30,045 research outputs found
Exact solution of new integrable nineteen-vertex models and quantum spin-1 chains
New exactly solvable nineteen vertex models and related quantum spin-1 chains
are solved. Partition functions, excitation energies, correlation lengths, and
critical exponents are calculated. It is argued that one of the non-critical
Hamiltonians is a realization of an integrable Haldane system. The finite-size
spectra of the critical Hamiltonians deviate in their structure from standard
predictions by conformal invariance.Comment: 16 pages, to appear in Z. Phys. B, preprint Cologne-94-474
Leisure participation amongst Hong Kong Chinese older adults
Gerontologists have recognised the important Influence of leisure activity on the mental and physical health of older adults. To date, however, there have been few studies of the patterns of participation in leisure activity among older adults in Hong Kong. This study examines a large representative sample of Hong Kong older adults and the associations between their socio-economic and health characteristics and their leisure activities. The data are from a cross-sectional survey of 2,180 respondents aged 60 or more years, conducted in 2000 by the Hong Kong Census and Statistics Department. There were full records for 2,144 respondents. Among the participation rates in the seven categories of leisure activities, watching television or listening to radio was the highest, while the lowest was for playing mahjong or cards. The characteristics that significantly correlated with the level of participation differed by the activity. Although no consistent pattern emerged, gender, education, employment status, receiving welfare benefits, self-rated health and functional impairment were the strongest correlates for most types of leisure activity. The paper is concluded by comparing the results with previous findings, and by discussing the service implications of the findings, the limitations of the study, and directions for future research. © 2004 Cambridge University Press.published_or_final_versio
Validity and normative data for thirty-second chair stand test in elderly community-dwelling Hong Kong Chinese
It is important to establish valid field measures of lower body strength in the elderly, and to provide representative normative values that are culturally specific in order to help health professionals in the risk assessment of this group. A sample of 1,038 elderly Hong Kong Chinese undertook a 30-sec chair stand test (30CST), with a subsample of 143 completing isometric measures of maximal hip flexion and knee extension, plus a habitual physical activity questionnaire. The 30CST was significantly, yet only weakly, correlated with the isometric strength measures (r ∼ 0.3-0.4), but accurately discriminated between levels of habitual physical activity and across ages in decades. The normative values generated provide useful data for health screening in this elderly Hong Kong population, but do not compare well with their healthier US counterparts. © 2006 Wiley-Liss, Inc.postprin
Patterns of physical exercise and contributing factors among Hong Kong older adults
Key Messages
1. Studies suggest that regular physical activity and exercise offer a significant opportunity to enhance
years of active independent life for older individuals. However, the majority of local respondents have a
relatively sedentary lifestyle and were not getting adequate physical activity and exercise, though many
recognised the health benefits of being active.
2. Compared with their relatively active American counterparts, in terms of strength, flexibility
and agility, the respondents of this study fared unfavourably, with mean values in the 20-30
percentile score or lower.
3. More than 80% of elderly adults regularly participated in sports activities, the majority of whom engaged in only a low-to-moderate level of physical exercise mainly due to limited choices and time allocation for such activity. Nearly 17% of the respondents engaged in walking as a leisure activity; a substantial proportion included completion of their household activities (shopping, visiting friends) in what they termed ‘walking’. As walking confers many health benefits, its promotion in the immediate environments of the elderly is practical and undoubtedly health
enhancing.
4. Findings suggested that cognitive-perceptual factors, ie perceived ‘pros’ and ‘cons’ of doing exercise, selfefficacy of exercise, stages of change and perceived barriers to exercise were all influential variables
contributing to engagement in sports activity. Longitudinal studies are needed to understand
the causal and temporal relations between these variables.
