Prevalence of Escherichia coli O157:H7 in water and meat and meat products and vegetables sold in the Eastern Cape Province of South Africa and its impact on the diarrhoeic conditions of HIV/AIDS patients
- Authors: Abong'o, Benard Omondi
- Date: 2008
- Subjects: Foodborne diseases , Diarrhea , Escherichia coli , HIV infections , AIDS (Disease) , Bacterial diseases
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11263 , http://hdl.handle.net/10353/87 , Foodborne diseases , Diarrhea , Escherichia coli , HIV infections , AIDS (Disease) , Bacterial diseases
- Description: Water and food borne Escherichia coli O157:H7 could be one of the pathogens posing high health risk to patients suffering from Acquired Immunodeficiency Syndrome (AIDS) because of its incrimination in diarrhoea cases in AIDS patients. The present study, which was conducted between March 2005 and August 2006, investigated the prevalence of E. coli O157:H7 in water, meat and meat products and vegetables and its impact on diarrhoeic conditions of confirmed and non-confirmed HIV/AIDS patients in the Amathole District in the Eastern Cape Province of South Africa. The water samples used in the study were obtained from stand pipes supplying treated drinking water to communities residing in Fort Beaufort, Alice, Dimbaza and Mdantsane whereas borehole waters were sampled from Ngwenya and Kwasaki. The meat and meat products and vegetable samples were purchased from shops, butcheries, supermarkets and open air markets in Fort Beaufort, Alice and Mdantsane. The stool swabs used in the study were obtained from HIV/AIDS and outpatient clinics at Frere Hospital in East London. A total of 180 each of water, meat and meat products and vegetable samples and another 360 stool samples were analyzed for E. coli O157:H7. Presumptive E. coli O157 was isolated from the samples by culture-based methods and confirmed using Polymerase Chain Reaction techniques. Anti-biogram as well as risk assessment were also carried out using standard methods. The viable counts of presumptive E. coli O157 for water samples ranged between 3.3 × 104 and 1.71 × 105 CFU/ml, and between 1.8 × 104 and 5.04 × 106 CFU/g for meat and meat products, whereas those for vegetables ranged between 1.3 × 103 and 1.6 × 106 CFU/g. The counts of presumptive E. coli O157 for the water and vegetable samples were not significantly different whereas those for meat and meat products were found to be significantly different (P ≤ 0.05). The prevalence rates of presumptive E coli O157 in meat and meat products was 35.55 percent (64/180), and 25.55 percent (46/180) and 21.66 percent (39/180) for water and vegetables respectively. Prevalence of presumptive E. coli O157 in the stool samples of HIV/AIDS patients was 36.39 percent (131/360), of which 56.5 percent (74/131) and 43.5 percent (57/131) were from stools of confirmed and non-confirmed HIV/AIDS patients, respectively. Molecular analysis of representative presumptive E. coli O157 indicated that 10.29 percent (4/39) of vegetables; 14.81 percent (4/27) of water and 38.46 percent (5/13) of meat and meat products carried E. coli O157:H7. Also 36 percent (9/25) and 17.24 percent (5/29) of the stool samples were positive for E. coli O157:H7. Antimicrobial susceptibility profile revealed that all of the E. coli O157:H7 isolated from water, meat and meat products and vegetables as well as those isolated from stools of confirmed and non-confirmed HIV/AIDS patients were resistant (R) to gentamycin and erythromycin. However, 75 percent (20/27) of these isolates were resistant (R) to ampicillin and tetracycline whereas approximately 25 percent (6/27) were resistant (R) to nalidixic acid, ceftriaxone, and chloramphenicol. All the isolates (27/27) were susceptible (S) to amikacin. Probability of risk of E. coli O157:H7 infection was high for confirmed HIV/AIDS patients than for the non-confirmed HIV/AIDS patients. Estimated probability of risk of E. coli O157:H7 due to ingestion of water was 1.00 for 100 confirmed and non-confirmed HIV/AIDS patients. Risk due to meat and meat products was estimated at 0.27 and 0.20 and for vegetables at 0.21 and 0.15 per 100 confirmed and non-confirmed HIV/AIDS patients. The findings of this study predicted a possible link between E. coli O157:H7 isolated from drinking water, meat and meat products and vegetables and diarrhoeic conditions in both confirmed and non-confirmed HIV/AIDS patients, and concludes that confirmed HIV/AIDS patients can be at higher risk of contracting water and food borne E. coli O157:H7 than nonconfirmed HIV/AIDS patients. It is thus recommended that proper water treatment and food handling, maximum food and water safety and sanitation as well as personal body hygiene should be maintained, in order to prevent E. coli O157:H7 infections. Education initiatives and active surveillance of E. coli O157:H7 should be taken by all the stake-holders working directly or indirectly towards ensuring enduring sound public health.
- Full Text:
- Date Issued: 2008
- Authors: Abong'o, Benard Omondi
- Date: 2008
- Subjects: Foodborne diseases , Diarrhea , Escherichia coli , HIV infections , AIDS (Disease) , Bacterial diseases
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11263 , http://hdl.handle.net/10353/87 , Foodborne diseases , Diarrhea , Escherichia coli , HIV infections , AIDS (Disease) , Bacterial diseases
- Description: Water and food borne Escherichia coli O157:H7 could be one of the pathogens posing high health risk to patients suffering from Acquired Immunodeficiency Syndrome (AIDS) because of its incrimination in diarrhoea cases in AIDS patients. The present study, which was conducted between March 2005 and August 2006, investigated the prevalence of E. coli O157:H7 in water, meat and meat products and vegetables and its impact on diarrhoeic conditions of confirmed and non-confirmed HIV/AIDS patients in the Amathole District in the Eastern Cape Province of South Africa. The water samples used in the study were obtained from stand pipes supplying treated drinking water to communities residing in Fort Beaufort, Alice, Dimbaza and Mdantsane whereas borehole waters were sampled from Ngwenya and Kwasaki. The meat and meat products and vegetable samples were purchased from shops, butcheries, supermarkets and open air markets in Fort Beaufort, Alice and Mdantsane. The stool swabs used in the study were obtained from HIV/AIDS and outpatient clinics at Frere Hospital in East London. A total of 180 each of water, meat and meat products and vegetable samples and another 360 stool samples were analyzed for E. coli O157:H7. Presumptive E. coli O157 was isolated from the samples by culture-based methods and confirmed using Polymerase Chain Reaction techniques. Anti-biogram as well as risk assessment were also carried out using standard methods. The viable counts of presumptive E. coli O157 for water samples ranged between 3.3 × 104 and 1.71 × 105 CFU/ml, and between 1.8 × 104 and 5.04 × 106 CFU/g for meat and meat products, whereas those for vegetables ranged between 1.3 × 103 and 1.6 × 106 CFU/g. The counts of presumptive E. coli O157 for the water and vegetable samples were not significantly different whereas those for meat and meat products were found to be significantly different (P ≤ 0.05). The prevalence rates of presumptive E coli O157 in meat and meat products was 35.55 percent (64/180), and 25.55 percent (46/180) and 21.66 percent (39/180) for water and vegetables respectively. Prevalence of presumptive E. coli O157 in the stool samples of HIV/AIDS patients was 36.39 percent (131/360), of which 56.5 percent (74/131) and 43.5 percent (57/131) were from stools of confirmed and non-confirmed HIV/AIDS patients, respectively. Molecular analysis of representative presumptive E. coli O157 indicated that 10.29 percent (4/39) of vegetables; 14.81 percent (4/27) of water and 38.46 percent (5/13) of meat and meat products carried E. coli O157:H7. Also 36 percent (9/25) and 17.24 percent (5/29) of the stool samples were positive for E. coli O157:H7. Antimicrobial susceptibility profile revealed that all of the E. coli O157:H7 isolated from water, meat and meat products and vegetables as well as those isolated from stools of confirmed and non-confirmed HIV/AIDS patients were resistant (R) to gentamycin and erythromycin. However, 75 percent (20/27) of these isolates were resistant (R) to ampicillin and tetracycline whereas approximately 25 percent (6/27) were resistant (R) to nalidixic acid, ceftriaxone, and chloramphenicol. All the isolates (27/27) were susceptible (S) to amikacin. Probability of risk of E. coli O157:H7 infection was high for confirmed HIV/AIDS patients than for the non-confirmed HIV/AIDS patients. Estimated probability of risk of E. coli O157:H7 due to ingestion of water was 1.00 for 100 confirmed and non-confirmed HIV/AIDS patients. Risk due to meat and meat products was estimated at 0.27 and 0.20 and for vegetables at 0.21 and 0.15 per 100 confirmed and non-confirmed HIV/AIDS patients. The findings of this study predicted a possible link between E. coli O157:H7 isolated from drinking water, meat and meat products and vegetables and diarrhoeic conditions in both confirmed and non-confirmed HIV/AIDS patients, and concludes that confirmed HIV/AIDS patients can be at higher risk of contracting water and food borne E. coli O157:H7 than nonconfirmed HIV/AIDS patients. It is thus recommended that proper water treatment and food handling, maximum food and water safety and sanitation as well as personal body hygiene should be maintained, in order to prevent E. coli O157:H7 infections. Education initiatives and active surveillance of E. coli O157:H7 should be taken by all the stake-holders working directly or indirectly towards ensuring enduring sound public health.
- Full Text:
- Date Issued: 2008
A comparative analysis of the rights of the child with particular reference to child soldiers
- Authors: Anwo, Joel Olasunkanmi
- Date: 2008
- Subjects: Children's rights -- Child welfare -- Demobilization of children , Disarmament -- Reintegration
- Language: English
- Type: Thesis , Doctoral , LLD
- Identifier: vital:11108 , http://hdl.handle.net/10353/102 , Children's rights -- Child welfare -- Demobilization of children , Disarmament -- Reintegration
- Description: The recruitment, enlistment and forceful conscription of children as soldiers is a cause for grave concern all over the world and most especially in Africa, where years of factional fighting, civil wars and cross border conflicts have raged, children and youth have been pulled into violence not only as victims, but also as perpetrators. The involvement of children in war posses a severe challenge to prevailing moral and legal norms of the conduct of modern warfare. A major problem and most controversial issue, among others, is on the age at which children should be eligible to become combatants. Children, who may be viewed as a valuable resource due to their often inherent malleability, wish to avenge family member(s) killed in war, sense of immunity to danger, and or feeling of power in participating in the violence. Can the use of children as soldiers be effectively regulated in Africa? All efforts to assist child soldiers in recovering from the devastating effects of wars often unwillingly helped promote the growing number of child soldiers. This is in part because wars are now more fought internally among rebel armies and factions vying for power with the government and thus enlist children into their various armies. The study comes to a conclusion that drastic steps need to be taken to ameliorate this unfortunate situation. This formed the basis of the recommendations offered in the thesis to assist the African continent.
- Full Text:
- Date Issued: 2008
- Authors: Anwo, Joel Olasunkanmi
- Date: 2008
- Subjects: Children's rights -- Child welfare -- Demobilization of children , Disarmament -- Reintegration
- Language: English
- Type: Thesis , Doctoral , LLD
- Identifier: vital:11108 , http://hdl.handle.net/10353/102 , Children's rights -- Child welfare -- Demobilization of children , Disarmament -- Reintegration
- Description: The recruitment, enlistment and forceful conscription of children as soldiers is a cause for grave concern all over the world and most especially in Africa, where years of factional fighting, civil wars and cross border conflicts have raged, children and youth have been pulled into violence not only as victims, but also as perpetrators. The involvement of children in war posses a severe challenge to prevailing moral and legal norms of the conduct of modern warfare. A major problem and most controversial issue, among others, is on the age at which children should be eligible to become combatants. Children, who may be viewed as a valuable resource due to their often inherent malleability, wish to avenge family member(s) killed in war, sense of immunity to danger, and or feeling of power in participating in the violence. Can the use of children as soldiers be effectively regulated in Africa? All efforts to assist child soldiers in recovering from the devastating effects of wars often unwillingly helped promote the growing number of child soldiers. This is in part because wars are now more fought internally among rebel armies and factions vying for power with the government and thus enlist children into their various armies. The study comes to a conclusion that drastic steps need to be taken to ameliorate this unfortunate situation. This formed the basis of the recommendations offered in the thesis to assist the African continent.
