1,136 research outputs found
Increasing the Verbal Response Rate of a Mentally Retarded Girl
This investigation was instigated to assess the effectiveness of a systematic application of reinforcement on the verbal response rate of a withdrawn, educable mentally retarded student in a junior high school special education class. The purpose of this study was to test the following hypothesis: There will be no statistically significant difference in the subject\u27s verbal response rate between the baseline average and under conditions of systematic application of reinforcement
Distant field BHB stars and the mass of the Galaxy II: Photometry and spectroscopy of UKST candidates 16<B<19.5, 11<R<52 kpc
This is the second in a series of papers presenting a new calculation of the
mass of the Galaxy based on radial velocities and distances for a sample of
faint 16 < B < 21.3 field blue horizontal-branch (BHB) stars. We present
accurate BV CCD photometry and spectra for 142 candidate A-type stars selected
from ub_jr photometry of UK Schmidt telescope plates in six
high-Galactic-latitude fields. Classification of these candidates produces a
sample of 60 BHB stars at distances of 11-52 kpc from the Sun (mean 28 kpc),
with heliocentric line-of-sight velocities accurate to 15 km/s, and distance
errors < 10%. We provide a summary table listing coordinates and velocities of
these stars. The measured dispersion of the radial component of the
Galactocentric velocity for this sample is 108+-10 km/s, in agreement with a
recent study of the distant halo by Sirko and coworkers. Measurements of the Ca
II K line indicate that nearly all the stars are metal-poor with a mean [Fe/H]
= -1.8 with dispersion 0.5. Subsequent papers will describe a second survey of
BHBs to heliocentric distances 70 < R < 125 kpc and present a new estimate of
the mass of the Galaxy.Comment: 16 pages, 15 figures. Accepted for publication in MNRA
The Commensal Real-time ASKAP Fast Transients (CRAFT) survey
We are developing a purely commensal survey experiment for fast (<5s)
transient radio sources. Short-timescale transients are associated with the
most energetic and brightest single events in the Universe. Our objective is to
cover the enormous volume of transients parameter space made available by
ASKAP, with an unprecedented combination of sensitivity and field of view. Fast
timescale transients open new vistas on the physics of high brightness
temperature emission, extreme states of matter and the physics of strong
gravitational fields. In addition, the detection of extragalactic objects
affords us an entirely new and extremely sensitive probe on the huge reservoir
of baryons present in the IGM. We outline here our approach to the considerable
challenge involved in detecting fast transients, particularly the development
of hardware fast enough to dedisperse and search the ASKAP data stream at or
near real-time rates. Through CRAFT, ASKAP will provide the testbed of many of
the key technologies and survey modes proposed for high time resolution science
with the SKA.Comment: accepted for publication in PAS
The First Detection of Blue Straggler Stars in the Milky Way Bulge
We report the first detections of Blue Straggler Stars (BSS) in the bulge of
the Milky Way galaxy. Proper motions from extensive space-based observations
along a single sight-line allow us to separate a sufficiently clean and
well-characterized bulge sample that we are able to detect a small population
of bulge objects in the region of the color-magnitude diagram commonly occupied
young objects and blue strgglers. However, variability measurements of these
objects clearly establish that a fraction of them are blue stragglers. Out of
the 42 objects found in this region of the color-magnitude diagram, we estimate
that at least 18 are genuine BSS. We normalize the BSS population by our
estimate of the number of horizontal branch stars in the bulge in order to
compare the bulge to other stellar systems. The BSS fraction is clearly
discrepant from that found in stellar clusters. The blue straggler population
of dwarf spheroidals remains a subject of debate; some authors claim an
anticorrelation between the normalised blue straggler fraction and integrated
light. If this trend is real, then the bulge may extend it by three orders of
magnitude in mass. Conversely, we find that the genuinely young (~5Gy or
younger) population in the bulge, must be at most 3.4% under the most
conservative scenario for the BSS population.Comment: ApJ in press; 25 pages, 6 figures, 2 table
The changing of the guard: groupwork with people who have intellectual disabilities
This paper considers the impact of service systems on group activities. It describes an inter-professional groupwork project facilitated by a social worker and a community nurse. The project provided an emancipatory experience for a group of adults who had intellectual disabilities. The group was charged with the task of reviewing and updating the recruitment and interview processes used by a 'Learning Disability Partnership Board', when employing new support workers.
