The Schr\"odinger Functional for Improved Gluon and Quark Actions

The Schr\"odinger Functional (quantum/lattice field theory with Dirichlet boundary conditions) is a powerful tool in the non-perturbative improvement and for the study of other aspects of lattice QCD. Here we adapt it to improved gluon and quark actions, on isotropic as well as anisotropic lattices. Specifically, we describe the structure of the boundary layers, obtain the exact form of the classically improved gauge action, and outline the modifications necessary on the quantum level. The projector structure of Wilson-type quark actions determines which field components can be specified at the boundaries. We derive the form of O(a) improved quark actions and describe how the coefficients can be tuned non-perturbatively. There is one coefficient to be tuned for an isotropic lattice, three in the anisotropic case. Our ultimate aim is the construction of actions that allow accurate simulations of all aspects of QCD on coarse lattices.Comment: 39 pages, LaTeX, 11 embedded eps file

Paralysis due to the high tackle - a black spot South African rugby

The high tackle around the neck is illegal but still commonplace in South African rugby. An analysis of 40 rugby players who sustained spinal cord injury during the period 1985 1989 revealed that 8 were injured by a high tackle. The case histories and radiographs of these 8 players were analysed. The majority sustained flexion-rotation injuries after being tackled from the side. Another mechanism of injury was hyper-extension during a tackle from the rear. Disturbingly, 4 of the 8 players sustained ·complete permanent paralysis. This was consequent upon the orthopaedic injuries sustained - specifically facet dislocations or 'tear-drop' fractures, both injuries carrying with them a high risk of serious spinal cord injury. It is concluded that foul play in the form of the high tackle is still a major cause of serious spinal cord injury in South African rugby

Monte Carlo evaluation of FADE approach to anomalous kinetics

In this paper we propose a comparison between the CTRW (Monte Carlo) and Fractional Derivative approaches to the modelling of anomalous diffusion phenomena in the presence of an advection field. Galilei variant and invariant schemes are revised.Comment: 13 pages, 6 figure

Distribution of Time-Averaged Observables for Weak Ergodicity Breaking

We find a general formula for the distribution of time-averaged observables for systems modeled according to the sub-diffusive continuous time random walk. For Gaussian random walks coupled to a thermal bath we recover ergodicity and Boltzmann's statistics, while for the anomalous subdiffusive case a weakly non-ergodic statistical mechanical framework is constructed, which is based on L\'evy's generalized central limit theorem. As an example we calculate the distribution of $\bar{X}$: the time average of the position of the particle, for unbiased and uniformly biased particles, and show that $\bar{X}$ exhibits large fluctuations compared with the ensemble average $$.Comment: 5 pages, 2 figure

A non-perturbative determination of Z_V and b_V for O(a) improved quenched and unquenched Wilson fermions

By considering the local vector current between nucleon states and imposing charge conservation we determine, for $O(a)$ improved Wilson fermions, its renormalisation constant and quark mass improvement coefficient. The computation is performed for both quenched and two flavour unquenched fermions.Comment: 3 pages, 4 figures, Lattice(2002)(improve

Impact of caregiver burden on health-related quality of life and family functioning of carers of children with epilepsy at the Charlotte Maxeke Johannesburg Academic Hospital, South Africa

Background. The impact of caring for a child with a chronic disease on caregivers and their family functioning contributes to the child’s adaptation to the disease. Objectives. To determine the impact of caregiver burden on the health-related quality of life (HRQOL) and family functioning of carers of children with epilepsy (CWE), and to determine factors associated with a high impact of caregiver burden. Method. A cross-sectional study was conducted among primary caregivers of CWE attending the Charlotte Maxeke Johannesburg Academic Hospital, South Africa. Participants had been involved in childcare for at least 6 months before study enrolment and all gave informed consent. Data regarding sociodemographic and epilepsy-related variables were obtained from questionnaires, including the 36-item family impact module of the Pediatric Quality of Life assessment tool. Scores in the lower quartile were considered indicative of a negative impact on HRQOL and poor family functioning. Results. Participants identified as experiencing a high impact of paediatric epilepsy care reported raw scores ≤31.3 for both caregiver burden and family functioning. The family functioning score correlated strongly with the caregivers’ HRQOL score (p=0.78; p<0.001). Multivariate analysis identified a low level of education among caregivers and a high seizure frequency in patients as independent predictors of caregiver burden associated with a negative impact. Conclusion. Our findings suggest that the burden of caregiving in paediatric epilepsy among our study population impacts negatively on family functioning. The burden of care was associated with a low level of caregiver education and a high seizure frequency in their children

Non-perturbative scale evolution of four-fermion operators

We apply the Schroedinger Functional (SF) formalism to determine the renormalisation group running of four-fermion operators which appear in the effective weak Hamiltonian of the Standard Model. Our calculations are done using Wilson fermions and the parity-odd components of the operators. Preliminary results are presented for the operator $O_{VA}=(\bar s \gamma_\mu d)(\bar s \gamma_\mu \gamma_5 d)$.Comment: Lattice2002(improve

Some Insights in Superdiffusive Transport

In this paper we deal with high-order corrections for the Fractional Derivative approach to anomalous diffusion, in super-diffusive regime, which become relevand whenever one attempts to describe the behavior of particles close to normal diffusion.Comment: 14 pages, 7 figure