Equilibrium and off-equilibrium simulations of the 4d Gaussian spin glass

In this paper we study the on and off-equilibrium properties of the four dimensional Gaussian spin glass. In the static case we determine with more precision that in previous simulations both the critical temperature as well as the critical exponents. In the off-equilibrium case we settle the general form of the autocorrelation function, and show that is possible to obtain dynamically, for the first time, a value for the order parameter.Comment: 16 pages and 13 figures, uses epsfig.sty and rotate.sty. Some minor grammatical changes. Also available at http://chimera.roma1.infn.it/index_papers_complex.htm

Semileptonic B→ρB \to \rho and B→πB \to \pi Decays: Lattice and Dispersive Constraints

I present two recent pieces of work on semileptonic $B \to \pi, \rho$ decays where it is shown how lattice QCD calculations can be used to test heavy-quark symmetry and determine phenomenologically relevant quantities despite the limits on these calculations' kinematical reach. The study of semileptonic $B \to \rho$ decays was performed with the UKQCD Collaboration.Comment: LaTeX, 7 pages, 4 PostScript figures. Calls twoside.sty, fleqn.sty, espcrc2.sty and epsf.sty. Talk given at the High Energy Conference on Quantum Chromodynamics (QCD 96), Montpellier, France, 4-12$^{th}$ July 1996. To appear in the proceeding

African Agricultural Research and Advisory Services under Climate Change: Perspectives from an E-­Discussion

This paper presents some of the information presented and views expressed, during a three-week e-discussion on the issue of climate change within African agricultural research and advisory services. For us, as organisers, the results were surprising, in that participants departed strongly and significantly from the questions we had wanted them to answer, and raised different and broader issues, that we might have regarded as tangential but which provided significant learning for us on the questions of climate change and agriculture

Dynamical fat link fermions

The use of APE smearing or other blocking techniques in fermion actions can provide many advantages. There are many variants of these fat link actions in lattice QCD currently, such as FLIC fermions. Frequently, fat link actions make use of the APE blocking technique in combination with a projection of the blocked links back into the special unitary group. This reunitarisation is often performed using an iterative maximisation of a gauge invariant measure. This technique is not differentiable with respect to the gauge field and thus prevents the use of standard Hybrid Monte Carlo simulation algorithms. The use of an alternative projection technique circumvents this difficulty and allows the simulation of dynamical fat link fermions with standard HMC and its variants.Comment: LHP '03 (Cairns) Proceeding

The Geoff Egan Memorial Lecture 2011. Artefacts, art and artifice: reconsidering iconographic sources for archaeological objects in early modern Europe

A first systematic analysis of historic domestic material culture depicted in contemporaneous Western painting and prints, c.1400-1800. Drawing on an extensive data set, the paper proposes to methodologies and hermeneutics for historical analysis and archaeological correspondence

Generalised Spin Projection for Fermion Actions

The majority of compute time doing lattice QCD is spent inverting the fermion matrix. The time that this takes increases with the condition number of the matrix. The FLIC(Fat Link Irrelevant Clover) action displays, among other properties, an improved condition number compared to standard actions and hence is of interest due to potential compute time savings. However, due to its two different link sets there is a factor of two cost in floating point multiplications compared to the Wilson action. An additional factor of two has been attributed due to the loss of the so-called spin projection trick. We show that any split-link action may be written in terms of spin projectors, reducing the additional cost to at most a factor of two. Also, we review an efficient means of evaluating the clover term, which is additional expense not present in the Wilson action.Comment: 4 page

Recent development and perspectives of machines for lattice QCD

I highlight recent progress in cluster computer technology and assess status and prospects of cluster computers for lattice QCD with respect to the development of QCDOC and apeNEXT. Taking the LatFor test case, I specify a 512-processor QCD-cluster better than 1$/Mflops.Comment: 14 pages, 17 figures, Lattice2003(plenary

Confining strings in representations with common nn-ality

We study the spectrum of confining strings in SU(3) pure gauge theory, by means of lattice Monte Carlo simulations, using torelon operators in different representations of the gauge group. Our results provide direct evidence that the string spectrum is according to predictions based on $n$-ality. Torelon correlations in the rank-2 symmetric channel appear to be well reproduced by a two-exponential picture, in which the lowest state is given by the fundamental string $\sigma_1=\sigma$, the heavier string state is such that the ratio $\sigma_2/\sigma_1$ is approximately given by the Casimir ratio $C_{\rm sym}/C_{\rm f} = 5/2$, and the torelon has a much smaller overlap with the lighter fundamental string state.Comment: 7 pages, 2 figure

The Lexicography and Significance of Ranks and Ranking in the Nigeria Police Force

Appropriate communication requires the use of appropriate words in a given context. Most often, people find it difficult to communicate accurately because of their dearth of knowledge of the appropriate vocabularies or registers to use in each situation. The Nigeria Police Force (NPF) and the Nigerian armed forces tend to prove some reasonable level of difficulty for people to discuss as they are not conversant with the terms and terminologies used in the forces. To proffer a little solution in this direction, this paper embarks on a presentation and discussion of ranks and ranking in the Nigeria Police Force (NPF), bringing out the implications of such old-time practice in the force. It is obvious that ranks and ranking are but a minute aspect of the Nigeria Police Force (NPF), meaning many other aspects abound for further discussion. This paper therefore leaves room for other scholars to investigate into those other aspects for the ease of linguistic and professional communications in the domain of the Nigeria Police Force (NPF). Keywords: Lexicograghy, Ranks, Ranking, Nigeria Police Forc