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Diet and daily ration of two nototheniid fish on the shelf of the sub-Antarctic Prince Edward Islands

  • Authors: Bushula, T , Pakhomov, E A , Kaehler, Sven , Davis, S , Kalin, R M
  • Date: 2005
  • Language: English
  • Type: Article
  • Identifier: vital:6948 , http://hdl.handle.net/10962/d1011977
  • Description: The seasonal dietary composition and estimates of daily consumption rate of Lepidonotothen larseni and Gobionotothen marionensis juveniles were obtained for the first time using fish collected near sub-Antarctic Prince Edward Islands during April 1999–2003. The diet of L. larseni consisted mainly of pelagic prey, with copepods and arrow worms making up the most significant prey groups and accounting for 46% and 40% of prey mass, respectively. The diet of G. marionensis was more diverse than that of L. larseni and was composed mainly of benthic prey, including bottom-dwelling decapods (Nauticaris marionis) and sedentary polychaetes, which accounted for 54% and 30% of prey mass, respectively. During the present study, dietary overlap between juveniles of L. larseni and G. marionensis was very low (<5%) indicating that competition for food resources between them was negligible. They not only relied on different prey species, both also exhibited different diel feeding regimes. Daily consumption rate of L. larseni and G. marionensis juveniles was estimated to be 4.5% and 5.2% of body dry mass, respectively. Stomach contents and stable isotope analyses suggested, that both L. larseni and G. marionensis occupy the forth-trophic level of the sub-Antarctic food web but depend mainly on allochthonous and autochthonous (kelp derived) organic matter, respectively.
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  • Date Issued: 2005

Dimensions of guest house service: perceptions of owners and expectations of business travellers

  • Authors: Wang, Yi
  • Date: 2005
  • Subjects: Hospitality industry -- Customer relations , Boardinghouses -- Customer services -- South Africa , Consumer satisfaction -- South Africa
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:9354 , http://hdl.handle.net/10948/d1006215 , Hospitality industry -- Customer relations , Boardinghouses -- Customer services -- South Africa , Consumer satisfaction -- South Africa
  • Description: The need for successful management of a guest house in the increasingly competitive hospitality industry in South Africa, compels guest house owners to understand their customers’ needs and deliver service of acceptable quality. The objective of the research is to find out what business travellers expect from a guest house and how these expectations compare with the perceptions of guest house owners in Port Elizabeth. Conclusions drawn from this research would also benefit guest house owners in other parts of the country. A literature review was conducted to provide an understanding of the nature of service and the role “evidence of service” can play in the perception of quality. The empirical study aimed at comparing business travellers’ expectations of guest house service with guest house owners’ perceptions of their guests’ expectations. The empirical findings showed that business travellers deemed secure parking and professionalism of staff as the most important attributes, while guest house owners thought it would be friendliness of front desk staff and efficient handling of complaints. Moreover, both groups indicated that cleanliness of rooms and services performed by staff adequately the first time, were of particular importance. It was also found that the importance rating of the different service dimensions were not significantly influenced by the business travellers’ gender, managerial position, nights of stay or by the guest house grading. The study proposes that guest house owners continue to focus on strategies for training and developing competent employees, simplify the steps of service delivery and improve on the standards of the servcie to ensure that business facilities are in line with the expectations of business travelers.
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  • Date Issued: 2005

Discourses surrounding 'race', equity, disadvantage and transformation in times of rapid social change : higher education in post-apartheid South Africa

  • Authors: Robus, Donovan
  • Date: 2005
  • Subjects: Rhodes University , University of Fort Hare , Universities and colleges -- Mergers -- South Africa , Education, Higher -- South Africa , Education and state -- South Africa , Apartheid -- South Africa , Discourse analysis -- Methodology , Discrimination in education -- South Africa , Educational change -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSocSc
  • Identifier: vital:3142 , http://hdl.handle.net/10962/d1007196 , Rhodes University , University of Fort Hare , Universities and colleges -- Mergers -- South Africa , Education, Higher -- South Africa , Education and state -- South Africa , Apartheid -- South Africa , Discourse analysis -- Methodology , Discrimination in education -- South Africa , Educational change -- South Africa
  • Description: Since the dismantling of Apartheid in South Africa in 1994, the South African socio-political and economic landscape has been characterised by rapid change. In the ten years since the 'new' democratic South Africa emerged, transformation has become a dominant discourse that has driven much action and practice in a variety of public areas. One of the areas of focus for transformation has been Higher Education whereby the Department of Education aimed to do away with disparity caused by Apartheid segregation by reducing the number of Higher Education institutions from 36 to 21. This research draws on Foucauldian theory and post-colonial theories (in particular Edward Said and Frantz Fanon), and the concept of racialisation in an analysis of the incorporation of Rhodes University's East London campus into the University of Fort Hare. Ian Parker's discourse analytic approach which suggests that discourses support institutions, reproduce power relations and have ideological effects, was utilised to analyse the talk of students and staff at the three sites affected by the incorporation (viz. Rhodes, Grahamstown, Rhodes, East London and Fort Hare) as well as newspaper articles and public statements made by the two institutions. What emerged was that in post-Apartheid South Africa, institutional and geographic space is still racialised with virtually no reference to the historical and contextual foundations from which this emerged being made. In positioning space and institutions in this racialised manner a discourse of 'white' excellence and 'black' failure emerges with the notion of competence gaining legitimacy through an appeal to academic standards. In addition to this, transformation emerges as a signifier of shifting boundaries in a post-Apartheid society where racialised institutional, spatial and social boundaries evidently still exist discursively.
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  • Date Issued: 2005

