924 research outputs found
Parent/Caregiver Lack of Knowledge: A Barrier for Youth Swimming Ability?
This study examined how a parent’s lack of knowledge of potential opportunities and barriers may restrict the child’s opportunity to learn how to swim. A survey was completed in multiple urban areas (N=524), where parents/caregivers reported their child’s swimming ability, as well as the parent’s knowledge of possible barriers to their child’s participation in swimming. ANOVA results suggested that the only significant difference between the presence of barriers groupings for child’s swimming ability were based on the availability of a pool and ease of access. For potential barriers examined, the group who lacked of barriers had a significantly lower perception of their child’s swimming ability than the group who recognized barriers (p\u3c.001 for all), suggesting that while physical barriers may play a role in a child’s likelihood of learning to swim, the most significant barrier may be the involvement and knowledge of the parent/caregiver
The Development of Swimming Skills for African American Youth: Parent and Caregiver Perceptions of Barriers and Motivations
African American urban youth participate in swimming at an alarmingly low rate with 69% self-reporting low or no swimming skill (Irwin, Irwin, Martin,&Ross, 2010). This lack of participation translates into a drowning rate three times as high as than their White/European American peers (CDC, 2009). To investigate this issue, 12 focus groups were conducted with parents and caregivers of swimming and nonswimming children at YMCAs in six American cities. Parents/caregivers who self-identified as Black or African American shared attitudes and values that impacted their child\u27s swimming participation. Some participants in the study identified structural barriers such as a lack of time, money, or facilities. Others shared attitudes of fear and discomfort in being in and around water. Parent/caregiver attitudes had a substantial impact on children\u27s opportunities to learn to swim. There was evidence that cultural expectations about swimming impacted the choices parents in this study made regarding swimming participation. Focus group participants shared strategies of effective messaging to influence caregiver attitudes to positively impact participation. © 2014 Human Kinetics, Inc
Racial-group differences in IQ in the Minnesota Transracial Adoption Study: A reply to Levin and
The etiology of racial differences in intelligence and achievement is one of the most heated areas of social science research. In this article, we respond to criticisms by Levin and Lynn of our 1992 follow-up study of IQ and achievement in a sample of transracial adoptees and their families, in particular to their assertion that our results provide strong support for a genetic etiology underlying racial differences in measured intelligence. In that follow-up, as well as in publications from the original study In this article, we address a number of issues raised in Levin's and Lynn's critiques, including the magnitude of adoptee racial-group differences in IQ and achievement, the inclusion of white and Asian/Indian adoptee groups in such analyses, the confounding of important early environmental influences with race differences, the confusion of withingroup and between-group influences on IQ, the regional U.S. differences in AfricanAmerican norms for IQ and achievement, the effects of renormed IQ tests on adoptee group differences, and the nature of the available evidence regarding a genetic hypothesis for racial differences in intelligence. We argue that, contrary to Levin's and Lynn's assertions, results from the Minnesota Transracial Adoption Study provide little or no conclusive evidence for genetic influences underlying racial differences in intelligence and achievement. Racial-group differences in intelligence and achievement are often observed but seldom explained to anyone's satisfaction. A variety of etiological speculations have been offered to explain such differences. These have included environmental factors, such as the pervasive effects of poverty The authors wish to acknowledge the helpful comments of an anonymous reviewer. Correspondence and requests for reprints should be sent t
Exploring Halo Substructure with Giant Stars. VI. Extended Distributions of Giant Stars Around the Carina Dwarf Spheroidal Galaxy -- How Reliable Are They?
The question of the existence of active tidal disruption around various dSph
galaxies remains controversial. That debate often centers on the nature (bound
vs. unbound) of extended populations of stars. However, the more fundamental
issue of the very existence of the extended populations is still contentious.
We present an evaluation of the debate centering on one particular dSph,
Carina, for which claims both for and against the existence of stars beyond the
King radius have been made. Our review includes an examination of all previous
studies bearing on the Carina radial profile and shows that the survey method
which achieves the highest detected dSph signal-to-background in the outer
parts of the galaxy is the Washington M, T2 + DDO51 (MTD) filter approach from
Paper II in this series. We then address statistical methods used to evaluate
the reliability of MTD surveys in the presence of photometric errors and for
which a new, a posteriori statistical analysis methodology is provided.
