Synthesis, spectroscopy and electrochemistry of octaphenoxyphthalocyaninato silicon complexes
- Maree, M David, Nyokong, Tebello
- Authors: Maree, M David , Nyokong, Tebello
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304863 , vital:58497 , xlink:href="https://doi.org/10.1002/jpp.361"
- Description: A number of octaphenoxyphthalocyaninato silicon complexes containing a variety of axial ligands, represented by (OPh)8PcSi(X)2 (where X = chloro 3, hydroxy 4, (4-carboxybenzene) acetato 5, isonicatinato 6, propionato 7, nitrophenoxy 8 and dimethylaminoxy 9) have been synthesized using a convenient route starting with the 4,5-diphenoxy-1,2-dicyanobenzene. 1H NMR and UV/vis spectra, and the cyclic voltammetry of the complexes are reported. The complexes are obtained in high yield and are soluble in many organic solvents. Cyclic voltammetry revealed two reduction couples and one oxidation couple for these complexes. Analysis of the cyclic voltammograms showed that compounds 6 and 8 were easier to oxidize and more difficult to reduce than the rest. Also cyclic voltammetry data suggested that electron transfer was not governed only by diffusion.
- Full Text:
- Date Issued: 2001
- Authors: Maree, M David , Nyokong, Tebello
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304863 , vital:58497 , xlink:href="https://doi.org/10.1002/jpp.361"
- Description: A number of octaphenoxyphthalocyaninato silicon complexes containing a variety of axial ligands, represented by (OPh)8PcSi(X)2 (where X = chloro 3, hydroxy 4, (4-carboxybenzene) acetato 5, isonicatinato 6, propionato 7, nitrophenoxy 8 and dimethylaminoxy 9) have been synthesized using a convenient route starting with the 4,5-diphenoxy-1,2-dicyanobenzene. 1H NMR and UV/vis spectra, and the cyclic voltammetry of the complexes are reported. The complexes are obtained in high yield and are soluble in many organic solvents. Cyclic voltammetry revealed two reduction couples and one oxidation couple for these complexes. Analysis of the cyclic voltammograms showed that compounds 6 and 8 were easier to oxidize and more difficult to reduce than the rest. Also cyclic voltammetry data suggested that electron transfer was not governed only by diffusion.
- Full Text:
- Date Issued: 2001
Talking about teams within a team building context: a discourse analytic study
- Authors: Chapman-Blair, Sharon
- Date: 2001
- Subjects: Discourse analysis , Teams in the workplace
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2947 , http://hdl.handle.net/10962/d1002456 , Discourse analysis , Teams in the workplace
- Description: This research initiative responds to some of the issues raised by theoretical challenges leveled at Industrial Psychology (postmodernism), and practical challenges in the workplace (the use of teams) by investigating notions of what a team is via the postmodern methodology of discourse analysis. The research explores “team talk” – repertoires of speech employed by individuals to construct particular versions of “the team” for specific effects, of importance given emphasis placed on shared understanding, expectations and goals in a “team”. A Rhodes University Industrial Psychology Honours class required to work as a team (having participated in a team building exercise), as well as their lecturers who facilitated the team building process were interviewed to obtain “talk” to analyse. This uncovered a multiplicity of meaning, namely four ways of speaking about (constructing) the team. These repertoires are explored in terms of how they are constructed, how they differ across context and speakers, how they interrelate and what they function to achieve. The educational team repertoire constructs academic hierarchy, justifies individualism, positions members as experts and maintains distance from interpersonal processes. The machine repertoire divides work and interpersonal issues, regulates productivity and constructs team roles (defining individual activity and “team fit”), but is inflexible to change. The family repertoire voices emotive aspects to maintain cohesion via conformity, leaderlessness, group identity and shared achievement, but cannot accommodate conflict or workpersonal boundaries. The psychologised team repertoire constructs the team primarily as a therapeutic entity legitimately creating individual identities (and expertise) and facilitating personal growth, but this flounders when support in the “team” fails. Given that each repertoire has a different emphasis (reflective learning versus work processes versus building relationships versus personal growth), there are slippages / clashes between repertoires. This postmodern look at “the team” thus assists in recognizing and problematising these multiple meanings and identifying practical implications.
- Full Text:
- Date Issued: 2001
- Authors: Chapman-Blair, Sharon
- Date: 2001
- Subjects: Discourse analysis , Teams in the workplace
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2947 , http://hdl.handle.net/10962/d1002456 , Discourse analysis , Teams in the workplace
- Description: This research initiative responds to some of the issues raised by theoretical challenges leveled at Industrial Psychology (postmodernism), and practical challenges in the workplace (the use of teams) by investigating notions of what a team is via the postmodern methodology of discourse analysis. The research explores “team talk” – repertoires of speech employed by individuals to construct particular versions of “the team” for specific effects, of importance given emphasis placed on shared understanding, expectations and goals in a “team”. A Rhodes University Industrial Psychology Honours class required to work as a team (having participated in a team building exercise), as well as their lecturers who facilitated the team building process were interviewed to obtain “talk” to analyse. This uncovered a multiplicity of meaning, namely four ways of speaking about (constructing) the team. These repertoires are explored in terms of how they are constructed, how they differ across context and speakers, how they interrelate and what they function to achieve. The educational team repertoire constructs academic hierarchy, justifies individualism, positions members as experts and maintains distance from interpersonal processes. The machine repertoire divides work and interpersonal issues, regulates productivity and constructs team roles (defining individual activity and “team fit”), but is inflexible to change. The family repertoire voices emotive aspects to maintain cohesion via conformity, leaderlessness, group identity and shared achievement, but cannot accommodate conflict or workpersonal boundaries. The psychologised team repertoire constructs the team primarily as a therapeutic entity legitimately creating individual identities (and expertise) and facilitating personal growth, but this flounders when support in the “team” fails. Given that each repertoire has a different emphasis (reflective learning versus work processes versus building relationships versus personal growth), there are slippages / clashes between repertoires. This postmodern look at “the team” thus assists in recognizing and problematising these multiple meanings and identifying practical implications.
- Full Text:
- Date Issued: 2001
Teenage motherhood and the regulation of mothering in the scientific literature: the South African example
- Authors: Macleod, Catriona I
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6256 , http://hdl.handle.net/10962/d1007874
- Description: The mainstream literature on teenage pregnancy highlights teenagers' inadequate mothering as an area of disquiet. `Revisionists', such as feminist critics, point out that a confluence of negative social factors is implicated in teenagers' mothering abilities. Whether arguing that teenagers make bad mothers or defending them against this, the literature relies on the `invention of "good" mothering'. In this article I highlight the taken-for-granted assumptions concerning mothering (mothering as an essentialized dyad; mothering as a skill; motherhood as a pathway to adulthood; fathering as the absent trace) appearing in the scientific literature on teenage pregnancy in South Africa. I indicate how these assumptions are implicated in the regulation of mothering through the positioning of the teenage mother as the pathologized other, the splitting of the public from the private, domestic space of mothering, and the legitimation of the professionalization of mothering. I explore the gendered implications of the representations of mothering in this literature.
- Full Text:
- Date Issued: 2001
- Authors: Macleod, Catriona I
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6256 , http://hdl.handle.net/10962/d1007874
- Description: The mainstream literature on teenage pregnancy highlights teenagers' inadequate mothering as an area of disquiet. `Revisionists', such as feminist critics, point out that a confluence of negative social factors is implicated in teenagers' mothering abilities. Whether arguing that teenagers make bad mothers or defending them against this, the literature relies on the `invention of "good" mothering'. In this article I highlight the taken-for-granted assumptions concerning mothering (mothering as an essentialized dyad; mothering as a skill; motherhood as a pathway to adulthood; fathering as the absent trace) appearing in the scientific literature on teenage pregnancy in South Africa. I indicate how these assumptions are implicated in the regulation of mothering through the positioning of the teenage mother as the pathologized other, the splitting of the public from the private, domestic space of mothering, and the legitimation of the professionalization of mothering. I explore the gendered implications of the representations of mothering in this literature.
- Full Text:
- Date Issued: 2001
Ten years in defence and advancement of worker rights
- SACTWU
- Authors: SACTWU
- Date: 2001
- Subjects: SACTWU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/111063 , vital:33369
- Description: Whereas the SOUTHERN AFRICAN CLOTHING AND TEXTILE WORKERS' UNION is an association not for gain, non-racial registered trade union, unaffiliated to any political party and whereas the SOUTHERN AFRICAN CLOTHING AND TEXTILE WORKERS' UNION is dedicated and committed - irrespective of race, colour, creed or sex: to promote and maintain free democratic trade unionism for all workers in Southern Africa and to oppose the exploitation of cheap labour; to advance the dignity, rights, socio-economic and cultural well-being of all workers in Southern Africa through collective bargaining and free negotiation; to do all in our power to assist in fully developing the full potential of workers and their children in the economic, social, political and cultural fields; to oppose any forms of discrimination which could prevent all the people of this land from being able to trade, manufacture, practise all crafts, trades and professions and own land, live and be educated where and as they choose; to defend the right to equal status in the eyes of the law for all people and to support the rule of just law; to maintain the right to free compulsory and equal education for all children and the opportunity for all students to receive the highest specialised training; to promote the right to full employment for all people of Southern Africa; to promote the right for all people to live where they choose, to be properly and decently housed, and to raise their families in security and comfort; to promote a system whereby the aged and infirm are supported regardless of income or status; to pursuing an enlightened programme to assist unorganised workers, and to develop educational facilities within the trade union movement; to disseminate as widely as possible press democratic trade union principles among all workers in the industry; to promote the sharing of the fruits of the labour of all workers in the industry.
