Recognition of neotype specimens for species described from the Arnot Pipe, Banke, Namaqualand, South Africa

Important palynological studies were completed by Scholtz (1985) on material from the Arnot Pipe on the farm Banke in Namaqualand, Northern Cape Province. The results comprised a rare record of early Tertiary vegetation in southern Africa. The body of Scholtz’s research consisted of systematic, descriptive palynology including the description of one new genus and fifteen new species. Ongoing research into South Africa’s Tertiary palynology requires that the type specimens from Arnot be used for comparative purposes. However, the microscope slides on which they were founded were not available for examination. Another set of slides, representing two of the seven samples taken at Arnot, was used to search for neotype specimens to replace the missing holotypes. Specimens representing all fifteen new species were found, but were often badly preserved, obscured by debris or trapped between air bubbles as the condition of the decade-old microscope slides had deteriorated. Only specimens in good condition were selected as neotypes, and comprehensively illustrated. Four of Scholtz’s new species were transferred to alternative, more applicable, genera.The Council's Research Committe, University of the Witwatersrand; National Science Foundatio

The effect of nitrite and nitrate concentrations on low F/M filament bulking in nitrogen removal activated sludge systems

Includes bibliography.Filamentous bulking and its associated poor sludge settleability is a considerable problem in South African activated sludge plants, as indicated by the two surveys undertaken on these plants in 1985 and 1988 (Blackbeard et al., 1986, 1988). Amelioration of this problem would enable a greater daily flow and load of wastewater to be treated by these plants. From the surveys it is apparent that bulking in long sludge age activated sludge plants is mainly due to the proliferation of the group of so-called low F/M filaments (as classified by Jenkins et al., 1984). In the course of a 4-year research program investigating specific bulking control methods, Gabb et al. (1989) concluded that the selector effect, which was proposed as a method for controlling low F/M filament bulking, was ineffective. This research also indicated that in fully aerobic systems low F/M bulking was ameliorated, but in intermittently aerated anoxic-aerobic systems low F/M filament bulking was promoted. The research presented in this thesis forms part of a follow-up bulking research program into low F/M bulking which led to the formulation of a bulking hypothesis by Casey et al. (1992b) and focuses on the effect of different anoxic-aerobic conditions and their effect on the concentration of nitrate and nitrite entering the aerobic zone/reactor in single intermittently aerated and multi-reactor nitrification-denitrification systems

Stroke in the young

CITATION: De Villiers, R. V. P., February, E. & De Villiers, M. L. 2003. Stroke in the young. South African Medical Journal, 93(11):836-837.The original publication is available at http://www.samj.org.za[No abstract available]Publisher’s versio

Democracy in schools: are educators ready for teacher leadership?

The aim of this research was to determine educators’ perceptions of and readiness for teacher leadership. A total of 283 educators in the Eden and Central Karoo Education District in the Western Cape participated in the study. The participants included district officials, principals, and members of school management teams, as well as veteran, middle, and novice educators. A series of instruments was used to determine educators’ perspectives, perceptions and readiness for teacher leadership, including the Teacher Leadership Readiness Instrument (TLRI). The results indicated that educators held positive assumptions about teacher leadership. Educators’ preliminary leadership perceptions, assumptions about and readiness for teacher leadership proved that the majority of educators are ready for a more distributed, deep democratic leadership practice in schools. Educators acknowledged the need for continuous professional development in the area of teacher leadership. It was also found that as preliminary leadership perceptions of educators improve or strengthen, readiness for teacher leadership is also likely to improve or strengthen. These findings have significant implications for leadership practices, collaboration, capacity-building and improvement in schools, educators’ self-esteem, motivation and productivity, as well as student outcomes.Keywords: distributed leadership; educators’ assumptions; educators’ perceptions; educators’ readiness; parallel leadership; professional development; teacher leadershi

The palynology of tertiary sediments from a palaeochannel in Namaqualand, South Africa.