Draft Gender Indicators

  • Authors: COSATU
  • Date: 2005
  • Subjects: COSATU
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/172109 , vital:42160
  • Description: Women in both the trade union movement and the formal work environment face obstacles which inhibit the progress of their concerns. Despite a range of gender resolutions passed at trade union congresses and the equality clauses inherent in the constitution and labour legislation, issues of particular concern to women are not mainstreamed in trade union negotiations. In instances where issues such as maternity benefits are fully integrated, women workers may still face difficult choices when it comes to ensuring that rights and labour laws are adhered to in the workplace. Many women workers often find that their position at work has been changed while they have been off on maternity leave, or they have been included in a retrenchment negotiation while away. An important question to ask in building a framework of gender indicators for collective bargaining, are what are the obstacles in trade unions which inhibit women’s active participation in collective bargaining?
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  • Date Issued: 2005

Duress in the Roman-Dutch law of obligations

  • Authors: Glover, Graham B
  • Date: 2005
  • Language: English
  • Type: Article
  • Identifier: vital:6337 , http://hdl.handle.net/10962/d1012402
  • Description: [From the introduction]: The institutional writers and practitioners of 16th, 17th and 18th century Roman- Dutch law looked to the Roman law of obligations to form the foundation upon which they erected their structure of private law. During the course of the reception, the idea was that Roman law was supposed to be referred to and applied only where the indigenous law did not already cater for a legal problem.
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  • Date Issued: 2005

Effective management of an information technology professional's career

  • Authors: Tedder, Derek
  • Date: 2005
  • Subjects: Information technology -- Vocational guidance , Information technology -- Management , Knowledge management , Career development , Computer Science -- Vocational guidance , System analysis -- Vocational guidance
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: vital:1148 , http://hdl.handle.net/10962/d1004543 , Information technology -- Vocational guidance , Information technology -- Management , Knowledge management , Career development , Computer Science -- Vocational guidance , System analysis -- Vocational guidance
  • Description: The human resource is constantly cited as an organisation's greatest asset. In a rapidly changing technological environment this is most applicable to the Information Technology (IT) function. Organisations are experiencing IT human resource problems such as low satisfaction, early plateauing, high turnover, burnout, limited advancement potential, nominal corporate commitment, supervisory aversion, poor organisational culture, and exceptional compensation. These problems are directly related to the IT professional's career. There is a lack of information and awareness surrounding IT careers to deal effectively with these problems. The research aims to create increased awareness of IT careers and the inherent problems through the development of a career management model. The research aims to identify the factors that influence IT careers, provide career management with a means to measure compatibility of the factors, and suggest solutions to incompatibility. The solving of this problem will be of mutual benefit to both organisations and individuals as they seek to better manage IT careers. After reviewing research literature relating to career anchors, IT job types, IT skills portfolios, and career dynamics a model for Effective IT Career Management (EITCM) has been constructed. The model represents the dynamic interactions between individual, organisational, and dependent factors. The model examines the compatibility of these interacting factors by measuring the levels of relevant career variables. The model suggests appropriate career management techniques to increase the compatibility of the interacting factors. An empirical study was designed and launched online to provide data that would confirm the seven Critical Success Factors (CSF) relating to the proposed model. The responses from the members of the Computer Society of South Africa (CSSA) allowed the seven hypotheses derived from the CSFs to be tested. The results of the empirical study were positive but required modification to five of the CSFs before they could be confirmed. The EITCM model was modified to reflect the improved CSFs. An awareness of career influencing factors combined with active career management is advantageous to both IT professionals and their organisations.
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  • Date Issued: 2005

Effects of central metal on the photophysical and photochemical properties of non-transition metal sulfophthalocyanine