- Full Text:
- Date Issued: 2001
- Authors: SACTWU
- Date: 2001
- Subjects: SACTWU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/111063 , vital:33369
- Description: Whereas the SOUTHERN AFRICAN CLOTHING AND TEXTILE WORKERS' UNION is an association not for gain, non-racial registered trade union, unaffiliated to any political party and whereas the SOUTHERN AFRICAN CLOTHING AND TEXTILE WORKERS' UNION is dedicated and committed - irrespective of race, colour, creed or sex: to promote and maintain free democratic trade unionism for all workers in Southern Africa and to oppose the exploitation of cheap labour; to advance the dignity, rights, socio-economic and cultural well-being of all workers in Southern Africa through collective bargaining and free negotiation; to do all in our power to assist in fully developing the full potential of workers and their children in the economic, social, political and cultural fields; to oppose any forms of discrimination which could prevent all the people of this land from being able to trade, manufacture, practise all crafts, trades and professions and own land, live and be educated where and as they choose; to defend the right to equal status in the eyes of the law for all people and to support the rule of just law; to maintain the right to free compulsory and equal education for all children and the opportunity for all students to receive the highest specialised training; to promote the right to full employment for all people of Southern Africa; to promote the right for all people to live where they choose, to be properly and decently housed, and to raise their families in security and comfort; to promote a system whereby the aged and infirm are supported regardless of income or status; to pursuing an enlightened programme to assist unorganised workers, and to develop educational facilities within the trade union movement; to disseminate as widely as possible press democratic trade union principles among all workers in the industry; to promote the sharing of the fruits of the labour of all workers in the industry.
- Full Text:
- Date Issued: 2001
The assessment of first-line management competencies at a selected automotive manufacturer using a recognition of prior learning approach
- Authors: Poisat, Paul
- Date: 2001
- Subjects: Executives -- Rating of , Automobile industry and trade -- Management -- Case studies
- Language: English
- Type: Thesis , Masters , MTech (Human Resources Management)
- Identifier: vital:10871 , http://hdl.handle.net/10948/41 , Executives -- Rating of , Automobile industry and trade -- Management -- Case studies
- Description: This research addresses the problem of determining which managerial competencies first-line managers operating in a world class organisation should have. To achieve this objective a three-step method was followed. Firstly, an approach had to be found for the assessment of managerial competencies at the selected organisation involved in the research project. A comprehensive literature survey was conducted in an attempt to establish an approach and identify management competencies for first-line managers. Secondly, the recognition of prior learning (RPL) approaches appropriate to first-line managers were investigated and synthesized with the managerial competence approach of step one. Finally, the managerial competencies were assessed utilising the matrix of managerial competence instrument developed in accordance with the findings of the research. The information obtained from the literature study and from the candidates who were assessed resulted in various findings and recommendations. Using the matrix of managerial competence instrument, it was found that the majority of first-line managers at the organisation were competent. Notwithstanding this finding, a major recommendation is that the organisation should become more future and development orientated in its training strategy. Finally, the research project has created the foundation for the development of a managerial competency model at the selected organisation. Findings of the literature survey and development of the RPL instrument provide guidelines for future RPL initiatives, both at the selected organisation and at the Port Elizabeth Technikon.
- Full Text:
- Date Issued: 2001
- Authors: Poisat, Paul
- Date: 2001
- Subjects: Executives -- Rating of , Automobile industry and trade -- Management -- Case studies
- Language: English
- Type: Thesis , Masters , MTech (Human Resources Management)
- Identifier: vital:10871 , http://hdl.handle.net/10948/41 , Executives -- Rating of , Automobile industry and trade -- Management -- Case studies
- Description: This research addresses the problem of determining which managerial competencies first-line managers operating in a world class organisation should have. To achieve this objective a three-step method was followed. Firstly, an approach had to be found for the assessment of managerial competencies at the selected organisation involved in the research project. A comprehensive literature survey was conducted in an attempt to establish an approach and identify management competencies for first-line managers. Secondly, the recognition of prior learning (RPL) approaches appropriate to first-line managers were investigated and synthesized with the managerial competence approach of step one. Finally, the managerial competencies were assessed utilising the matrix of managerial competence instrument developed in accordance with the findings of the research. The information obtained from the literature study and from the candidates who were assessed resulted in various findings and recommendations. Using the matrix of managerial competence instrument, it was found that the majority of first-line managers at the organisation were competent. Notwithstanding this finding, a major recommendation is that the organisation should become more future and development orientated in its training strategy. Finally, the research project has created the foundation for the development of a managerial competency model at the selected organisation. Findings of the literature survey and development of the RPL instrument provide guidelines for future RPL initiatives, both at the selected organisation and at the Port Elizabeth Technikon.
- Full Text:
- Date Issued: 2001
The changing knowledge and expectations of public health nurses in a HIV/AIDS training programme for managers
- Authors: Harry, Karuna
- Date: 2001
- Subjects: HIV infections , HIV infections -- Nursing , HIV-positive persons -- Counseling of
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2986 , http://hdl.handle.net/10962/d1002495 , HIV infections , HIV infections -- Nursing , HIV-positive persons -- Counseling of
- Description: This research project examined the changing expectations and knowledge of Managers in the Department of Health who attended the Sexual Health Counselling Project offered by Rhodes University, East London, South Africa. These managers came from contexts in which the hierarchical medical model is firmly entrenched. The Sexual Health Counselling Project, drawing on theoretical principles from Narrative and other theories,presented a challenge to the standard management practices used by the managers. It also challenged how they dealt with clients. This research explored changes in expectations and knowledge prior to and during a two- week training course that the managers attended. A personal awareness and shift in knowledge occurred for many managers who examined their current practices. Some managers, who were firmly entrenched in the hierarchical model,found it difficult to change their ways of working.
- Full Text:
- Date Issued: 2001
- Authors: Harry, Karuna
- Date: 2001
- Subjects: HIV infections , HIV infections -- Nursing , HIV-positive persons -- Counseling of
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2986 , http://hdl.handle.net/10962/d1002495 , HIV infections , HIV infections -- Nursing , HIV-positive persons -- Counseling of
- Description: This research project examined the changing expectations and knowledge of Managers in the Department of Health who attended the Sexual Health Counselling Project offered by Rhodes University, East London, South Africa. These managers came from contexts in which the hierarchical medical model is firmly entrenched. The Sexual Health Counselling Project, drawing on theoretical principles from Narrative and other theories,presented a challenge to the standard management practices used by the managers. It also challenged how they dealt with clients. This research explored changes in expectations and knowledge prior to and during a two- week training course that the managers attended. A personal awareness and shift in knowledge occurred for many managers who examined their current practices. Some managers, who were firmly entrenched in the hierarchical model,found it difficult to change their ways of working.
- Full Text:
- Date Issued: 2001
The constitutional right of access to social security
- Authors: Govindjee, Avinash
- Date: 2001
- Subjects: Social security -- Law and legislation -- South Africa , South Africa -- Social policy
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11061 , http://hdl.handle.net/10948/280 , Social security -- Law and legislation -- South Africa , South Africa -- Social policy
- Description: The inclusion of the right of access to social security in the Constitution did not meet with wholehearted approval in South Africa. This right, however, is of vital importance for the future upliftment of the country. The present social security system is based upon a clear distinction between social assistance and social insurance. There is a gap in current social security provisions in that the unemployed middle aged individual is not covered. Unemployment itself is one of the greatest challenges obscuring the implementation of a comprehensive social security system. The Constitutional right is to have ‘access’ to social security and the amount of resources at the state’s disposal is directly related to increasing this right, although it is true that a number of available resources are misspent. The state must take reasonable legislative and other measures, within its available resources, to achieve the progressive realisation of the right of access to social security. The principles of solidarity and ubuntu must be cultivated so that national social development becomes a concern for all citizens. There are numerous problems facing South Africans in attaining the goal of access to social security – even if national social development does become a priority. Budgetary constraints, poverty, unemployment, HIV/Aids and foreigners are examples of these. By making social security a priority for everyone, existing ideas (almost all of which have merit) may be converted into long-term solutions for poverty and unemployment. Currently, numerous opportunities to salvage the situation are being overlooked as a result of the lack of a comprehensive and structured plan to better the access to social security. The constitutional right of access to social security is enforceable, although the jurisprudence in this field remains underdeveloped. Conditions are currently favourable, within the country and beyond its borders, for an imaginative and concerted attempt to be made to find potential solutions. It is possible for resources to be increased and for tax benefits to be incorporated for businesses which have the capacity to contribute. The issue of defence spending is controversial, but could hold the key to lowering unemployment. Should jobs be created, it is likely that they will initially be of a temporary nature. Consequently, provisions are needed to ensure some guarantee of income in the lacuna between when a job is lost and another found. Ultimately, one thing is certain: the constitutional right of access to social security will only be complete once the people who are recipients of this right make sacrifices and create corresponding duties for themselves to ensure that the next generation of inhabitants of this country are not facing similar problems. The state’s goal should be to ensure that the basic rights which all people enjoy in terms of the Constitution (in particular the other socio-economic rights) are guaranteed for the duration of their existence, even if the level of benefits received by such people is low.
