A study of the factors influencing the success of internet marketing in small South African tourism businesses
- Authors: Elliott, Roger Michael
- Date: 2005
- Subjects: Tourism -- South Africa -- Management , Small business -- South Africa -- Management , Internet marketing -- South Africa , Strategic planning , Marketing -- Management , Communication in management
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1204 , http://hdl.handle.net/10962/d1016252
- Description: The tourism sector has been identified as an industry that has the potential to make a substantial contribution to job creation, economic growth, and redressing past imbalances in South Africa as it has been recognised as an underexploited sector with considerable potential for growth. The majority of tourism enterprises fall within the definition of small businesses, which have been identified as the most appropriate enterprises through which the economic challenges facing South Africa can be addressed. Small businesses differ from their larger counterparts not only in terms of size, but also in regard to access to resources and marketing expertise. Not surprisingly, one of the issues identified as preventing this sector from reaching its full potential is access to markets. The focus of this study is to identify the primary factors driving the success of the use of the Internet for marketing in small businesses operating in the tourism sector in South Africa. If these factors can be identified, this will allow existing and emerging small businesses to access markets and retain customers more easily leading to a proliferation of these enterprises. A theoretical model was formulated from the literature in which the factors influencing the success of Internet marketing were identified. These factors can broadly be divided into generic (marketing or management) factors and Internet specific factors. The technological aspects of the Internet were not ignored, but regarded as a resource to be managed rather than an autonomous source of competitive advantage. This model was tested by making use of a large-scale empirical study. Convenience sampling was used and the data was collected from small tourism businesses (that is businesses with fewer than 100 employees) in the Western Cape, Eastern Cape and KwaZulu-Natal provinces of South Africa. The factors were identified using exploratory factor analysis and the Cronbach alpha coefficients were assessed to confirm the reliability of these scales. Structural equation modelling was used as the principal mode of statistical analysis to measure the relationships amongst the variables in the model proposed in this study. A correlation analysis was used to measure the impact of marketing objectives on the success of Internet marketing. The primary determinants of the success of Internet marketing in small businesses operating in the tow-ism sector in South Africa were identified by the empirical study as: Product champion Links Alliances Owner-manager knowledge Entrepreneurial orientation Owner-manager vision Customer orientation Marketing objectives Interestingly, one factor, Strategic planning, recorded a negative influence on the success of Internet marketing. This is possibly because the owner-manager felt that this was a redundant exercise given the dominant and pervasive influence of the owner-manager in all spheres of the business. Nevertheless, if small tourism firms consider the factors identified in this thesis as essential aspects in the use of the Internet for marketing, this will allow them to overcome one of the biggest hurdles to their prosperity, namely, the access to markets.
- Full Text:
- Date Issued: 2005
- Authors: Elliott, Roger Michael
- Date: 2005
- Subjects: Tourism -- South Africa -- Management , Small business -- South Africa -- Management , Internet marketing -- South Africa , Strategic planning , Marketing -- Management , Communication in management
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1204 , http://hdl.handle.net/10962/d1016252
- Description: The tourism sector has been identified as an industry that has the potential to make a substantial contribution to job creation, economic growth, and redressing past imbalances in South Africa as it has been recognised as an underexploited sector with considerable potential for growth. The majority of tourism enterprises fall within the definition of small businesses, which have been identified as the most appropriate enterprises through which the economic challenges facing South Africa can be addressed. Small businesses differ from their larger counterparts not only in terms of size, but also in regard to access to resources and marketing expertise. Not surprisingly, one of the issues identified as preventing this sector from reaching its full potential is access to markets. The focus of this study is to identify the primary factors driving the success of the use of the Internet for marketing in small businesses operating in the tourism sector in South Africa. If these factors can be identified, this will allow existing and emerging small businesses to access markets and retain customers more easily leading to a proliferation of these enterprises. A theoretical model was formulated from the literature in which the factors influencing the success of Internet marketing were identified. These factors can broadly be divided into generic (marketing or management) factors and Internet specific factors. The technological aspects of the Internet were not ignored, but regarded as a resource to be managed rather than an autonomous source of competitive advantage. This model was tested by making use of a large-scale empirical study. Convenience sampling was used and the data was collected from small tourism businesses (that is businesses with fewer than 100 employees) in the Western Cape, Eastern Cape and KwaZulu-Natal provinces of South Africa. The factors were identified using exploratory factor analysis and the Cronbach alpha coefficients were assessed to confirm the reliability of these scales. Structural equation modelling was used as the principal mode of statistical analysis to measure the relationships amongst the variables in the model proposed in this study. A correlation analysis was used to measure the impact of marketing objectives on the success of Internet marketing. The primary determinants of the success of Internet marketing in small businesses operating in the tow-ism sector in South Africa were identified by the empirical study as: Product champion Links Alliances Owner-manager knowledge Entrepreneurial orientation Owner-manager vision Customer orientation Marketing objectives Interestingly, one factor, Strategic planning, recorded a negative influence on the success of Internet marketing. This is possibly because the owner-manager felt that this was a redundant exercise given the dominant and pervasive influence of the owner-manager in all spheres of the business. Nevertheless, if small tourism firms consider the factors identified in this thesis as essential aspects in the use of the Internet for marketing, this will allow them to overcome one of the biggest hurdles to their prosperity, namely, the access to markets.
- Full Text:
- Date Issued: 2005
Biological removal of nitrogen species from metal-processing wastewater
- Kasia, J M, Duncan, J R, Burgess, Jo E
- Authors: Kasia, J M , Duncan, J R , Burgess, Jo E
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6482 , http://hdl.handle.net/10962/d1006256
- Description: Although several nitrification/denitrification processes are established for the removal of ammonia and nitrate from municipal and industrial wastewaters, there are few reported results on the removal of these ions from metal-processing and finishing wastewaters. Unlike municipal wastewater, there is very little organic content in metal-processing wastewaters. Sources of ammonia and nitrate in the wastewater include the use of ammonium-nitrate-fuel oil as a blasting agent, and the use of other nitrogen-containing reagents during processing. The objective of this work was to investigate a biological process for the removal of nitrogenous compounds from real metal-processing wastewater. The system comprised an aerobic continuously stirred tank reactor (CSTR) followed by an anaerobic packed column and was run using real wastewater from a metal-processing operation. The system was inoculated using humus sludge from a municipal trickling filter and a period of approximately four weeks was required for a denitrifying biofilm to develop. Results showed that ammonia removal occurred readily in the CSTR while nitrite oxidation was slower to develop. The CSTR was found to be suitable for ammonia oxidation; up to 89% ammonia removal was achieved. By employing an integrated process comprising nitrification and denitrification, high ammonia removal efficiencies can be obtained. An effluent that is low in ammonia can be obtained with this system with additional carbon introduced after the CSTR. The gravel-packed column reactor was found to be unsuitable for the removal of nitrate in the configuration used (maximum 15% removal efficiency). The critical parameters for denitrification are nitrate concentration, temperature, influent flow rate and mean cell retention time. Nitrate removal did not meet the expectations projected by previous authors' work using synthetic wastewater.
- Full Text:
- Date Issued: 2005
- Authors: Kasia, J M , Duncan, J R , Burgess, Jo E
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6482 , http://hdl.handle.net/10962/d1006256
- Description: Although several nitrification/denitrification processes are established for the removal of ammonia and nitrate from municipal and industrial wastewaters, there are few reported results on the removal of these ions from metal-processing and finishing wastewaters. Unlike municipal wastewater, there is very little organic content in metal-processing wastewaters. Sources of ammonia and nitrate in the wastewater include the use of ammonium-nitrate-fuel oil as a blasting agent, and the use of other nitrogen-containing reagents during processing. The objective of this work was to investigate a biological process for the removal of nitrogenous compounds from real metal-processing wastewater. The system comprised an aerobic continuously stirred tank reactor (CSTR) followed by an anaerobic packed column and was run using real wastewater from a metal-processing operation. The system was inoculated using humus sludge from a municipal trickling filter and a period of approximately four weeks was required for a denitrifying biofilm to develop. Results showed that ammonia removal occurred readily in the CSTR while nitrite oxidation was slower to develop. The CSTR was found to be suitable for ammonia oxidation; up to 89% ammonia removal was achieved. By employing an integrated process comprising nitrification and denitrification, high ammonia removal efficiencies can be obtained. An effluent that is low in ammonia can be obtained with this system with additional carbon introduced after the CSTR. The gravel-packed column reactor was found to be unsuitable for the removal of nitrate in the configuration used (maximum 15% removal efficiency). The critical parameters for denitrification are nitrate concentration, temperature, influent flow rate and mean cell retention time. Nitrate removal did not meet the expectations projected by previous authors' work using synthetic wastewater.
