Caregivers’ and parents’ views about preschool education as a school readiness programme in the Queenstown Education District
- Mtyuda, Pamela Nomonde Pettina
- Authors: Mtyuda, Pamela Nomonde Pettina
- Date: 2019
- Subjects: Education, Preschool Readiness for school
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/16166 , vital:40674
- Description: The aim of this study was to uncover preschool caregivers’ and parents’ views about preschool education as a preschool readiness programme in the Queenstown education district. The research study addressed the following specific objectives, to determine: the caregivers’ and parents’ understanding of school readiness nature of preschool education; the extent to which the caregivers’ practices can make children ready for formal schooling; the parents’ assessment of the preschool centres as places that make children ready for formal schooling; caregivers’ and parents’ views on the challenges facing preschool centres against making children ready for formal schooling; and lastly, the possible solutions to the challenges facing preschool centres. In the present study, both qualitative and quantitative data were collected. Quantitative data were gathered through questionnaires from 40 preschool caregivers at preschools and 40 parents of the children in those preschools that were chosen by the caregivers on the basis of parents who are highly committed in the education of their children. The qualitative data were gathered through focus group discussions with 2 focus groups located in the Queenstown Education district. Twelve participants were interviewed, and these comprised 6 caregivers that formed the focus group discussion 1 and 6 parents that formed the focus group discussion 2, using the interview schedules as guides. Purposive sampling to select the participants was used. Triangulation design was used to gather both quantitative and qualitative data at the same time and to integrate the two forms of data in order to have a better understanding of the research objectives. The research findings indicated that the most frequently reported issues by the participants were the problems with some caregivers who had limited knowledge to make children ready for formal schooling. Some of the parents and caregivers do not understand the importance of the domains of development in making children fully ready for formal schooling. There is still lack of parental involvement in those centres; no effective communication between parents and staff; caregivers are not aware of the policies that govern the preschools; poverty and unemployment are factors that inhibit the right of young children to education; no proper resources in preschools and the unregistered preschools also still need to be helped by coordinated efforts from communities and the government bodies. It was concluded that the quality of early childhood development(ECD) programmes in Queenstown preschools was still compromised. The study recommended extensive investment in infrastructure and learning and teaching support materials is necessary; there should be sufficient staffing with ECD expertise; programmes should be designed in order to educate and encourage parents to actively involve themselves with preschool activities.
- Full Text:
- Date Issued: 2019
- Authors: Mtyuda, Pamela Nomonde Pettina
- Date: 2019
- Subjects: Education, Preschool Readiness for school
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/16166 , vital:40674
- Description: The aim of this study was to uncover preschool caregivers’ and parents’ views about preschool education as a preschool readiness programme in the Queenstown education district. The research study addressed the following specific objectives, to determine: the caregivers’ and parents’ understanding of school readiness nature of preschool education; the extent to which the caregivers’ practices can make children ready for formal schooling; the parents’ assessment of the preschool centres as places that make children ready for formal schooling; caregivers’ and parents’ views on the challenges facing preschool centres against making children ready for formal schooling; and lastly, the possible solutions to the challenges facing preschool centres. In the present study, both qualitative and quantitative data were collected. Quantitative data were gathered through questionnaires from 40 preschool caregivers at preschools and 40 parents of the children in those preschools that were chosen by the caregivers on the basis of parents who are highly committed in the education of their children. The qualitative data were gathered through focus group discussions with 2 focus groups located in the Queenstown Education district. Twelve participants were interviewed, and these comprised 6 caregivers that formed the focus group discussion 1 and 6 parents that formed the focus group discussion 2, using the interview schedules as guides. Purposive sampling to select the participants was used. Triangulation design was used to gather both quantitative and qualitative data at the same time and to integrate the two forms of data in order to have a better understanding of the research objectives. The research findings indicated that the most frequently reported issues by the participants were the problems with some caregivers who had limited knowledge to make children ready for formal schooling. Some of the parents and caregivers do not understand the importance of the domains of development in making children fully ready for formal schooling. There is still lack of parental involvement in those centres; no effective communication between parents and staff; caregivers are not aware of the policies that govern the preschools; poverty and unemployment are factors that inhibit the right of young children to education; no proper resources in preschools and the unregistered preschools also still need to be helped by coordinated efforts from communities and the government bodies. It was concluded that the quality of early childhood development(ECD) programmes in Queenstown preschools was still compromised. The study recommended extensive investment in infrastructure and learning and teaching support materials is necessary; there should be sufficient staffing with ECD expertise; programmes should be designed in order to educate and encourage parents to actively involve themselves with preschool activities.
- Full Text:
- Date Issued: 2019
Influence of trans-border trading activities on senior secondary school students' academic performance in economics in Ogun State, Nigeria
- Authors: Titus, Adesegun Benedict
- Date: 2018
- Subjects: Smuggling -- Education (Secondary) Borderlands -- Nigeria
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9659 , vital:34814
- Description: The study investigated the influence of transborder trading activities on senior secondary school students’ academic performance in economics in Ogun state, Nigeria. A descriptive survey research design involving 320 students that comprised males and females were selected through stratified random sampling technique. Two self-developed instruments were used: student questionnaire on transborder trading activities (SQTTA) with a Cronbach alpha index of 0.7845; and the economics achievement test (EAT) with a co-efficient index of r= 0.814. The results of the data collected were collated, coded, analyzed and interpreted through the use of descriptive research statistics of frequency, mean, percentages, and standard deviation while Step-wise regression analysis was used to test the hypotheses raised in the study, and the inferential statistics t-test was used to test the significant differences between the independent and dependent variables. The results revealed that there is a positive significant influence of smuggling on students’ academic performance in economics concepts (t=4.123; df =307, p<0.05) and a negative significant influence of school location on students’ academic performance in economics concepts (t=0.952; df=307, p>0.05). The study revealed that the most prevalent transborder trading activities like smuggling of used tyres, small firearms and fairly used clothes had negative influence on students’ academic performance. Based on these findings, discussions were focused on the involvement of students in trans-border trading activities and the location of schools, amongst others, which has no significant influence on students’ academic performance. However, it was recommended that schools should not be located near border areas in future.
