1,797 research outputs found
Report of the Integrated Stroke Care Workshop
The Stroke Project has been underway since October 2000. This workshop represented the first mechanism where by issues surrounding the project have been addressed by the multi- disciplinary stroke team and the Darent Valley Hospital Staff. Approximately 35 members of staff attended the workshop, demonstrating the high level of interest and ownership. Currently, the hospital receives an average eight or nine new stroke admissions a week. The turnover is such that patients suffering from stroke account for around 22-23 occupied beds in the acute hospital at any point in time. In the past the Acute Trust had had a lead Stroke Physician responsible for 20 designated stroke beds within a stroke unit. In that system many (but not all) cases of acute stroke admitted under the General Physicians would have been referred to the stroke unit and had their acute care and acute rehabilitation provided on site in that unit. At that time the overall number of beds occupied by cases of stroke was around 28- 29
Structure prediction of crystals, surfaces and nanoparticles
We review the current techniques used in the prediction of crystal structures and their surfaces and of the structures of nanoparticles. The main classes of search algorithm and energy function are summarized, and we discuss the growing role of methods based on machine learning. We illustrate the current status of the field with examples taken from metallic, inorganic and organic systems. This article is part of a discussion meeting issue 'Dynamic in situ microscopy relating structure and function'
Directives and Academics: educational developers, technology and the right support
There can be ‘an army of people involved in the development of academics as teachers’
(Ling & CADAC, 2009) and the role of Educational Developers with technological
expertise is vital to the uptake and creative use of educational technologies in learning
contexts (Oliver, 2005). Even so, technology plays only a part in the teaching and learning
experience and must be underpinned with pedagogical wherewithal. At Victoria University
(VU) in Melbourne, a new VU Agenda expects the university to be known for educational
programmes ‘that maximise opportunities for blended and eLearning’.
This discussion examines the support available to staff using technologies for teaching. The
discussion covers two examples from different faculties where teaching staff have needed
to comply with Faculty or School directives to use particular university-supported
technologies (Lectopia and GradeMark). The comments about staff uptake of technologies
draw on general themes from evaluations administered in each faculty to gauge the
effectiveness of the technologies for teaching and to identify further professional
development needs. Unsurprisingly, the findings show that, without intensive and timely
support tailored to the specific requirements of academics, without academics having both
an understanding of the reason for the mandating of a technology as well as an ability to
influence that uptake, academics are likely to find ways to resist authoritarian directives.
The danger of encouraging academics’ uptake of educational technologies without broader
educational development support to encourage good teaching practices that integrate
technology and good curriculum design became clear from the dat
An Empirical Measure of the Rate of White Dwarf Cooling in 47 Tucanae
We present an empirical determination of the white dwarf cooling sequence in
the globular cluster 47 Tucanae. Using spectral models, we determine
temperatures for 887 objects from Wide Field Camera 3 data, as well as 292
objects from data taken with the Advanced Camera for Surveys. We make the
assumption that the rate of white dwarf formation in the cluster is constant.
Stellar evolution models are then used to determine the rate at which objects
are leaving the main sequence, which must be the same as the rate at which
objects are arriving on the white dwarf sequence in our field. The result is an
empirically derived relation between temperature () and time () on
the white dwarf cooling sequence. Comparing this result to theoretical cooling
models, we find general agreement with the expected slopes between 20,000K and
30,000K and between 6,000K and 20,000K, but the transition to the Mestel
cooling rate of is found to occur at hotter
temperatures, and more abruptly than is predicted by any of these models.Comment: 10 pages, 16 figures, accepted for publication in Ap
Mitochondrial Function as a Potential Tool for Assessing Function, Quality and Adulteration in Medicinal Herbal Teas
Quality control has been a significant issue in herbal medicine since herbs became widely used to heal. With the advent of modern technologies, evaluating the quality of medicinal herbs has become more sophisticated but so have the methods of adulterating them. In this paper we undertook a comprehensive literature search to identify the key analytical techniques used in the quality assurance of herbal medicine, reviewing their uses and limitations. We also present a new tool, based on mitochondrial profiling, that can be used to measure medicinal herbal quality. Besides being fundamental to the energy metabolism required for most cellular activities, mitochondria play a direct role in cellular signalling, apoptosis, stress responses, inflammation, cancer, ageing, and neurological function, mirroring some of the most common reasons people take herbal medicines. A fingerprint of the specific mitochondrial effects of medicinal herbs can be documented in order to assess their potential efficacy, detect adulterations that modulate these effects and determine the relative potency of batches. Furthermore, through this method it will be possible to assess whole herbs or complex formulas thus avoiding the issues inherent in identifying active ingredients which may be complex or unknown. Thus, while current analytical methods focus on determining the chemical quality of herbal medicines, including adulteration and contamination, mitochondrial functional analysis offers a new way of determining the quality of plant derived products that is more closely linked to the biological activity of a product and its potential clinical effectiveness
Swift-BAT Survey of Galactic Sources: Catalog and Properties of the populations
We study the populations of X-ray sources in the Milky Way in the 15-55 keV
band using a deep survey with the BAT instrument aboard the Swift observatory.
We present the logN-logS distributions of the various source types and we
analyze their variability and spectra. For the low-mass X-ray binaries (LMXBs)
and the high-mass X-ray binaries (HMXBs) we derive the luminosity functions to
a limiting luminosity of L_X~7 times10^{34} erg s/s. Our results confirm the
previously found flattening of the LMXB luminosity function below a luminosity
of L_X~10^{37} erg s/s. The luminosity function of the HMXBs is found to be
significantly flatter in the 15-55 keV band than in the 2-10 keV band. From the
luminosity functions we estimate the ratios of the hard X-ray luminosity from
HMXBs to the star-formation rate, and the LMXB luminosity to the stellar mass.
