A framework to measure employee engagement at Stefanutti Stocks RPM Business Unit
- Authors: Maher, Theresa
- Date: 2021-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/53315 , vital:45142
- Description: Work gratification and expectancies are of the utmost importance to the skilled workforce in the South African construction industry. The price paid for a demotivated workforce in this industry is very high and it leads to friction in the workplace, displeasing work outcomes and time delays. Furthermore it leads to increased incidences of theft,absenteeism and outputs that arebelow standard in terms of productivityand thequality of the work.In order to motivate the workforce in the construction industry,a day-by-day, step-by-step,hands-on approachmust be used. The aforesaid aids site managers to manage effectively and this in turn leads to an increase in production by way of enhanced productivity. Research shows that a correlationbetweenmotivation, excelling at work, improved productivity and fulfilment and expectancyexist. The reason why individuals act in a specific manner and choose not to act in a certain way can be directly linked totheirmotivation and engagement.As a member ofthe construction industry in South Africa, Stefanutti Stocks isseen as one of the leading construction groups. Employing more than 12 000 workers it has the ability to provide a wide variety of different scale projects for a host of clients in varied markets. The division concentrated on in this study is the Roads, Pipelines and Mining Services (RPM)Business Unit. The MD of the RPM Business Unit when starting at the company a few years ago came to the conclusion that in order for the RPM Business Unit to function optimally certain business inconsistencies regarding employee engagement needed to be addressed. Based on this he decided to use a consulting firm, AIM,to establish what the exact concernswere and what interventions wererequired to deal with them. ivInterventions facilitatedby AIM includedManagement Training Programmes and Workshops as well as one-on-one coaching sessions with selected individuals.The methodology used in this study was to measurethe current level of employee engagement subsequent toengagement interventionsconcludedby AIM.The approach used was the use of surveys distributed through AIM in conjunction with the RPM Business Unit’sHR Department. The surveys were distributed via Survey Monkey Software owned by the RPM Business Unit of Stefanutti Stocks. , Thesis (MBA) -- Faculty of Business and Economic Sciences, NMMU Business School, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Maher, Theresa
- Date: 2021-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/53315 , vital:45142
- Description: Work gratification and expectancies are of the utmost importance to the skilled workforce in the South African construction industry. The price paid for a demotivated workforce in this industry is very high and it leads to friction in the workplace, displeasing work outcomes and time delays. Furthermore it leads to increased incidences of theft,absenteeism and outputs that arebelow standard in terms of productivityand thequality of the work.In order to motivate the workforce in the construction industry,a day-by-day, step-by-step,hands-on approachmust be used. The aforesaid aids site managers to manage effectively and this in turn leads to an increase in production by way of enhanced productivity. Research shows that a correlationbetweenmotivation, excelling at work, improved productivity and fulfilment and expectancyexist. The reason why individuals act in a specific manner and choose not to act in a certain way can be directly linked totheirmotivation and engagement.As a member ofthe construction industry in South Africa, Stefanutti Stocks isseen as one of the leading construction groups. Employing more than 12 000 workers it has the ability to provide a wide variety of different scale projects for a host of clients in varied markets. The division concentrated on in this study is the Roads, Pipelines and Mining Services (RPM)Business Unit. The MD of the RPM Business Unit when starting at the company a few years ago came to the conclusion that in order for the RPM Business Unit to function optimally certain business inconsistencies regarding employee engagement needed to be addressed. Based on this he decided to use a consulting firm, AIM,to establish what the exact concernswere and what interventions wererequired to deal with them. ivInterventions facilitatedby AIM includedManagement Training Programmes and Workshops as well as one-on-one coaching sessions with selected individuals.The methodology used in this study was to measurethe current level of employee engagement subsequent toengagement interventionsconcludedby AIM.The approach used was the use of surveys distributed through AIM in conjunction with the RPM Business Unit’sHR Department. The surveys were distributed via Survey Monkey Software owned by the RPM Business Unit of Stefanutti Stocks. , Thesis (MBA) -- Faculty of Business and Economic Sciences, NMMU Business School, 2021
- Full Text:
- Date Issued: 2021-04
A model to predict the development of preeclampsia in South African women
- Authors: Smith, Nathan
- Date: 2022-12
- Subjects: Medical instruments and apparatus -- Design and construction , Hypertension in pregnancy -- measurements-- South Africa , Fetus -- Physiology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59980 , vital:62724
- Description: Preeclampsia is the new onset of hypertension and is one of the leading causes of maternal mortality in South Africa and the world. Preeclampsia is usually diagnosed after 20 weeks’ gestation. Due to South Africa’s poor level of antenatal care, the prediction of pregnant women at risk of developing preeclampsia can be an essential component of improving the level of antenatal. This study used an antenatal care dataset from a South African obstetrician. A review of the literature and existing systems was conducted to identify the eight risk factors. These risk factors are systolic blood pressure, diastolic blood pressure, maternal age, body mass index, diabetes status, hypertension history, nulliparity, and maternal disease. This study used antenatal care datasets from a South African obstetrician. Two models were developed that could accurately predict the development of preeclampsia, one before 16 weeks’ gestation and the other within three check-ups. The model was evaluated using five evaluation metrics: classification accuracy, area under the curve, precision, recall and F-Score. The results of this study show a promising future for the use of machine learning models in health care. To the researcher’s knowledge, this model is the first machine learning model for predicting preeclampsia using a South African dataset. Future work will revolve around validating the model on data collected from field studies in hospitals and clinics around South Africa , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Smith, Nathan
