1,180 research outputs found
Validity and reliability of a modified English version of the Physical Activity Questionnaire for Adolescents
Background: Adaptation of physical activity self-report questionnaires is sometimes required to reflect the activity behaviours of diverse populations. The processes used to modify self-report questionnaires though are typically underreported. This two-phased study used a formative approach to investigate the validity and reliability of the Physical Activity Questionnaire for Adolescents (PAQ-A) in English youth. Phase one examined test content and response process validity and subsequently informed a modified version of the PAQ-A. Phase two assessed the validity and reliability of the modified PAQ-A. Methods: In phase one, focus groups (n=5) were conducted with adolescents (n=20) to investigate test content and response processes of the original PAQ-A. Based on evidence gathered in phase one, a modified version of the questionnaire was administered to participants (n=169, 14.5±1.7 years) in phase two. Internal consistency and test-retest reliability were assessed using Cronbach’s alpha and intra-class correlations, respectively. Spearman correlations were used to assess associations between modified PAQ-A scores and accelerometer-derived physical activity, self-reported fitness and physical activity self-efficacy. Results: Phase one revealed that the original PAQ-A was unrepresentative for English youth and that item comprehension varied. Contextual and population/cultural-specific modifications were made to the PAQ-A for use in the subsequent phase. In phase two, modified PAQ-A scores had acceptable internal consistency (α=0.72) and test-retest reliability (ICC=0.78). Modified PAQ-A scores were significantly associated with objectively assessed moderate-to-vigorous physical activity (r=0.39), total physical activity (r=0.42), self-reported fitness (r=0.35), and physical activity self-efficacy (r=0.32) (p≤0.01). Conclusions: The modified PAQ-A had acceptable internal consistency and test-retest reliability. Modified PAQ-A scores displayed weak-to-moderate correlations with objectively measured physical activity, self-reported fitness, and self-efficacy providing evidence of satisfactory criterion and construct validity, respectively. Further testing with more diverse English samples is recommended to provide a more complete assessment of the tool
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Motion Correction Resolved for MRI via Multi-Tasking: A Simultaneous Reconstruction and Registration Approach
The prolonged time required to form an MR image continues to impose different challenges at both theoretical and clinical levels. With this motivation in mind, this work addresses a central topic in MRI, which is how to correct the motion problem, through a new multitask optimisation
framework. The significance is that by tackling the reconstruction and registration tasks simultaneously and jointly one can exploit their strong correlation reducing error propagations and resulting in a significant motion correction. The clinical potentials of our approach are reflected in having higher image quality with fewer artefacts whilst keeping fine details. We evaluate our approach through a set of quantitative and qualitative experimental results
Using a Temporal-Causal Network Model for Computational Analysis of the Effect of Social Media Influencers on the Worldwide Interest in Veganism
Major Merging: The Way to Make a Massive, Passive Galaxy
We analyze the projected axial ratio distribution, p(b/a), of galaxies that
were spectroscopically selected from the Sloan Digital Sky Survey (DR6) to have
low star-formation rates. For these quiescent galaxies we find a rather abrupt
change in p(b/a) at a stellar mass of ~10^{11} M_sol: at higher masses there
are hardly any galaxies with b/a<0.6, implying that essentially none of them
have disk-like intrinsic shapes and must be spheroidal. This transition mass is
~3-4 times higher than the threshold mass above which quiescent galaxies
dominate in number over star-forming galaxies, which suggests these mass scales
are unrelated. At masses lower than ~10^{11} M_sol, quiescent galaxies show a
large range in axial ratios, implying a mix of bulge- and disk-dominated
galaxies. Our result strongly suggests that major merging is the most
important, and perhaps only relevant, evolutionary channel to produce massive
(>10^{11} M_sol), quiescent galaxies, as it inevitably results in spheroids.Comment: Minor changes to match published version in ApJ Letter
Extragalactic Science, Cosmology and Galactic Archaeology with the Subaru Prime Focus Spectrograph (PFS)
The Subaru Prime Focus Spectrograph (PFS) is a massively-multiplexed
fiber-fed optical and near-infrared 3-arm spectrograph (N_fiber=2400,
380<lambda<1260nm, 1.3 degree diameter FoV), offering unique opportunities in
survey astronomy. Here we summarize the science case feasible for a survey of
Subaru 300 nights. We describe plans to constrain the nature of dark energy via
a survey of emission line galaxies spanning a comoving volume of 9.3 (Gpc/h)^3
in the redshift range 0.8<z<2.4. In each of 6 redshift bins, the cosmological
distances will be measured to 3% precision via BAO, and redshift-space
distortions will be used to constrain structure growth to 6% precision. In the
GA program, radial velocities and chemical abundances of stars in the Milky Way
and M31 will be used to infer the past assembly histories of spiral galaxies
and the structure of their dark matter halos. Data will be secured for 10^6
stars in the Galactic thick-disk, halo and tidal streams as faint as V~22,
including stars with V < 20 to complement the goals of the Gaia mission. A
medium-resolution mode with R = 5000 to be implemented in the red arm will
allow the measurement of multiple alpha-element abundances and more precise
velocities for Galactic stars, elucidating the detailed chemo-dynamical
structure and evolution of each of the main stellar components of the Milky Way
Galaxy and of its dwarf spheroidal galaxies. For the extragalactic program, our
simulations suggest the wide avelength range will be powerful in probing the
galaxy population and its clustering over a wide redshift range. We propose to
conduct a color-selected survey of 1<z<2 galaxies and AGN over 16 deg^2 to
J~23.4, yielding a fair sample of galaxies with stellar masses above ~10^{10}Ms
at z~2. A two-tiered survey of higher redshift LBGs and LAEs will quantify the
properties of early systems close to the reionization epoch.Comment: This document describes the scientific program and requirements for
the Subaru Prime Focus Spectrograph (PFS) project. Made significant revision
based on studies for the Preliminary Design Review (PRD) held in Feb 2013.
