381 research outputs found
The Construction Of Education as an Area of Study at Murdoch University: 1974-2003
This paper is concerned with the extent to which both structural and agency factors were at play in the establishment and maintenance of an innovative model of Education Studies at Murdoch University in Western Australia, from the mid 1970s to 2003. Regarding structural factors, the fact that the University was established as one of a number of ‘new’ universities on the national scene, with a brief to break out of the curricular traditions of the established universities, meant that there was latitude for the adoption of new curriculum structures in outlining the parameters of Education Studies. However, it required the agency of Brian Hill, the Foundation Professor of Education, to make this happen. The paper outlines how the nature of the model that eventuated was largely a transfer of models which Hill witnessed both in North America and within Australia and which he adapted to local conditions, seeking in the process to bring about what he considered to be an improved composite version based on his professional experience in a number of universities
Blockchain vehicles for efficient Medical Record management
The lack of interoperability in Britain’s medical records systems precludes the realisation of benefits generated by increased spending elsewhere in healthcare. Growing concerns regarding the security of online medical data following breaches, and regarding regulations governing data ownership, mandate strict parameters in the development of efficient methods to administrate medical records. Furthermore, consideration must be placed on the rise of connected devices, which vastly increase the amount of data that can be collected in order to improve a patient’s long-term health outcomes. Increasing numbers of healthcare systems are developing Blockchain-based systems to manage medical data. A Blockchain is a decentralised, continuously growing online ledger of records, validated by members of the network. Traditionally used to manage cryptocurrency records, distributed ledger technology can be applied to various aspects of healthcare. In this manuscript, we focus on how Electronic Medical Records in particular can be managed by Blockchain, and how the introduction of this novel technology can create a more efficient and interoperable infrastructure to manage records that leads to improved healthcare outcomes, while maintaining patient data ownership and without compromising privacy or security of sensitive data
Persistence in Cluster--Cluster Aggregation
Persistence is considered in diffusion--limited cluster--cluster aggregation,
in one dimension and when the diffusion coefficient of a cluster depends on its
size as . The empty and filled site persistences are
defined as the probabilities, that a site has been either empty or covered by a
cluster all the time whereas the cluster persistence gives the probability of a
cluster to remain intact. The filled site one is nonuniversal. The empty site
and cluster persistences are found to be universal, as supported by analytical
arguments and simulations. The empty site case decays algebraically with the
exponent . The cluster persistence is related to the
small behavior of the cluster size distribution and behaves also
algebraically for while for the behavior is
stretched exponential. In the scaling limit and with fixed the distribution of intervals of size between
persistent regions scales as , where is the average interval size and . For finite the
scaling is poor for , due to the insufficient separation of the two
length scales: the distances between clusters, , and that between
persistent regions, . For the size distribution of persistent regions
the time and size dependences separate, the latter being independent of the
diffusion exponent but depending on the initial cluster size
distribution.Comment: 14 pages, 12 figures, RevTeX, submitted to Phys. Rev.
Mode Identification from Combination Frequency Amplitudes in ZZ Ceti Stars
The lightcurves of variable DA stars are usually multi-periodic and
non-sinusoidal, so that their Fourier transforms show peaks at eigenfrequencies
of the pulsation modes and at sums and differences of these frequencies. These
combination frequencies provide extra information about the pulsations, both
physical and geometrical, that is lost unless they are analyzed. Several
theories provide a context for this analysis by predicting combination
frequency amplitudes. In these theories, the combination frequencies arise from
nonlinear mixing of oscillation modes in the outer layers of the white dwarf,
so their analysis cannot yield direct information on the global structure of
the star as eigenmodes provide. However, their sensitivity to mode geometry
does make them a useful tool for identifying the spherical degree of the modes
that mix to produce them. In this paper, we analyze data from eight hot,
low-amplitude DAV white dwarfs and measure the amplitudes of combination
frequencies present. By comparing these amplitudes to the predictions of the
theory of Goldreich & Wu, we have verified that the theory is crudely
consistent with the measurements. We have also investigated to what extent the
combination frequencies can be used to measure the spherical degree (ell) of
the modes that produce them. We find that modes with ell > 2 are easily
identifiable as high ell based on their combination frequencies alone.
Distinguishing between ell=1 and 2 is also possible using harmonics. These
results will be useful for conducting seismological analysis of large ensembles
of ZZ Ceti stars, such as those being discovered using the Sloan Digital Sky
Survey. Because this method relies only on photometry at optical wavelengths,
it can be applied to faint stars using 4 m class telescopes.Comment: 73 pages, 22 figures, accepted in the Ap
Investing in Prevention or Paying for Recovery - Attitudes to Cyber Risk
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Broadly speaking an individual can invest time and effort to avoid becoming victim to a cyber attack and/or they can invest resource in recovering from any attack. We introduce a new game called the pre-vention and recovery game to study this trade-off. We report results from the experimental lab that allow us to categorize different approaches to risk taking. We show that many individuals appear relatively risk loving in that they invest in recovery rather than prevention. We find little difference in behavior between a gain and loss framing
Possible detection of two giant extrasolar planets orbiting the eclipsing polar UZ Fornacis
We present new high-speed, multi-observatory, multi-instrument photometry of
the eclipsing polar UZ For in order to measure precise mid-eclipse times with
the aim of detecting any orbital period variations. When combined with
published eclipse times and archival data spanning ~27 years, we detect
departures from a linear and quadratic trend of ~60 s. The departures are
strongly suggestive of two cyclic variations of 16(3) and 5.25(25) years. The
two favoured mechanisms to drive the periodicities are either two giant
extrasolar planets as companions to the binary (with minimum masses of
6.3(1.5)M(Jupiter) and 7.7(1.2)M(Jupiter)) or a magnetic cycle mechanism (e.g.