5. Health promotion programmes to educate older adults about the benefits of engaging in physical
activity with respect to their self-efficacy are crucial. Education can enhance individual’s knowledge and/or awareness concerning the health benefits of physical activity and exercise. Those who are deprived and less educated should receive more attention from
policymakers and service providers.published_or_final_versio
A simple abstraction of arrays and maps by program translation
We present an approach for the static analysis of programs handling arrays,
with a Galois connection between the semantics of the array program and
semantics of purely scalar operations. The simplest way to implement it is by
automatic, syntactic transformation of the array program into a scalar program
followed analysis of the scalar program with any static analysis technique
(abstract interpretation, acceleration, predicate abstraction,.. .). The
scalars invariants thus obtained are translated back onto the original program
as universally quantified array invariants. We illustrate our approach on a
variety of examples, leading to the " Dutch flag " algorithm
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Suppression of planar cell polarity signaling and migration in glioblastoma by Nrdp1-mediated Dvl polyubiquitination.
The lethality of the aggressive brain tumor glioblastoma multiforme (GBM) results in part from its strong propensity to invade surrounding normal brain tissue. Although oncogenic drivers such as epidermal growth factor receptor activation and Phosphatase and Tensin homolog inactivation are thought to promote the motility and invasiveness of GBM cells via phosphatidylinostitol 3-kinase activation, other unexplored mechanisms may also contribute to malignancy. Here we demonstrate that several components of the planar cell polarity (PCP) arm of non-canonical Wnt signaling including VANGL1, VANGL2 and FZD7 are transcriptionally upregulated in glioma and correlate with poorer patient outcome. Knockdown of the core PCP pathway component VANGL1 suppresses the motility of GBM cell lines, pointing to an important mechanistic role for this pathway in glioblastoma malignancy. We further observe that restoration of Nrdp1, a RING finger type E3 ubiquitin ligase whose suppression in GBM also correlates with poor prognosis, reduces GBM cell migration and invasiveness by suppressing PCP signaling. Our observations indicate that Nrdp1 physically interacts with the Vangl1 and Vangl2 proteins to mediate the K63-linked polyubiquitination of the Dishevelled, Egl-10 and Pleckstrin (DEP) domain of the Wnt pathway protein Dishevelled (Dvl). Ubiquitination hinders Dvl binding to phosphatidic acid, an interaction necessary for efficient Dvl recruitment to the plasma membrane upon Wnt stimulation of Fzd receptor and for the propagation of downstream signals. We conclude that the PCP pathway contributes significantly to the motility and hence the invasiveness of GBM cells, and that Nrdp1 acts as a negative regulator of PCP signaling by inhibiting Dvl through a novel polyubiquitination mechanism. We propose that the upregulation of core PCP components, together with the loss of the key negative regulator Nrdp1, act coordinately to promote GBM invasiveness and malignancy
Aluminium oxide in the atmosphere of hot Jupiter WASP-43bv
We have conducted a re-analysis of publicly available Hubble Space Telescope Wide Field Camera 3 (HST WFC3) transmission data for the hot-Jupiter exoplanet WASP-43b, using the Bayesian retrieval package Tau-REx. We report evidence of AlO in transmission to a high level of statistical significance (>5σ in comparison to a flat model, and 3.4σ in comparison to a model with H2O only). We find no evidence of the presence of CO, CO2, or CH4 based on the available HST WFC3 data or on Spitzer IRAC data. We demonstrate that AlO is the molecule that fits the data to the highest level of confidence out of all molecules for which high-temperature opacity data currently exists in the infrared region covered by the HST WFC3 instrument, and that the subsequent inclusion of Spitzer IRAC data points in our retrieval further supports the presence of AlO. H2O is the only other molecule we find to be statistically significant in this region. AlO is not expected from the equilibrium chemistry at the temperatures and pressures of the atmospheric layer that is being probed by the observed data. Its presence therefore implies direct evidence of some disequilibrium processes with links to atmospheric dynamics. Implications for future study using instruments such as the James Webb Space Telescope are discussed, along with future opacity needs. Comparisons are made with previous studies into WASP-43b
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