- Full Text:
- Date Issued: 2008
A model for sustainable operational excellence through knowledge management practices and continuous improvement principles
- Beeken, Wilhelm Frederik Hartmann
- Authors: Beeken, Wilhelm Frederik Hartmann
- Date: 2008
- Subjects: Organizational effectiveness , Knowledge management
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: vital:8699 , http://hdl.handle.net/10948/1061 , Organizational effectiveness , Knowledge management
- Description: Integrating Knowledge Management maturity with associated Continuous Improvement efforts in order to remain competitive, is absent in most Operational Excellence initiatives. Furthermore, the intertwined relationship of Continuous Improvement and work development becomes a crucial focus area for organisations that wish to establish a continuously evolving management system consisting of core values, methodologies and tools with the aim of creating more satisfied customers with less resources. The old industrial paradigm that focused on labour, capital, materials, and energy viewed technology and knowledge as external influences on production. This framework is now being challenged and a new trend is emerging. This trend seeks to transform the old industrial system to that of a knowledge-based which one can lead to innovation and hence economic advantage. Continuous Improvement as a concept has roots in many other fields, including social-technical system design, human relations progress and the discussion surrounding ‘lean manufacturing’. This study will focus on Continuous Improvement as a noun, referring to on the outcome of the process of a stream of emergent innovations. The primary objective of the study is to create a model that will present an organisation with a three-layer knowledge reference process grid, which will align and depict the surrounding business knowledge functions, knowledge-enabling processes and knowledge-manipulating processes aiming for enabling Operational Excellence. This study promotes the theory that the cognitive domain layer, functional domain layer and resources layer of an organisation can be increasingly stimulated by focusing effort through Continuous Improvement routines towards the associated inter-organisational knowledge processes sustaining Operational Excellence. The proposed model is structured to review, compare, evaluate and integrate existing Knowledge Management practices of ii an organisation within the context of clear definitions for important concepts of Knowledge Management. Additionally the model provides an assessment instrument for evaluating the organisation’s Knowledge Management maturity level. The study concerns itself with two concepts towards business value creation which will lead to increased Operational Excellence. Firstly, the maturity of Knowledge Management processes, and secondly the level of the organisation wide process of focused and continuous incremental improvement namely, Continuous Improvement. A case study with PriceWaterhouseCoopers was concluded and an on-line Internet survey was used with a stratified sample from knowledge workers to test the factors from both a Knowledge Management and Continuous Improvement perspective. These factors were verified by means of a hypotheses network, describing in a structured and descriptive way, the importance of Knowledge Management and Continuous Improvement collectively on sustainable Operational Excellence as an integral development of Operational Excellence. With respect to Knowledge Management practices, the hypothesis network proposed at least three domains, which of knowledge generation, knowledge mobilisation and knowledge application as important input to the proposed process grid of knowledge development and associated layer elements. From a Continuous Improvement principles perspective it is apparent that elements from Continuous Improvement routines and Continuous Improvement characteristics are associated with the organisation Continuous Improvement ability. These findings are also a result of the deliberate design of processes, tools, structures and environments with the intent to increase, renew, share or improve the use of knowledge represented in any of the three elements for structural, human and social of intellectual capital. The proposed model combines the framework of the Boyd cycle as it is conceptualized as self-assessment activities, for it becomes possible to use them as basis of a self-assessment with sense making navigational properties across iii the proposed knowledge process grid for the model. The model will facilitate the concept of a three-layer knowledge reference process grid, which represents the main components of the knowledge processes within the cognitive domain layer, functional layer and resources layer of an organisation. The proposed model will deliver a single value that co-exists with the Knowledge Management maturity level and Continuous Improvement readiness index rating attained. Logical relationships to dynamic, evolving and flexible enabling Knowledge Management practices for each layer of the proposed three-layer knowledge reference process grid will be integrated as output of the proposed model. The research has limitations as Knowledge Management practices were measured using a subjective norm scale. It is suggested that a more comprehensive measure of Knowledge Management maturity processes may be needed to represent this construct. The complexity of the proposed model and the number of associated variables included in the results need further confirmation using possible multiple samples and additional measures of Knowledge Management maturity and Continuous Improvement readiness elements. The benefit of the proposed model as a practical Operational Excellence tool is to overcome the perceived gap of implementing Knowledge Management practices and Continuous Improvement principles collectively to deliver and sustain Operational Excellence.
- Full Text:
- Date Issued: 2008
- Authors: Beeken, Wilhelm Frederik Hartmann
- Date: 2008
- Subjects: Organizational effectiveness , Knowledge management
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: vital:8699 , http://hdl.handle.net/10948/1061 , Organizational effectiveness , Knowledge management
- Description: Integrating Knowledge Management maturity with associated Continuous Improvement efforts in order to remain competitive, is absent in most Operational Excellence initiatives. Furthermore, the intertwined relationship of Continuous Improvement and work development becomes a crucial focus area for organisations that wish to establish a continuously evolving management system consisting of core values, methodologies and tools with the aim of creating more satisfied customers with less resources. The old industrial paradigm that focused on labour, capital, materials, and energy viewed technology and knowledge as external influences on production. This framework is now being challenged and a new trend is emerging. This trend seeks to transform the old industrial system to that of a knowledge-based which one can lead to innovation and hence economic advantage. Continuous Improvement as a concept has roots in many other fields, including social-technical system design, human relations progress and the discussion surrounding ‘lean manufacturing’. This study will focus on Continuous Improvement as a noun, referring to on the outcome of the process of a stream of emergent innovations. The primary objective of the study is to create a model that will present an organisation with a three-layer knowledge reference process grid, which will align and depict the surrounding business knowledge functions, knowledge-enabling processes and knowledge-manipulating processes aiming for enabling Operational Excellence. This study promotes the theory that the cognitive domain layer, functional domain layer and resources layer of an organisation can be increasingly stimulated by focusing effort through Continuous Improvement routines towards the associated inter-organisational knowledge processes sustaining Operational Excellence. The proposed model is structured to review, compare, evaluate and integrate existing Knowledge Management practices of ii an organisation within the context of clear definitions for important concepts of Knowledge Management. Additionally the model provides an assessment instrument for evaluating the organisation’s Knowledge Management maturity level. The study concerns itself with two concepts towards business value creation which will lead to increased Operational Excellence. Firstly, the maturity of Knowledge Management processes, and secondly the level of the organisation wide process of focused and continuous incremental improvement namely, Continuous Improvement. A case study with PriceWaterhouseCoopers was concluded and an on-line Internet survey was used with a stratified sample from knowledge workers to test the factors from both a Knowledge Management and Continuous Improvement perspective. These factors were verified by means of a hypotheses network, describing in a structured and descriptive way, the importance of Knowledge Management and Continuous Improvement collectively on sustainable Operational Excellence as an integral development of Operational Excellence. With respect to Knowledge Management practices, the hypothesis network proposed at least three domains, which of knowledge generation, knowledge mobilisation and knowledge application as important input to the proposed process grid of knowledge development and associated layer elements. From a Continuous Improvement principles perspective it is apparent that elements from Continuous Improvement routines and Continuous Improvement characteristics are associated with the organisation Continuous Improvement ability. These findings are also a result of the deliberate design of processes, tools, structures and environments with the intent to increase, renew, share or improve the use of knowledge represented in any of the three elements for structural, human and social of intellectual capital. The proposed model combines the framework of the Boyd cycle as it is conceptualized as self-assessment activities, for it becomes possible to use them as basis of a self-assessment with sense making navigational properties across iii the proposed knowledge process grid for the model. The model will facilitate the concept of a three-layer knowledge reference process grid, which represents the main components of the knowledge processes within the cognitive domain layer, functional layer and resources layer of an organisation. The proposed model will deliver a single value that co-exists with the Knowledge Management maturity level and Continuous Improvement readiness index rating attained. Logical relationships to dynamic, evolving and flexible enabling Knowledge Management practices for each layer of the proposed three-layer knowledge reference process grid will be integrated as output of the proposed model. The research has limitations as Knowledge Management practices were measured using a subjective norm scale. It is suggested that a more comprehensive measure of Knowledge Management maturity processes may be needed to represent this construct. The complexity of the proposed model and the number of associated variables included in the results need further confirmation using possible multiple samples and additional measures of Knowledge Management maturity and Continuous Improvement readiness elements. The benefit of the proposed model as a practical Operational Excellence tool is to overcome the perceived gap of implementing Knowledge Management practices and Continuous Improvement principles collectively to deliver and sustain Operational Excellence.
- Full Text:
- Date Issued: 2008
The feeding and spatial ecologies of the large carnivore guild on Kwandwe Private Game Reserve
- Authors: Bissett, Charlene
- Date: 2008
- Subjects: Wildlife conservation -- South Africa -- Eastern Cape Kwandwe Private Game Reserve Lion -- Behavior -- South Africa -- Eastern Cape Lion -- Nutrition -- South Africa -- Eastern Cape Cheetah -- Behavior -- South Africa -- Eastern Cape Cheetah -- Nutrition -- South Africa -- Eastern Cape African wild dog -- South Africa -- Eastern Cape Spatial behavior in animals Predation (Biology) Game reserves -- Management
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5802 , http://hdl.handle.net/10962/d1006195
- Description: The reintroduction of lions, cheetahs and African wild dogs to Kwandwe Private Game Reserve in the Eastern Cape Province of South Africa created the opportunity to study the biology and behaviour of these large carnivores in an enclosed system. The research focused on space utilisation and feeding ecology of the predators, using standard observational methods. Changes in the structure of the carnivore guild, and changes in the prey base that occurred during the study were used as natural experiments to examine factors affecting space use and diet. In general, the diets of the predators were similar to previous studies and prey abundance was more important than prey species size in determining prey selection. Changes in the abundance of certain prey species was matched by a dietary switch in lions from kudu to warthog and an increase in the proportion of springbok kills by the cheetahs. There was no significant difference in the proportions of prey species detected by ad hoc or continuous observations. Core areas occupied by the predators were significantly smaller than home ranges except when females were denning. Home ranges overlapped both within and between species, but there was very little overlap of core areas. An increase in the number of lion prides in the area during the study resulted in an increase in overlap of home ranges of lions and cheetahs, but did not result in a change in home range size. Space use by female cheetahs with cubs increased as the cubs grew older. The use of thicket vegetation by cheetahs decreased with an increase in the number of lion prides. Minimum Daily Energy Expenditure, energy intake and net benefit were calculated for the predators using data from continuous observations. All predators exhibited a large net benefit and the net benefit for single female cheetahs was greater than for the members of the coalition. Net benefit for the alpha pair of African wild dogs was lower than that of the pack.
- Full Text:
- Date Issued: 2008
- Authors: Bissett, Charlene
- Date: 2008
- Subjects: Wildlife conservation -- South Africa -- Eastern Cape Kwandwe Private Game Reserve Lion -- Behavior -- South Africa -- Eastern Cape Lion -- Nutrition -- South Africa -- Eastern Cape Cheetah -- Behavior -- South Africa -- Eastern Cape Cheetah -- Nutrition -- South Africa -- Eastern Cape African wild dog -- South Africa -- Eastern Cape Spatial behavior in animals Predation (Biology) Game reserves -- Management
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5802 , http://hdl.handle.net/10962/d1006195
- Description: The reintroduction of lions, cheetahs and African wild dogs to Kwandwe Private Game Reserve in the Eastern Cape Province of South Africa created the opportunity to study the biology and behaviour of these large carnivores in an enclosed system. The research focused on space utilisation and feeding ecology of the predators, using standard observational methods. Changes in the structure of the carnivore guild, and changes in the prey base that occurred during the study were used as natural experiments to examine factors affecting space use and diet. In general, the diets of the predators were similar to previous studies and prey abundance was more important than prey species size in determining prey selection. Changes in the abundance of certain prey species was matched by a dietary switch in lions from kudu to warthog and an increase in the proportion of springbok kills by the cheetahs. There was no significant difference in the proportions of prey species detected by ad hoc or continuous observations. Core areas occupied by the predators were significantly smaller than home ranges except when females were denning. Home ranges overlapped both within and between species, but there was very little overlap of core areas. An increase in the number of lion prides in the area during the study resulted in an increase in overlap of home ranges of lions and cheetahs, but did not result in a change in home range size. Space use by female cheetahs with cubs increased as the cubs grew older. The use of thicket vegetation by cheetahs decreased with an increase in the number of lion prides. Minimum Daily Energy Expenditure, energy intake and net benefit were calculated for the predators using data from continuous observations. All predators exhibited a large net benefit and the net benefit for single female cheetahs was greater than for the members of the coalition. Net benefit for the alpha pair of African wild dogs was lower than that of the pack.
- Full Text:
- Date Issued: 2008
Novel aspects of platinum-amine coordination compounds: their chemistry and anticancer application
- Authors: Bouwer, Yolanda
- Date: 2008
- Subjects: Coordination compounds , Platinum compounds , Antineoplastic agents
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10444 , http://hdl.handle.net/10948/d1021052
- Description: The aim in this thesis, was to synthesize novel platinum coordination compounds, in order to develop compounds with improved anticancer action which could lead to an improved understanding of the mechanism by which they operate and at the same time, improve synthetic methods for their products. The initial work included the development of a novel synthetic method for 1R,2R-diaminocyclohexaneoxalato-platinum(II) (oxaliplatin), by using an essentially non-aqueous solvent medium and direct ligand exchange at elevated temperatures. This was done by a study of the kinetics of the reaction in a variety of conditions; such as relative reagent concentrations and ratios as well as solvent mixtures. An effective method was developed which could be applied industrially. An international patent was taken out on this method. Various amine complexes of platinum(II) were synthesized using chloro, bromo and oxalato groups as leaving groups. The non-leaving groups were selected having certain specific characteristics in mind. Novel mononitroplatinum(IV) complexes were synthesized, mostly with oxalato leaving groups. One of these in particular, had excellent anticancer behaviour. Another trichloromononitro complex was also synthesized with very good anticancer properties. Two international patents were filed for the latter two compounds. As far as possible, all compounds were studied by spectrometric, chromatographic and thermal methods. They were also tested against 3 cancer cell lines namely cervical (Hela), Colon (HT29) and Breast (MCF7) cancer cells.
- Full Text:
- Date Issued: 2008
- Authors: Bouwer, Yolanda
- Date: 2008
- Subjects: Coordination compounds , Platinum compounds , Antineoplastic agents
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10444 , http://hdl.handle.net/10948/d1021052
- Description: The aim in this thesis, was to synthesize novel platinum coordination compounds, in order to develop compounds with improved anticancer action which could lead to an improved understanding of the mechanism by which they operate and at the same time, improve synthetic methods for their products. The initial work included the development of a novel synthetic method for 1R,2R-diaminocyclohexaneoxalato-platinum(II) (oxaliplatin), by using an essentially non-aqueous solvent medium and direct ligand exchange at elevated temperatures. This was done by a study of the kinetics of the reaction in a variety of conditions; such as relative reagent concentrations and ratios as well as solvent mixtures. An effective method was developed which could be applied industrially. An international patent was taken out on this method. Various amine complexes of platinum(II) were synthesized using chloro, bromo and oxalato groups as leaving groups. The non-leaving groups were selected having certain specific characteristics in mind. Novel mononitroplatinum(IV) complexes were synthesized, mostly with oxalato leaving groups. One of these in particular, had excellent anticancer behaviour. Another trichloromononitro complex was also synthesized with very good anticancer properties. Two international patents were filed for the latter two compounds. As far as possible, all compounds were studied by spectrometric, chromatographic and thermal methods. They were also tested against 3 cancer cell lines namely cervical (Hela), Colon (HT29) and Breast (MCF7) cancer cells.
