Improved chiral properties of FLIC fermions

The chiral properties of the fat-link irrelevant clover (FLIC) fermion action are examined. The improved chiral properties of fermion actions incorporating smoothed links are realized in the FLIC action where only the irrelevant operators of the fermion action are constructed with smoothed links. In particular, the histogram of the additive mass renormalization encountered in chiral-symmetry breaking Wilson-type fermion actions is seen to narrow upon introducing fat-links in the irrelevant operators. The exceptional configuration problem of quenched QCD is reduced, enabling access to the light quark mass regime of m_#pi#/m_#rho# #propor to# 0.35. In particular, quenched chiral non-analytic behavior is revealed in the light quark mass dependence of the #DELTA#-baryon mass. FLIC fermions offer a promising approach to revealing the properties of full QCD at light quark masses. (orig.)Available from TIB Hannover: RA 8919(2004-074) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Cohomology of Lie superalgebras and of their generalizations

The cohomology groups of Lie superalgebras and, more generally, of #epsilon# Lie algebras, are introduced and investigated. The main emphasis is on the case where the module of coefficients is non-trivial. Two general propositions are proved, which help to calculate the cohomology groups. Several examples are included to show the peculiarities of the super case. For L=sl(1 vertical stroke 2), the cohomology groups H"1(L, V) and H"2(L, V), with V a finite-dimensional simple graded L-module, are determined, and the result is used to show that H"2(L, U(L)) (with U(L) the enveloping algebra of L) is trivial. This implies that the algebra U(L) does not admit of any non-trivial formal deformation (in the sense of Gerstenhaber). Garland's theory of universal central extensions of Lie algebras is generalized to the case of #epsilon# Lie algebras. (orig.)Available from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Quark propagator in Landau gauge

The Landau gauge quark propagator in momentum space is investigated using the O(a)-improved Sheikholeslami-Wohlert (SW) quark action with a tree-level mean-field improved coefficient c_s_w. We have studied the unimproved definition of the quark propagator, as well as two different tree-level O(a)-improved propagators. The ultraviolet behavior of the free lattice propagator is studied for each of these in order to establish which of them provides the most reliable description of the quark propagator up to the medium momentum regime. A general method of tree-level correction is introduced. This exploits asymptotic freedom and removes much of the trivial lattice artifacts at medium to high momenta. We obtain results for the quark propagator which are qualitatively similar to those typically used in quark models. A simple extrapolation of the infrared quark mass M(p"2 = 0) to the chiral limit gives 298 #+-# 8 MeV, which is consistent with phenomenological expectations. (orig.)17 refs.Available from TIB Hannover: RA 2999(00-099) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Hybrid meson spectrum from the FLIC action

The spectral properties of hybrid meson interpolating fields are investigated. The quantum numbers of the meson are carried by smeared-source fermion operators and highly-improved chromo-electric and -magnetic field operators composed with APE-smeared links. The effective masses of standard and hybrid operators indicate that the ground state meson is effectively isolated using both standard and hybrid interpolating fields. Focus is placed on interpolating fields in which the large spinor components of the quark and antiquark fields are merged. In particular, the effective mass of the exotic 1"-"+ meson is reported. Further, we report some values for excited mesonic states using a variational process. (orig.)Available from TIB Hannover: RA 2999(03-207) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Systematic uncertainties in the precise determination of the strangeness magnetic moment of the nucleon

Systematic uncertainties in the recent precise determination of the strangeness magnetic moment of the nucleon are identified and quantified. In summary, G_M"s=-0.046 #+-# 0.019 #mu#_N. (orig.)SIGLEAvailable from TIB Hannover: RA 2999(05-014) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

The strangeness magnetic moment of the nucleon from FLIC fermions

By imposing the constraints of charge symmetry we show that the strangeness magnetic moment of the nucleon can be expressed in terms of empirical magnetic moments and ratios of valence quark magnetic moments. The latter are determined using modern chiral extrapolation techniques and recent low mass lattice QCD simulations of the individual quark contributions to the magnetic moments of the nucleon octet. The result is a precise determination of G_M"s, namely -0.043 #+-# 0.013 #mu#N, which is consistent with the latest experimental measurements. (orig.)SIGLEAvailable from TIB Hannover: RA 2999(03-211) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Electromagnetic form factors wih FLIC fermions

The Fat-Link Irrelevant Clover (FLIC) fermion action provides a new form of nonperturbative #sigma#(a) improvement and allows efficient access to the light quark-mass regime. FLIC fermions enable the construction of the nonperturbatively #sigma#(a)-improved conserved vector current without the difficulties associated with the fine tuning of the improvement coefficients. The simulations are performed with an #sigma#(a"2) mean-field improved plaquette-plus-rectangle gluon action on a 20"3 x 40 lattice with a lattice spacing of 0.128 fm, enabling the first simulation of baryon form factors at light quark masses on a large volume lattice. Magnetic moments, electric charge radii and magnetic radii are extracted from these form factors, and show interesting chiral nonanalytic behavior in the light quark mass regime. (orig.)Available from TIB Hannover: RA 2999(03-210) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

On the wall pressure field in turbulent pipe flow

SIGLEAvailable from Max-Planck-Institut fuer Stroemungsforschung, Goettingen Germany, F.R. / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Scaling of FLIC fermions

Hadron masses are calculated in quenched lattice QCD on a variety of lattices in order to probe the scaling behavior of the Fat-Link Irrelevant Clover (FLIC) fermion action, a fat-link clover fermion action in which the purely irrelevant operators of the fermion action are constructed using APE-smeared links. The scaling analysis indicates FLIC fermions provide a new form of nonperturbative O(a) improvement where near-continuum results are obtained at finite lattice spacing. (orig.)SIGLEAvailable from TIB Hannover: RA 2999(04-073) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

The cost-effectiveness of exenatide twice daily (BID) vs insulin lispro three times daily (TID) as add-on therapy to titrated insulin glargine in patients with type 2 diabetes

Objective: To evaluate the cost-effectiveness of exenatide twice daily (BID) vs bolus insulin lispro three times daily (TID) as add-on therapy when glycemic control is sub-optimal with titrated basal insulin glargine and metformin. Methods: The analysis was based on the recent 4B Study, which compared exenatide BID and lispro TID as add-on therapies in subjects with type 2 diabetes insufficiently controlled, despite titrated insulin glargine. The Cardiff Diabetes Model was used to simulate patient costs and health benefits beyond the 4B Study. The Swedish healthcare perspective was adopted for this analysis; costs are reported in €EUR to aid interpretation. The main outcome measure was the cost per quality-adjusted life-year (QALY) gained with exenatide BID compared to lispro TID. Results: Exenatide BID was associated with an incremental cost of €1,270 and a QALY increase of +0.64 compared with lispro TID over 40 years. The cost per QALY gained with exenatide BID compared with lispro TID was €1,971, which is within conventional limits of cost-effectiveness. Cost-effectiveness results were generally robust to alternative assumptions and values for key model parameters. Limitations: Extrapolation of trial data over the longer term can be influenced by modeling and parameter uncertainty. Cost-effectiveness results were generally insensitive to alternative values of key model input parameters and across scenarios. Conclusions: The addition of exenatide BID rather than insulin lispro to basal insulin is associated with similar or better clinical outcomes. Illustrated from the Swedish healthcare perspective, analysis with the Cardiff Diabetes Model demonstrated that exenatide BID represents a cost-effective treatment alternative to lispro TID as add-on therapy in type 2 diabetes patients insufficiently controlled on basal insulin