- Full Text:
- Date Issued: 2001
- Authors: Govindjee, Avinash
- Date: 2001
- Subjects: Social security -- Law and legislation -- South Africa , South Africa -- Social policy
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11061 , http://hdl.handle.net/10948/280 , Social security -- Law and legislation -- South Africa , South Africa -- Social policy
- Description: The inclusion of the right of access to social security in the Constitution did not meet with wholehearted approval in South Africa. This right, however, is of vital importance for the future upliftment of the country. The present social security system is based upon a clear distinction between social assistance and social insurance. There is a gap in current social security provisions in that the unemployed middle aged individual is not covered. Unemployment itself is one of the greatest challenges obscuring the implementation of a comprehensive social security system. The Constitutional right is to have ‘access’ to social security and the amount of resources at the state’s disposal is directly related to increasing this right, although it is true that a number of available resources are misspent. The state must take reasonable legislative and other measures, within its available resources, to achieve the progressive realisation of the right of access to social security. The principles of solidarity and ubuntu must be cultivated so that national social development becomes a concern for all citizens. There are numerous problems facing South Africans in attaining the goal of access to social security – even if national social development does become a priority. Budgetary constraints, poverty, unemployment, HIV/Aids and foreigners are examples of these. By making social security a priority for everyone, existing ideas (almost all of which have merit) may be converted into long-term solutions for poverty and unemployment. Currently, numerous opportunities to salvage the situation are being overlooked as a result of the lack of a comprehensive and structured plan to better the access to social security. The constitutional right of access to social security is enforceable, although the jurisprudence in this field remains underdeveloped. Conditions are currently favourable, within the country and beyond its borders, for an imaginative and concerted attempt to be made to find potential solutions. It is possible for resources to be increased and for tax benefits to be incorporated for businesses which have the capacity to contribute. The issue of defence spending is controversial, but could hold the key to lowering unemployment. Should jobs be created, it is likely that they will initially be of a temporary nature. Consequently, provisions are needed to ensure some guarantee of income in the lacuna between when a job is lost and another found. Ultimately, one thing is certain: the constitutional right of access to social security will only be complete once the people who are recipients of this right make sacrifices and create corresponding duties for themselves to ensure that the next generation of inhabitants of this country are not facing similar problems. The state’s goal should be to ensure that the basic rights which all people enjoy in terms of the Constitution (in particular the other socio-economic rights) are guaranteed for the duration of their existence, even if the level of benefits received by such people is low.
- Full Text:
- Date Issued: 2001
The construction of 'farm killings' in the Eastern Province Herald: an ideological analysis of the Herald's farm killings' disclosure, August 1998
- Authors: Jacobs, Luzuko
- Date: 2001
- Subjects: Farm killings -- South Africa -- Eastern Cape Murder -- South Africa -- Eastern Cape Eastern Province Herald (Newspaper)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3436 , http://hdl.handle.net/10962/d1002890
- Description: This study examines the ideological inflection of the ‘farm killings’ discourse in the Eastern Province Herald articles published in August 1998. ‘Farm killings’ is a media frame which was applied to a spate of killings of people on the country’s farms since 1994. Heightened and sustained media attention on the ‘farm killings’ has lifted the phenomenon from the other ‘run-of-the-mill’ murder crimes, and located it firmly as a matter of public concern and a subject of a broad political and economic debate. In this study I investigate the media coverage of the ‘farm killings’ within the context of these debates. The cultural studies approach to the study of the media provides a fruitful theoretical framework within which this study is located. The ideological examination of the articles is done using the critical linguistics method - a brand of reflexive, interpretative style of analysis which enables a sustained examination of media texts within their social, cultural and historical context. This study’s conclusions pose a challenge to the ‘Fourth Estate’ role often claimed for the media. In particular, it denies that the Herald objectively, fairly and truthfully reflected the experience on the farms during the period of this study. Its main finding is that the newspaper instead, constructed a particular understanding of the killings characterised by subtle racism, bias and partiality.
- Full Text:
- Date Issued: 2001
- Authors: Jacobs, Luzuko
- Date: 2001
- Subjects: Farm killings -- South Africa -- Eastern Cape Murder -- South Africa -- Eastern Cape Eastern Province Herald (Newspaper)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3436 , http://hdl.handle.net/10962/d1002890
- Description: This study examines the ideological inflection of the ‘farm killings’ discourse in the Eastern Province Herald articles published in August 1998. ‘Farm killings’ is a media frame which was applied to a spate of killings of people on the country’s farms since 1994. Heightened and sustained media attention on the ‘farm killings’ has lifted the phenomenon from the other ‘run-of-the-mill’ murder crimes, and located it firmly as a matter of public concern and a subject of a broad political and economic debate. In this study I investigate the media coverage of the ‘farm killings’ within the context of these debates. The cultural studies approach to the study of the media provides a fruitful theoretical framework within which this study is located. The ideological examination of the articles is done using the critical linguistics method - a brand of reflexive, interpretative style of analysis which enables a sustained examination of media texts within their social, cultural and historical context. This study’s conclusions pose a challenge to the ‘Fourth Estate’ role often claimed for the media. In particular, it denies that the Herald objectively, fairly and truthfully reflected the experience on the farms during the period of this study. Its main finding is that the newspaper instead, constructed a particular understanding of the killings characterised by subtle racism, bias and partiality.
- Full Text:
- Date Issued: 2001
The control of a multi-variable industrial process, by means of intelligent technology
- Authors: Naidoo, Puramanathan
- Date: 2001
- Subjects: Fuzzy systems , Intelligent control systems
- Language: English
- Type: Thesis , Masters , MTech (Electrical Engineering)
- Identifier: vital:10813 , http://hdl.handle.net/10948/48 , Fuzzy systems , Intelligent control systems
- Description: Conventional control systems express control solutions by means of expressions, usually mathematically based. In order to completely express the control solution, a vast amount of data is required. In contrast, knowledge-based solutions require far less plant data and mathematical expression. This reduces development time proportionally. In addition, because this type of processing does not require involved calculations, processing speed is increased, since rule process is separate and all processes can be performed simultaneously. These results in improved product quality, better plant efficiency, simplified process, etc. Within this project, conventional PID control has already been implemented, with the control parameter adjustment and loop tuning being problematic. This is mainly due to a number of external parameters that affects the stability of the process. In maintaining a consistent temperature, for example, the steam flow rate varies, the hot well temperature varies, the ambient may temperature vary. Another contributing factor, the time delay, also affects the optimization of the system, due to the fact that temperature measurement is based on principle of absorption. The normal practice in industry to avoid an unstable control condition is to have an experienced operator to switch the controller to manual, and make adjustments. After obtaining the desired PV, the controller is switched back to automatic. This research project focuses on eliminating this time loss, by implementing a knowledge-based controller, for intelligent decision-making. A FLC design tool, which allows full interaction, whilst designing the control algorithm, was used to optimize the control system. The design tool executed on a PC is connected to a PLC, which in turn is successfully integrated into the process plant.
- Full Text:
- Date Issued: 2001
- Authors: Naidoo, Puramanathan
- Date: 2001
- Subjects: Fuzzy systems , Intelligent control systems
- Language: English
- Type: Thesis , Masters , MTech (Electrical Engineering)
- Identifier: vital:10813 , http://hdl.handle.net/10948/48 , Fuzzy systems , Intelligent control systems
- Description: Conventional control systems express control solutions by means of expressions, usually mathematically based. In order to completely express the control solution, a vast amount of data is required. In contrast, knowledge-based solutions require far less plant data and mathematical expression. This reduces development time proportionally. In addition, because this type of processing does not require involved calculations, processing speed is increased, since rule process is separate and all processes can be performed simultaneously. These results in improved product quality, better plant efficiency, simplified process, etc. Within this project, conventional PID control has already been implemented, with the control parameter adjustment and loop tuning being problematic. This is mainly due to a number of external parameters that affects the stability of the process. In maintaining a consistent temperature, for example, the steam flow rate varies, the hot well temperature varies, the ambient may temperature vary. Another contributing factor, the time delay, also affects the optimization of the system, due to the fact that temperature measurement is based on principle of absorption. The normal practice in industry to avoid an unstable control condition is to have an experienced operator to switch the controller to manual, and make adjustments. After obtaining the desired PV, the controller is switched back to automatic. This research project focuses on eliminating this time loss, by implementing a knowledge-based controller, for intelligent decision-making. A FLC design tool, which allows full interaction, whilst designing the control algorithm, was used to optimize the control system. The design tool executed on a PC is connected to a PLC, which in turn is successfully integrated into the process plant.
