Showing items 201 - 220 of 233

Your selections:

The removal and recovery of toxic and valuable metals from aqueous solutions by the yeast Saccharomyces cerevisiae

  • Authors: Wilhelmi, Brendan Shane
  • Date: 1998
  • Subjects: Saccharomyces cerevisiae , Yeast fungi -- Biotechnology , Sewage -- Purification -- Heavy metals removal
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4002 , http://hdl.handle.net/10962/d1004062 , Saccharomyces cerevisiae , Yeast fungi -- Biotechnology , Sewage -- Purification -- Heavy metals removal
  • Description: This project considered the use of the yeast Saccharomyces cerevisiae as a biosorbent for the removal and recovery of a range of metals from contaminated waters. S. cerevisiae, as a biosorbent, has the potential to provide a cost effective, selective and highly efficient purification system. Initial studies focused on metal accumulation by an immobilized baker's S. cerevisiae biosorbent. The parameters affecting metal uptake were investigated, these included metal concentration, time and solution pH. Metal uptake was rapid. Gold and cobalt reached saturation within 5 min of contact with the biosorbent in batch reactors. Copper, zinc, nickel, cadmium and chromium reached saturation within 30 min of contact. Metal accumulation was pH dependent and was generally unaffected at a solution pH ≥ 4, and was substantially decreased at pH ≤ 2. The exception was gold which was preferentially accumulated at a solution pH of 2. The immobilized baker's yeast accumulated metals with maximum binding capacities in the order of gold > cadmium > cobalt > zinc > copper > chromium > nickel. A rapid method to assess metal recovery was developed. Bioaccumulated metal was efficiently recovered using dilute mineral acids. Copper recovery of ≥ 80 % was achieved by decreasing the solution pH of the reaction mixture to 2 with the addition of nominal quantities of HCl, H₂SO₄ or RNO₃. Adsorption-desorption over 8 cycles had no apparent adverse effect on metal uptake or recovery in batch reactors. Transmission electron microscopy showed no evidence of damage to cells used in copper adsorption-desorption investigations. Biosorption columns were investigated as bioreactors due to their application potential. The metals investigated were effectively removed from solution. At a saturation threshold, metal uptake declined rapidly. Most metals investigated were desorbed from the columns by eluting with 0.1 M HCl. Initially recoveries of copper, cobalt and cadmium were as high as 100%. Desorbed copper, zinc, cadmium, nickel and cobalt were concentrated in 10 to 15 ml of eluent, representing up to a 40 fold decrease in solution volume. Cadmium, nickel and zinc uptake increased with the second application to the columns. Initial accumulation of gold and chromium was 42.2 μmol/g and 28.6 μmol/g, however, due to the low recoveries of these two metals, a second application was not investigated. Copper was applied to a single column for 8 consecutive adsorption-desorption cycles. Uptake increased from an initial 31.3 μmol/g to 47.8 μmol/g at cycle 7. The potential for selective metal recovery was demonstrated using two biosorption columns in series. Copper was accumulated and recovered most efficiently. Zinc, cobalt and cadmium were displaced to the second column. Copper bound preferentially to zinc at a ratio of 6:1. Copper bound preferentially to cobalt at a ratio of 4:1. Cadmium was only displaced at a ratio of 2:1. The successful transfer of the bioremediation technology from the laboratory to an industrial application has yet to be realized. Bioremediation of a Plaatjiesvlei Black Mountain mine effluent, which contained copper, zinc, lead and iron, was investigated in this project. The removal of the metals was most effective at pH 4. A combined strategy of pH adjustment and bioremediation using immobilized S. cerevisiae decreased the copper concentration by 92.5%, lead was decreased by 90% and zinc was decreased by 60%. Iron was mostly precipitated from solution at pH ≥ 4. An ageing pond at the mine with conditions such as; pH, water volume and metal concentration, which were more conducive to biological treatment was subsequently identified. The investigation indicated a possible application of the biomass as a supplement to chemical remediation. The metal removal capability of a waste brewer's yeast was subsequently investigated. A yeast conditioning step increased metal uptake up to 100% and enhanced reproducibility. Metal removal from solution was rapid and pH dependent. The metals were efficiently removed from solution at pH ≥ 4. Uptake was substantially inhibited at pH ≤ 3. The waste brewer's yeast accumulated metals with maximum binding capacities in the order of copper (25.4 μmol/g) > lead (19.4 μmol/g) > iron (15.6 μmol/g) > zinc (12.5 μmol/g). No correlation between cell physiology and metal uptake was observed. Uptake of the four metals was confirmed by energy dispersive X-ray microanalysis. The interference of lead, zinc and iron on copper uptake by the waste brewer's yeast, and the interference of copper on the uptake of lead, zinc and iron was investigated. Maximum copper uptake was not decreased in the presence of lead. The Bmax remained constant at approximately 25 μmol/g. The dissociation constants increased with increasing lead concentrations. Lead bioaccumulation was significantly decreased in the presence of copper. The type of inhibition was dependent on the initial copper concentrations. Zinc had a slight synergistic effect on copper uptake. The copper Bmax increased from 30.8 μmol/g in a single-ion system to 34.5 μmol/g in the presence of 200 μmol/l of zinc. Zinc uptake was severely inhibited in the presence of copper. The maximum uptake and dissociation constant values were decreased in the presence of copper, which suggested an uncompetitive inhibition. The affinity of copper was substantially higher than zinc. The presence of higher levels of copper than zinc in the yeast cells was confirmed by energy dispersive microanalysis. Copper uptake was decreased in the presence of iron, with the copper Bmax being decreased from 25.4 μmol/g in a single-ion system to 20.1 μmol/g in the presence of 200 μmol/l iron. Iron Bmax values remained constant at 16.0 μmol/g. Combined biosorption and EDXA results suggested the iron bound at a higher affinity than copper to the cell wall. Total copper removal was higher as larger quantities of copper were deposited in the cell cytoplasm. Metal removal from the Plaatjiesvlei effluent by free cell suspensions of the waste brewer's yeast was satisfactory. Copper levels were decreased by 96%, iron by 42%, lead 25% and zinc 2%. Waste brewer's yeast is a cheap source of biomass in South Africa, and could potentially provide the basis for the development of an innovative purification system for metal-contaminated waters.
  • Full Text:
  • Date Issued: 1998