We use these to estimate the X-ray emissivity in the local universe from X-ray
binaries and show that it constitutes only a small fraction of the hard X-ray
background.Comment: 21 pages, accepted by Ap
Double bubble secondary building units used as a structural motif for enhanced electron-hole separation in solids
A structural motif designed for enhancing electron–hole separation in semiconducting composite materials, the so-called double bubble, is introduced. The addition of silicon carbide in the construction of heterogeneous double bubble systems, along with zinc oxide and gallium nitride, yields electronic structures that are favourable for electron–hole separation. The standard formation enthalpies of such systems are comparable with those of fullerenes, suggesting that these systems would be achievable and of direct benefit to photovoltaic and electrochemical applications such as water splitting; with the (SiC)12@(ZnO)48 proving to be the most promising building block for future functional composite materials
<i>‘What retention’ means to me</i>: the position of the adult learner in student retention
Studies of student retention and progression overwhelmingly appear adopt definitions that place the institution, rather than the student, at the centre. Retention is most often conceived in terms of linear and continuous progress between institutionally identified start and end points.
This paper reports on research that considered data from 38 in-depth interviews conducted with individuals who had characteristics often associated with non-traditional engagement in higher education who between 2006 and 2010 had studied an ‘Introduction to HE’ module at one distance higher education institution, some of whom had progressed to further study at that institution, some of whom had not. The research deployed a life histories approach to seek a finer grained understanding of how individuals conceptualise their own learning journey and experience, in order to reflect on institutional conceptions of student retention.
The findings highlight potential anomalies hidden within institutional retention rates – large proportions of the interview participants who were not ‘retained’ by the institution reported successful progression to and in other learning institutions and environments, both formal and informal. Nearly all described positive perspectives on lifelong learning which were either engendered or improved by the learning undertaken. This attests to the complexity of individuals’ lives and provides clear evidence that institution-centric definitions of retention and progression are insufficient to create truly meaningful understanding of successful individual learning journeys and experiences. It is argued that only through careful consideration of the lived experience of students and a re-conception of measures of retention, will we be able to offer real insight into improving student retention
The Globular Cluster Systems around NGC 3311 and NGC 3309
We present extensive new photometry in (g',i') of the large globular cluster
(GC) system around NGC 3311, the central cD galaxy in the Hydra cluster. Our
GMOS data cover a 5.5' field of view and reach a limiting magnitude i' = 26,
about 0.5 magnitude fainter than the turnover point of the GC luminosity
function. We find that NGC 3311 has a huge population of ~16, 000 GCs, closely
similar to the prototypical high specific frequency Virgo giant M87. The
color-magnitude distribution shows that the metal-poor blue GC sequence and the
metal-richer red sequence are both present, with nearly equal numbers of
clusters. Bimodal fits to the color distributions confirm that the blue
sequence shows the same trend of progressively increasing metallicity with GC
mass that has previously been found in many other large galaxies; the
correlation we find corresponds to a scaling of GC metallicity with mass of Z ~
M^0.6 . By contrast, the red sequence shows no change of mean metallicity with
mass, but it shows an upward extension to much higher than normal luminosity
into the UCD-like range, strengthening the potential connections between
massive GCs and UCDs. The GC luminosity function, which we measure down to the
turnover point at M_I = -8.4, also has a normal form like those in other giant
ellipticals. Within the Hydra field, another giant elliptical NGC 3309 is
sitting just 100" from the cD NGC 3311. We use our data to solve simultaneously
for the spatial structure and total GC populations of both galaxies at once.
Their specific frequencies are S_N (NGC 3311) = 12.5 +/- 1.5 and S_N (NGC 3309)
= 0.6 +/-0.4. NGC 3311 is completely dominant and entirely comparable with
other cD-type systems such as M87 in Virgo.Comment: 15 pages, 15 figures. Accepted to the Astrophysical Journal. Version
with higher resolution figures is available at
http://www.thewehners.net/astro/papers/wehner_n3311_highres.pd
Deep HST Imaging in NGC 6397: Stellar Dynamics
Multi-epoch observations with ACS on HST provide a unique and comprehensive
probe of stellar dynamics within NGC 6397. We are able to confront analytic
models of the globular cluster with the observed stellar proper motions. The
measured proper motions probe well along the main sequence from 0.8 to below
0.1 M as well as white dwarfs younger than one gigayear. The observed
field lies just beyond the half-light radius where standard models of globular
cluster dynamics (e.g. based on a lowered Maxwellian phase-space distribution)
make very robust predictions for the stellar proper motions as a function of
mass. The observed proper motions show no evidence for anisotropy in the
velocity distribution; furthermore, the observations agree in detail with a
straightforward model of the stellar distribution function. We do not find any
evidence that the young white dwarfs have received a natal kick in
contradiction with earlier results. Using the observed proper motions of the
main-sequence stars, we obtain a kinematic estimate of the distance to NGC 6397
of kpc and a mass of the cluster of at the photometric distance of 2.53 kpc. One of the
main-sequence stars appears to travel on a trajectory that will escape the
cluster, yielding an estimate of the evaporation timescale, over which the
number of stars in the cluster decreases by a factor of e, of about 3 Gyr. The
proper motions of the youngest white dwarfs appear to resemble those of the
most massive main-sequence stars, providing the first direct constraint on the
relaxation time of the stars in a globular cluster of greater than or about 0.7
Gyr.Comment: 25 pages, 20 figures, accepted for publication in Astrophysical
Journa
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