  • Authors: Ogunsipe, Abimbola , Nyokong, Tebello
  • Date: 2005
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/289337 , vital:56623 , xlink:href="https://doi.org/10.1142/S1088424605000186"
  • Description: The photophysical and photochemical properties and quenching (by 1,4-benzoquinone) of metallophthalocyanine sulfonates of aluminium (AlPcSmix), zinc (ZnPcSmix), silicon (SiPcSmix), germanium (GePcSmix) and tin (SnPcSmix) are presented. The quantum yield values of fluorescence (ΦF), triplet state (ΦT), singlet oxygen (ΦΔ) and photodegradation (Φd) were determined and the observed trends in their variation among the complexes discussed in terms of aggregation and the heavy atom effect. 1,4-benzoquinone effectively quenched the fluorescence of the complexes. Quenching analyses gave positive deviations from Stern-Volmer behavior, suggesting the existence of static quenching in addition to dynamic quenching. The static and dynamic components of the quenching were separated using a modified Stern-Volmer equation and the “sphere of action quenching model”. The quenching constant was found to be a function of the radius of the central metal ion.
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  • Date Issued: 2005

Electro-oxidation of phenol and its derivatives on poly-Ni (OH) TPhPyPc modified vitreous carbon electrodes

  • Authors: Obirai, Joseph , Bedioui, Fethi , Nyokong, Tebello
  • Date: 2005
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/289353 , vital:56625 , xlink:href="https://doi.org/10.1016/j.jelechem.2004.11.006"
  • Description: The electrochemical oxidation of phenol and its derivatives using poly-nickel hydroxy tetraphenoxypyrrolephthalocyanine (poly-Ni(OH)TPhPyPc) modified vitreous carbon electrodes are described. The films were formed by the electro-transformation of the electropolymerized pyrrole-substituted phenoxyphthalocyanine poly-NiTPhPyPc modified electrode in aqueous 0.1 M NaOH solution. The poly-Ni(OH)TPhPyPc films showed better stability and resistance to electrode fouling compared to poly-NiTPhPyPc and unmodified electrodes. The resistance to surface fouling and stability can be attributed to the structure of the ring substituent on the phthalocyanine macrocycle and to the particular O–Ni–O bridged architecture of the nickel phthalocyanine film.
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  • Date Issued: 2005

Electrocatalytic oxidation and detection of hydrazine at gold electrode modified with iron phthalocyanine complex linked to mercaptopyridine self-assembled monolayer

  • Authors: Ozoemena, Kenneth I , Nyokong, Tebello
  • Date: 2005
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/286065 , vital:56235 , xlink:href="https://doi.org/10.1016/j.talanta.2005.02.030"
  • Description: Electrocatalytic oxidation and detection of hydrazine in pH 7.0 conditions were studied by using gold electrode modified with self-assembled monolayer (SAM) films of iron phthalocyanine (FePc) complex axially ligated to a preformed 4-mercaptopyridine SAMs. The anodic oxidation of hydrazine in neutral pH conditions with FePc-linked-mercaptopyridine-SAM-modified gold electrode occurred at low overpotential (0.35 V versus Ag|AgCl) and the treatment of the voltammetric data showed that it was a pure diffusion-controlled reaction with the involvement of one electron in the rate-determining step. The mechanism for the interaction of hydrazine with the FePc-SAM is proposed to involve the Fe(III)Pc/Fe(II)Pc redox process. Using cyclic voltammetry (CV) and Osteryoung square wave voltammetry (OSWV), hydrazine was detected over a linear concentration range of 1.3 × 10−5 to 9.2 × 10−5 mol/L with low limits of detection (ca. 5 and 11 μM for OSWV and CV, respectively). At concentrations higher than 1.2 × 10−4 mol/L the anodic peak potential shifted to 0.40 V (versus Ag|AgCl), and this was interpreted to be due to kinetic limitations resulting from the saturation of hydrazine and its oxidation products onto the redox-active monolayer film. This type of metallophthalocyanine-SAM-based electrode is a highly promising electrochemical sensor given its ease of fabrication, good catalytic activity, stability, sensitivity and simplicity.
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  • Date Issued: 2005

Electropolymerized Pyrrole-Substituted Manganese Phthalocyanine Films for the Electroassisted Biomimetic Catalytic Reduction of Molecular Oxygen

  • Authors: Rodrigues, Nazaré Pereira , Obirai, Joe , Nyokong, Tebello , Bedioui, Fethi
  • Date: 2005
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/289372 , vital:56626 , xlink:href="https://doi.org/10.1002/elan.200403064"
  • Description: We report for the first time on the electroassisted biomimetic activation of molecular oxygen by a newly prepared electropolymerized polypyrrole-manganese phthalocyanine film. The prepared films and their intervention in the electroassisted catalytic reduction of molecular oxygen were analyzed by cyclic voltammetry and UV-visible spectrophotometry on optically transparent electrodes. The obtained results demonstrate the probable existence of the key-steps responsible for the suggested formation of the highly reactive manganese oxo intermediate.
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  • Date Issued: 2005