- Date: 2022-12
- Subjects: Medical instruments and apparatus -- Design and construction , Hypertension in pregnancy -- measurements-- South Africa , Fetus -- Physiology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59980 , vital:62724
- Description: Preeclampsia is the new onset of hypertension and is one of the leading causes of maternal mortality in South Africa and the world. Preeclampsia is usually diagnosed after 20 weeks’ gestation. Due to South Africa’s poor level of antenatal care, the prediction of pregnant women at risk of developing preeclampsia can be an essential component of improving the level of antenatal. This study used an antenatal care dataset from a South African obstetrician. A review of the literature and existing systems was conducted to identify the eight risk factors. These risk factors are systolic blood pressure, diastolic blood pressure, maternal age, body mass index, diabetes status, hypertension history, nulliparity, and maternal disease. This study used antenatal care datasets from a South African obstetrician. Two models were developed that could accurately predict the development of preeclampsia, one before 16 weeks’ gestation and the other within three check-ups. The model was evaluated using five evaluation metrics: classification accuracy, area under the curve, precision, recall and F-Score. The results of this study show a promising future for the use of machine learning models in health care. To the researcher’s knowledge, this model is the first machine learning model for predicting preeclampsia using a South African dataset. Future work will revolve around validating the model on data collected from field studies in hospitals and clinics around South Africa , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-12
A systematic methodology to evaluating optimised machine learning based network intrusion detection systems
- Authors: Chindove, Hatitye Ethridge
- Date: 2022-10-14
- Subjects: Intrusion detection systems (Computer security) , Machine learning , Computer networks Security measures , Principal components analysis
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/362774 , vital:65361
- Description: A network intrusion detection system (NIDS) is essential for mitigating computer network attacks in various scenarios. However, the increasing complexity of computer networks and attacks makes classifying unseen or novel network traffic challenging. Supervised machine learning techniques (ML) used in a NIDS can be affected by different scenarios. Thus, dataset recency, size, and applicability are essential factors when selecting and tuning a machine learning classifier. This thesis explores developing and optimising several supervised ML algorithms with relatively new datasets constructed to depict real-world scenarios. The methodology includes empirical analyses of systematic ML-based NIDS for a near real-world network system to improve intrusion detection. The thesis is experimental heavy for model assessment. Data preparation methods are explored, followed by feature engineering techniques. The model evaluation process involves three experiments testing against a validation, un-trained, and retrained set. They compare several traditional machine learning and deep learning classifiers to identify the best NIDS model. Results show that the focus on feature scaling, feature selection methods and ML algo- rithm hyper-parameter tuning per model is an essential optimisation component. Distance based ML algorithm performed much better with quantile transformation whilst the tree based algorithms performed better without scaling. Permutation importance performs as a feature selection method compared to feature extraction using Principal Component Analysis (PCA) when applied against all ML algorithms explored. Random forests, Sup- port Vector Machines and recurrent neural networks consistently achieved the best results with high macro f1-score results of 90% 81% and 73% for the CICIDS 2017 dataset; and 72% 68% and 73% against the CICIDS 2018 dataset. , Thesis (MSc) -- Faculty of Science, Computer Science, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Chindove, Hatitye Ethridge
- Date: 2022-10-14
- Subjects: Intrusion detection systems (Computer security) , Machine learning , Computer networks Security measures , Principal components analysis
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/362774 , vital:65361
- Description: A network intrusion detection system (NIDS) is essential for mitigating computer network attacks in various scenarios. However, the increasing complexity of computer networks and attacks makes classifying unseen or novel network traffic challenging. Supervised machine learning techniques (ML) used in a NIDS can be affected by different scenarios. Thus, dataset recency, size, and applicability are essential factors when selecting and tuning a machine learning classifier. This thesis explores developing and optimising several supervised ML algorithms with relatively new datasets constructed to depict real-world scenarios. The methodology includes empirical analyses of systematic ML-based NIDS for a near real-world network system to improve intrusion detection. The thesis is experimental heavy for model assessment. Data preparation methods are explored, followed by feature engineering techniques. The model evaluation process involves three experiments testing against a validation, un-trained, and retrained set. They compare several traditional machine learning and deep learning classifiers to identify the best NIDS model. Results show that the focus on feature scaling, feature selection methods and ML algo- rithm hyper-parameter tuning per model is an essential optimisation component. Distance based ML algorithm performed much better with quantile transformation whilst the tree based algorithms performed better without scaling. Permutation importance performs as a feature selection method compared to feature extraction using Principal Component Analysis (PCA) when applied against all ML algorithms explored. Random forests, Sup- port Vector Machines and recurrent neural networks consistently achieved the best results with high macro f1-score results of 90% 81% and 73% for the CICIDS 2017 dataset; and 72% 68% and 73% against the CICIDS 2018 dataset. , Thesis (MSc) -- Faculty of Science, Computer Science, 2022
- Full Text:
- Date Issued: 2022-10-14
Comparative analysis of the known Hop1b and the novel Hop1a isoforms of the Hop gene