- Full Text:
- Date Issued: 2005
Metalorganic vapour phase epitaxial growth and characterisation of Sb-based semiconductors
- Authors: Vankova, Viera
- Date: 2005
- Subjects: Compound semiconductors , Epitaxy , Organometallic compounds , Metal organic chemical vapor deposition
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10548 , http://hdl.handle.net/10948/d1019678
- Description: This study focuses on the growth and characterization of epitaxial InAs and InAs1-xSbx. Layers are grown on InAs, GaAs and GaSb substrates by metalorganic vapour phase epitaxy, using trimethylindium, trimethylantimony and arsine as precursors. The growth parameters (V/III ratio, Sb vapour phase compositions) are varied in the temperature range from 500 ºC to 700 ºC, in order to study the influence of these parameters on the structural, optical and electrical properties of the materials. The layers were assessed by X-ray diffraction, electron and optical microscopy, photoluminescence and Hall measurements. Furthermore, the influence of hydrogenation and annealing on the electrical and optical properties of GaSb was investigated. It is shown that the growth temperature and the V/III ratio play a vital role in the resulting surface morphology of homoepitaxial and heteroepitaxial InAs layers. Growth at low temperatures is found to promote three-dimensional growth in both cases, with improvements in the surface morphologies observed for higher growth temperatures. All the investigated epilayers are n-type. It is shown that the electrical properties of heteroepitaxial InAs epilayers are complicated by a competition between bulk conduction and conduction due to a surface accumulation and an interface layer. The low temperature photoluminescence spectra of homoepitaxial InAs are dominated by two transitions. These are identified as band-to-band/excitonic and donor-acceptor recombination. The incorporation efficiency of antimony (Sb) into InAs1-xSbx is dependent on the growth temperature and the V/III ratio. Under the growth conditions used in this study, the incorporation efficiency of Sb is controlled by the thermal stability of the two constituent binaries (i.e. InAs and InSb). Changes in the low temperature photoluminescence spectra are detected with increasing x. From temperature and laser power dependent measurements, the highest energy line is attributed to band-to-band/excitonic recombination, while the peak appearing approximately 15 meV below this line is assigned to donor-acceptor recombination. The origin of an additional “moving” peak observed for higher Sb mole fraction x is tentatively attributed to quasi-donor-acceptor-recombination, arising from increased impurity/defect concentrations and a higher compensation ratio in the material. However, the unusual behaviour of this peak may also be ascribed to the presence of some degree of ordering in InAsSb. The exposure of a semiconductor to a hydrogen plasma usually leads to the passivation of shallow and deep centres, thereby removing their electrical and optical activity. In this study, the passivation and thermal stability of the native acceptor in p-type GaSb is also investigated. It is shown that this acceptor can be passivated, where after improvements in the electrical and optical properties of GaSb are observed. Upon annealing the passivated samples above 300 °C, the acceptor is reactivated.
- Full Text:
- Date Issued: 2005
- Authors: Vankova, Viera
- Date: 2005
- Subjects: Compound semiconductors , Epitaxy , Organometallic compounds , Metal organic chemical vapor deposition
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10548 , http://hdl.handle.net/10948/d1019678
- Description: This study focuses on the growth and characterization of epitaxial InAs and InAs1-xSbx. Layers are grown on InAs, GaAs and GaSb substrates by metalorganic vapour phase epitaxy, using trimethylindium, trimethylantimony and arsine as precursors. The growth parameters (V/III ratio, Sb vapour phase compositions) are varied in the temperature range from 500 ºC to 700 ºC, in order to study the influence of these parameters on the structural, optical and electrical properties of the materials. The layers were assessed by X-ray diffraction, electron and optical microscopy, photoluminescence and Hall measurements. Furthermore, the influence of hydrogenation and annealing on the electrical and optical properties of GaSb was investigated. It is shown that the growth temperature and the V/III ratio play a vital role in the resulting surface morphology of homoepitaxial and heteroepitaxial InAs layers. Growth at low temperatures is found to promote three-dimensional growth in both cases, with improvements in the surface morphologies observed for higher growth temperatures. All the investigated epilayers are n-type. It is shown that the electrical properties of heteroepitaxial InAs epilayers are complicated by a competition between bulk conduction and conduction due to a surface accumulation and an interface layer. The low temperature photoluminescence spectra of homoepitaxial InAs are dominated by two transitions. These are identified as band-to-band/excitonic and donor-acceptor recombination. The incorporation efficiency of antimony (Sb) into InAs1-xSbx is dependent on the growth temperature and the V/III ratio. Under the growth conditions used in this study, the incorporation efficiency of Sb is controlled by the thermal stability of the two constituent binaries (i.e. InAs and InSb). Changes in the low temperature photoluminescence spectra are detected with increasing x. From temperature and laser power dependent measurements, the highest energy line is attributed to band-to-band/excitonic recombination, while the peak appearing approximately 15 meV below this line is assigned to donor-acceptor recombination. The origin of an additional “moving” peak observed for higher Sb mole fraction x is tentatively attributed to quasi-donor-acceptor-recombination, arising from increased impurity/defect concentrations and a higher compensation ratio in the material. However, the unusual behaviour of this peak may also be ascribed to the presence of some degree of ordering in InAsSb. The exposure of a semiconductor to a hydrogen plasma usually leads to the passivation of shallow and deep centres, thereby removing their electrical and optical activity. In this study, the passivation and thermal stability of the native acceptor in p-type GaSb is also investigated. It is shown that this acceptor can be passivated, where after improvements in the electrical and optical properties of GaSb are observed. Upon annealing the passivated samples above 300 °C, the acceptor is reactivated.
- Full Text:
- Date Issued: 2005
Motopomo: the historical-theoretical background to contemporary graphic design practices
- Authors: Economou, Inge
- Date: 2005
- Subjects: Graphic arts , Graphic arts -- 20th century , Modernism (Art)
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10764 , http://hdl.handle.net/10948/179 , Graphic arts , Graphic arts -- 20th century , Modernism (Art)
- Description: This study proposes to illustrate that the twentieth century passage from modernity to postmodernity, with its induction of socio-cultural development and attitudinal change, exists as a fundamental means of informing the character of contemporary graphic design practice1. Today, in contrast to the intentions of this study, many appraisals of graphic design work would seem to place too much emphasis on the analyses and evaluation of the stylistic character of creative practices and not enough on the theoretical, historical and attitudinal issues surrounding them. As such, this study attempts to reveal the meaning and moreover the relevance of philosophical, social, cultural and critical theory for contemporary, postmodern graphic design practices. This is done in order to provide graphic designers with a reflective awareness of the structure of the cultural context within which they work, and takes into account twentieth century cultural theory and twentieth century, western graphic design practice, within the framework of the passage from modernity to postmodernity.
- Full Text:
- Date Issued: 2005
- Authors: Economou, Inge
- Date: 2005
- Subjects: Graphic arts , Graphic arts -- 20th century , Modernism (Art)
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10764 , http://hdl.handle.net/10948/179 , Graphic arts , Graphic arts -- 20th century , Modernism (Art)
- Description: This study proposes to illustrate that the twentieth century passage from modernity to postmodernity, with its induction of socio-cultural development and attitudinal change, exists as a fundamental means of informing the character of contemporary graphic design practice1. Today, in contrast to the intentions of this study, many appraisals of graphic design work would seem to place too much emphasis on the analyses and evaluation of the stylistic character of creative practices and not enough on the theoretical, historical and attitudinal issues surrounding them. As such, this study attempts to reveal the meaning and moreover the relevance of philosophical, social, cultural and critical theory for contemporary, postmodern graphic design practices. This is done in order to provide graphic designers with a reflective awareness of the structure of the cultural context within which they work, and takes into account twentieth century cultural theory and twentieth century, western graphic design practice, within the framework of the passage from modernity to postmodernity.
- Full Text:
- Date Issued: 2005
An evaluation of whether the management practices of four companies (representing the printing industry in Bulawayo, Zimbabwe) have affected their profitability and success in the period 2003-2004
- Authors: Farren, Sean Michael
- Date: 2005
- Subjects: Printing industry -- Zimbabwe Organization change -- Zimbabwe Success in business -- Zimbabwe Management -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:817 , http://hdl.handle.net/10962/d1007926
- Description: Nohria, Joyce and Roberson, a trio of academics in the United States, wrote an article in the July issue of the Harvard Business Review in 2003 entitled "What Really Works". For several years they had studied the management practices of 160 companies in the United States with a view to determining what made certain companies consistently successful. They found that the most profitable companies in their study were not successful because they utilised the latest management tools and techniques, but rather that they had a strong grasp of business basics. Companies outperformed their industrial peers, because they excelled at what they called the four primary management practices - Strategy, Execution, Culture and Structure. These practices were supplemented by a proficiency in any two out of four secondary practices - Talent, Innovation, Leadership and Mergers and Partnerships. They called this winning combination the 4 + 2 Formula for business success. The purpose of this thesis is to determine whether competence in these management practices applies in the Third World. The study will concentrate on four companies representing the printing industry in Bulawayo, Zimbabwe. Zimbabwean companies are faced with a number of unusual obstacles that do not exist in First World free market economies. This study will attempt to examine the nature of the obstacles faced and how each company deals with them. It will determine whether the management practices outlined by Nohria et ai, are valued to the same degree in the Zimbabwean context, and how far they contribute to profitability.Because of the pace of change in Zimbabwe, the research will focus on the period 2003 - 2004 and evaluate another management practice - change management. The forces of change can often be so radically negative, that if companies are not adequately prepared, they may face imminent collapse. Change management, the process of anticipating, reacting to and driving forces of change, has become a vital competency. Without it, the prospects of profitability and success in the Zimbabwean environment are slim. For this reason, this management practice will be given the same focus as those eight discussed by Nohria et al.
