Preconditioning of Improved and ``Perfect'' Fermion Actions

We construct a locally-lexicographic SSOR preconditioner to accelerate the parallel iterative solution of linear systems of equations for two improved discretizations of lattice fermions: the Sheikholeslami-Wohlert scheme where a non-constant block-diagonal term is added to the Wilson fermion matrix and renormalization group improved actions which incorporate couplings beyond nearest neighbors of the lattice fermion fields. In case (i) we find the block llssor-scheme to be more effective by a factor about 2 than odd-even preconditioned solvers in terms of convergence rates, at beta=6.0. For type (ii) actions, we show that our preconditioner accelerates the iterative solution of a linear system of hypercube fermions by a factor of 3 to 4.Comment: 27 pages, Latex, 17 Figures include

The analysis of 2-amino-2-thiazoline-4-carboxylic acid in the plasma of smokers and non-smokers

ATCA (2-amino-2-thiazoline-4-carboxylic acid) is a promising marker to assess cyanide exposure because of several advantages of ATCA analysis over direct determination of cyanide and alternative cyanide biomarkers (i.e. stability in biological matrices, consistent recovery, and relatively small endogenous concentrations). Concentrations of ATCA in the plasma of smoking and non-smoking human volunteers were analyzed using gas-chromatography mass-spectrometry to establish the feasibility of using ATCA as a marker for cyanide exposure. The levels of ATCA in plasma of smoking volunteers, 17.2 ng/ml, were found to be significantly (p < 0.001) higher than that of non-smoking volunteers, 11.8 ng/ml. Comparison of ATCA concentrations of smokers relative to non-smokers in both urine and plasma yielded relatively similar results. The concentration ratio of ATCA for smokers versus non-smokers in plasma and urine was compared to similar literature studies of cyanide and thiocyanate, and correlations are discussed. This study supports previous evidence that ATCA can be used to determine past cyanide exposure and indicates that further studies should be pursued to validate the use of ATCA as a marker of cyanide exposure

Toxic risks involved in the use of disinfectants on the skin

Translated from German (Hygiene and Medizin 1987 no. 12 p. 134-142)Available from British Library Document Supply Centre-DSC:9022.381(HSE-Trans--16002)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Die Bestimmung der Deltaaminolaevulinsaeure im Urin von Krippenkindern in Berlin (DDR) als Indikator fuer die kommunale Bleibelastung

HUB(11) - 83 HB 4436 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Preconditioning of Improved and &quot;Perfect&quot; Fermion Actions

We construct a locally-lexicographic SSOR preconditioner to accelerate the parallel iterative solution of linear systems of equations for two improved discretizations of lattice fermions: (i) the Sheikholeslami-Wohlert scheme where a non-constant block-diagonal term is added to the Wilson fermion matrix and (ii) renormalization group improved actions which incorporate couplings beyond nearest neighbors of the lattice fermion fields. In case (i) we find the block ll -SSOR-scheme to be more effective by a factor ß 2 than odd-even preconditioned solvers in terms of convergence rates, at fi = 6:0. For type (ii) actions, we show that our preconditioner accelerates the iterative solution of a linear system of hypercube fermions by a factor of 3 to 4. Keywords: lattice QCD, improved actions, perfect actions, hypercube fermions, SSOR preconditioning 1 Introduction Traditionally, simulations of lattice quantum chromodynamics (QCD) were based on nearest-neighbor finite difference approximations..

Comparison of direct growth and wafer bonding for the fabrication of GaInP/GaAs dual-junction solar cells on silicon

Two different process technologies were investigated for the fabrication of high-efficiency GaInP/GaAs dual-junction solar cells on silicon: direct epitaxial growth and layer transfer combined with semiconductor wafer bonding. The intention of this research is to combine the advantages of high efficiencies in III-V tandem solar cells with the low cost of silicon. Direct epitaxial growth of a GaInP/GaAs dual-junction solar cell on a GaAsyP1-y buffer on silicon yielded a 1-sun efficiency of 16.4% (AM1.5g). Threading dislocations that result from the 4% lattice grading are still the main limitation to the device performance. In contrast, similar devices fabricated by semiconductor wafer bonding on n-type inactive Si reached efficiencies of 26.0% (AM1.5g) for a 4-cm2 solar cell device

Thiocyanate concentration in saliva of cystic fibrosis patients.

Thiocyanates (SCN-) are ubiquitous in nature. There are indispensable part of host defense system that act as a substrate for lactoperoxidase (LPO). In our study we present initial data on SCN- concentration in saliva of CF patients in comparison to healthy non-smokers and healthy smokers. 5 ml of saliva was collected from each subject to a sterile tube and thiocyanate concentration was measured in each sample. The results of the measurements are presented on Fig. 1. Mean concentration of SCN- in saliva of CF patients was 0.031 +/- 0.0052 g/l, in healthy non-smokers 0.039 +/- 0.0048 g/l and in healthy smokers 0.048 +/- 0.0161 g/l. The differences between each group were statistically significant. Studies on larger group of patients and probably on different material (BALF or induced sputum) should present interesting data complementing the in vitro studies