6,178 research outputs found
The Properties of Satellite Galaxies in External Systems. I. Morphology and Structural Parameters
We present the first results of an ongoing project to study the
morphological, kinematical, dynamical, and chemical properties of satellite
galaxies of external giant spiral galaxies. The sample of objects has been
selected from the catalogue by Zaritsky et al. (1997). The paper analyzes the
morphology and structural parameters of a subsample of 60 such objects. The
satellites span a great variety of morphologies and surface brightness
profiles. About two thirds of the sample are spirals and irregulars, the
remaining third being early-types. Some cases showing interaction between pairs
of satellites are presented and briefly discussed.Comment: Accepted for publication in Astrophys. Journal Supp. Se
Occupational therapists as contributors to health promotion
Objective: This study was undertaken to explore the views of occupational therapists concerning their competences in health promotion, and their perceptions of how they apply these competences in their daily work. The study also elicited their views on the contributions that occupational therapists could make to health promotion if given the opportunity. Methods: Data were collected in five focus-group discussions with 24 occupational therapists. These discussions were tape recorded and transcribed verbatim; data were analysed using qualitative content analysis. Results: The main findings are that the informants took an individualized salutogenic approach in their work and rarely engaged in health promotion on a systemic or societal level. They believed that their patients and collaborating partners, as well as public officials, remained unaware of their competences in health promotion. Conclusions: The findings of this study could enrich the discussion among occupational therapists on how they could make a more significant contribution to health promotion on a broader level
Seeing Galaxies Through Thick & Thin. III. HST Imaging of the Dust in Backlit Spiral Galaxies
We present analysis of WFPC2 imaging of two spiral galaxies partially backlit
by E/S0 systems in the pairs AM1316-241 and AM0500-620, and the spiral
foreground system in NGC 1275. Images in B and I are used to determine the
reddening curve of in these systems. The spiral component of AM1316-241 shows
dust strongly concentrated in discrete arms, with a reddening law very close to
the Milky Way mean. The dust distribution is scale-free between about 100 pc
and the arm scale. The spiral in AM0500-620 shows dust concentrated in arms and
interarm spurs, with measurable interarm extinction as well. Although its dust
properties are less well-determined, we find evidence for a steeper extinction
law here. The shape of the reddening law suggests that, at least in AM1316-241,
we have resolved most of the dust structure. In AM0500-620, the slope of the
fractal perimeter-scale relation steepens systematically from low to high
extinction. In AM1316-241, we cannot determine a unique fractal dimension from
the defining area-perimeter relation, so the projected dust distribution is
best defined as fractal-like. In neither galaxy do we see regions even on
single-pixel scales in spiral arms with AB > 2.5. The measurements in NGC 1275
are compromised by our lack of independent knowledge of the foreground system's
light distribution, but masked sampling of the absorption suggests an effective
reddening curve much flatter than the Milky Way mean (perhaps indicating that
the foreground system has been affected by immersion in the hot intracluster
gas).Comment: Astronomical Journal, in press. 13 figures. Full-size PostScript
figures available at http://www.astr.ua.edu/preprints/kee
Re-description of Togwoteeus biceps (Arachnida, Opiliones, Sclerosomatidae) with notes on its morphology, karyology and phenology.
The harvestman genus Togwoteeus Roewer 1952 is monotypic. Its only species, T. biceps
(Thorell 1877), is known from throughout western Canada and USA and is newly recorded from California,
Nebraska, Nevada, Oregon, South Dakota, and Utah. This species occurs below 500 m and at the
highest elevation (4100 m) of any recorded harvestman in North America. It ranges from about 33-54°
N and exhibits considerable variation in its morphological measurements. Twenty-seven such measurements
are summarized for 80 males and 74 females. Ultrastructural details of the integument, appendages
and genital organs are presented. The karyotype is 2n = 22 for both sexes. All chromosomes are metacentric
and obvious sex chromosomes were not detected. Immature T. biceps overwinter and reach adulthood
in late spring or early summer. Adults die by late fall
A Hubble Space Telescope Snapshot Survey of Dynamically Close Galaxy Pairs in the CNOC2 Redshift Survey
We compare the structural properties of two classes of galaxies at
intermediate redshift: those in dynamically close galaxy pairs, and those which
are isolated. Both samples are selected from the CNOC2 Redshift Survey, and
have redshifts in the range 0.1 < z <0.6. Hubble Space Telescope WFPC2 images
were acquired as part of a snapshot survey, and were used to measure bulge
fraction and asymmetry for these galaxies. We find that paired and isolated
galaxies have identical distributions of bulge fractions. Conversely, we find
that paired galaxies are much more likely to be asymmetric (R_T+R_A >= 0.13)
than isolated galaxies. Assuming that half of these pairs are unlikely to be
close enough to merge, we estimate that 40% +/- 11% of merging galaxies are
asymmetric, compared with 9% +/- 3% of isolated galaxies. The difference is
even more striking for strongly asymmetric (R_T+R_A >= 0.16) galaxies: 25% +/-
8% for merging galaxies versus 1% +/- 1% for isolated galaxies. We find that
strongly asymmetric paired galaxies are very blue, with rest-frame B-R colors
close to 0.80, compared with a mean (B-R)_0 of 1.24 for all paired galaxies. In
addition, asymmetric galaxies in pairs have strong [OII]3727 emission lines. We
conclude that close to half of the galaxy pairs in our sample are in the
process of merging, and that most of these mergers are accompanied by triggered
star formation.Comment: Accepted for publication in the Astronomical Journal. 40 pages,
including 15 figures. For full resolution version, please see
http://www.trentu.ca/physics/dpatton/hstpairs
DIFFERENT TECHNICAL STRATEGIES AND BIOMECHANICAL ASPECTS OF DOUBLE POLlNG IN ELITE CROSS-COUNTRY SKIING
The purpose of this study was to analyse double poling (DP) regarding biomechanical performance determinants and different strategies. Eleven elite cross-country skiers performed DP at 85% of their maximal DP velocity (V85%) during roller skiing (treadmill; 1° inclination) while pole forces and selected joint angles were recorded. A 2D video evaluation categorised skiers into two different DP strategy groups. Strategy A group showed higher elbow (p < 0.01) and hip flexion angular velocities, smaller minimum elbow, knee and hip angles, higher peak pole force, shorter time to peak pole force and a longer relati.ve recovery time (p < 0.05), variables to which V85% was significantly correlated (p < 0.05). DP strategy A provides an effective model for technique and specific strength training while its physiological economy has to be further investigated
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