation by people with disabilities. To make clinical and policy decisions about health-related rehabilitation, resource allocation and cost issues need to be considered. Objectives: To conduct an overview of systematic reviews (SRs) on economic evaluations of health-related rehabilitation. Methods: We searched multiple databases to identify relevant SRs of economic evaluations of health-related rehabilitation. Review quality was assessed by AMSTAR checklist. Results: We included 64 SRs, most of which included economic evaluations alongside randomised controlled trials (RCTs). The review quality was low to moderate (AMSTAR score 5-8) in 35, and high (score 9-11) in 29 of the included SRs. The included SRs addressed various health conditions, including spinal or other pain conditions (n=14), age-related problems (11), stroke (7), musculoskeletal disorders (6), heart diseases (4), pulmonary (3), mental health problems (3), and injury (3). Physiotherapy was the most commonly evaluated rehabilitation intervention in the included SRs (n=24). Other commonly evaluated interventions included multidisciplinary programmes (14); behavioural, educational or psychological interventions (11); home-based interventions (11); complementary therapy (6); self-management (6); and occupational therapy (4). Conclusions: Although the available evidence is often described as limited, inconsistent or inconclusive, some rehabilitation interventions were cost-effective or showed cost-saving in a variety of disability conditions. Available evidence comes predominantly from high income countries, therefore economic evaluations of health-related rehabilitation are urgently required in less resourced settings
Tadpole-improved SU(2) lattice gauge theory
A comprehensive analysis of tadpole-improved SU(2) lattice gauge theory is
made. Simulations are done on isotropic and anisotropic lattices, with and
without improvement. Two tadpole renormalization schemes are employed, one
using average plaquettes, the other using mean links in Landau gauge.
Simulations are done with spatial lattice spacings in the range of about
0.1--0.4 fm. Results are presented for the static quark potential, the
renormalized lattice anisotropy (where is the ``temporal''
lattice spacing), and for the scalar and tensor glueball masses. Tadpole
improvement significantly reduces discretization errors in the static quark
potential and in the scalar glueball mass, and results in very little
renormalization of the bare anisotropy that is input to the action. We also
find that tadpole improvement using mean links in Landau gauge results in
smaller discretization errors in the scalar glueball mass (as well as in the
static quark potential), compared to when average plaquettes are used. The
possibility is also raised that further improvement in the scalar glueball mass
may result when the coefficients of the operators which correct for
discretization errors in the action are computed beyond tree level.Comment: 14 pages, 7 figures (minor changes to overall scales in Fig.1; typos
removed from Eqs. (3),(4),(15); some rewording of Introduction
Tadpole renormalization and relativistic corrections in lattice NRQCD
We make a comparison of two tadpole renormalization schemes in the context of
the quarkonium hyperfine splittings in lattice NRQCD. Improved gauge-field and
NRQCD actions are analyzed using the mean-link in Landau gauge, and
using the fourth root of the average plaquette . Simulations are done
for , , and systems. The hyperfine splittings are
computed both at leading and at next-to-leading order in the relativistic
expansion. Results are obtained at lattice spacings in the range of about
0.14~fm to 0.38~fm. A number of features emerge, all of which favor tadpole
renormalization using . This includes much better scaling behavior of
the hyperfine splittings in the three quarkonium systems when is
used. We also find that relativistic corrections to the spin splittings are
smaller when is used, particularly for the and
systems. We also see signs of a breakdown in the NRQCD expansion when the bare
quark mass falls below about one in lattice units. Simulations with
also appear to be better behaved in this context: the bare quark masses turn
out to be larger when is used, compared to when is used on
lattices with comparable spacings. These results also demonstrate the need to
go beyond tree-level tadpole improvement for precision simulations.Comment: 14 pages, 7 figures (minor changes to some phraseology and
references
Adjoint "quarks" on coarse anisotropic lattices: Implications for string breaking in full QCD
A detailed study is made of four dimensional SU(2) gauge theory with static
adjoint ``quarks'' in the context of string breaking. A tadpole-improved action
is used to do simulations on lattices with coarse spatial spacings ,
allowing the static potential to be probed at large separations at a
dramatically reduced computational cost. Highly anisotropic lattices are used,
with fine temporal spacings , in order to assess the behavior of the
time-dependent effective potentials. The lattice spacings are determined from
the potentials for quarks in the fundamental representation. Simulations of the
Wilson loop in the adjoint representation are done, and the energies of
magnetic and electric ``gluelumps'' (adjoint quark-gluon bound states) are
calculated, which set the energy scale for string breaking. Correlators of
gauge-fixed static quark propagators, without a connecting string of spatial
links, are analyzed. Correlation functions of gluelump pairs are also
considered; similar correlators have recently been proposed for observing
string breaking in full QCD and other models. A thorough discussion of the
relevance of Wilson loops over other operators for studies of string breaking
is presented, using the simulation results presented here to support a number
of new arguments.Comment: 22 pages, 14 figure
“It’s a silver lining”: A template analysis of satisfaction and quality of life following post-mastectomy breast reconstruction
The file attached to this record is the author's final peer reviewed version.Objective: In the United Kingdom, the number of women electing to undergo post-mastectomy breast reconstruction is increasing. As a consequence exploring patient-reported outcomes in breast surgery has become increasingly important. This study aims to explore satisfaction and quality of life following post-mastectomy breast reconstruction.
