830 research outputs found
Counter-conditioning as an intervention to modify anti-fat attitudes
This study examined the effect of anti-fat attitude counter-conditioning using positive images of obese individuals participants completed implicit and explicit measures of attitudes towards fatness on three occasions: no intervention; following exposure to positive images of obese members of the general public; and to images of obese celebrities. Contrary to expectations, positive images of obese individuals did not result in more positive attitudes towards fatness as expected and, in some cases, indices of these attitudes worsened. Results suggest that attitudes towards obesity and fatness may be somewhat robust and resistant to change, possibly suggesting a central and not peripheral processing route for their formation
Aspects of the geochemistry of Onverwacht Group lavas from the Barberton Greenstone Belt
Bibliography: pages 225-253.The 3540 million year old komatiitic and tholeiitic lavas in the Onverwacht Group (Barberton greenstone belt) crop out in the rugged terrain of the eastern Transvaal lowveld. The results of an investigation into the geochemistry of the lavas, mainly from the three lower Formations of the Onverwacht Group - the Lower Ultramafic Unit (LUU) - are reported. While the lavas generally show excellent textural preservation, their primary phases have usually been reconstituted to greenschist facies mineral assemblages. Although original phenocryst phases are often pseudomorphed, they can still be identified from occasionally preserved relict grains and from the secondary mineral assemblages. In this way all the major phases that occur in the various lava types could be identified. However, before the geochemical data could be used to examine the effects of partial melting and/or crystal fractionation processes in the development of the magma compositions, it was necessary to investigate which elements had been redistributed by later metamorphic and other alteration events that have occurred in the history of the lavas
Generalised action-angle coordinates defined on island chains
Straight-field-line coordinates are very useful for representing magnetic
fields in toroidally confined plasmas, but fundamental problems arise regarding
their definition in 3-D geometries because of the formation of islands and
chaotic field regions, ie non-integrability. In Hamiltonian dynamical systems
terms these coordinates are a form of action-angle variables, which are
normally defined only for integrable systems. In order to describe 3-D magnetic
field systems, a generalisation of this concept was proposed recently by the
present authors that unified the concepts of ghost surfaces and
quadratic-flux-minimising (QFMin) surfaces. This was based on a simple
canonical transformation generated by a change of variable , where and are poloidal and toroidal
angles, respectively, with a new poloidal angle chosen to give
pseudo-orbits that are a) straight when plotted in the plane and
b) QFMin pseudo-orbits in the transformed coordinate. These two requirements
ensure that the pseudo-orbits are also c) ghost pseudo-orbits. In the present
paper, it is demonstrated that these requirements do not \emph{uniquely}
specify the transformation owing to a relabelling symmetry. A variational
method of solution that removes this lack of uniqueness is proposed.Comment: 10 pages. Accepted by Plasma Physics and Controlled Fusion as part of
a cluster of refereed papers in a special issue containing papers arising
from the Joint International Stellarator & Heliotron Workshop and
Asia-Pacific Plasma Theory Conference, held in Canberra and Murramarang
Resort, Australia, 30 January - 3 February, 201
Relaxed plasma equilibria and entropy-related plasma self-organization principles
The concept of plasma relaxation as a constrained energy minimization is reviewed. Recent work by the authors on generalizing this approach to partially relaxed threedimensional plasma systems in a way consistent with chaos theory is discussed, with a view to clarifying the thermodynamic aspects of the variational approach used. Other entropy-related approaches to finding long-time steady states of turbulent or chaotic plasma systems are also briefly reviewed
Multi-region relaxed magnetohydrodynamics with anisotropy and flow
We present an extension of the multi-region relaxed magnetohydrodynamics
(MRxMHD) equilibrium model that includes pressure anisotropy and general plasma
flows. This anisotropic extension to our previous isotropic model is motivated
by Sun and Finn's model of relaxed anisotropic magnetohydrodynamic equilibria.
We prove that as the number of plasma regions becomes infinite, our anisotropic
extension of MRxMHD reduces to anisotropic ideal MHD with flow. The
continuously nested flux surface limit of our MRxMHD model is the first
variational principle for anisotropic plasma equilibria with general flow
fields.Comment: 11 pages, 2 figures. arXiv admin note: text overlap with
arXiv:1401.307
An efficient method for the anisotropic diffusion equation in magnetic fields
We solve the anisotropic diffusion equation in 2D, where the dominant
direction of diffusion is defined by a vector field which does not conform to a
Cartesian grid. Our method uses operator splitting to separate the diffusion
perpendicular and parallel to the vector field. The slow time scale is solved
using a provably stable finite difference formulation in the perpendicular to
the vector field, and an integral operator for the diffusion parallel to it.
Energy estimates are shown to for the continuous and semi-discrete cases.
Numerical experiments are performed showing convergence of the method, and
examples is given to demonstrate the capabilities of the method
Provably stable numerical method for the anisotropic diffusion equation in toroidally confined magnetic fields
We present a novel numerical method for solving the anisotropic diffusion
equation in toroidally confined magnetic fields which is efficient, accurate
and provably stable. The continuous problem is written in terms of a derivative
operator for the perpendicular transport and a linear operator, obtained
through field line tracing, for the parallel transport. We derive energy
estimates of the solution of the continuous initial boundary value problem. A
discrete formulation is presented using operator splitting in time with the
summation by parts finite difference approximation of spatial derivatives for
the perpendicular diffusion operator. Weak penalty procedures are derived for
implementing both boundary conditions and parallel diffusion operator obtained
by field line tracing. We prove that the fully-discrete approximation is
unconditionally stable and asymptotic preserving. Discrete energy estimates are
shown to match the continuous energy estimate given the correct choice of
penalty parameters. Convergence tests are shown for the perpendicular operator
by itself, and the ``NIMROD benchmark" problem is used as a manufactured
solution to show the full scheme converges even in the case where the
perpendicular diffusion is zero. Finally, we present a magnetic field with
chaotic regions and islands and show the contours of the anisotropic diffusion
equation reproduce key features in the field.Comment: 33 pages, 8 figure
The dynamics of collaborative resistance: negotiating the methodological incongruities of art, cultural theory, science and design.
This paper reflectively explores how the collaborative team behind in potēntia critically and creatively embraces the methodological dialectics that occur when trying to accommodate the different disciplinary approaches of art, cultural theory, science and design. Hosted by SymbioticA - The Centre of Excellence in the Biological Arts, The University of Western Australia, in potēntia is an example of multi-disciplinary collaborative art/science practice pioneered by SymbioticA. Negotiating aesthetics versus accuracy, risk versus rigor, experimentation versus speculation, and problematising versus problem solving, this paper reflexively discusses how cross-disciplinary collaboration, although fraught with friction also presents new and unique opportunities - professionally and personally - for unexpected creative discoveries to emerge
- …