A Study of the N=2N=2 Kazakov-Migdal Model

We study numerically the SU(2) Kazakov-Migdal model of `induced QCD'. In contrast to our earlier work on the subject we have chosen here {\it not} to integrate out the gauge fields but to keep them in the Monte Carlo simulation. This allows us to measure observables associated with the gauge fields and thereby address the problem of the local $Z_2$ symmetry present in the model. We confirm our previous result that the model has a line of first order phase transitions terminating in a critical point. The adjoint plaquette has a clear discontinuity across the phase transition, whereas the plaquette in the fundamental representation is always zero in accordance with Elitzur's theorem. The density of small $Z_2$ monopoles shows very little variation and is always large. We also find that the model has extra local U(1) symmetries which do not exist in the case of the standard adjoint theory. As a result, we are able to show that two of the angles parameterizing the gauge field completely decouple from the theory and the continuum limit defined around the critical point can therefore not be `QCD'.Comment: 11 pages, UTHEP-24

National Evaluation of the Capacity Building Programme in English Local Government: Evaluation of the National Programmes: Annex 2: Evaluation of the National Programmes

The report is one of a series of outputs from the national evaluation of the CBP, being undertaken by a team of researchers at the Policy Research Institute (PRI) at Leeds Metropolitan University and the Cities Research Unit at the University of West of England. The Capacity Building Programme for local government was launched in 2003 as a joint Department for Communities and Local Government (DCLG) / Local Government Association (LGA) initiative to support capacity building and improvement activities within local authorities in England. The evaluation of the Capacity Building Programme has been underway since late 2004. A scoping phase was conducted until May 2005, including a short evaluation of the Pilot Programmes. The main phase of the evaluation commenced in September 2005 and encompassed four main phases (see Section 1.3: p10)

Asymptotics of Expansion of the Evolution Operator Kernel in Powers of Time Interval Δt\Delta t

The upper bound for asymptotic behavior of the coefficients of expansion of the evolution operator kernel in powers of the time interval \Dt was obtained. It is found that for the nonpolynomial potentials the coefficients may increase as $n!$. But increasing may be more slow if the contributions with opposite signs cancel each other. Particularly, it is not excluded that for number of the potentials the expansion is convergent. For the polynomial potentials \Dt-expansion is certainly asymptotic one. The coefficients increase in this case as $\Gamma(n \frac{L-2}{L+2})$, where $L$ is the order of the polynom. It means that the point \Dt=0 is singular point of the kernel.Comment: 12 pp., LaTe

Cost Utility of Omalizumab Compared with Standard of Care for the Treatment of Chronic Spontaneous Urticaria.

BACKGROUND: Chronic spontaneous urticaria (CSU) negatively impacts patient quality of life and productivity and is associated with considerable indirect costs to society. OBJECTIVE: The aim of this study was to assess the cost utility of add-on omalizumab treatment compared with standard of care (SOC) in moderate or severe CSU patients with inadequate response to SOC, from the UK societal perspective. METHODS: A Markov model was developed, consisting of health states based on Urticaria Activity Score over 7 days (UAS7) and additional states for relapse, spontaneous remission and death. Model cycle length was 4 weeks, and total model time horizon was 20 years in the base case. The model considered early discontinuation of non-responders (response: UAS7 ≤6) and retreatment upon relapse (relapse: UAS7 ≥16) for responders. Clinical and cost inputs were derived from omalizumab trials and published sources, and cost utility was expressed as incremental cost-effectiveness ratios (ICERs). Scenario analyses included no early discontinuation of non-responders and an altered definition of response (UAS7 <16). RESULTS: With a deterministic ICER of £3183 in the base case, omalizumab was associated with increased costs and benefits relative to SOC. Probabilistic sensitivity analysis supported this result. Productivity inputs were key model drivers, and individual scenarios without early discontinuation of non-responders and adjusted response definitions had little impact on results. ICERs were generally robust to changes in key model parameters and inputs. CONCLUSIONS: In this, the first economic evaluation of omalizumab in CSU from a UK societal perspective, omalizumab consistently represented a treatment option with societal benefit for CSU in the UK across a range of scenarios

Implementation of on-site velocity boundary conditions for D3Q19 lattice Boltzmann

On-site boundary conditions are often desired for lattice Boltzmann simulations of fluid flow in complex geometries such as porous media or microfluidic devices. The possibility to specify the exact position of the boundary, independent of other simulation parameters, simplifies the analysis of the system. For practical applications it should allow to freely specify the direction of the flux, and it should be straight forward to implement in three dimensions. Furthermore, especially for parallelized solvers it is of great advantage if the boundary condition can be applied locally, involving only information available on the current lattice site. We meet this need by describing in detail how to transfer the approach suggested by Zou and He to a D3Q19 lattice. The boundary condition acts locally, is independent of the details of the relaxation process during collision and contains no artificial slip. In particular, the case of an on-site no-slip boundary condition is naturally included. We test the boundary condition in several setups and confirm that it is capable to accurately model the velocity field up to second order and does not contain any numerical slip.Comment: 13 pages, 4 figures, revised versio

Self-Similar Bootstrap of Divergent Series

A method is developed for calculating effective sums of divergent series. This approach is a variant of the self-similar approximation theory. The novelty here is in using an algebraic transformation with a power providing the maximal stability of the self-similar renormalization procedure. The latter is to be repeated as many times as it is necessary in order to convert into closed self-similar expressions all sums from the series considered. This multiple and complete renormalization is called self-similar bootstrap. The method is illustrated by several examples from statistical physics.Comment: 1 file, 22 pages, RevTe

The Sun's position in the sky

We express the position of the Sun in the sky as a function of time and the observer's geographic coordinates. Our method is based on applying rotation matrices to vectors describing points on the celestial sphere. We also derive direct expressions, as functions of date of the year and geographic latitude, for the duration of daylight, the maximum and minimum altitudes of the Sun, and the cardinal directions to sunrise and sunset. We discuss how to account for the eccentricity of the earth's orbit, the precessions of the equinoxes and the perihelion, the size of the solar disk, and atmospheric refraction. We illustrate these results by computing the dates of "Manhattanhenge" (when sunset aligns with the east-west streets on the main traffic grid for Manhattan, in New York City), by plotting the altitude of the Sun over representative cities as a function of time, and by showing plots ("analemmas") for the position of the Sun in the sky at a given hour of the day.Comment: 19 pages, 16 figures. v3: Replaced to match published version and to re-package Mathematica notebook as an ancillary fil

Generalised chiral QED2 : Anomaly and Exotic Statistics

We study the influence of the anomaly on the physical quantum picture of the generalized chiral Schwinger model defined on the circle. We show that the anomaly i) results in the background linearly rising electric field and ii) makes the spectrum of the physical Hamiltonian nonrelativistic without a massive boson. The physical matter fields acquire exotic statistics . We construct explicitly the algebra of the Poincare generators and show that it differs from the Poincare one. We exhibit the role of the vacuum Berry phase in the failure of the Poincare algebra to close. We prove that, in spite of the background electric field, such phenomenon as the total screening of external charges characteristic for the standard Schwinger model takes place in the generalized chiral Schwinger model, too.Comment: LATEX file, 36 pp., to appear in Phys.Rev.