Associations between contraceptive use, physical activity, depression, and quality of life among women of childbearing age in Akure South Local Government area of Ondo State, Nigeria
- Authors: Alimi, Olabisi Ganiyat
- Date: 2023-10-13
- Subjects: Exercise for women Nigeria Ondo State , Depression in women Nigeria Ondo State , Well-being Nigeria Ondo State , Quality of life Nigeria Ondo State , Contraception Side effects
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424210 , vital:72133
- Description: Background: Population experts and policymakers are concerned about Nigeria's rapid annual population growth due to the country's high birth rate which was 5.3 births per woman in 2018. Fear of the side effects of modern contraceptives among Nigerian women contributes to the low rate of contraceptive use, which was reported to be 17% and 37% among married and sexually active unmarried women, respectively. Which is a significant cause of the high birth rate. Although the side effects of modern contraceptives on women's clinical and physiological variables are well known, studies examining the associations between contraceptive use and physical and psychosocial variables such as physical activity (PA), depression, and quality of life (QoL) in non-athletic Nigerian women of reproductive age are scarce. This study aimed to examine the associations between contraceptive use, PA, depression, and QoL among non-athletic women of childbearing age in Akure South Local Government, Ondo State, Nigeria. Methods: In a descriptive cross-sectional study, 646 women of childbearing age were recruited using the multistage sampling technique. The data of 496 current contraceptive users and 146 non-users were analysed, as 4 respondents did not respond regarding current contraceptive use status. The Global PA Questionnaire (GPAQ), Beck’s Depression Inventory (BDI) and World Health QoL Organization Quality of Life Brief (WHOQoL BREF) were used to assess respondents’ scores/levels of PA, depression and health-related quality of life (HRQoL). The GPAQ, BDI, and WHOQOL scores were compared between contraceptive users and non-users using non-parametric Quade Analysis of Covariance while age, married status, tribe, religion, and occupation were included covariates. PA, sedentary behaviour (SB), and BDI scores were categorized using guidelines. Contraceptive use/practice was the outcome variable. Pearson's chi-square test bivariate analysis and a multivariate logistic model were used to identify factors associated with contraceptive use (users and non-users). Crude and adjusted odds ratios and their confidence intervals were calculated to determine the significance of the association. The regression model was adjusted for age, marital status, religion, tribe, highest education level, occupation, awareness of contraceptives, current use, lifetime use, type, class, and duration of current contraception. “Statistical significance was set at p < 0.05. Results: The mean age of the respondents was 29.73±6.10 years. The contraceptive users and non-users were not significantly different regarding their ages (p = 0.135), marital status (p = 0.245), highest education (p = 0.444), occupation (p = 0.238), and tribe (p = 0.192). The respondents’ lifetime and point prevalence of contraceptive uptake was 93.6% and 77.3%, respectively, while 72 (12.8%) reported experiencing contraception-related side effects. Of the 496 respondents who currently practice contraception, 146 (29.4%) were hormonal contraceptive users. The majority of the respondents had moderate and mild levels of PA (48.5%) and depression (51.4%), respectively, and a significantly higher proportion of contraceptive users had minimal and moderate depression levels than the non-users (p = 0.018). The contraceptive users demonstrated significantly higher median scores of BDI (p = 0.02), Physical health QoL (p < 0.001), environment QoL (p = 0.033) and overall QoL (0.004) than the non-users. Hormonal contraceptive users had significantly higher median PA walking/bicycling scores than non-hormonal users (p = 0.014). Respondents with mild and moderate depression levels had higher odds of being contraceptive users than those with minimal depression (AOR = 3.12, 95% CI = 1.43 – 6.80, p = 0.04 and 4.67, 95% CI = 1.92 – 11.36, p = 0.001 respectively). Conclusion: Contraceptive use is negatively associated with depression but positively related to Physical health, environment and overall domains of HRQoL. Healthcare professionals should consider women's mental and emotional condition while advising on family planning for optimal HRQoL. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2023
- Full Text:
- Date Issued: 2023-10-13
- Authors: Alimi, Olabisi Ganiyat
- Date: 2023-10-13
- Subjects: Exercise for women Nigeria Ondo State , Depression in women Nigeria Ondo State , Well-being Nigeria Ondo State , Quality of life Nigeria Ondo State , Contraception Side effects
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424210 , vital:72133
- Description: Background: Population experts and policymakers are concerned about Nigeria's rapid annual population growth due to the country's high birth rate which was 5.3 births per woman in 2018. Fear of the side effects of modern contraceptives among Nigerian women contributes to the low rate of contraceptive use, which was reported to be 17% and 37% among married and sexually active unmarried women, respectively. Which is a significant cause of the high birth rate. Although the side effects of modern contraceptives on women's clinical and physiological variables are well known, studies examining the associations between contraceptive use and physical and psychosocial variables such as physical activity (PA), depression, and quality of life (QoL) in non-athletic Nigerian women of reproductive age are scarce. This study aimed to examine the associations between contraceptive use, PA, depression, and QoL among non-athletic women of childbearing age in Akure South Local Government, Ondo State, Nigeria. Methods: In a descriptive cross-sectional study, 646 women of childbearing age were recruited using the multistage sampling technique. The data of 496 current contraceptive users and 146 non-users were analysed, as 4 respondents did not respond regarding current contraceptive use status. The Global PA Questionnaire (GPAQ), Beck’s Depression Inventory (BDI) and World Health QoL Organization Quality of Life Brief (WHOQoL BREF) were used to assess respondents’ scores/levels of PA, depression and health-related quality of life (HRQoL). The GPAQ, BDI, and WHOQOL scores were compared between contraceptive users and non-users using non-parametric Quade Analysis of Covariance while age, married status, tribe, religion, and occupation were included covariates. PA, sedentary behaviour (SB), and BDI scores were categorized using guidelines. Contraceptive use/practice was the outcome variable. Pearson's chi-square test bivariate analysis and a multivariate logistic model were used to identify factors associated with contraceptive use (users and non-users). Crude and adjusted odds ratios and their confidence intervals were calculated to determine the significance of the association. The regression model was adjusted for age, marital status, religion, tribe, highest education level, occupation, awareness of contraceptives, current use, lifetime use, type, class, and duration of current contraception. “Statistical significance was set at p < 0.05. Results: The mean age of the respondents was 29.73±6.10 years. The contraceptive users and non-users were not significantly different regarding their ages (p = 0.135), marital status (p = 0.245), highest education (p = 0.444), occupation (p = 0.238), and tribe (p = 0.192). The respondents’ lifetime and point prevalence of contraceptive uptake was 93.6% and 77.3%, respectively, while 72 (12.8%) reported experiencing contraception-related side effects. Of the 496 respondents who currently practice contraception, 146 (29.4%) were hormonal contraceptive users. The majority of the respondents had moderate and mild levels of PA (48.5%) and depression (51.4%), respectively, and a significantly higher proportion of contraceptive users had minimal and moderate depression levels than the non-users (p = 0.018). The contraceptive users demonstrated significantly higher median scores of BDI (p = 0.02), Physical health QoL (p < 0.001), environment QoL (p = 0.033) and overall QoL (0.004) than the non-users. Hormonal contraceptive users had significantly higher median PA walking/bicycling scores than non-hormonal users (p = 0.014). Respondents with mild and moderate depression levels had higher odds of being contraceptive users than those with minimal depression (AOR = 3.12, 95% CI = 1.43 – 6.80, p = 0.04 and 4.67, 95% CI = 1.92 – 11.36, p = 0.001 respectively). Conclusion: Contraceptive use is negatively associated with depression but positively related to Physical health, environment and overall domains of HRQoL. Healthcare professionals should consider women's mental and emotional condition while advising on family planning for optimal HRQoL. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2023
- Full Text:
- Date Issued: 2023-10-13