- Full Text:
- Date Issued: 2018
- Authors: Titus, Adesegun Benedict
- Date: 2018
- Subjects: Smuggling -- Education (Secondary) Borderlands -- Nigeria
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9659 , vital:34814
- Description: The study investigated the influence of transborder trading activities on senior secondary school students’ academic performance in economics in Ogun state, Nigeria. A descriptive survey research design involving 320 students that comprised males and females were selected through stratified random sampling technique. Two self-developed instruments were used: student questionnaire on transborder trading activities (SQTTA) with a Cronbach alpha index of 0.7845; and the economics achievement test (EAT) with a co-efficient index of r= 0.814. The results of the data collected were collated, coded, analyzed and interpreted through the use of descriptive research statistics of frequency, mean, percentages, and standard deviation while Step-wise regression analysis was used to test the hypotheses raised in the study, and the inferential statistics t-test was used to test the significant differences between the independent and dependent variables. The results revealed that there is a positive significant influence of smuggling on students’ academic performance in economics concepts (t=4.123; df =307, p<0.05) and a negative significant influence of school location on students’ academic performance in economics concepts (t=0.952; df=307, p>0.05). The study revealed that the most prevalent transborder trading activities like smuggling of used tyres, small firearms and fairly used clothes had negative influence on students’ academic performance. Based on these findings, discussions were focused on the involvement of students in trans-border trading activities and the location of schools, amongst others, which has no significant influence on students’ academic performance. However, it was recommended that schools should not be located near border areas in future.
- Full Text:
- Date Issued: 2018
Implementation of gender policies to promote gender parity in leadership in academia : a case study of two universities in Bindura Urban Mashonaland Central Province Zimbabwe
- Authors: Mandoga, Edward
- Date: 2017
- Subjects: Women in higher education -- Zimbabwe Education, Higher -- Zimbabwe Sex discrimination in higher education -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/5260 , vital:29178
- Description: The study is premised on the assumptions that the under-representation of women in leadership in academia is aggravated by weak implementation of gender policies. In light of this, the aim of the current study was to assess the nature and extent of the implementation of gender policy frameworks as a way of engendering gender parity in leadership in academia. The study was informed by the socialist-feminist theory and John Rawls’ and David Millers’ theory of social justice. The theories were chosen on the basis of their socialist-scientific approach to gender issues and also because of their resonance with the situation in Zimbabwe’s tertiary institutions. The theories were analysed within the context of Agenda 2063. The relevance of the agenda’s vision for this study is its recognition of gender equality, particularly in leadership in academia, as a critical cog for Africa’s development agenda. The researcher opted to use the qualitative approach which is embedded within the interpretivist research paradigm. The interpretivist approach makes use of qualitative methods of data collection, presentation and analysis. Data were generated from a sample of twenty four lecturers, two vice-chancellors, two pro-vice-chancellors and two registrars from two universities, a private church-run institution and a state university, mainly through interviews. Data were also generated through focus group discussions and document analysis. Data from documents were used to buttress data from the interviews and focus group discussions. The findings of this study showed that the male-management norm dominated in almost every strategic section of the structures of the two institutions. This was attributable to weak implementation of gender policies. The failure of the gender policies to bring a visible change to the institutional landscape in terms of gender equality was a result of an interplay of personal, cultural and organisational factors. Some of the factors that thwarted women’s career progression to leadership positions included, lack of inspiration from role models, lack of support from colleagues, lack of training in leadership, and the Zimbabwe Council of Higher Education’s (ZIMCHE) indiscriminate policy on recruitment of staff members. All the factors however, were encapsulated within the patriarchal stereotypical conception of a women as fit for domesticity. Within the same conception, men were considered to be imbued with the clout and traits consistent with leadership demands. Studies carried out elsewhere in Zimbabwe and outside the boarders of Zimbabwe have yielded similar results. This explains the continuing and relentless nature of gender inequality in academic institutions. In order to increase the participation of women in leadership positions, the study recommends the following: establishment of a monitoring and evaluation exercise designed to audit the effectiveness of the gender policies; establishment of a review of the university programmes with the aim of establishing or intensifying training programmes in academic leadership and management; establishment of a scholarship and research fund to encourage women to undertake higher degrees studies, and the intense application of affirmative action policies and gender mainstreaming in the universities.
- Full Text:
- Date Issued: 2017
- Authors: Mandoga, Edward
- Date: 2017
- Subjects: Women in higher education -- Zimbabwe Education, Higher -- Zimbabwe Sex discrimination in higher education -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/5260 , vital:29178
- Description: The study is premised on the assumptions that the under-representation of women in leadership in academia is aggravated by weak implementation of gender policies. In light of this, the aim of the current study was to assess the nature and extent of the implementation of gender policy frameworks as a way of engendering gender parity in leadership in academia. The study was informed by the socialist-feminist theory and John Rawls’ and David Millers’ theory of social justice. The theories were chosen on the basis of their socialist-scientific approach to gender issues and also because of their resonance with the situation in Zimbabwe’s tertiary institutions. The theories were analysed within the context of Agenda 2063. The relevance of the agenda’s vision for this study is its recognition of gender equality, particularly in leadership in academia, as a critical cog for Africa’s development agenda. The researcher opted to use the qualitative approach which is embedded within the interpretivist research paradigm. The interpretivist approach makes use of qualitative methods of data collection, presentation and analysis. Data were generated from a sample of twenty four lecturers, two vice-chancellors, two pro-vice-chancellors and two registrars from two universities, a private church-run institution and a state university, mainly through interviews. Data were also generated through focus group discussions and document analysis. Data from documents were used to buttress data from the interviews and focus group discussions. The findings of this study showed that the male-management norm dominated in almost every strategic section of the structures of the two institutions. This was attributable to weak implementation of gender policies. The failure of the gender policies to bring a visible change to the institutional landscape in terms of gender equality was a result of an interplay of personal, cultural and organisational factors. Some of the factors that thwarted women’s career progression to leadership positions included, lack of inspiration from role models, lack of support from colleagues, lack of training in leadership, and the Zimbabwe Council of Higher Education’s (ZIMCHE) indiscriminate policy on recruitment of staff members. All the factors however, were encapsulated within the patriarchal stereotypical conception of a women as fit for domesticity. Within the same conception, men were considered to be imbued with the clout and traits consistent with leadership demands. Studies carried out elsewhere in Zimbabwe and outside the boarders of Zimbabwe have yielded similar results. This explains the continuing and relentless nature of gender inequality in academic institutions. In order to increase the participation of women in leadership positions, the study recommends the following: establishment of a monitoring and evaluation exercise designed to audit the effectiveness of the gender policies; establishment of a review of the university programmes with the aim of establishing or intensifying training programmes in academic leadership and management; establishment of a scholarship and research fund to encourage women to undertake higher degrees studies, and the intense application of affirmative action policies and gender mainstreaming in the universities.