- Full Text:
- Date Issued: 2005
- Authors: Farren, Sean Michael
- Date: 2005
- Subjects: Printing industry -- Zimbabwe Organization change -- Zimbabwe Success in business -- Zimbabwe Management -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:817 , http://hdl.handle.net/10962/d1007926
- Description: Nohria, Joyce and Roberson, a trio of academics in the United States, wrote an article in the July issue of the Harvard Business Review in 2003 entitled "What Really Works". For several years they had studied the management practices of 160 companies in the United States with a view to determining what made certain companies consistently successful. They found that the most profitable companies in their study were not successful because they utilised the latest management tools and techniques, but rather that they had a strong grasp of business basics. Companies outperformed their industrial peers, because they excelled at what they called the four primary management practices - Strategy, Execution, Culture and Structure. These practices were supplemented by a proficiency in any two out of four secondary practices - Talent, Innovation, Leadership and Mergers and Partnerships. They called this winning combination the 4 + 2 Formula for business success. The purpose of this thesis is to determine whether competence in these management practices applies in the Third World. The study will concentrate on four companies representing the printing industry in Bulawayo, Zimbabwe. Zimbabwean companies are faced with a number of unusual obstacles that do not exist in First World free market economies. This study will attempt to examine the nature of the obstacles faced and how each company deals with them. It will determine whether the management practices outlined by Nohria et ai, are valued to the same degree in the Zimbabwean context, and how far they contribute to profitability.Because of the pace of change in Zimbabwe, the research will focus on the period 2003 - 2004 and evaluate another management practice - change management. The forces of change can often be so radically negative, that if companies are not adequately prepared, they may face imminent collapse. Change management, the process of anticipating, reacting to and driving forces of change, has become a vital competency. Without it, the prospects of profitability and success in the Zimbabwean environment are slim. For this reason, this management practice will be given the same focus as those eight discussed by Nohria et al.
- Full Text:
- Date Issued: 2005
The development of independent contractors within the Working for Water Programme over a twenty-four month period : a programme evaluation : Western region, Eastern Cape
- Authors: Knipe, Andrew
- Date: 2005
- Subjects: Working for Water Programme Contractors -- South Africa Construction contracts -- South Africa Business enterprises, Black -- South Africa Employee empowerment -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:799 , http://hdl.handle.net/10962/d1004916
- Description: This research is concerned with the development of independent contractors within the Working for Water Programme over a twenty-four month period. The meaningful participation of previously disadvantaged South Africans fall within the ambit of black economic empowerment. The Government Gazette (1997: No. 1820) defines black economic empowerment as a deliberate programme to achieve the meaningful participation of disadvantaged South Africans in the mainstream economy as managers, owners of capital and employees. The purpose of this research was to evaluate the contractors within the Western Region of the Eastern Cape, in order to assess how they have developed as independent contractors within the developmental framework provided by the Working for Water Programme. This developmental framework takes place over a 462-day period or roughly 24 months. The evaluation aimed to determine whether the two-year development period sufficiently prepared contractors for competition in the open market and if contractors had acquired the necessary skills to run a successful business. A formative programme evaluation was used as a tool of analysis to identify areas of weakness and establish priorities for improvement. A qualitative research approach was followed, guided by an adapted version of the Context, Input, Process and Product approach to evaluation (Parlett and Hamilton cited in Calder, 1995, p.25). Using structured interviews comprising of closed and open ended questions, data was gathered from thirty contractors, five managers and one Senior Executive Officer within the Western Region of the Eastern Cape. An interview was also conducted with the Regional Programme leader of the Eastern Cape. Further data collection techniques included documentary research. Data was analysed using qualitative data analysis techniques described by Thorne (1997, p.118), as relying on inductive reasoning to interpret and structure the meanings that can be derived from the data. Passages of interest were marked so that the data could be reduced to a manageable size as described by Seidman (1991, p.91-1 01) and various categories were developed that had commonalties and thematic connections. The Working for Water Programme aims to exit contractors successfully after a twenty-four month developmental period. The Working for Water Programme has formalised its development framework through a training matrix in which the required training at contractor level is outlined. The finding of the research is that the current contractor development programme do not adequately prepare contractors for independence and entrepreneurship in a competitive market. There is no co-ordinated development of predetermined skills. Contractors are not able to articulate what their plans are after exit from the WFW Programme. No concrete evidence of actively pursuing alternative contract opportunities was evident from contractors who were about to exit the Programme and there is no person to champion the cause of meaningful post exit opportunities. The main recommendations from this research are that contractors be selected via an application system rather that appointment through steering committees. Selected contractors must be medically fit and at least have a matriculation certificate. Contractors should be assessed on a 6-monthly basis and contractors not achieving a minimum competency level must be removed from the programme. Managers should also have basic competency levels in order to facilitate skill transfer through a mentorship process. The charge out rate of equipment should be revised every six months. The charge out rates should also be increased significantly to cater for the harsh conditions under which contractors are operational. A "champion" needs to be appointed which will actively seek exit opportunities for trained contractors. This person will also seek to develop functional partnerships with various private and government institutions to create opportunities for exited contractors.
- Full Text:
- Date Issued: 2005
- Authors: Knipe, Andrew
- Date: 2005
- Subjects: Working for Water Programme Contractors -- South Africa Construction contracts -- South Africa Business enterprises, Black -- South Africa Employee empowerment -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:799 , http://hdl.handle.net/10962/d1004916
- Description: This research is concerned with the development of independent contractors within the Working for Water Programme over a twenty-four month period. The meaningful participation of previously disadvantaged South Africans fall within the ambit of black economic empowerment. The Government Gazette (1997: No. 1820) defines black economic empowerment as a deliberate programme to achieve the meaningful participation of disadvantaged South Africans in the mainstream economy as managers, owners of capital and employees. The purpose of this research was to evaluate the contractors within the Western Region of the Eastern Cape, in order to assess how they have developed as independent contractors within the developmental framework provided by the Working for Water Programme. This developmental framework takes place over a 462-day period or roughly 24 months. The evaluation aimed to determine whether the two-year development period sufficiently prepared contractors for competition in the open market and if contractors had acquired the necessary skills to run a successful business. A formative programme evaluation was used as a tool of analysis to identify areas of weakness and establish priorities for improvement. A qualitative research approach was followed, guided by an adapted version of the Context, Input, Process and Product approach to evaluation (Parlett and Hamilton cited in Calder, 1995, p.25). Using structured interviews comprising of closed and open ended questions, data was gathered from thirty contractors, five managers and one Senior Executive Officer within the Western Region of the Eastern Cape. An interview was also conducted with the Regional Programme leader of the Eastern Cape. Further data collection techniques included documentary research. Data was analysed using qualitative data analysis techniques described by Thorne (1997, p.118), as relying on inductive reasoning to interpret and structure the meanings that can be derived from the data. Passages of interest were marked so that the data could be reduced to a manageable size as described by Seidman (1991, p.91-1 01) and various categories were developed that had commonalties and thematic connections. The Working for Water Programme aims to exit contractors successfully after a twenty-four month developmental period. The Working for Water Programme has formalised its development framework through a training matrix in which the required training at contractor level is outlined. The finding of the research is that the current contractor development programme do not adequately prepare contractors for independence and entrepreneurship in a competitive market. There is no co-ordinated development of predetermined skills. Contractors are not able to articulate what their plans are after exit from the WFW Programme. No concrete evidence of actively pursuing alternative contract opportunities was evident from contractors who were about to exit the Programme and there is no person to champion the cause of meaningful post exit opportunities. The main recommendations from this research are that contractors be selected via an application system rather that appointment through steering committees. Selected contractors must be medically fit and at least have a matriculation certificate. Contractors should be assessed on a 6-monthly basis and contractors not achieving a minimum competency level must be removed from the programme. Managers should also have basic competency levels in order to facilitate skill transfer through a mentorship process. The charge out rate of equipment should be revised every six months. The charge out rates should also be increased significantly to cater for the harsh conditions under which contractors are operational. A "champion" needs to be appointed which will actively seek exit opportunities for trained contractors. This person will also seek to develop functional partnerships with various private and government institutions to create opportunities for exited contractors.
- Full Text:
- Date Issued: 2005
Tanzaniops, replacement name for certain African Baetidae (Ephemeroptera)
- McCafferty, W P, Barber-James, Helen M
- Authors: McCafferty, W P , Barber-James, Helen M
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:7009 , http://hdl.handle.net/10962/d1008387
- Description: The name Tanzaniella, proposed for an African baetid mayfly by Gillies (1991) was preoccupied. The name Tanzaniops is provided as a replacement for this homonym.
- Full Text: false
- Date Issued: 2005
- Authors: McCafferty, W P , Barber-James, Helen M
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:7009 , http://hdl.handle.net/10962/d1008387
- Description: The name Tanzaniella, proposed for an African baetid mayfly by Gillies (1991) was preoccupied. The name Tanzaniops is provided as a replacement for this homonym.
- Full Text: false
- Date Issued: 2005
Synthesis, electrochemical and electrocatalytic behaviour of thiophene-appended cobalt, manganese and zinc phthalocyanine complexes
- Obirai, Joseph, Nyokong, Tebello
- Authors: Obirai, Joseph , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/286103 , vital:56238 , xlink:href="https://doi.org/10.1016/j.electacta.2005.03.024"
- Description: This work reports on the syntheses of new thiophene tetra substituted cobalt, manganese and zinc phthalocyanine (CoTETPc, (Cl)MnTETPc and ZnTETPc) complexes. The redox processes due to the thiophene substituent on the ring of the metallophthalocyanines (MPcs) were observed, in addition to Pc ring and metal (for Co and Mn complexes) based redox activity. The electrocatalytic activity of the CoTETPc complex adsorbed on glassy carbon electrode (GCE) by drop/dry-thermal annealing was investigated using L-cysteine. The modified electrode was stable to repetitive use without any signs of deactivation by oxidation products and was used to determine L-cysteine at concentrations between 0.0015 and 1 mM in pH 4 aqueous conditions.