The paper begins with a brief history of intellectual disability and provides a context to the underpinning philosophical belief that people should be encouraged and supported to inhabit valued social roles no matter what disability they may have. It then identifies the ways in which the sponsoring health, education and social care services impacted on the creation and development of a groupwork project. It might have been expected that the nature of the intellectual disability would have been the major influence on group process. However the paper reveals that organisational constraints had a significant impact on group functioning. Issues including, staffing budgets and transport contracts impacted on group process and function.
The results of the project show how, with adequate support, people with intellectual disability can make important decisions that have long-reaching impacts on the services
TRPV4 antagonists ameliorate ventriculomegaly in a rat model of hydrocephalus
Hydrocephalus is a serious condition that impacts patients of all ages. The standards of care are surgical options to divert, or inhibit production of, cerebrospinal fluid; to date, there are no effective pharmaceutical treatments, to our knowledge. The causes vary widely, but one commonality of this condition is aberrations in salt and fluid balance. We have used a genetic model of hydrocephalus to show that ventriculomegaly can be alleviated by inhibition of the transient receptor potential vanilloid 4, a channel that is activated by changes in osmotic balance, temperature, pressure and inflammatory mediators. The TRPV4 antagonists do not appear to have adverse effects on the overall health of the WT or hydrocephalic animals
Why MSM in rural South African communities should be an HIV prevention research priority.
Research into HIV and men who have sex with men's (MSM) health in South Africa has been largely confined to the metropolitan centres. Only two studies were located making reference to MSM in rural contexts or same-sex behaviors among men in the same. There is growing recognition in South Africa that MSM are not only disproportionately affected by HIV and have been underserved by the country's national response, but that they contribute significantly to sustaining the high number of new infections recorded each year. We argue that to meet the objectives of the country's national strategic plan for HIV, STI and TB it is important we know how these behaviours may be contributing to the sustained rural HIV epidemic in the youngest age groups and determine what constitutes appropriate and feasible programmatic response that can be implemented in the country's public sector health services
The RR Lyrae Distance Scale
We review seven methods of measuring the absolute magnitude M_V of RR Lyrae
stars in light of the Hipparcos mission and other recent developments. We focus
on identifying possible systematic errors and rank the methods by relative
immunity to such errors. For the three most robust methods, statistical
parallax, trigonometric parallax, and cluster kinematics, we find M_V (at
[Fe/H] = -1.6) of 0.77 +/- 0.13, 0.71 +/- 0.15, 0.67 +/- 0.10. These methods
cluster consistently around 0.71 +/- 0.07. We find that Baade-Wesselink and
theoretical models both yield a broad range of possible values (0.45-0.70 and
0.45-0.65) due to systematic uncertainties in the temperature scale and input
physics. Main-sequence fitting gives a much brighter M_V = 0.45 +/- 0.04 but
this may be due to a difference in the metallicity scales of the cluster giants
and the calibrating subdwarfs. White-dwarf cooling-sequence fitting gives 0.67
+/- 0.13 and is potentially very robust, but at present is too new to be fully
tested for systematics. If the three most robust methods are combined with
Walker's mean measurement for 6 LMC clusters, V_{0,LMC} = 18.98 +/- 0.03 at
[Fe/H] = -1.9, then mu_{LMC} = 18.33 +/- 0.08.Comment: Invited review article to appear in: `Post-Hipparcos Cosmic Candles',
A. Heck & F. Caputo (Eds), Kluwer Academic Publ., Dordrecht, in press. 21
pages including 1 table; uses Kluwer's crckapb.sty LaTeX style file, enclose
Abundances of neutron-capture elements in G 24-25. A halo-population CH subgiant
The differences between the neutron-capture element abundances of halo stars
are important to our understanding of the nucleosynthesis of elements heavier
than the iron group. We present a detailed abundance analysis of carbon and
twelve neutron-capture elements from Sr up to Pb for a peculiar halo star
G24-25 with [Fe/H] = -1.4 in order to probe its origin. The equivalent widths
of unblended lines are measured from high resolution NOT/FIES spectra and used
to derive abundances based on Kurucz model atmospheres. In the case of CH, Pr,
Eu, Gd, and Pb lines, the abundances are derived by fitting synthetic profiles
to the observed spectra. Abundance analyses are performed both relative to the
Sun and to a normal halo star G16-20 that has similar stellar parameters as
G24-25. We find that G24-25 is a halo subgiant star with an unseen component.
It has large overabundances of carbon and heavy s-process elements and mild
overabundances of Eu and light s-process elements. This abundance distribution
is consistent with that of a typical CH giant. The abundance pattern can be
explained by mass transfer from a former asymptotic giant branch component,
which is now a white dwarf.Comment: 11 pages, 9 figures, accepted for publication in A&
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