- Full Text:
- Date Issued: 2017
Epistemological access in a science foundation course: a social realist perspective
- Authors: Ellery, Karen
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1335 , http://hdl.handle.net/10962/d1021309
- Description: This dissertation examines how educational practices of a multidisciplinary, integrated science foundation course, Introduction to Science Concepts and Methods (ISCM), at Rhodes University in South Africa, enable and/or constrain epistemological access to a range of mainstream science disciplines. Students in the ISCM course are mainly African, working-class, first-generation higher education learners whose home language is seldom English. This study is motivated firstly by poor success of working-class African students in higher education in South Africa in general and in the sciences in particular, and secondly by the need for closely theorised, empirical work to guide necessary transformational change that will contribute to equity and, thus, to greater social justice. Since I teach in ISCM and coordinate the programme in which it is located, I also have a personal and professional interest in improving my own practice. Conceptually the study draws on Morrow’s (2007, 2009) and various literacy theorists interpretations of the concept of epistemological access, which in this study is about becoming and being a participant in an academic practice by virtue of learning both the knowledge as well as the norms, values and beliefs that constitute the practice. Theoretically and analytically the study draws on Maton’s (2014a) Legitimation Code Theory (LCT) and on various aspects of Bernstein’s (2000) code theory work. Codes are the organising principles or ‘rules of the game’ of practices and code theory is premised on the idea that power and control in education systems manifest themselves through the structural and interactional aspects of educational practices, and therefore have the capacity to include or exclude. Analysing educational practices using code theory enables characterisation of the practices, highlights their underpinning principles, and allows for their effects to be considered. This layered approach to analysis indicates that a critical realist depth ontology serves as an underlabourer to code theory. The desired ‘effect’ of educational practices in this study, is students gaining epistemological access to science, or science disciplines, in higher education. The overall approach is a single, in-depth, qualitative case study with a primary focus on what is legitimated in ISCM educational practices (curriculum, pedagogy, assessment) and how students respond to these practices. A lesser focus is how ex-ISCM students are responding to educational practices in the first-year, first-semester Cell Biology, Chemistry, Earth Sciences and Physics mainstream courses, and whether they are attaining epistemological access. To examine educational practices in ISCM and mainstream courses data from document analysis, interviews, observations and critical reflections are analysed through developing external languages of description. The two LCT code dimensions of Specialisation (what or who specialises a practice) and Semantics (how meaning relates to context and empirical referents) are used to examine curriculum, Bernstein’s (2000) framing of the regulative and instructional discourses are drawn on in considering pedagogy, and an adapted cognitive process level model assists in analysing assessment practices. To examine student responses to educational practices Bernstein’s (ibid.) concept of acquisition of recognition and realisation rules is used. Since ISCM serves the dual purpose of developing scientific conceptual knowledge, as well as supporting student learning in an academic context, a complex picture of practices and underpinning codes emerges. Based on epistemological concerns of developing students as scientists, ISCM legitimates an epistemic-context knowledge code and a rhizomatic/worldly curriculum code. If students produce the legitimated epistemic-context scientific ‘text’, they have attained epistemic access. Based on axiological concerns of the learning context, ISCM also legitimates a learning-context knower code. By producing the legitimate learning-context ‘text’ of an autonomous, self-regulated science learner, students demonstrate they have attained learning-context access. Both forms of access are key for student success, and combined they constitute epistemological access. The findings of the study indicate that framing and legitimation of educational practices in ISCM, by most accounts, should be promoting epistemological access. When epistemological access is not attained in ISCM it is suggested this is likely due to both a code clash at the learning-context level and competing code demands between epistemic-context and learning-context concerns. Poor access in mainstream courses appears to be exacerbated by both a narrow-based knowledge code and little or no support for a learning-context knower code. The study concludes by outlining a two-tiered conceptual model of epistemological access in the sciences based on the mutually integrative components of epistemic- and learning-context access. Because of inequitable outcomes in science mainstream courses at Rhodes University based on race and/or class I argue for far-reaching transformative pedagogies throughout the faculty, and in the broader South African science higher education sector, that address and accommodate issues of diversity and difference. This should include, amongst other things, a weakening of epistemic relations to create space for a strengthening of learning-context social relations. This is not a suggestion to move away from a science knowledge code, which I argue is based on powerful knowledge to which all students must gain access, but instead a shift in emphasis to better support previously educationally disenfranchised students and to understand in a more rigorous manner what epistemological access means to them as individuals. In light of the recent disruptive and angry student calls for decolonisation of the curriculum, this is an urgent imperative.
