75,986 research outputs found
The RHMC Algorithm for 2 Flavours of Dynamical Staggered Fermions
We describe an implementation of the Rational Hybrid Monte Carlo (RHMC)
algorithm for dynamical computations with two flavours of staggered quarks. We
discuss several variants of the method, the performance and possible sources of
error for each of them, and we compare the performance and results to the
inexact R algorithm.Comment: Lattice2003(machine) 3 pages, 1 figure. Added referenc
On the Holomorphic Structure of a Low Energy Supersymmetric Wilson Effective Action
The Wilson (exact) renormalization group equations are used to determine the
evolution of a general low energy N=1 supersymmetric action containing a U(1)
gauge vector multiplet and a neutral chiral multiplet. The effective theory
evolves towards satisfying a fixed relation where the K\"ahler potential and
effective gauge coupling are obtained from a N=2 supersymmetric holomorphic
prepotential.Comment: 10 pages, LaTe
The Accountability and Independence of the Auditors-General of Australia: A Comparison of their Enabling Legislation
This paper compares the enabling legislation of the nine auditors-general of Australia from perspectives of public-sector accountability and auditor independence. Following on from the Joint Committee of Public Accounts (JCPA) 1989 and 1996 reports, and in particular English and Guthrie (2000), this study finds general similarities in the enabling legislation for all auditors-general, and striking similarities between the legislation of the commonwealth and Victoria. The policy implications of this study's findings are that for all auditors-general provisions in their enabling legislation could be further strengthened
Finding flows in the one-way measurement model
The one-way measurement model is a framework for universal quantum
computation, in which algorithms are partially described by a graph G of
entanglement relations on a collection of qubits. A sufficient condition for an
algorithm to perform a unitary embedding between two Hilbert spaces is for the
graph G, together with input/output vertices I, O \subset V(G), to have a flow
in the sense introduced by Danos and Kashefi [quant-ph/0506062]. For the
special case of |I| = |O|, using a graph-theoretic characterization, I show
that such flows are unique when they exist. This leads to an efficient
algorithm for finding flows, by a reduction to solved problems in graph theory.Comment: 8 pages, 3 figures: somewhat condensed and updated version, to appear
in PR
IRAS 18357-0604 – an analogue of the galactic yellow hypergiant IRC +10420?
Context. Yellow hypergiants represent a short-lived evolutionary episode experienced by massive stars as they transit to and from a red supergiant phase. As such, their properties provide a critical test of stellar evolutionary theory, while recent observations unexpectedly suggest that a subset may explode as Type II supernovae.Aims. The galactic yellow hypergiant IRC +10420 is a cornerstone system for understanding this phase since it is the strongest post-RSG candidate known, has demonstrated real-time evolution across the Hertzsprung-Russell diagram and been subject to extensive mass loss. In this paper we report on the discovery of a twin of IRC +10420 - IRAS 18357-0604.Methods. Optical and near-IR spectroscopy are used to investigate the physical properties of IRAS 18357-0604 and also provide an estimate of its systemic velocity, while near- to mid-IR photometry probes the nature of its circumstellar environment.Results. These observations reveal pronounced spectral similarities between IRAS 18357-0604 and IRC +10420, suggesting comparable temperatures and wind geometries. IR photometric data reveals a similarly dusty circumstellar environment, although historical mass loss appears to have been heavier in IRC +10420. The systemic velocity implies a distance compatible with the red supergiant-dominated complex at the base of the Scutum Crux arm; the resultant luminosity determination is consistent with a physical association but suggests a lower initial mass than inferred for IRC +10420 (≲20 M⊙ versus ~40 M⊙). Evolutionary predictions for the physical properties of supernova progenitors derived from ~18–20 M⊙ stars – or ~12–15 M⊙ stars that have experienced enhanced mass loss as red supergiants – compare favourably with those of IRAS 18357-0604, which in turn appears to be similar to the the progenitor of SN2011dh; it may therefore provide an important insight into the nature of the apparently H-depleted yellow hypergiant progenitors of some Type IIb SNe
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A short survey of discourse representation models
With the advancement of technology and the wide adoption of ontologies as knowledge representation formats, in the last decade, a handful of models were proposed for the externalization of the rhetoric and argumentation captured within scientific publications. Conceptually, most of these models share a similar representation form of the scientific publication, i.e. as a series of interconnected elementary knowledge items. The main differences are given by the terminology used, the types of rhetorical and/or argumentation relations connecting the knowledge items and the foundational theories supporting these relations. This paper analyzes the state of the art and provides a concise comparative overview of the five most prominent discourse representation models, with the goal of sketching an unified model for discourse representation
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