Evaluation of a closed-circuit television display in landing operations with a helicopter

Evaluating closed circuit television display in helicopter landing operation

On the n -> 0 limit of gamma_gg(a) in QCD

We consider the n -> 0 limit of the DGLAP splitting function gamma_gg(a) at all orders in the strong coupling constant, a, by analysing the leading order large N_f form of the associated d-dimensional critical exponent. We show that for unpolarized scattering the pole at n = 0 which appears in successive orders in perturbation theory is absent in the resummed expression.Comment: 7 latex page

UV finiteness of 3D Yang-Mills theories with a regulating mass in the Landau gauge

We prove that three-dimensional Yang-Mills theories in the Landau gauge supplemented with a infrared regulating, parity preserving mass term are ultraviolet finite to all orders. We also extend this result to the Curci-Ferrari gauge.Comment: 6 page

Three loop MSbar operator correlation functions for deep inelastic scattering in the chiral limit

We compute a variety of operator-operator correlation functions to third order in the MSbar scheme in the chiral limit. These include combinations of quark bilinear currents with gauge invariant operators such as moments n = 2 and 3 of the flavour non-singlet Wilson operators of deep inelastic scattering and moment n = 2 of the transversity operator, as well as the correlation functions of the latter operators with themselves. The explicit values of these gauge independent correlation functions are required to assist with non-perturbative matching to lattice regularized calculations of the same quantities. As part of the computation we determine the mixing matrix of renormalization constants of these non-singlet currents with their associated total derivative operators at the same twist to three loops in MSbar. Such operators are crucial in extracting renormalization constants for the operator-operator correlation functions which are consistent with the corresponding renormalization group equation. As a by-product we deduce the R-ratio for the tensor current to third order in the MSbar scheme.Comment: 38 latex pages, 2 figure

Off-diagonal mass generation for Yang-Mills theories in the maximal Abelian gauge

We investigate a dynamical mass generation mechanism for the off-diagonal gluons and ghosts in SU(N) Yang-Mills theories, quantized in the maximal Abelian gauge. Such a mass can be seen as evidence for the Abelian dominance in that gauge. It originates from the condensation of a mixed gluon-ghost operator of mass dimension two, which lowers the vacuum energy. We construct an effective potential for this operator by a combined use of the local composite operators technique with algebraic renormalization and we discuss the gauge parameter independence of the results. We also show that it is possible to connect the vacuum energy, due to the mass dimension two condensate discussed here, with the non-trivial vacuum energy originating from the condensate , which has attracted much attention in the Landau gauge.Comment: 15 pages. Revtex. 1 .eps figure. Talk given by D.Dudal at XXV Encontro Nacional de Fisica de Particulas e Campos, Caxambu, Minas Gerais, Brasil, 24-28 Aug 2004. To appear in Brazilian Journal of Physic

Phase transition and critical behaviour of the d=3 Gross-Neveu model

A second order phase transition for the three dimensional Gross-Neveu model is established for one fermion species N=1. This transition breaks a paritylike discrete symmetry. It constitutes its peculiar universality class with critical exponent \nu = 0.63 and scalar and fermionic anomalous dimension \eta_\sigma = 0.31 and \eta_\psi = 0.11, respectively. We also compute critical exponents for other N. Our results are based on exact renormalization group equations.Comment: 4 pages, 1 figure; v4 corresponds to the published articl

'HeART of Stroke (HoS)', a community-based Arts for Health group intervention to support self-confidence and psychological well-being following a stroke: protocol for a randomised controlled feasibility study

Introduction Over 152 000 people in the UK have strokes annually and a third experience residual disability. Low mood also affects a third of stroke survivors; yet psychological support is poor. While Arts for Health interventions have been shown to improve well-being in people with mild-to-moderate depression post-stroke, their role in helping people regain sense of self, well-being and confidence has yet to be evaluated. The main aim of this study is to explore the feasibility of conducting a pragmatic multicentre randomised controlled trial to assess the effectiveness and cost-effectiveness of an Arts for Health group intervention (‘HeART of Stroke’ (HoS)) for stroke survivors. HoS is a 10-session artist-facilitated group intervention held in the community over 14 weeks. It offers a non-judgemental, supportive environment for people to explore sense of self, potentially enhancing well-being and confidence. Methods and analysis Sixty-four people, up to 2 years post-stroke, recruited via secondary care research staff or community stroke/rehabilitation teams in two UK centres will be randomised to either HoS plus usual care or usual care only. Self-reported outcomes, measured at baseline and approximately 5 months postrandomisation, will include stroke-related, well-being, mood, self-esteem, quality of life and process measures. Analyses will focus on estimating key feasibility parameters (eg, rates of recruitment, retention, intervention attendance). We will develop outcome and resource use data collection methods to inform an effectiveness and cost-effectiveness analysis in the future trial. Interviews, with a sample of participants, will explore the acceptability of the intervention and study processes, as well as experiences of the HoS group. Ethics and dissemination National Health Service (NHS), Research and Development and University ethical approvals have been obtained. Two peer-reviewed journal publications are planned plus one service user led publication. Findings will be disseminated at key national conferences, local stakeholder events and via institutional websites.This paper presents independent research funded by the National Institute for Health Research (NIHR) under its Research for Patient Benefit (RfPB) Programme (Grant Reference Number PB-PG-0212-27054)