- Full Text:
- Date Issued: 2016
- Authors: Ellery, Karen
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1335 , http://hdl.handle.net/10962/d1021309
- Description: This dissertation examines how educational practices of a multidisciplinary, integrated science foundation course, Introduction to Science Concepts and Methods (ISCM), at Rhodes University in South Africa, enable and/or constrain epistemological access to a range of mainstream science disciplines. Students in the ISCM course are mainly African, working-class, first-generation higher education learners whose home language is seldom English. This study is motivated firstly by poor success of working-class African students in higher education in South Africa in general and in the sciences in particular, and secondly by the need for closely theorised, empirical work to guide necessary transformational change that will contribute to equity and, thus, to greater social justice. Since I teach in ISCM and coordinate the programme in which it is located, I also have a personal and professional interest in improving my own practice. Conceptually the study draws on Morrow’s (2007, 2009) and various literacy theorists interpretations of the concept of epistemological access, which in this study is about becoming and being a participant in an academic practice by virtue of learning both the knowledge as well as the norms, values and beliefs that constitute the practice. Theoretically and analytically the study draws on Maton’s (2014a) Legitimation Code Theory (LCT) and on various aspects of Bernstein’s (2000) code theory work. Codes are the organising principles or ‘rules of the game’ of practices and code theory is premised on the idea that power and control in education systems manifest themselves through the structural and interactional aspects of educational practices, and therefore have the capacity to include or exclude. Analysing educational practices using code theory enables characterisation of the practices, highlights their underpinning principles, and allows for their effects to be considered. This layered approach to analysis indicates that a critical realist depth ontology serves as an underlabourer to code theory. The desired ‘effect’ of educational practices in this study, is students gaining epistemological access to science, or science disciplines, in higher education. The overall approach is a single, in-depth, qualitative case study with a primary focus on what is legitimated in ISCM educational practices (curriculum, pedagogy, assessment) and how students respond to these practices. A lesser focus is how ex-ISCM students are responding to educational practices in the first-year, first-semester Cell Biology, Chemistry, Earth Sciences and Physics mainstream courses, and whether they are attaining epistemological access. To examine educational practices in ISCM and mainstream courses data from document analysis, interviews, observations and critical reflections are analysed through developing external languages of description. The two LCT code dimensions of Specialisation (what or who specialises a practice) and Semantics (how meaning relates to context and empirical referents) are used to examine curriculum, Bernstein’s (2000) framing of the regulative and instructional discourses are drawn on in considering pedagogy, and an adapted cognitive process level model assists in analysing assessment practices. To examine student responses to educational practices Bernstein’s (ibid.) concept of acquisition of recognition and realisation rules is used. Since ISCM serves the dual purpose of developing scientific conceptual knowledge, as well as supporting student learning in an academic context, a complex picture of practices and underpinning codes emerges. Based on epistemological concerns of developing students as scientists, ISCM legitimates an epistemic-context knowledge code and a rhizomatic/worldly curriculum code. If students produce the legitimated epistemic-context scientific ‘text’, they have attained epistemic access. Based on axiological concerns of the learning context, ISCM also legitimates a learning-context knower code. By producing the legitimate learning-context ‘text’ of an autonomous, self-regulated science learner, students demonstrate they have attained learning-context access. Both forms of access are key for student success, and combined they constitute epistemological access. The findings of the study indicate that framing and legitimation of educational practices in ISCM, by most accounts, should be promoting epistemological access. When epistemological access is not attained in ISCM it is suggested this is likely due to both a code clash at the learning-context level and competing code demands between epistemic-context and learning-context concerns. Poor access in mainstream courses appears to be exacerbated by both a narrow-based knowledge code and little or no support for a learning-context knower code. The study concludes by outlining a two-tiered conceptual model of epistemological access in the sciences based on the mutually integrative components of epistemic- and learning-context access. Because of inequitable outcomes in science mainstream courses at Rhodes University based on race and/or class I argue for far-reaching transformative pedagogies throughout the faculty, and in the broader South African science higher education sector, that address and accommodate issues of diversity and difference. This should include, amongst other things, a weakening of epistemic relations to create space for a strengthening of learning-context social relations. This is not a suggestion to move away from a science knowledge code, which I argue is based on powerful knowledge to which all students must gain access, but instead a shift in emphasis to better support previously educationally disenfranchised students and to understand in a more rigorous manner what epistemological access means to them as individuals. In light of the recent disruptive and angry student calls for decolonisation of the curriculum, this is an urgent imperative.
- Full Text:
- Date Issued: 2016
The efficacy of a community based eccentric hamstring strengthening program in peri-urban Black South African soccer players
- Authors: Ryan, Bennett
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3573 , vital:20526
- Description: Introduction: Hamstring injury prevalence in soccer remains a major concern. Research in this context has focused on Caucasian populations with little attention given to other ethnic groups. The compatibility and applicability of such research to the South African context, particularly at an amateur level, may be minimal due to fundamental differences in physical characteristics, as well as complexities with regards to implementation. The aim of this investigation was therefore twofold. 1) Identify the lower extremity strength and performance profile of Peri-urban Amateur South African Players, and 2) Assess the efficacy of a community based intervention through the use of the Nordic Hamstring Exercise. Methods: 19 Black male Eastern Cape amateur players participated in a 12 week randomly controlled trial (9 = Control, 10 = Intervention). All participants completed regular training, while the intervention group, in addition, performed the Nordic Hamstring exercise post warm up. The incremental program design was taken from Mjolsnes et al. (2004), with a progressive increase in both sets and repetitions. Compliance was defined as completion of the required exercises for that session. Isokinetic strength evaluations (at 60°.s-1 and 180°.s-1) including assessment of peak torque and total work, as well as performance measures of countermovement and squat jump, were completed pre and post intervention, with the profile of the Peri-urban player the combined responses of both groups at baseline. Additionally, both the functional ratio (Eccentric Hamstrings/Concentric Quadriceps) and eccentric utilization ratio (Countermovement Jump/Squat Jump) were calculated. Results: Concentric quadriceps peak torque at baseline reported values of 195 (±22) Nm and 141 (±21) Nm at 60°.s-1 and 180°.s-1. Values of 162 (±21) Nm were observed for peak torque of the eccentric hamstrings at 60°.s-1, while 157 (±18) Nm was indicated at 180°.s-1. Mean functional ratio responses were observed as 0.83 (±0.11) and 1.12 (±0.16) for 60°.s-1 and 180°.s-1 respectively. Additionally, the eccentric utilization ratio responses were recorded as 1.04 (±0.08). Regarding the intervention, concentric quadriceps total work of the dominant limb significantly improved over the time course of experimentation within the intervention group. Other quadriceps variables, concentric hamstrings, squat jump capability and performance measures all reported no significant changes (p>0.05) over the course of assessment when compared to the control. Eccentric hamstrings peak torque observed significant improvements (p<0.05) of between 5.72 and 12.82 % within the intervention group, while the countermovement jump indicated a significant 15.59 % increase (p<0.05). Additionally, the functional ratio and the eccentric utilization ratio both indicated no significant changes (p>0.05), with a 2.48-7.66 % and 5.33 % improvement noted following completion of assessment. Conclusion: Isokinetic responses at baseline observed decreased quadriceps strength, and increased hamstring strength when compared to both amateur and professional populations examined in previous studies, for both isokinetic testing speeds. Additionally, performance measures indicated similar responses to other amateur populations. Regarding the intervention, significant improvements in eccentric hamstring peak torque and countermovement jump indicate the partial success of the present intervention. Additionally, while the functional ratio and eccentric utilization ratio reported no significant changes, improvements were noted within the intervention group while the control noted no change. The Nordic hamstring lower therefore resulted in strength improvements within the eccentric hamstrings, reported as a significant factor for injury risk, however, such changes were not sufficient to significantly impact the functional ratio. It can be concluded that community based programs within South Africa have the potential to be effective; however, there are many barriers to implementation, including, language, ethnic and cultural differences, while a lack of resources and infrastructure play a significant role in a lack of development. More research of this nature is required to provide scientific support for structures and guidelines for the peri-urban community based South African player, to ensure the efficacy of internationally successful interventions such as the Nordic exercise.
