Scattering in three-dimensional fuzzy space

We develop scattering theory in a non-commutative space defined by a $su(2)$ coordinate algebra. By introducing a positive operator valued measure as a replacement for strong position measurements, we are able to derive explicit expressions for the probability current, differential and total cross-sections. We show that at low incident energies the kinematics of these expressions is identical to that of commutative scattering theory. The consequences of spacial non-commutativity are found to be more pronounced at the dynamical level where, even at low incident energies, the phase shifts of the partial waves can deviate strongly from commutative results. This is demonstrated for scattering from a spherical well. The impact of non-commutativity on the well's spectrum and on the properties of its bound and scattering states are considered in detail. It is found that for sufficiently large well-depths the potential effectively becomes repulsive and that the cross-section tends towards that of hard sphere scattering. This can occur even at low incident energies when the particle's wave-length inside the well becomes comparable to the non-commutative length-scale.Comment: 12 pages, 6 figure

Zulu oral art

Oral tradition? Verbal art? Traditional literature? Performance? The terms used for oral art in South Africa are almost just as varied as the art forms themselves. While these names represent the way academics view their subject matter, they also represent, to some degree, the state of the subject matter. The varied forms of oral tradition in South Africa span the whole spectrum from extinct and forgotten to emergent and unrecognized.Not

I control the idioms : Creativity in Ndebele praise poetry

With reference to the analysis of Ndebele praise poetry that is the subject of this article, "creativity" will refer mainly to two aspects of language use, namely (a) the ability of praise poets to constantly renew well-known formulaic expressions by linguistic adaptation and (b) a more innovative aspect: the coinage of new metaphors, the forte of praise poets in Southern Africa. We will then pose the question as to whether these aspects of creativity are enough to sustain the tradition of praising in Ndebele.Not

Spectrum of the three dimensional fuzzy well

We develop the formalism of quantum mechanics on three dimensional fuzzy space and solve the Schr\"odinger equation for a free particle, finite and infinite fuzzy wells. We show that all results reduce to the appropriate commutative limits. A high energy cut-off is found for the free particle spectrum, which also results in the modification of the high energy dispersion relation. An ultra-violet/infra-red duality is manifest in the free particle spectrum. The finite well also has an upper bound on the possible energy eigenvalues. The phase shifts due to scattering around the finite fuzzy potential well have been calculated

Clinical use of a portable electronic device to measure haematocrit

A small portable device called the blood electrometer (HEM) was developed to assist clinicians to distinguish patients with extreme blood loss from those with normal packed cell volumes. Blood was collected in 5 ml lithium heparin tubes from 80 normal controls and 24 patients in an intensive care unit. BEM and accurate microcentrifugal techniques were compared. Intraclass correlation coefficients between the techniques of r =0,96 and r =0,93 were found in the normal controls and patients respectively. Because the BEM operates on the principle of conductivity, changes in some of the biochemical variables which could influence conductivity were investigated in the patients. Mean plasma total protein and albumin concentrations were lower compared with normal reference ranges. Six of the 24 patients were acidotic and 4 alkalotic. Leucocyte counts obtained randomly from 13 patients were elevated. Changes in measurements which could influence conductivity did not affect the BEM reading. We conclude that the portable BEM could be of great value in circumstances where a fixed power source is not available and rapid haematocrit measurements in a large number of patients are required

Effect of desferrioxamine on reperfusion damage of rat heart mitochondria

Ischaemia of the myocardium leads to necrosis unless oxygen supply is restored but it has only recently been realised that reperfusion is not without danger. The greatest rate ofmyocardial damage, as measured by mitochondrial function, occurred during the first 5 minutes of reperfusion in rat hearts subjected to normothermic ischaemic cardiac arrest. Addition of desferrioxamine to the perfusate after 5 minutes of reperfusion did not reverse the mitochondrial damage. It is therefore concluded that desferrioxamine prevents mitochondrial damage caused by ischaemia-reperlusion but does not reverse the damage already present

Assessing the quality of food served under a South African school feeding scheme: A nutritional analysis

Published ArticleSchool feeding schemes have been implemented in various schools across the globe to improve the nutritional welfare of learners. The purpose of this study was to identify possible nutritional benefits or deficiencies of the foodstuffs served in the South African National School Nutrition Programme in the Free State Province (South Africa). Representative meal samples were collected from randomly selected schools and the nutrient content of meals was determined. The results were measured against nutrient-based standards for an average school lunch for individuals aged 7–10 and 11–18 years. The meals did not meet the nutrient standards for carbohydrate and energy contents for either age group. Protein standards were met by 90% of meals for individuals aged 7–10 years and by 40% for those aged 11–18 years. Only 10% of meals met the standards for calcium and zinc, while 80% and 30% met the iron standards for those aged 7–10 years and 11–18 years, respectively. The lipid and vitamin C contents were within standards. The implementation of proper storage and food preparation procedures may assist in preserving the quality of nutrient

Relativistic mean field formulation of clustering in heavy nuclei

Very little is known about clustering in heavy nuclei and in particular the interaction between the correlated cluster nucleons and remaining core nucleons. Currently the phenomenological Saxon-Woods plus cubic Saxon-Woods core-cluster potential successfully predicts the alpha decay half-life and energy band spectra of a number of heavy nuclei. This model, however, lacks a microscopic understanding of clustering phenomenon in these heavy nuclear systems. A fully relativistic microscopic formalism is presented, which generates the core-cluster potential by means of the McNeil, Ray and Wallace based double folding procedure. The core and cluster baryon densities are calculated by using a relativistic mean field approach. The Lorentz covariant IA1 representation of the nucleon-nucleon interaction is folded with the core and cluster densities. Theoretical predictions of the ground-state decay half-life and positive parity energy band of 212Po are obtained with the relativistic mean field formalism and which are compared to the results from the phenomenological Saxon-Woods plus cubic Saxon-Wood core-cluster potential and microscopic M3Y interaction