Enabling reflexivity and the development of reflexive competence within course processes: a case study of an environmental education professional development course

  • Authors: Raven, Glenda C
  • Date: 2005
  • Subjects: Rhodes University / Gold Fields Course in Environmental Education Environmental education -- Research -- South Africa Environmental education -- South Africa -- Curricula Competency-based education -- South Africa Education and state -- South Africa Education -- Research
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:1507 , http://hdl.handle.net/10962/d1003389
  • Description: This research was undertaken in the context of socio-economic transformation in South Africa, and more specifically, in the context of change in education policy. To support socio-economic transformation in South Africa after the first democratic elections in 1994, a competence-based National Qualifications Framework (NQF) was introduced in 1995. In responding to the particular socio-historical context of South Africa, the South African NQF is underpinned by the notion of applied competence, integrating practical, foundational and reflexive competence, which is the key and distinguishing feature of this competence-based framework. In this context of transformation, the research was aimed at an in-depth exploration of the notion of reflexivity and reflexive competence, and course processes that enable its development, with a view to providing curriculum development insights for learning programme development in the competence-based NQF, more broadly, and environmental education professional development programmes, more specifically. To enable these aims, the research was undertaken in the context of the Rhodes University / Gold Fields Participatory Course in Environmental Education (RU/GF course), as a case example of a professional development course that aims to develop critically reflexive practitioners. Within an interpretivist orientation, a multiple-embedded case study approach was used to gain insight into the relationship between course processes, reflexivity and the development of reflexive competence to clarify and provide a critical perspective on how competence develops in the context of the course. Data was collected over a period of one year using observation, interviewing and document analysis as the primary data collection techniques. Data was analysed through various phases and layers to inform data generation and the synthesising of data for further interpretation. Through the literature review undertaken within the study, various significant insights emerged around the notion of reflexivity and reflexive competence. Firstly, there appears to be a need to distinguish between reflexivity as social processes of change (social actions and interactions within social systems, structures and processes) and reflexive competence (a range of integrative elements of competence) that provides the evidence of an engagement within social processes of change. The second key insight emerging is the significance of social structure in shaping participation in reflexive processes, thus emphasising the duality of structure as both the medium for, and outcome of reflexive social actions and interactions and so challenges the deterministic conception of social structure. Further, the significance of an epistemologically framed notion of reflexivity and reflexive competence emerged, in the context of responding to the complex and uncertain quality of socio-ecological risks and in supporting change in context. Reflexivity, distinguished from processes of critical reflection, foregrounds a critical exploration of both knowledge and unawareness. As such a reinterpretation of reflexive competence is offered as a process of potential challenge to dominant and reigning forms of reasoning (knowledge frameworks) and consequent principles of ordering. Through this reframing of reflexive competence, the potential exists to destabilise dominant forms of reasoning and principles of ordering to create a broader scope of possibilities for action and change in context. This reframing of reflexive competence in the context of transformation in South Africa has critical implications for engaging within processes of learning programme design in the NQF to support an engagement within reflexive processes of change and the development of a range of integrative elements of reflexive competence. In this light, the study attempts to make the following contribution to curriculum deliberations within the context of environmental education and the NQF in relation to reflexivity, reflexive competence and change: ♦ Reflexivity is conceptualised as social processes of change with reflexive competence providing evidence of engagement within these social processes of change; ♦ An epistemologically framed conception of reflexivity and reflexive competence recognises how rules of reason and the ordering of the ‘reasonable’ person come to shape social life; and so ♦ Change is conceptualised as ruptures and breaks in dominant knowledge frames and the power relations embedded in these; ♦ Unawareness emerges as a key dimension within reflexive environmental education processes in responding to the unpredictable and uncertain nature of risks; ♦ An epistemological framing of reflexivity and reflexive competence highlights the need to develop open processes of learning to support the critical exploration of knowledge and unawareness; and ♦ Within this framing of reflexivity and reflexive competence, the difficulty emerges in specifically predefining reflexive competence to inform standard setting processes within a context of intended change. In framing data within this emerging conception of reflexivity and reflexive competence, a review of course processes highlighted potential areas for reorienting the RU/GF course to support change in context, for which I make specific recommendations. Drawing on the review of course processes in the RU/GF course, and in light of the reframing of reflexivity and reflexive competence, I further offer summative discussions as ‘possible implications’ for learning programme design in the South African competence-based NQF, broadly and environmental education professional development programmes in this framework, more specifically.
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  • Date Issued: 2005