- Full Text:
- Date Issued: 2016
- Authors: Ryan, Bennett
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3573 , vital:20526
- Description: Introduction: Hamstring injury prevalence in soccer remains a major concern. Research in this context has focused on Caucasian populations with little attention given to other ethnic groups. The compatibility and applicability of such research to the South African context, particularly at an amateur level, may be minimal due to fundamental differences in physical characteristics, as well as complexities with regards to implementation. The aim of this investigation was therefore twofold. 1) Identify the lower extremity strength and performance profile of Peri-urban Amateur South African Players, and 2) Assess the efficacy of a community based intervention through the use of the Nordic Hamstring Exercise. Methods: 19 Black male Eastern Cape amateur players participated in a 12 week randomly controlled trial (9 = Control, 10 = Intervention). All participants completed regular training, while the intervention group, in addition, performed the Nordic Hamstring exercise post warm up. The incremental program design was taken from Mjolsnes et al. (2004), with a progressive increase in both sets and repetitions. Compliance was defined as completion of the required exercises for that session. Isokinetic strength evaluations (at 60°.s-1 and 180°.s-1) including assessment of peak torque and total work, as well as performance measures of countermovement and squat jump, were completed pre and post intervention, with the profile of the Peri-urban player the combined responses of both groups at baseline. Additionally, both the functional ratio (Eccentric Hamstrings/Concentric Quadriceps) and eccentric utilization ratio (Countermovement Jump/Squat Jump) were calculated. Results: Concentric quadriceps peak torque at baseline reported values of 195 (±22) Nm and 141 (±21) Nm at 60°.s-1 and 180°.s-1. Values of 162 (±21) Nm were observed for peak torque of the eccentric hamstrings at 60°.s-1, while 157 (±18) Nm was indicated at 180°.s-1. Mean functional ratio responses were observed as 0.83 (±0.11) and 1.12 (±0.16) for 60°.s-1 and 180°.s-1 respectively. Additionally, the eccentric utilization ratio responses were recorded as 1.04 (±0.08). Regarding the intervention, concentric quadriceps total work of the dominant limb significantly improved over the time course of experimentation within the intervention group. Other quadriceps variables, concentric hamstrings, squat jump capability and performance measures all reported no significant changes (p>0.05) over the course of assessment when compared to the control. Eccentric hamstrings peak torque observed significant improvements (p<0.05) of between 5.72 and 12.82 % within the intervention group, while the countermovement jump indicated a significant 15.59 % increase (p<0.05). Additionally, the functional ratio and the eccentric utilization ratio both indicated no significant changes (p>0.05), with a 2.48-7.66 % and 5.33 % improvement noted following completion of assessment. Conclusion: Isokinetic responses at baseline observed decreased quadriceps strength, and increased hamstring strength when compared to both amateur and professional populations examined in previous studies, for both isokinetic testing speeds. Additionally, performance measures indicated similar responses to other amateur populations. Regarding the intervention, significant improvements in eccentric hamstring peak torque and countermovement jump indicate the partial success of the present intervention. Additionally, while the functional ratio and eccentric utilization ratio reported no significant changes, improvements were noted within the intervention group while the control noted no change. The Nordic hamstring lower therefore resulted in strength improvements within the eccentric hamstrings, reported as a significant factor for injury risk, however, such changes were not sufficient to significantly impact the functional ratio. It can be concluded that community based programs within South Africa have the potential to be effective; however, there are many barriers to implementation, including, language, ethnic and cultural differences, while a lack of resources and infrastructure play a significant role in a lack of development. More research of this nature is required to provide scientific support for structures and guidelines for the peri-urban community based South African player, to ensure the efficacy of internationally successful interventions such as the Nordic exercise.
- Full Text:
- Date Issued: 2016
Surface properties and electrocatalytic applications of metallophthalocyanines confined on electrode surfaces
- Authors: Akinbulu, Isaac Adebayo
- Date: 2011
- Subjects: Phthalocyanines Electrochemistry Electrocatalysis Pesticides
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4365 , http://hdl.handle.net/10962/d1005030
- Description: New cobalt (13, 16 19 and 22), manganese (14, 17, 20 and 23) and iron (15, 18, 21 and 24)phthalocyanine complexes were synthesized and characterized. The UV-Vis spectral properties of the complexes were typical of the nature of central metal and position of substituent on the Pc ligand. Their electrochemical behaviors were signatures of the central metals, with varying influences of the nature and position of substituents. Nanocomposite of complex 18 and single walled carbon nanotubes (SWCNTs) (SWCNT-18)was fabricated. Formation of this nano-composite was confirmed by infrared (IR)spectroscopy, X-ray diffraction (XRD) spectroscopy and transmission electron microscopy (TEM). Self-assembled monolayers (SAMs) of SWCNT-18, complexes 13-15, and 20 were electropolymerized on glassy carbon electrodes (GCE). Complex 14 was also electrodeposited on GCE. Surface properties of the SAMs were consistent with the molecular feature of the substituent and the nature of central metal in the adsorbed species, while those of the MnPc modified GCEs were dependent on point of substitution and number of substituent. The SAM-modified gold electrodes were used for the electrocatalytic oxidation of the carbamate insecticide, carbofuran. Amplification of the current signal of the insecticide, at more energetically feasible oxidation potentials, on the SAM-modified gold electrodes, relative to bare gold electrode,justified electrocatalysis. There was enhanced sensitivity (attributed to the presence of SWCNT) of the SWCNT-18-SAM-modified gold electrode towards carbofuran, relative to the signals observed on the other SAMs. Current response of the insecticide,bendiocarb, was also intensified, at more favorable oxidation potentials, on the MnPc (14 and 17) modified GCEs, relative to the response on bare GCE, substantiating electrocatalysis. Also, catalysis of the oxidation of the herbicide, bentazon, was observed on polymeric film of complex 20. The current response of the herbicide on this film was better than that observed on bare GCE. Electrocatalysis of the analytes, on the respective modified electrodes, occurred via closely related mechanisms.