- Authors: Makhubu, Portia
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164311 , vital:41108 , doi:10.21504/10962/164311
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
- Authors: Makhubu, Portia
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164311 , vital:41108 , doi:10.21504/10962/164311
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
Effectiveness of cost containment measures: the case of Harry Gwala District Municipality
- Authors: Lungwengwe, Neziswa
- Date: 2021-04
- Subjects: Activity-based costing , Cost accounting , Managerial accounting
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/51765 , vital:43370
- Description: The primary research objective of this case study was to understand the effectiveness of cost containment measures implemented by all departments at Harry Gwala District Municipality. The case study also explored factors that may have contributed to the implementation of cost containment measures to ensure that the municipality spends funds on essential items and avoids unauthorised expenditure. A case study with fourteen (14) participants was chosen in order to focus on a particular area that the researcher could easily monitor. The researcher mixed qualitative and quantitative research designs to maintain the strengths and improve the weaknesses in both designs. Audited Annual Financial Statements and approved budgets were analysed to assess the effectiveness of cost containment measures. The study found that while employees were aware of their roles and responsibilities, it is safe to say that they did not follow procedures to ensure that costs were maintained. The results of the study showed that the Municipal Public Accounts Committee (MPAC) had no financial background. There was generally no change in the behaviour of employees as far as cost containment measures were concerned. The current repairs and maintenance budget was far below the norm of 8% of the carrying value of municipal assets and the municipality only budgeted between 2 – 3% per year for the assets with a carrying value of about R2.3 billion. , Thesis (MBA) -- Faculty of Business and Economic Sciences , Business Administration, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Lungwengwe, Neziswa
- Date: 2021-04
- Subjects: Activity-based costing , Cost accounting , Managerial accounting
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/51765 , vital:43370
- Description: The primary research objective of this case study was to understand the effectiveness of cost containment measures implemented by all departments at Harry Gwala District Municipality. The case study also explored factors that may have contributed to the implementation of cost containment measures to ensure that the municipality spends funds on essential items and avoids unauthorised expenditure. A case study with fourteen (14) participants was chosen in order to focus on a particular area that the researcher could easily monitor. The researcher mixed qualitative and quantitative research designs to maintain the strengths and improve the weaknesses in both designs. Audited Annual Financial Statements and approved budgets were analysed to assess the effectiveness of cost containment measures. The study found that while employees were aware of their roles and responsibilities, it is safe to say that they did not follow procedures to ensure that costs were maintained. The results of the study showed that the Municipal Public Accounts Committee (MPAC) had no financial background. There was generally no change in the behaviour of employees as far as cost containment measures were concerned. The current repairs and maintenance budget was far below the norm of 8% of the carrying value of municipal assets and the municipality only budgeted between 2 – 3% per year for the assets with a carrying value of about R2.3 billion. , Thesis (MBA) -- Faculty of Business and Economic Sciences , Business Administration, 2021
- Full Text:
- Date Issued: 2021-04
Empty adjectives and excessive intensifiers, or savvy discourse moves? A feminist critical discourse study of gender-based differences in the discourse of businesspeople on LinkedIn
- Authors: Schmauss, Lindsay Susannah
- Date: 2023-10-13
- Subjects: Corpora (Linguistics) , Critical discourse analysis , Intensification (Linguistics) , Women's language , Adjective , Politeness (Linguistics)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/425111 , vital:72211
- Description: This Feminist Critical Discourse Analysis (FCDA) examines the use of ‘empty’ adjectives and the equative intensifier so in discourse on LinkedIn, a social network service (SNS) for businesspeople and professionals. These linguistic features soften the impact of what is said in ways that can conform with politeness norms that one should not impose a point of view but can also be negatively construed as weak, uncertain and unclear. The North American sociolinguist, Robin Tolmach Lakoff (1973, 1975, 2004), first associated these linguistic markers with a feminine register in her seminal work, Language and Women’s Place, arguing that there is a social expectation that women talk like a lady and follow politeness conventions, while the speech of men is not similarly constrained. That women are socially conditioned to speak in ways that can undermine their clarity and assertiveness would present a particular dilemma in the business context, where clear, direct and confident communication is valued. This corpus-based study explores the dilemma in the context of LinkedIn where the linguistic behaviour of cisgender women indeed showed evidence of their struggle between conflicting impulses to talk like a lady and a desire to be taken seriously as businesspeople. While the examined features mainly appeared in the discourse of women, it was interesting to note men making use of ‘empty’ adjectives and so in communication contexts where the goal appeared to be relationship-building. As notions of business leadership are evolving to value organisational leadership more, this suggests that linguistic devices that have traditionally been associated more with the communal conversation of the stereotypical ‘woman’ appear to be gaining wider acceptance and relevance, although in domains orientated towards the “soft skill” of building relationships, rather than the “hard work” of business. While the value talking like a lady may be shifting, language that is the opposite of talking like a lady seems to remain the language of serious talk, and the kind of gender-based linguistic discrimination first theorised by Lakoff seems thus to persist, also in the sphere of business discourse. , Thesis (MA) -- Faculty of Humanities, Linguistics and Applied Language Studies, 2023