Applegate's mechanism) of the secondary star. Applegate's mechanism would
require the entire radiant energy output of the secondary and would therefore
seem to be the least likely of the two, barring any further refinements in the
effect of magnetic fieilds (e.g. those of Lanza et al.). The two planet model
can provide realistic solutions but it does not quite capture all of the
eclipse times measurements. A highly eccentric orbit for the outer planet would
fit the data nicely, but we find that such a solution would be unstable. It is
also possible that the periodicities are driven by some combination of both
mechanisms. Further observations of this system are encouraged.Comment: 10 pages, 4 figures, 2 table
Cluster persistence in one-dimensional diffusion--limited cluster--cluster aggregation
The persistence probability, , of a cluster to remain unaggregated is
studied in cluster-cluster aggregation, when the diffusion coefficient of a
cluster depends on its size as . In the mean-field the
problem maps to the survival of three annihilating random walkers with
time-dependent noise correlations. For the motion of persistent
clusters becomes asymptotically irrelevant and the mean-field theory provides a
correct description. For the spatial fluctuations remain relevant
and the persistence probability is overestimated by the random walk theory. The
decay of persistence determines the small size tail of the cluster size
distribution. For the distribution is flat and, surprisingly,
independent of .Comment: 11 pages, 6 figures, RevTeX4, submitted to Phys. Rev.
High Resolution Spectroscopy of the Pulsating White Dwarf G29-38
We present the analysis of time-resolved, high resolution spectra of the cool
white dwarf pulsator, G29-38. From measuring the Doppler shifts of the H-alpha
core, we detect velocity changes as large as 16.5 km/s and conclude that they
are due to the horizontal motions associated with the g-mode pulsations on the
star. We detect seven pulsation modes from the velocity time-series and
identify the same modes in the flux variations. We discuss the properties of
these modes and use the advantage of having both velocity and flux measurements
of the pulsations to test the convective driving theory proposed for DAV stars.
Our data show limited agreement with the expected relationships between the
amplitude and phases of the velocity and flux modes. Unexpectedly, the velocity
curve shows evidence for harmonic distortion, in the form of a peak in the
Fourier transform whose frequency is the exact sum of the two largest
frequencies. Combination frequencies are a characteristic feature of the
Fourier transforms of light curves of G29-38, but before now have not been
detected in the velocities, nor does published theory predict that they should
exist. We compare our velocity combination frequency to combination frequencies
found in the analysis of light curves of G29-38, and discuss what might account
for the existence of velocity combinations with the properties we observe.
We also use our high-resolution spectra to determine if either rotation or
pulsation can explain the truncated shape observed for the DAV star's line
core. We are able to eliminate both mechanisms: the average spectrum does not
fit the rotationally broadened model and the time-series of spectra provides
proof that the pulsations do not significantly truncate the line.Comment: 24 pages, 9 figures, Accepted for publication in ApJ (June
Ensemble Characteristics of the ZZ Ceti stars
We present the observed pulsation spectra of all known non-interacting ZZ
Ceti stars (hydrogen atmosphere white dwarf variables; DAVs) and examine
changes in their pulsation properties across the instability strip. We confirm
the well established trend of increasing pulsation period with decreasing
effective temperature across the ZZ Ceti instability strip. We do not find a
dramatic order of magnitude increase in the number of observed independent
modes in ZZ Ceti stars, traversing from the hot to the cool edge of the
instability strip; we find that the cool DAVs have one more mode on average
compared to the hot DAVs. We confirm the initial increase in pulsation
amplitude at the blue edge, and find strong evidence of a decline in amplitude
prior to the red edge. We present the first observational evidence that ZZ Ceti
stars lose pulsation energy just before pulsations shut down at the empirical
red edge of the instability strip.Comment: ApJ, in press. (26 pages, 3 figures
Prevalence of chronic kidney disease in adults in England: comparison of nationally representative cross-sectional surveys from 2003 to 2016
Objectives: To identify recent trends in chronic kidney disease (CKD) prevalence in England and explore their association with changes in sociodemographic, behavioural and clinical factors. Design: Pooled cross-sectional analysis.Setting: Health Survey for England 2003, 2009/2010 combined, and 2016.Participants: 17,663 individuals (aged 16+) living in private households.Primary and secondary outcome measures: Prevalence of estimated glomerular filtration rate (eGFR
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