The mathematical and pedagogical content knowledge that Namibian senior primary teachers draw on to develop their learners’ computational estimation
- Authors: Shigwedha, Emilia Ndilimeke
- Date: 2023-10-13
- Subjects: Mathematics Study and teaching (Primary) Namibia , Approximation theory , Pedagogical content knowledge , Mathematics teachers In-service training Namibia , Mathematics Namibia Outlines, syllabi, etc
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424108 , vital:72124
- Description: Computational estimation is important in the development of learners’ number sense. It is through the process of finding an approximate (but satisfactory) that learners can check the reasonableness of their answers to calculations, develop an understanding of place value and by implication the four number operations. It is the role of teachers to develop the computational estimation skills of learners. To do this, teachers need to have a sound knowledge of computational estimation, its value and how to teach it. This study thus seeks to explore and understand Namibian senior primary teachers’ mathematical and pedagogical content knowledge to develop their learners’ computation estimation knowledge. The research is guided by the following question: What mathematical and pedagogical content knowledge do senior primary mathematics teachers draw on to develop their learners’ computational estimation skills? The research is a qualitative interpretivist case study. Eight senior primary teachers of Mathematics from the Ohangwena region in Namibia participated in the study. Data was generated through questionnaires, a focus group interview and lesson observations. The Mathematics Knowledge for Teaching (Ball et al., 2008) and the Knowledge Quartet (Rowland, 2005) frameworks were used as both analytic and explanatory tools for the study. Key findings from the research are that teachers have knowledge of and use a variety of strategies for estimation, however, they only use the ‘rounding off’ strategy when teaching learners computational estimation. The teachers appear to teach computational estimation by first focusing on place value before moving on to ‘rounding off’ to the nearest 10s, 100s, 1000s and so forth. My research recommends that the National Institute of Educational Development together with the Ministry of Education, Art and Culture in Namibia, provide teachers with professional development opportunities on how to develop learners’ computational estimation. Such professional development will further develop teachers’ mathematical and pedagogical content knowledge. Furthermore, the Namibian syllabus should include a variety of strategies for computational estimation. , Thesis (MEd) -- Faculty of Education, Primary and Early Childhood Education, 2023
- Full Text:
- Date Issued: 2023-10-13
- Authors: Shigwedha, Emilia Ndilimeke
- Date: 2023-10-13
- Subjects: Mathematics Study and teaching (Primary) Namibia , Approximation theory , Pedagogical content knowledge , Mathematics teachers In-service training Namibia , Mathematics Namibia Outlines, syllabi, etc
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424108 , vital:72124
- Description: Computational estimation is important in the development of learners’ number sense. It is through the process of finding an approximate (but satisfactory) that learners can check the reasonableness of their answers to calculations, develop an understanding of place value and by implication the four number operations. It is the role of teachers to develop the computational estimation skills of learners. To do this, teachers need to have a sound knowledge of computational estimation, its value and how to teach it. This study thus seeks to explore and understand Namibian senior primary teachers’ mathematical and pedagogical content knowledge to develop their learners’ computation estimation knowledge. The research is guided by the following question: What mathematical and pedagogical content knowledge do senior primary mathematics teachers draw on to develop their learners’ computational estimation skills? The research is a qualitative interpretivist case study. Eight senior primary teachers of Mathematics from the Ohangwena region in Namibia participated in the study. Data was generated through questionnaires, a focus group interview and lesson observations. The Mathematics Knowledge for Teaching (Ball et al., 2008) and the Knowledge Quartet (Rowland, 2005) frameworks were used as both analytic and explanatory tools for the study. Key findings from the research are that teachers have knowledge of and use a variety of strategies for estimation, however, they only use the ‘rounding off’ strategy when teaching learners computational estimation. The teachers appear to teach computational estimation by first focusing on place value before moving on to ‘rounding off’ to the nearest 10s, 100s, 1000s and so forth. My research recommends that the National Institute of Educational Development together with the Ministry of Education, Art and Culture in Namibia, provide teachers with professional development opportunities on how to develop learners’ computational estimation. Such professional development will further develop teachers’ mathematical and pedagogical content knowledge. Furthermore, the Namibian syllabus should include a variety of strategies for computational estimation. , Thesis (MEd) -- Faculty of Education, Primary and Early Childhood Education, 2023
- Full Text:
- Date Issued: 2023-10-13
Pedagogical practices teachers use to teach reading lessons in the junior primary phase in Kavango West region’
- Authors: Shimafo, Hildegard
- Date: 2023-03-30
- Subjects: Reading (Primary) Namibia Kavango West , Pedagogy , Extensive reading , Primary school teachers Namibia Kavango West , School children Books and reading Namibia Kavango West
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408762 , vital:70523
- Description: Learning to read for meaning and enjoyment in the Junior Primary phase is an essential goal for every child during their primary schooling. Despite this, reading for meaning and enjoyment in the Namibian context, specifically for primary learners, remains a concern. Current research suggests that there are very few studies that have been done in Namibia that examine the pedagogical practices of Junior Primary teachers to develop learners’ reading competence. In view of that, this study focused on the pedagogical practices of Junior Primary teachers in mediating reading in their classrooms. The study is a qualitative interpretive case study using observation and interviews as tools to generate in-depth data on how teachers teach reading. The study sample comprised of three Junior Primary teachers from Grades 1-3 who participated in this study. The selection criteria were based on historical background and the culture of teaching reading lessons for Grade 1-3 teachers. The study revealed some factors that impede the teaching of reading. Amongst them are a lack of in-service training, language barriers, and the lack of resources. The study found that English used as the LoLT (Language of Learning and Teaching) at the school where the study took place made it difficult for the teachers to convey the correct information to the learners due to a lack of proficiency. The study revealed that this situation limited most of the learners’ reading opportunities. Theory of Practice Architecture (ToPA), in particular by Kemmis and Grootenboer (2008), was used as an explanatory and analytical tool. This research asked the questions: 1.What pedagogical practices do Junior Primary teachers employ to mediate reading? and 2. What factors enable and constrain the pedagogical practices of teachers? As a way forward, this study recommends for a compulsory reading program be instituted at Higher Education Institutions responsible for teacher education. This should empower the teachers to enter a Junior Primary classroom with more confidence to teach the various reading components. This study recommends continuous in-service courses for teachers. The study further recommends that the Ministry of Education, Arts and Culture make provisions for textbooks in all schools for all learners if the learners reading performance is to improve in Namibia. , Thesis (MEd) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-03-30
- Authors: Shimafo, Hildegard
- Date: 2023-03-30
- Subjects: Reading (Primary) Namibia Kavango West , Pedagogy , Extensive reading , Primary school teachers Namibia Kavango West , School children Books and reading Namibia Kavango West
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408762 , vital:70523