- Full Text:
- Date Issued: 2023-10-13
- Authors: Schmauss, Lindsay Susannah
- Date: 2023-10-13
- Subjects: Corpora (Linguistics) , Critical discourse analysis , Intensification (Linguistics) , Women's language , Adjective , Politeness (Linguistics)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/425111 , vital:72211
- Description: This Feminist Critical Discourse Analysis (FCDA) examines the use of ‘empty’ adjectives and the equative intensifier so in discourse on LinkedIn, a social network service (SNS) for businesspeople and professionals. These linguistic features soften the impact of what is said in ways that can conform with politeness norms that one should not impose a point of view but can also be negatively construed as weak, uncertain and unclear. The North American sociolinguist, Robin Tolmach Lakoff (1973, 1975, 2004), first associated these linguistic markers with a feminine register in her seminal work, Language and Women’s Place, arguing that there is a social expectation that women talk like a lady and follow politeness conventions, while the speech of men is not similarly constrained. That women are socially conditioned to speak in ways that can undermine their clarity and assertiveness would present a particular dilemma in the business context, where clear, direct and confident communication is valued. This corpus-based study explores the dilemma in the context of LinkedIn where the linguistic behaviour of cisgender women indeed showed evidence of their struggle between conflicting impulses to talk like a lady and a desire to be taken seriously as businesspeople. While the examined features mainly appeared in the discourse of women, it was interesting to note men making use of ‘empty’ adjectives and so in communication contexts where the goal appeared to be relationship-building. As notions of business leadership are evolving to value organisational leadership more, this suggests that linguistic devices that have traditionally been associated more with the communal conversation of the stereotypical ‘woman’ appear to be gaining wider acceptance and relevance, although in domains orientated towards the “soft skill” of building relationships, rather than the “hard work” of business. While the value talking like a lady may be shifting, language that is the opposite of talking like a lady seems to remain the language of serious talk, and the kind of gender-based linguistic discrimination first theorised by Lakoff seems thus to persist, also in the sphere of business discourse. , Thesis (MA) -- Faculty of Humanities, Linguistics and Applied Language Studies, 2023
- Full Text:
- Date Issued: 2023-10-13
Factors affecting entrepreneurial activity in South African communities: factors inhibiting small, medium, and micro informal traders in Gqeberha
- Authors: Fritz, Laverne
- Date: 2025-04
- Subjects: Informal sector (Economics) -- South Africa -- Port Elizabeth , Small business -- South Africa -- Port Elizabeth , Entrepreneurship -- South Africa -- Port Elizabeth
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/72680 , vital:79247
- Description: This study investigates the factors that inhibit small, medium and micro informal traders in Gqeberha. The concept of the economically excluded entrepreneur is central to the study, which examines the interaction of entrepreneurial mindset together with the liabilities of poorness, newness and smallness which impede economically excluded entrepreneurs from starting new ventures. This study contextualises both the formal and informal South African economies and emphasises the economic obstacles and personal pressures experienced by economically excluded entrepreneurs. To achieve the aim and objectives of the study, a qualitative approach was utilised. Semi-structured interviews were conducted, utilising purposive and convenience sampling methods to collect data from 15 economically excluded small, medium and micro informal traders in Gqeberha. The collected data were analysed using ATLAS.ti software. The study identified several factors that discourage entrepreneurship amongst economically excluded entrepreneurs including financial constraints, limited access to resources, a lack of planning orientation and personal pressures. It also highlighted key obstacles faced by these entrepreneurs such as absence of mentorship and support networks, barriers to market entry, insufficient financial and business literacy and a shortage or absence of physical tools and materials. Additionally, the study outlined support requirements these entrepreneurs require to effectively operate their businesses on a day-today basis. Understanding the factors that discourage, obstruct and support economically excluded entrepreneurs is important to determine how to assist economically excluded entrepreneurs prior to and during their entrepreneurial endeavours. The findings of this study provide a foundation for local and national government as well as established businesses to assist small, medium and micro informal traders thrive, thereby contributing to the broader goal of sustainable economic growth through entrepreneurship. Future research can explore the effectiveness of innovation hubs, where nascent economically excluded entrepreneurs can receive mentorship and acquire the necessary entrepreneurial skills for business success. , Thesis (MBA) -- Faculty of Business and Economic Sciences, Business School, 2025
- Full Text:
- Date Issued: 2025-04
- Authors: Fritz, Laverne
- Date: 2025-04
- Subjects: Informal sector (Economics) -- South Africa -- Port Elizabeth , Small business -- South Africa -- Port Elizabeth , Entrepreneurship -- South Africa -- Port Elizabeth
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/72680 , vital:79247