- Full Text:
- Date Issued: 2008
A historic-hermeneutic critique of luthiery with specific reference to selected South African guiter builders
- Authors: Bower, Rudi
- Date: 2008
- Subjects: Guitar -- Construction , Guitar -- History
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8512 , http://hdl.handle.net/10948/779 , Guitar -- Construction , Guitar -- History
- Description: This study uses a general historical overview of luthiery that provides the reader with a basic understanding of construction techniques and terminology as a point of departure. From the outset the lack of consensus over an ideal or desired construction technique is highlighted. However, Torres is credited with the establishing of a perceived Spanish tradition of guitar construction and acknowledged as the “father” of the modern guitar. This will serve as a basic framework in which a discussion of six prominent past and present international luthiers can occur. These luthiers, namely Antonio de Torres, Hermann Hauser, Robert Bouchet, Daniel Friederich, Jose Romanillos and Greg Smallman are included in this study by virtue of their influence on the South African luthiers that are featured here. It is noted that these six luthiers, with the exception of Greg Smallman, all adhere to the “Spanish tradition” of guitar construction. Smallman can be considered a foremost proponent of a more recent “modern” school of guitar construction characterized by various innovative construction techniques. These are a result of new demands placed on the guitar as performance instrument because of larger concert venues and more collaboration with different instruments, resulting in a need for a stronger tone and more projection and penetration in sound. These two “poles” of luthiery are then manifested in the discussion on the seven featured South African luthiers. Alistair Thompson, Colin Cleveland, Mervyn Davis, Garth Pickard, Marc Maingard, Rodney Stedall and Hans van den Berg are discussed with special mention made of the features of their instruments, woods used and thoughts on luthiery, against the backdrop of their biographies. The four South African luthiers who build within the “Spanish tradition” (Pickard, Maingard, Stedall and Van den Berg) are distinguished from the three who build outside this so-called tradition (Thompson, Cleveland, Davis). South African luthiery is therefore shown to be an accurate microcosm of luthiery in global terms with styles of construction ranging from very “traditional” to very “modern”. The critical reflection on the information contained in this study appears in the form of a hermeneutic critique on luthiery that occurs within the parameters of the thought of two prominent hermeneutic thinkers, Martin Heidegger and his student, Hans-Georg Gadamer. It is shown that the collaboration that often occurs between guitar makers and performers can be related back to Gadamer and his analysis of Heidegger’s notion of the the hermeneutic circle. It is also argued that luthiery as practiced by the international and South African luthiers featured in this study can be seen both as art and technology in ancient Greek terms in that they are both a mode of revealing. Finally, it is shown how luthiery in its entirety can be viewed as a tradition and that different luthiers respond and add to this tradition in various ways.
- Full Text:
- Date Issued: 2008
- Authors: Bower, Rudi
- Date: 2008
- Subjects: Guitar -- Construction , Guitar -- History
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8512 , http://hdl.handle.net/10948/779 , Guitar -- Construction , Guitar -- History
- Description: This study uses a general historical overview of luthiery that provides the reader with a basic understanding of construction techniques and terminology as a point of departure. From the outset the lack of consensus over an ideal or desired construction technique is highlighted. However, Torres is credited with the establishing of a perceived Spanish tradition of guitar construction and acknowledged as the “father” of the modern guitar. This will serve as a basic framework in which a discussion of six prominent past and present international luthiers can occur. These luthiers, namely Antonio de Torres, Hermann Hauser, Robert Bouchet, Daniel Friederich, Jose Romanillos and Greg Smallman are included in this study by virtue of their influence on the South African luthiers that are featured here. It is noted that these six luthiers, with the exception of Greg Smallman, all adhere to the “Spanish tradition” of guitar construction. Smallman can be considered a foremost proponent of a more recent “modern” school of guitar construction characterized by various innovative construction techniques. These are a result of new demands placed on the guitar as performance instrument because of larger concert venues and more collaboration with different instruments, resulting in a need for a stronger tone and more projection and penetration in sound. These two “poles” of luthiery are then manifested in the discussion on the seven featured South African luthiers. Alistair Thompson, Colin Cleveland, Mervyn Davis, Garth Pickard, Marc Maingard, Rodney Stedall and Hans van den Berg are discussed with special mention made of the features of their instruments, woods used and thoughts on luthiery, against the backdrop of their biographies. The four South African luthiers who build within the “Spanish tradition” (Pickard, Maingard, Stedall and Van den Berg) are distinguished from the three who build outside this so-called tradition (Thompson, Cleveland, Davis). South African luthiery is therefore shown to be an accurate microcosm of luthiery in global terms with styles of construction ranging from very “traditional” to very “modern”. The critical reflection on the information contained in this study appears in the form of a hermeneutic critique on luthiery that occurs within the parameters of the thought of two prominent hermeneutic thinkers, Martin Heidegger and his student, Hans-Georg Gadamer. It is shown that the collaboration that often occurs between guitar makers and performers can be related back to Gadamer and his analysis of Heidegger’s notion of the the hermeneutic circle. It is also argued that luthiery as practiced by the international and South African luthiers featured in this study can be seen both as art and technology in ancient Greek terms in that they are both a mode of revealing. Finally, it is shown how luthiery in its entirety can be viewed as a tradition and that different luthiers respond and add to this tradition in various ways.
- Full Text:
- Date Issued: 2008
Melatonin and anticancer therapy interactions with 5-Fluorouracil
- Authors: Cassim, Layla
- Date: 2008
- Subjects: Melatonin Melatonin -- Therapeutic use Antineoplastic agents Fluorouracil Fluorouracil -- Toxicology Cancer -- Treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3746 , http://hdl.handle.net/10962/d1003224
- Description: On the basis of clinical studies, some researchers have advocated that the neurohormone and antioxidant melatonin, shown to possess intrinsic anticancer properties, be used as co-therapy in cancer patients being treated with the antineoplastic agent 5-fluorouracil, as increased patient survival times and enhanced quality of life have been observed. The focus of this research was thus to investigate the mechanisms of this seemingly beneficial drug interaction between 5-fluorouracil and melatonin. Metabolism studies were undertaken, in which it was established that there is no hepatic metabolic drug interaction between these agents by cytochrome P450, and that neither agent alters the activity of this enzyme system. Co-therapy with melatonin is thus unlikely to alter plasma levels of 5-fluorouracil by this mechanism. Novel mechanisms by which 5-fluorouracil is toxic were elucidated, such as the induction of lipid peroxidation, due to the formation of reactive oxygen species; decreases in brain serotonin, dopamine and norepinephrine levels, possibly leading to depression; hippocampal shrinkage and morphological alterations and lysis of hippocampal cells, which may underlie cognitive impairment; and a reduction in the nociceptive threshold when administered acutely. All these deleterious effects are attenuated by the co-administration of melatonin, suggesting that the agent exhibits antidepressive and analgesic properties, in addition to its known antioxidative and free radical-scavenging abilities. This suggests that melatonin cotherapy can significantly decrease 5-fluorouracil-induced toxicity, but this may also exert a protective effect on cancer cells and thus compromise the anticancer efficacy of 5-fluorouracil. It was, furthermore, found that stimulation of indoleamine 2,3-dioxygenase activity, mediated by increases in superoxide anion and interferon-γ levels, may underlie resistance to 5-fluorouracil therapy. Melatonin was shown to increase superoxide anion levels in vivo, and this is believed to be by conversion to the metabolite and known oxidant 6- hydroxymelatonin. This highlights that the possible deleterious effects of melatonin metabolites should be studied further. Serum corticosterone levels and cytokine profiles are unaltered by both 5-FU and melatonin, suggesting that these agents may be used by HIV infected individuals without promoting the progression to AIDS. It can thus be concluded that melatonin co-therapy is potentially useful in countering 5-fluorouracil toxicity.
- Full Text:
- Date Issued: 2008
- Authors: Cassim, Layla
- Date: 2008
- Subjects: Melatonin Melatonin -- Therapeutic use Antineoplastic agents Fluorouracil Fluorouracil -- Toxicology Cancer -- Treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3746 , http://hdl.handle.net/10962/d1003224
- Description: On the basis of clinical studies, some researchers have advocated that the neurohormone and antioxidant melatonin, shown to possess intrinsic anticancer properties, be used as co-therapy in cancer patients being treated with the antineoplastic agent 5-fluorouracil, as increased patient survival times and enhanced quality of life have been observed. The focus of this research was thus to investigate the mechanisms of this seemingly beneficial drug interaction between 5-fluorouracil and melatonin. Metabolism studies were undertaken, in which it was established that there is no hepatic metabolic drug interaction between these agents by cytochrome P450, and that neither agent alters the activity of this enzyme system. Co-therapy with melatonin is thus unlikely to alter plasma levels of 5-fluorouracil by this mechanism. Novel mechanisms by which 5-fluorouracil is toxic were elucidated, such as the induction of lipid peroxidation, due to the formation of reactive oxygen species; decreases in brain serotonin, dopamine and norepinephrine levels, possibly leading to depression; hippocampal shrinkage and morphological alterations and lysis of hippocampal cells, which may underlie cognitive impairment; and a reduction in the nociceptive threshold when administered acutely. All these deleterious effects are attenuated by the co-administration of melatonin, suggesting that the agent exhibits antidepressive and analgesic properties, in addition to its known antioxidative and free radical-scavenging abilities. This suggests that melatonin cotherapy can significantly decrease 5-fluorouracil-induced toxicity, but this may also exert a protective effect on cancer cells and thus compromise the anticancer efficacy of 5-fluorouracil. It was, furthermore, found that stimulation of indoleamine 2,3-dioxygenase activity, mediated by increases in superoxide anion and interferon-γ levels, may underlie resistance to 5-fluorouracil therapy. Melatonin was shown to increase superoxide anion levels in vivo, and this is believed to be by conversion to the metabolite and known oxidant 6- hydroxymelatonin. This highlights that the possible deleterious effects of melatonin metabolites should be studied further. Serum corticosterone levels and cytokine profiles are unaltered by both 5-FU and melatonin, suggesting that these agents may be used by HIV infected individuals without promoting the progression to AIDS. It can thus be concluded that melatonin co-therapy is potentially useful in countering 5-fluorouracil toxicity.
- Full Text:
- Date Issued: 2008
A reading based theory of teaching appropriate for the South African context
- Authors: Childs, Margaret Mary
- Date: 2008
- Subjects: Literacy , Language and languages -- Study and teaching -- South Africa , Communicative competence -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9485 , http://hdl.handle.net/10948/687 , Literacy , Language and languages -- Study and teaching -- South Africa , Communicative competence -- Study and teaching
- Description: The print literacy competencies of many South African teachers and the learners they teach are inadequate. Evidence from local and international evaluations and research attests to this. Based on the understanding that a teacher, whose literacy level is less than adequate, is in a weak position to teach others how to read and write, the imperative to systematically address the issue of poor teacher and learner literacy levels, provided the impetus for a careful investigation of the methodology and theory of the Learning to Read: Reading to Learn pedagogy. Originally developed in Australia and applied in primary, secondary and tertiary contexts, this literacy pedagogy was described as a means of rapidly improving the literacy competence of all learners, across all subject areas. Using an approach located within the tradition of interpretative educational theory, the meaning of the theory and practice of the Learning to Read: Reading to Learn pedagogy was explored. As a result of the enquiry undertaken, it was found that the Learning to Read: Reading to Learn approach provides a practical means of enhancing epistemological access. Access of this nature is a precondition for success of learning in schools and in tertiary education. The LR:RL pedagogy provides a carefully structured means of holding literacy at the centre of learning. The sequence of practical steps theoretically rooted in three powerful – but usually separate realms of discourse, is a central contribution of the pedagogy to field of literacy development. Intersecting three discrete disciplines, represented by Bernstein’s model of education as pedagogic discourse, Vygotsky’s model of learning as a social process and Halliday’s model of language as text in social context gives rise to a unique literacy pedagogy. The theory that emerges from use, in a range of situations, over many years, and the carefully sequenced practice, together offer a sound means of addressing the challenges of literacy and learning prevalent in the South African context. iii This thesis argues for a reading based theory of teaching as a means of meeting the challenges of literacy and learning head on. The capacity to learn independently from written text is critical for progress within the schooling and tertiary systems. The Learning to Read: Reading to Learn pedagogy provides a means of realizing such a theory of teaching. Simultaneously teaching print literacy, while teaching the content of curricula, is proposed as a way of bringing about effective learning. Within the context of teacher education, the pedagogical content knowledge (PCK) of many teachers is acknowledged to be inadequate. However, there is a key dimension missing for the construct of PCK to be truly useful for South African teachers. Print literacy is as an essential determinant of the knowledge of teachers. The construct of PCK can thus supplemented by foregrounding reading and writing as essential elements of this category of teacher knowledge. Thus the content of the teacher education curriculum is taught as the reading and writing competence of teachers is developed. Similarly, within the school context, the Learning to Read: Reading to Learn pedagogy can be used to teach required content and teach the requisite high level reading and writing skills needed by all learners to progress successfully through the schooling system.