- Description: Learning to read for meaning and enjoyment in the Junior Primary phase is an essential goal for every child during their primary schooling. Despite this, reading for meaning and enjoyment in the Namibian context, specifically for primary learners, remains a concern. Current research suggests that there are very few studies that have been done in Namibia that examine the pedagogical practices of Junior Primary teachers to develop learners’ reading competence. In view of that, this study focused on the pedagogical practices of Junior Primary teachers in mediating reading in their classrooms. The study is a qualitative interpretive case study using observation and interviews as tools to generate in-depth data on how teachers teach reading. The study sample comprised of three Junior Primary teachers from Grades 1-3 who participated in this study. The selection criteria were based on historical background and the culture of teaching reading lessons for Grade 1-3 teachers. The study revealed some factors that impede the teaching of reading. Amongst them are a lack of in-service training, language barriers, and the lack of resources. The study found that English used as the LoLT (Language of Learning and Teaching) at the school where the study took place made it difficult for the teachers to convey the correct information to the learners due to a lack of proficiency. The study revealed that this situation limited most of the learners’ reading opportunities. Theory of Practice Architecture (ToPA), in particular by Kemmis and Grootenboer (2008), was used as an explanatory and analytical tool. This research asked the questions: 1.What pedagogical practices do Junior Primary teachers employ to mediate reading? and 2. What factors enable and constrain the pedagogical practices of teachers? As a way forward, this study recommends for a compulsory reading program be instituted at Higher Education Institutions responsible for teacher education. This should empower the teachers to enter a Junior Primary classroom with more confidence to teach the various reading components. This study recommends continuous in-service courses for teachers. The study further recommends that the Ministry of Education, Arts and Culture make provisions for textbooks in all schools for all learners if the learners reading performance is to improve in Namibia. , Thesis (MEd) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-03-30
Crop fields abandonment: assessing the dynamics of degradation in relation to leverage points for sustainable land management in the Macubeni catchment, South Africa
- Authors: Sibiya, Silindile
- Date: 2023-03-29
- Subjects: Land degradation , Sustainable land management , Multiple criteria decision making , Twelve leverage points , Soil erosion South Africa eMalahleni , ArcGIS
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422470 , vital:71945
- Description: Soil erosion is a major global environmental problem and a pervasive forms of land degradation that threatens land productivity and food and water security. Some of the biggest sources of sediment in catchments are previously cultivated lands. Regardless of this factor, the abandonment of cultivated fields is not well-researched. Sustainable land management (SLM) interventions can play a significant role in mitigating and halting land degradation. This study investigated the dynamics of degradation exhibited by crop fields and the potential impacts of SLM interventions, using a leverage points framework and a case study in the Macubeni catchment of South Africa. The research answers three questions: (1) What is the relationship between the usage status of crop fields and degradation in Macubeni? (2) What are the drivers of crop field abandonment and how do they interact in the system? (3) Can proposed sustainable land management interventions tackle the dynamics of land abandonment, and associated degradation, at the root cause level? An empirical-analytical approach using a four step multi-method process was followed, in which crop fields were mapped using ArcGIS tools, literature was reviewed alongside stakeholder engagements, qualitative systems mapping modelling was undertaken, and a Multi-Criteria Analysis (MCA) with leverage points hierarchy was used to integrate all the steps together. The results revealed that the various drivers of crop field abandonment include natural environmental factors, socio-economic and social factors. 47.41% of the total crop fields in Macubeni were classified as highly degraded, and abandoned fields covered 37.47%. The statistical Chi-Square Test also confirmed that there is a significant relationship between the usage status and degradation level in crop fields. The SLM interventions assessed in the study have the potential to tackle the dynamics of land abandonment at a root cause level, however, there is a need to first shift the community’s mental models to address the existing sources of change resistance that are hindering successful implementation. Furthermore, the innovative multi-method approach applied in this study can further provide a holistic, dynamic, and integrated decision-support to land conservation and rehabilitation projects in similar settings across South Africa and other developing countries as opposed to the more traditional one-dimensional approaches. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2023
- Full Text:
- Date Issued: 2023-03-29
- Authors: Sibiya, Silindile
- Date: 2023-03-29
- Subjects: Land degradation , Sustainable land management , Multiple criteria decision making , Twelve leverage points , Soil erosion South Africa eMalahleni , ArcGIS
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422470 , vital:71945
- Description: Soil erosion is a major global environmental problem and a pervasive forms of land degradation that threatens land productivity and food and water security. Some of the biggest sources of sediment in catchments are previously cultivated lands. Regardless of this factor, the abandonment of cultivated fields is not well-researched. Sustainable land management (SLM) interventions can play a significant role in mitigating and halting land degradation. This study investigated the dynamics of degradation exhibited by crop fields and the potential impacts of SLM interventions, using a leverage points framework and a case study in the Macubeni catchment of South Africa. The research answers three questions: (1) What is the relationship between the usage status of crop fields and degradation in Macubeni? (2) What are the drivers of crop field abandonment and how do they interact in the system? (3) Can proposed sustainable land management interventions tackle the dynamics of land abandonment, and associated degradation, at the root cause level? An empirical-analytical approach using a four step multi-method process was followed, in which crop fields were mapped using ArcGIS tools, literature was reviewed alongside stakeholder engagements, qualitative systems mapping modelling was undertaken, and a Multi-Criteria Analysis (MCA) with leverage points hierarchy was used to integrate all the steps together. The results revealed that the various drivers of crop field abandonment include natural environmental factors, socio-economic and social factors. 47.41% of the total crop fields in Macubeni were classified as highly degraded, and abandoned fields covered 37.47%. The statistical Chi-Square Test also confirmed that there is a significant relationship between the usage status and degradation level in crop fields. The SLM interventions assessed in the study have the potential to tackle the dynamics of land abandonment at a root cause level, however, there is a need to first shift the community’s mental models to address the existing sources of change resistance that are hindering successful implementation. Furthermore, the innovative multi-method approach applied in this study can further provide a holistic, dynamic, and integrated decision-support to land conservation and rehabilitation projects in similar settings across South Africa and other developing countries as opposed to the more traditional one-dimensional approaches. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2023
- Full Text:
- Date Issued: 2023-03-29
The effects of temperature and exploitation on the behaviour of red roman Chrysoblephus laticeps (Sparidae) at baited video stations
- Authors: Mataboge, Bontle Boitumelo
- Date: 2022-04-06
- Subjects: Marine resources conservation South Africa Agulhas , Sparidae Effect of temperature on South Africa Agulhas , Sparidae Climatic factors South Africa Agulhas , Sparidae Effect of fishing on South Africa Agulhas , Sparidae Effect of human beings on South Africa Agulhas , Sparidae Behavior South Africa Agulhas , Overfishing South Africa Agulhas , Underwater videography in wildlife monitoring South Africa Agulhas , Red roman (Chrysoblephus laticeps)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291140 , vital:56823