- Full Text:
- Date Issued: 2001
The determination of geomorphologically effective flows for selected eastern sea-Board Rivers in South Africa
- Authors: Dollar, Evan S J
- Date: 2001
- Subjects: Rivers--South Africa River channels Geomorphology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4824 , http://hdl.handle.net/10962/d1005499
- Description: In South Africa the need to protect and manage the national water resource has led to the development of the Reserve as a basic right under the National Water Act (1998). The Ecological Reserve relates to the quality and quantity of water necessary to protect the sustainable functioning of aquatic ecosystems. The geomorphological contribution to setting the Reserve has focussed on three groups of information requirements: the spatial and temporal availability of habitat, the maintenance of substratum characteristics, and the maintenance of channel form. This thesis focusses on the second and third information requirements. The thesis has attempted to achieve this by adding value to the theoretical and applied understanding of the magnitude and frequency of channel forming discharge for selected southern African rivers. Many of the eastern sea-board rivers are strongly influenced by bed rock in the channel perimeter, and by a highly variable hydrological regime. This has resulted in characteristic channel forms, with an active channel incised into a larger macro-channel being a common feature of eastern seaboard rivers. Within the active channel inset channel benches commonly occur. This alluvial architecture is used to provide clues as to the types of flows necessary to meet the Reserve. Three river basins are considered : the Mkomazi, Mhlathuze and Olifants. The Mkomazi is a relatively un-impacted perennial eastern-sea board river and forms the research component of the study. The Mhlathuze and Olifants rivers are highly regulated systems and form the application component of the study. Utilising synthesised daily hydrological data, bed material data, cross-sectional surveys, hydraulic data and relevant bed material transport equations, channel form was related to dominant discharge and effective discharge in an attempt to identify the magnitude and frequency offlows that can be considered to be ' effective'. Results from the Mkomazi River indicate that no single effective discharge exists, but rather that there is a range of effective discharges in the 5-0.1% range on the 1-day daily flow duration curves that are responsible for the bulk (>80%) of the bed material transport. Only large floods (termed 'reset'discharges) with average return periods of around 20 years generate sufficient stream power and shear stress to mobilise the entire bed. The macro-channel is thus maintained by the large ' reset' flood events, and the active channel is maintained both by the range of effective discharges and the ' reset 'discharges. These are the geomorphologically 'effective' flows. Results from the Mhlathuze River have indicated that the Goedertrouw Dam has had a considerable impact on the downstream channel morphology and bed material transport capacity and consequently the effective and dominant discharges. It has been suggested that the Mhlathuze River is now adjusting its channel geometry in sympathy with the regulated flow environment. Under present-day conditions it has been demonstrated that the total bed material load has been reduced by up to three times, but there has also been a clear change in the way in which the load has been distributed around the duration curve. Under present-day conditions, over 90% of the total bed material load is transported by the top 5% of the flows, whereas under virgin flow conditions 90% of the total bed material load was transported by the top 20% of the flows. For the Olifants River there appears to be no relationship between the estimated bankfull discharge and any hydrological statistic. The effective discharge flow class is in the 5-0.01% range on the 1-day daily flow duration curve. It has also been pointed out that even the highest flows simulated for the Olifants River do not generate sufficient energy to mobilise the entire bed. It is useful to consider the Olifants River as being adapted to a highly variable flow regime. It is erroneous to think of one ' effective' discharge, but rather a range of effective discharges are of significance. It has been argued that strong bed rock control and a highly variable flow regime in many southern African rivers accounts for the channel architecture, and that there is a need to develop an ' indigenous knowledge' in the management of southern African fluvial systems
- Full Text:
- Date Issued: 2001
- Authors: Dollar, Evan S J
- Date: 2001
- Subjects: Rivers--South Africa River channels Geomorphology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4824 , http://hdl.handle.net/10962/d1005499
- Description: In South Africa the need to protect and manage the national water resource has led to the development of the Reserve as a basic right under the National Water Act (1998). The Ecological Reserve relates to the quality and quantity of water necessary to protect the sustainable functioning of aquatic ecosystems. The geomorphological contribution to setting the Reserve has focussed on three groups of information requirements: the spatial and temporal availability of habitat, the maintenance of substratum characteristics, and the maintenance of channel form. This thesis focusses on the second and third information requirements. The thesis has attempted to achieve this by adding value to the theoretical and applied understanding of the magnitude and frequency of channel forming discharge for selected southern African rivers. Many of the eastern sea-board rivers are strongly influenced by bed rock in the channel perimeter, and by a highly variable hydrological regime. This has resulted in characteristic channel forms, with an active channel incised into a larger macro-channel being a common feature of eastern seaboard rivers. Within the active channel inset channel benches commonly occur. This alluvial architecture is used to provide clues as to the types of flows necessary to meet the Reserve. Three river basins are considered : the Mkomazi, Mhlathuze and Olifants. The Mkomazi is a relatively un-impacted perennial eastern-sea board river and forms the research component of the study. The Mhlathuze and Olifants rivers are highly regulated systems and form the application component of the study. Utilising synthesised daily hydrological data, bed material data, cross-sectional surveys, hydraulic data and relevant bed material transport equations, channel form was related to dominant discharge and effective discharge in an attempt to identify the magnitude and frequency offlows that can be considered to be ' effective'. Results from the Mkomazi River indicate that no single effective discharge exists, but rather that there is a range of effective discharges in the 5-0.1% range on the 1-day daily flow duration curves that are responsible for the bulk (>80%) of the bed material transport. Only large floods (termed 'reset'discharges) with average return periods of around 20 years generate sufficient stream power and shear stress to mobilise the entire bed. The macro-channel is thus maintained by the large ' reset' flood events, and the active channel is maintained both by the range of effective discharges and the ' reset 'discharges. These are the geomorphologically 'effective' flows. Results from the Mhlathuze River have indicated that the Goedertrouw Dam has had a considerable impact on the downstream channel morphology and bed material transport capacity and consequently the effective and dominant discharges. It has been suggested that the Mhlathuze River is now adjusting its channel geometry in sympathy with the regulated flow environment. Under present-day conditions it has been demonstrated that the total bed material load has been reduced by up to three times, but there has also been a clear change in the way in which the load has been distributed around the duration curve. Under present-day conditions, over 90% of the total bed material load is transported by the top 5% of the flows, whereas under virgin flow conditions 90% of the total bed material load was transported by the top 20% of the flows. For the Olifants River there appears to be no relationship between the estimated bankfull discharge and any hydrological statistic. The effective discharge flow class is in the 5-0.01% range on the 1-day daily flow duration curve. It has also been pointed out that even the highest flows simulated for the Olifants River do not generate sufficient energy to mobilise the entire bed. It is useful to consider the Olifants River as being adapted to a highly variable flow regime. It is erroneous to think of one ' effective' discharge, but rather a range of effective discharges are of significance. It has been argued that strong bed rock control and a highly variable flow regime in many southern African rivers accounts for the channel architecture, and that there is a need to develop an ' indigenous knowledge' in the management of southern African fluvial systems
- Full Text:
- Date Issued: 2001
The development and assessment of both a separate, once-daily modified release matrix formulation of metoprolol tartrate and a combination formulation with hydrochlorothiazide
- Authors: Arjun, Jessica
- Date: 2001
- Subjects: Metoprolol -- Controlled release , Chlorothiazide -- Controlled release , Diuretics , Hypertension -- Treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3742 , http://hdl.handle.net/10962/d1003220 , Metoprolol -- Controlled release , Chlorothiazide -- Controlled release , Diuretics , Hypertension -- Treatment
- Description: The use of controlled release dosage forms has increased significantly in recent years as they result in increased patient compliance and higher therapeutic efficiency. This research focused on the development of a once daily dosage form that could be used for the treatment of hypertension. Both a separate sustained release dosage of metoprolol tartrate and a combination dosage form that included both an immediate release hydrochlorothiazide and a sustained release metoprolol component, were developed and evaluated. A matrix tablet, consisting of an ethylcellulose ranulation of metoprolol tartrate compressed into a hydrophilic hydroxypropyl methylcellulose polymer matrix, effectively sustained metoprolol release over a 22-hour experimental period. A multiparticulate combination dosage form that consisted of six coated mini matrix tablets of metoprolol and a powder blend of hydrochlorothiazide packed into a gelatin capsule, displayed zero order release kinetics for metoprolol release over 22 hours (r2=0.9946). The release of hydrochlorothiazide was found to be comparable to that of a commercially available product tested. Differential Scanning Calorimetry was used to identify possible incompatibilities between MPTA and excipients initially, and long term stability testing was used to assess to behaviour of the dosage form. Dissolution testing of the dosage forms was performed using USP Apparatus III, which was found to be more discriminating between the batches assessed. Dissolution curves were evaluated for similarity and difference using f1 and f2 fit factors. Samples were analyzed using a high performance liquid chromatographic method that was developed and validated for the simultaneous determination of the compounds of interest. Various factors influencing drug release from the developed dosage forms were assessed and recommendations for further optimization of the formulation are made. Factors evaluated included the quantity of granulating fluid, matrix polymer content, drug load and process variables, including drying time and compression force. The influence of various coating levels on drug release was assessed and none of the levels assessed were found to adequately retarded drug release over a 22-hour period. Combinations of tablets coated to different levels allowed for the successful development of a sustained release metoprolol component, which could be included into the combination dosage form.