The requirements for accurate analysis of pharmaceutical research at South African Universities

  • Authors: Haigh, John M , Smith, Eric W
  • Date: 1998
  • Language: English
  • Type: text , Article
  • Identifier: vital:6367 , http://hdl.handle.net/10962/d1006067
  • Description: International Pharmaceutical Abstracts is a valuable database for pharmaceutical research, although the multisiciplinary nature of this field implies that the database should only be the starting point of a search. This database is totally inappropriate for comparing outputs of individual pharmacy teaching institutions.
  • Full Text:
  • Date Issued: 1998

The shuttle effect : the development of a model for the prediction of variability in cognitive test performance across the adult life span

  • Authors: Jordan, Ann B
  • Date: 1998
  • Subjects: Cognition -- Age factors Aging -- Psychological aspects Cognition in old age Human information processing -- Age factors Older people -- Psychology
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:3191 , http://hdl.handle.net/10962/d1008556
  • Description: The aim of this thesis was to investigate inter-individual variability on cognitive task performance in normal older adults. In a review of the cognitive aging literature, the implications of a differential perspective were drawn out in order to establish a theoretical and methodological basis for an investigation into variability. A number of regularly occurring patterns, identified on the basis of available reports in the literature, were used to develop a model of variability (the shuttle model). The empirically-based model was located broadly within a neuropsychological framework, and derived explanatory power from the tenets of brain reserve capacity (BRC) theory. It served to describe the bulge in interindividual variability due to aging (the shuttle bulge), and the shifting occurrence of the bulge in relation to the age axis due to cohort and task-related influences (the shuttle shift). A two phase research study was conducted in order to test hypotheses derived from the model. Phase 1 comprised between-groups analyses of normative data covering a broad range of neuropsychological tests in the domains of attention, memory, language, visual and hand motor skills, in order to examine the progression of variability effects across the adult age range. Phase 2 constituted between and within-groups analyses of normative data from a more limited number of neuropsychological tests. It included the examination of raw score distributions and the characteristics of outliers, and was undertaken to explore more closely the nature of the variability phenomena detected in the first phase of the analysis. Taken together, the results of both phases of the investigation revealed statistically significant variability effects in support of the shuttle model. There was a consistent pattern of increased variability in association with older age regardless of functional modality; frequently, in association with later old age, there was also a subsequent decrease in variability (the shuttle bulge). The age of onset of the initial increase in variability occurred earlier or later (the shuttle shift) as a function of four factors: education, gender, task challenge and age-sensitivity of task. The finding of an earlier onset of variability effects for low education, male gender, high task challenge and high age-sensitivity of task was interpreted in terms of BRC threshold theory. The clinical and social implications of the outcome were discussed with special emphasis on the need for a differential perspective on aging, as a complement to the prevailing normative tradition. It was concluded that the shuttle model has considerable heuristic value. It presents an integrative framework for understanding existing variability data and provides clear indications for future research.
  • Full Text:
  • Date Issued: 1998

