Drag coefficients for partially inflated flat circular parachutes

Free-body tests of flat circular parachutes and determination of aerodynamic drag coefficients during partial inflatio

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

Using a Fermionic Ensemble of Systems to Determine Excited States

We discuss a new numerical method for the determination of excited states of a quantum system using a generalization of the Feynman-Kac formula. The method relies on introducing an ensemble of non-interacting identical systems with a fermionic statistics imposed on the systems as a whole, and on determining the ground state of this fermionic ensemble by taking the large time limit of the Euclidean kernel. Due to the exclusion principle, the ground state of an $n$-system ensemble is realized by the set of individual systems occupying successively the $n$ lowest states, all of which can therefore be sampled in this way. To demonstrate how the method works, we consider a one-dimensional oscillator and a chain of harmonically coupled particles.Comment: 14 pages, Latex + 4 eps 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

A scalable PC-based parallel computer for lattice QCD

A PC-based parallel computer for medium/large scale lattice QCD simulations is suggested. The Eotvos Univ., Inst. Theor. Phys. cluster consists of 137 Intel P4-1.7GHz nodes. Gigabit Ethernet cards are used for nearest neighbor communication in a two-dimensional mesh. The sustained performance for dynamical staggered(wilson) quarks on large lattices is around 70(110) GFlops. The exceptional price/performance ratio is below $1/Mflop.Comment: 3 pages, 2 figures, Lattice2002(machines

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

Finite size effects on MπM_\pi in QCD from Chiral Perturbation Theory

We present a determination of the shift $M_\pi(L)-M_\pi$ due to the finite spatial box size $L$ by means of $N_f=2$ Chiral Perturbation Theory and L\"uscher's formula. The range of applicability of the chiral prediction is discussed.Comment: 3 pages, 3 figures, Lattice2002(spectrum