- Full Text:
- Date Issued: 2001
- Authors: Arjun, Jessica
- Date: 2001
- Subjects: Metoprolol -- Controlled release , Chlorothiazide -- Controlled release , Diuretics , Hypertension -- Treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3742 , http://hdl.handle.net/10962/d1003220 , Metoprolol -- Controlled release , Chlorothiazide -- Controlled release , Diuretics , Hypertension -- Treatment
- Description: The use of controlled release dosage forms has increased significantly in recent years as they result in increased patient compliance and higher therapeutic efficiency. This research focused on the development of a once daily dosage form that could be used for the treatment of hypertension. Both a separate sustained release dosage of metoprolol tartrate and a combination dosage form that included both an immediate release hydrochlorothiazide and a sustained release metoprolol component, were developed and evaluated. A matrix tablet, consisting of an ethylcellulose ranulation of metoprolol tartrate compressed into a hydrophilic hydroxypropyl methylcellulose polymer matrix, effectively sustained metoprolol release over a 22-hour experimental period. A multiparticulate combination dosage form that consisted of six coated mini matrix tablets of metoprolol and a powder blend of hydrochlorothiazide packed into a gelatin capsule, displayed zero order release kinetics for metoprolol release over 22 hours (r2=0.9946). The release of hydrochlorothiazide was found to be comparable to that of a commercially available product tested. Differential Scanning Calorimetry was used to identify possible incompatibilities between MPTA and excipients initially, and long term stability testing was used to assess to behaviour of the dosage form. Dissolution testing of the dosage forms was performed using USP Apparatus III, which was found to be more discriminating between the batches assessed. Dissolution curves were evaluated for similarity and difference using f1 and f2 fit factors. Samples were analyzed using a high performance liquid chromatographic method that was developed and validated for the simultaneous determination of the compounds of interest. Various factors influencing drug release from the developed dosage forms were assessed and recommendations for further optimization of the formulation are made. Factors evaluated included the quantity of granulating fluid, matrix polymer content, drug load and process variables, including drying time and compression force. The influence of various coating levels on drug release was assessed and none of the levels assessed were found to adequately retarded drug release over a 22-hour period. Combinations of tablets coated to different levels allowed for the successful development of a sustained release metoprolol component, which could be included into the combination dosage form.
- Full Text:
- Date Issued: 2001
The development and evaluation of procedures for the synthesis of phenolic ethers by Baeyer-Villiger oxidation
- Authors: Hoffmann, Petra
- Date: 2001
- Subjects: Ethers , Phenols
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10955 , http://hdl.handle.net/10948/51 , Ethers , Phenols
- Description: A novel preparative method has been discovered in our laboratories which produces hydroxy-substituted phenolic ethers in a simple one-pot process. Initially it was found that 4-hydroxyacetophenone, when oxidized in the presence of ammonium peroxydisulfate and concentrated sulfuric acid in methanol, resulted in 4- methoxyphenol as product in high yield. Being novel, no information about the method was available in the literature, and hence it was our task to study the reaction more extensively. The scope of the reaction was investigated in that different reagents and substrates, as well as alternative oxidants, catalysts and alcohols (or reagents which may be envisaged to behave similarly to alcohols) were used. The studies showed that 4- hydroxy-substituted benzaldehyde and acetophenone, vanillin, fuchsones and stilbenequinones as substrates all successfully afforded the phenolic ether. Other oxidants such as hydrogen peroxide, sodium perborate etc. also afforded the phenolic ether but were less effective. The use of other acids than sulfuric acid resulted in comparable or lower yields of the desired phenolic ether. When the use of alcohols or similar reagents was varied, it was found that methanol, ethanol, benzyl alcohol, allyl alcohol, but-3-en-1-ol, hex-5-en-1-ol and undec-10-en-1-ol all afforded the desired ethers in significant yields. In an investigation to determine how this method may be useful for industrial applications, it was observed that compounds such as 3,5-di-tert-butyl-4-hydroxysubstituted alkenyloxy phenols, having potential application as antioxidant precursors in the polymer industry, may be prepared. Results showed that the reaction became less efficient when the alkenyl chain length was increased. The use of different acids and oxidants, the change of the oxidant:substrate ratio and the addition of a potential lanthanide catalyst did not improve the yield of the desired ether. A mechanism for the reaction was proposed which involved an initial Baeyer-Villiger oxygen insertion step to afford an ester which was hydrolysed in situ to hydroquinone. The remaining oxidant was then involved in oxidizing some of the soformed hydroquinone to benzoquinone. It was then proposed that these two compounds, i.e., hydroquinone and benzoquinone, interacted with each other in solution, forming a charge-transfer complex. According to our proposal, the carbonyl group of the benzoquinone, when complexed with hydroquinone in solution, was then attacked by nucleophilic reagents such as alcohols. Etherification hence resulted as a consequence of this attack. A statistical experimental evaluation and optimization study was then performed which led to a system that produced the phenolic ether, 4-methoxyphenol, in an 86% yield. An analysis of the effects of the reaction parameters on the reaction showed that the reaction temperature and the oxidant:substrate ratio played a major role in deciding the effectiveness of the reaction, while the amount of substrate and acidic catalyst had a much smaller influence on the ether yields.
- Full Text:
- Date Issued: 2001
- Authors: Hoffmann, Petra
- Date: 2001
- Subjects: Ethers , Phenols
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10955 , http://hdl.handle.net/10948/51 , Ethers , Phenols
- Description: A novel preparative method has been discovered in our laboratories which produces hydroxy-substituted phenolic ethers in a simple one-pot process. Initially it was found that 4-hydroxyacetophenone, when oxidized in the presence of ammonium peroxydisulfate and concentrated sulfuric acid in methanol, resulted in 4- methoxyphenol as product in high yield. Being novel, no information about the method was available in the literature, and hence it was our task to study the reaction more extensively. The scope of the reaction was investigated in that different reagents and substrates, as well as alternative oxidants, catalysts and alcohols (or reagents which may be envisaged to behave similarly to alcohols) were used. The studies showed that 4- hydroxy-substituted benzaldehyde and acetophenone, vanillin, fuchsones and stilbenequinones as substrates all successfully afforded the phenolic ether. Other oxidants such as hydrogen peroxide, sodium perborate etc. also afforded the phenolic ether but were less effective. The use of other acids than sulfuric acid resulted in comparable or lower yields of the desired phenolic ether. When the use of alcohols or similar reagents was varied, it was found that methanol, ethanol, benzyl alcohol, allyl alcohol, but-3-en-1-ol, hex-5-en-1-ol and undec-10-en-1-ol all afforded the desired ethers in significant yields. In an investigation to determine how this method may be useful for industrial applications, it was observed that compounds such as 3,5-di-tert-butyl-4-hydroxysubstituted alkenyloxy phenols, having potential application as antioxidant precursors in the polymer industry, may be prepared. Results showed that the reaction became less efficient when the alkenyl chain length was increased. The use of different acids and oxidants, the change of the oxidant:substrate ratio and the addition of a potential lanthanide catalyst did not improve the yield of the desired ether. A mechanism for the reaction was proposed which involved an initial Baeyer-Villiger oxygen insertion step to afford an ester which was hydrolysed in situ to hydroquinone. The remaining oxidant was then involved in oxidizing some of the soformed hydroquinone to benzoquinone. It was then proposed that these two compounds, i.e., hydroquinone and benzoquinone, interacted with each other in solution, forming a charge-transfer complex. According to our proposal, the carbonyl group of the benzoquinone, when complexed with hydroquinone in solution, was then attacked by nucleophilic reagents such as alcohols. Etherification hence resulted as a consequence of this attack. A statistical experimental evaluation and optimization study was then performed which led to a system that produced the phenolic ether, 4-methoxyphenol, in an 86% yield. An analysis of the effects of the reaction parameters on the reaction showed that the reaction temperature and the oxidant:substrate ratio played a major role in deciding the effectiveness of the reaction, while the amount of substrate and acidic catalyst had a much smaller influence on the ether yields.
- Full Text:
- Date Issued: 2001
The development of a balanced scorecard for strategic planning in a frozen vegetable processing plant
- Authors: Du Plessis, Francois
- Date: 2001
- Subjects: Food industry and trade -- South Africa -- Management , Strategic planning
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10887 , http://hdl.handle.net/10948/52 , Food industry and trade -- South Africa -- Management , Strategic planning
- Description: This research investigated the development of a balanced scorecard for a frozen vegetable processing plant. The balanced scorecard can be utilised as a strategic management and performance measurement system. First, an overview of the balanced scorecard concept was presented. Its four perspectives, namely financial, customer, internal business process, and learning and growth were explained. Thereafter, the process of developing a balanced scorecard was outlined and the translation of a firm’s vision into measurable objectives and targets was discussed. Finally, the literature study evaluated the development of balanced scorecards by means of selected case studies. This included an analysis of the successes and failures of balanced scorecards in practice. The research methodology consisted of: (a) A literature study to determine a framework for developing a balanced scorecard. (b) Interviews and workshops to gather the primary data required to develop a balanced scorecard. The development of a balanced scorecard for a frozen vegetable processing plant using the findings from (a) and (b) above. The following recommendations were made: · Targets and action plans should be developed for the outstanding strategic objectives of the plant, and all key performance measurements should be formalised on key performance area documents. All role players should be involved in this process. · All employees must be exposed to, and understand the plant’s vision, mission statement and the purpose of the balanced scorecard. · All employees need to understand how their actions impact on other employees and the well-being of the plant. They must have set objectives and targets that can be measured. · To increase the chance of a successful scorecard implementation, regular feedback must be provided to all employees, and managers must hold people accountable for using the system.
