4,032 research outputs found
Play it Again: Evolved Audio Effects and Synthesizer Programming
Automatic programming of sound synthesizers and audio devices to match a given, desired sound is examined and a Genetic Algorithm (GA) that functions independent of specific synthesis techniques is proposed. Most work in this area has focused on one synthesis model or synthesizer, designing the GA and tuning the operator parameters to obtain optimal results. The scope of such inquiries has been limited by available computing power, however current software (Ableton Live, herein) and commercially available hardware is shown to quickly find accurate solutions, promising a practical application for music creators. Both software synthesizers and audio effects processors are examined, showing a wide range of performance times (from seconds to hours) and solution accuracy, based on particularities of the target devices. Random oscillators, phase synchronizing, and filters over empty frequency ranges are identified as primary challenges for GA based optimization
The WARPS survey - IV: The X-ray luminosity-temperature relation of high redshift galaxy clusters
We present a measurement of the cluster X-ray luminosity-temperature relation
out to high redshift (z~0.8). Combined ROSAT PSPC spectra of 91 galaxy clusters
detected in the Wide Angle ROSAT Pointed Survey (WARPS) are simultaneously fit
in redshift and luminosity bins. The resulting temperature and luminosity
measurements of these bins, which occupy a region of the high redshift L-T
relation not previously sampled, are compared to existing measurements at low
redshift in order to constrain the evolution of the L-T relation. We find a
best fit to low redshift (z1 keV, to be L proportional
to T^(3.15\pm0.06). Our data are consistent with no evolution in the
normalisation of the L-T relation up to z~0.8. Combining our results with ASCA
measurements taken from the literature, we find eta=0.19\pm0.38 (for Omega_0=1,
with 1 sigma errors) where L_Bol is proportional to (1 + z)^eta T^3.15, or
eta=0.60\pm0.38 for Omega_0=0.3. This lack of evolution is considered in terms
of the entropy-driven evolution of clusters. Further implications for
cosmological constraints are also discussed.Comment: 11 pages, 7 figures, accepted for publication in MNRA
Winds of Planet Hosting Stars
The field of exoplanetary science is one of the most rapidly growing areas of
astrophysical research. As more planets are discovered around other stars, new
techniques have been developed that have allowed astronomers to begin to
characterise them. Two of the most important factors in understanding the
evolution of these planets, and potentially determining whether they are
habitable, are the behaviour of the winds of the host star and the way in which
they interact with the planet. The purpose of this project is to reconstruct
the magnetic fields of planet hosting stars from spectropolarimetric
observations, and to use these magnetic field maps to inform simulations of the
stellar winds in those systems using the Block Adaptive Tree Solar-wind Roe
Upwind Scheme (BATS-R-US) code. The BATS-R-US code was originally written to
investigate the behaviour of the Solar wind, and so has been altered to be used
in the context of other stellar systems. These simulations will give
information about the velocity, pressure and density of the wind outward from
the host star. They will also allow us to determine what influence the winds
will have on the space weather environment of the planet. This paper presents
the preliminary results of these simulations for the star Bo\"otis,
using a newly reconstructed magnetic field map based on previously published
observations. These simulations show interesting structures in the wind
velocity around the star, consistent with the complex topology of its magnetic
field.Comment: 8 pages, 2 figures, accepted for publication in the peer-reviewed
proceedings of the 14th Australian Space Research Conference, held at the
University of South Australia, 29th September - 1st October 201
Finite size scaling in neural networks
We demonstrate that the fraction of pattern sets that can be stored in
single- and hidden-layer perceptrons exhibits finite size scaling. This feature
allows to estimate the critical storage capacity \alpha_c from simulations of
relatively small systems. We illustrate this approach by determining \alpha_c,
together with the finite size scaling exponent \nu, for storing Gaussian
patterns in committee and parity machines with binary couplings and up to K=5
hidden units.Comment: 4 pages, RevTex, 5 figures, uses multicol.sty and psfig.st
Reply to Morel : cadmium as a micronutrient and macrotoxin in the oceans
Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of National Academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences of the United States of America 110 (2013): E1878, doi:10.1073/pnas.1305068110.We thank François Morel for his interest in our study. Morel states that our conclusions are based on
the approximate match between the Cd-isotope composition of cultured bacteria and the fractionation
of Cd isotopes seen in seawater (1). This match is only a minor component of our argument, and we
welcome the opportunity to reiterate our case
Developing and testing a strategy to enhance a palliative approach and care continuity for people who have dementia: Study overview and protocol
Background: Typically, dementia involves progressive cognitive and functional deterioration, leading to death. A palliative approach recognizes the inevitable health decline, focusing on quality of life. The approach is holistic, proactive, supports the client and the family, and can be provided by the client’s usual care team.