- Full Text:
- Date Issued: 2005
- Authors: Obirai, Joseph , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/286103 , vital:56238 , xlink:href="https://doi.org/10.1016/j.electacta.2005.03.024"
- Description: This work reports on the syntheses of new thiophene tetra substituted cobalt, manganese and zinc phthalocyanine (CoTETPc, (Cl)MnTETPc and ZnTETPc) complexes. The redox processes due to the thiophene substituent on the ring of the metallophthalocyanines (MPcs) were observed, in addition to Pc ring and metal (for Co and Mn complexes) based redox activity. The electrocatalytic activity of the CoTETPc complex adsorbed on glassy carbon electrode (GCE) by drop/dry-thermal annealing was investigated using L-cysteine. The modified electrode was stable to repetitive use without any signs of deactivation by oxidation products and was used to determine L-cysteine at concentrations between 0.0015 and 1 mM in pH 4 aqueous conditions.
- Full Text:
- Date Issued: 2005
The symbiosis between capitalists:
- Authors: Kyazze, Simwogerere
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159211 , vital:40277 , https://hdl.handle.net/10520/EJC146362
- Description: Question: Who is the most famous writer of the New Millennium? Answer: JK Rowling, author of the Harry Potter stories. If you answered in the affirmative, you will be forgiven for sharing the view of many teenagers (and an increasing number of young adults) around the world who swear by Mr Potter's benign witchcraft. But while we ponder the Harry Potter juggernaut (Ms Rowling's books are bestsellers in any language), let us also ponder why very few serious intellectuals make it to the top of the world's most famous best-seller lists (The New York Times, Amazon.com, Times of London, etc). There is a reason why Gore Vidal, Jeffery Sachs, Noam Chomsky and Edward Said, have all had some of their best work published by little known outfits such as St Mark's Publishing House, and not celebrated imprints of the Simon and Schuster or Alfred Knopf calibre.
- Full Text:
- Date Issued: 2005
- Authors: Kyazze, Simwogerere
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159211 , vital:40277 , https://hdl.handle.net/10520/EJC146362
- Description: Question: Who is the most famous writer of the New Millennium? Answer: JK Rowling, author of the Harry Potter stories. If you answered in the affirmative, you will be forgiven for sharing the view of many teenagers (and an increasing number of young adults) around the world who swear by Mr Potter's benign witchcraft. But while we ponder the Harry Potter juggernaut (Ms Rowling's books are bestsellers in any language), let us also ponder why very few serious intellectuals make it to the top of the world's most famous best-seller lists (The New York Times, Amazon.com, Times of London, etc). There is a reason why Gore Vidal, Jeffery Sachs, Noam Chomsky and Edward Said, have all had some of their best work published by little known outfits such as St Mark's Publishing House, and not celebrated imprints of the Simon and Schuster or Alfred Knopf calibre.
- Full Text:
- Date Issued: 2005
Isolation, purification and characterization of inulin and fructooligosaccharides from chicorium intybus and inulinase from aspergillus niger
- Mavumengwana, Vuyo Bhongelethu
- Authors: Mavumengwana, Vuyo Bhongelethu
- Date: 2005
- Subjects: Aspergillus , Inulin , Chicory -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3954 , http://hdl.handle.net/10962/d1004013 , Aspergillus , Inulin , Chicory -- South Africa
- Description: Inulin is a non-digestible carbohydrate fructan polymer consisting mainly of β (1→2) fructosyl fructose links. Enzymatic hydrolysis of inulin by inulinase results in the production of low D.P (degree of polymerization) oligosaccharides also called fructooligosaccharides(FOS). Isolation of inulin from chicory root (Chicorium intybus) was achieved by first, extraction using deionized water (600C), followed by carbonation (0.1 M Ca(OH)2 and CO2 gas). This was filtered in order to remove the non sugars, thereafter, treated successfully with polyamide 6 powder. A cation exchanger and an anion exchanger were used to further exclude other components such as tannins and pigments. The extracted inulin was quantified using the Somogyi-Nelson colourimetric assay. Chicory root (207 g, 30 % being water) yielded 30 g of the raw extract. A 100 mg of the raw extract was assayed and found to contain 11 % yield of inulin which was 80.2 % in purity and 4 % free fructose. Analysis of the crude and purified inulin extracts on the MALDI TOF spectrometry showed the samples to have a DP of 2 to 22 and 2 to 27 respectively. Maximum inulinase production from Aspergillus niger grown on inulin was observed after 60 hours. The enzyme activity was found to be 1.168 U/ml with a temperature and pH optimum of 30 °C and 7.7 respectively. The enzyme proved to be unstable as it progressively lost its total activity during attempts at purification.
- Full Text:
- Date Issued: 2005
- Authors: Mavumengwana, Vuyo Bhongelethu
- Date: 2005
- Subjects: Aspergillus , Inulin , Chicory -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3954 , http://hdl.handle.net/10962/d1004013 , Aspergillus , Inulin , Chicory -- South Africa
- Description: Inulin is a non-digestible carbohydrate fructan polymer consisting mainly of β (1→2) fructosyl fructose links. Enzymatic hydrolysis of inulin by inulinase results in the production of low D.P (degree of polymerization) oligosaccharides also called fructooligosaccharides(FOS). Isolation of inulin from chicory root (Chicorium intybus) was achieved by first, extraction using deionized water (600C), followed by carbonation (0.1 M Ca(OH)2 and CO2 gas). This was filtered in order to remove the non sugars, thereafter, treated successfully with polyamide 6 powder. A cation exchanger and an anion exchanger were used to further exclude other components such as tannins and pigments. The extracted inulin was quantified using the Somogyi-Nelson colourimetric assay. Chicory root (207 g, 30 % being water) yielded 30 g of the raw extract. A 100 mg of the raw extract was assayed and found to contain 11 % yield of inulin which was 80.2 % in purity and 4 % free fructose. Analysis of the crude and purified inulin extracts on the MALDI TOF spectrometry showed the samples to have a DP of 2 to 22 and 2 to 27 respectively. Maximum inulinase production from Aspergillus niger grown on inulin was observed after 60 hours. The enzyme activity was found to be 1.168 U/ml with a temperature and pH optimum of 30 °C and 7.7 respectively. The enzyme proved to be unstable as it progressively lost its total activity during attempts at purification.
- Full Text:
- Date Issued: 2005
Stress, coping resources and adjustment of married mothers in the teaching profession
- Authors: Nell, Reinette Deidre
- Date: 2005
- Subjects: Women teachers -- Life skills assessment -- South Africa , Work and family -- South Africa -- Psychological aspects , Life skills , Stress (Psychology)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9851 , http://hdl.handle.net/10948/387 , Women teachers -- Life skills assessment -- South Africa , Work and family -- South Africa -- Psychological aspects , Life skills , Stress (Psychology)
- Description: The changes that have taken place in the South African educational system over the past few years have placed teachers under increasing stress. While abundant overseas literature is available regarding teacher stress, limited studies have focused specifically on South African samples. Female teachers, and working mothers, often experience additional stressors to men. Studies on women’s health have received little attention in comparison with the magnitude of research conducted on men’s health. The aim of the current study was to explore and describe the stress, coping resources and adjustment of married mothers in the teaching profession, and to explore and describe the patterns of stress and coping resources of these women. A non-experimental, exploratory descriptive study was employed. A biographical questionnaire and three paper-and-pencil measures, namely the Experience of Work and Life Questionnaire, the Coping Resources Inventory and the Personal, Home, Social and Formal Relations Questionnaire, were administered to 31 full-time primary school teachers who are married mothers of dependent children under the age of 14 years. A non-probability convenience sampling technique was employed. Descriptive statistics and cluster analysis were used in the data analysis. The results of the WLQ for this sample indicated that the mean score for the total level of stress fell within the high range, but with regards to the mode, the majority of the participants had average scores. The results of the CRI indicated an average level of coping resources for the present sample. The sample scored slightly above average on seven of the eleven components of the adjustment areas of the PHSF and slightly below average on the other four components. The participants in cluster one had average levels of stress and an average level of coping resources. The participants in cluster two scored very high levels of stress and average levels of coping resources. The participants in cluster three had very high levels of stress and low levels of coping resources. Suggestions were made for future research involving the stress, coping resources and adjustment of married mothers in the teaching profession. Finally, the limitations as well as the value of the research were outlined.
- Full Text:
- Date Issued: 2005
- Authors: Nell, Reinette Deidre
- Date: 2005
- Subjects: Women teachers -- Life skills assessment -- South Africa , Work and family -- South Africa -- Psychological aspects , Life skills , Stress (Psychology)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9851 , http://hdl.handle.net/10948/387 , Women teachers -- Life skills assessment -- South Africa , Work and family -- South Africa -- Psychological aspects , Life skills , Stress (Psychology)
- Description: The changes that have taken place in the South African educational system over the past few years have placed teachers under increasing stress. While abundant overseas literature is available regarding teacher stress, limited studies have focused specifically on South African samples. Female teachers, and working mothers, often experience additional stressors to men. Studies on women’s health have received little attention in comparison with the magnitude of research conducted on men’s health. The aim of the current study was to explore and describe the stress, coping resources and adjustment of married mothers in the teaching profession, and to explore and describe the patterns of stress and coping resources of these women. A non-experimental, exploratory descriptive study was employed. A biographical questionnaire and three paper-and-pencil measures, namely the Experience of Work and Life Questionnaire, the Coping Resources Inventory and the Personal, Home, Social and Formal Relations Questionnaire, were administered to 31 full-time primary school teachers who are married mothers of dependent children under the age of 14 years. A non-probability convenience sampling technique was employed. Descriptive statistics and cluster analysis were used in the data analysis. The results of the WLQ for this sample indicated that the mean score for the total level of stress fell within the high range, but with regards to the mode, the majority of the participants had average scores. The results of the CRI indicated an average level of coping resources for the present sample. The sample scored slightly above average on seven of the eleven components of the adjustment areas of the PHSF and slightly below average on the other four components. The participants in cluster one had average levels of stress and an average level of coping resources. The participants in cluster two scored very high levels of stress and average levels of coping resources. The participants in cluster three had very high levels of stress and low levels of coping resources. Suggestions were made for future research involving the stress, coping resources and adjustment of married mothers in the teaching profession. Finally, the limitations as well as the value of the research were outlined.