- Description: This study investigates the factors that inhibit small, medium and micro informal traders in Gqeberha. The concept of the economically excluded entrepreneur is central to the study, which examines the interaction of entrepreneurial mindset together with the liabilities of poorness, newness and smallness which impede economically excluded entrepreneurs from starting new ventures. This study contextualises both the formal and informal South African economies and emphasises the economic obstacles and personal pressures experienced by economically excluded entrepreneurs. To achieve the aim and objectives of the study, a qualitative approach was utilised. Semi-structured interviews were conducted, utilising purposive and convenience sampling methods to collect data from 15 economically excluded small, medium and micro informal traders in Gqeberha. The collected data were analysed using ATLAS.ti software. The study identified several factors that discourage entrepreneurship amongst economically excluded entrepreneurs including financial constraints, limited access to resources, a lack of planning orientation and personal pressures. It also highlighted key obstacles faced by these entrepreneurs such as absence of mentorship and support networks, barriers to market entry, insufficient financial and business literacy and a shortage or absence of physical tools and materials. Additionally, the study outlined support requirements these entrepreneurs require to effectively operate their businesses on a day-today basis. Understanding the factors that discourage, obstruct and support economically excluded entrepreneurs is important to determine how to assist economically excluded entrepreneurs prior to and during their entrepreneurial endeavours. The findings of this study provide a foundation for local and national government as well as established businesses to assist small, medium and micro informal traders thrive, thereby contributing to the broader goal of sustainable economic growth through entrepreneurship. Future research can explore the effectiveness of innovation hubs, where nascent economically excluded entrepreneurs can receive mentorship and acquire the necessary entrepreneurial skills for business success. , Thesis (MBA) -- Faculty of Business and Economic Sciences, Business School, 2025
- Full Text:
- Date Issued: 2025-04
Selection for improved virulence of Cryptophlebia peltastica nucleopolyhedrovirus (CrpeNPV) to False Codling Moth, Thaumatotibia leucotreta, by serial passage through a heterologous host
- Authors: Iita, Petrus Paulus
- Date: 2021-04
- Subjects: Cryptophlebia leucotreta -- Biological control , Biological pest control agents , Citrus -- Diseases and pests , Baculoviruses , Cryptophlebia peltastica nucleopolyhedrovirus (CrpeNPV)
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178180 , vital:42918
- Description: The false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is endemic to southern Africa, and strongly associated with citrus. As South African citrus production is mainly for export to foreign markets, the market access risk due to the phytosanitary status of this pest is considerable and its control is therefore imperative. Various control measures as part of a rigorous integrated pest management (IPM) programme targeted against T. leucotreta have been effective at suppressing the pest in citrus, but there is still a growing need for continued improvement of the programme and augmentation of the available control options. Of these control options, biological control, particularly the use of Cryptophlebia leucotreta granulovirus (CrleGV-SA), is a key component of IPM in citrus orchards and it has been very successful at reducing T. leucotreta populations in the field for almost two decades. There is however, a growing need for more baculovirus variants with an improved virulence against T. leucotreta for a more efficient pest management system. The newly identified insect virus, Cryptophlebia peltastica nucleopolyhedrovirus (CrpeNPV) offers a unique opportunity for an additional biopesticide in IPM for control of T. leucotreta in the field. This study aimed to conduct serial passaging of CrpeNPV through a heterologous host, T. leucotreta, in order to determine the potential for improved virulence or speed of kill against it. In order to select for a variant of CrpeNPV with improved virulence against T. leucotreta, a high dose (LC90) of the virus OBs was used to perform 12 serial passages through T. leucotreta larvae in surface-dose bioassays. Whole genome sequencing and analysis of the passaged virus, along with restriction endonuclease profiling in silico was performed to determine if the genetic identity of the virus had changed during serial passage, in relation to the original virus. These analyses indicated that the dominant genotype of CrpeNPV was maintained following 12 serial passages through the heterologous host. The biological activity of the passaged virus, along with the original virus was evaluated against neonate T. leucotreta in surface-dose bioassays and compared. Results from dose-response bioassays showed that the virulence of CrpeNPV did not improve after 12 serial passages. The LC50 values of the passaged virus and the original virus were estimated at 1.96 × 104 and 1.58 × 104 OBs/ml, respectively, whereas the LC90 values were estimated at 3.46 × 104 OBs/ml for the passaged virus and 3.68 × 104 for the original virus. Similarly, the results from time-response bioassays showed that the speed of kill of CrpeNPV did not improve after 12 serial passages. The LT50 values of the passaged virus and the original virus were 88.44 hours (3 days and 16 hours) and 83.74 hours (3 days and 12 hours), respectively, whereas the LT90 values were 115 hours (4 days 19 hours) for the passaged virus and 102 hours (4 days 6 hours) for the original virus. The virulence and speed of kill of the passaged virus decreased significantly, in relation to the original virus. When the full genome of the passaged virus was sequenced and analysed, only a few SNPs were detected in the viral genome, in comparison to the original virus. No detectable difference in REN digestion patterns were observed following REN analysis of gDNA of the passaged virus with several restriction enzymes in silico. The results for this study suggest that CrpeNPV may already be optimally suited to the heterologous host as it persists under these conditions without significant changes to the genome. These results have positive implications for the genetic integrity of CrpeNPV as a potential biocontrol agent in the field. This study is the first to report the virulence selection of CrpeNPV by serial passage through a heterologous host, and also the first to record bioassay data in terms of dose response (or lethal concentration) against T. leucotreta second instars. The data obtained have added to the knowledge about interactions between CrpeNPV and its heterologous host, and may be fundamental to continued investigation into the effect of serial passage on pathogenicity and genetic diversity of CrpeNPV. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Iita, Petrus Paulus
- Date: 2021-04
- Subjects: Cryptophlebia leucotreta -- Biological control , Biological pest control agents , Citrus -- Diseases and pests , Baculoviruses , Cryptophlebia peltastica nucleopolyhedrovirus (CrpeNPV)
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178180 , vital:42918