- Description: Marine environments are experiencing rapidly increasing temperatures, sea levels and acidification and higher frequencies and magnitudes of extreme weather events as a result of climate change. In the Agulhas Ecoregion of South Africa, there has been an increase in the frequency and intensity of upwelling events. Upwelling events result in rapid and large decreases in water temperature which can persist for several days. Variation in water temperature is known to impact the metabolic rate of fish (which are ectotherms) and in turn their activity patterns. To promote fitness related traits, the metabolic rate of fish is maximised at a specific temperature range. Outside of this optimal temperature range, the capacity of fish to perform aerobically declines. Therefore, it is expected that an increase in upwelling may place the fish under significant physiological stress. The effects of climate change can be compounded by the effects of fisheries-induced evolution; the microevolution of a fish population due to the artificial selection of certain biological traits by fishing practices. Passive fishing gears preferentially remove large (older) and bold individuals, causing reductions in population size, genetic diversity and fecundity as well as size and age truncation and the loss of large, bold and dominant phenotypes in fish populations. These demographic changes affect the adaptive capacity of fish and exploited populations are expected to be less resilient to climate variability and long-term temperature change. The resilience of fish is largely dependent on their physiological attributes, particularly their metabolic rate. Theoretically, fish with broader aerobic scope (defined as the difference between an individual’s maximum metabolic rate and standard metabolic rate) will be more tolerant to the impacts of climate change as they have energy available for adaptation. Recent respirometry and accelerometry studies suggest that populations of the endemic southern African linefish Chrysoblephus laticeps (red roman) from inside marine protected areas (MPAs) have higher metabolic rates and broader aerobic scope compared to those found outside of MPAs, particularly at thermal extremes. As C. laticeps are highly resident it is possible that fish populations protected within well-established MPAs may be more resilient to the physiological stresses caused by upwelling if they are able to maintain their activity levels despite changing temperatures. Behaviour is a proxy that can be used to infer metabolism as behaviours have associated metabolic costs and benefits. Behaviour is also a trait that can be altered by passive fishing practices which preferentially extract more active and bold individuals. Given this context, the aim of this thesis was to determine the effects of short-term thermal variability on the population structure and behaviour of C. laticeps and whether these effects differed between protected and exploited populations. Baited remote underwater stereo-video systems (stereo-BRUVs) were used to observe C. laticeps inside two MPAs (Tsitsikamma and Goukamma) and at two exploited sites (Port Elizabeth and Cape St. Francis) over the temperature range 10-18 °C. The relative abundance, size and relevant behaviours of C. laticeps were recorded. The relative abundance (MaxN) of C. laticeps was not significantly higher inside the MPAs compared to the exploited sites. The size of C. laticeps did not vary significantly by protection level either. However, the mean size of C. laticeps was considerably smaller at Port Elizabeth compared to the three other locations. There was a notable absence of large C. laticeps size classes at Port Elizabeth. The effect of water temperature on relative abundance was only seen in the exploited areas, where temperature and abundance were positively correlated. This was not the case in the protected areas where C. laticeps abundance remained roughly consistent. Generally, the effect of temperature on all measured behaviours was consistent across protection levels. An exception was that the feeding rate at Tsitsikamma MPA was significantly higher than at Cape St. Francis at temperatures below 11.5 °C. Temperature had a significant effect on the time taken for the first individual to appear in the field of view. This time shortened with increasing temperature, regardless of protection level. This was likely a result of the metabolic constraints placed on individuals by low waters temperatures and individuals would be able to pursue the bait more readily at higher temperatures. However, there was no evidence of greater metabolic scope from the C. laticeps individuals observed in the MPAs, relative to the exploited areas. Individual size and the presence of conspecifics were also found to significantly influence behaviour. Generally, size had a positive relationship with behaviour, with larger individuals more likely to feed on the bait, chase other fish from the bait (only in the MPAs) and spend more time in the field of view. The higher displays of aggression in MPAs may be an indication of fishing practices having removed bold and dominant individuals at the exploited sites. The probability of fleeing and the feeding rates of individuals increased with increasing numbers of conspecifics, suggesting that C. laticeps behaviour is influenced by intraspecific competition. Overall, this thesis did not find strong evidence that C. laticeps from MPAs performed better than C. laticeps from exploited areas, even at low temperatures. Behavioural responses to temperature were highly variable across locations and this may be attributed to high behavioural phenotypic diversity among individuals. Environmental stressors, such as temperature changes, can illicit very different behavioural responses among individuals in a population. It is also possible that C. laticeps from the exploited areas have the same genetic predispositions to physiological stress as the individuals in the MPAs due to spillover and larval recruitment from the MPAs. Indeed, genetic studies find that all C. laticeps population in South African represent a single well-mixed genetic stock. It is likely that greater sampling effort is required to resolve the patterns in behaviour between exploited and protected populations. Nonetheless, given the influence of size on behaviour, the smaller size of C. laticeps at Port Elizabeth may be cause for concern regarding the vulnerability of future populations to ongoing climate change. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Mataboge, Bontle Boitumelo
- Date: 2022-04-06
- Subjects: Marine resources conservation South Africa Agulhas , Sparidae Effect of temperature on South Africa Agulhas , Sparidae Climatic factors South Africa Agulhas , Sparidae Effect of fishing on South Africa Agulhas , Sparidae Effect of human beings on South Africa Agulhas , Sparidae Behavior South Africa Agulhas , Overfishing South Africa Agulhas , Underwater videography in wildlife monitoring South Africa Agulhas , Red roman (Chrysoblephus laticeps)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291140 , vital:56823
- Description: Marine environments are experiencing rapidly increasing temperatures, sea levels and acidification and higher frequencies and magnitudes of extreme weather events as a result of climate change. In the Agulhas Ecoregion of South Africa, there has been an increase in the frequency and intensity of upwelling events. Upwelling events result in rapid and large decreases in water temperature which can persist for several days. Variation in water temperature is known to impact the metabolic rate of fish (which are ectotherms) and in turn their activity patterns. To promote fitness related traits, the metabolic rate of fish is maximised at a specific temperature range. Outside of this optimal temperature range, the capacity of fish to perform aerobically declines. Therefore, it is expected that an increase in upwelling may place the fish under significant physiological stress. The effects of climate change can be compounded by the effects of fisheries-induced evolution; the microevolution of a fish population due to the artificial selection of certain biological traits by fishing practices. Passive fishing gears preferentially remove large (older) and bold individuals, causing reductions in population size, genetic diversity and fecundity as well as size and age truncation and the loss of large, bold and dominant phenotypes in fish populations. These demographic changes affect the adaptive capacity of fish and exploited populations are expected to be less resilient to climate variability and long-term temperature change. The resilience of fish is largely dependent on their physiological attributes, particularly their metabolic rate. Theoretically, fish with broader aerobic scope (defined as the difference between an individual’s maximum metabolic rate and standard metabolic rate) will be more tolerant to the impacts of climate change as they have energy available for adaptation. Recent respirometry and accelerometry studies suggest that populations of the endemic southern African linefish Chrysoblephus laticeps (red roman) from inside marine protected areas (MPAs) have higher metabolic rates and broader aerobic scope compared to those found outside of MPAs, particularly at thermal extremes. As C. laticeps are highly resident it is possible that fish populations protected within well-established MPAs may be more resilient to the physiological stresses caused by upwelling if they are able to maintain their activity levels despite changing temperatures. Behaviour is a proxy that can be used to infer metabolism as behaviours have associated metabolic costs and benefits. Behaviour is also a trait that can be altered by passive fishing practices which preferentially extract more active and bold individuals. Given this context, the aim of this thesis was to determine the effects of short-term thermal