- Full Text:
- Date Issued: 2008
- Authors: Childs, Margaret Mary
- Date: 2008
- Subjects: Literacy , Language and languages -- Study and teaching -- South Africa , Communicative competence -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9485 , http://hdl.handle.net/10948/687 , Literacy , Language and languages -- Study and teaching -- South Africa , Communicative competence -- Study and teaching
- Description: The print literacy competencies of many South African teachers and the learners they teach are inadequate. Evidence from local and international evaluations and research attests to this. Based on the understanding that a teacher, whose literacy level is less than adequate, is in a weak position to teach others how to read and write, the imperative to systematically address the issue of poor teacher and learner literacy levels, provided the impetus for a careful investigation of the methodology and theory of the Learning to Read: Reading to Learn pedagogy. Originally developed in Australia and applied in primary, secondary and tertiary contexts, this literacy pedagogy was described as a means of rapidly improving the literacy competence of all learners, across all subject areas. Using an approach located within the tradition of interpretative educational theory, the meaning of the theory and practice of the Learning to Read: Reading to Learn pedagogy was explored. As a result of the enquiry undertaken, it was found that the Learning to Read: Reading to Learn approach provides a practical means of enhancing epistemological access. Access of this nature is a precondition for success of learning in schools and in tertiary education. The LR:RL pedagogy provides a carefully structured means of holding literacy at the centre of learning. The sequence of practical steps theoretically rooted in three powerful – but usually separate realms of discourse, is a central contribution of the pedagogy to field of literacy development. Intersecting three discrete disciplines, represented by Bernstein’s model of education as pedagogic discourse, Vygotsky’s model of learning as a social process and Halliday’s model of language as text in social context gives rise to a unique literacy pedagogy. The theory that emerges from use, in a range of situations, over many years, and the carefully sequenced practice, together offer a sound means of addressing the challenges of literacy and learning prevalent in the South African context. iii This thesis argues for a reading based theory of teaching as a means of meeting the challenges of literacy and learning head on. The capacity to learn independently from written text is critical for progress within the schooling and tertiary systems. The Learning to Read: Reading to Learn pedagogy provides a means of realizing such a theory of teaching. Simultaneously teaching print literacy, while teaching the content of curricula, is proposed as a way of bringing about effective learning. Within the context of teacher education, the pedagogical content knowledge (PCK) of many teachers is acknowledged to be inadequate. However, there is a key dimension missing for the construct of PCK to be truly useful for South African teachers. Print literacy is as an essential determinant of the knowledge of teachers. The construct of PCK can thus supplemented by foregrounding reading and writing as essential elements of this category of teacher knowledge. Thus the content of the teacher education curriculum is taught as the reading and writing competence of teachers is developed. Similarly, within the school context, the Learning to Read: Reading to Learn pedagogy can be used to teach required content and teach the requisite high level reading and writing skills needed by all learners to progress successfully through the schooling system.
- Full Text:
- Date Issued: 2008
Molecular characterization of the Hsp70/Hsp90 organizing protein (Hop) phosphorylation, subcellular localization and interaction with Hsp90
- Authors: Daniel, Sheril
- Date: 2008
- Subjects: Molecular chaperones Phosphorylation Proteins Heat shock proteins Surface plasmon resonance Cytosol
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3996 , http://hdl.handle.net/10962/d1004056
- Description: Hop (Hsp70-Hsp90 Organizing Protein) is a co-chaperone of two major molecular chaperones, Hsp70 and Hsp90, and acts by transferring substrates from Hsp70 to Hsp90. Although under normal conditions Hop is predominantly localized within the cytosol, Hop has been detected in the nucleus under certain conditions including cell cycle arrest. A putative nuclear localization signal (NLS) has been identified within Hop, which overlaps with the TPR2A domain (previously shown to be critical for Hop-Hsp90 interactions). Hop is phosphorylated in vitro by two cell cycle kinases, namely, casein kinase II (CKII) at S189 and cdc2-kinase at T198; both residues are found upstream of the putative NLS and TPR2A domain. Mimicking phosphorylation at either phosphorylation site appeared to affect the subcellular localization of Hop. The aim of this study was to characterize Hop with respect to its phosphorylation status in vivo, as well as its subcellular localization pattern under heat stress and determine how these properties affected its interaction with Hsp90 as a co-chaperone. Dephosphorylation of proteins under normal and heat shock conditions changed the isoform composition of Hop, providing strong evidence that Hop was phosphorylated in vivo. Surface plasmon resonance (SPR) and glutatione-S-transferase (GST) co-precipitation studies showed that a cdc2-kinase phosphorylated mimic of Hop disrupted Hop-Hsp90 binding. A full length Hop-EGFP construct, as well as substitution mutants of the predicted NLS residues within the Hop-EGFP construct, were transfected into baby hamster kidney (BHK)-21 cells in order to establish the subcellular localization of Hop under heat stress and to test whether predicted residues were critical for nuclear localization of Hop. Under normal conditions, both Hop-EGFP and the NLS mutants were predominantly cytosolic, but when the cells were subjected to heat stress, Hop and its NLS-mutants were localized to both the cytosol and the nucleus. SPR and GST co-precipitation studies showed that substitution of the residues within the major arm of the putative NLS abrogated Hop-Hsp90 interactions. The data obtained from this study, showed for the first time, that Hop was phosphorylated in vivo and suggested that phosphorylation of Hop by cdc2-kinase could inhibit Hop-Hsp90 interactions. Moreover, these results suggested that the subcellular localization of Hop was dependent on stress levels of the cell, particularly heat stress. We propose that the nuclear localization of Hop may be primarily regulated by stress and secondarily by cell cycle arrest. The major arm of the putative NLS did not affect the localization of Hop directly, but was shown to be critical for Hop-Hsp90 binding in vitro. The results of this study suggested that binding of Hop to Hsp90 sequestered Hop within the cytosol and that Hsp90 acted as a cytosolic retention factor for Hop. Both phosphorylation of Hop, and its subcellular localization, appeared to be intimately related to its interaction with Hsp90 as a co-chaperone.
- Full Text:
- Date Issued: 2008
- Authors: Daniel, Sheril
- Date: 2008
- Subjects: Molecular chaperones Phosphorylation Proteins Heat shock proteins Surface plasmon resonance Cytosol
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3996 , http://hdl.handle.net/10962/d1004056
- Description: Hop (Hsp70-Hsp90 Organizing Protein) is a co-chaperone of two major molecular chaperones, Hsp70 and Hsp90, and acts by transferring substrates from Hsp70 to Hsp90. Although under normal conditions Hop is predominantly localized within the cytosol, Hop has been detected in the nucleus under certain conditions including cell cycle arrest. A putative nuclear localization signal (NLS) has been identified within Hop, which overlaps with the TPR2A domain (previously shown to be critical for Hop-Hsp90 interactions). Hop is phosphorylated in vitro by two cell cycle kinases, namely, casein kinase II (CKII) at S189 and cdc2-kinase at T198; both residues are found upstream of the putative NLS and TPR2A domain. Mimicking phosphorylation at either phosphorylation site appeared to affect the subcellular localization of Hop. The aim of this study was to characterize Hop with respect to its phosphorylation status in vivo, as well as its subcellular localization pattern under heat stress and determine how these properties affected its interaction with Hsp90 as a co-chaperone. Dephosphorylation of proteins under normal and heat shock conditions changed the isoform composition of Hop, providing strong evidence that Hop was phosphorylated in vivo. Surface plasmon resonance (SPR) and glutatione-S-transferase (GST) co-precipitation studies showed that a cdc2-kinase phosphorylated mimic of Hop disrupted Hop-Hsp90 binding. A full length Hop-EGFP construct, as well as substitution mutants of the predicted NLS residues within the Hop-EGFP construct, were transfected into baby hamster kidney (BHK)-21 cells in order to establish the subcellular localization of Hop under heat stress and to test whether predicted residues were critical for nuclear localization of Hop. Under normal conditions, both Hop-EGFP and the NLS mutants were predominantly cytosolic, but when the cells were subjected to heat stress, Hop and its NLS-mutants were localized to both the cytosol and the nucleus. SPR and GST co-precipitation studies showed that substitution of the residues within the major arm of the putative NLS abrogated Hop-Hsp90 interactions. The data obtained from this study, showed for the first time, that Hop was phosphorylated in vivo and suggested that phosphorylation of Hop by cdc2-kinase could inhibit Hop-Hsp90 interactions. Moreover, these results suggested that the subcellular localization of Hop was dependent on stress levels of the cell, particularly heat stress. We propose that the nuclear localization of Hop may be primarily regulated by stress and secondarily by cell cycle arrest. The major arm of the putative NLS did not affect the localization of Hop directly, but was shown to be critical for Hop-Hsp90 binding in vitro. The results of this study suggested that binding of Hop to Hsp90 sequestered Hop within the cytosol and that Hsp90 acted as a cytosolic retention factor for Hop. Both phosphorylation of Hop, and its subcellular localization, appeared to be intimately related to its interaction with Hsp90 as a co-chaperone.
- Full Text:
- Date Issued: 2008
Strategies to improve business success in selected industries
- Authors: Dayan, Oren
- Date: 2008
- Subjects: Success in business , Business -- Management , Customer relations -- Management
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: vital:9366 , http://hdl.handle.net/10948/938 , Success in business , Business -- Management , Customer relations -- Management
- Description: Successful economies are dependent on successful industries.The present study explores how business success could be improved in three selected industries, namely the motorcar, high-technology and food manufacturing industries. These industries are vital to growing the economy of countries. The present study made a significant contribution towords identifying a theoretical model to improve the business success of the motorcar, high technology amd the food manufacturing industries. The study showed that various combinations of product launching stategies (distribution channel development, product image, third-party agreements, pricing, e-business, and e-saving), as well as organisational variables (TQM and market culture) are important agreements to achieve increased sales growth and CRM effectiveness.
- Full Text:
- Date Issued: 2008
- Authors: Dayan, Oren
- Date: 2008
- Subjects: Success in business , Business -- Management , Customer relations -- Management
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: vital:9366 , http://hdl.handle.net/10948/938 , Success in business , Business -- Management , Customer relations -- Management
- Description: Successful economies are dependent on successful industries.The present study explores how business success could be improved in three selected industries, namely the motorcar, high-technology and food manufacturing industries. These industries are vital to growing the economy of countries. The present study made a significant contribution towords identifying a theoretical model to improve the business success of the motorcar, high technology amd the food manufacturing industries. The study showed that various combinations of product launching stategies (distribution channel development, product image, third-party agreements, pricing, e-business, and e-saving), as well as organisational variables (TQM and market culture) are important agreements to achieve increased sales growth and CRM effectiveness.
- Full Text:
- Date Issued: 2008
Towards the bioremediation of the hypertrophic Swartkops Solar Salt-works
- Authors: Difford, Mark
- Date: 2008
- Subjects: Salt industry and trade -- South Africa -- Port Elizabeth , Bioremediation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10606 , http://hdl.handle.net/10948/1506 , Salt industry and trade -- South Africa -- Port Elizabeth , Bioremediation
- Description: This thesis presents the results of three studies aimed at improving brine-quality at the Swartkops solar salt-works (Swartkops Sea Salt [Pty] Ltd) on the outskirts of Port Elizabeth, South Africa. This is a highly eutrophic salt-works, the management of which has become increasingly difficult in recent years. The fundamental problem is how best to operate the system at maximum capacity while limiting nutrient inputs from the nutrient-rich microtidal Swartkops Estuary. In the first study, brine-quality at several sites along the axis of the Swartkops Estuary, and the extent to which it is affected by a variety of factors, is compared. Sites were sampled on micro- and macrotidal time scales, and were selected by the management of the salt-works as possible locations for a new pump-house (for extracting brine from the estuary) for their salt-work operations at Swartkops and Missionvale. The study showed that there are incremental benefits to be had from moving the site of extraction downstream from its present position to a site closer to the mouth of the estuary, where the concentration of nutrients usually is lower and where salinity usually is higher. There is little to be gained from moving the site of extraction laterally, to the mouth of the Inlet from which brine currently is extracted, so that brine is extracted directly from the estuary itself. A set of models relating the concentrations of NH+ 4 , NO{u100000}3 , and PO34{u100000} to salinity is proposed. These take into account the influences of site and season and may be used to estimate the concentration of these nutrients from a measurement of salinity. The model for PO34{u100000} shows that it would be more damaging to the salt-works’ operations to pump “low”-salinity brine during the early months of summer than during autumn. Evidence is also presented to show that Wylde Bridge has no influence on nutrient concentrations in the estuary, with tidal flushing generally passing beyond the Wylde-Bridge break-point. The exceptionally heavy flooding of the estuary that occurred in September 2002 may, however, have biased this conclusion, because of its scouring effect. The second study concentrated on monitoring the effect of (1) decreasing pond depth and (2) increasing pond salinity—two readily available management tools—on brine quality at the salt-works. Pond depth throughout the salt-works was decreased by 40 cm, and the salinity of Pond 5, a pond in the middle of the system, was increased to 175 S. Both measures were kept in place for the duration of the study (Nov. 2002–Aug. 2004). The pond-depth experiment did not have the expected result, there being no evidence of the increase in microalgal growth in the water column that was predicted based on previous research. There was, however, a significant increase in benthic chlorophyll-a, and there was a general improvement in the condition of the sedimentary system of the salt-works. There was also a substantial decrease in particulate organic matter in the water column, with clear evidence that the remaining fraction was closely associated with living forms of particulate matter rather than with detritus. The pond-salinity experiment proves that there is a flourishing, and resilient, population of brine shrimp (Artemia salina L.) at the salt-works. Restocking the salina, or stocking it with a different strain of brine shrimp, is therefore not necessary. The results of this study show that the brine shrimp population at the salt-works needs salinities of greater than about 65–70 S to survive. As a living force they almost certainly need a protective salinity that is greater than about 120–140 S, perhaps even as great as 160 S. Brine shrimp thrived in the high salinity milieu of the experimental pond for the duration of the study, but dwindled from three other ponds of the system once their salinities fell to below 90 S, eventually to disappear from them, apparently completely, once salinity fell to below 65 S. The third and final study concentrated on establishing whether the products released by decomposing barley straw could be used in a solar salt-works to control macroalgal blooms without detrimentally affecting the benthic-mat. Previous research has shown that these products are effective inhibitors of macroalgal growth and that they remain effective under saline conditions. The results presented here show that the same products, or products released under similar conditions of decomposition, adversely effect both the structure and the function of the mat. Consequently, their use in a solar salt-works cannot be recommended.