- Full Text:
- Date Issued: 2001
- Authors: Du Plessis, Francois
- Date: 2001
- Subjects: Food industry and trade -- South Africa -- Management , Strategic planning
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10887 , http://hdl.handle.net/10948/52 , Food industry and trade -- South Africa -- Management , Strategic planning
- Description: This research investigated the development of a balanced scorecard for a frozen vegetable processing plant. The balanced scorecard can be utilised as a strategic management and performance measurement system. First, an overview of the balanced scorecard concept was presented. Its four perspectives, namely financial, customer, internal business process, and learning and growth were explained. Thereafter, the process of developing a balanced scorecard was outlined and the translation of a firm’s vision into measurable objectives and targets was discussed. Finally, the literature study evaluated the development of balanced scorecards by means of selected case studies. This included an analysis of the successes and failures of balanced scorecards in practice. The research methodology consisted of: (a) A literature study to determine a framework for developing a balanced scorecard. (b) Interviews and workshops to gather the primary data required to develop a balanced scorecard. The development of a balanced scorecard for a frozen vegetable processing plant using the findings from (a) and (b) above. The following recommendations were made: · Targets and action plans should be developed for the outstanding strategic objectives of the plant, and all key performance measurements should be formalised on key performance area documents. All role players should be involved in this process. · All employees must be exposed to, and understand the plant’s vision, mission statement and the purpose of the balanced scorecard. · All employees need to understand how their actions impact on other employees and the well-being of the plant. They must have set objectives and targets that can be measured. · To increase the chance of a successful scorecard implementation, regular feedback must be provided to all employees, and managers must hold people accountable for using the system.
- Full Text:
- Date Issued: 2001
The development of a model of factors promoting leadership effectiveness in the private hospitals of Afrox Healthcare in the Port Elizabeth area
- Authors: Bosch, Wouter Conrad
- Date: 2001
- Subjects: Leadership
- Language: English
- Type: Thesis , Masters , MTech (Management)
- Identifier: vital:10901 , http://hdl.handle.net/10948/53 , Leadership
- Description: Effective leadership is essential for the achievement of organisational success in the long term. Leadership is the central ingredient necessary for progress as well as for the development and survival of organisations, especially in a changing environment such as South Africa. In this study an evaluation of various leadership models was conducted and a model of factors promoting effective leadership has been developed and proposed. This model was then tested amongst managers in the Private Hospitals of Afrox Healthcare in the Port Elizabeth area. The following procedure was followed: Firstly, a literature study was undertaken to identify the various leadership approaches. Attention was mainly focused on the most recent or advanced approaches to leadership. Secondly, based on the most recent approaches to leadership, a model of factors promoting effective leadership has been developed and proposed. The key elements identified for effective leadership are contained in this model. Thirdly, an empirical study was conducted to test the proposed model of leadership. Lastly, the results of the empirical study were evaluated, conclusions were drawn and recommendations made, based on the information obtained from both the literature study and the empirical study. The model of factors of effective leadership that has been developed is a combination of : · Leader Behaviours, which includes the elements of vision, communication, planning and empowerment; · Follower Behaviours, consisting of identification with the leader and the leader’s vision, commitment, motivation and goal pursuit, as well as trust; and · Organisational Environmental factors, including organisational configuration, organisational structure and organisational culture. It is argued that when the factors contained in the model achieve synergy, leadership will be effective, leading to enhanced organisational performance and success.
- Full Text:
- Date Issued: 2001
- Authors: Bosch, Wouter Conrad
- Date: 2001
- Subjects: Leadership
- Language: English
- Type: Thesis , Masters , MTech (Management)
- Identifier: vital:10901 , http://hdl.handle.net/10948/53 , Leadership
- Description: Effective leadership is essential for the achievement of organisational success in the long term. Leadership is the central ingredient necessary for progress as well as for the development and survival of organisations, especially in a changing environment such as South Africa. In this study an evaluation of various leadership models was conducted and a model of factors promoting effective leadership has been developed and proposed. This model was then tested amongst managers in the Private Hospitals of Afrox Healthcare in the Port Elizabeth area. The following procedure was followed: Firstly, a literature study was undertaken to identify the various leadership approaches. Attention was mainly focused on the most recent or advanced approaches to leadership. Secondly, based on the most recent approaches to leadership, a model of factors promoting effective leadership has been developed and proposed. The key elements identified for effective leadership are contained in this model. Thirdly, an empirical study was conducted to test the proposed model of leadership. Lastly, the results of the empirical study were evaluated, conclusions were drawn and recommendations made, based on the information obtained from both the literature study and the empirical study. The model of factors of effective leadership that has been developed is a combination of : · Leader Behaviours, which includes the elements of vision, communication, planning and empowerment; · Follower Behaviours, consisting of identification with the leader and the leader’s vision, commitment, motivation and goal pursuit, as well as trust; and · Organisational Environmental factors, including organisational configuration, organisational structure and organisational culture. It is argued that when the factors contained in the model achieve synergy, leadership will be effective, leading to enhanced organisational performance and success.
- Full Text:
- Date Issued: 2001
The development of a model to effectively utilise computer mediated communication to support assessment in a virtual learning environment
- Authors: Pullen, Grant
- Date: 2001
- Subjects: Computer-assisted instruction , Students -- Rating of , Communication in education -- Data processing
- Language: English
- Type: Thesis , Masters , MTech (Information Technology)
- Identifier: vital:10795 , http://hdl.handle.net/10948/54 , Computer-assisted instruction , Students -- Rating of , Communication in education -- Data processing
- Description: Programming lecturers are faced with logistical problems associated with evaluating students’ assignments. This dissertation will discuss the problems associated with paper- and electronic-based submission and evaluation systems. Managing student assignments is thus an important issue and this dissertation investigates how the computer can be used to help in both the management of programming assignments and giving of feedback for those assignments. Computer Mediated Communication (CMC) technologies offer a technical solution for the submission of assignments. CMC technologies are therefore studied and their use in the educational sphere discussed. Information Security is another important feature that is needed when using CMC for assignment management. A guideline showing the different features that an assignment management and feedback system would need was developed. Current systems that offer some assignment management features were studied and evaluated according to the guideline. A model was developed for the management of programming assignments. The model addresses the problems of paper-based and previous electronic submission systems and includes the assessment of the assignments. The viability of the model was determined by building and testing a prototype based on the model’s specifications. The prototype was evaluated within a second year Visual Basic programming class. The evaluation determined that there were areas that needed improvement, however the feedback was generally positive.
- Full Text:
- Date Issued: 2001
- Authors: Pullen, Grant
- Date: 2001
- Subjects: Computer-assisted instruction , Students -- Rating of , Communication in education -- Data processing
- Language: English
- Type: Thesis , Masters , MTech (Information Technology)
- Identifier: vital:10795 , http://hdl.handle.net/10948/54 , Computer-assisted instruction , Students -- Rating of , Communication in education -- Data processing
- Description: Programming lecturers are faced with logistical problems associated with evaluating students’ assignments. This dissertation will discuss the problems associated with paper- and electronic-based submission and evaluation systems. Managing student assignments is thus an important issue and this dissertation investigates how the computer can be used to help in both the management of programming assignments and giving of feedback for those assignments. Computer Mediated Communication (CMC) technologies offer a technical solution for the submission of assignments. CMC technologies are therefore studied and their use in the educational sphere discussed. Information Security is another important feature that is needed when using CMC for assignment management. A guideline showing the different features that an assignment management and feedback system would need was developed. Current systems that offer some assignment management features were studied and evaluated according to the guideline. A model was developed for the management of programming assignments. The model addresses the problems of paper-based and previous electronic submission systems and includes the assessment of the assignments. The viability of the model was determined by building and testing a prototype based on the model’s specifications. The prototype was evaluated within a second year Visual Basic programming class. The evaluation determined that there were areas that needed improvement, however the feedback was generally positive.
- Full Text:
- Date Issued: 2001
The development of a scale to measure sexual orientation and an examination of its psychometric properties
- Authors: Heath, Lance Julian
- Date: 2001
- Subjects: Sexual orientation , Sexual orientation -- Research -- Psychological aspects , Psychometrics
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3145 , http://hdl.handle.net/10962/d1007408 , Sexual orientation , Sexual orientation -- Research -- Psychological aspects , Psychometrics
- Description: The purpose of the study was to develop a scale to measure sexual orientation and to examine its psychometric properties. Previous scales were critically examined and compared and the need for a scale which simultaneously measures same and opposite sex responsiveness independently, and accounts for dynamic changes over time, while testing a number of overt and covert dimensions of sexual orientations, was established. A 48-item scale was designed to tap self-reported intensity and frequency of Emotional Attachment, Sexual Fantasy, Sexual Attraction and Sexual Contact towards males and females in the Past, Present and Future. An initial study was conducted with 13 undergraduate university students of both genders, representing a variety of sexual orientations and nationalities, and qualitative feedback was obtained and utilized to make appropriate adjustments and refinements to the scale. The scale was then administered to 133 Rhodes University undergraduate psychology students to obtain quantitative data with regard to its internal structure. The scale was found to have a good internal consistency reliability Cronbach alpha coefficient of 0.8106. Existing sub-scales had lower alpha coefficients. Factor analysis, a form of construct validation, was performed and four factors emerged. These had very good internal consistency reliability alpha coefficients: Sexual Responsiveness to Females (0.9894), Sexual Responsiveness to Males (0.9741), Emotional Attachment to Females (0.8403) and Emotional Attachment to Males (0.8372). These factors were further statistically analysed to ascertain how they relate to one another and to the demographics of gender, age, relational status and sexual orientation identity. Future research will need to assess other forms of reliability and validity and focus on larger and more varied samples.