variability on the population structure and behaviour of C. laticeps and whether these effects differed between protected and exploited populations. Baited remote underwater stereo-video systems (stereo-BRUVs) were used to observe C. laticeps inside two MPAs (Tsitsikamma and Goukamma) and at two exploited sites (Port Elizabeth and Cape St. Francis) over the temperature range 10-18 °C. The relative abundance, size and relevant behaviours of C. laticeps were recorded. The relative abundance (MaxN) of C. laticeps was not significantly higher inside the MPAs compared to the exploited sites. The size of C. laticeps did not vary significantly by protection level either. However, the mean size of C. laticeps was considerably smaller at Port Elizabeth compared to the three other locations. There was a notable absence of large C. laticeps size classes at Port Elizabeth. The effect of water temperature on relative abundance was only seen in the exploited areas, where temperature and abundance were positively correlated. This was not the case in the protected areas where C. laticeps abundance remained roughly consistent. Generally, the effect of temperature on all measured behaviours was consistent across protection levels. An exception was that the feeding rate at Tsitsikamma MPA was significantly higher than at Cape St. Francis at temperatures below 11.5 °C. Temperature had a significant effect on the time taken for the first individual to appear in the field of view. This time shortened with increasing temperature, regardless of protection level. This was likely a result of the metabolic constraints placed on individuals by low waters temperatures and individuals would be able to pursue the bait more readily at higher temperatures. However, there was no evidence of greater metabolic scope from the C. laticeps individuals observed in the MPAs, relative to the exploited areas. Individual size and the presence of conspecifics were also found to significantly influence behaviour. Generally, size had a positive relationship with behaviour, with larger individuals more likely to feed on the bait, chase other fish from the bait (only in the MPAs) and spend more time in the field of view. The higher displays of aggression in MPAs may be an indication of fishing practices having removed bold and dominant individuals at the exploited sites. The probability of fleeing and the feeding rates of individuals increased with increasing numbers of conspecifics, suggesting that C. laticeps behaviour is influenced by intraspecific competition. Overall, this thesis did not find strong evidence that C. laticeps from MPAs performed better than C. laticeps from exploited areas, even at low temperatures. Behavioural responses to temperature were highly variable across locations and this may be attributed to high behavioural phenotypic diversity among individuals. Environmental stressors, such as temperature changes, can illicit very different behavioural responses among individuals in a population. It is also possible that C. laticeps from the exploited areas have the same genetic predispositions to physiological stress as the individuals in the MPAs due to spillover and larval recruitment from the MPAs. Indeed, genetic studies find that all C. laticeps population in South African represent a single well-mixed genetic stock. It is likely that greater sampling effort is required to resolve the patterns in behaviour between exploited and protected populations. Nonetheless, given the influence of size on behaviour, the smaller size of C. laticeps at Port Elizabeth may be cause for concern regarding the vulnerability of future populations to ongoing climate change. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-04-06
Peer-to-peer energy trading system using IoT and a low-computation blockchain network
- Authors: Ncube, Tyron
- Date: 2021-10-29
- Subjects: Blockchains (Databases) , Internet of things , Renewable energy sources , Smart power grids , Peer-to-peer architecture (Computer networks) , Energy trading system
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192119 , vital:45197
- Description: The use of renewable energy is increasing every year as it is seen as a viable and sustain- able long-term alternative to fossil-based sources of power. Emerging technologies are being merged with existing renewable energy systems to address some of the challenges associated with renewable energy, such as reliability and limited storage facilities for the generated energy. The Internet of Things (IoT) has made it possible for consumers to make money by selling off excess energy back to the utility company through smart grids that allow bi-directional communication between the consumer and the utility company. The major drawback of this is that the utility company still plays a central role in this setup as they are the only buyer of this excess energy generated from renewable energy sources. This research intends to use blockchain technology by leveraging its decentralized architecture to enable other individuals to be able to purchase this excess energy. Blockchain technology is first explained in detail, and its main features, such as consensus mechanisms, are examined. This evaluation of blockchain technology gives rise to some design questions that are taken into consideration to create a low-energy, low-computation Ethereum-based blockchain network that is the foundation for a peer-to-peer energy trading system. The peer-to-peer energy trading system makes use of smart meters to collect data about energy usage and gives users a web-based interface where they can transact with each other. A smart contract is also designed to facilitate payments for transactions. Lastly, the system is tested by carrying out transactions and transferring energy from one node in the system to another. , Thesis (MSc) -- Faculty of Science, Computer Science, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Ncube, Tyron
- Date: 2021-10-29
- Subjects: Blockchains (Databases) , Internet of things , Renewable energy sources , Smart power grids , Peer-to-peer architecture (Computer networks) , Energy trading system
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192119 , vital:45197
- Description: The use of renewable energy is increasing every year as it is seen as a viable and sustain- able long-term alternative to fossil-based sources of power. Emerging technologies are being merged with existing renewable energy systems to address some of the challenges associated with renewable energy, such as reliability and limited storage facilities for the generated energy. The Internet of Things (IoT) has made it possible for consumers to make money by selling off excess energy back to the utility company through smart grids that allow bi-directional communication between the consumer and the utility company. The major drawback of this is that the utility company still plays a central role in this setup as they are the only buyer of this excess energy generated from renewable energy sources. This research intends to use blockchain technology by leveraging its decentralized architecture to enable other individuals to be able to purchase this excess energy. Blockchain technology is first explained in detail, and its main features, such as consensus mechanisms, are examined. This evaluation of blockchain technology gives rise to some design questions that are taken into consideration to create a low-energy, low-computation Ethereum-based blockchain network that is the foundation for a peer-to-peer energy trading system. The peer-to-peer energy trading system makes use of smart meters to collect data about energy usage and gives users a web-based interface where they can transact with each other. A smart contract is also designed to facilitate payments for transactions. Lastly, the system is tested by carrying out transactions and transferring energy from one node in the system to another. , Thesis (MSc) -- Faculty of Science, Computer Science, 2021
- Full Text:
- Date Issued: 2021-10-29
The physical activity status and the impact of lifestyle behaviours on workplace productivity and absenteeism of Transnet employees
- Authors: Zimmermann, Sharnae Vanessa
- Date: 2021-10
- Subjects: Transnet (Firm : South Africa) Employees , Absenteeism (Labor) South Africa Durban , Labor productivity South Africa Durban , Exercise , Sedentary behavior , Lifestyles
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190077 , vital:44961
