Showing papers by "University of South Africa published in 1989"

The Carroll-Green-Schaffer Scaling in Correspondence Analysis: A Theoretical and Empirical Appraisal:

Abstract: In two recent JMR articles, Carroll, Green, and Schaffer have proposed an alternative scaling of the coordinates in the correspondence analysis of a contingency table. This “CGS scaling” is claimed...

Spectroscopic and photometric observations of SN1987A. V - Days 386-616

Abstract: Presentation des observations photometriques et spectroscopiques de SN 1987A effectuees a l'Observatoire Sutherland du SAAO entre 386 et 616 jours apres l'episode de neutrinos de Kamiokande-II

The Draw-a-Man Test: A 50-Year Perspective on Drawings Done by Black South African Children

Abstract: Human figure drawings done by 415 urban black children were compared with the figures of people drawn by children in 1938 and 1950. Though children from five to eight years of age showed no change in performance over the 50-year time-span, there was a significant improvement in the Goodenough scores obtained by contemporary children of school age in comparison with the historical samples. Whilst it is feasible that betterment of the wider social milieu of black people in South Africa may be associated with these changes, no significant relationships between Draw-a-Man scores and socio-economic status could be demonstrated for the older children in the 1988 sample. For this group, test performance showed some relationship with scholastic achievement. The Draw-a-Man test appears to have some validity as a general cognitive measure amongst local black children between the ages of five and eight years. The test seems to be unsuitable for children over eight years of age because, from this age onwards, it unde...

Dynamic boundary conditions for the Navier–Stokes equations

Abstract: When a symmetric rigid body performs a rotation in a fluid, the system of governing equations consists of conservation of linear momentum of the fluid and conservation of angular momentum of the rigid body. Since the torque at the interface involves the drag due to the fluid flow, the conservation of angular momentum may be viewed as a boundary condition for the field equations of fluid motion. These equations at the boundary contain a time derivative and thus are of a dynamic nature. The familiar no-slip condition becomes an additional equation in the system which not only governs the fluid motion, but also the motion of the rigid body. The unknown functions in the system of equations are the velocity and pressure fields of the fluid motion and the angular velocity of the rigid body.In this paper we formulate the physical problem for the case of rotation about an axis of symmetry as an abstract ordinary differential equation in two Banach spaces in which the velocity field is the only unknown. To achieve this, a method for the elimination of the pressure field, which also occurs in the boundary condition, is developed. Existence and uniqueness results for the abstract equation are derived with the aid of the theory of B-evolutions and the associated theory of fractional powers of a closed pair of operators.

Several versions of the integro-differential equation approach to bound systems

Abstract: We find that a single two-variable integro-differential equation, which includes all two-body correlations, produces results for three- and four-body bound systems in good agreement with those obtained with the most accurate methods and also that for sixteen fermions, interacting by means of local Wigner-type potentials our results agree with those obtained with the Variational Monte-Carlo and the Fermi-Hypernetted chain methods. This equation includes a hypercentral potential. When it is set equal to zero it reduces to theS-state projected potential version of the formalism, which for three nucleons is identical to the exact Faddeev equation forS-state projected potentials. We show that the inclusion of the hypercentral component of the two-body local potential, which operates on all orbitals, takes the effect of the higher partial waves largely into account without the need of solving a system of coupled integro-differential equations. We, furthermore, show that by using the Weight-Function Approximation our integro-differential equation is transformed into a simple inhomogeneous differential equation, which becomes accurate forA≲16. The major advantages of our approximate method are, firstly, that unlike the exact Faddeev-Yakubovsky and Alt-Grassberger-Sandhas equations or the Monte-Carlo methods, it does not become rapidly unmanageable, but even simplifies with increasingA and, secondly, the speed and simplicity of our numerical calculations.

Cluster calculations of the Si(111) 7 x 7 dimer-adatom-stacking-fault structure.

Abstract: We have studied the dimer\char21{}adatom\char21{}stacking-fault (DAS) 7\ifmmode\times\else\texttimes\fi{}7 reconstruction on Si(111) using quantum-chemical calculations of large triangular clusters representing the two halves of the surface unit cell (SUC). We calculate the DAS structure to be 0.17 eV per 1\ifmmode\times\else\texttimes\fi{}1 SUC more favorable than the 2\ifmmode\times\else\texttimes\fi{}1 chain reconstruction. It is found that the electronic structure is quite sensitive to vertical displacements of the surface atoms, even though the surface energy remains relatively undisturbed. We associate the phenomenon with the pairing of the rest atoms and the central adatoms which resembles the Jahn-Teller effect. We then show that the effect is important for a realistic model of the DAS reconstruction energetics, which explains the occurrence of 7\ifmmode\times\else\texttimes\fi{}7 reconstruction rather than other odd-by-odd surface patterns. Regarding the bonding configuration, we find (somewhat delocalized) bonds between the adatom and first-layer atoms, and also between these and the second-layer atom directly below the adatom. However, we find there is no bond between the adatom and the second-layer atom. Instead, there is an s-like dangling-bond orbital on the adatom. We expect the adatom backbonds to be weakened single bonds.