- Full Text:
- Date Issued: 2011
- Authors: Akinbulu, Isaac Adebayo
- Date: 2011
- Subjects: Phthalocyanines Electrochemistry Electrocatalysis Pesticides
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4365 , http://hdl.handle.net/10962/d1005030
- Description: New cobalt (13, 16 19 and 22), manganese (14, 17, 20 and 23) and iron (15, 18, 21 and 24)phthalocyanine complexes were synthesized and characterized. The UV-Vis spectral properties of the complexes were typical of the nature of central metal and position of substituent on the Pc ligand. Their electrochemical behaviors were signatures of the central metals, with varying influences of the nature and position of substituents. Nanocomposite of complex 18 and single walled carbon nanotubes (SWCNTs) (SWCNT-18)was fabricated. Formation of this nano-composite was confirmed by infrared (IR)spectroscopy, X-ray diffraction (XRD) spectroscopy and transmission electron microscopy (TEM). Self-assembled monolayers (SAMs) of SWCNT-18, complexes 13-15, and 20 were electropolymerized on glassy carbon electrodes (GCE). Complex 14 was also electrodeposited on GCE. Surface properties of the SAMs were consistent with the molecular feature of the substituent and the nature of central metal in the adsorbed species, while those of the MnPc modified GCEs were dependent on point of substitution and number of substituent. The SAM-modified gold electrodes were used for the electrocatalytic oxidation of the carbamate insecticide, carbofuran. Amplification of the current signal of the insecticide, at more energetically feasible oxidation potentials, on the SAM-modified gold electrodes, relative to bare gold electrode,justified electrocatalysis. There was enhanced sensitivity (attributed to the presence of SWCNT) of the SWCNT-18-SAM-modified gold electrode towards carbofuran, relative to the signals observed on the other SAMs. Current response of the insecticide,bendiocarb, was also intensified, at more favorable oxidation potentials, on the MnPc (14 and 17) modified GCEs, relative to the response on bare GCE, substantiating electrocatalysis. Also, catalysis of the oxidation of the herbicide, bentazon, was observed on polymeric film of complex 20. The current response of the herbicide on this film was better than that observed on bare GCE. Electrocatalysis of the analytes, on the respective modified electrodes, occurred via closely related mechanisms.
- Full Text:
- Date Issued: 2011
Automating the conversion of natural language fiction to multi-modal 3D animated virtual environments
- Authors: Glass, Kevin Robert
- Date: 2009
- Subjects: Virtual computer systems , Virtual storage (Computer science) , Virtual reality , Computer animation , Fiction -- Computer programs , Narration (Rhetoric) -- Computer simulation , Animation (Cinematography) , Natural language processing (Computer Science)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4632 , http://hdl.handle.net/10962/d1006518
- Description: Popular fiction books describe rich visual environments that contain characters, objects, and behaviour. This research develops automated processes for converting text sourced from fiction books into animated virtual environments and multi-modal films. This involves the analysis of unrestricted natural language fiction to identify appropriate visual descriptions, and the interpretation of the identified descriptions for constructing animated 3D virtual environments. The goal of the text analysis stage is the creation of annotated fiction text, which identifies visual descriptions in a structured manner. A hierarchical rule-based learning system is created that induces patterns from example annotations provided by a human, and uses these for the creation of additional annotations. Patterns are expressed as tree structures that abstract the input text on different levels according to structural (token, sentence) and syntactic (parts-of-speech, syntactic function) categories. Patterns are generalized using pair-wise merging, where dissimilar sub-trees are replaced with wild-cards. The result is a small set of generalized patterns that are able to create correct annotations. A set of generalized patterns represents a model of an annotator's mental process regarding a particular annotation category. Annotated text is interpreted automatically for constructing detailed scene descriptions. This includes identifying which scenes to visualize, and identifying the contents and behaviour in each scene. Entity behaviour in a 3D virtual environment is formulated using time-based constraints that are automatically derived from annotations. Constraints are expressed as non-linear symbolic functions that restrict the trajectories of a pair of entities over a continuous interval of time. Solutions to these constraints specify precise behaviour. We create an innovative quantified constraint optimizer for locating sound solutions, which uses interval arithmetic for treating time and space as contiguous quantities. This optimization method uses a technique of constraint relaxation and tightening that allows solution approximations to be located where constraint systems are inconsistent (an ability not previously explored in interval-based quantified constraint solving). 3D virtual environments are populated by automatically selecting geometric models or procedural geometry-creation methods from a library. 3D models are animated according to trajectories derived from constraint solutions. The final animated film is sequenced using a range of modalities including animated 3D graphics, textual subtitles, audio narrations, and foleys. Hierarchical rule-based learning is evaluated over a range of annotation categories. Models are induced for different categories of annotation without modifying the core learning algorithms, and these models are shown to be applicable to different types of books. Models are induced automatically with accuracies ranging between 51.4% and 90.4%, depending on the category. We show that models are refined if further examples are provided, and this supports a boot-strapping process for training the learning mechanism. The task of interpreting annotated fiction text and populating 3D virtual environments is successfully automated using our described techniques. Detailed scene descriptions are created accurately, where between 83% and 96% of the automatically generated descriptions require no manual modification (depending on the type of description). The interval-based quantified constraint optimizer fully automates the behaviour specification process. Sample animated multi-modal 3D films are created using extracts from fiction books that are unrestricted in terms of complexity or subject matter (unlike existing text-to-graphics systems). These examples demonstrate that: behaviour is visualized that corresponds to the descriptions in the original text; appropriate geometry is selected (or created) for visualizing entities in each scene; sequences of scenes are created for a film-like presentation of the story; and that multiple modalities are combined to create a coherent multi-modal representation of the fiction text. This research demonstrates that visual descriptions in fiction text can be automatically identified, and that these descriptions can be converted into corresponding animated virtual environments. Unlike existing text-to-graphics systems, we describe techniques that function over unrestricted natural language text and perform the conversion process without the need for manually constructed repositories of world knowledge. This enables the rapid production of animated 3D virtual environments, allowing the human designer to focus on creative aspects.