The theoretical and empirical analysis of trade integration among unequal partners : implications for the Southern African Development Community

  • Authors: Cattaneo, Nicolette Sylvie
  • Date: 1998
  • Subjects: Southern African Development Community , Customs unions , Africa, Southern -- Foreign economic relations , Africa, Southern -- Economic integration
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:1008 , http://hdl.handle.net/10962/d1002743 , Southern African Development Community , Customs unions , Africa, Southern -- Foreign economic relations , Africa, Southern -- Economic integration
  • Description: The re-acceptance of South Africa into the international community has cleared the path for the closer integration of South Africa with its neighbours in a broader southern African regional union. In particular, the countries of the Southern African Development Community {SADC), which South Africa joined in August 1994, have committed themselves to the formation of a free trade area (FTA) over an eight-year period. The most likely impediment to this process is the perception of a highly unequal distribution of the economic gains and losses of such an arrangement. This reflects the particular context of SADC: one of a comparatively undeveloped region, dominated by a relatively large, more industrially advanced country, which is itself small by international standards. The essential question with which this study is concerned, therefore, is whether, despite the existing inequalities in the region, a FTA among SADC members could be mutually beneficial to South Africa and its partners. The thesis applies orthodox and new trade theory to the analysis of economic integration among unequal partners. Using the theoretical analysis, and with reference to empirical studies of such experience elsewhere in the world, it attempts to provide an assessment of the existing body of literature on the possible effects of a SADC FTA. In the light of this discussion, and from its own preliminary empirical analysis of the possible pattern of inter-sectoral versus intra-sectoral specialisation which may result on union, the study suggests ways in which a fuller evaluation of the welfare implications of a southern African FTA may be achieved. The thesis argues that the orthodox theory based on perfect competition provides an insufficient framework for the analysis of the likely effects of a SADC FT A. It finds that, firstly, in an alternative analytical framework which retains the assumption of perfect competition, there may be other criteria for judging the success of a regional union that are neglected by orthodoxy, particularly in the case of developing countries. Secondly, the new trade theory based on imperfect competition and product differentiation provides useful insights into the possible effects of a regional union among countries at unequal levels of development. The formal extension of this body of literature to the theory of economic integration is clearly called for. It is found, however, that neither orthodox customs union theory, nor its suggested alternatives and extensions, enable one to conclude, a priori, that the formation of a FTA in the southern African region could not be beneficial to both South Africa and its smaller partners. Further, the present empirical studies on SADC do not take account of the full range of factors necessary for a complete welfare assessment of the possible effects. Since the outcome of integration depends on the empirical circumstances of the particular case, and since the information necessary for a comprehensive welfare evaluation is not currently available, the study concludes that the countries of the region have committed themselves to a FTA without any definite knowledge of its likely effects.
  • Full Text:
  • Date Issued: 1998

The third Marion Island oceanographic study (MIOS III) conducted during April and May 1998

  • Authors: Froneman, Pierre William , Ansorge, Isabelle J
  • Date: 1998
  • Language: English
  • Type: Article
  • Identifier: vital:6937 , http://hdl.handle.net/10962/d1011959
  • Description: Focuses on the third Marion Island Oceanographic Study (MIOS III). Objectives of the study; Details on the results; Conclusions.
  • Full Text: false
  • Date Issued: 1998