- Full Text:
- Date Issued: 2001
- Authors: Heath, Lance Julian
- Date: 2001
- Subjects: Sexual orientation , Sexual orientation -- Research -- Psychological aspects , Psychometrics
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3145 , http://hdl.handle.net/10962/d1007408 , Sexual orientation , Sexual orientation -- Research -- Psychological aspects , Psychometrics
- Description: The purpose of the study was to develop a scale to measure sexual orientation and to examine its psychometric properties. Previous scales were critically examined and compared and the need for a scale which simultaneously measures same and opposite sex responsiveness independently, and accounts for dynamic changes over time, while testing a number of overt and covert dimensions of sexual orientations, was established. A 48-item scale was designed to tap self-reported intensity and frequency of Emotional Attachment, Sexual Fantasy, Sexual Attraction and Sexual Contact towards males and females in the Past, Present and Future. An initial study was conducted with 13 undergraduate university students of both genders, representing a variety of sexual orientations and nationalities, and qualitative feedback was obtained and utilized to make appropriate adjustments and refinements to the scale. The scale was then administered to 133 Rhodes University undergraduate psychology students to obtain quantitative data with regard to its internal structure. The scale was found to have a good internal consistency reliability Cronbach alpha coefficient of 0.8106. Existing sub-scales had lower alpha coefficients. Factor analysis, a form of construct validation, was performed and four factors emerged. These had very good internal consistency reliability alpha coefficients: Sexual Responsiveness to Females (0.9894), Sexual Responsiveness to Males (0.9741), Emotional Attachment to Females (0.8403) and Emotional Attachment to Males (0.8372). These factors were further statistically analysed to ascertain how they relate to one another and to the demographics of gender, age, relational status and sexual orientation identity. Future research will need to assess other forms of reliability and validity and focus on larger and more varied samples.
- Full Text:
- Date Issued: 2001
The development of a technique to establish the security requirements of an organization
- Authors: Gerber, Mariana
- Date: 2001
- Subjects: Computer security -- Management , Electronic data processing departments -- Security measures , Businesses -- Data processing -- Security measures , Computers -- Access control
- Language: English
- Type: Thesis , Masters , MTech (Information Technology)
- Identifier: vital:10789 , http://hdl.handle.net/10948/89 , Computer security -- Management , Electronic data processing departments -- Security measures , Businesses -- Data processing -- Security measures , Computers -- Access control
- Description: To perform their business activities effectively, organizations rely heavily on the use of information (ISO/IEC TR 13335-2, 1996, p 1). Owens (1998) reiterates this by claiming that all organizations depend on information for their everyday operation and without it business will fail to operate (Owens, 1998, p 1-2). For an organization it means that if the right information is not available at the right time, it can make the difference between profit and loss or success and failure (Royds, 2000, p 2). Information is an asset and just like other important business assets within the organization, it has extreme value to an organization (BS 7799-1, 1999, p 1; Humphreys, Moses & Plate, 1998, p 8). For this reason it has become very important that business information is sufficiently protected. There are many different ways in which information can exist. Information can be printed or written on paper, stored electronically, transmitted electronically or by post, even spoken in conversation or any other way in which knowledge and ideas can be conveyed (URN 99/703, 1999, p. 2; Humphreys, Moses & Plate, 1998, p 8; URN 96/702, 1996, p 3).It is, therefore, critical to protect information, and to ensure that the security of IT (Information Technology) systems within organizations is properly managed. This requirement to protect information is even more important today, since many organizations are internally and externally connected by networks of IT systems (ISO/IEC TR 13335-2, 1996, p 1). Information security is therefore required to assist in the process of controlling and securing of information from accidental or malicious changes, deletions or unauthorized disclosure (Royds, 2000, p 2; URN 96/702, 1996, p 3). By preventing and minimizing the impact of security incidents, information security can ensure business continuity and reduce business damage (Owens, 1998, p 7). Information security in an organization can be regarded as a management opportunity and should become an integral part of the whole management activity of the organization. Obtaining commitment from management is therefore extremely important for effective information security. One way in which management can show their commitment to ensuring information security, is to adopt and enforce a security policy. A security policy ensures that people understand exactly what important role they play in securing information assets.
- Full Text:
- Date Issued: 2001
- Authors: Gerber, Mariana
- Date: 2001
- Subjects: Computer security -- Management , Electronic data processing departments -- Security measures , Businesses -- Data processing -- Security measures , Computers -- Access control
- Language: English
- Type: Thesis , Masters , MTech (Information Technology)
- Identifier: vital:10789 , http://hdl.handle.net/10948/89 , Computer security -- Management , Electronic data processing departments -- Security measures , Businesses -- Data processing -- Security measures , Computers -- Access control
- Description: To perform their business activities effectively, organizations rely heavily on the use of information (ISO/IEC TR 13335-2, 1996, p 1). Owens (1998) reiterates this by claiming that all organizations depend on information for their everyday operation and without it business will fail to operate (Owens, 1998, p 1-2). For an organization it means that if the right information is not available at the right time, it can make the difference between profit and loss or success and failure (Royds, 2000, p 2). Information is an asset and just like other important business assets within the organization, it has extreme value to an organization (BS 7799-1, 1999, p 1; Humphreys, Moses & Plate, 1998, p 8). For this reason it has become very important that business information is sufficiently protected. There are many different ways in which information can exist. Information can be printed or written on paper, stored electronically, transmitted electronically or by post, even spoken in conversation or any other way in which knowledge and ideas can be conveyed (URN 99/703, 1999, p. 2; Humphreys, Moses & Plate, 1998, p 8; URN 96/702, 1996, p 3).It is, therefore, critical to protect information, and to ensure that the security of IT (Information Technology) systems within organizations is properly managed. This requirement to protect information is even more important today, since many organizations are internally and externally connected by networks of IT systems (ISO/IEC TR 13335-2, 1996, p 1). Information security is therefore required to assist in the process of controlling and securing of information from accidental or malicious changes, deletions or unauthorized disclosure (Royds, 2000, p 2; URN 96/702, 1996, p 3). By preventing and minimizing the impact of security incidents, information security can ensure business continuity and reduce business damage (Owens, 1998, p 7). Information security in an organization can be regarded as a management opportunity and should become an integral part of the whole management activity of the organization. Obtaining commitment from management is therefore extremely important for effective information security. One way in which management can show their commitment to ensuring information security, is to adopt and enforce a security policy. A security policy ensures that people understand exactly what important role they play in securing information assets.
- Full Text:
- Date Issued: 2001
The development of the common fraction concept in grade three learners
- Authors: Fraser, Claire Anne
- Date: 2001
- Subjects: Mathematics -- Study and teaching (Elementary) Mathematics Problems, exercises, etc Fractions -- Study and teaching (Elementary)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1497 , http://hdl.handle.net/10962/d1003379
- Description: Over a period of nine months in 1999, a longitudinal teaching intervention was undertaken with Grade 3 learners in the Fort Beaufort district, Eastern Cape. Working in the interpretive paradigm, the intervention focussed on: - the development of the common fraction concept, - the relevance of the hierarchy of Murray and Olivier’s Four Levels of Development in common fractions and - whether learners’ informal knowledge could be utilised in developing this concept. Using the Problem-centred approach to teaching mathematics, problems set in reallife contexts were used as vehicles for learning. Learners were required to discuss, reflect and make sense of the mathematics they were doing. Participant observation, completed worksheets and unstructured interviews with learners, formed the primary method of data collection. Learners’ work was analysed and classified according to the method used and manner in which the solution was notated. Results showed that learners were able to achieve a significant degree of success in developing a stable common fraction concept. Learners were afforded opportunities to construct their own ideas and to develop a deeper understanding of the concept. Many methods used were based on their informal knowledge of sharing. Learners made sense of realistic problems using drawings, and invented their own procedures. Apart from Level One, Phase Three, all Murray and Olivier’s Levels of Development could be identified during the research. This study will provide educators with valuable information on how learners solve mathematical problems involving fractions and how informal knowledge can be used as a foundation on which to build.
- Full Text:
- Date Issued: 2001
- Authors: Fraser, Claire Anne
- Date: 2001
- Subjects: Mathematics -- Study and teaching (Elementary) Mathematics Problems, exercises, etc Fractions -- Study and teaching (Elementary)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1497 , http://hdl.handle.net/10962/d1003379
- Description: Over a period of nine months in 1999, a longitudinal teaching intervention was undertaken with Grade 3 learners in the Fort Beaufort district, Eastern Cape. Working in the interpretive paradigm, the intervention focussed on: - the development of the common fraction concept, - the relevance of the hierarchy of Murray and Olivier’s Four Levels of Development in common fractions and - whether learners’ informal knowledge could be utilised in developing this concept. Using the Problem-centred approach to teaching mathematics, problems set in reallife contexts were used as vehicles for learning. Learners were required to discuss, reflect and make sense of the mathematics they were doing. Participant observation, completed worksheets and unstructured interviews with learners, formed the primary method of data collection. Learners’ work was analysed and classified according to the method used and manner in which the solution was notated. Results showed that learners were able to achieve a significant degree of success in developing a stable common fraction concept. Learners were afforded opportunities to construct their own ideas and to develop a deeper understanding of the concept. Many methods used were based on their informal knowledge of sharing. Learners made sense of realistic problems using drawings, and invented their own procedures. Apart from Level One, Phase Three, all Murray and Olivier’s Levels of Development could be identified during the research. This study will provide educators with valuable information on how learners solve mathematical problems involving fractions and how informal knowledge can be used as a foundation on which to build.