- Description: The false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is endemic to southern Africa, and strongly associated with citrus. As South African citrus production is mainly for export to foreign markets, the market access risk due to the phytosanitary status of this pest is considerable and its control is therefore imperative. Various control measures as part of a rigorous integrated pest management (IPM) programme targeted against T. leucotreta have been effective at suppressing the pest in citrus, but there is still a growing need for continued improvement of the programme and augmentation of the available control options. Of these control options, biological control, particularly the use of Cryptophlebia leucotreta granulovirus (CrleGV-SA), is a key component of IPM in citrus orchards and it has been very successful at reducing T. leucotreta populations in the field for almost two decades. There is however, a growing need for more baculovirus variants with an improved virulence against T. leucotreta for a more efficient pest management system. The newly identified insect virus, Cryptophlebia peltastica nucleopolyhedrovirus (CrpeNPV) offers a unique opportunity for an additional biopesticide in IPM for control of T. leucotreta in the field. This study aimed to conduct serial passaging of CrpeNPV through a heterologous host, T. leucotreta, in order to determine the potential for improved virulence or speed of kill against it. In order to select for a variant of CrpeNPV with improved virulence against T. leucotreta, a high dose (LC90) of the virus OBs was used to perform 12 serial passages through T. leucotreta larvae in surface-dose bioassays. Whole genome sequencing and analysis of the passaged virus, along with restriction endonuclease profiling in silico was performed to determine if the genetic identity of the virus had changed during serial passage, in relation to the original virus. These analyses indicated that the dominant genotype of CrpeNPV was maintained following 12 serial passages through the heterologous host. The biological activity of the passaged virus, along with the original virus was evaluated against neonate T. leucotreta in surface-dose bioassays and compared. Results from dose-response bioassays showed that the virulence of CrpeNPV did not improve after 12 serial passages. The LC50 values of the passaged virus and the original virus were estimated at 1.96 × 104 and 1.58 × 104 OBs/ml, respectively, whereas the LC90 values were estimated at 3.46 × 104 OBs/ml for the passaged virus and 3.68 × 104 for the original virus. Similarly, the results from time-response bioassays showed that the speed of kill of CrpeNPV did not improve after 12 serial passages. The LT50 values of the passaged virus and the original virus were 88.44 hours (3 days and 16 hours) and 83.74 hours (3 days and 12 hours), respectively, whereas the LT90 values were 115 hours (4 days 19 hours) for the passaged virus and 102 hours (4 days 6 hours) for the original virus. The virulence and speed of kill of the passaged virus decreased significantly, in relation to the original virus. When the full genome of the passaged virus was sequenced and analysed, only a few SNPs were detected in the viral genome, in comparison to the original virus. No detectable difference in REN digestion patterns were observed following REN analysis of gDNA of the passaged virus with several restriction enzymes in silico. The results for this study suggest that CrpeNPV may already be optimally suited to the heterologous host as it persists under these conditions without significant changes to the genome. These results have positive implications for the genetic integrity of CrpeNPV as a potential biocontrol agent in the field. This study is the first to report the virulence selection of CrpeNPV by serial passage through a heterologous host, and also the first to record bioassay data in terms of dose response (or lethal concentration) against T. leucotreta second instars. The data obtained have added to the knowledge about interactions between CrpeNPV and its heterologous host, and may be fundamental to continued investigation into the effect of serial passage on pathogenicity and genetic diversity of CrpeNPV. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-04
Softboi
- Authors: Mall, Shireen
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/164373 , vital:41113
- Description: Thesis (MA)--Rhodes University, Faculty of Humanities, School of Languages, 2020
- Full Text:
- Date Issued: 2020
- Authors: Mall, Shireen
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/164373 , vital:41113
- Description: Thesis (MA)--Rhodes University, Faculty of Humanities, School of Languages, 2020
- Full Text:
- Date Issued: 2020
Stable Covalent pH-Sensitive Metallophthalocyanines Thin Monolayer Films for Selective Detection of Neurotransmitters
- Idowu, Abosede Omowumi Atinuke
- Authors: Idowu, Abosede Omowumi Atinuke
- Date: 2021-10-29
- Subjects: Neurotransmitters , Phthalocyanines , Monomolecular films , Nervous system Degeneration
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192922 , vital:45279 , DOI 10.21504/10962/192922
- Description: The global challenge in solving the problem of neurodegenerative diseases (NDDs) that affect neurons in the human brain is to date unresolved. The statistical population of the affected people increases each year. Neurons are prone to damage or death as a result of an imbalanced level of released neurotransmitters (NTs). These imbalances affect the proper functioning of the brain and body. Early detection of the imbalances of NTs could suppress or correct the symptoms of NDDs. The detection has been the focus of researchers employing different techniques for both in-vivo and in-vitro detection of NTs. The research is based on electrochemical technique due to its fast response with adequate qualitative and quantitative results. The electrochemical methods are easy to handle, and the working electrode in the system can be modified for a specific purpose. The materials used in this work were the first-row transition metals octacarboxyphenoxy phthalocyanines complexes. The complexes were immobilized onto gold electrode surfaces and used as electrocatalysts for the detection of NTs. The immobilization method used to modify gold electrode was highly stable throughout the analyses in this study. The complexes improved the efficiency of the gold electrodes towards the detection of the NTs and suppressed the presence of ascorbic acid as a strong interference. The focus of this research is to solve the problem of interference faced during the detection of NTs. The thin film of octacarboxyphenoxy metallophthalocyanines was immobilized onto the gold electrode. The complexes, due to their catalytic activity, detected dopamine, epinephrine, serotonin and norepinephrine accurately. The range of detection of prominent chemicals associated with NTs was done using electroanalytical methods. Due to the pH sensitive functional groups (COOH), the thin monolayer phthalocyanine films suppressed ascorbic acid interference. The electrochemical analysis of neurotransmitters gave excellent limit of detection at μM range for all studied NTs. The results obtained with the modified electrode are proof of good electrocatalytic abilities of the complexes synthesized. This study recommends the use of the methods in this work for development of electrodes for NTs detection in human serum and tissue samples. , Thesis (PhD) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Idowu, Abosede Omowumi Atinuke