Finally, these statistical methods are tested by new spectroscopy of stars in
the MTD-selected Carina candidate sample. Of 74 candidate giants with follow-up
spectroscopy, the MTD technique identified 61 new Carina members, including 8
stars outside the King radius. From a sample of 29 stars not initially
identified as candidate Carina giants but that lie just outside of our
selection criteria, 12 have radial velocities consistent with membership,
including 5 extratidal stars. Carina is shown to have an extended population of
giant stars extending to a major axis radius of 40' (1.44x the nominal King
radius).Comment: 56 pages, 10 figures. Submitted to the Astronomical Journal, 2004 Sep
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The VMC survey - XVII : The proper motions of the Small Magellanic Cloud and the Milky Way globular cluster 47 Tucanae
In this study we use multi-epoch near-infrared observations from the VISTA survey of the Magellanic Cloud system (VMC) to measure the proper motion of different stellar populations in a tile of 1.5 deg sq. in size in the direction of the Galactic globular cluster 47 Tuc. We obtain the proper motion of the cluster itself, of the Small Magellanic Cloud (SMC), and of the field Milky Way stars. Stars of the three main stellar components are selected from their spatial distribution and their distribution in colour-magnitude diagrams. Their average coordinate displacement is computed from the difference between multiple Ks-band observations for stars as faint as Ks=19 mag. Proper motions are derived from the slope of the best-fitting line among 10 VMC epochs over a time baseline of ~1 yr. Background galaxies are used to calibrate the absolute astrometric reference frame. The resulting absolute proper motion of 47 Tuc is (mu_alpha cos(delta), mu_delta)=(+7.26+/-0.03, -1.25+/-0.03) mas/yr. This measurement refers to about 35000 sources distributed between 10 and 60 arcmin from the cluster centre. For the SMC we obtain (mu_alpha cos(delta), mu_delta)=(+1.16+/-0.07, -0.81+/-0.07) mas/yr from about 5250 red clump and red giant branch stars. The absolute proper motion of the Milky Way population in the line-of-sight (l =305.9, b =-44.9) of this VISTA tile is (mu_alpha cos(delta), mu_delta)=(+10.22+/-0.14, -1.27+/-0.12) mas/yr and results from about 4000 sources. Systematic uncertainties associated to the astrometric reference system are 0.18 mas/yr. Thanks to the proper motion we detect 47 Tuc stars beyond its tidal radius.Peer reviewe
The Monitor project: JW 380 -- a 0.26, 0.15 Msol pre main sequence eclipsing binary in the Orion Nebula Cluster
We report the discovery of a low-mass (0.26 +/- 0.02, 0.15 +/- 0.01 Msol)
pre-main-sequence eclipsing binary with a 5.3 day orbital period. JW 380 was
detected as part of a high-cadence time-resolved photometric survey (the
Monitor project) using the 2.5m Isaac Newton Telescope and Wide Field Camera
for a survey of a single field in the Orion Nebula Cluster (ONC) region in V
and i bands. The star is assigned a 99 per cent membership probability from
proper motion measurements, and radial velocity observations indicate a
systemic velocity within 1 sigma of that of the ONC. Modelling of the combined
light and radial velocity curves of the system gave stellar radii of 1.19 +0.04
-0.18 Rsol and 0.90 +0.17 -0.03 Rsol for the primary and secondary, with a
significant third light contribution which is also visible as a third peak in
the cross-correlation functions used to derive radial velocities. The masses
and radii appear to be consistent with stellar models for 2-3 Myr age from
several authors, within the present observational errors. These observations
probe an important region of mass-radius parameter space, where there are
currently only a handful of known pre-main-sequence eclipsing binary systems
with precise measurements available in the literature.Comment: 11 pages, 9 figures, accepted for publication in MNRA
Exploring Halo Substructure with Giant Stars IV: The Extended Structure of the Ursa Minor Dwarf Spheroidal
We present a large area photometric survey of the Ursa Minor dSph. We
identify UMi giant star candidates extending to ~3 deg from the center of the
dSph. Comparison to previous catalogues of stars within the tidal radius of UMi
suggests that our photometric luminosity classification is 100% accurate. Over
a large fraction of the survey area, blue horizontal branch stars associated
with UMi can also be identified. The spatial distribution of both the UMi giant
stars and the BHB stars are remarkably similar, and a large fraction of both
samples of stars are found outside the tidal radius of UMi. An isodensity
contour map of the stars within the tidal radius of UMi reveals two
morphological peculiarities: (1) The highest density of dSph stars is offset
from the center of symmetry of the outer isodensity contours. (2) The overall
shape of the outer contours appear S-shaped. We find that previously determined
King profiles with ~50' tidal radii do not fit well the distribution of our UMi
stars. A King profile with a larger tidal radius produces a reasonable fit,
however a power law with index -3 provides a better fit for radii > 20'. The
existence of UMi stars at large distances from the core of the galaxy, the
peculiar morphology of the dSph within its tidal radius, and the shape of its
surface density profile all suggest that UMi is evolving significantly due to
the tidal influence of the Milky Way. However, the photometric data on UMi
stars alone does not allow us to determine if the candidate extratidal stars
are now unbound or if they remain bound to the dSph within an extended dark
matter halo. (Abridged)Comment: accepted by AJ, 32 pages, 15 figures, emulateapj5 styl
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