1,000 research outputs found
A MERLIN Observation of PSR B1951+32 and its associated Plerion
In an investigative 16 hour L band observation using the MERLIN radio
interferometric array, we have resolved both the pulsar PSR B1951+32 and
structure within the flat spectral radio continuum region, believed to be the
synchrotron nebula associated with the interaction of the pulsar and its `host'
supernova remnant CTB 80. The extended structure we see, significant at
4.5 , is of dimensions 2.5" 0.75", and suggests a sharp bow
shaped arc of shocked emission, which is correlated with similar structure
observed in lower resolution radio maps and X-ray images. Using this MERLIN
data as a new astrometric reference for other multiwavelength data we can place
the pulsar at one edge of the HST reported optical synchrotron knot, ruling out
previous suggested optical counterparts, and allowing an elementary analysis of
the optical synchrotron emission which appears to trail the pulsar. The latter
is possibly a consequence of pulsar wind replenishment, and we suggest that the
knot is a result of magnetohydrodynamic (MHD) instabilities. These being so, it
suggests a dynamical nature to the optical knot, which will require high
resolution optical observations to confirm.Comment: 12 pages, 2 figures. Accepted for publication in ApJ
Coordinating government and community support for community language teaching in Australia: Overview with special attention to New South Wales
An overview of formal government language-in-education planning for community languages (CLs) that has been undertaken in Australia and New South Wales is provided, moving from the more informal programmes provided in the 1980s to school-oriented programmes and training at the turn of the century. These programmes depend on community support; for many of the teachers from the communities, methodological training is needed to complement their language and cultural skills. At the same time, Commonwealth (Federal) and State support for CL programmes has improved their quality and provides students with opportunities to study CLs at the senior secondary matriculation level. The paper concludes with specific recommendations for greater recognition of CL schools and for greater attention to CL teacher preparation
Contribution of extracellular negatively charged residues to ATP action and zinc modulation of rat P2X 2 receptors
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65506/1/j.1471-4159.2008.05228.x.pd
Magnetohydrodynamic activity inside a sphere
We present a computational method to solve the magnetohydrodynamic equations
in spherical geometry. The technique is fully nonlinear and wholly spectral,
and uses an expansion basis that is adapted to the geometry:
Chandrasekhar-Kendall vector eigenfunctions of the curl. The resulting lower
spatial resolution is somewhat offset by being able to build all the boundary
conditions into each of the orthogonal expansion functions and by the
disappearance of any difficulties caused by singularities at the center of the
sphere. The results reported here are for mechanically and magnetically
isolated spheres, although different boundary conditions could be studied by
adapting the same method. The intent is to be able to study the nonlinear
dynamical evolution of those aspects that are peculiar to the spherical
geometry at only moderate Reynolds numbers. The code is parallelized, and will
preserve to high accuracy the ideal magnetohydrodynamic (MHD) invariants of the
system (global energy, magnetic helicity, cross helicity). Examples of results
for selective decay and mechanically-driven dynamo simulations are discussed.