Enzymatic recovery of rhodium(III) from aqueous solution and industrial effluent using sulphate reducing bacteria: role of a hydrogenase enzyme

  • Authors: Ngwenya, Nonhlanhla
  • Date: 2005
  • Subjects: Enzymes , Rhodium , Enzymes -- Industrial applications , Sulfur bacteria , Hydrogenation , Hydragenase , Factory and trade waste -- Purification
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:3956 , http://hdl.handle.net/10962/d1004015 , Enzymes , Rhodium , Enzymes -- Industrial applications , Sulfur bacteria , Hydrogenation , Hydragenase , Factory and trade waste -- Purification
  • Description: In an attempt to overcome the high maintenance and costs associated with traditional physico-chemical methods, much work is being done on the application of enzymes for the recovery of valuable metals from solutions and industrial effluents. One of the most widely studied enzymatic metal recovery systems uses hydrogenase enzymes, particularly from sulphate reducing bacteria (SRB). While it is known that hydrogenases from SRB mediate the reductive precipitation of metals, the mechanism of enzymatic reduction, however, is not yet fully understood. The main aim of the present study was to investigate the role of a hydrogenase enzyme in the removal of rhodium from both aqueous solution and industrial effluent. A quantitative analysis of the rate of removal of rhodium(III) by a resting SRB consortium under different initial rhodium and biomass concentrations, pH, temperature, presence and absence of SRB cells and electron donor, was studied. Rhodium speciation was found to be the main factor controlling the rate of removal of rhodium from solution. SRB cells were found to have a higher affinity for anionic rhodium species, as compared to both cationic and neutral species, which become abundant when speciation equilibrium was reached. Consequently, a pH-dependant rate of rhodium removal from solution was observed. The maximum SRB uptake capacity for rhodium was found to be 66 mg rhodium per g of resting SRB biomass. Electron microscopy studies revealed a time-dependant localization and distribution of rhodium precipitates, initially intracellularly and then extracellularly, suggesting the involvement of an enzymatic reductive precipitation process. A hydrogenase enzyme capable of reducing rhodium(III) from solution was isolated and purified by PEG, DEAE-Sephacel anion exchanger and Sephadex G200 gel exclusion. A distinct protein band with a molecular weight of 62kDa was obtained when the hydrogenase containing fractions were subjected to a 10% SDS-PAGE. Characterization studies indicated that the purified hydrogenase had an optimum pH and temperature of 8 and 40°C, respectively. A maximum of 88% of the initial rhodium in solution was removed when the purified hydrogenase was incubated under hydrogen. Due to the low pH of the industrial effluent (1.31), the enzymatic reduction of rhodium by the purified hydrogenase was greatly retarded. It was apparent that industrial effluent pretreatment was necessary before the application an enzymatic treatment method. In the present study, however, it has been established that SRB are good candidates for the enzymatic recovery of rhodium from both solution and effluent.
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  • Date Issued: 2005

Establish to what extent small and medium enterprises (SMEs) in the Port Elizabeth CBD comply with good governance principles and practices

  • Authors: Mpafa, Dumisani
  • Date: 2005
  • Subjects: Corporate governance , Small business -- South Africa -- Port Elizabeth
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: vital:10904 , http://hdl.handle.net/10948/163 , Corporate governance , Small business -- South Africa -- Port Elizabeth
  • Description: Throughout the world, corporate or good governance has become such a dominating terminology in the ever -increasing business vocabulary. Its fast rise and strategic relevance to the global business communi ty is part ly due to the desi re by the business leaders wor ldwide to be seen to be doing something about the scourge of corporate failures resulting f rom poor governance. The objective of the research was to establish to what extent Smal l and Medium Enterpr ises (SMEs) comply with good governance principles and practices. The SMEs in the Port Elizabeth CBD were chosen as the representative population of the SME sector throughout the country. The research methodology included: A li terature study to determine, on the one hand the current good governance pract ices global ly, and on the other the role, relevance and the challenges of the SMEs in the South Af rican Economy. An empir ical study in order to obtain the empir ical evidence concerning SME compliance to good governance principles and pract ice. This was done through a survey of SME sector in the Port Elizabeth CBD. Lastly, the conclusion and recommendations. The conclusion was reached, inter alia, that the major ity of SMEs do not comply wi th good governance principles and pract ices for various reasons. Therefore the following recommendations were made: Recommended that the organisational accountants appointed in terms of the law should not confine themselves to the financial aspects of the business only, but also look at governance of these small businesses. Recommended that a sub-code for SMEs be developed. Recommended that the existing code of governance be amended to include a clause that requires large and establish businesses to insist on good governance in the SMEs they deal with at any level. Recommended that the South African Qualifications Authority (SAQA) should develop a qualification or unit standard on good governance to facilitate training on good governance. Since good governance knowledge is a key competence for every manager, especially senior management. It is recommended that institutions of higher learning should have good governance in their curriculum.
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  • Date Issued: 2005

