Accelerating Staggered Fermion Dynamics with the Rational Hybrid Monte Carlo (RHMC) Algorithm

Improved staggered fermion formulations are a popular choice for lattice QCD calculations. Historically, the algorithm used for such calculations has been the inexact R algorithm, which has systematic errors that only vanish as the square of the integration step-size. We describe how the exact Rational Hybrid Monte Carlo (RHMC) algorithm may be used in this context, and show that for parameters corresponding to current state-of-the-art computations it leads to a factor of approximately seven decrease in cost as well as having no step-size errors.Comment: 4 pages, 2 figures, 1 tabl

Descriptions of new luperine genera and species from Mexico : with keys to related taxa (Coleoptera: Chrysomelidae: Galerucinae)

The section Scelidites ofthe subtribe Luperina is diagnosed and described. A key is provided to separate the genera within this section. Cyphotarsis Jacoby is reduced to a junior synonym of Metacoryna Jacoby. Microscelida, new genus, is erected to include Agelastica viridis Jacoby, Luperus subcostatus Jacoby, Luperus subglabratus Jacoby, Scelidopsis violacea Jacoby, and seven newly described species. A key and diagnoses are provided to enable recognition of each species within this new genus. Scelidacne, new genus, is erected to include a single newly described species

The Western North American Genus Androlyperus Crotch, 1873 (Coleoptera: Chrysomelidae: Galerucinae)

The five previously known species of Androlyperus are redescribed and diagnosed. Androlyperus nataliae n. sp. is described from the Baja California Peninsula, Mexico. A taxonomic key is provided to facilitate species identification

The Rational Hybrid Monte Carlo Algorithm

The past few years have seen considerable progress in algorithmic development for the generation of gauge fields including the effects of dynamical fermions. The Rational Hybrid Monte Carlo (RHMC) algorithm, where Hybrid Monte Carlo is performed using a rational approximation in place the usual inverse quark matrix kernel is one of these developments. This algorithm has been found to be extremely beneficial in many areas of lattice QCD (chiral fermions, finite temperature, Wilson fermions etc.). We review the algorithm and some of these benefits, and we compare against other recent algorithm developements. We conclude with an update of the Berlin wall plot comparing costs of all popular fermion formulations.Comment: 15 pages. Proceedings from Lattice 200

The impact on incentives of five years of social security reform in the UK

The UK’s Labour Government has expanded means-testing of social security but attempted to do so while minimising the disincentive effects typically associated with such an approach. We test whether it has succeeded by reviewing the effect of 5 years of reforms on a range of incentives across the British population, undertaking micro-simulations on survey data. The incentive to enter work increases for the first earner in families, but for second-earners in couples the incentive to work has generally been dulled. Effective marginal tax rates have generally increased for workers, in spite of reductions in benefit withdrawal rates, owing to the increasing numbers facing means-tested benefit withdrawal. Reforms have reduced the number of pensioners facing very high effective marginal rates, but increased the number on moderately high rates. Incentives regarding family life have been affected: partnering has become less financially attractive for low-income individuals; having children has become more financially attractive

A history of the city of Somerville for the first four grades

Thesis (Ed.M.)--Boston Universit