Particle simulation of plasmas on the massively parallel processor

Particle simulations, in which collective phenomena in plasmas are studied by following the self consistent motions of many discrete particles, involve several highly repetitive sets of calculations that are readily adaptable to SIMD parallel processing. A fully electromagnetic, relativistic plasma simulation for the massively parallel processor is described. The particle motions are followed in 2 1/2 dimensions on a 128 x 128 grid, with periodic boundary conditions. The two dimensional simulation space is mapped directly onto the processor network; a Fast Fourier Transform is used to solve the field equations. Particle data are stored according to an Eulerian scheme, i.e., the information associated with each particle is moved from one local memory to another as the particle moves across the spatial grid. The method is applied to the study of the nonlinear development of the whistler instability in a magnetospheric plasma model, with an anisotropic electron temperature. The wave distribution function is included as a new diagnostic to allow simulation results to be compared with satellite observations

Bistability in a simple fluid network due to viscosity contrast

We study the existence of multiple equilibrium states in a simple fluid network using Newtonian fluids and laminar flow. We demonstrate theoretically the presence of hysteresis and bistability, and we confirm these predictions in an experiment using two miscible fluids of different viscosity--sucrose solution and water. Possible applications include bloodflow, microfluidics, and other network flows governed by similar principles

PILOT: design and capabilities

The proposed design for PILOT is a general-purpose, wide-field 1 degree 2.4m, f/10 Ritchey-Chretien telescope, with fast tip-tilt guiding, for use 0.5-25 microns. The design allows both wide-field and diffraction-limited use at these wavelengths. The expected overall image quality, including median seeing, is 0.28-0.3" FWHM from 0.8-2.4 microns. Point source sensitivities are estimated.Comment: 4 pages, Proceedings of 2nd ARENA conference 'The Astrophysical Science Cases at Dome C', Potsdam, 17-21 September 200

Crystal structures of four indole derivatives as possible cannabinoid allosteric antagonists

Acknowledgements We thank the EPSRC National Crystallography Service (University of Southampton) for the data collections and the EPSRC National Mass Spectrometry Service (University of Swansea) for the HRMS data. We thank John Low for carrying out the Cambridge Database survey.Peer reviewedPublisher PD

Radiative recombination data for modeling dynamic finite-density plasmas

We have calculated partial final-state resolved radiative recombination (RR) rate coefficients from the initial ground and metastable levels of all elements up to and including Zn, plus Kr, Mo, and Xe, for all isoelectronic sequences up to Na-like forming Mg-like. The data are archived according to the Atomic Data and Analysis Structure (ADAS) data class adf48, which spans a temperature range of z2(101-107) K, where z is the initial ion charge. Fits to total rate coefficients have been determined, for both the ground and metastable levels, and those for the ground are presented here. Comparison is made both with previous RR rate coefficients and with (background) R-matrix photoionization cross sections. This RR database complements a dielectronic recombination (DR) database already produced, and both are being used to produce updated ionization balances for both (electron) collisionally ionized and photoionized plasmas

X-ray enabled MOCASSIN: a 3D code for photoionized media

We present a new version of the fully 3D photoionization and dust radiative transfer code, MOCASSIN, that uses a Monte Carlo approach for the transfer of radiation. The X-ray enabled MOCASSIN allows a fully geometry independent description of low-density gaseous environments strongly photoionized by a radiation field extending from radio to gamma rays. The code has been thoroughly benchmarked against other established codes routinely used in the literature, using simple plane parallel models designed to test performance under standard conditions. We show the results of our benchmarking exercise and discuss applicability and limitations of the new code, which should be of guidance for future astrophysical studies with MOCASSIN.Comment: Accepted for publication in ApJS 9 pages, 5 figure

Territorial Tactics: The Socio-spatial Significance of Private Policing Strategies in Cape Town

This paper analyses the policing strategies of private security companies operating in urban space. An existing literature has considered the variety of ways that territory becomes of fundamental importance in the work of public police forces. However, this paper examines territory in the context of private security companies. Drawing on empirical research in Cape Town, it examines how demarcated territories become key subjects in private policing. Private security companies are responsible for a relatively small section of the city, while in contrast the public police ultimately have to see city space as a whole. Hence, private policing strategy becomes one of displacement, especially of so-called undesirables yielding a patchworked public space associated with private enclaves of consumption. The conclusions signal the historical resonances and comparative implications of these political-legal-security dynamics. © 2013 Urban Studies Journal Limited

Tau Aggregation Inhibitor Therapy : An Exploratory Phase 2 Study in Mild or Moderate Alzheimer's Disease

ACKNOWLEDGMENTS We thank patients and their caregivers for their participation in the study and are indebted to all the investigators involved in the study, particularly Drs. Douglas Fowlie and Donald Mowat for their helpful contributions to the clinical execution of the study in Scotland. We thank Sharon Eastwood, Parexel, for assistance in preparing initial drafts of the manuscript. We acknowledge constructive comments provided by Professors G. Wilcock and S. Gauthier on drafts of the article. CMW, CRH, and JMDS are officers of, and hold beneficial interests in, TauRx Therapeutics. RTS, PB, KK, and DJW are paid consultants to TauRx Therapeutics. The study was financed entirely by TauRx TherapeuticsPeer reviewedPublisher PD