Establishing an information security culture in organizations : an outcomes based education approach

  • Authors: Van Niekerk, Johannes Frederick
  • Date: 2005
  • Subjects: Computer security , Management information systems -- Security measures , Competency-based education
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:9742 , http://hdl.handle.net/10948/164 , Computer security , Management information systems -- Security measures , Competency-based education
  • Description: Information security is crucial to the continuous well-being of modern orga- nizations. Humans play a signfiicant role in the processes needed to secure an organization's information resources. Without an adequate level of user co-operation and knowledge, many security techniques are liable to be misused or misinterpreted by users. This may result in an adequate security measure becoming inadequate. It is therefor necessary to educate the orga- nization's employees regarding information security and also to establish a corporate sub-culture of information security in the organization, which will ensure that the employees have the correct attitude towards their security responsibilities. Current information security education programs fails to pay su±cient attention to the behavioral sciences. There also exist a lack of knowledge regarding the principles, and processes, that would be needed for the establishment of an corporate sub-culture, specific to information security. Without both the necessary knowledge, and the desired attitude amongst the employee, it will be impossible to guarantee that the organi- zation's information resources are secure. It would therefor make sense to address both these dimensions to the human factor in information security, using a single integrated, holistic approach. This dissertation presents such an approach, which is based on an integration of sound behavioral theories.
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  • Date Issued: 2005

Establishment and impact of the sap-sucking mirid, Falconia intermedia (Distant) (Hemiptera: Miridae) on Lantana camara (Verbenaceae) varieties in the Eastern Cape Province, South Africa

  • Authors: Heshula, Unathi-Nkosi Lelethu Peter
  • Date: 2005
  • Subjects: Lantana camara -- South Africa -- Eastern Cape , Biological pest control agents -- South Africa -- Eastern Cape , Hemiptera -- South Africa -- Eastern Cape , Miridae -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5832 , http://hdl.handle.net/10962/d1008085
  • Description: The biological control of the weedy complex Lantana camara (L.) (Verbenaceae) has been ongoing in South Africa for over 40 years. Despite this, the weed is still not under sufficient control and continues to invade new territories in the country. The biological control programme needs to be bolstered with releases of new and potentially damaging biological control agents. A promising biological control agent endemic to Central America, Falconia intermedia (Distant) (Hemiptera: Miridae), was imported into quarantine from Jamaica in 1994. This agent was released on sites in KwaZulu-Natal and Limpopo provinces of South Africa in 1999. Even though it initially established and damaged L. camara, populations died out at most of the release sites. As varietal difference and adverse climate have been cited as the reason for non-establishment and ineffective control in L. camara biocontrol programmes worldwide, this study attempts to investigate the role that these two factors play in this weed herbivore relationship. Laboratory no-choice trials were conducted to determine the varietal performance of F intermedia, among five Eastern Cape varieties of the weed from East London, Whitney Farm, Heather Glen Farm, Port Alfred and Lyndhurst Farm, and a variety from the Plant Protection Research Institute (PPRI), Pretoria. However, there were differences in performance as the adult mirids performed better on white-pink varieties from Whitney Farm and Heather Glen Farm. To test varietal preference in field conditions, field releases of F intermedia were also made at East London, Whitney Farm, Heather Glen Farm, Port Alfred and Lyndhurst Farm. Post release evaluations were conducted monthly for two years (2002 and 2003). The insect established at East London and Whitney Farm, both of which have white-pink varieties. Insect populations quickly died out at the Lyndhurst Farm and Port Alfred sites, which have dark pink varieties. It is suggested that field conditions may have resulted in poor plant quality and led indirectly to varietal preference, and to non-establishment at these two sites. With the onset of cooler weather, populations disappeared at Heather Glen Farm. This suggested that F. intermedia was suitable for release in more subtropical areas within South Africa where climatic conditions would be suitable throughout the year. The mirid performed well at Whitney Farm, resulting in significant reduction in plant growth parameters such as height and percentage cover, and increasing the cover of other flora growing beneath L. camara plants. Finally, ways to improve the efficacy of this agent are considered in an effort towards better control of L. camara in South Africa.
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  • Date Issued: 2005

Estimating the potential role of commercial over-harvesting in resource viability: A case study of five useful tree species in South Africa