- Full Text:
- Date Issued: 2005
Effects of central metal on the photophysical and photochemical properties of non-transition metal sulfophthalocyanine
- Ogunsipe, Abimbola, Nyokong, Tebello
- Authors: Ogunsipe, Abimbola , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289337 , vital:56623 , xlink:href="https://doi.org/10.1142/S1088424605000186"
- Description: The photophysical and photochemical properties and quenching (by 1,4-benzoquinone) of metallophthalocyanine sulfonates of aluminium (AlPcSmix), zinc (ZnPcSmix), silicon (SiPcSmix), germanium (GePcSmix) and tin (SnPcSmix) are presented. The quantum yield values of fluorescence (ΦF), triplet state (ΦT), singlet oxygen (ΦΔ) and photodegradation (Φd) were determined and the observed trends in their variation among the complexes discussed in terms of aggregation and the heavy atom effect. 1,4-benzoquinone effectively quenched the fluorescence of the complexes. Quenching analyses gave positive deviations from Stern-Volmer behavior, suggesting the existence of static quenching in addition to dynamic quenching. The static and dynamic components of the quenching were separated using a modified Stern-Volmer equation and the “sphere of action quenching model”. The quenching constant was found to be a function of the radius of the central metal ion.
- Full Text:
- Date Issued: 2005
- Authors: Ogunsipe, Abimbola , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289337 , vital:56623 , xlink:href="https://doi.org/10.1142/S1088424605000186"
- Description: The photophysical and photochemical properties and quenching (by 1,4-benzoquinone) of metallophthalocyanine sulfonates of aluminium (AlPcSmix), zinc (ZnPcSmix), silicon (SiPcSmix), germanium (GePcSmix) and tin (SnPcSmix) are presented. The quantum yield values of fluorescence (ΦF), triplet state (ΦT), singlet oxygen (ΦΔ) and photodegradation (Φd) were determined and the observed trends in their variation among the complexes discussed in terms of aggregation and the heavy atom effect. 1,4-benzoquinone effectively quenched the fluorescence of the complexes. Quenching analyses gave positive deviations from Stern-Volmer behavior, suggesting the existence of static quenching in addition to dynamic quenching. The static and dynamic components of the quenching were separated using a modified Stern-Volmer equation and the “sphere of action quenching model”. The quenching constant was found to be a function of the radius of the central metal ion.
- Full Text:
- Date Issued: 2005
Conceptualizing and implementing the meaning of Africa's new partnership with the industrialized north : implications and possibilities for the renaissance
- Authors: Somhlaba, Zamokwakhe Ludidi
- Date: 2005
- Subjects: New Partnership for Africa's Development , Sustainable development -- Africa , Economic development -- Africa , Africa -- Foreign economic relations , Africa -- Economic conditions -- 1960-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2841 , http://hdl.handle.net/10962/d1004655 , New Partnership for Africa's Development , Sustainable development -- Africa , Economic development -- Africa , Africa -- Foreign economic relations , Africa -- Economic conditions -- 1960-
- Description: This study is a contribution to the on-going debate about the path that Africa has taken in realising the vision of its renewal. The central theme of the study is the idea of Africa's 'new partnership' with the industrialised North, which is envisaged under the New Partnership for Africa's Development (NEPAD). Acknowledging that asymmetrical partnerships have existed between Africa and the North, particularly in the last century, the question this study poses is: to what extent does the idea of the 'new partnership' represent something new? The study argues two points. Firstly, it argues that the idea of the new partnership has become a terrain of contestation between the Africanist and the post-modernist social forces. Secondly, the study argues that it is unlikely that conceptualising the idea of the new partnership in post-modernist terms will result in sustainable development and rebirth of Africa. That is particularly the case, because post-modernity suggests a certain degree of loyalty to the prevailing and asymmetrical global order. Against this background, the study concludes that the extent to which Africa will enjoy the benefits of a truly revised partnership with the North, and thus fulfil the vision of its rebirth, will be determined, by and large, by the modalities of accommodation and struggle between these social forces.
- Full Text:
- Date Issued: 2005
- Authors: Somhlaba, Zamokwakhe Ludidi
- Date: 2005
- Subjects: New Partnership for Africa's Development , Sustainable development -- Africa , Economic development -- Africa , Africa -- Foreign economic relations , Africa -- Economic conditions -- 1960-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2841 , http://hdl.handle.net/10962/d1004655 , New Partnership for Africa's Development , Sustainable development -- Africa , Economic development -- Africa , Africa -- Foreign economic relations , Africa -- Economic conditions -- 1960-
- Description: This study is a contribution to the on-going debate about the path that Africa has taken in realising the vision of its renewal. The central theme of the study is the idea of Africa's 'new partnership' with the industrialised North, which is envisaged under the New Partnership for Africa's Development (NEPAD). Acknowledging that asymmetrical partnerships have existed between Africa and the North, particularly in the last century, the question this study poses is: to what extent does the idea of the 'new partnership' represent something new? The study argues two points. Firstly, it argues that the idea of the new partnership has become a terrain of contestation between the Africanist and the post-modernist social forces. Secondly, the study argues that it is unlikely that conceptualising the idea of the new partnership in post-modernist terms will result in sustainable development and rebirth of Africa. That is particularly the case, because post-modernity suggests a certain degree of loyalty to the prevailing and asymmetrical global order. Against this background, the study concludes that the extent to which Africa will enjoy the benefits of a truly revised partnership with the North, and thus fulfil the vision of its rebirth, will be determined, by and large, by the modalities of accommodation and struggle between these social forces.
- Full Text:
- Date Issued: 2005
Investigation of the effect of selected polypropylene fibres and ultra-fine aggregate on plastic shrinkage cracks on South African roads
- Authors: Kluyts, Grant
- Date: 2005
- Subjects: Concrete roads -- South Africa -- Design and construction , Fiber-reinforced concrete , Reinforced concrete -- Cracking , Concrete -- Expansion and contraction , Polypropylene fibers
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9592 , http://hdl.handle.net/10948/174 , Concrete roads -- South Africa -- Design and construction , Fiber-reinforced concrete , Reinforced concrete -- Cracking , Concrete -- Expansion and contraction , Polypropylene fibers
- Description: Plastic shrinkage cracks, although not inherently structurally debilitating, expose the reinforcement in low-volume reinforced concrete roads to deleterious substances, which may reduce its effectiveness leading ultimately to structural failure. In un-reinforced low-volume concrete road these cracks appear unsightly and cause the road user an unpleasant riding experience. Many researchers believe that plastic shrinkage crack development remains a concern to the concrete industry, occurring in particularly large–area pours such as low-volume concrete roads, and therefore requires further research to understand their formation and minimization. This study reports findings on the effectiveness of oxyfluorinated polypropylene fibres to control plastic shrinkage cracks, and the effect the addition of ultra-fine material has on the formation and/or propagation of these cracks. Findings indicate that low volume dosages (2 kg/m³), of oxyfluorinated polypropylene fibre significantly reduced the formation of plastic shrinkage cracks under test conditions. Furthermore, that the addition of ultra-fine material in excess of 63 kg/m³ increased the formation and/or development of plastic shrinkage cracks.
- Full Text:
- Date Issued: 2005
- Authors: Kluyts, Grant
- Date: 2005
- Subjects: Concrete roads -- South Africa -- Design and construction , Fiber-reinforced concrete , Reinforced concrete -- Cracking , Concrete -- Expansion and contraction , Polypropylene fibers
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9592 , http://hdl.handle.net/10948/174 , Concrete roads -- South Africa -- Design and construction , Fiber-reinforced concrete , Reinforced concrete -- Cracking , Concrete -- Expansion and contraction , Polypropylene fibers
- Description: Plastic shrinkage cracks, although not inherently structurally debilitating, expose the reinforcement in low-volume reinforced concrete roads to deleterious substances, which may reduce its effectiveness leading ultimately to structural failure. In un-reinforced low-volume concrete road these cracks appear unsightly and cause the road user an unpleasant riding experience. Many researchers believe that plastic shrinkage crack development remains a concern to the concrete industry, occurring in particularly large–area pours such as low-volume concrete roads, and therefore requires further research to understand their formation and minimization. This study reports findings on the effectiveness of oxyfluorinated polypropylene fibres to control plastic shrinkage cracks, and the effect the addition of ultra-fine material has on the formation and/or propagation of these cracks. Findings indicate that low volume dosages (2 kg/m³), of oxyfluorinated polypropylene fibre significantly reduced the formation of plastic shrinkage cracks under test conditions. Furthermore, that the addition of ultra-fine material in excess of 63 kg/m³ increased the formation and/or development of plastic shrinkage cracks.
- Full Text:
- Date Issued: 2005
A re-evaluation of plastochron index determination in peas - a case for using leaflet length
- Ade-Ademilua, Omobolanle Elizabeth, Botha, Christiaan E J
- Authors: Ade-Ademilua, Omobolanle Elizabeth , Botha, Christiaan E J
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6491 , http://hdl.handle.net/10962/d1004472
- Description: The plastochron index (PI) is a measure of plant growth reports our findings on PI using the average length of and can be used to determine growth rate, based upon the first pair of leaflets on each node. Early leaflet appearance of successive leaves on the axis of the growth in peas occurs exponentially and the early plant. PI should under ideal growth conditions be a stages of growth of successive pairs of leaflets occur at regular event and should be predictable with a relatively the same relative growth rate. Given that growth of small error of a few hours. PI has been variously leaflets during early development can be measured calculated in peas, and each method reported has had successfully, we propose the use of leaflet growth as a with it a number of problems that do not allow for measure of the plastochron index in peas. Our results reasonable prediction of PI. Internode length varies suggest that plant age is best expressed using the greatly and is dependent upon the variety, which may be plastochron index, which is a measure of the time short- or long-stemmed; thus this parameter is not ideal interval between the initiations of successive events — for determining growth rate or plant age. This paper in the case of peas, of successive pairs of leaflets.