The use of a clamp-on plate for forearm fractures.

Abstract: A clamp-on plate has been developed to stabilize long-bone diaphyseal fractures. Its design is entirely different from conventional screw-secured plates. Minimal soft tissue, especially periosteal, dissection is required for application. Since there is no intramedullary encroachment, no further damage is done to the endosteal blood supply. One hundred seventy-one fractures of the radius and/or ulna were followed for at least 6 months. There were no nonunions. The average time to union was 12.3 weeks, compared to 21.4 weeks for similarly selected fractures of the radius and/or ulna treated during the same time framework by conventional screw-secured plating methods. The fact that union is reliable and can be achieved earlier than with conventional screw-secured plates supports the author's contention that sparing of the blood supply to the fracture and thus, the biological integrity of fracture healing play a parallel role along with biomechanical stability in achieving fracture union.

Household Density, Family Size and the Growth and Development of Black Children — A Cross-Sectional Study from Infancy to Middle Childhood:

Abstract: The relationship between household density, family size (number of children) and the physical growth and psychological development of more than 1000 black children between two months and 10 years of age was examined. The results indicated that household density was not linearly related to family size or socioeconomic status, as the housing shortage forces most families to share accommodation. Higher household density was found to be related to smaller growth among children from the beginning of their third year of life, and both higher household density and increased family size were found to be related to lower scores on the developmental measures from six years of age onwards. While household density levels were found to remain constant across the age span represented by the sample, household and family structures underwent several changes, including increased nuclearization. In general, household density measures did not yield data relating to important changes in the interpersonal environment of growi...

Invisible barriers: Attitudes toward women in South Africa

Abstract: South African women are playing an increasingly important role in public life. However, social trends show that gender equity has not been attained. Barriers to the full realization of female potential are intemal and extemal. Attitudes towards women within the particular context of South African society are examined. Sex-role ideology, moulded by the patriarchal character of South African society and concomitant authoritarian norms, is investigated. Attention is given to the vulnerable position of black women whose estate is shaped by a dual discrimination of race and sex. The presence of black domestic workers affects relations between white and black women and impedes the amelioration of conjugal sex roles among Whites. In particular, the position of middle-class white women is described. The effect of religious views on sex roles is discussed as well as the female image propagated by the media. Attitudes towards women within the familial power structure reveal a slowly increasing egalitariani...

Eerwaarde Archibald Lamont : kampvegter vir die minderbevoorregte

Abstract: The Reverend Archibald Lamont -Champion of the Underdog. The Reverend Archibald Lamont dedicated his whole life to improving the position of the underdog, irrespective of his religion, class or race. To him people were merely people and therefore during his term as city councillor he campaigned to improve the position of Durban's underdogs: the white labourers, the Indians and the blacks. Lamont considered racial discrimination against the Indians and blacks especially unacceptable since it clashed with his religious beliefs and his trust in British Justice, a view which did not endear him to most of the Durban whites, who regarded him as too liberal, and which resulted in his defeat during the provincial and parliamentary elections of 1927 and 1929. Lamont's election in 1929 as Durban's mayor therefore came as a surprise. In fact, his election was part of the city council's campaign to end an effective black boycott of the municipal beer halls. This boycott was a result of the blacks' dissatisfaction with the harsh municipal administration. By electing a more liberal person, such as Lamont, as mayor it was hoped to give credibility to the municipality's attempt to end the boycott by following an ambiguous policy of reform and oppression. However, instead of being a mere ceremonial figure, Lamont had his own ideas on reform and justice and during his three years as mayor he succeeded to some extent in improving the position of the blacks. This also brought him into conflict with the city council, The Natal Mercury, and most of the Durban whites, who viewed his efforts on behalf of the blacks with suspicion. Eventually Lamont was defeated in his bid for a fourth term as mayor and the city council subsequently took a more conservative stand on racial issues. In recognition of his efforts to improve the circumstances of the blacks, the new Umlazi black township was named Lamont township (today Lamontville) on black demand. Lamont also received recognition from the white workers of Durban who, as a result of his efforts to improve their economic position, elected him as a member of the provincial council for Greyville in 1932.

Toward the Prediction and Stimulation of Creativity

Abstract: In this article, various conceptions of creativity are briefly considered, the assumption that findings relating to one type of creativity may be generalized to another is questioned, a pattern of characteristics and experiences that are typical of eminent productive creators is focused on, and some of the implications for the prediction and promotion of productive creativity are pointed out. In combination, consistent findings of various types of past research seem to form a pattern. They suggest that three factors, acting in concert, contribute to the development of the persistent motivation that is typical of productive creators: (a) values relating to intellectual achievement; (b) precocious development of basic ability in a relevant domain; and (c) stress. These influences apparently cause a tendency to engage in independent intellectual pursuits which offer palliation, afford a sense of control, build a wider repertoire of skill and knowledge than is usually gained through adherence to a curriculum,...