In the last months of life, distressing symptoms, support needs, and care transitions may escalate. This project trialed a strategy intended to support a consistent, high quality, palliative approach for people with dementia drawing close to death. The strategy was to implement two communities of practice, drawn primarily from service provider organizations across care sectors, supporting them to address practice change. Communities comprised practitioners and other health professionals with a passionate commitment to dementia palliative care and the capacity to drive practice enhancement within partnering organizations.
Project aims were to document: (i) changes driven by the communities of practice; (ii) changes in staff/practitioner characteristics during the study (knowledge of a palliative approach and dementia; confidence delivering palliative care; views on death and dying, palliative care, and a palliative approach for dementia); (iii) outcomes from perspectives of family carers, care providers, and community of practice members; (iv) the extent to which changes enhanced practice and care continuity; and (v) barriers to and facilitators of successful community of practice implementation.
Methods/design: This action research project was implemented over 14 months in 2010/11 in metropolitan Perth, Western Australia and regional Launceston, Tasmania. Each state based community of practice worked with the researchers to scope existing practice and its outcomes. The research team compiled a report of existing practice recommendations and resources. Findings of these two steps informed community of practice action plans and development of additional resources. Change implementation was recorded and explored in interviews, comparisons being made with practice recommendations. Changes in staff/practitioner characteristics were evaluated using survey data. Findings from semi structured interviews and survey administration established outcomes from perspectives of family carers, care providers, and community of practice members. Consideration of processes and outcomes, across the two state based settings, informed identification of barriers and facilitators. Community of practice reflections also informed study recommendations
Intermediate Element Abundances in Galaxy Clusters
We present the average abundances of the intermediate elements obtained by
performing a stacked analysis of all the galaxy clusters in the archive of the
X-ray telescope ASCA. We determine the abundances of Fe, Si, S, and Ni as a
function of cluster temperature (mass) from 1--10 keV, and place strong upper
limits on the abundances of Ca and Ar. In general, Si and Ni are overabundant
with respect to Fe, while Ar and Ca are very underabundant. The discrepancy
between the abundances of Si, S, Ar, and Ca indicate that the alpha-elements do
not behave homogeneously as a single group. We show that the abundances of the
most well-determined elements Fe, Si, and S in conjunction with recent
theoretical supernovae yields do not give a consistent solution for the
fraction of material produced by Type Ia and Type II supernovae at any
temperature or mass. The general trend is for higher temperature clusters to
have more of their metals produced in Type II supernovae than in Type Ias. The
inconsistency of our results with abundances in the Milky Way indicate that
spiral galaxies are not the dominant metal contributors to the intracluster
medium (ICM). The pattern of elemental abundances requires an additional source
of metals beyond standard SNIa and SNII enrichment. The properties of this new
source are well matched to those of Type II supernovae with very massive,
metal-poor progenitor stars. These results are consistent with a significant
fraction of the ICM metals produced by an early generation of population III
stars.Comment: 18 pages, 11 figures, 7 tables. Submitted to Ap
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