  • Authors: Shackleton, Charlie M , Guthrie, G , Main, R
  • Date: 2005
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/181324 , vital:43719 , xlink:href="https://doi.org/10.1002/ldr.652"
  • Description: There is a growing commercialization of non-timber forest products (NTFPs) as a means of livelihood by rural communities throughout the developing world. This often occurs in the absence of any clear understanding of or guidelines regarding sustainable yields and ecological impacts, which may undermine the success of NTFP enterprises, especially from arid regions. This paper reports on the use of size class profiles and three quantitative indices to examine population profiles of five potentially useful tree species used as NTFPs in the semiarid lowveld of South Africa. We also contrast the population densities of the five tree species in 2003 with data from 1992. Low stem densities and population profiles indicated that three of the five species would preclude the establishment of NTFP enterprises based on their products. The other two species seem to have sufficient densities for some harvesting to take place, within an adaptive management framework. However, the longitudinal data indicated that the density of both these species had significantly declined over an eleven-year period, highlighting the need for appropriate management institutions. Additionally, the proportion of mature stems cut, and the degree of cutting per stem, had increased for all five species over the eleven years. The three quantitative indices of population stability were not correlated with one another, and hence provided a useful suite of measures sensitive to different aspects of size class profiles and their interpretation.
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  • Date Issued: 2005

Euphausiid population structure and grazing in the Indian sector of the Antarctic Polar Frontal Zone, during austral autumn

  • Authors: Bernard, Anthony Thomas Firth
  • Date: 2005
  • Subjects: Euphausiacea -- Antarctic Ocean , Euphausiacea -- Feeding and feeds
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5913 , http://hdl.handle.net/10962/d1015960
  • Description: The trophodynamics of the numerically dominant euphausiid species within a region of high mesoscale oceanographic variability in the southwest Indian sector of the Antarctic Polar Frontal Zone (PFZ) were investigated during the austral autumns April/May) of 2004 and 2005. During the 2004 survey, sub-surface (200 m) temperature profiles indicated that an intense frontal feature, formed by the convergence of the Sub-Antarctic Front (SAF) and the Antarctic Polar Front (APF) bisected the survey area into two distinct zones, the Sub- Antarctic Zone (SAZ) and the Antarctic Zone (AAZ). Total integrated chlorophyll-a (chl-a) biomass was typical for the region (< 25 mg chl-a m⁻²), and was dominated by picophytoplankton. Total euphausiid abundance and biomass ranged from 0.1 to 3.1 ind m⁻³ and 0.1 to 8.1 mg dwt m⁻³, respectively, and did not differ significantly between the stations occupied in the SAZ and AAZ (p > 0.05). The multivariate analysis identified two interacting mechanisms controlling the distribution patterns, abundance and biomass of the various euphausiid species, namely (1) diel changes in abundance and biomass, (2) and restricted distribution patterns associated with the different water masses. Ingestion rates were determined for five euphausiid species. E. triacantha was found to have the highest daily ingestion rate ranging from 1 226.1 to 6 029.1 ng pigm ind⁻¹d⁻¹, while the lowest daily ingestion rates were observed in the juvenile Thysanoessa species (6.4 to 943.0 ng pigm ind⁻¹ d⁻¹). The total grazing impact of the selected euphausiids ranged from < 0.1 to 20.1 μg pigm m⁻²d⁻¹, corresponding to < 0.15 % of the areal chl-a biomass. The daily ration estimates of autotrophic carbon for the euphausiids suggested that phytoplankton represented a minor component in their diets, with only the sub-adult E. vallentini consuming sufficient phytoplankton to meet their daily carbon requirements. A cyclonic cold-core eddy spawned from the region of the APF located in the southwest Indian sector of the PFZ was the dominant feature during the 2005 survey. The total areal chl-a biomass throughout the region was low, ranging between 5.6 and 11.4 mg chl-a m⁻², and was significantly higher within the core of the eddy compared to the surrounding waters (p < 0.05). RMT-8 and WP-2 total euphausiid abundance and biomass estimates were high, and ranged from 0.004 to 0.36 ind m⁻³ and 0.065 to 1.21 mg dwt m⁻³, and from 0.01 to 18.2 ind m⁻³ and 0.01 to 15.7 mg dwt m⁻³, respectively. A distinct spatial pattern in the euphausiid community was evident with the Antarctic species, Euphausia frigida, E. triacantha and E. superba predominating within the core of the eddy, while the PFZ waters were characterized by the sub-Antarctic species, E. longirostris, Stylocheiron maximum, Nematoscelis megalops and Thysanoessa gregaria. The eddy edge acted as a transition zone where species from both regions co-occurred. Within the survey area the combined ingestion rate of the six numerically dominant euphausiid species ranged between 0.02 and 5.31 μg pigm m⁻²d¹, which corresponded to a loss of between < 0.001 and 0.11 % of the available chl-a biomass. E. triacantha and juvenile T. macura were identified as the dominant grazers. There was no apparent spatial pattern in the grazing activity of the euphausiids within the region of investigation. The average daily rations of the euphausiids examined were < 2 % of their body carbon. The low daily ration of the euphausiids could be ascribed to the predominance of small picophytoplankton in the region of investigation, which are too small to be grazed efficiently by larger zooplankton. The marked spatial patterns in species composition and the elevated abundance and biomass of euphausiids, suggest that the mesoscale eddies contribute to the spatial and temporal heterogeneity of the planktonic community of the PFZ and may represent important foraging regions for many of the apex predators within the region.
  • Full Text:
  • Date Issued: 2005