- Full Text:
- Date Issued: 2008
- Authors: Difford, Mark
- Date: 2008
- Subjects: Salt industry and trade -- South Africa -- Port Elizabeth , Bioremediation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10606 , http://hdl.handle.net/10948/1506 , Salt industry and trade -- South Africa -- Port Elizabeth , Bioremediation
- Description: This thesis presents the results of three studies aimed at improving brine-quality at the Swartkops solar salt-works (Swartkops Sea Salt [Pty] Ltd) on the outskirts of Port Elizabeth, South Africa. This is a highly eutrophic salt-works, the management of which has become increasingly difficult in recent years. The fundamental problem is how best to operate the system at maximum capacity while limiting nutrient inputs from the nutrient-rich microtidal Swartkops Estuary. In the first study, brine-quality at several sites along the axis of the Swartkops Estuary, and the extent to which it is affected by a variety of factors, is compared. Sites were sampled on micro- and macrotidal time scales, and were selected by the management of the salt-works as possible locations for a new pump-house (for extracting brine from the estuary) for their salt-work operations at Swartkops and Missionvale. The study showed that there are incremental benefits to be had from moving the site of extraction downstream from its present position to a site closer to the mouth of the estuary, where the concentration of nutrients usually is lower and where salinity usually is higher. There is little to be gained from moving the site of extraction laterally, to the mouth of the Inlet from which brine currently is extracted, so that brine is extracted directly from the estuary itself. A set of models relating the concentrations of NH+ 4 , NO{u100000}3 , and PO34{u100000} to salinity is proposed. These take into account the influences of site and season and may be used to estimate the concentration of these nutrients from a measurement of salinity. The model for PO34{u100000} shows that it would be more damaging to the salt-works’ operations to pump “low”-salinity brine during the early months of summer than during autumn. Evidence is also presented to show that Wylde Bridge has no influence on nutrient concentrations in the estuary, with tidal flushing generally passing beyond the Wylde-Bridge break-point. The exceptionally heavy flooding of the estuary that occurred in September 2002 may, however, have biased this conclusion, because of its scouring effect. The second study concentrated on monitoring the effect of (1) decreasing pond depth and (2) increasing pond salinity—two readily available management tools—on brine quality at the salt-works. Pond depth throughout the salt-works was decreased by 40 cm, and the salinity of Pond 5, a pond in the middle of the system, was increased to 175 S. Both measures were kept in place for the duration of the study (Nov. 2002–Aug. 2004). The pond-depth experiment did not have the expected result, there being no evidence of the increase in microalgal growth in the water column that was predicted based on previous research. There was, however, a significant increase in benthic chlorophyll-a, and there was a general improvement in the condition of the sedimentary system of the salt-works. There was also a substantial decrease in particulate organic matter in the water column, with clear evidence that the remaining fraction was closely associated with living forms of particulate matter rather than with detritus. The pond-salinity experiment proves that there is a flourishing, and resilient, population of brine shrimp (Artemia salina L.) at the salt-works. Restocking the salina, or stocking it with a different strain of brine shrimp, is therefore not necessary. The results of this study show that the brine shrimp population at the salt-works needs salinities of greater than about 65–70 S to survive. As a living force they almost certainly need a protective salinity that is greater than about 120–140 S, perhaps even as great as 160 S. Brine shrimp thrived in the high salinity milieu of the experimental pond for the duration of the study, but dwindled from three other ponds of the system once their salinities fell to below 90 S, eventually to disappear from them, apparently completely, once salinity fell to below 65 S. The third and final study concentrated on establishing whether the products released by decomposing barley straw could be used in a solar salt-works to control macroalgal blooms without detrimentally affecting the benthic-mat. Previous research has shown that these products are effective inhibitors of macroalgal growth and that they remain effective under saline conditions. The results presented here show that the same products, or products released under similar conditions of decomposition, adversely effect both the structure and the function of the mat. Consequently, their use in a solar salt-works cannot be recommended.
- Full Text:
- Date Issued: 2008
A critical ethnography of HIV-positive women attending public health care facilities in Gauteng
- Authors: Du Plessis, Gretchen Erika
- Date: 2008
- Subjects: HIV-positive women -- South Africa -- Gauteng , HIV-positive women -- Social aspects -- South Africa -- Gauteng
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:16129 , http://hdl.handle.net/10948/777 , HIV-positive women -- South Africa -- Gauteng , HIV-positive women -- Social aspects -- South Africa -- Gauteng
- Description: Women living with HIV have a variety of reproductive health and psychosocial needs. The purpose of this critical ethnographic study was to examine how HIV, empowerment and reproduction are experienced by a volunteer sample of HIVpositive women attending public health care facilities in Gauteng. Feminist and critical approaches were used to guide the methodology of the research and the interpretation of the findings. Data were collected through in-depth interviews and observation. An overview of literature pertaining to the social construction of HIV-AIDS, women’s empowerment and reproductive decision-making is presented. A discourse of “healthy lifestyle” as technologies of the self is considered. Women’s empowerment as an ideal is described and structural barriers to its achievement are discussed. Stigma and discrimination as products of hegemony are discussed as important issues in the disempowerment of women living with HIV. HIV-AIDS as illness experience is reviewed with reference to the social context and to the individual context. Reproductive decision-making models and theories are critically analysed for their applicability to women living with HIV. The need for a conceptual shift in the notion of empowerment in order to understand constrained decision-making for women living with HIV is propagated. The stories of women living with HIV and dependent on public health care services are presented. Through the principles of a critical ethnography the lived experiences of these women are described by means of emerging themes. A historiography of family planning and HIV-AIDS services throws the narrations of the research participants into broader historic relief. Findings revealed that biomedical hegemonic power contoured and marked the lived experiences of women following an HIV-positive diagnosis. Taken-for-granted views of passivity and of own responsibilities regarding reproductive health are challenged. The women in the study were dependent upon public health care personnel for treatment, testing, dietary advice/supplementation and recommendations for a social xii disability grant. ARV-treatment was regarded as a low point in the illness career. All of the participants reported that the overriding problems in their lives were having too few material resources and not having the means to change this. This made them vulnerable to compounded health problems and decreased their ability to voice their own opinions about treatment. They did not regard themselves as having been at risk for contracting HIV and some harboured resentment towards men who were seen as being absolved from testing and responsibilities towards female partners, born and unborn children. Women who were not tested as part of antenatal sentinel groups tended to suffer symptoms of ill health for some time prior to being tested for HIV. Social support systems were either absent or consisted of trusted family members and friends. In many cases, women became the silent care-givers for those affected and infected by HIV. Anticipated stigma permeated the participants’ narrations of living with HIV and disclosure of their statuses was difficult. The use of male condoms, stressed during counselling sessions, was narrated as a difficult burden for women to bear. Although the research participants expressed low fertility preferences, HIV-AIDS was seen as disrupting the link between heterosexual conjugal relations and the taken-for-grantedness of procreation. HIV-AIDS also disrupted norms in infant feeding practices and bottle-feeding was regarded as a sign of possible HIV-infection and hidden. The research participants were not empowered with knowledge about how to deal with side-effects, condom failures and the reluctance of male partners to be tested for HIV. They enacted, resisted and lived with HIV in different ways, incorporating some of the biomedically prescribed posturing as women living positively and blending it with stigma-negating performances and gender-prescribed ways of dressing, walking and acting. Participation in a support group validated their experiences and promoted positive self-perception. The formation of a collective voice in the support group was hampered by irregular attendance, the interference of community leaders and horizontal violence. Power relations, yielded by biomedical hegemony, androcentric sociocultural practices, material deprivation, fear, discrimination and stigma potentially undermined the women’s abilities to become empowered. Expansion of choices in various spheres or fields and collective action xiii are proposed as dimensions to be added to an empowerment-of-women approach to the problems of reproductive health in the age of HIV-AIDS. The contribution of the study as an emancipatory project is evaluated and implications for policy and practice are suggested. On a methodological level, this study is a demonstration of the contribution to be made by a micro-level, critical analysis to the body of knowledge about female reproductive health in the era of HIV-AIDS in South Africa. On a theoretical level, this study contributes to a wider conceptualisation of women’s empowerment by recognising the interplay between micro-level elements of situated experience, knowledge and preferences and the macro-level elements of sociocultural, biomedical and material influences on health and reproductive behavior.
- Full Text:
- Date Issued: 2008
- Authors: Du Plessis, Gretchen Erika
- Date: 2008
- Subjects: HIV-positive women -- South Africa -- Gauteng , HIV-positive women -- Social aspects -- South Africa -- Gauteng
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:16129 , http://hdl.handle.net/10948/777 , HIV-positive women -- South Africa -- Gauteng , HIV-positive women -- Social aspects -- South Africa -- Gauteng
- Description: Women living with HIV have a variety of reproductive health and psychosocial needs. The purpose of this critical ethnographic study was to examine how HIV, empowerment and reproduction are experienced by a volunteer sample of HIVpositive women attending public health care facilities in Gauteng. Feminist and critical approaches were used to guide the methodology of the research and the interpretation of the findings. Data were collected through in-depth interviews and observation. An overview of literature pertaining to the social construction of HIV-AIDS, women’s empowerment and reproductive decision-making is presented. A discourse of “healthy lifestyle” as technologies of the self is considered. Women’s empowerment as an ideal is described and structural barriers to its achievement are discussed. Stigma and discrimination as products of hegemony are discussed as important issues in the disempowerment of women living with HIV. HIV-AIDS as illness experience is reviewed with reference to the social context and to the individual context. Reproductive decision-making models and theories are critically analysed for their applicability to women living with HIV. The need for a conceptual shift in the notion of empowerment in order to understand constrained decision-making for women living with HIV is propagated. The stories of women living with HIV and dependent on public health care services are presented. Through the principles of a critical ethnography the lived experiences of these women are described by means of emerging themes. A historiography of family planning and HIV-AIDS services throws the narrations of the research participants into broader historic relief. Findings revealed that biomedical hegemonic power contoured and marked the lived experiences of women following an HIV-positive diagnosis. Taken-for-granted views of passivity and of own responsibilities regarding reproductive health are challenged. The women in the study were dependent upon public health care personnel for treatment, testing, dietary advice/supplementation and recommendations for a social xii disability grant. ARV-treatment was regarded as a low point in the illness career. All of the participants reported that the overriding problems in their lives were having too few material resources and not having the means to change this. This made them vulnerable to compounded health problems and decreased their ability to voice their own opinions about treatment. They did not regard themselves as having been at risk for contracting HIV and some harboured resentment towards men who were seen as being absolved from testing and responsibilities towards female partners, born and unborn children. Women who were not tested as part of antenatal sentinel groups tended to suffer symptoms of ill health for some time prior to being tested for HIV. Social support systems were either absent or consisted of trusted family members and friends. In many cases, women became the silent care-givers for those affected and infected by HIV. Anticipated stigma permeated the participants’ narrations of living with HIV and disclosure of their statuses was difficult. The use of male condoms, stressed during counselling sessions, was narrated as a difficult burden for women to bear. Although the research participants expressed low fertility preferences, HIV-AIDS was seen as disrupting the link between heterosexual conjugal relations and the taken-for-grantedness of procreation. HIV-AIDS also disrupted norms in infant feeding practices and bottle-feeding was regarded as a sign of possible HIV-infection and hidden. The research participants were not empowered with knowledge about how to deal with side-effects, condom failures and the reluctance of male partners to be tested for HIV. They enacted, resisted and lived with HIV in different ways, incorporating some of the biomedically prescribed posturing as women living positively and blending it with stigma-negating performances and gender-prescribed ways of dressing, walking and acting. Participation in a support group validated their experiences and promoted positive self-perception. The formation of a collective voice in the support group was hampered by irregular attendance, the interference of community leaders and horizontal violence. Power relations, yielded by biomedical hegemony, androcentric sociocultural practices, material deprivation, fear, discrimination and stigma potentially undermined the women’s abilities to become empowered. Expansion of choices in various spheres or fields and collective action xiii are proposed as dimensions to be added to an empowerment-of-women approach to the problems of reproductive health in the age of HIV-AIDS. The contribution of the study as an emancipatory project is evaluated and implications for policy and practice are suggested. On a methodological level, this study is a demonstration of the contribution to be made by a micro-level, critical analysis to the body of knowledge about female reproductive health in the era of HIV-AIDS in South Africa. On a theoretical level, this study contributes to a wider conceptualisation of women’s empowerment by recognising the interplay between micro-level elements of situated experience, knowledge and preferences and the macro-level elements of sociocultural, biomedical and material influences on health and reproductive behavior.
- Full Text:
- Date Issued: 2008
The solvent-free approach versus the use of ionic liquids in the synthesis of ferrocenes
- Authors: Elago, Elago R T
- Date: 2008
- Subjects: Ferrocene , Inorganic compounds -- Synthesis , Ionic solutions , Solvents
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10396 , http://hdl.handle.net/10948/853 , Ferrocene , Inorganic compounds -- Synthesis , Ionic solutions , Solvents
- Description: The philosophy of green chemistry has seen much development in the past decade. The use of environmentally benign solvents is amongst the areas of green chemistry that have received the most attention. In this context, imidazolium ionic liquids have been widely reported to offer high product yields, fast reaction rates, excellent selectivity and generally mild working conditions, when used as reaction media. In addition, concerns about costs of solvents and the long-term environmental impact that can potentially result when solvents are discarded after their use have led to focused investigations into solvent-free procedures, as reported in recent literature. We have set out to explore the extent to which these advantages could be realized within our research. Non-volatile, non-flammable imidazolium ionic liquids [bmim][I], [bmim][BF4] and [bmim][PF6] were used as green solvents in ferrocene chemistry. Ferrocenoate esters were synthesised efficiently by the respective DCC/DMAP-promoted reactions of ferrocenecarboxylic acid and substituted benzoic acids or, alternatively, the DMAP-promoted reactions of ferrocenoyl fluoride with a range of substituted phenols in [bmim][BF4] and [bmim][PF6]. High yields and short reaction times were achieved. In addition, the ionic liquid was reused several times without a reduction in product yields. Under solvent-free conditions, DCC/DMAP-promoted reactions provided high yields within 3 min of reaction. The possible rearrangement of one of the intermediates in these reactions was modelled theoretically using density function theory (DFT) at the B3LYP/6-31G* level of approximation. Catalyst-free esterification was achieved by the application of microwave radiation to the reaction of ferrocenoyl fluoride and a range of substituted phenols. All the reactions were complete after 1 min of irradiation and products were isolated in high yield. DPAT, HfCl4, Sc(OTf)3 and Al(OTf)3 were screened as catalysts for esterification in [bmim][BF4] and under solvent-free conditions at various temperatures. All attempts at esterification of ferrocenecarboxylic acid with alcohols and phenols were unsuccessful. The Suzuki cross-coupling reaction was carried out in [bmim][BF4]. The isolated yields are, however, poor and suffer from poor reproducibility with different batches of [bmim][BF4] used.