- Full Text:
- Date Issued: 2005
- Authors: Ade-Ademilua, Omobolanle Elizabeth , Botha, Christiaan E J
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6491 , http://hdl.handle.net/10962/d1004472
- Description: The plastochron index (PI) is a measure of plant growth reports our findings on PI using the average length of and can be used to determine growth rate, based upon the first pair of leaflets on each node. Early leaflet appearance of successive leaves on the axis of the growth in peas occurs exponentially and the early plant. PI should under ideal growth conditions be a stages of growth of successive pairs of leaflets occur at regular event and should be predictable with a relatively the same relative growth rate. Given that growth of small error of a few hours. PI has been variously leaflets during early development can be measured calculated in peas, and each method reported has had successfully, we propose the use of leaflet growth as a with it a number of problems that do not allow for measure of the plastochron index in peas. Our results reasonable prediction of PI. Internode length varies suggest that plant age is best expressed using the greatly and is dependent upon the variety, which may be plastochron index, which is a measure of the time short- or long-stemmed; thus this parameter is not ideal interval between the initiations of successive events — for determining growth rate or plant age. This paper in the case of peas, of successive pairs of leaflets.
- Full Text:
- Date Issued: 2005
Contending issues in South Africa's foreign policy : universalism versus economic national interest : the case of South Africa's arms sales to 'pariah states' 1994-1999
- Authors: Othieno, Timothy
- Date: 2005
- Subjects: South Africa -- Foreign relations -- 1994- South Africa -- Politics and government -- 1994- South Africa -- Foreign economic relations Arms transfers -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2868 , http://hdl.handle.net/10962/d1007712
- Description: This study examines post-apartheid South African foreign policy under former President Nelson Mandela, and the apparent ambiguities that were its recurrent feature in the period from 1994 to 1999. Its focus is on the inherent irreconcilability of the economic national interests and the foreign policy principles which included the promotion of and respect for universalist principles and interests such as human rights, democracy, international peace and security. In examining South African foreign policy during this period, it would appear that the country was trapped between two competing priorities: the need to promote "universalist" principles and the need to satisfy its national economic interests. The main aim of the study is to explain how this "irreconcilability" between universalist principles and national economic interests would later create ambiguities and contradictions in South Africa's foreign policy, weaken respect for its foreign policy principles, and ultimately lead to ideological failure among politicians who employed 'short-term gain' policy decision-making in dealing with 'pariah states'. The study further demonstrates that "realist" national interests are frequently short-term, realizable and vital for a country, while universalist interests are long-term, idealistic and usually not easily realizable. It will be argued, therefore, that a country faced with making decisions about its vital national interests, will not make efforts to pursue long-term universalist interests if that choice would in any way endanger its fundamental national interests. In order to better assess this ambiguity, this thesis will provide a case study of Pretoria's arms sales to 'pariah states' during the period. The purpose of this study is not to attempt to explain all of the issues around post-apartheid foreign policymaking, or even to argue whether the sale of arms to 'pariah states' was 'politically incorrect', but to provide a 'piece of the puzzle' which might explain how the social and economic situation may have compelled Pretoria to sell arms when these actions disregarded universalist principles of foreign policy. The conclusion seems to confirm the realist view that universal values and principles can be regarded only when they are in harmony with a state's perceived self-interests.
- Full Text:
- Date Issued: 2005
- Authors: Othieno, Timothy
- Date: 2005
- Subjects: South Africa -- Foreign relations -- 1994- South Africa -- Politics and government -- 1994- South Africa -- Foreign economic relations Arms transfers -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2868 , http://hdl.handle.net/10962/d1007712
- Description: This study examines post-apartheid South African foreign policy under former President Nelson Mandela, and the apparent ambiguities that were its recurrent feature in the period from 1994 to 1999. Its focus is on the inherent irreconcilability of the economic national interests and the foreign policy principles which included the promotion of and respect for universalist principles and interests such as human rights, democracy, international peace and security. In examining South African foreign policy during this period, it would appear that the country was trapped between two competing priorities: the need to promote "universalist" principles and the need to satisfy its national economic interests. The main aim of the study is to explain how this "irreconcilability" between universalist principles and national economic interests would later create ambiguities and contradictions in South Africa's foreign policy, weaken respect for its foreign policy principles, and ultimately lead to ideological failure among politicians who employed 'short-term gain' policy decision-making in dealing with 'pariah states'. The study further demonstrates that "realist" national interests are frequently short-term, realizable and vital for a country, while universalist interests are long-term, idealistic and usually not easily realizable. It will be argued, therefore, that a country faced with making decisions about its vital national interests, will not make efforts to pursue long-term universalist interests if that choice would in any way endanger its fundamental national interests. In order to better assess this ambiguity, this thesis will provide a case study of Pretoria's arms sales to 'pariah states' during the period. The purpose of this study is not to attempt to explain all of the issues around post-apartheid foreign policymaking, or even to argue whether the sale of arms to 'pariah states' was 'politically incorrect', but to provide a 'piece of the puzzle' which might explain how the social and economic situation may have compelled Pretoria to sell arms when these actions disregarded universalist principles of foreign policy. The conclusion seems to confirm the realist view that universal values and principles can be regarded only when they are in harmony with a state's perceived self-interests.
- Full Text:
- Date Issued: 2005
Impacts of wildlife and cattle grazing on spider (araneae) biodiversity in a highland savanna ecosystem, in Laikipia, Central Kenya
- Authors: Warui, Charles Mwaura
- Date: 2005
- Subjects: Spiders -- Kenya Environmental monitoring -- Kenya Savanna ecology -- Kenya Biodiversity -- Kenya Species diversity -- Kenya Wildlife management -- Kenya Herbivores -- Ecology -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5712 , http://hdl.handle.net/10962/d1005398
- Description: Spiders were sampled at Mpala Research Centre, Laikipia, Kenya by pitfall-trapping and sweep-netting from May 2001 to July 2002, at a Kenyan Long-term Exclosure Experiment. The aim was to establish species composition, checklist and examine spider responses to disturbances caused by cattle, megaherbivores (giraffe and elephants) and mesoherbivores (other ungulates) by looking at three levels of resolution, namely the overall community, guilds and individual species. This is the first controlled replicated experimental study on the effects on invertebrates (spiders) by different land uses (access by large herbivores). A total of 10,487 individuals from 132 species belonging to 30 families were recorded. The family Salticidae had the highest number of species (24), followed by Gnaphosidae (20), Araneidae and Lycosidae (15 each), Theridiidae and Thomisidae (8 each) and Zodariidae (4). Most of the other families had fewer than 4 species. Throughout the study period, species not previously sampled emerged after rainfall peaks. Exclosure treatments affected plant cover, spider diversity and total species mainly through the effects of cattle, whose presence significantly reduced relative vegetation cover. An increase in vegetation cover significantly increased the diversity, total species and species evenness of the overall spider community (total samples data set). Megaherbivores and mesoherbivores had no effects on overall spider diversity. Relative vegetation cover explained approximately 20-30% of variation in community diversity, species richness and species evenness. At the guild level of resolution, the exclosure treatments had no significant effects on diversity, species richness and species evenness of web builders, plant wanderers and ground wanderers. Plant wanderers were significantly and positively correlated with relative vegetation cover, which explained 17% of variation in their diversity. Six individual species responded strongly and in contrasting ways to the same environmental variables, indicating that this level was more sensitive to environmental changes than guilds or the overall spider community. Spider diversity, relative vegetation cover and rainfall varied at a temporal scale of months and not at a spatial scale of hundreds of metres. Only species diversity and species richness from sweep-netting samples and total species from pitfall-trapping varied significantly at a spatial scale of hundreds of metres. Ordination analysis revealed that sweep-netting samples were a better indicator of grazing impacts than pitfalltrapping or combined samples and grouped to reflect cattle grazing, non-cattle grazing and to a small extent the control treatments. Other ordination analyses showed that only samples from sweep-netting and not from pitfall-trapping, were spatially partitioned at a scale of hundreds of metres. This study concludes that the spider fauna of black cotton soil habitats is rich and useful for environmental monitoring and that monitoring of several individual species as indicator of grazing impacts in savanna could be useful and relatively easy.
