6,699 research outputs found
Cardiovascular medication, physical activity and mortality: cross-sectional population study with ongoing mortality follow up
Objective: to establish physical activity levels in relation to cardiovascular medication and to examine if physical activity is associated with benefit independently of medication among individuals with no diagnosis of cardiovascular disease (CVD).
Design: Cross-sectional surveys in 1998 and 2003 with ongoing mortality follow up.
Setting: Household-based interviews in England and Scotland.
Participants: Population samples of adults aged 35 and over living in households, respondents of the Scottish Health Survey and the Health Survey for England.
Main outcome measure: Moderate to vigorous physical activity (MVPA) levels and CVD mortality.
Results: Fifteen percent (N=3,116) of the 20,177 respondents (8,791 men); were prescribed at least one cardiovascular medication. Medicated respondents were less likely than those unmedicated to meet the physical activity recommendations (OR:0.89, 95%CI: 0.81 to 0.99, p=0.028). The mean follow up (±SD) was 6.6 (2.3) years. There were 1,509 any-cause deaths and 427 CVD deaths. Increased physical activity was associated with all-cause and CVD mortality among both unmedicated (all-cause mortality HR for those with ≥150 min/wk of MVPA compared with those who reported no MVPA): 0.58, 95%CI: 0.48 to 0.69, p<0.001) ; CVD mortality: 0.65, 0.46 to 0.91, p=0.036) and medicated respondents (all-cause death: 0.54, 0.40 to 0.72, p<0.001; CVD death: 0.46 (0.27 to 0.78, p=0.008).
Conclusions: Although physical activity protects against premature mortality among both medicated and unmedicated adults, cardiovascular medication is linked with lower uptake of health enhancing physical activity. These results highlight the importance of physical activity in the primary prevention of CVD over and above medication
Quantum phase transitions in the J-J' Heisenberg and XY spin-1/2 antiferromagnets on square lattice: Finite-size scaling analysis
We investigate the critical parameters of an order-disorder quantum phase
transitions in the spin-1/2 Heisenberg and XY antiferromagnets on square
lattice. Basing on the excitation gaps calculated by exact diagonalization
technique for systems up to 32 spins and finite-size scaling analysis we
estimate the critical couplings and exponents of the correlation length for
both models. Our analysis confirms the universal critical behavior of these
quantum phase transitions: They belong to 3D O(3) and 3D O(2) universality
classes, respectively.Comment: 7 pages, 3 figure
A new substrate for sampling deep river macroinvertebrates
We compared macroinvertebrate communities colonising multiplate samplers constructed from perspex or tempered hardboard (wood) with an alternative artificial substrate constructed from folded coconut fibre matting (coir) enclosed in nylon netting. Substrates were incubated for 62 days over January to March 2007 at six sites over 240 km along the Waikato River. The three substrates supported similar numbers of invertebrate taxa (27 - 29 taxa), but coir samples contained 71% of total invertebrate numbers from all substrates combined, compared with <17% for each type of multiplate sampler. Coir faunas were heavily dominated by the hydrobiid snail Potamopyrgus (84 % of numbers), and this taxon along with the amphipod Paracalliope comprised 58 - 66 % of invertebrates on both types of multiplate samplers. Analysis of a Bray-Curtis matrix suggested statistically significant differences in percent community composition between coir samplers and each type of multiplate sampler over the late summer study period. Densities per cm3 of Oligochaeta, Mollusca, and "other worms" (Platyhelminthes, Rhabdocoela, Nemertea and Hirudinea combined) were significantly higher in coir samples than one or both of the multiplate samplers. Results suggest coir samplers may provide a useful supplement to multiplate samplers for deep river invertebrate studies by collecting a different range of taxa, including those favouring cover and characteristic of depositional environments
Series Expansions for Excited States of Quantum Lattice Models
We show that by means of connected-graph expansions one can effectively
generate exact high-order series expansions which are informative of low-lying
excited states for quantum many-body systems defined on a lattice. In
particular, the Fourier series coefficients of elementary excitation spectra
are directly obtained. The numerical calculations involved are straightforward
extensions of those which have already been used to calculate series expansions
for ground-state correlations and susceptibilities in a wide variety of
models. As a test, we have reproduced the known elementary excitation spectrum
of the transverse-field Ising chain in its disordered phase.Comment: 9 pages, no figures, Revtex 3.0 The revised version corrects the
incorrect (and unnecessary) statement in the original that H and H^eff are
related by a unitary transformation; in fact they are related by via a
similarity transformation. This has no implications for the calculations of
spectra, but is important for matrix element
Spin-wave excitation spectra and spectral weights in square lattice antiferromagnets
Using a recently developed method for calculating series expansions of the
excitation spectra of quantum lattice models, we obtain the spin-wave spectra
for square lattice, Heisenberg-Ising antiferromagnets. The calculated
spin-wave spectrum for the Heisenberg model is close to but noticeably