Evaluating parts-of-speech taggers for use in a text-to-scene conversion system

  • Authors: Glass, Kevin R , Bangay, Shaun D
  • Date: 2005
  • Language: English
  • Type: Conference paper
  • Identifier: vital:6603 , http://hdl.handle.net/10962/d1009323
  • Description: This paper presents parts-of-speech tagging as a first step towards an autonomous text-to-scene conversion system. It categorizes some freely available taggers, according to the techniques used by each in order to automatically identify word-classes. In addition, the performance of each identified tagger is verified experimentally. The SUSANNE corpus is used for testing and reveals the complexity of working with different tagsets, resulting in substantially lower accuracies in our tests than in those reported by the developers of each tagger. The taggers are then grouped to form a voting system to attempt to raise accuracies, but in no cases do the combined results improve upon the individual accuracies. Additionally a new metric, agreement, is tentatively proposed as an indication of confidence in the output of a group of taggers where such output cannot be validated.
  • Full Text:
  • Date Issued: 2005

Evaluating parts-of-speech taggers for use in a text-to-scene conversion system

  • Authors: Glass, Kevin R , Bangay, Shaun D
  • Date: 2005
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/432654 , vital:72890 , https://www.cs.ru.ac.za/research/groups/vrsig/currentprojects/053texttoscene/paper01.pdf
  • Description: This paper presents parts-of-speech tagging as a first step towards an autonomous text-to-scene conversion system. It categorizes some freely available taggers, according to the techniques used by each in order to automatically identify word-classes. In addition, the performance of each identified tagger is verified experimentally. The SUSANNE corpus is used for testing and reveals the complexity of working with different tagsets, resulting in substantially lower accuracies in our tests than in those reported by the developers of each tagger. The taggers are then grouped to form a voting system to attempt to raise accuracies, but in no cases do the combined results improve upon the individual accuracies. Additionally a new metric, agreement, is tentatively proposed as an indication of confidence in the output of a group of taggers where such output cannot be validated.
  • Full Text:
  • Date Issued: 2005

Exploring learners' mathematical understanding through an analysis of their solution strategies

  • Authors: Penlington, Thomas Helm
  • Date: 2005
  • Subjects: Mathematics -- Study and teaching (Elementary) Mathematics -- Problems, exercises, etc. Problem solving -- Study and teaching Reasoning Mathematical ability
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1934 , http://hdl.handle.net/10962/d1007642
  • Description: The purpose of this study is to investigate various solution strategies employed by Grade 7 learners and their teachers when solving a given set of mathematical tasks. This study is oriented in an interpretive paradigm and is characterised by qualitative methods. The research, set in nine schools in the Eastern Cape, was carried out with nine learners and their mathematics teachers and was designed around two phases. The research tools consisted of a set of 12 tasks that were modelled after the Third International Mathematics and Science Study (TIMSS), and a process of clinical interviews that interrogated the solution strategies that were used in solving the 12 tasks. Aspects of grounded theory were used in the analysis of the data. The study reveals that in most tasks, learners relied heavily on procedural understanding at the expense of conceptual understanding. It also emphasises that the solution strategies adopted by learners, particularly whole number operations, were consistent with those strategies used by their teachers. Both learners and teachers favoured using the traditional, standard algorithm strategies and appeared to have learned these algorithms in isolation from concepts, failing to relate them to understanding. Another important finding was that there was evidence to suggest that some learners and teachers did employ their own constructed solution strategies. They were able to make sense of the problems and to 'mathematize' effectively and reason mathematically. An interesting outcome of the study shows that participants were more proficient in solving word problems than mathematical computations. This is in contrast to existing research on word problems, where it is shown that teachers find them difficult to teach and learners find them difficult to understand. The findings of this study also highlight issues for mathematics teachers to consider when dealing with computations and word problems involving number sense and other problem solving type problems.
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  • Date Issued: 2005
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