Main articleA site in amaqualand, Western Cape Province, has yielded a diverse and well-preserved pa lynoflora. The site consists of a quarry, exposing a palaeochannel containing fluviatile sands, silts and clays with accompanying peat horizons. This paper presents a qualitative account of the pollen and pore assemblages extracted from the peats. Ang iosperms were dominant both in terms of the number of individuals and the recognised types. Identification were made where possible with reference to published illustrations and descriptions. There was a total of 69 palynomorph types, including spores, gymnosperm and angiosperm pollen.Non

To be or not to be: Examining the Role of Language in a Concept of Negation

Negation is a complex, abstract concept, despite the ubiquity of words like “no” and “not” in even young children’s speech. One challenging aspect to words like “no” and “not” is that these words can serve many functions in speech, giving us tools to express an array of concepts such as denial, refusal, and nonexistence. Is there a single concept of “negation” that unites these separate negative functions – and if so, does understanding this concept require the structure of human language? In this paper we present a study demonstrating that adults spontaneously identify a concept of negation in the absence of explicit verbal instructions, even when the exemplars of negation are perceptually varied and represent many different functions of negation. Furthermore, tying up participants’ language ability using verbal shadowing impairs participants’ ability to identify a concept of negation, but does not impair participants’ ability to identify an equally complex control concept (natural kinds). We discuss our findings in light of theories regarding the representation of negation and the relationship between language and thought

First-year Accounting students’ confidence levels during Covid-19: Evidence over a period of two years at a South African university

The Coronavirus Disease (Covid-19) outbreak has caused serious and continuous concerns globally within the higher education sector. One of these is the confidence levels of students to perform specific academic-related tasks. This study explored first-year accounting students’ confidence levels during Covid-19 over a two-year period at a South African university to determine if any associations exist between students’ gender, age, choice of study, language, and method of study funding, compared to confidence level, whilst applying a quantitative research design. Mixed results were obtained. Areas for further research identified include collaboration with other universities, and to expand the scope of the population, to determine the status of students’ confidence levels for different accountancy-related modules during and post-Covid-19. The study will inform and sensitise lecturers, students and academic institutions regarding the confidence levels of students to perform specific academic-related tasks within accounting education and training under Covid-19 conditions

Leaveraging the continuous adjoint method for industrial scale application

One of the fastest growing fields in CFD research is adjoint optimization. Adjoint methods are widely used by people in industry to optimize their products. Drag force minimization of a car, lift force maximization of aeroplanes and minimization of power losses in ducts are some of these optimization problems. The adjoint method provides the sensitivity derivatives of the objective function (drag force etc.) with respect to the design variables (nodal displacement towards the normal direction of the surface). The calculation of the sensitivity derivatives is independent from the number of the design variables which gives the adjoint method a major advantage comparing with the other methods, especially in the problems with large design spaces

The adjoint mehod for automotive optimisation using a sphericity based morpher

A robust workflow for shape optimisation of internal and external flows with application to automotive design is demonstrated in this paper. A gradient based approach is presented, in which the surface sensitivity with respect to the flow variables is computed with the continuous adjoint method. For aerodynamic shape optimisation cases, mesh displacement algorithms are indispensable in order to avoid re-meshing the updated geometry in each optimisation step. Keeping the same mesh topology at every optimisation cycle secures gradient consistency and the possibility to use the previous solution as initial conditions in order to converge the CFD equations faster. Simple mesh displacement algorithms, such as the spring analogy, run into problems under complex surface deformations. Thus a mesh optimisation approach can be proved to be more robust as it copes better with complex elements optimising also the base mesh. In this paper the mesh displacement algorithm is based on sphericity, which quantifies the mesh quality. Solving an extra optimisation problem for the maximisation of the sphericity value, results in the new internal mesh nodes positions. The methodology is heuristic in nature in that it does not consider known numerical quality metrics explicitly. It has shown however to be exceptionally robust and effective allowing the maintenance of high cell quality even during extreme deformation events. The suggested method is applied to automotive test cases of internal and external aerodynamics. In such cases, the use of a robust morpher which preserves geometry features and delays mesh quality deterioration is found to be crucial