54 research outputs found
Examining physical activity and quality of life in adults with autism spectrum disorder and intellectual disability
Adults with autism and co-occurring intellectual disability engage in low levels of physical activity and are at increased risk of developing secondary health conditions attributed to physical inactivity compared to adults in the general population. Few studies have examined the use of objective measures to characterize physical activity levels for adults with autism and intellectual disability. The current study aimed to examine the relationship between physical activity, using an activity tracker, and quality of life in adults with autism and intellectual disability. In the current study, 38 adults with autism and intellectual disability, ages 18–55, wore a Fitbit Flex 2® activity tracker for 1 week, and completed the Quality of Life Questionnaire. The relationship between average daily step count quality of life was examined. Most adults in the sample were overweight and taking fewer daily steps than recommended guidelines. Increased average daily step count was significantly associated with quality of life
Baryon Decuplet to Octet Electromagnetic Transitions in Quenched and Partially Quenched Chiral Perturbation Theory
We calculate baryon decuplet to octet electromagnetic transition form factors
in quenched and partially quenched chiral perturbation theory. We work in the
isospin limit of SU(3) flavor, up to next-to-leading order in the chiral
expansion, and to leading order in the heavy baryon expansion. Our results are
necessary for proper extrapolation of lattice calculations of these
transitions. We also derive expressions for the case of SU(2) flavor away from
the isospin limit.Comment: 16 pages, 3 figures, revtex
Electromagnetic Decays of Heavy Baryons
The electromagnetic decays of the ground state baryon multiplets with one
heavy quark are calculated using Heavy Hadron Chiral Perturbation Theory. The
M1 and E2 amplitudes for S^{*}--> S gamma, S^{*} --> T gamma and S --> T gamma
are separately computed. All M1 transitions are calculated up to
O(1/Lambda_chi^2). The E2 amplitudes contribute at the same order for S^{*}-->
S gamma, while for S^{*} --> T gamma they first appear at O(1/(m_Q
\Lambda_\chi^2)) and for S --> T gamma are completely negligible. The
renormalization of the chiral loops is discussed and relations among different
decay amplitudes are derived. We find that chiral loops involving
electromagnetic interactions of the light pseudoscalar mesons provide a sizable
enhancement of these decay widths. Furthermore, we obtain an absolute
prediction for the widths of Xi^{0'(*)}_c--> Xi^{0}_c gamma and Xi^{-'(*)}_b-->
Xi^{-}_b gamma. Our results are compared to other estimates existing in the
literature.Comment: 17 pages, 3 figures, submitted to Phys. Rev.
Neutrino-Deuteron Scattering in Effective Field Theory at Next-to-Next-to Leading Order
We study the four channels associated with neutrino-deuteron breakup
reactions at next-to-next to leading order in effective field theory. We find
that the total cross-section is indeed converging for neutrino energies up to
20 MeV, and thus our calculations can provide constraints on theoretical
uncertainties for the Sudbury Neutrino Observatory. We stress the importance of
a direct experimental measurement to high precision in at least one channel, in
order to fix an axial two-body counterterm.Comment: 32 pages, 14 figures (eps
Chiral Analysis of Quenched Baryon Masses
We extend to quenched QCD an earlier investigation of the chiral structure of
the masses of the nucleon and the delta in lattice simulations of full QCD.
Even after including the meson-loop self-energies which give rise to the
leading and next-to-leading non-analytic behaviour (and hence the most rapid
variation in the region of light quark mass), we find surprisingly little
curvature in the quenched case. Replacing these meson-loop self-energies by the
corresponding terms in full QCD yields a remarkable level of agreement with the
results of the full QCD simulations. This comparison leads to a very good
understanding of the origins of the mass splitting between these baryons.Comment: 23 pages, 6 figure
Concurrent tolerance allocation and scheduling for complex assemblies
Traditionally, tolerance allocation and scheduling have been dealt with separately in the literature. The aim of tolerance allocation is to minimize the tolerance cost. When scheduling the sequence of product operations, the goal is to minimize the makespan, mean flow time, machine idle time, and machine idle time cost. Calculations of manufacturing costs derived separately using tolerance allocation and scheduling separately will not be accurate. Hence, in this work, component tolerance was allocated by minimizing both the manufacturing cost (sum of the tolerance and quality loss cost) and the machine idle time cost, considering the product sequence. A genetic algorithm (GA) was developed for allocating the tolerance of the components and determining the best product sequence of the scheduling. To illustrate the effectiveness of the proposed method, the results are compared with those obtained with existing wheel mounting assembly discussed in the literature
The origins and development of Zuwīla, Libyan Sahara: an archaeological and historical overview of an ancient oasis town and caravan centre
Zuwīla in southwestern Libya (Fazzān) was one of the most important early Islamic centres in the Central Sahara, but the archaeological correlates of the written sources for it have been little explored. This paper brings together for the first time a detailed consideration of the relevant historical and archaeological data, together with new AMS radiocarbon dates from several key monuments. The origins of the settlement at Zuwīla were pre-Islamic, but the town gained greater prominence in the early centuries of Arab rule of the Maghrib, culminating with the establishment of an Ibāḍī state ruled by the dynasty of the Banū Khaṭṭāb, with Zuwīla its capital. The historical sources and the accounts of early European travellers are discussed and archaeological work at Zuwīla is described (including the new radiocarbon dates). A short gazetteer of archaeological monuments is provided as an appendix. Comparisons and contrasts are also drawn between Zuwīla and other oases of the ash-Sharqiyāt region of Fazzān. The final section of the paper presents a series of models based on the available evidence, tracing the evolution and decline of this remarkable site
Comprehensive analysis of epigenetic clocks reveals associations between disproportionate biological ageing and hippocampal volume
The concept of age acceleration, the difference between biological age and chronological age, is of growing interest, particularly with respect to age-related disorders, such as Alzheimer’s Disease (AD). Whilst studies have reported associations with AD risk and related phenotypes, there remains a lack of consensus on these associations. Here we aimed to comprehensively investigate the relationship between five recognised measures of age acceleration, based on DNA methylation patterns (DNAm age), and cross-sectional and longitudinal cognition and AD-related neuroimaging phenotypes (volumetric MRI and Amyloid-β PET) in the Australian Imaging, Biomarkers and Lifestyle (AIBL) and the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Significant associations were observed between age acceleration using the Hannum epigenetic clock and cross-sectional hippocampal volume in AIBL and replicated in ADNI. In AIBL, several other findings were observed cross-sectionally, including a significant association between hippocampal volume and the Hannum and Phenoage epigenetic clocks. Further, significant associations were also observed between hippocampal volume and the Zhang and Phenoage epigenetic clocks within Amyloid-β positive individuals. However, these were not validated within the ADNI cohort. No associations between age acceleration and other Alzheimer’s disease-related phenotypes, including measures of cognition or brain Amyloid-β burden, were observed, and there was no association with longitudinal change in any phenotype. This study presents a link between age acceleration, as determined using DNA methylation, and hippocampal volume that was statistically significant across two highly characterised cohorts. The results presented in this study contribute to a growing literature that supports the role of epigenetic modifications in ageing and AD-related phenotypes
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