The Tongan maritime expansion: A case in the evolutionary ecology of social complexity

  • Authors: Shankar, Aswani , Graves, Michael
  • Date: 1998
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/440025 , vital:73729
  • Description: The evolution of the Tongan maritime empire, involving both the development of social complexity and geographic expansion through conquest and trading, are examined by means of evolutionary ecology. This Darwinian evolutionary framework provides the mechanism and identifies the environmental structure, processes, and behavioral strategies by which to account for the geographic and temporal pattern of change in Tonga and related islands. Both ethnohistorical and archaeological data are employed in this analysis, showing how both may reveal overlapping aspects of historical change. The results of this research highlight the importance not only of competition but also of cooperative strategies in the evolution of social complexity and the process of geographic expansion. Key to explaining the evolution of Tongan social complexity are the productive but uncertain environment of Tongatapu, the location of Tongatapu in relation to other islands and prevailing winds, the small landmass of the island, the relatively early integration of the island into a single polity, the creation of collateral ruling lineages, the appropriation of voyaging technology to redirect competition from within Tongatapu to other islands through colonization, aggression, staple and wealth goods trade, and the exchange of spouses.
  • Full Text:
  • Date Issued: 1998

The use of optimal foraging theory to assess the fishing strategies of Pacific Island artisanal fishers: A methodological review

  • Authors: Shankar, Aswani
  • Date: 1998
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/440038 , vital:73730
  • Description: Artisanal fisheries play a major role in the social, cultural, and economic life of most Pacific Islanders, particularly in rural communities where people are highly dependent on marine resources for subsistence and commercial purposes. Yet, marine resources are being threatened by pressure from exploding human populations and the increasing commercialisation of the subsistence fishery—circumstances which are now forcing researchers to find novel ways to examine issues of coastal management and marine resource conservation. Among the most recent approaches to coastal management has been to study marine ecological processes in conjunction with those of the contiguous shoreline and upland habitats, or what has been termed Integrated Coastal Zone Management (ICZM). From the standpoint of maritime anthropology, any comprehensive study of the integration of marine and terrestrial biotic components requires the parallel consideration of human activities, including existing property regimes, resource access and distribution rules, and resource exploitation strategies. Although numerous studies have concentrated on the social aspects of Pacific Island artisanal fisheries (eg Johannes, 1981; Hviding, 1996; Lieber, 1994), few have dealt explicitly with the micro-ecology of daily humanmarine interactions (see Aswani, 1997; Bird and Bird, 1997). Such neglect has hampered attempts to fully integrate studies of environmental coastal processes with those of human activities. In this paper, I examine the utility of optimal foraging theory and its methodology, as applied to the study of Pacific Island artisanal fishers. The inclusion of foraging theory can contribute to building a clearer anthropological model to describe the relationship between human foraging and fishery management.
  • Full Text:
  • Date Issued: 1998

The use of supersaturated solutions for the percutaneous delivery of rooperol tetra-acetate

  • Authors: Pefile, S C , Haigh, John M , Smith, Eric W
  • Date: 1998
  • Language: English
  • Type: Conference paper , text
  • Identifier: vital:6340 , http://hdl.handle.net/10962/d1006537
  • Description: A major problem encountered in the transdermal delivery of drugs is the effectiveness of the barrier system imposed by the stratum corneum.To overcome tbe resistance of the skin to the ingress of exogenous chemicals, numerous innovative techniques requiring complex delivery systems have been studied. Many of these systems attempt to alter the barrier potential by the use of enhancer technology. Supersaturation, on the other hand, is a simple and economical technique which is not intended to modify the physical structure or the chemical composition of the stratum corneum, yet may effectively deliver a markedly greater mass of drug to the skin than that achieved by the use of conventional, saturated solutions. Supersaturated systems make use of the elevated thermodynamic activity of the permeant in the delivery vehicle, which results in higher flux rates across the contacting membrane by increasing the concentration gradient. The present study investigated the potential for using supersaturation techniques to transdermally deliver rooperol tetra-acetate (RTA), a lipophilic, cytotoxic agent with potential for use in the treatment of solar keratosis. The diffusion characteristics of the drug from a 60% propylene glycol/water supersaturated solution across silicone membrane and full thickness rat skin were studied using Franz diffusion cells. A comparison was made of the drug diffusion rates from a saturated system and from supersaturated systems prepared with and without an antinucleating agent.
  • Full Text:
  • Date Issued: 1998