- Full Text:
- Date Issued: 2001
The distinction between a contract of employment and a contract with an independent contractor
- Authors: Slater, Henry John
- Date: 2001
- Subjects: Labor contract -- South Africa , Independent contractors -- South Africa , Contracts -- South Africa -- Cases , Liability (Law) -- South Africa , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11060 , http://hdl.handle.net/10948/276 , Labor contract -- South Africa , Independent contractors -- South Africa , Contracts -- South Africa -- Cases , Liability (Law) -- South Africa , Labor laws and legislation -- South Africa
- Description: The purpose of this treatise was to determine the distinction between the contract of service (employment) and the contract of work (independent contractor). A comprehensive literary survey was undertaken so as to establish if such a distinction does indeed exist. A logical point of departure was to study the contract of service and determine how the employment relationship is established by it. It is also necessary to establish under what circumstances a contract may be terminated and what the rights and obligations of the parties to the contract were. The contract between the parties will determine remedies to the breach of contract or applicability of labour legislation. It is also necessary to establish the definition of an employee under various statutes so as to understand what remedies exist should rights be infringed upon. Statutes considered include the Constitution of the Republic of South Africa, Labour Relations Act, Basic Conditions of Employment Act, Employment Equity Act, Unemployment Insurance Act, Compensation for Occupational Injuries and Diseases Act, Skills Development Act and the Income Tax Act. The effect of insolvency of the employer on the employee is also discussed. Outsourcing has played a major role in the emergence of the independent contractor. This phenomenon is considered from the point of the employer in terms of the reasons for choosing the option of outsourcing and the associated risks. The employee perspective is also dealt with in terms of why an employee would change his/her employment status. The various tests historically applied to determine the status of a worker is also discussed. These include the control, organisation, dominant impression and economic tests. Currently the dominant impression test is the one that is being applied to determine the employment relationship. Extensive reference was made to case law. United States of America cases are referred to with specific reference to the 20 Factor Test applied by the Internal Revenue Service. South African case law is dealt wit in terms of enforcement of Bargaining Council agreements, commission-earning persons, payment for services rendered, the intention of the parties and the identity of the true employer. The emergence of the dependent contractor is also addressed. This form of worker normally falls outside of the protection of labour legislation and social security. Amendments have been proposed to various statutes to remedy the situation in South Africa. A final aspect that is dealt with is that of vicarious liability. The applicability of this aspect lies in the liability of the employer for damages inflicted by the employee.
- Full Text:
- Date Issued: 2001
- Authors: Slater, Henry John
- Date: 2001
- Subjects: Labor contract -- South Africa , Independent contractors -- South Africa , Contracts -- South Africa -- Cases , Liability (Law) -- South Africa , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11060 , http://hdl.handle.net/10948/276 , Labor contract -- South Africa , Independent contractors -- South Africa , Contracts -- South Africa -- Cases , Liability (Law) -- South Africa , Labor laws and legislation -- South Africa
- Description: The purpose of this treatise was to determine the distinction between the contract of service (employment) and the contract of work (independent contractor). A comprehensive literary survey was undertaken so as to establish if such a distinction does indeed exist. A logical point of departure was to study the contract of service and determine how the employment relationship is established by it. It is also necessary to establish under what circumstances a contract may be terminated and what the rights and obligations of the parties to the contract were. The contract between the parties will determine remedies to the breach of contract or applicability of labour legislation. It is also necessary to establish the definition of an employee under various statutes so as to understand what remedies exist should rights be infringed upon. Statutes considered include the Constitution of the Republic of South Africa, Labour Relations Act, Basic Conditions of Employment Act, Employment Equity Act, Unemployment Insurance Act, Compensation for Occupational Injuries and Diseases Act, Skills Development Act and the Income Tax Act. The effect of insolvency of the employer on the employee is also discussed. Outsourcing has played a major role in the emergence of the independent contractor. This phenomenon is considered from the point of the employer in terms of the reasons for choosing the option of outsourcing and the associated risks. The employee perspective is also dealt with in terms of why an employee would change his/her employment status. The various tests historically applied to determine the status of a worker is also discussed. These include the control, organisation, dominant impression and economic tests. Currently the dominant impression test is the one that is being applied to determine the employment relationship. Extensive reference was made to case law. United States of America cases are referred to with specific reference to the 20 Factor Test applied by the Internal Revenue Service. South African case law is dealt wit in terms of enforcement of Bargaining Council agreements, commission-earning persons, payment for services rendered, the intention of the parties and the identity of the true employer. The emergence of the dependent contractor is also addressed. This form of worker normally falls outside of the protection of labour legislation and social security. Amendments have been proposed to various statutes to remedy the situation in South Africa. A final aspect that is dealt with is that of vicarious liability. The applicability of this aspect lies in the liability of the employer for damages inflicted by the employee.
- Full Text:
- Date Issued: 2001
The ecology and physiology of the springhare (Pedetes capensis) in the Eastern Cape Province of South Africa
- Authors: Peinke, Dean Michael
- Date: 2001
- Subjects: Hares -- South Africa -- Eastern Cape Hares -- Breeding -- South Africa -- Eastern Cape Hares -- Ecology -- South Africa -- Eastern Cape Hares -- Physiology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5670 , http://hdl.handle.net/10962/d1005355
- Description: Springhare are large, bipedal, nocturnal, herbivorous, burrowing rodents that are found in arid and semi-arid parts of southern and eastern Africa. In this thesis I examine the general ecology, biology and physiology of these animals in the Eastern Cape Province of South Africa. An investigation of their distribution and activity in the study site showed that springhare exhibit a preference for flat, open, recently disturbed habitat that is dominated by the grass Cynodon dactylon and the sedge Cyperus esculentus. These two species constitute a major proportion of their diet. The impact of spring hare on chicory and grazing is also discussed. Nightly activity generally peaks soon after dark and decreases in the 2-4 hour period before sunrise. This pattern is, however, modified by moonlight. Springhare typically respond to moonlight by reducing aboveground activity, shifting their activity to dark moonless periods of the night, and by reducing their use of open space. Contrary to earlier reports, springhare utilise several different burrow systems spread over large areas. They regularly change burrow systems and seldom spend more than a few consecutive days in each. Springhare do not appear to defend territories but recently used burrows appear to be avoided by conspecifics. Males and females on average use a similar number of burrows, scattered over similar sized areas. Burrows are shown to provide a stable microclimate of moderate temperature and high humidity throughout the year. Reproduction is continuous and there is no synchronised breeding season. The ability to reproduce throughout the year is attributed primarily to their ability to utilise subterranean food stores. The overall reproductive strategy of springhare (a single young with long gestation and weaning) is unusual for a mammal of this size but may be linked to low levels of adult and juvenile mortality. Physiologically, springhare are reasonably well adapted to life in hot, arid environments. They produce a concentrated urine, exhibit a high tolerance to dehydration, are good osmoregulators capable of maintaining plasma volume, osmolality and ion balance over long periods of water deprivation, and are able to produce dry faeces. They are also good thermoregulators at low ambient temperatures, which are usually encountered at night, but are poor thermoregulators at high ambient temperatures, which they avoid behaviourally.
- Full Text:
- Date Issued: 2001
- Authors: Peinke, Dean Michael
- Date: 2001
- Subjects: Hares -- South Africa -- Eastern Cape Hares -- Breeding -- South Africa -- Eastern Cape Hares -- Ecology -- South Africa -- Eastern Cape Hares -- Physiology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5670 , http://hdl.handle.net/10962/d1005355
- Description: Springhare are large, bipedal, nocturnal, herbivorous, burrowing rodents that are found in arid and semi-arid parts of southern and eastern Africa. In this thesis I examine the general ecology, biology and physiology of these animals in the Eastern Cape Province of South Africa. An investigation of their distribution and activity in the study site showed that springhare exhibit a preference for flat, open, recently disturbed habitat that is dominated by the grass Cynodon dactylon and the sedge Cyperus esculentus. These two species constitute a major proportion of their diet. The impact of spring hare on chicory and grazing is also discussed. Nightly activity generally peaks soon after dark and decreases in the 2-4 hour period before sunrise. This pattern is, however, modified by moonlight. Springhare typically respond to moonlight by reducing aboveground activity, shifting their activity to dark moonless periods of the night, and by reducing their use of open space. Contrary to earlier reports, springhare utilise several different burrow systems spread over large areas. They regularly change burrow systems and seldom spend more than a few consecutive days in each. Springhare do not appear to defend territories but recently used burrows appear to be avoided by conspecifics. Males and females on average use a similar number of burrows, scattered over similar sized areas. Burrows are shown to provide a stable microclimate of moderate temperature and high humidity throughout the year. Reproduction is continuous and there is no synchronised breeding season. The ability to reproduce throughout the year is attributed primarily to their ability to utilise subterranean food stores. The overall reproductive strategy of springhare (a single young with long gestation and weaning) is unusual for a mammal of this size but may be linked to low levels of adult and juvenile mortality. Physiologically, springhare are reasonably well adapted to life in hot, arid environments. They produce a concentrated urine, exhibit a high tolerance to dehydration, are good osmoregulators capable of maintaining plasma volume, osmolality and ion balance over long periods of water deprivation, and are able to produce dry faeces. They are also good thermoregulators at low ambient temperatures, which are usually encountered at night, but are poor thermoregulators at high ambient temperatures, which they avoid behaviourally.
- Full Text:
- Date Issued: 2001