- Full Text:
- Date Issued: 2005
- Authors: Warui, Charles Mwaura
- Date: 2005
- Subjects: Spiders -- Kenya Environmental monitoring -- Kenya Savanna ecology -- Kenya Biodiversity -- Kenya Species diversity -- Kenya Wildlife management -- Kenya Herbivores -- Ecology -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5712 , http://hdl.handle.net/10962/d1005398
- Description: Spiders were sampled at Mpala Research Centre, Laikipia, Kenya by pitfall-trapping and sweep-netting from May 2001 to July 2002, at a Kenyan Long-term Exclosure Experiment. The aim was to establish species composition, checklist and examine spider responses to disturbances caused by cattle, megaherbivores (giraffe and elephants) and mesoherbivores (other ungulates) by looking at three levels of resolution, namely the overall community, guilds and individual species. This is the first controlled replicated experimental study on the effects on invertebrates (spiders) by different land uses (access by large herbivores). A total of 10,487 individuals from 132 species belonging to 30 families were recorded. The family Salticidae had the highest number of species (24), followed by Gnaphosidae (20), Araneidae and Lycosidae (15 each), Theridiidae and Thomisidae (8 each) and Zodariidae (4). Most of the other families had fewer than 4 species. Throughout the study period, species not previously sampled emerged after rainfall peaks. Exclosure treatments affected plant cover, spider diversity and total species mainly through the effects of cattle, whose presence significantly reduced relative vegetation cover. An increase in vegetation cover significantly increased the diversity, total species and species evenness of the overall spider community (total samples data set). Megaherbivores and mesoherbivores had no effects on overall spider diversity. Relative vegetation cover explained approximately 20-30% of variation in community diversity, species richness and species evenness. At the guild level of resolution, the exclosure treatments had no significant effects on diversity, species richness and species evenness of web builders, plant wanderers and ground wanderers. Plant wanderers were significantly and positively correlated with relative vegetation cover, which explained 17% of variation in their diversity. Six individual species responded strongly and in contrasting ways to the same environmental variables, indicating that this level was more sensitive to environmental changes than guilds or the overall spider community. Spider diversity, relative vegetation cover and rainfall varied at a temporal scale of months and not at a spatial scale of hundreds of metres. Only species diversity and species richness from sweep-netting samples and total species from pitfall-trapping varied significantly at a spatial scale of hundreds of metres. Ordination analysis revealed that sweep-netting samples were a better indicator of grazing impacts than pitfalltrapping or combined samples and grouped to reflect cattle grazing, non-cattle grazing and to a small extent the control treatments. Other ordination analyses showed that only samples from sweep-netting and not from pitfall-trapping, were spatially partitioned at a scale of hundreds of metres. This study concludes that the spider fauna of black cotton soil habitats is rich and useful for environmental monitoring and that monitoring of several individual species as indicator of grazing impacts in savanna could be useful and relatively easy.
- Full Text:
- Date Issued: 2005
The effect of new teaching methods in chemistry on the foundation certificate learners' results
- Authors: Nagel, Lilian Estelle
- Date: 2005
- Subjects: Chemistry -- Study and teaching (Higher)
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10787 , http://hdl.handle.net/10948/162 , Chemistry -- Study and teaching (Higher)
- Description: This study investigated possible alternative Chemistry teaching methods to improve the learning and thus the pass rate of the learners of access programmes at the Port Elizabeth Technikon. The study traced Chemistry learning from the Pre-Technician course to the present Science Foundation Certificate. Since the latter programme is a new course with new criteria, only implemented since the beginning of 2003, it provided a suitable platform for the evaluation and updating, if necessary, of new teaching methods. The study was limited to the subject of Chemistry. The participating learners in this qualitative research were fully informed of the objectives of this research and, for ethical reasons, their identities were protected. The methodology chosen was action research, which will include discussions regarding the choice, necessity and value of the research method. The following tools were used to collect data to determine approaches to learning and how the examination results were influenced: Questionnaires; Journal entries of students; Interviews; Data of examination results.
- Full Text:
- Date Issued: 2005
- Authors: Nagel, Lilian Estelle
- Date: 2005
- Subjects: Chemistry -- Study and teaching (Higher)
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10787 , http://hdl.handle.net/10948/162 , Chemistry -- Study and teaching (Higher)
- Description: This study investigated possible alternative Chemistry teaching methods to improve the learning and thus the pass rate of the learners of access programmes at the Port Elizabeth Technikon. The study traced Chemistry learning from the Pre-Technician course to the present Science Foundation Certificate. Since the latter programme is a new course with new criteria, only implemented since the beginning of 2003, it provided a suitable platform for the evaluation and updating, if necessary, of new teaching methods. The study was limited to the subject of Chemistry. The participating learners in this qualitative research were fully informed of the objectives of this research and, for ethical reasons, their identities were protected. The methodology chosen was action research, which will include discussions regarding the choice, necessity and value of the research method. The following tools were used to collect data to determine approaches to learning and how the examination results were influenced: Questionnaires; Journal entries of students; Interviews; Data of examination results.
- Full Text:
- Date Issued: 2005
Puerulus and early juvenile recruitment of the rock lobster jasus lalandii in relation to the environment at Lüderitz Bay, Namibia
- Authors: Keulder, Felicia Juanita
- Date: 2005
- Subjects: Jasus lalandii , Lobster fisheries -- Namibia , Lobster culture -- Namibia
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5315 , http://hdl.handle.net/10962/d1005160 , Jasus lalandii , Lobster fisheries -- Namibia , Lobster culture -- Namibia
- Description: A global decline in the lobster fishery has necessitated the growout of wild-caught postlarvae (pueruli) on farms to meet the worlds lobster demand. A limited knowledge on puerulus settlement in the West Coast rock lobster (Jasus lalandii) constitutes a major barrier for J. lalandii culture development in Southern Africa. As an extension of an existing long-term puerulus monitoring program of the Ministry of Fisheries and Marine Resources of Namibia, the present study monitored puerulus recruitment (supply), puerulus condition and juvenile growth of J. lalandii and their relationship with environmental variables on an oyster farm at Lüderitz Bay, Namibia. Implications for lobster aquaculture and fisheries management are discussed. Oyster bags, crates and collectors were sampled daily, weekly and bimonthly, for pueruli and juveniles, respectively, between August 2001 and July 2003 to establish spatialtemporal patterns in their distribution. Animals were transported to the laboratory for morphometric analyses where they were staged as puerulus (Pt = transparent; Pp = pigmented) and juvenile lobsters. The carapace lengths (0.1mm CL) and wet weights (0.01gram) of animals were recorded. Carapace length frequencies were subjected to Modal Progression analysis to identify early juvenile cohorts and calculate their growths. The weight-length ratios calculated and percentage fat content were used as indices of nutritional condition. Seasonal peaks in puerulus and juvenile abundance were estimated using Periodic Regression analysis. The relationships of puerulus and juvenile abundance with respect to sea surface temperature (SST), wind speed-direction, moon phase, swell and tidal range were established using time lag analysis (ADL). Transparent pueruli were randomly distributed on oyster bags and crates, and also between collector sites, suggesting that they have no particular settlement preference for certain areas on these structures (p>0.05; n=150). Pigmented puerulus (p<0.05; n=566) and juveniles (p<0.05; n=3528) preferred structurally complex structures that provided better shelter such as crates, which were more sheltered from sea swells, compared to oyster bags. Among oyster rafts, pigmented puerulus and juveniles preferred occupying the sheltered and centred raft areas, which provided better protection from wave action, compared to exposed raft areas, which were exposed to the incoming swell. Puerulus and juvenile lobster appeared to recolonise adjacent bags and crates, and possibly migrate to the substrate and off the farm due to the disturbance of the habitat during harvesting. The booth crevice collector was more efficient in collecting puerulus possibly due to the high structurally complex habitat and the better shelter they provided compared to the hogshair collector. The occupation of structurally complex habitats by early benthic stages may be related to morphological changes associated with metamorphosis. Puerulus settlement peaked during early spring (August-September) and was related to low sea surface temperatures (12.3°C), strong south winds, and moderate swells in the week preceding settlement. These conditions are synonymous with the “spring upwelling” season of the Lüderitz upwelling cell in the central Benguela current region. Puerulus nutritional condition peaked during this period possibly due to high levels of planktonic food (due to high nutrients from upwelling) that was available to the late stage phyllosoma larvae further offshore. A “good” puerulus settlement year during 2000 was associated with lower than average SST (11.6°C) and strong south winds and was followed by “poor” puerulus settlement years during 2001 and 2002 when higher than average SST were experienced with below average wind speeds experienced during 2001 only. Puerulus of J. lalandii recruited in high numbers into Lüderitz Bay during the new moon, full moon and last quarter moon phases by making use of the increased tides during these phases of the lunar cycle. Peak juvenile abundance during early summer (November-December) lagged by 8 weeks was significantly correlated with peak puerulus abundance. Puerulus size was similar (8.5–9.7mm CL) over the study period. Juvenile cohorts, 9.9-20.6mm CL in size recruited in 2 distinct waves in August 2001-June 2002 and July 2002-February 2003. The 2001/2002 recruits had higher monthly growth increments and better nutritional condition compared to 2002/2003 recruits. Peak frequencies of 2nd moult juveniles (9.9- 10.8mm CL) occurred in September of both recruitment events with nutritional condition being poorest during the 2002/2003 event. The nutritional condition of the settling puerulus did not appear to be related to the subsequent growth of juvenile lobster. These preliminary results suggest that pueruli recruit once a year mainly during late winter/ early spring under conditions typical of coastal upwelling in the Benguela current near Lüderitz. It appears that puerulus settlement is driven by favourable shoreward currents, which help in transporting puerulus to their settlement grounds. Puerulus supply is highly variable between years, which appears to be consistent with a highly variable Benguela environment. The oyster farm supported a substantial standing stock averaging 123 800 lobster per day (range: 22 600-325 300 lobster per day) of which 26 600 were puerulus and 97 200 were juveniles, that may have been harvested once off on any given day during the sample period. Monthly harvesting of the total lobster standing stock during the one and a half year sampling period was just over 2 million lobsters (505 700 pueruli and 1.85 million juveniles) and would potentially have been sufficient seed for a 200 ton lobster production in puerulus lobster growout facilities. In the light of high inter-annual variation in puerulus settlement observed at Lüderitz, the seed supply at the Lüderitz oyster farm is clearly limited and therefore it is prudent that other sites of high puerulus settlement is established before large commercial scale lobster growout can commence. The migration of lobster off the farm suggested that these lobsters potentially recruit to the fishery and therefore harvesting the entire standing stock on the farm may have adverse negative effects on the wild fishery. A policy decision will be required as to whether more efficient harvesting of lobster from the farm should be allowed. If puerulus removal in J. lalandii for aquaculture is allowed in the near future, it should be conducted on an experimental scale or small commercial scale until the potential effects on recruitment into the fishery are clearer.