Postmodernist narrative strategies in Foe

Abstract: Summary It is argued in this paper that Coetzee's notion of narrativity necessitates an analysis of the interarticulation between contemporary theoretical discourses and narrative practice. Since calculated construction seems to inform his re‐writing and re‐contextualization of romantic tales of adventure, Genette's structuralist model is used as a framework for tracing Coetzee's unique exploitation of postmodernist narrative strategies via the segmentation of his text into four different parts.

What Do We Do before We Do Theory

Abstract: Against the background of a ‘diagnosis’ of present-day mainstream psychological enterprise, the author explores in which way the application of the method of logico-conceptual critique may enhance the development of theory in psychology. Logico-conceptual critique is described as an heuristic device aimed at the detection and explication of logical tensions/defects/fallacies in psychological theories. It is stressed that the method necessitates the employment of the conceptual schemes of common-sense in terms of which psychological ‘subjects’ or ‘testees’ comprehend their real-life contexts. To apply the method, the author selected a particular research area (concept formation) and concentrated on theoretical positions emanating from three psychological metaphors, namely, man: the behaving machine; man: the mediatory ‘agent’ in the machine; and man: the information processor. Various logico-conceptual weaknesses in each of these positions are pointed out. It is concluded that logico-conceptual critique is...

The Free State Floods: A Case Study

Abstract: This is an exploratory study of the stress experiences of 20 flood victims in the Bloemfontein area. Measures consisted of demographic variables, Rotter's Locus of Control scale, Horowitz's Impact ...

Aspects of oral art and the genesis of Southern-Sotho literature: 1833–1863

Abstract: With interest in the literary history of Southern Africa in an upward phase at the moment, it is being realized more and more that adequate source studies, especially on the early days of the literatures, are necessary. The development of first sources may thus contribute to explaining some of the circumstances in which the literatures began, the course(s) they took, and also to indicating which facets of the oral legacy served as the fountain-head of the new era. In this article the very first sources on the literature in Southern Sotho, as well as the first texts, are discussed in terms of their (sometimes paradoxical) significance to the history of the literature.

Spatial pattern and variability of soils in a granite landscape, north-east of Nelspruit

Abstract: Morphological and selected chemical and granulometric properties of eleven soil profiles occurring on five hillslope sites (midslope, upper footslope, mid-footslope, lower footslope and valley bottom) were determined in order to evaluate the spatial pattern and variability of soils in a granitic area north-east of Nelspruit. A transect design was employed to compare the variance of selected soil properties within and between hillslope positions. Although a drainage-toposequence had developed in the colluvial deposits on the footslope, this soil pattern was interrupted in mid-footslope by sands of the Longlands form encountered between sands of the Avalon form. Meso-scale deflections of the bedrock floor in the form of hillslope terraces were presumably responsible for this variation in soil pattern. To study soil variability statistically, a two-stage nested design and an analysis of variance were employed. Although few significant results were obtained, certain tendencies were evident which pointed to a ...

Locus standi in environmental law

Abstract: In conclusion, one must applaud the many positive elements encorporated in the Draft Bill on Environment Conservation 1987. In some respects one may notice certain similarities with the NEPA of the USA, for example, a distinct national environment policy (the first of its kind) in clause 3, the provisions regarding environmental impact assessments or reports (EIA) in clauses 22, 23 and 26, and the promotion and appreciation of public participation in environmental affairs, for example in clauses 2,5,6, 13, 15, 17,22 and 26. Although the Bill does not make provision for judicial control by the civil courts, a possibility exits that an additional section will be included in the final Act to regulate some form of judicial review by the courts.

Pseudo-classical phase space description of the relativistic electron

Abstract: Several versions exist of pseudo-classical models of the electron using Grassmann variables. Most of these require additional constraints on the variables, and it is these which, when quantized, lead to Dirac's equation. In addition, the Grassmann variables do not have physical interpretations. In this article a model is constructed which does not require constraints and in which the Grassmann variables can be interpreted as observables. Dirac's equation is obtained directly from quantization.

Degree uniform graphs

Abstract: In such a case, we also refer to G as an n-degree uniform graph. If G is a regular graph of order p, then G is a p-degree uniform graph. Some nonregular degree uniform graphs are shown in FIGURE 1. The graph G , is a 2-degree uniform graph with degree-set gG, = {2, 3}, G , is a 2-degree uniform graph with degree-set G@G2 = { 1, 2, 3}, and G, is a 4-degree uniform graph with gG3 = (2, 4). In 1936 Konig [S] showed that if H is a graph with maximum degree d, then there exists a d-regular graph G such that H is an induced subgraph of G. In 1963

The registered distance of the celestial sphere: some historical cross-cultural data.

Abstract: Estimates of the diameters of the sun and moon expressed in centimetres have been reported by several authors in the past. These estimates imply that the sizes of the sun and moon are perceived as if these bodies are only some tens of metres distant. In this study five units of length that were used by ancient astronomers to estimate arcs on the celestial sphere were investigated. The purpose was to determine whether the lengths and angles represented by these units imply a specific registered distance of the star sphere. The sizes of the Babylonian cubit, Arab fitr and shibr, Greek eclipse digit, and Chinese chang support the conclusion that the registered distance of the stars was about 10 to 40 metres in these four cultures over the last two millennia.