- Description: Increased sitting time, insufficient physical activity and sub-optimal body composition are all contributing to the global disease burden. This is made evident by increases in obesity, type II diabetes, cardiovascular diseases (i.e. hypertension and strokes), cancer and other non-communicable diseases resulting in absenteeism and reduced productivity in the workplace. The global rise in sitting time and physical inactivity is caused, in part, by changes in transport convenience, work roles and technological advancements. Employees working in office environments or driving trains sit for prolonged periods; something which is evident in the industry that Transnet operates in. Sitting time and physical inactivity are independent risk factors for non-communicable diseases with poor nutrition, smoking, alcohol consumption and psychological wellbeing, being separate constructs. The purpose of the study is to determine the levels of sedentary behaviour, physical inactivity, obesity, nutrition, alcohol consumption, smoking, non-communicable disease risk, mental wellbeing and their association with productivity and absenteeism in office workers and train drivers at Transnet Freight Rail, Durban. A cross-sectional study was done with 40 participants, 20 office workers and 20 train drivers. Stature (175.80 ± 9.43 ±cm) and body mass (83.85 ± 20.31 kg) were measured; and body mass index calculated (26.98 ± 5.37 kg.m2). Physical activity levels, sedentary behaviour, body mass index and other lifestyle factors were explored using an amended version of The Health and Wellbeing survey, a self-report measure. The results revealed that there was a high prevalence of sedentary behaviour (train drivers = 7.85 ± 2.21 and office workers = 8.3 ± 1.03), particularly among office workers. Most of the participants had a relatively high body mass index, placing in the overweight and obese category, particularly among train drivers. The prevalence of physical inactivity was marginally higher for office workers compared to train drivers. There were significantly (p<0.05) higher levels of physical activity within train drivers with a moderate effect size. There were limited associations found between lifestyle factors and sickness absenteeism and worker productivity. Obesity had the most prominent relationship with noncommunicable diseases, followed by high levels of sedentary behaviour, not meeting physical activity guidelines, obesity, overweight, and prolonged sitting time at work. A significant and moderate correlation was found between obesity and absenteeism (train drivers: r = 0.32 and office workers: r= 0.46), however, no associations were found between sedentary behaviour, physical activity and fruit and vegetable intake and absenteeism. Lastly, the association between physical activity and productivity among the train drivers was low negative (r=-0.15) which was not significant (p>0.05). The associations between physical activity and productivity among office workers, however, was both significant (p<0.05) and moderate positive (r=0.39). The vegetable intake among the office workers showed a significant (p<0.05) moderate positive association with productivity (r=0.49). The association between vegetable intake and productivity among the train drivers was not significant (p>0.05) and low positive (r=0.16). There was a significant (p<0.05) and moderate positive association between fruit intake and productivity among both train drivers (r=0.43) and office workers (r=0.47). No significant associations between sedentary behaviour and obesity and productivity were found. The current study provided new insight into the risks associated with lifestyle factors of office workers and train drivers in the transportation sector. The poor lifestyle factors, together with the high prevalence of sedentary behaviour and physical inactivity, provide ideal opportunities for future interventions to focus on workers productivity and overall wellbeing. The job design of train drivers and office workers does not place significant importance on employee health and wellness. Essentially they are not “healthy” but they work productively, giving reason as to why employee wellness is not a priority for employers. The current findings of the study suggest that adopting regular physical activity, healthy dietary patterns and reduced sitting time should be promoted as key components of lifestyle interventions for the prevention of non-communicable diseases in office workers and train drivers. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Zimmermann, Sharnae Vanessa
- Date: 2021-10
- Subjects: Transnet (Firm : South Africa) Employees , Absenteeism (Labor) South Africa Durban , Labor productivity South Africa Durban , Exercise , Sedentary behavior , Lifestyles
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190077 , vital:44961
- Description: Increased sitting time, insufficient physical activity and sub-optimal body composition are all contributing to the global disease burden. This is made evident by increases in obesity, type II diabetes, cardiovascular diseases (i.e. hypertension and strokes), cancer and other non-communicable diseases resulting in absenteeism and reduced productivity in the workplace. The global rise in sitting time and physical inactivity is caused, in part, by changes in transport convenience, work roles and technological advancements. Employees working in office environments or driving trains sit for prolonged periods; something which is evident in the industry that Transnet operates in. Sitting time and physical inactivity are independent risk factors for non-communicable diseases with poor nutrition, smoking, alcohol consumption and psychological wellbeing, being separate constructs. The purpose of the study is to determine the levels of sedentary behaviour, physical inactivity, obesity, nutrition, alcohol consumption, smoking, non-communicable disease risk, mental wellbeing and their association with productivity and absenteeism in office workers and train drivers at Transnet Freight Rail, Durban. A cross-sectional study was done with 40 participants, 20 office workers and 20 train drivers. Stature (175.80 ± 9.43 ±cm) and body mass (83.85 ± 20.31 kg) were measured; and body mass index calculated (26.98 ± 5.37 kg.m2). Physical activity levels, sedentary behaviour, body mass index and other lifestyle factors were explored using an amended version of The Health and Wellbeing survey, a self-report measure. The results revealed that there was a high prevalence of sedentary behaviour (train drivers = 7.85 ± 2.21 and office workers = 8.3 ± 1.03), particularly among office workers. Most of the participants had a relatively high body mass index, placing in the overweight and obese category, particularly among train drivers. The prevalence of physical inactivity was marginally higher for office workers compared to train drivers. There were significantly (p<0.05) higher levels of physical activity within train drivers with a moderate effect size. There were limited associations found between lifestyle factors and sickness absenteeism and worker productivity. Obesity had the most prominent relationship with noncommunicable diseases, followed by high levels of sedentary behaviour, not meeting physical activity guidelines, obesity, overweight, and prolonged sitting time at work. A significant and moderate correlation was found between obesity and absenteeism (train drivers: r = 0.32 and office workers: r= 0.46), however, no associations were found between sedentary behaviour, physical activity and fruit and vegetable intake and absenteeism. Lastly, the association between physical activity and productivity among the train drivers was low negative (r=-0.15) which was not significant (p>0.05). The associations between physical activity and productivity among office workers, however, was both significant (p<0.05) and moderate positive (r=0.39). The vegetable intake among the office workers showed a significant (p<0.05) moderate positive association with productivity (r=0.49). The association between vegetable intake and productivity among the train drivers was not significant (p>0.05) and low positive (r=0.16). There was a significant (p<0.05) and moderate positive association between fruit intake and productivity among both train drivers (r=0.43) and office workers (r=0.47). No significant associations between sedentary behaviour and obesity and productivity were found. The current study provided new insight into the risks associated with lifestyle factors of office workers and train drivers in the transportation sector. The poor lifestyle factors, together with the high prevalence of sedentary behaviour and physical inactivity, provide ideal opportunities for future interventions to focus on workers productivity and overall wellbeing. The job design of train drivers and office workers does not place significant importance on employee health and wellness. Essentially they are not “healthy” but they work productively, giving reason as to why employee wellness is not a priority for employers. The current findings of the study suggest that adopting regular physical activity, healthy dietary patterns and reduced sitting time should be promoted as key components of lifestyle interventions for the prevention of non-communicable diseases in office workers and train drivers. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2021
- Full Text:
- Date Issued: 2021-10
Biology, ecology and management of the Keurboom moth, Leto venus Cramer and the leafhopper Molopopterus sp. Jacobi in cultivated Honeybush (Cyclopia spp.)
- Authors: Mushore, Tapiwa Gift
- Date: 2021-04
- Subjects: Legumes , Legumes -- Diseases and pests , Hepialidae , Leafhoppers , Pests -- Biological control , Entomopathogenic fungi , Leafhoppers -- Biological control , Hepialidae -- Biological control , Keurboom moth (Leto venus Cramer) , Molopopterus sp. Jacobi , Honeybush (Cyclopia spp.)