- Date: 2021-10-29
- Subjects: Neurotransmitters , Phthalocyanines , Monomolecular films , Nervous system Degeneration
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192922 , vital:45279 , DOI 10.21504/10962/192922
- Description: The global challenge in solving the problem of neurodegenerative diseases (NDDs) that affect neurons in the human brain is to date unresolved. The statistical population of the affected people increases each year. Neurons are prone to damage or death as a result of an imbalanced level of released neurotransmitters (NTs). These imbalances affect the proper functioning of the brain and body. Early detection of the imbalances of NTs could suppress or correct the symptoms of NDDs. The detection has been the focus of researchers employing different techniques for both in-vivo and in-vitro detection of NTs. The research is based on electrochemical technique due to its fast response with adequate qualitative and quantitative results. The electrochemical methods are easy to handle, and the working electrode in the system can be modified for a specific purpose. The materials used in this work were the first-row transition metals octacarboxyphenoxy phthalocyanines complexes. The complexes were immobilized onto gold electrode surfaces and used as electrocatalysts for the detection of NTs. The immobilization method used to modify gold electrode was highly stable throughout the analyses in this study. The complexes improved the efficiency of the gold electrodes towards the detection of the NTs and suppressed the presence of ascorbic acid as a strong interference. The focus of this research is to solve the problem of interference faced during the detection of NTs. The thin film of octacarboxyphenoxy metallophthalocyanines was immobilized onto the gold electrode. The complexes, due to their catalytic activity, detected dopamine, epinephrine, serotonin and norepinephrine accurately. The range of detection of prominent chemicals associated with NTs was done using electroanalytical methods. Due to the pH sensitive functional groups (COOH), the thin monolayer phthalocyanine films suppressed ascorbic acid interference. The electrochemical analysis of neurotransmitters gave excellent limit of detection at μM range for all studied NTs. The results obtained with the modified electrode are proof of good electrocatalytic abilities of the complexes synthesized. This study recommends the use of the methods in this work for development of electrodes for NTs detection in human serum and tissue samples. , Thesis (PhD) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10-29
Suitability of a triply periodic minimal surface lattice heat exchanger for an electrical vehicle cooling system
- Authors: van Aswegen, Wian
- Date: 2025-04
- Subjects: Electric vehicles -- Cooling , Electric automobiles -- Design and construction , Heat pipes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/74231 , vital:79670
- Description: Many automotive OEMs have introduced electrical vehicles (EVs) into their current and future production outputs on an accelerated basis. The many benefits of EVs are clear and evident, but it is still a comparatively new sector compared to established internal combustion engine (ICE) vehicles that have dominated the automotive landscape over the last century. Therefore, many challenges face the Design Engineer in this sector. As a result, research and development in EVs is accelerating across all component systems in contemporary automotive manufacturing. The cooling systems of EVs is an area that tends to be more complex than their ICE counterparts as there are not only more components that require regulating and cooling, but the criticality of these systems is considerably more constrained than typical internal combustion (IC) systems. EV cooling systems make use of specialist battery systems and electrical components which occupy a large amount of space within the vehicle design space and require advanced thermal control. These large number of batteries and components invariably means that EVs tend to be generally very heavy vehicles. The objective of this research is to design, simulate, manufacture and test an additively manufactured (AM) cooling system for an EV while focusing on minimizing material, consolidation of parts and enhancing heat transfer efficiency. AM allows the Design Engineer significant freedom as complex structures can be manufactured that would not typically be possible with traditional subtractive and formative methods. This additive process allows for unique, conformal and compact components to be produced, which still maintain excellent functionality. The heat exchanger design in this study investigated lattice structures, increasing the conductive surface area available for heat transfer. Various heat exchanger designs were simulated and physically tested to determine their ability to transfer heat effectively. When comparing the heat transfer performance of the AM cooling system to that of a traditionally used EV cooling system it was identified that AM heat exchangers can provide a better cooling performance relative to the traditional radiators. This research shows that, compared to a traditional radiator, a smaller and more lightweight AM heat exchanger can produce the needed thermal cooling for an EV cooling system. Thus, proving that AM is a viable option for the future of the EV industry. , Thesis (MEng) -- Faculty of Engineering, the Built Environment, and Technology, School of Engineering, 2025
- Full Text:
- Date Issued: 2025-04
- Authors: van Aswegen, Wian
- Date: 2025-04
- Subjects: Electric vehicles -- Cooling , Electric automobiles -- Design and construction , Heat pipes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/74231 , vital:79670