- Full Text:
- Date Issued: 2009
- Authors: Glass, Kevin Robert
- Date: 2009
- Subjects: Virtual computer systems , Virtual storage (Computer science) , Virtual reality , Computer animation , Fiction -- Computer programs , Narration (Rhetoric) -- Computer simulation , Animation (Cinematography) , Natural language processing (Computer Science)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4632 , http://hdl.handle.net/10962/d1006518
- Description: Popular fiction books describe rich visual environments that contain characters, objects, and behaviour. This research develops automated processes for converting text sourced from fiction books into animated virtual environments and multi-modal films. This involves the analysis of unrestricted natural language fiction to identify appropriate visual descriptions, and the interpretation of the identified descriptions for constructing animated 3D virtual environments. The goal of the text analysis stage is the creation of annotated fiction text, which identifies visual descriptions in a structured manner. A hierarchical rule-based learning system is created that induces patterns from example annotations provided by a human, and uses these for the creation of additional annotations. Patterns are expressed as tree structures that abstract the input text on different levels according to structural (token, sentence) and syntactic (parts-of-speech, syntactic function) categories. Patterns are generalized using pair-wise merging, where dissimilar sub-trees are replaced with wild-cards. The result is a small set of generalized patterns that are able to create correct annotations. A set of generalized patterns represents a model of an annotator's mental process regarding a particular annotation category. Annotated text is interpreted automatically for constructing detailed scene descriptions. This includes identifying which scenes to visualize, and identifying the contents and behaviour in each scene. Entity behaviour in a 3D virtual environment is formulated using time-based constraints that are automatically derived from annotations. Constraints are expressed as non-linear symbolic functions that restrict the trajectories of a pair of entities over a continuous interval of time. Solutions to these constraints specify precise behaviour. We create an innovative quantified constraint optimizer for locating sound solutions, which uses interval arithmetic for treating time and space as contiguous quantities. This optimization method uses a technique of constraint relaxation and tightening that allows solution approximations to be located where constraint systems are inconsistent (an ability not previously explored in interval-based quantified constraint solving). 3D virtual environments are populated by automatically selecting geometric models or procedural geometry-creation methods from a library. 3D models are animated according to trajectories derived from constraint solutions. The final animated film is sequenced using a range of modalities including animated 3D graphics, textual subtitles, audio narrations, and foleys. Hierarchical rule-based learning is evaluated over a range of annotation categories. Models are induced for different categories of annotation without modifying the core learning algorithms, and these models are shown to be applicable to different types of books. Models are induced automatically with accuracies ranging between 51.4% and 90.4%, depending on the category. We show that models are refined if further examples are provided, and this supports a boot-strapping process for training the learning mechanism. The task of interpreting annotated fiction text and populating 3D virtual environments is successfully automated using our described techniques. Detailed scene descriptions are created accurately, where between 83% and 96% of the automatically generated descriptions require no manual modification (depending on the type of description). The interval-based quantified constraint optimizer fully automates the behaviour specification process. Sample animated multi-modal 3D films are created using extracts from fiction books that are unrestricted in terms of complexity or subject matter (unlike existing text-to-graphics systems). These examples demonstrate that: behaviour is visualized that corresponds to the descriptions in the original text; appropriate geometry is selected (or created) for visualizing entities in each scene; sequences of scenes are created for a film-like presentation of the story; and that multiple modalities are combined to create a coherent multi-modal representation of the fiction text. This research demonstrates that visual descriptions in fiction text can be automatically identified, and that these descriptions can be converted into corresponding animated virtual environments. Unlike existing text-to-graphics systems, we describe techniques that function over unrestricted natural language text and perform the conversion process without the need for manually constructed repositories of world knowledge. This enables the rapid production of animated 3D virtual environments, allowing the human designer to focus on creative aspects.
- Full Text:
- Date Issued: 2009
Radio Frequency Identification (RFID) adoption in the South African retail sector: an investigation of perceptions held by members of the retail sector regarding the adoption constraints
- Authors: Liu, Haidi
- Date: 2008
- Subjects: Radio frequency identification systems , Retail trade -- South Africa , Business logistics -- Management -- South Africa , Retail trade -- Employees -- South Africa , Retail trade -- Technological innovations , Radio waves , Consumer profiling
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:1144 , http://hdl.handle.net/10962/d1002774 , Radio frequency identification systems , Retail trade -- South Africa , Business logistics -- Management -- South Africa , Retail trade -- Employees -- South Africa , Retail trade -- Technological innovations , Radio waves , Consumer profiling
- Description: Radio Frequency Identification (RFID) technology is a ethod of identifying unique items using radio waves that communicate between RFID tags and readers without line-of-sight readability. RFID technology provides great potential in many industries and a wide spectrum of possible uses. Areas of application include person identification, logistics, pharmaceutical, access control, security guard monitoring and asset management. One of the areas where RFID is being used and where it promises excellent results is the retail industry. While RFID systems have the potential to revolutionise the way products and goods are tracked and traced in the retail supply chain, barriers to its widespread adoption exist: for example; technical constraints, return on investment constraints, a lack of awareness and education and as well as privacy and security issues. The research aims to identify the barriers to the adoption of RFID and to investigate the perceptions of RFID held by members of the retail sector in South Africa (SA). Current research and available literature are used to identify RFID adoption barriers and a conceptual framework on this subject is proposed, which is then verified by SA retailers’ perceptions, established by means of a survey. Initial barriers to widespread adoption include a shortage in skills, a lack of standards, high costs associated with RFID devices, the difficulty of integrating with current legacy systems, and a lack of familiarity with the system. Finally, an enhanced framework is proposed, describing RFID adoption barriers within the South African retail sector. In summary, the framework is an outline of the barriers impacting RFID adoption in the SA retail sector that need to be considered and addressed. The framework identifies six categories of RFID adoption barriers, with each category containing two or more barriers relating to that particular category. These categories are Technological, Cost and return on investment, Privacy and security, Implementation, Organisational factors and People.