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177125 , vital:42792
- Description: Honeybush, Cyclopia spp. Vent (Fabaceae), farmers have raised pest concerns following commercial cultivation. The Keurboom moth Leto venus Cramer (Lepidoptera: Hepialidae) and the leafhopper Molopopterus sp. Jacobi (Hemiptera: Cicadellidae), are two of the major pests identified in cultivated Honeybush. Laboratory and field studies were conducted to gain an understanding of the biology of these two pests to inform future pest management solutions. Additionally, entomopathogenic fungi were isolated from Honeybush farms and screened for virulence against Molopopterus sp. as a possible management strategy. This study showed that the L. venus infestation on Honeybush was a product of four fixed effects; stem diameter, species of Cyclopia, Farm location and age of the plants. Cyclopia subternata, had the highest likelihood of infestation. Increase in age of the plants resulted in an increase in the stem diameter and therefore a higher probability of infestation. Stem diameter was also shown to be a significant predictor of infestation likelihood. Infestation severity, determined by the number of larvae per plant, was shown to be influenced by three fixed effects; stem diameter, plant species and Farm location. The results also showed that L. venus prefers to initiate penetration at, or just aboveground level. Laboratory studies showed that the leafhopper Molopopterus sp. undergoes five nymphal instars with an average egg incubation time of 20 days, development time from 1st instar to adult of 26 days and average generation time of 47 days. Laboratory experiments revealed variations in host preference by the leafhopper over a period of 15 days. Cyclopia longifolia was identified to be the most preferred species for feeding compared to the two other commonly cultivated species, C. subternata and C. maculata. The results were consistent with those obtained from the field survey which showed that leafhopper density was influenced by four fixed effects; plant species, age of the plant, Farm location and harvesting practices. There were significant differences in leafhopper density in different species with C. longifolia having the highest number of leafhoppers per plant. There were differences in leafhopper density in different farms as 57% of the sampled farms had leafhopper infestations, of these farms, Lodestone and Kurland had the highest leafhopper densities. Harvested plants were shown to have significantly higher leafhopper density than non-harvested plants. Age was also shown to influence leafhopper density, which reduced with an increase in the age of the plants. A total of 20 fungal isolates were recovered from 98 soil samples of which 70% were from Honeybush fields and 30% were from surrounding refugia. Fusarium oxysporum isolates comprised 20% of the recovered isolates, with Metarhizium anisopliae isolates making up the remainder. Laboratory bioassays against adults and nymphs of the leafhopper, Molopopterus sp., showed that F. oxysporum isolates induced 10 – 45% mortality and M. anisopliae isolates induce 30 – 80% mortality. Metarhizium anisopliae isolates J S1, KF S3, KF S11, KF S13, LS1 and LS2 were the most virulent and induced over 60% mortality in both Molopopterus sp. nymphs and adults. The results of this study showed pest preference towards different Cyclopia species. As such, they should be managed differently. Furthermore, L. venus was observed to occur in low densities, hence, it cannot be considered a major pest. However, Molopopterus sp. recorded high population densities making it a major pest in Honeybush production. Positive results indicated that some of the isolated fungal isolates have potential for control, an avenue worth investigating further. , Thesis (MSc) -- Faculty of Science, Department of Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Mushore, Tapiwa Gift
- Date: 2021-04
- Subjects: Legumes , Legumes -- Diseases and pests , Hepialidae , Leafhoppers , Pests -- Biological control , Entomopathogenic fungi , Leafhoppers -- Biological control , Hepialidae -- Biological control , Keurboom moth (Leto venus Cramer) , Molopopterus sp. Jacobi , Honeybush (Cyclopia spp.)
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177125 , vital:42792
- Description: Honeybush, Cyclopia spp. Vent (Fabaceae), farmers have raised pest concerns following commercial cultivation. The Keurboom moth Leto venus Cramer (Lepidoptera: Hepialidae) and the leafhopper Molopopterus sp. Jacobi (Hemiptera: Cicadellidae), are two of the major pests identified in cultivated Honeybush. Laboratory and field studies were conducted to gain an understanding of the biology of these two pests to inform future pest management solutions. Additionally, entomopathogenic fungi were isolated from Honeybush farms and screened for virulence against Molopopterus sp. as a possible management strategy. This study showed that the L. venus infestation on Honeybush was a product of four fixed effects; stem diameter, species of Cyclopia, Farm location and age of the plants. Cyclopia subternata, had the highest likelihood of infestation. Increase in age of the plants resulted in an increase in the stem diameter and therefore a higher probability of infestation. Stem diameter was also shown to be a significant predictor of infestation likelihood. Infestation severity, determined by the number of larvae per plant, was shown to be influenced by three fixed effects; stem diameter, plant species and Farm location. The results also showed that L. venus prefers to initiate penetration at, or just aboveground level. Laboratory studies showed that the leafhopper Molopopterus sp. undergoes five nymphal instars with an average egg incubation time of 20 days, development time from 1st instar to adult of 26 days and average generation time of 47 days. Laboratory experiments revealed variations in host preference by the leafhopper over a period of 15 days. Cyclopia longifolia was identified to be the most preferred species for feeding compared to the two other commonly cultivated species, C. subternata and C. maculata. The results were consistent with those obtained from the field survey which showed that leafhopper density was influenced by four fixed effects; plant species, age of the plant, Farm location and harvesting practices. There were significant differences in leafhopper density in different species with C. longifolia having the highest number of leafhoppers per plant. There were differences in leafhopper density in different farms as 57% of the sampled farms had leafhopper infestations, of these farms, Lodestone and Kurland had the highest leafhopper densities. Harvested plants were shown to have significantly higher leafhopper density than non-harvested plants. Age was also shown to influence leafhopper density, which reduced with an increase in the age of the plants. A total of 20 fungal isolates were recovered from 98 soil samples of which 70% were from Honeybush fields and 30% were from surrounding refugia. Fusarium oxysporum isolates comprised 20% of the recovered isolates, with Metarhizium anisopliae isolates making up the remainder. Laboratory bioassays against adults and nymphs of the leafhopper, Molopopterus sp., showed that F. oxysporum isolates induced 10 – 45% mortality and M. anisopliae isolates induce 30 – 80% mortality. Metarhizium anisopliae isolates J S1, KF S3, KF S11, KF S13, LS1 and LS2 were the most virulent and induced over 60% mortality in both Molopopterus sp. nymphs and adults. The results of this study showed pest preference towards different Cyclopia species. As such, they should be managed differently. Furthermore, L. venus was observed to occur in low densities, hence, it cannot be considered a major pest. However, Molopopterus sp. recorded high population densities making it a major pest in Honeybush production. Positive results indicated that some of the isolated fungal isolates have potential for control, an avenue worth investigating further. , Thesis (MSc) -- Faculty of Science, Department of Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-04
The physical activity levels and preferences of South African breast cancer survivors : a pilot study
- Authors: Campbell, Belinda Claire
- Date: 2021-04
- Subjects: Breast -- Cancer , Cancer -- Patients -- South Africa , Cancer -- Patients -- Rehabilitation , Exercise -- Health aspects , Godin leisure-time activity questionnaire (GLTPAQ) , International Physical Activity Questionnaire (IPAQ)
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177748 , vital:42855