different from a uniformly renormalized classical (large-) spectrum with the
renormalization for the spin-wave velocity of approximately . The
relative weights of the single-magnon and multi-magnon contributions to neutron
scattering spectra are obtained for wavevectors throughout the Brillouin zone.Comment: Two postscript figures, 4 two-column page
Cold gas in group-dominant elliptical galaxies
We present IRAM 30m telescope observations of the CO(1-0) and (2-1) lines in
a sample of 11 group-dominant elliptical galaxies selected from the CLoGS
nearby groups sample. Our observations confirm the presence of molecular gas in
4 of the 11 galaxies at >4 sigma significance, and combining these with data
from the literature we find a detection rate of 43+-14%, comparable to the
detection rate for nearby radio galaxies, suggesting that group-dominant
ellipticals may be more likely to contain molecular gas than their non-central
counterparts. Those group-dominant galaxies which are detected typically
contain ~2x10^8 Msol of molecular gas, and although most have low star
formation rates (<1 Msol/yr) they have short depletion times, indicating that
the gas must be replenished on timescales ~100 Myr. Almost all of the galaxies
contain active nuclei, and we note while the data suggest that CO may be more
common in the most radio-loud galaxies, the mass of molecular gas required to
power the active nuclei through accretion is small compared to the masses
observed. We consider possible origin mechanisms for the gas, through cooling
of stellar ejecta within the galaxies, group-scale cooling flows, and gas-rich
mergers, and find probable examples of each type within our sample, confirming
that a variety of processes act to drive the build up of molecular gas in
group-dominant ellipticals.Comment: 9 pages, 5 postscript figures, 4 tables, accepted by A&A. Revised
throughout in response to referee's comments, including updates to Table 1
and Figure 4, and addition of Figure
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‘Nerds’, ‘Space-Cadets’ and those ‘a bit on the odd side’: an interpretative phenomenological analysis of the experience of adolescents with a diagnosis of Developmental Coordination Disorder (DCD)
Introduction: Adolescents with Developmental Coordination Disorder (DCD) are known to be at increased risk of psychosocial problems. There has been limited qualitative research into the impact of DCD from an adolescent perspective.
Aim: The purpose of this study was to gain a deeper understanding of the lived experience of participants with DCD as they negotiate adolescence.
Method: Eleven participants between the age of 11-18 (8F:3M) with a diagnosis of DCD were recruited through the Dyspraxia Foundation UK. Semi-structured interviews were carried out, audio-recorded and transcribed. The data was analysed by means of Interpretative Phenomenological Analysis (IPA).
Findings: Three main themes emerged from the data: ‘Sense of Otherness’ ‘Complexity of Response’ ‘Recognising and Coping with Limitations’. Most participants related a sense of ‘otherness’ and had previously experienced social and/or emotional difficulties. However, adolescence emerged as a time where self-concept could be re-assessed, often positively. Feelings regarding DCD were expressed as complex - including relief at diagnosis, shame at limitations, general ambivalence and a need for acceptance and support. Participants felt their difficulties were often unrecognised and misunderstood in comparison to other developmental disorders. Limitations were described regarding coordination, executive functions (EF) and emotional response. Participants employed a diverse range of coping strategies to function academically and socially.
Conclusion: This work has implications for professionals and policymakers regarding the continued lack of recognition and understanding perceived by young people with DCD. It highlights that many participants struggle with EF and emotional regulation, as well as coordination, but feel that this struggle is mostly unseen. Support, when offered, can often be inconsistent. The re-framing of ‘difference’ as ‘individuality’ during mid to late adolescence, indicates an alternative pathway regarding self-concept that is potentially inclusive of DCD. As adults with DCD continue to report lower self-esteem, poorer mental health outcomes and reduced participation, this research indicates that adolescence may present a window of opportunity for interventions to improve resilience and self-esteem in this population. Ongoing active collaboration between adolescents and researchers is essential
Critical and off-critical studies of the Baxter-Wu model with general toroidal boundary conditions
The operator content of the Baxter-Wu model with general toroidal boundary
conditions is calculated analytically and numerically. These calculations were
done by relating the partition function of the model with the generating
function of a site-colouring problem in a hexagonal lattice. Extending the
original Bethe-ansatz solution of the related colouring problem we are able to
calculate the eigenspectra of both models by solving the associated
Bethe-ansatz equations. We have also calculated, by exploring the conformal
invariance at the critical point, the mass ratios of the underlying massive
theory governing the Baxter-Wu model in the vicinity of its critical point.Comment: 32 pages latex, to appear in J. Phys. A: Math. Ge
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