- Full Text:
- Date Issued: 2008
- Authors: Liu, Haidi
- Date: 2008
- Subjects: Radio frequency identification systems , Retail trade -- South Africa , Business logistics -- Management -- South Africa , Retail trade -- Employees -- South Africa , Retail trade -- Technological innovations , Radio waves , Consumer profiling
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:1144 , http://hdl.handle.net/10962/d1002774 , Radio frequency identification systems , Retail trade -- South Africa , Business logistics -- Management -- South Africa , Retail trade -- Employees -- South Africa , Retail trade -- Technological innovations , Radio waves , Consumer profiling
- Description: Radio Frequency Identification (RFID) technology is a ethod of identifying unique items using radio waves that communicate between RFID tags and readers without line-of-sight readability. RFID technology provides great potential in many industries and a wide spectrum of possible uses. Areas of application include person identification, logistics, pharmaceutical, access control, security guard monitoring and asset management. One of the areas where RFID is being used and where it promises excellent results is the retail industry. While RFID systems have the potential to revolutionise the way products and goods are tracked and traced in the retail supply chain, barriers to its widespread adoption exist: for example; technical constraints, return on investment constraints, a lack of awareness and education and as well as privacy and security issues. The research aims to identify the barriers to the adoption of RFID and to investigate the perceptions of RFID held by members of the retail sector in South Africa (SA). Current research and available literature are used to identify RFID adoption barriers and a conceptual framework on this subject is proposed, which is then verified by SA retailers’ perceptions, established by means of a survey. Initial barriers to widespread adoption include a shortage in skills, a lack of standards, high costs associated with RFID devices, the difficulty of integrating with current legacy systems, and a lack of familiarity with the system. Finally, an enhanced framework is proposed, describing RFID adoption barriers within the South African retail sector. In summary, the framework is an outline of the barriers impacting RFID adoption in the SA retail sector that need to be considered and addressed. The framework identifies six categories of RFID adoption barriers, with each category containing two or more barriers relating to that particular category. These categories are Technological, Cost and return on investment, Privacy and security, Implementation, Organisational factors and People.
- Full Text:
- Date Issued: 2008
Metal complexes of black wattle tannins and related model polyphenols
- Authors: Slabbert, Neville Patrick
- Date: 1973
- Subjects: Metal complexes Tannins
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4432 , http://hdl.handle.net/10962/d1007407
- Description: Apart from their general usage as tanning agents for hides and skins, the natural tannins have been used since earliest times for various other purposes. The blue-black iron tannate complex was used by ancient Egyptians as a hairdye and for many conturies this complex was the main source of writing inks. Wattle tannin is known to form complexes with many metal ions. The chief use of tannin complexes has been in gravimetric analyses, since aqueous solutions of tannins readily precipitate metal ions under certain experimentel conditions. At the present time the nature of the precipitated complexes has not been investigated however, because in the gravimetric method the complexes are ignited and the metal determined as its oxide; hence no knowledge of the complexes themselves was required.
- Full Text:
- Date Issued: 1973
- Authors: Slabbert, Neville Patrick
- Date: 1973
- Subjects: Metal complexes Tannins
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4432 , http://hdl.handle.net/10962/d1007407
- Description: Apart from their general usage as tanning agents for hides and skins, the natural tannins have been used since earliest times for various other purposes. The blue-black iron tannate complex was used by ancient Egyptians as a hairdye and for many conturies this complex was the main source of writing inks. Wattle tannin is known to form complexes with many metal ions. The chief use of tannin complexes has been in gravimetric analyses, since aqueous solutions of tannins readily precipitate metal ions under certain experimentel conditions. At the present time the nature of the precipitated complexes has not been investigated however, because in the gravimetric method the complexes are ignited and the metal determined as its oxide; hence no knowledge of the complexes themselves was required.
- Full Text:
- Date Issued: 1973
Ionospheric studies of the solar eclipse 25 December, 1954
- Authors: McElhinny, M W
- Date: 1959
- Subjects: Ionosphere -- Research , Solar eclipses
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5531 , http://hdl.handle.net/10962/d1012869
- Description: Since the Kennelly- Heaviside hypothesis in 1902 of the existence of a partially conducting layer in the upper atmosphere was proved to be true by the experiments of APPLETON and BARNETT (1925) and BREIT and TUVE (1926), this region has become known as the ionosphere. The ionosphere was soon discovered to consist of, not one but several layers (Fig. 1) (i) A layer at a height of just over 100 km. called the E layer. (ii) A layer at a height of approximately 300km. called the F₂ layer. (iii) A layer at a height of approximately 200 km. called the F₁ layer; this layer differs from the other two in that it is only present during the day time in Summer. (iv) Occasional intense reflections from a height of about 100 km. are found - these cannot be attributed to the normal E layer and have received the name "Sporadic E". The presence of two E layers (E₁ and E₂) has been suggested by HALLIDAY (1936) and BEST and RATCLIFFE (l978) but until recently most workers still seem to attribute these reflections to Sporadic E. Recent measurement by rockets of the electron density at E layer heights still do not confirm whether such bifurcation exists in the E region. The diurnal and seasonal variations of the first three layers indicate that the sun is the chief agent in their production. It is generally agreed that these layers consist of ionised molecules or atoms and free electrons produced by radiation from the sun. The origin of Sporadic E ionisation is still obscure, but it is thought that these sudden increases in ionisation which occur in E layer heights are due to passing meteors. Recently it has also been suggested by SEDDON, PICKAR and JACKSON (1954) from rocket measurements that Sporadic E might be due to a steep electron density gradient above the B layer.
- Full Text:
- Date Issued: 1959
- Authors: McElhinny, M W
- Date: 1959
- Subjects: Ionosphere -- Research , Solar eclipses
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5531 , http://hdl.handle.net/10962/d1012869
- Description: Since the Kennelly- Heaviside hypothesis in 1902 of the existence of a partially conducting layer in the upper atmosphere was proved to be true by the experiments of APPLETON and BARNETT (1925) and BREIT and TUVE (1926), this region has become known as the ionosphere. The ionosphere was soon discovered to consist of, not one but several layers (Fig. 1) (i) A layer at a height of just over 100 km. called the E layer. (ii) A layer at a height of approximately 300km. called the F₂ layer. (iii) A layer at a height of approximately 200 km. called the F₁ layer; this layer differs from the other two in that it is only present during the day time in Summer. (iv) Occasional intense reflections from a height of about 100 km. are found - these cannot be attributed to the normal E layer and have received the name "Sporadic E". The presence of two E layers (E₁ and E₂) has been suggested by HALLIDAY (1936) and BEST and RATCLIFFE (l978) but until recently most workers still seem to attribute these reflections to Sporadic E. Recent measurement by rockets of the electron density at E layer heights still do not confirm whether such bifurcation exists in the E region. The diurnal and seasonal variations of the first three layers indicate that the sun is the chief agent in their production. It is generally agreed that these layers consist of ionised molecules or atoms and free electrons produced by radiation from the sun. The origin of Sporadic E ionisation is still obscure, but it is thought that these sudden increases in ionisation which occur in E layer heights are due to passing meteors. Recently it has also been suggested by SEDDON, PICKAR and JACKSON (1954) from rocket measurements that Sporadic E might be due to a steep electron density gradient above the B layer.
- Full Text:
- Date Issued: 1959
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