The wreck of the Dutch man o' war, Amsterdam, in December 1817 on the Eastern Cape coast of Southern Africa: an elucidation of the literary and material remains with an annotated translation of the Journal of Captain Hermanus Hofmeijer (1814-1818)

  • Authors: Bennie, Jennifer Shirley
  • Date: 1998
  • Subjects: Amsterdam (Steamship) , Shipwrecks -- South Africa , Underwater archaeology , Nederlandsche Oost-Indische Compagnie , Hofmeijer, Hermanus, 1721-1805--Diaries , Voyages and travels -- History -- 18th century
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2533 , http://hdl.handle.net/10962/d1002385 , Amsterdam (Steamship) , Shipwrecks -- South Africa , Underwater archaeology , Nederlandsche Oost-Indische Compagnie , Hofmeijer, Hermanus, 1721-1805--Diaries , Voyages and travels -- History -- 18th century
  • Description: This study endeavours to elucidate the journal of Captain Hermanus Hofmeijer of the Dutch man 0' war, Amsterdam, which has been transcribed from the original script, translated from Dutch into English and interpreted from a contemporary viewpoint. It offers an opportunity to evaluate a unique primary historical document which records an important historical event. An attempt has been made to contextualise the incident in the light of the early history of the Dutch people. The contribution of the Dutch East India Company (VaC) to the trade and commerce of the Netherlands during the 17th and 18th centuries has been assessed together with the shipbuilding techniques that served to make the Dutch a major seafaring nation. The significance of Texel and Nieuwediep has been examined and the sea route and navigational instruments placed in perspective. The voyage has been analysed in some detail. The background of Captain Hermanus Hofmeijer has proved especially interesting. Although he pursued his career with the Dutch Navy, he was born and spent his early years in Cape Town, South Africa. The time spent by the Amsterdam in Batavia, Samaraog and Sourabaya gives an insight into the Dutch possessions overseas. The return voyage, storms and ultimate grounding are of special interest as Hofmeijer records the journey and events on a daily basis. The impact and significance of 217 extra people in the Eastern Cape area did not go unnoticed, and although the event was not well documented, an attempt at some contextualisation has been made. Finally a short overview of maritime archaeology in South Africa and its significance as a relatively new discipline has been included. The study of the material remains of the wreck of the Amsterdam has resulted in a new understanding of wooden ships built in the early 19th century.
  • Full Text:
  • Date Issued: 1998