- Full Text:
- Date Issued: 2008
- Authors: Elago, Elago R T
- Date: 2008
- Subjects: Ferrocene , Inorganic compounds -- Synthesis , Ionic solutions , Solvents
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10396 , http://hdl.handle.net/10948/853 , Ferrocene , Inorganic compounds -- Synthesis , Ionic solutions , Solvents
- Description: The philosophy of green chemistry has seen much development in the past decade. The use of environmentally benign solvents is amongst the areas of green chemistry that have received the most attention. In this context, imidazolium ionic liquids have been widely reported to offer high product yields, fast reaction rates, excellent selectivity and generally mild working conditions, when used as reaction media. In addition, concerns about costs of solvents and the long-term environmental impact that can potentially result when solvents are discarded after their use have led to focused investigations into solvent-free procedures, as reported in recent literature. We have set out to explore the extent to which these advantages could be realized within our research. Non-volatile, non-flammable imidazolium ionic liquids [bmim][I], [bmim][BF4] and [bmim][PF6] were used as green solvents in ferrocene chemistry. Ferrocenoate esters were synthesised efficiently by the respective DCC/DMAP-promoted reactions of ferrocenecarboxylic acid and substituted benzoic acids or, alternatively, the DMAP-promoted reactions of ferrocenoyl fluoride with a range of substituted phenols in [bmim][BF4] and [bmim][PF6]. High yields and short reaction times were achieved. In addition, the ionic liquid was reused several times without a reduction in product yields. Under solvent-free conditions, DCC/DMAP-promoted reactions provided high yields within 3 min of reaction. The possible rearrangement of one of the intermediates in these reactions was modelled theoretically using density function theory (DFT) at the B3LYP/6-31G* level of approximation. Catalyst-free esterification was achieved by the application of microwave radiation to the reaction of ferrocenoyl fluoride and a range of substituted phenols. All the reactions were complete after 1 min of irradiation and products were isolated in high yield. DPAT, HfCl4, Sc(OTf)3 and Al(OTf)3 were screened as catalysts for esterification in [bmim][BF4] and under solvent-free conditions at various temperatures. All attempts at esterification of ferrocenecarboxylic acid with alcohols and phenols were unsuccessful. The Suzuki cross-coupling reaction was carried out in [bmim][BF4]. The isolated yields are, however, poor and suffer from poor reproducibility with different batches of [bmim][BF4] used.
- Full Text:
- Date Issued: 2008
Decentralisation and development: the contradictions of local government in Uganda with specific reference to Masindi and Sembabule districts
- Authors: Galiwango, Wasswa Hassan
- Date: 2008
- Subjects: Decentralization in government -- Uganda , Local government -- Uganda , Uganda -- Politics and government
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8238 , http://hdl.handle.net/10948/780 , Decentralization in government -- Uganda , Local government -- Uganda , Uganda -- Politics and government
- Description: Decentralisation is the process through which Central Government transfers authority and functions to sub-national units of the Government and it traces its origin in Uganda from the “ bush” period (1981 – 1986) when Resistance Committees were established by the NRM/A in the Luwero triangle. The Mamdani Commission Report of 1987 on the Local Government system in Uganda recommended devolution of powers. Subsequently, decentralisation was launched in 1992, constitutionalised by the 1995 Constitution, and operationalised by the Local Governments Act (LGA) in 1997. Among the services devolved were education and health, which this study used as case studies to illustrate whether decentralisation has enhanced development in Uganda during the period 1993 – 2006. The study used both primary and secondary data in analysing the linkage between decentralisation and development in the two selected districts in Uganda, namely Masindi and Sembabule. Primary data was collected through interviews, questionnaires and focus group discussions while secondary data was gathered through a literature survey of relevant textbooks, newspapers, reports, legislation and journals. The findings of the study established that if decentralisation is properly planned and implemented it can make a meaningful contribution to enhancing development. However, since decentralisation is a process and not a once-off project, it evolves from one stage to another and, as it does so, it also unfolds new challenges and contradictions that need to be effectively addressed. These challenges include aspects relating to the legal framework, as well as political, fiscal and administrative decentralisation. The study recommended mitigation measures to enhance the efficiency, effectiveness, accountability, transparency, and subsequently the quality of services delivered (development) under decentralised local governance in Uganda.
- Full Text:
- Date Issued: 2008
- Authors: Galiwango, Wasswa Hassan
- Date: 2008
- Subjects: Decentralization in government -- Uganda , Local government -- Uganda , Uganda -- Politics and government
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8238 , http://hdl.handle.net/10948/780 , Decentralization in government -- Uganda , Local government -- Uganda , Uganda -- Politics and government
- Description: Decentralisation is the process through which Central Government transfers authority and functions to sub-national units of the Government and it traces its origin in Uganda from the “ bush” period (1981 – 1986) when Resistance Committees were established by the NRM/A in the Luwero triangle. The Mamdani Commission Report of 1987 on the Local Government system in Uganda recommended devolution of powers. Subsequently, decentralisation was launched in 1992, constitutionalised by the 1995 Constitution, and operationalised by the Local Governments Act (LGA) in 1997. Among the services devolved were education and health, which this study used as case studies to illustrate whether decentralisation has enhanced development in Uganda during the period 1993 – 2006. The study used both primary and secondary data in analysing the linkage between decentralisation and development in the two selected districts in Uganda, namely Masindi and Sembabule. Primary data was collected through interviews, questionnaires and focus group discussions while secondary data was gathered through a literature survey of relevant textbooks, newspapers, reports, legislation and journals. The findings of the study established that if decentralisation is properly planned and implemented it can make a meaningful contribution to enhancing development. However, since decentralisation is a process and not a once-off project, it evolves from one stage to another and, as it does so, it also unfolds new challenges and contradictions that need to be effectively addressed. These challenges include aspects relating to the legal framework, as well as political, fiscal and administrative decentralisation. The study recommended mitigation measures to enhance the efficiency, effectiveness, accountability, transparency, and subsequently the quality of services delivered (development) under decentralised local governance in Uganda.
- Full Text:
- Date Issued: 2008
Phytoplankton chlorophyll a concentration and community structure in two temporarily open/closed estuaries in the Eastern Cape, South Africa
- Authors: Gama, Phumelele Thuthuka
- Date: 2008
- Subjects: Estuarine ecology -- South Africa , Chlorophyll -- South Africa , Estuaries -- South Africa , Phytoplankton populations -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10621 , http://hdl.handle.net/10948/707 , Estuarine ecology -- South Africa , Chlorophyll -- South Africa , Estuaries -- South Africa , Phytoplankton populations -- South Africa
- Description: River flow is important in controlling phytoplankton distribution in estuaries. Data on the effect of river inflow on phytoplankton distribution patterns in temporarily open/closed estuaries is lacking. This study investigated the influence of river inflow on size-fractionated phytoplankton biomass (Chl a), community composition and environmental parameters measured monthly over three years in two temporarily open/closed estuaries in the Eastern Cape, South Africa. A once-off primary production study over an annual cycle was completed in the Van Stadens and Maitland estuaries. The study monitored physical, chemical and biological characteristics in both estuaries to examine the effects of changes in environmental factors and river inflow. Daily sampling of physico-chemical and biological variables from river to sea was carried out in the Van Stadens to investigate short-time scale effects of changes in environmental factors and river inflow on the phytoplankton biomass. Five and three stations in the main channel of the Van Stadens and Maitland estuaries respectively were sampled at 0.5 m below the water surface and 0.5 m above the sediment surface for biological and chemical variables and at the surface, 0.25 m and every 0.5 m thereafter for physical parameters. Five stations adjacent to the main channel along the estuary were monitored for groundwater macronutrient concentrations and five additional sites located within the upper catchment of the Van Stadens River were sampled on a quarterly basis over two years. Both estuaries were characterised by distinct hydrological conditions, an overwash, an open, a closed and a semi-closed mouth phase. Flooding in the Maitland and Van Stadens estuaries in 2001 and 2002 caused sediment scour, altered channel morphology and brought about breaching of the mouth. Flood driven mouth-breaching events occurred three and four times in each of the estuaries during the study. The mouth stayed open 20 – 25 percent and was closed 60 – 65 percent of the time. In the Van Stadens the closed overwash mouth condition occurred approximately 10 – 20 percent of the time while in the Maitland it occurred less with the semi-closed mouth condition occurring 10 – 20 percent of the time. Incidents related to mouth opening not associated with strong river floods occurred approximately 10 – 15 percent of the time, although in the Maitland a semi-closed mouth state persisted more frequently than in the Van Stadens Estuary. During flooding events salinity dropped to low levels (< 5 psu) but soon recovered to brackish conditions when river flow was reduced and marine water penetrated deep upstream. Reduction in river flow combined with marine sediment deposition resulted in the closure of the mouth. During closed mouth conditions strong onshore storm surges and spring high tides introduced marine water through overwash that kept salinity high. In both estuaries salinity showed a negative correlation with rainfall (R2 = 0.12), indicative of the strong influence of marine overwash that kept salinity high thus masking the influence of freshwater. High rainfall in the Van Stadens Estuary caused high levels of turbidity that reduced light penetration at depth. Light attenuation was positively correlated with the high rainfall (R 2 = 0.26) suggesting that increased turbidity was linked to rainfall induced discharge. In contrast, in the Maitland Estuary light attenuation did not show any correlation with increased rainfall possibly because of the reduced water depth and increased euphotic zone following the floods in 2002. High river inflow introduced macronutrients in both estuaries such that dissolved inorganic phosphates (DIP) and dissolved inorganic nitrogen (DIN) concentrations in the Van Stadens Estuary were strongly correlated with rainfall (R2 = 0.78 and 0.57 respectively). In the Maitland Estuary DIP and DIN concentrations remained significantly higher (p < 0.05) compared to that in the Van Stadens suggesting that the Maitland catchment contributed greater nutrient input into the estuary and may be associated with farming activities. Phytoplankton chlorophyll a (Chl a) ranged from 0.8 – 13.9 μg L-1 in the Van Stadens and in the Maitland Estuary from 5.3 – 138 μg L-1 during the 3-year study. During the open mouth condition Chl a biomass and primary production ranged from 5.4 – 52.9 μg Chl a L-1 and 1.2 – 11.7 mg C m-2 d-1 in the Maitland and in the Van Stadens from 1.6 – 9.8 μg Chl a L-1 and 1.2 - 14 mg C m-2 d-1 respectively. Maximum annual primary production in the Maitland and Van Stadens estuaries was 8.8 and 5.1 g C m-2 y-1 respectively. When the mouth was open in the Van Stadens Estuary the microphytoplankton (> 20 μm) accounted for > 65 percent of the Chl a, whereas during closed mouth conditions they accounted for about 55 percent of the Chl a biomass. Chlorophytes became the dominant taxon in the dry summer months but were replaced by cryptophytes and dinoflagellates during the wet season. When nutrient concentrations were low during low flow conditions in the Van Stadens Estuary mixotrophic microphytoplankton became an important fraction of the water column together with phototrophic dinoflagellates and cryptophytes. In the Maitland large sized chlorophytes were the dominant taxa in late spring and summer seasons and made up more than 80 percent of the cell numbers. In the Maitland before the floods in 2002 cyanophytes were the dominant group in late spring contributing more than 75 percent in cell abundance. Data from the short-term study in the Van Stadens Estuary showed similarities and differences in the Chl a response to increased river inflow. High river inflow initially reduced Chl a biomass followed by a recovery period of a couple of days compared to a 8 – 10 week recovery period in studies monitored over seasonal and annual temporal scales. The responses may be dissimilar but help to illustrate that there are similar response patterns to environmental forcing necessary to support phytoplankton biomass at different temporal scales. This study has demonstrated that flooding events caused by strong river flow cause breaching of the mouth, a reduction in salinity and marked nutrient input. Although the causes of flooding can be similar in both estuaries the resultant effects are varied and can alter the ability of the estuary to retain water. This study was able to demonstrate that the supply of macronutrients from the catchment was strongly correlated with rainfall (R2 = 0.67) and that phytoplankton growth mainly depended on an allochthonous source of macronutrients although internal supplies could be critical at times in controlling microalgal biomass.