Design: Qualitative research design.
Methods: In-depth, semi-structured telephone interviews were conducted with 25 women, (Age, M= 53.08, SD=8.41) following breast reconstruction in the United Kingdom. Data were analysed using template analysis which produced three first-level, 13 second-level and 19 third-level themes.
Results: Following reconstruction women reported improved emotional functioning, although this was often accompanied with deterioration in physical, sexual and/or social functioning. Women positively appraised their breast appearance, although some reported a decline in satisfaction over time and attributed this decline to their chosen reconstructive technique. Many women accepted the inevitability of scarring and most perceived their scars as a representation of their journey, signifying survival. Generally women were satisfied with the outcome of their reconstruction, although on reflection some would not have opted for reconstruction. Following breast reconstruction women were increasingly likely to experience the fear of recurrence, attributed to no longer being able to have a mammogram on the affected breast(s).
Conclusions: This study provides new insights into post-mastectomy breast reconstruction and is a novel application of the qualitative data analysis method, template analysis. Template analysis demonstrates only slight variation in some categories of experience among women, despite a heterogeneous sample. The findings allow researchers and clinicians to focus on specific dimensions of satisfaction and quality of life to positively support the needs of women following reconstructio
Choice in the context of informal care-giving
Extending choice and control for social care service users is a central feature of current English policies. However, these have comparatively little to say about choice in relation to the informal carers of relatives, friends or older people who are disabled or sick. To explore the realities of choice as experienced by carers, the present paper reviews research published in English since 1985 about three situations in which carers are likely to face choices: receiving social services; the entry of an older person to long-term care; and combining paid work and care. Thirteen electronic databases were searched, covering both the health and social care fields. Databases included: ASSIA; IBSS; Social Care Online; ISI Web of Knowledge; Medline; HMIC Sociological Abstracts; INGENTA; ZETOC; and the National Research Register. The search strategy combined terms that: (1) identified individuals with care-giving responsibilities; (2) identified people receiving help and support; and (3) described the process of interest (e.g. choice, decision-making and self-determination). The search identified comparatively few relevant studies, and so was supplemented by the findings from another recent review of empirical research on carers' choices about combining work and care. The research evidence suggests that carers' choices are shaped by two sets of factors: one relates to the nature of the care-giving relationship; and the second consists of wider organisational factors. A number of reasons may explain the invisibility of choice for carers in current policy proposals for increasing choice. In particular, it is suggested that underpinning conceptual models of the relationship between carers and formal service providers shape the extent to which carers can be offered choice and control on similar terms to service users. In particular, the exercise of choice by carers is likely to be highly problematic if it involves relinquishing some unpaid care-giving activities
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Assessment of perinatal anxiety: diagnostic accuracy of five measures
Background
Anxiety in pregnancy and after giving birth (the perinatal period) is highly prevalent but under-recognised. Robust methods of assessing perinatal anxiety are essential for services to identify and treat women appropriately.
Aims
To determine which assessment measures are most psychometrically robust and effective at identifying women with perinatal anxiety (primary objective) and depression (secondary objective).
Method
We conducted a prospective longitudinal cohort study of 2243 women who completed five measures of anxiety and depression (Generalized Anxiety Disorder scale (GAD) two- and seven-item versions; Whooley questions; Clinical Outcomes in Routine Evaluation (CORE-10); and Stirling Antenatal Anxiety Scale (SAAS)) during pregnancy (15 weeks, 22 weeks and 31 weeks) and after birth (6 weeks). To assess diagnostic accuracy a sample of 403 participants completed modules of the Mini-International Neuropsychiatric Interview (MINI).
Results
The best diagnostic accuracy for anxiety was shown by the CORE-10 and SAAS. The best diagnostic accuracy for depression was shown by the CORE-10, SAAS and Whooley questions, although the SAAS had lower specificity. The same cut-off scores for each measure were optimal for identifying anxiety or depression (SAAS ≥9; CORE-10 ≥9; Whooley ≥1). All measures were psychometrically robust, with good internal consistency, convergent validity and unidimensional factor structure.
Conclusions
This study identified robust and effective methods of assessing perinatal anxiety and depression. We recommend using the CORE-10 or SAAS to assess perinatal anxiety and the CORE-10 or Whooley questions to assess depression. The GAD-2 and GAD-7 did not perform as well as other measures and optimal cut-offs were lower than currently recommended
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