- Description: Many automotive OEMs have introduced electrical vehicles (EVs) into their current and future production outputs on an accelerated basis. The many benefits of EVs are clear and evident, but it is still a comparatively new sector compared to established internal combustion engine (ICE) vehicles that have dominated the automotive landscape over the last century. Therefore, many challenges face the Design Engineer in this sector. As a result, research and development in EVs is accelerating across all component systems in contemporary automotive manufacturing. The cooling systems of EVs is an area that tends to be more complex than their ICE counterparts as there are not only more components that require regulating and cooling, but the criticality of these systems is considerably more constrained than typical internal combustion (IC) systems. EV cooling systems make use of specialist battery systems and electrical components which occupy a large amount of space within the vehicle design space and require advanced thermal control. These large number of batteries and components invariably means that EVs tend to be generally very heavy vehicles. The objective of this research is to design, simulate, manufacture and test an additively manufactured (AM) cooling system for an EV while focusing on minimizing material, consolidation of parts and enhancing heat transfer efficiency. AM allows the Design Engineer significant freedom as complex structures can be manufactured that would not typically be possible with traditional subtractive and formative methods. This additive process allows for unique, conformal and compact components to be produced, which still maintain excellent functionality. The heat exchanger design in this study investigated lattice structures, increasing the conductive surface area available for heat transfer. Various heat exchanger designs were simulated and physically tested to determine their ability to transfer heat effectively. When comparing the heat transfer performance of the AM cooling system to that of a traditionally used EV cooling system it was identified that AM heat exchangers can provide a better cooling performance relative to the traditional radiators. This research shows that, compared to a traditional radiator, a smaller and more lightweight AM heat exchanger can produce the needed thermal cooling for an EV cooling system. Thus, proving that AM is a viable option for the future of the EV industry. , Thesis (MEng) -- Faculty of Engineering, the Built Environment, and Technology, School of Engineering, 2025
- Full Text:
- Date Issued: 2025-04
The feasibility of task-shifting prolonged exposure for Primary Care (PE-PC) for PTSD within a low resource community in the Eastern Cape
- Shabangu, Princess Noxolo Nonhlanhla
- Authors: Shabangu, Princess Noxolo Nonhlanhla
- Date: 2024-04-04
- Subjects: Task shifting , Prolonged exposure therapy , Post-traumatic stress disorder , Primary health care , Community psychiatry South Africa Eastern Cape
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/435479 , vital:73161
- Description: Although high levels of trauma exposure potentiate an alarming prevalence of PTSD, increasing the need for trauma-focused treatment, the South African health system is unable to care for the population. The South African healthcare system contains a range of systemic and structural inefficiencies, including suboptimal care and shortages of healthcare professionals. PE-PC offers a resource-constrained mental healthcare system solution by integrating an evidence-based intervention (EBI) in primary care settings. Likewise, the present study acknowledges the ratio of mental healthcare professionals to patients in low- and middle-income countries (LMIC). It explores task shifting to expand mental healthcare to primary care settings. The study follows qualitative healthcare design research to explore the experiences and perceptions of the two cohorts of trauma support workers (TSW) from Rhode University and the Joza community in Makhanda. The feasibility of the PE-PC intervention in Makhanda was illustrated through the data obtained from the TSWs' experiences and perceptions of the intervention's utility. The present study presents an essential contribution to the sparse research conducted on treating PTSD in LMIC with shortages in healthcare professionals. The thematic findings look at the trauma support workers (TSWs) role, including some of its challenges, to explore the feasibility of interventions. Some of the themes highlighted unpack the perceived utility of task-shifting in low-resource contexts, the limitations thereof and considerations for future research. Notwithstanding the challenges, the data from the present study indicates that PE-PC can be feasibly task-shifted in low-resource contexts such as Makhanda. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
- Full Text:
- Date Issued: 2024-04-04
- Authors: Shabangu, Princess Noxolo Nonhlanhla
- Date: 2024-04-04
- Subjects: Task shifting , Prolonged exposure therapy , Post-traumatic stress disorder , Primary health care , Community psychiatry South Africa Eastern Cape
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/435479 , vital:73161
- Description: Although high levels of trauma exposure potentiate an alarming prevalence of PTSD, increasing the need for trauma-focused treatment, the South African health system is unable to care for the population. The South African healthcare system contains a range of systemic and structural inefficiencies, including suboptimal care and shortages of healthcare professionals. PE-PC offers a resource-constrained mental healthcare system solution by integrating an evidence-based intervention (EBI) in primary care settings. Likewise, the present study acknowledges the ratio of mental healthcare professionals to patients in low- and middle-income countries (LMIC). It explores task shifting to expand mental healthcare to primary care settings. The study follows qualitative healthcare design research to explore the experiences and perceptions of the two cohorts of trauma support workers (TSW) from Rhode University and the Joza community in Makhanda. The feasibility of the PE-PC intervention in Makhanda was illustrated through the data obtained from the TSWs' experiences and perceptions of the intervention's utility. The present study presents an essential contribution to the sparse research conducted on treating PTSD in LMIC with shortages in healthcare professionals. The thematic findings look at the trauma support workers (TSWs) role, including some of its challenges, to explore the feasibility of interventions. Some of the themes highlighted unpack the perceived utility of task-shifting in low-resource contexts, the limitations thereof and considerations for future research. Notwithstanding the challenges, the data from the present study indicates that PE-PC can be feasibly task-shifted in low-resource contexts such as Makhanda. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
- Full Text:
- Date Issued: 2024-04-04
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