- Full Text:
- Date Issued: 2008
- Authors: Gama, Phumelele Thuthuka
- Date: 2008
- Subjects: Estuarine ecology -- South Africa , Chlorophyll -- South Africa , Estuaries -- South Africa , Phytoplankton populations -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10621 , http://hdl.handle.net/10948/707 , Estuarine ecology -- South Africa , Chlorophyll -- South Africa , Estuaries -- South Africa , Phytoplankton populations -- South Africa
- Description: River flow is important in controlling phytoplankton distribution in estuaries. Data on the effect of river inflow on phytoplankton distribution patterns in temporarily open/closed estuaries is lacking. This study investigated the influence of river inflow on size-fractionated phytoplankton biomass (Chl a), community composition and environmental parameters measured monthly over three years in two temporarily open/closed estuaries in the Eastern Cape, South Africa. A once-off primary production study over an annual cycle was completed in the Van Stadens and Maitland estuaries. The study monitored physical, chemical and biological characteristics in both estuaries to examine the effects of changes in environmental factors and river inflow. Daily sampling of physico-chemical and biological variables from river to sea was carried out in the Van Stadens to investigate short-time scale effects of changes in environmental factors and river inflow on the phytoplankton biomass. Five and three stations in the main channel of the Van Stadens and Maitland estuaries respectively were sampled at 0.5 m below the water surface and 0.5 m above the sediment surface for biological and chemical variables and at the surface, 0.25 m and every 0.5 m thereafter for physical parameters. Five stations adjacent to the main channel along the estuary were monitored for groundwater macronutrient concentrations and five additional sites located within the upper catchment of the Van Stadens River were sampled on a quarterly basis over two years. Both estuaries were characterised by distinct hydrological conditions, an overwash, an open, a closed and a semi-closed mouth phase. Flooding in the Maitland and Van Stadens estuaries in 2001 and 2002 caused sediment scour, altered channel morphology and brought about breaching of the mouth. Flood driven mouth-breaching events occurred three and four times in each of the estuaries during the study. The mouth stayed open 20 – 25 percent and was closed 60 – 65 percent of the time. In the Van Stadens the closed overwash mouth condition occurred approximately 10 – 20 percent of the time while in the Maitland it occurred less with the semi-closed mouth condition occurring 10 – 20 percent of the time. Incidents related to mouth opening not associated with strong river floods occurred approximately 10 – 15 percent of the time, although in the Maitland a semi-closed mouth state persisted more frequently than in the Van Stadens Estuary. During flooding events salinity dropped to low levels (< 5 psu) but soon recovered to brackish conditions when river flow was reduced and marine water penetrated deep upstream. Reduction in river flow combined with marine sediment deposition resulted in the closure of the mouth. During closed mouth conditions strong onshore storm surges and spring high tides introduced marine water through overwash that kept salinity high. In both estuaries salinity showed a negative correlation with rainfall (R2 = 0.12), indicative of the strong influence of marine overwash that kept salinity high thus masking the influence of freshwater. High rainfall in the Van Stadens Estuary caused high levels of turbidity that reduced light penetration at depth. Light attenuation was positively correlated with the high rainfall (R 2 = 0.26) suggesting that increased turbidity was linked to rainfall induced discharge. In contrast, in the Maitland Estuary light attenuation did not show any correlation with increased rainfall possibly because of the reduced water depth and increased euphotic zone following the floods in 2002. High river inflow introduced macronutrients in both estuaries such that dissolved inorganic phosphates (DIP) and dissolved inorganic nitrogen (DIN) concentrations in the Van Stadens Estuary were strongly correlated with rainfall (R2 = 0.78 and 0.57 respectively). In the Maitland Estuary DIP and DIN concentrations remained significantly higher (p < 0.05) compared to that in the Van Stadens suggesting that the Maitland catchment contributed greater nutrient input into the estuary and may be associated with farming activities. Phytoplankton chlorophyll a (Chl a) ranged from 0.8 – 13.9 μg L-1 in the Van Stadens and in the Maitland Estuary from 5.3 – 138 μg L-1 during the 3-year study. During the open mouth condition Chl a biomass and primary production ranged from 5.4 – 52.9 μg Chl a L-1 and 1.2 – 11.7 mg C m-2 d-1 in the Maitland and in the Van Stadens from 1.6 – 9.8 μg Chl a L-1 and 1.2 - 14 mg C m-2 d-1 respectively. Maximum annual primary production in the Maitland and Van Stadens estuaries was 8.8 and 5.1 g C m-2 y-1 respectively. When the mouth was open in the Van Stadens Estuary the microphytoplankton (> 20 μm) accounted for > 65 percent of the Chl a, whereas during closed mouth conditions they accounted for about 55 percent of the Chl a biomass. Chlorophytes became the dominant taxon in the dry summer months but were replaced by cryptophytes and dinoflagellates during the wet season. When nutrient concentrations were low during low flow conditions in the Van Stadens Estuary mixotrophic microphytoplankton became an important fraction of the water column together with phototrophic dinoflagellates and cryptophytes. In the Maitland large sized chlorophytes were the dominant taxa in late spring and summer seasons and made up more than 80 percent of the cell numbers. In the Maitland before the floods in 2002 cyanophytes were the dominant group in late spring contributing more than 75 percent in cell abundance. Data from the short-term study in the Van Stadens Estuary showed similarities and differences in the Chl a response to increased river inflow. High river inflow initially reduced Chl a biomass followed by a recovery period of a couple of days compared to a 8 – 10 week recovery period in studies monitored over seasonal and annual temporal scales. The responses may be dissimilar but help to illustrate that there are similar response patterns to environmental forcing necessary to support phytoplankton biomass at different temporal scales. This study has demonstrated that flooding events caused by strong river flow cause breaching of the mouth, a reduction in salinity and marked nutrient input. Although the causes of flooding can be similar in both estuaries the resultant effects are varied and can alter the ability of the estuary to retain water. This study was able to demonstrate that the supply of macronutrients from the catchment was strongly correlated with rainfall (R2 = 0.67) and that phytoplankton growth mainly depended on an allochthonous source of macronutrients although internal supplies could be critical at times in controlling microalgal biomass.
- Full Text:
- Date Issued: 2008
A model to improve the effectiveness of the Occupational Health and Safety Inspectorate function relative to South African construction
- Authors: Geminiani, Franco Luciano
- Date: 2008
- Subjects: Construction industry -- Safety measures
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9695 , http://hdl.handle.net/10948/719 , Construction industry -- Safety measures
- Description: Irrespective of all the efforts made by the Department of Labour (DoL) and other relevant stakeholders to improve the performance of Occupational Health and Safety (OH&S) in construction. In the Construction Industry, there is still a very high level of accidents and fatalities in South Africa. Injuries and accidents to workers do not help a community in any nation. The construction industry in South Africa is generally known to be one of the most hazardous and has one of the most dismal OH&S records among all industrial segments with an unacceptably high level of injuries and fatalities resulting in considerable human suffering. A doctoral study was recently conducted with the aim of investigating the effectiveness and performance of the DoL OH&S Inspectorate in South Africa. The empirical study was conducted among a range of stakeholders: civil engineering and building contractors; OH&S consultants; project managers; DoL inspectors; and designers by means of a questionnaire survey. The methodology adopted in this study included the exploratory and descriptive methods, which entails the technique of observation including the use of questionnaires and data analysis. The salient findings of the study are presented and elucidate that the DoL OH&S Inspectorate is not effective in terms of OH&S relative to the construction industry in South Africa. Conclusions and recommendations included expound that the DoL OH&S Inspectorate is not effectively conducting their duties reinforcing the need for a reviewed OH&S Inspectorate model framework. The proposed structured normative model consists of fundamental elements which would improve the effectiveness of the DoL OH&S Inspectorate. The findings of the study with recommendations are included.
- Full Text:
- Date Issued: 2008
- Authors: Geminiani, Franco Luciano
- Date: 2008
- Subjects: Construction industry -- Safety measures
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9695 , http://hdl.handle.net/10948/719 , Construction industry -- Safety measures
- Description: Irrespective of all the efforts made by the Department of Labour (DoL) and other relevant stakeholders to improve the performance of Occupational Health and Safety (OH&S) in construction. In the Construction Industry, there is still a very high level of accidents and fatalities in South Africa. Injuries and accidents to workers do not help a community in any nation. The construction industry in South Africa is generally known to be one of the most hazardous and has one of the most dismal OH&S records among all industrial segments with an unacceptably high level of injuries and fatalities resulting in considerable human suffering. A doctoral study was recently conducted with the aim of investigating the effectiveness and performance of the DoL OH&S Inspectorate in South Africa. The empirical study was conducted among a range of stakeholders: civil engineering and building contractors; OH&S consultants; project managers; DoL inspectors; and designers by means of a questionnaire survey. The methodology adopted in this study included the exploratory and descriptive methods, which entails the technique of observation including the use of questionnaires and data analysis. The salient findings of the study are presented and elucidate that the DoL OH&S Inspectorate is not effective in terms of OH&S relative to the construction industry in South Africa. Conclusions and recommendations included expound that the DoL OH&S Inspectorate is not effectively conducting their duties reinforcing the need for a reviewed OH&S Inspectorate model framework. The proposed structured normative model consists of fundamental elements which would improve the effectiveness of the DoL OH&S Inspectorate. The findings of the study with recommendations are included.
- Full Text:
- Date Issued: 2008
Towards understanding the mechanism of dimerisation of Saccharomyces cerevisiae eukaryotic translation initiation factor 5A
- Authors: Gentz, Petra Monika
- Date: 2008
- Subjects: Cytology Molecular biology Biochemistry Proteins -- Analysis Proteomics Polypeptides Amino acids -- Synthesis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3992 , http://hdl.handle.net/10962/d1004052
- Description: Eukaryotic translation initiation factor 5A (eIF5A) is the only known protein to contain hypusine, formed by post-translational modification of a highly conserved lysine residue. Hypusination is essential for eIF5A function, being required for binding of a specific subset of mRNAs necessary for progression of eukaryotic cells through the G1-S checkpoint. Little structural information is available for eIF5A other than that derived from archaeal homologues. The aim of this study was to conduct structure-function studies on Saccharomyces cerevisiae (yeast) eIF5A, encoded by TIF51A. Homology models of eIF5A were generated from the Methanococcus jannaschii archaeal homologue (aIF5A) and two Leishmania eIF5As. The models, along with secondary structure predictions identified an a-helix on the C-terminal domain, unique to eukaryote eIF5A. The Neurospora crassa structural analogue, HEX-1, which dimerises in three configurations, was used to generate similar dimeric model configurations of eIF5A. A biochemical and functional analysis was used to validate the homology models of eIF5A.Since the crystal structures of aIF5A and eIF5A were solved from unhypusinated protein produced in Escherichia coli, 6 x His-tagged eIF5A (His-eIF5A) was used for biochemical analysis. This analysis revealed that eIF5A existed as a dimer in solution, dependent on the presence of the highly conserved Cys 39 residue. A yeast TIF51A/TIF51B null yeast strain, with a chromosomal copy of TIF51A under control of PGAL1, was used to confirm that HiseIF5A and selected eIF5A mutants were functional in vivo. Biochemical analysis showed that hypusinated His-eIF5A also exists as a dimer, but neither the dimerisation, nor the function of eIF5A are dependent on the presence of Cys 39. Rather they depend on the presence of hypusine (Hpu) 51 and the presence of RNA leading to the conclusion that RNA and hypusine are required for dimerisation and hence function, of native eIF5A in vivo. In contrast, a Lys 51 to Arg 51 substitution or RNase treatment of His-eIF5A produced in E. coli did not destabilize the dimeric form, suggesting different folding/dimerisation mechanisms in E. coli and yeast cells. The information obtained from the initial homology models, together with the results of the biochemical analysis was used to propose a mechanism for dimerisation of yeast eIF5A involving both hypusine and RNA.
- Full Text:
- Date Issued: 2008
- Authors: Gentz, Petra Monika
- Date: 2008
- Subjects: Cytology Molecular biology Biochemistry Proteins -- Analysis Proteomics Polypeptides Amino acids -- Synthesis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3992 , http://hdl.handle.net/10962/d1004052
- Description: Eukaryotic translation initiation factor 5A (eIF5A) is the only known protein to contain hypusine, formed by post-translational modification of a highly conserved lysine residue. Hypusination is essential for eIF5A function, being required for binding of a specific subset of mRNAs necessary for progression of eukaryotic cells through the G1-S checkpoint. Little structural information is available for eIF5A other than that derived from archaeal homologues. The aim of this study was to conduct structure-function studies on Saccharomyces cerevisiae (yeast) eIF5A, encoded by TIF51A. Homology models of eIF5A were generated from the Methanococcus jannaschii archaeal homologue (aIF5A) and two Leishmania eIF5As. The models, along with secondary structure predictions identified an a-helix on the C-terminal domain, unique to eukaryote eIF5A. The Neurospora crassa structural analogue, HEX-1, which dimerises in three configurations, was used to generate similar dimeric model configurations of eIF5A. A biochemical and functional analysis was used to validate the homology models of eIF5A.Since the crystal structures of aIF5A and eIF5A were solved from unhypusinated protein produced in Escherichia coli, 6 x His-tagged eIF5A (His-eIF5A) was used for biochemical analysis. This analysis revealed that eIF5A existed as a dimer in solution, dependent on the presence of the highly conserved Cys 39 residue. A yeast TIF51A/TIF51B null yeast strain, with a chromosomal copy of TIF51A under control of PGAL1, was used to confirm that HiseIF5A and selected eIF5A mutants were functional in vivo. Biochemical analysis showed that hypusinated His-eIF5A also exists as a dimer, but neither the dimerisation, nor the function of eIF5A are dependent on the presence of Cys 39. Rather they depend on the presence of hypusine (Hpu) 51 and the presence of RNA leading to the conclusion that RNA and hypusine are required for dimerisation and hence function, of native eIF5A in vivo. In contrast, a Lys 51 to Arg 51 substitution or RNase treatment of His-eIF5A produced in E. coli did not destabilize the dimeric form, suggesting different folding/dimerisation mechanisms in E. coli and yeast cells. The information obtained from the initial homology models, together with the results of the biochemical analysis was used to propose a mechanism for dimerisation of yeast eIF5A involving both hypusine and RNA.
- Full Text:
- Date Issued: 2008
The zonation of coastal dune plants in relation to sand burial, resource availability and physiological adaptation
- Authors: Gilbert, Matthew Edmund
- Date: 2008
- Subjects: Sand dune conservation -- South Africa -- Eastern Cape Coastal ecology -- South Africa -- Eastern Cape Botany -- South Africa -- Eastern Cape Coastal biology -- South Africa -- Eastern Cape Littoral plants -- South Africa -- Eastern Cape Littoral plants Sand dune plants -- Ecophysiology Sand dune plants -- Geographical distribution
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4195 , http://hdl.handle.net/10962/d1003764
- Description: When considering the large amount of work done on dune ecology, and that a number of the classical ecological theories originate from work on dunes, it is apparent that there remains a need for physiological and mechanistic explanations of dune plant phenomena. This thesis demonstrated that in the extreme coastal environment dune plants must survive both high rates of burial (disturbance), and low nutrient availability (stress). The ability of four species to respond to these two factors corresponded with their position in a vegetation gradient on the dunes. A low stem tissue density was shown to enhance the potential stem elongation rate of buried plants, but reduced the maximum height to which a plant could grow. Such a tradeoff implies that tall light-competitive plants are able to survive only in stable areas, while burial responsive mobile-dune plants are limited to areas of low vegetation height. This stem tissue density tradeoff was suggested as the mechanism determining the zonation that species show within the dune vegetation gradient present at various sites in South Africa. Finally, detailed investigations of dune plant ecophysiology found that: 1) The resources used in the response to burial derive from external sources of carbon and nitrogen, as well as simple physiological and physical mechanisms of resource allocation. 2) The leaves of dune plants were found to be operating at one extreme of the photosynthetic continuum; viz efficient use of leaf nitrogen at the expense of water loss. 3) Contrary to other ecosystems, the environmental characteristics of dunes may allow plants to occupy a high disturbance, high stress niche, through the maintenance of lowered competition. 4) At least two mobile-dune species form steep dunes, and are able to optimise growth, on steeper dunes, such that they have to grow less in response to burial than plants that form more shallow dunes. In this thesis, it was shown that the link between the carbon and nitrogen economies of dune plants was pivotal in determining species distributions and survival under extreme environmental conditions. As vast areas of the world’s surface are covered by sand dunes these observations are not just of passing interest.