In the dynamo cases, spontaneous flips of the dipole orientation are observed.Comment: 15 pages, 19 figures. Improved figures, in press in Physics of Fluid
Hydrodynamic and magnetohydrodynamic computations inside a rotating sphere
Numerical solutions of the incompressible magnetohydrodynamic (MHD) equations
are reported for the interior of a rotating, perfectly-conducting, rigid
spherical shell that is insulator-coated on the inside. A previously-reported
spectral method is used which relies on a Galerkin expansion in
Chandrasekhar-Kendall vector eigenfunctions of the curl. The new ingredient in
this set of computations is the rigid rotation of the sphere. After a few
purely hydrodynamic examples are sampled (spin down, Ekman pumping, inertial
waves), attention is focused on selective decay and the MHD dynamo problem. In
dynamo runs, prescribed mechanical forcing excites a persistent velocity field,
usually turbulent at modest Reynolds numbers, which in turn amplifies a small
seed magnetic field that is introduced. A wide variety of dynamo activity is
observed, all at unit magnetic Prandtl number. The code lacks the resolution to
probe high Reynolds numbers, but nevertheless interesting dynamo regimes turn
out to be plentiful in those parts of parameter space in which the code is
accurate. The key control parameters seem to be mechanical and magnetic
Reynolds numbers, the Rossby and Ekman numbers (which in our computations are
varied mostly by varying the rate of rotation of the sphere) and the amount of
mechanical helicity injected. Magnetic energy levels and magnetic dipole
behavior are exhibited which fluctuate strongly on a time scale of a few eddy
turnover times. These seem to stabilize as the rotation rate is increased until
the limit of the code resolution is reached.Comment: 26 pages, 17 figures, submitted to New Journal of Physic
The effect of prior deformation on the foaming behavior of 'FORMGRIP' precursor material
It is shown that extrusion of "FORMGRIP" precursor material prior to baking leads to accelerated foaming and finer, more uniform cell structures. This effect is correlated with microstructural observations made on the precursor materials and on the foams, It is thought that, while extrusion apparently does not extensively fracture the gas-generating hydride particles, it does induce sonic damage to their protective surface oxide layers. Removal of the porosity normally present in as-cast precursors may also be beneficial
Relationship between solidification microstructure and hot cracking susceptibility for continuous casting of low-carbon and high-strength low-alloyed steels: A phase-field study
© The Minerals, Metals & Materials Society and ASM International 2013Hot cracking is one of the major defects in continuous casting of steels, frequently limiting the productivity. To understand the factors leading to this defect, microstructure formation is simulated for a low-carbon and two high-strength low-alloyed steels. 2D simulation of the initial stage of solidification is performed in a moving slice of the slab using proprietary multiphase-field software and taking into account all elements which are expected to have a relevant effect on the mechanical properties and structure formation during solidification. To account for the correct thermodynamic and kinetic properties of the multicomponent alloy grades, the simulation software is online coupled to commercial thermodynamic and mobility databases. A moving-frame boundary condition allows traveling through the entire solidification history starting from the slab surface, and tracking the morphology changes during growth of the shell. From the simulation results, significant microstructure differences between the steel grades are quantitatively evaluated and correlated with their hot cracking behavior according to the Rappaz-Drezet-Gremaud (RDG) hot cracking criterion. The possible role of the microalloying elements in hot cracking, in particular of traces of Ti, is analyzed. With the assumption that TiN precipitates trigger coalescence of the primary dendrites, quantitative evaluation of the critical strain rates leads to a full agreement with the observed hot cracking behavior. © 2013 The Minerals, Metals & Materials Society and ASM International
Medicines adherence: Involving patients in decisions about prescribed medicines and supporting adherence
It is thought that between a third and a half of all medicines1
There are many causes of non-adherence but they fall into two overlapping categories: intentional and unintentional. Unintentional non-adherence occurs when the patient wants to follow the agreed treatment but is prevented from doing so by barriers that are beyond their control. Examples include poor recall or difficulties in understanding the instructions, problems with using the treatment, inability to pay for the treatment, or simply forgetting to take it. prescribed for long-term conditions are not taken as recommended. If the prescription is appropriate, then this may represent a loss to patients, the healthcare system and society. The costs are both personal and economic. Adherence presumes an agreement between prescriber and patient about the prescriberâs recommendations. Adherence to medicines is defined as the extent to which the patientâs action matches the agreed recommendations. Non-adherence may limit the benefits of medicines, resulting in lack of improvement, or deterioration, in health. The economic costs are not limited to wasted medicines but also include the knock-on costs arising from increased demands for healthcare if health deteriorates. Non-adherence should not be seen as the patientâs problem. It represents a fundamental limitation in the delivery of healthcare, often because of a failure to fully agree the prescription in the first place or to identify and provide the support that patients need later on. Addressing non-adherence is not about getting patients to take more medicines per se. Rather, it starts with an exploration of patientsâ perspectives of medicines and the reasons why they may not want or are unable to use them. Healthcare professionals have a duty to help patients make informed decisions about treatment and use appropriately prescribed medicines to best effec
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