- Full Text:
- Date Issued: 2005
- Authors: Keulder, Felicia Juanita
- Date: 2005
- Subjects: Jasus lalandii , Lobster fisheries -- Namibia , Lobster culture -- Namibia
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5315 , http://hdl.handle.net/10962/d1005160 , Jasus lalandii , Lobster fisheries -- Namibia , Lobster culture -- Namibia
- Description: A global decline in the lobster fishery has necessitated the growout of wild-caught postlarvae (pueruli) on farms to meet the worlds lobster demand. A limited knowledge on puerulus settlement in the West Coast rock lobster (Jasus lalandii) constitutes a major barrier for J. lalandii culture development in Southern Africa. As an extension of an existing long-term puerulus monitoring program of the Ministry of Fisheries and Marine Resources of Namibia, the present study monitored puerulus recruitment (supply), puerulus condition and juvenile growth of J. lalandii and their relationship with environmental variables on an oyster farm at Lüderitz Bay, Namibia. Implications for lobster aquaculture and fisheries management are discussed. Oyster bags, crates and collectors were sampled daily, weekly and bimonthly, for pueruli and juveniles, respectively, between August 2001 and July 2003 to establish spatialtemporal patterns in their distribution. Animals were transported to the laboratory for morphometric analyses where they were staged as puerulus (Pt = transparent; Pp = pigmented) and juvenile lobsters. The carapace lengths (0.1mm CL) and wet weights (0.01gram) of animals were recorded. Carapace length frequencies were subjected to Modal Progression analysis to identify early juvenile cohorts and calculate their growths. The weight-length ratios calculated and percentage fat content were used as indices of nutritional condition. Seasonal peaks in puerulus and juvenile abundance were estimated using Periodic Regression analysis. The relationships of puerulus and juvenile abundance with respect to sea surface temperature (SST), wind speed-direction, moon phase, swell and tidal range were established using time lag analysis (ADL). Transparent pueruli were randomly distributed on oyster bags and crates, and also between collector sites, suggesting that they have no particular settlement preference for certain areas on these structures (p>0.05; n=150). Pigmented puerulus (p<0.05; n=566) and juveniles (p<0.05; n=3528) preferred structurally complex structures that provided better shelter such as crates, which were more sheltered from sea swells, compared to oyster bags. Among oyster rafts, pigmented puerulus and juveniles preferred occupying the sheltered and centred raft areas, which provided better protection from wave action, compared to exposed raft areas, which were exposed to the incoming swell. Puerulus and juvenile lobster appeared to recolonise adjacent bags and crates, and possibly migrate to the substrate and off the farm due to the disturbance of the habitat during harvesting. The booth crevice collector was more efficient in collecting puerulus possibly due to the high structurally complex habitat and the better shelter they provided compared to the hogshair collector. The occupation of structurally complex habitats by early benthic stages may be related to morphological changes associated with metamorphosis. Puerulus settlement peaked during early spring (August-September) and was related to low sea surface temperatures (12.3°C), strong south winds, and moderate swells in the week preceding settlement. These conditions are synonymous with the “spring upwelling” season of the Lüderitz upwelling cell in the central Benguela current region. Puerulus nutritional condition peaked during this period possibly due to high levels of planktonic food (due to high nutrients from upwelling) that was available to the late stage phyllosoma larvae further offshore. A “good” puerulus settlement year during 2000 was associated with lower than average SST (11.6°C) and strong south winds and was followed by “poor” puerulus settlement years during 2001 and 2002 when higher than average SST were experienced with below average wind speeds experienced during 2001 only. Puerulus of J. lalandii recruited in high numbers into Lüderitz Bay during the new moon, full moon and last quarter moon phases by making use of the increased tides during these phases of the lunar cycle. Peak juvenile abundance during early summer (November-December) lagged by 8 weeks was significantly correlated with peak puerulus abundance. Puerulus size was similar (8.5–9.7mm CL) over the study period. Juvenile cohorts, 9.9-20.6mm CL in size recruited in 2 distinct waves in August 2001-June 2002 and July 2002-February 2003. The 2001/2002 recruits had higher monthly growth increments and better nutritional condition compared to 2002/2003 recruits. Peak frequencies of 2nd moult juveniles (9.9- 10.8mm CL) occurred in September of both recruitment events with nutritional condition being poorest during the 2002/2003 event. The nutritional condition of the settling puerulus did not appear to be related to the subsequent growth of juvenile lobster. These preliminary results suggest that pueruli recruit once a year mainly during late winter/ early spring under conditions typical of coastal upwelling in the Benguela current near Lüderitz. It appears that puerulus settlement is driven by favourable shoreward currents, which help in transporting puerulus to their settlement grounds. Puerulus supply is highly variable between years, which appears to be consistent with a highly variable Benguela environment. The oyster farm supported a substantial standing stock averaging 123 800 lobster per day (range: 22 600-325 300 lobster per day) of which 26 600 were puerulus and 97 200 were juveniles, that may have been harvested once off on any given day during the sample period. Monthly harvesting of the total lobster standing stock during the one and a half year sampling period was just over 2 million lobsters (505 700 pueruli and 1.85 million juveniles) and would potentially have been sufficient seed for a 200 ton lobster production in puerulus lobster growout facilities. In the light of high inter-annual variation in puerulus settlement observed at Lüderitz, the seed supply at the Lüderitz oyster farm is clearly limited and therefore it is prudent that other sites of high puerulus settlement is established before large commercial scale lobster growout can commence. The migration of lobster off the farm suggested that these lobsters potentially recruit to the fishery and therefore harvesting the entire standing stock on the farm may have adverse negative effects on the wild fishery. A policy decision will be required as to whether more efficient harvesting of lobster from the farm should be allowed. If puerulus removal in J. lalandii for aquaculture is allowed in the near future, it should be conducted on an experimental scale or small commercial scale until the potential effects on recruitment into the fishery are clearer.
- Full Text:
- Date Issued: 2005
Modeling and measurement of torqued procession in radio pulsars
- Authors: Tiplady, Adrian John
- Date: 2005
- Subjects: Pulsars , Radio telescopes , Radio astronomy , Precession , Hartebeeshoek Radio Astronomy Observatory (HartRAO)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5475 , http://hdl.handle.net/10962/d1005260
- Description: The long term isolated pulsar monitoring program, which commenced in 1984 using the 26 m radio telescope at the Hartebeeshoek Radio Astronomy Observatory (HartRAO), has produced high resolution timing residual data over long timespans. This has enabled the analysis of observed spin down behaviour for 27 braking pulsars, most of which have dataspans longer than 14 years. The phenomenology of observed timing residuals of certain pulsars can be explained by pseudo periodic effects such as precession. Analytic and numerical models are developed to study the kinematic and dynamic behaviour of isolated but torqued precessing pulsars. The predicted timing residual behaviour of the models is characterised, and confronted with timing data from selected pulsars. Cyclic variations in the observed timing residuals of PSR B1642-03, PSR B1323-58 and PSR B1557-50 are fitted with a torqued precession model. The phenomenology of the observed timing behaviour of these pulsars can be explained by the precession models, but precise model fitting was not possible. This is not surprising given that the complexity of the pulsar systems is not completely described by the model. The extension of the pulsar monitoring program at HartRAO is used as motivation for the design and development of a new low cost, multi-purpose digital pulsar receiver. The instrument is implemented using a hybrid filterbank architecture, consisting of an analogue frontend and digital backend, to perform incoherent dedispersion. The design of a polyphase filtering system, which will consolidate multiple processing units into a single filtering solution, is discussed for future implementation.
- Full Text:
- Date Issued: 2005
- Authors: Tiplady, Adrian John
- Date: 2005
- Subjects: Pulsars , Radio telescopes , Radio astronomy , Precession , Hartebeeshoek Radio Astronomy Observatory (HartRAO)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5475 , http://hdl.handle.net/10962/d1005260
- Description: The long term isolated pulsar monitoring program, which commenced in 1984 using the 26 m radio telescope at the Hartebeeshoek Radio Astronomy Observatory (HartRAO), has produced high resolution timing residual data over long timespans. This has enabled the analysis of observed spin down behaviour for 27 braking pulsars, most of which have dataspans longer than 14 years. The phenomenology of observed timing residuals of certain pulsars can be explained by pseudo periodic effects such as precession. Analytic and numerical models are developed to study the kinematic and dynamic behaviour of isolated but torqued precessing pulsars. The predicted timing residual behaviour of the models is characterised, and confronted with timing data from selected pulsars. Cyclic variations in the observed timing residuals of PSR B1642-03, PSR B1323-58 and PSR B1557-50 are fitted with a torqued precession model. The phenomenology of the observed timing behaviour of these pulsars can be explained by the precession models, but precise model fitting was not possible. This is not surprising given that the complexity of the pulsar systems is not completely described by the model. The extension of the pulsar monitoring program at HartRAO is used as motivation for the design and development of a new low cost, multi-purpose digital pulsar receiver. The instrument is implemented using a hybrid filterbank architecture, consisting of an analogue frontend and digital backend, to perform incoherent dedispersion. The design of a polyphase filtering system, which will consolidate multiple processing units into a single filtering solution, is discussed for future implementation.
- Full Text:
- Date Issued: 2005