Thematic integrity in filmic versions of E.M. Forster's novels

  • Authors: Hayes, Kalmia Joy
  • Date: 1998
  • Subjects: Forster, E. M. (Edward Morgan), 1879-1970. Passage to India , Forster, E. M. (Edward Morgan), 1879-1978. Where Angels Fear To Tread , Forster, E. M. (Edward Morgan), 1879-1978. Howards End , Sturridge, Charles , Merchant Ivory Productions , Lean, David, 1908-1991 , Film adaptations , Motion pictures -- Plots, themes, etc
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2218 , http://hdl.handle.net/10962/d1002261 , Forster, E. M. (Edward Morgan), 1879-1970. Passage to India , Forster, E. M. (Edward Morgan), 1879-1978. Where Angels Fear To Tread , Forster, E. M. (Edward Morgan), 1879-1978. Howards End , Sturridge, Charles , Merchant Ivory Productions , Lean, David, 1908-1991 , Film adaptations , Motion pictures -- Plots, themes, etc
  • Description: This study discusses the extent to which Charles Sturridge's Where Angels Fear to Tread, Merchant Ivory's Howards End, and David Lean's A Passage to India have aimed at, and succeeded in, exploring the thematic concerns of E.M. Forster's novels. A brief introductory chapter explains the motivation behind this research, and the choice of critical methodologies used. It concludes with an outline of some of the problems confronting film-makers wishing to explore the concerns of novels. The first chapter, which is devoted to Where Angels Fear to Tread, reveals that while Sturridge is "faithful" to Forster's novel at a superficial level, basing most of his scenes on, and taking most of his dialogue directly from, the text, he does not explore Forster's themes. The facility with which film tells stories proves to be a treacherous trap for Sturridge. His version of Where Angels Fear to Tread is totally vacuous because he failed to develop anything beyond the story -- Forster's "tapeworm" of time (Aspects of the NoyeI41). The causality that Forster calls plot seemed beyond Sturridge's comprehension, leaving his film little more than an endless progression of "and then[s]" (Forster, Aspects 87). Characters are not given their full weight; symbols and leitmotifs are overlooked; the allegorical elements he did recognize, he failed to understand, and thus misplaced, so that the epiphanic moments of the novel are lost. There is no possibility of thematic concerns emerging from a film in which plot, characterization, symbol and rhythm are ignored. Sturridge's apparent inability to understand his source is in stark contrast to Merchant Ivory's sensitivity to Howards End, and their evident familiarity with literary criticism on the work. Chapter two explores the way in which their adaptation smooths out putative flaws in characterization and plot, and uses filmic rhythm and camera work to suggest comments made by the novel's narrator. Almost wholly successful in developing the novel's themes, Merchant Ivory's Howards End does not, however, successfully explore the spiritual dimensions of Forster's novel. Film is a medium capable of great subtlety, but its strength lies in its ability to capture the seen; the unseen tends to evade its grasp. It is in dealing with the unseen that Lean's A Passage to India misses greatness, for in virtually every other respect his version of Forster's masterpiece is superb. Chapter three explores Lean's creative and flexible approach to adaptation, his acute sensitivity to the differing demands of film and novel, and his confident technical mastery. It also explores, however, the emptiness at the heart of his film, an emptiness that is the result of his trivialization of the spiritual concerns of Forster's novel.
  • Full Text:
  • Date Issued: 1998

Title not specified

Title not specified

Title unknown

Tolerance as an ethical issue with special reference to South Africa

  • Authors: Mnyaka, Mluleki Michael
  • Date: 1998
  • Subjects: Religious tolerance , Toleration , South Africa -- Constitution
  • Language: English
  • Type: Thesis , Masters , MTh
  • Identifier: vital:1312 , http://hdl.handle.net/10962/d1020852
  • Description: From Introduction: It was a feature of South African political life to have senseless and continued political violence especially in areas such as KwaZulu Natal and Gauteng., There were certain places that were demarcated as "no-go areas" in other parts of the country for political rivals* This research has been directed by the cries of many South Africans pleading for political tolerance. Tolerance was a term used by both politicians and ordinary people alike and therefore open to misuse and various interpretations. As a term it was therefore without adequate clarification on its meaning. It is an attempt of this study to clarify and promote this value of tolerance. In Chapter One, the value of tolerance is examined. It is described as putting up with what is disliked or disapproved for the sake of others. But it is deliberate and is therefore a virtue. Positive attitudes, motives and power are central to tolerance. For tolerance to be sustained, solid foundations such as education, respect for others and their freedoms, democracy, justice, stability and reciprocity are to be laid. A light is also being shed on the limits of this virtue. Considerations and circumstances which need to be taken when deciding on each an action are the very motives and conditions for tolerance. This further makes the issue of tolerance to be complex. Church history shows that tolerance does not come naturally. It is a difficulty because of certain principles that are at stake. When viewed from the twentieth century perspective many of Church history's periods were of intolerance because the church had power. Tolerance was an exception, a plea of those without power. South Africa has to unlearn much of intolerance because of the past that militated against tolerance. Fortunately tolerance is now being firmly entrenched as law. Even though it is so, the tension of being tolerant and intolerant still exists especially in the whole area of abortion. Let us examine why tolerance is such a complex issue and a virtue to be promoted.
  • Full Text:
  • Date Issued: 1998

Transformational leadership and organisational effectiveness in the administration of cricket in South Africa