- Description: Introduction: Breast cancer is currently the most commonly diagnosed cancer in South African women. Physical activity has proven to have preventative, treatment and management benefits for breast cancer and other cancers and exercise has been found as both viable and safe during cancer treatment and recovery. However, there is limited research on breast cancer and the levels and preferences of physical activity and sedentary behaviour in a South African context. Therefore, the purpose of this study was to identify levels of physical activity and sedentary behaviour of South African breast cancer survivors and to investigate the physical activity advice and participation preferences of these participants. Methods: A cross-sectional research design was implemented to identify the physical activity, sedentary behaviour levels and exercise preferences of 48 South African breast cancer survivors (age range 45 years). An online survey comprising demographic and anthropometric questions, the Godin leisure-time activity questionnaire (GLTPAQ), the International Physical Activity Questionnaire (IPAQ) and an exercise preference questionnaire was presented to participating breast cancer survivors in order to i) identify the levels of physical activity and sedentary behaviour engaged in, ii) obtain demographic and anthropometric information and iii) identify exercise preferences. A linear mixed model regression was used to examine potential associations between demographic and anthropometric variables and physical activity levels. Chi-squared and Pearson’s Product-Moment correlation tests were used to identify relationships between categorical and numerical variables. A correlation matrix was generated to further explore any correlations. Statistical significance for all measures was set at p<0.05. Results: The mean age of the group was 49 ± 9.87 years. The most common time since diagnosis was <5 years ago and the most common stage of breast cancer was stage I. The mean BMI was 27.87 ± 5.53kg/m2. The most common treatment combination was surgery with either chemotherapy or radiation. According to the leisure score index (LSI) the majority of the group (56%) was active and according to IPAQ data 60% were meeting physical activity guidelines. The highest physical activity levels were seen in the average weekly minutes of moderate-intensity activity, and there was a strong, non-significant positive correlation (p>0.05, R2 = 0.95) between moderate-intensity physical activity and total physical activity levels. High levels of weekly sedentary behaviour and sitting time (302.60 ± 169.96 minutes) were reported. A weak, non-significant, positive correlation was found between total sedentary time and BMI (p>0.05, R2 = 0.1). A weak, non-significant, negative correlation was found between age and sedentary time (p>0.05, R2 = 0.002). More participants below 50 years were insufficiently active compared to above the age of 50 years. 1.7 to 2.6 years since diagnosis saw the greatest number of insufficiently active survivors and the category over 2.6 years since diagnosis saw the most active survivors. Most breast cancer survivors (71.10% & 82.05%) indicated being interested in and feeling capable of participating in an exercise programme (p>0.05, R2 = 0.72). The favoured preference for receiving physical activity advice was face-to-face with an exercise specialist at a cancer centre before treatment. Participation preferences included starting a programme immediately after treatment, in a home-based setting with one or two other people, where walking and a moderate exercise intensity were the preferred exercise type and level of intensity. Data collection occurred both immediately prior to (42% of participants) and during (56% of participants) the South African Covid-19 lockdown, so the results should be seen in light of this context. Conclusion: The current study is one of the first to explore physical activity rates and preferences of South African breast cancer survivors. As a group and individually these survivors were meeting public physical activity guidelines and engaging in the recommended weekly minutes. The high sitting time coupled with the high overweight and obesity levels highlight the need for positive behavioural changes including improved levels of physical activity and reduced sedentary behaviour. These changes need involvement from the numerous levels of society that affect health. Broad physical activity guidelines need to be developed not only to improve physical activity levels in breast cancer survivors but to work as a preventative measure by facilitating physical activity promotion in the general population. The findings of this study demonstrate that this group of South African breast cancer survivors is open to physical activity advice, to programmes and to improving physical activity levels. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Campbell, Belinda Claire
- Date: 2021-04
- Subjects: Breast -- Cancer , Cancer -- Patients -- South Africa , Cancer -- Patients -- Rehabilitation , Exercise -- Health aspects , Godin leisure-time activity questionnaire (GLTPAQ) , International Physical Activity Questionnaire (IPAQ)
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177748 , vital:42855
- Description: Introduction: Breast cancer is currently the most commonly diagnosed cancer in South African women. Physical activity has proven to have preventative, treatment and management benefits for breast cancer and other cancers and exercise has been found as both viable and safe during cancer treatment and recovery. However, there is limited research on breast cancer and the levels and preferences of physical activity and sedentary behaviour in a South African context. Therefore, the purpose of this study was to identify levels of physical activity and sedentary behaviour of South African breast cancer survivors and to investigate the physical activity advice and participation preferences of these participants. Methods: A cross-sectional research design was implemented to identify the physical activity, sedentary behaviour levels and exercise preferences of 48 South African breast cancer survivors (age range 45 years). An online survey comprising demographic and anthropometric questions, the Godin leisure-time activity questionnaire (GLTPAQ), the International Physical Activity Questionnaire (IPAQ) and an exercise preference questionnaire was presented to participating breast cancer survivors in order to i) identify the levels of physical activity and sedentary behaviour engaged in, ii) obtain demographic and anthropometric information and iii) identify exercise preferences. A linear mixed model regression was used to examine potential associations between demographic and anthropometric variables and physical activity levels. Chi-squared and Pearson’s Product-Moment correlation tests were used to identify relationships between categorical and numerical variables. A correlation matrix was generated to further explore any correlations. Statistical significance for all measures was set at p<0.05. Results: The mean age of the group was 49 ± 9.87 years. The most common time since diagnosis was <5 years ago and the most common stage of breast cancer was stage I. The mean BMI was 27.87 ± 5.53kg/m2. The most common treatment combination was surgery with either chemotherapy or radiation. According to the leisure score index (LSI) the majority of the group (56%) was active and according to IPAQ data 60% were meeting physical activity guidelines. The highest physical activity levels were seen in the average weekly minutes of moderate-intensity activity, and there was a strong, non-significant positive correlation (p>0.05, R2 = 0.95) between moderate-intensity physical activity and total physical activity levels. High levels of weekly sedentary behaviour and sitting time (302.60 ± 169.96 minutes) were reported. A weak, non-significant, positive correlation was found between total sedentary time and BMI (p>0.05, R2 = 0.1). A weak, non-significant, negative correlation was found between age and sedentary time (p>0.05, R2 = 0.002). More participants below 50 years were insufficiently active compared to above the age of 50 years. 1.7 to 2.6 years since diagnosis saw the greatest number of insufficiently active survivors and the category over 2.6 years since diagnosis saw the most active survivors. Most breast cancer survivors (71.10% & 82.05%) indicated being interested in and feeling capable of participating in an exercise programme (p>0.05, R2 = 0.72). The favoured preference for receiving physical activity advice was face-to-face with an exercise specialist at a cancer centre before treatment. Participation preferences included starting a programme immediately after treatment, in a home-based setting with one or two other people, where walking and a moderate exercise intensity were the preferred exercise type and level of intensity. Data collection occurred both immediately prior to (42% of participants) and during (56% of participants) the South African Covid-19 lockdown, so the results should be seen in light of this context. Conclusion: The current study is one of the first to explore physical activity rates and preferences of South African breast cancer survivors. As a group and individually these survivors were meeting public physical activity guidelines and engaging in the recommended weekly minutes. The high sitting time coupled with the high overweight and obesity levels highlight the need for positive behavioural changes including improved levels of physical activity and reduced sedentary behaviour. These changes need involvement from the numerous levels of society that affect health. Broad physical activity guidelines need to be developed not only to improve physical activity levels in breast cancer survivors but to work as a preventative measure by facilitating physical activity promotion in the general population. The findings of this study demonstrate that this group of South African breast cancer survivors is open to physical activity advice, to programmes and to improving physical activity levels. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2021
- Full Text:
- Date Issued: 2021-04
The role of the Hop co-chaperone in the formation of Hsp90 complexes: chaperone link to glycolysis
- Authors: Maharaj, Shantal
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163593 , vital:41051 , doi:10.21504/10962/163593
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
- Authors: Maharaj, Shantal
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163593 , vital:41051 , doi:10.21504/10962/163593
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
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