The higher-resolution paper file is available from
http://member.ipmu.jp/masahiro.takada/pfs_astroph_rv.pd
The Origin of the 24-micron Excess in Red Galaxies
Observations with the Spitzer Space Telescope have revealed a population of
red-sequence galaxies with a significant excess in their 24-micron emission
compared to what is expected from an old stellar population. We identify 900
red galaxies with 0.15<z<0.3 from the AGN and Galaxy Evolution Survey (AGES)
selected from the NOAO Deep Wide-Field Survey Bootes field. Using Spitzer/MIPS,
we classify 89 (~10%) with 24-micron infrared excess (f24>0.3 mJy). We
determine the prevalence of AGN and star-formation activity in all the AGES
galaxies using optical line diagnostics and mid-IR color-color criteria. Using
the IRAC color-color diagram from the IRAC Shallow Survey, we find that 64% of
the 24-micron excess red galaxies are likely to have strong PAH emission
features in the 8-micron IRAC band. This fraction is significantly larger than
the 5% of red galaxies with f24<0.3 mJy that are estimated to have strong PAH
emission, suggesting that the infrared emission is largely due to
star-formation processes. Only 15% of the 24-micron excess red galaxies have
optical line diagnostics characteristic of star-formation (64% are classified
as AGN and 21% are unclassifiable). The difference between the optical and
infrared results suggest that both AGN and star-formation activity is occurring
simultaneously in many of the 24-micron excess red galaxies. These results
should serve as a warning to studies that exclusively use optical line
diagnostics to determine the dominant emission mechanism in the infrared and
other bands. We find that ~40% of the 24-micron excess red galaxies are edge-on
spiral galaxies with high optical extinctions. The remaining sources are likely
to be red galaxies whose 24-micron emission comes from a combination of
obscured AGN and star-formation activity.Comment: ApJ, accepted; 11 pages, 7 figures; corrected reference to IRAC
Shallow Survey in abstrac
Increasing Incidence of Listeriosis in France and Other European Countries
The cause of an increase among persons >60 years of age in France is unknown
Understanding consumer demand for new transport technologies and services, and implications for the future of mobility
The transport sector is witnessing unprecedented levels of disruption.
Privately owned cars that operate on internal combustion engines have been the
dominant modes of passenger transport for much of the last century. However,
recent advances in transport technologies and services, such as the development
of autonomous vehicles, the emergence of shared mobility services, and the
commercialization of alternative fuel vehicle technologies, promise to
revolutionise how humans travel. The implications are profound: some have
predicted the end of private car dependent Western societies, others have
portended greater suburbanization than has ever been observed before. If
transport systems are to fulfil current and future needs of different
subpopulations, and satisfy short and long-term societal objectives, it is
imperative that we comprehend the many factors that shape individual behaviour.
This chapter introduces the technologies and services most likely to disrupt
prevailing practices in the transport sector. We review past studies that have
examined current and future demand for these new technologies and services, and
their likely short and long-term impacts on extant mobility patterns. We
conclude with a summary of what these new technologies and services might mean
for the future of mobility.Comment: 15 pages, 0 figures, book chapte
The current status of cognitive behavioral therapy for eating disorders: Marking the 51st Annual Convention of the Association of Behavioral and Cognitive Therapies
This Virtual Issue of the International Journal of Eating Disorders (IJED)marks the 51st Annual Convention of the Association for Behavioraland Cognitive Therapies (ABCT), held in San Diego in November 2017.It consists of a set of recent papers published in IJED, providing keyevidence about the current status of cognitive behavior therapy foreating disorders (CBT-ED)We hope that such access will support ABCT members in puttingthe San Diego meeting material into context. We also hope that beingbrought up to date via both the conference and the Virtual Issue willencourage you to develop your own thoughts and experiences intoresearch of your own, and that you will submit your research to IJEDto add to that evidence base. Nobody can pretend that CBT-ED isperfect, despite its strong standing in the field. We need a multitude ofperspectives, new ideas, and a willingness to grow the field, and weknow that ABCT is a perfect organization for advancing our evidencebase for CBT-ED
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