Efficiency of different matrix inversion methods applied to Wilson fermions

We compare different conjugate gradient -- like matrix inversion methods (CG, BiCGstab1 and BiCGstab2) employing for this purpose the compact lattice quantum electrodynamics (QED) with Wilson fermions. The main goals of this investigation are the CPU time efficiency of the methods as well as the influence of machine precision on the reliability of (physical) results especially close to the 'critical' line ~\kappa_c(\bt).Comment: 27 pages LaTeX (epsf), all figures include

SU(3) Latent Heat and Surface Tension from Tree Level and Tadpole Improved Actions

We analyze the latent heat and surface tension at the SU(3) deconfinement phase transition with tree level and tadpole improved Symanzik actions on lattices with temporal extent $N_\tau = 3$ and 4 and spatial extent $N_\sigma/ N_\tau = 4$, 6 and 8. In comparison to the standard Wilson action we do find a drastic reduction of cut-off effects already with tree level improved actions. On lattices with temporal extent $N_\tau=4$ results for the surface tension and latent heat obtained with a tree level improved action agree well with those obtained with a tadpole improved action. A comparison with $N_\tau=3$ calculations, however, shows that results obtained with tadpole action remain unaffected by cut-off effects even on this coarse lattice, while the tree level action becomes sensitive to the cut-off. For the surface tension and latent heat we find $\sigma_I/ T_c^3 = 0.0155~(16)$ and $\Delta\epsilon/T_c^4 = 1.40~(9)$, respectively.Comment: 11 pages, LaTeX2e File, 3 Postscript figure

The SU(3) deconfining phase transition with Symanzik action

We report on the determination of the deconfining temperature in SU(3) pure gauge theory, using the Symanzik tree level improved action, on lattices of size 3 x 12^3, 4 x 16^3, 5 x 20^3, 6 x24^3. We find that the asymptotic scaling violation pattern is similar to the one observed using the Wilson action. We conclude that the irrelevant operators do not affect, in the range of couplings considered, the lattice beta function. An analysis based on an effective coupling formulation shows an apparent improvement.Comment: 8 pages, report IFUP-TH 12/9

The two-phase issue in the O(n) non-linear σ\sigma-model: A Monte Carlo study

We have performed a high statistics Monte Carlo simulation to investigate whether the two-dimensional O(n) non-linear sigma models are asymptotically free or they show a Kosterlitz- Thouless-like phase transition. We have calculated the mass gap and the magnetic susceptibility in the O(8) model with standard action and the O(3) model with Symanzik action. Our results for O(8) support the asymptotic freedom scenario.Comment: 3 pgs. espcrc2.sty included. Talk presented at LATTICE96(other models

Estimation of minimally important differences in EQ-5D utility and VAS scores in cancer

We wish to correct a mistake in the abstract and conclusion of our published paper [1]. In the abstract and conclusion, the MID for EQ-VAS score should be reported as 7 rather than 0.07. EQ-VAS scores range from 0 to 100, while EQ-5D index-based scores are anchored by 0 (dead) and 1 (perfect health). The specific wording in the conclusion of the abstract should read “Important differences in EQ-5D utility and VAS scores were similar for all cancers and lung cancer, with the lower end of the range of estimates closer to the MID, i. e. 0.08 for UK-index scores, 0.06 for US-index scores, and 7 for VAS scores. Author details

Structural validation of a realistic wing structure: the RIBES test article

Several experimental test cases are available in literature to study and validate fluid structure interaction methods. They, however, focus the attention mainly on replicating typical cruising aerodynamic conditions forcing the adoption of fully steel made models able to operate with the high loads generated in high speed facilities. This translates in a complete loss of similitude with typical realistic aeronautical wing structures configurations. To reverse this trend, and to better study the aerolastic mechanism from a structural point of view, an aeroelastic measurement campaign was carried within the EU RIBES project. A half wing model for wind tunnel tests was designed and manufactured replicating a typical metallic wing box structure, producing a database of loads, pressure, stress and deformation measurements. In this paper the design, manufacturing and validation activities performed within the RIBES project are described, with a focus on the structural behavior of the test article. All experimental data and numerical models are made freely available to the scientific community

Two-photon excitation selective plane illumination microscopy (2PE-SPIM) of highly scattering samples: Characterization and application

In this work we report the advantages provided by two photon excitation (2PE) implemented in a selective plane illumination microscopy (SPIM) when imaging thick scattering samples. In particular, a detailed analysis of the effects induced on the real light sheet excitation intensity distribution is performed. The comparison between single-photon and twophoton excitation profiles shows the reduction of the scattering effects and sample-induced aberrations provided by 2PE-SPIM. Furthermore, uniformity of the excitation distribution and the consequent improved image contrast is shown when imaging scattering phantom samples in depth by 2PE-SPIM. These results show the advantages of 2PE-SPIM and suggest how this combination can further enhance the SPIM performance. Phantom samples have been designed with optical properties compatible with biological applications of interest. © 2013 Optical Society of America