  • Authors: Ristow, Adrian
  • Date: 1998
  • Subjects: Cricket--South Africa , Cricket -- South Africa -- Management , Sports administration -- South Africa
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: vital:1182 , http://hdl.handle.net/10962/d1002799 , Cricket--South Africa , Cricket -- South Africa -- Management , Sports administration -- South Africa
  • Description: After years of isolation from the international sporting arena, South African sports teams have recently achieved much success. This study is concerned specifically with managing for organisational effectiveness in South African cricket. According to the theory of transformational leadership, there should be a positive relationship between this style of leadership and organisational effectiveness. The Multifactor Leadership Questionnaire was used to collect information about leadership while data for organisational effectiveness, the dependent variable, was collected using the Effectiveness Survey for Cricket Administration. Most of the results regarding the relationship of the transformational leadership factors and organisational effectiveness were significant. On the other hand, most of the results regarding the relationship of the transactional leadership factors and organisational effectiveness were not significant. The overall results provide general support of the relevance of the transformational leadership theory in the context of cricket administration in South Africa. The results also support Bass's (1990b) argument of the universal application of the transformational leadership theory.
  • Full Text:
  • Date Issued: 1998

Tropical corticosteroid bioequivalence testing comparison of chromameter and visual data

  • Authors: Demana, Patrick Hulisani
  • Date: 1998
  • Subjects: Dermatopharmacology , Dermatologic agents , Skin absorption
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:3755 , http://hdl.handle.net/10962/d1003233 , Dermatopharmacology , Dermatologic agents , Skin absorption
  • Description: The major criticism of the human skin blanching assay is the subjective nature of grading the response. Recently the American FDA released a Guidance document for topical corticosteroid bioequi valence testing. The guidelines require the use of a chromameter as a reliable method to estimate skin blanching. The purpose of this study was to evaluate the recommendations of this document for appropriateness by comparing visual and chromameter data. The visually-assessed blanching assay methodology routinely practised in our laboratories was modified to comply with the specifications of the Guidance. The preliminary trial indicated that the training period that is required for a novice to be classified as an experienced observer is not a major problem. The major trend that emerged from the pilot study was that visual assessment was better than the chromameter. Longer dose durations were found to be more discriminatory than shorter durations. The visual data were best described by the sigmoid Emax model and the chromameter data were best described by the simple Emax model. The pivotal results indicated that the D2/Dj criterion to determine sample size of "acceptable blanchers" produced only few subjects suggesting that the validity of this criterion requires extensive investigations. The estimates of the Locke's confidence interval method were simiJar to those for the general simple formula. However, due to undefined parameters of the Locke's method in the Guidance, the validity of the Locke's method requires evaluation. The chromameter b-scale parameter was the least sensitive in estimating skin blanching whereas the a- and L-scale parameters produced similar results. Poor correlation between visual and chromameter was noted indicating that the visual method is still the best method.
  • Full Text:
  • Date Issued: 1998

Tsiki

Types of case study work : a conceptual framework for case-based research

  • Authors: Edwards, David J A
  • Date: 1998
  • Language: English
  • Type: Article
  • Identifier: vital:6240 , http://hdl.handle.net/10962/d1007852
  • Description: This paper describes a conceptual framework for understanding the phases of casebased research. Case-based strategies in research are widely used in case study methodology as well as in a number of qualitative methodologies including grounded theory development, phenomenological research method and psychotherapy process research. The epistemological principles upon which casebased research is based are fundamentally different those which inform groupbased research using quantitative multivariate statistics. The case-based research process is divided into three general phases: descriptive, theoretical-heuristic, and theory-testing. Each of these phases is subdivided into two categories. The aims and epistemological principles related to each phase are discussed and illustrated with examples from contemporary research. The principles for establishing validity in case-base research are also reviewed and, in order to assist research students and supervisors, some common pitfalls are noted. The paper shows that rigorous work with single cases or series of cases using case-based principles and methodology is indeed, as Bromley (1986) claimed, "the bedrock of scientific investigation".
  • Full Text:
  • Date Issued: 1998

Umagungqel' indawo

Umzi kaMzwandile

  • Disclaimer
  • Privacy
  • Copyright
  • Contact