- Full Text:
- Date Issued: 2008
- Authors: Gilbert, Matthew Edmund
- Date: 2008
- Subjects: Sand dune conservation -- South Africa -- Eastern Cape Coastal ecology -- South Africa -- Eastern Cape Botany -- South Africa -- Eastern Cape Coastal biology -- South Africa -- Eastern Cape Littoral plants -- South Africa -- Eastern Cape Littoral plants Sand dune plants -- Ecophysiology Sand dune plants -- Geographical distribution
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4195 , http://hdl.handle.net/10962/d1003764
- Description: When considering the large amount of work done on dune ecology, and that a number of the classical ecological theories originate from work on dunes, it is apparent that there remains a need for physiological and mechanistic explanations of dune plant phenomena. This thesis demonstrated that in the extreme coastal environment dune plants must survive both high rates of burial (disturbance), and low nutrient availability (stress). The ability of four species to respond to these two factors corresponded with their position in a vegetation gradient on the dunes. A low stem tissue density was shown to enhance the potential stem elongation rate of buried plants, but reduced the maximum height to which a plant could grow. Such a tradeoff implies that tall light-competitive plants are able to survive only in stable areas, while burial responsive mobile-dune plants are limited to areas of low vegetation height. This stem tissue density tradeoff was suggested as the mechanism determining the zonation that species show within the dune vegetation gradient present at various sites in South Africa. Finally, detailed investigations of dune plant ecophysiology found that: 1) The resources used in the response to burial derive from external sources of carbon and nitrogen, as well as simple physiological and physical mechanisms of resource allocation. 2) The leaves of dune plants were found to be operating at one extreme of the photosynthetic continuum; viz efficient use of leaf nitrogen at the expense of water loss. 3) Contrary to other ecosystems, the environmental characteristics of dunes may allow plants to occupy a high disturbance, high stress niche, through the maintenance of lowered competition. 4) At least two mobile-dune species form steep dunes, and are able to optimise growth, on steeper dunes, such that they have to grow less in response to burial than plants that form more shallow dunes. In this thesis, it was shown that the link between the carbon and nitrogen economies of dune plants was pivotal in determining species distributions and survival under extreme environmental conditions. As vast areas of the world’s surface are covered by sand dunes these observations are not just of passing interest.
- Full Text:
- Date Issued: 2008
"A complex and delicate web" : a comparative study of selected speculative novels by Margaret Atwood, Ursula K. Le Guin, Doris Lessing and Marge Piercy
- Authors: Glover, Jayne Ashleigh
- Date: 2008
- Subjects: Atwood, Margaret Eleanor, 1939- -- Criticism and interpretation Le Guin, Ursula K., 1929- -- Criticism and interpretation Lessing, Doris May, 1919- -- Criticism and interpretation Piercy, Marge Piercy, Marge -- Criticism and interpretation Utopias in literature Dystopias in literature Science fiction, English -- History and criticism Fantasy fiction -- History and criticism Fantasy literature -- History and criticism Women authors -- 20th Century Women authors -- 21st Century English fiction -- 20th Century English fiction -- 21st Century
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2199 , http://hdl.handle.net/10962/d1002241
- Description: This thesis examines selected speculative novels by Margaret Atwood, Ursula K. Le Guin, Doris Lessing and Marge Piercy. It argues that a specifiable ecological ethic can be traced in their work – an ethic which is explored by them through the tensions between utopian and dystopian discourses. The first part of the thesis begins by theorising the concept of an ecological ethic of respect for the Other through current ecological philosophies, such as those developed by Val Plumwood. Thereafter, it contextualises the novels within the broader field of science fiction, and speculative fiction in particular, arguing that the shift from a critical utopian to a critical dystopian style evinces their changing treatment of this ecological ethic within their work. The remainder of the thesis is divided into two parts, each providing close readings of chosen novels in the light of this argument. Part Two provides a reading of Le Guin’s early Hainish novels, The Left Hand of Darkness, The Word for World is Forest and The Dispossessed, followed by an examination of Piercy’s Woman on the Edge of Time, Lessing’s The Marriages Between Zones Three, Four and Five, and Atwood’s The Handmaid’s Tale. The third, and final, part of the thesis consists of individual chapters analysing the later speculative novels of each author. Piercy’s He, She and It, Le Guin’s The Telling, and Atwood’s Oryx and Crake are all scrutinised, as are Lessing’s two recent ‘Ifrik’ novels. This thesis shows, then, that speculative fiction is able to realise through fiction many of the ideals of ecological thinkers. Furthermore, the increasing dystopianism of these novels reflects the greater urgency with which the problem of Othering needs to be addressed in the light of the present global ecological crisis.
- Full Text:
- Date Issued: 2008
- Authors: Glover, Jayne Ashleigh
- Date: 2008
- Subjects: Atwood, Margaret Eleanor, 1939- -- Criticism and interpretation Le Guin, Ursula K., 1929- -- Criticism and interpretation Lessing, Doris May, 1919- -- Criticism and interpretation Piercy, Marge Piercy, Marge -- Criticism and interpretation Utopias in literature Dystopias in literature Science fiction, English -- History and criticism Fantasy fiction -- History and criticism Fantasy literature -- History and criticism Women authors -- 20th Century Women authors -- 21st Century English fiction -- 20th Century English fiction -- 21st Century
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2199 , http://hdl.handle.net/10962/d1002241
- Description: This thesis examines selected speculative novels by Margaret Atwood, Ursula K. Le Guin, Doris Lessing and Marge Piercy. It argues that a specifiable ecological ethic can be traced in their work – an ethic which is explored by them through the tensions between utopian and dystopian discourses. The first part of the thesis begins by theorising the concept of an ecological ethic of respect for the Other through current ecological philosophies, such as those developed by Val Plumwood. Thereafter, it contextualises the novels within the broader field of science fiction, and speculative fiction in particular, arguing that the shift from a critical utopian to a critical dystopian style evinces their changing treatment of this ecological ethic within their work. The remainder of the thesis is divided into two parts, each providing close readings of chosen novels in the light of this argument. Part Two provides a reading of Le Guin’s early Hainish novels, The Left Hand of Darkness, The Word for World is Forest and The Dispossessed, followed by an examination of Piercy’s Woman on the Edge of Time, Lessing’s The Marriages Between Zones Three, Four and Five, and Atwood’s The Handmaid’s Tale. The third, and final, part of the thesis consists of individual chapters analysing the later speculative novels of each author. Piercy’s He, She and It, Le Guin’s The Telling, and Atwood’s Oryx and Crake are all scrutinised, as are Lessing’s two recent ‘Ifrik’ novels. This thesis shows, then, that speculative fiction is able to realise through fiction many of the ideals of ecological thinkers. Furthermore, the increasing dystopianism of these novels reflects the greater urgency with which the problem of Othering needs to be addressed in the light of the present global ecological crisis.
- Full Text:
- Date Issued: 2008
A supplementary coping skills programme for parents of children diagnosed with attention deficit hyperactivity disorder
- Authors: Gomes, Ana Maria
- Date: 2008
- Subjects: Attention-deficit-disordered children -- Family relationships , Children with disabilities -- Education
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9471 , http://hdl.handle.net/10948/686
- Description: Attention Deficit Hyperactivity Disorder (ADHD)-related behaviour difficulties are said to be the cause of much of the disharmony and discord that exists within many families with ADHD-diagnosed children. On the basis of this understanding, a supplementary programme of behaviour modification, referred to as the Coping Skills Programme, was designed and implemented over a designated period of time, as a trial efficiency test, with a view to alleviate some of the family environmental stress caused by the effects of this disorder. There were three main aims to this research project, related to the research questions: Firstly, to establish to what extent this programme helped with the kinds of problems and difficulties being experienced by the parents of ADHD-diagnosed children and by the children themselves; secondly, to make recommendations regarding how to access and use such a programme and learn its skills, and thirdly to determine further ways with which to improve the Coping Skills Programme. The research design was based on Interpretive Theory and was qualitative in nature. An in-depth literature study was undertaken, which together with all the field notes acquired during the course of the study, formed the foundation of the study. A needs analysis was also carried out to ascertain the level and variety of ADHD-related needs that exist within the family unit. This needs analysis took place in the Nelson Mandela Metropole in the Eastern Cape to ascertain the level and variety of ADHD-related needs that exist within the family unit. The sampling selection of participants was both purposeful and dependent on availability, in order obtain as wide a range of information as possible, regarding specific ADHD-related criteria. This data was used as a foundation for the programme’s development. Information was gathered by means of phenomenological interviews, case study analysis, a focus group interview, field notes, observations and an audit trail. Measures were taken to ensure that the study was ethically conducted and trustworthiness maintained. The Coping Skills Programme was implemented with different families with ADHD-diagnosed children, within its designated time, which varied from family to family from between 8 and 10 weeks. Finally, three families were xx selected as case studies to substantiate the findings of this research study. Their selection was based on the range of the children’s age, the variety of their combined needs, the way in which each family dealt with the challenges posed by the programme, the parents’ involvement and the rate of success experienced by each family at the end of the allotted time. At the end of the programme’s implementation period it was found that confusion regarding parental role clarity and the role of the child in the home had a strong bearing on the treatment and management of ADHD-related difficulties. It was also found that the effect of parental unity and/or discord had a direct impact on ADHD-related behaviour. Equally important to the effective management of ADHD-related difficulties were the parental understanding and perceptions regarding their child’s ADHD-related needs and difficulties. The effectiveness of behaviour modification in relation to the level of parental involvement was also salient, as was the use of effective, positive communication to achievement of optimum results. Parental understanding of the role of discipline and how the effective use of this skill benefits the ADHD-diagnosed child became clear, as did the value of consistency in behaviour modification. The conclusion was reached that a programme as flexible as the Coping Skills Programme, when used appropriately and as a supplement to other forms of therapy, may be a significant source of assistance, support, encouragement and empowerment to families with members suffering with ADHD.
- Full Text:
- Date Issued: 2008
- Authors: Gomes, Ana Maria
- Date: 2008
- Subjects: Attention-deficit-disordered children -- Family relationships , Children with disabilities -- Education
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9471 , http://hdl.handle.net/10948/686
- Description: Attention Deficit Hyperactivity Disorder (ADHD)-related behaviour difficulties are said to be the cause of much of the disharmony and discord that exists within many families with ADHD-diagnosed children. On the basis of this understanding, a supplementary programme of behaviour modification, referred to as the Coping Skills Programme, was designed and implemented over a designated period of time, as a trial efficiency test, with a view to alleviate some of the family environmental stress caused by the effects of this disorder. There were three main aims to this research project, related to the research questions: Firstly, to establish to what extent this programme helped with the kinds of problems and difficulties being experienced by the parents of ADHD-diagnosed children and by the children themselves; secondly, to make recommendations regarding how to access and use such a programme and learn its skills, and thirdly to determine further ways with which to improve the Coping Skills Programme. The research design was based on Interpretive Theory and was qualitative in nature. An in-depth literature study was undertaken, which together with all the field notes acquired during the course of the study, formed the foundation of the study. A needs analysis was also carried out to ascertain the level and variety of ADHD-related needs that exist within the family unit. This needs analysis took place in the Nelson Mandela Metropole in the Eastern Cape to ascertain the level and variety of ADHD-related needs that exist within the family unit. The sampling selection of participants was both purposeful and dependent on availability, in order obtain as wide a range of information as possible, regarding specific ADHD-related criteria. This data was used as a foundation for the programme’s development. Information was gathered by means of phenomenological interviews, case study analysis, a focus group interview, field notes, observations and an audit trail. Measures were taken to ensure that the study was ethically conducted and trustworthiness maintained. The Coping Skills Programme was implemented with different families with ADHD-diagnosed children, within its designated time, which varied from family to family from between 8 and 10 weeks. Finally, three families were xx selected as case studies to substantiate the findings of this research study. Their selection was based on the range of the children’s age, the variety of their combined needs, the way in which each family dealt with the challenges posed by the programme, the parents’ involvement and the rate of success experienced by each family at the end of the allotted time. At the end of the programme’s implementation period it was found that confusion regarding parental role clarity and the role of the child in the home had a strong bearing on the treatment and management of ADHD-related difficulties. It was also found that the effect of parental unity and/or discord had a direct impact on ADHD-related behaviour. Equally important to the effective management of ADHD-related difficulties were the parental understanding and perceptions regarding their child’s ADHD-related needs and difficulties. The effectiveness of behaviour modification in relation to the level of parental involvement was also salient, as was the use of effective, positive communication to achievement of optimum results. Parental understanding of the role of discipline and how the effective use of this skill benefits the ADHD-diagnosed child became clear, as did the value of consistency in behaviour modification. The conclusion was reached that a programme as flexible as the Coping Skills Programme, when used appropriately and as a supplement to other forms of therapy, may be a significant source of assistance, support, encouragement and empowerment to families with members suffering with ADHD.
- Full Text:
- Date Issued: 2008