The relationship between the alcohol use patterns and cognitive and symptomatic functioning of Rhodes University students
- Authors: Mayson, Tamara Ann
- Date: 2016
- Subjects: Drinking of alcholic beverages -- South Africa , Rhodes University -- Students -- Alcohol use , Alcohol -- Physiological effect
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3270 , http://hdl.handle.net/10962/d1020327
- Description: Introduction: Studies reveal differential cognitive effects of alcohol use, with moderate to heavy alcohol having some beneficial effects in older adults, whereas in young adulthood, heavier alcohol use produces deficits. The aim of the research was to investigate the relationship between patterns of alcohol use and the cognitive and symptomatic functioning of university students over one year, and to discern which demographic, clinical and alcohol factors might moderate cognitive outcomes. Method: The sample included undergraduate Psychology students from a South African University, aged 18 to 23 years (n = 86). The sample was divided into two alcohol use groups based on four categories from the Alcohol Use Disorders Identification Test (AUDIT) (Babor et al., 2001), including a lighter drinking group (Safe/Hazardous, n = 74) and a heavier drinking group (Harmful/Dependent, n = 12). The two drinking groups were statistically equivalent for distribution of age, gender, English first language, race groups, history of neurological or psychiatric vulnerability, a measure of initial intelligence/cognitive reserve (Peabody Picture Vocabulary Test: PPVT-4) (Dunn & Dunn, 2007) and for a measure of test-taking validity (Immediate Postconcussion Assessment and Cognitive Test: ImPACT Impulse Control) (p = < 0.05 in all instances). Participants were tested on the computerized ImPACT battery (ImPACT, 2007) at three intervals over an academic year (May, August, October 2012). Repeated measures ANOVAs were used to investigate cognitive and symptomatic differences between the two alcohol use groups, in association with moderating factors. Results: The heavier drinking group revealed: (i) poorer performance on ImPACT Visual Motor Speed, Reaction Time and Cognitive Efficiency Index scores, including less ability to benefit from practice over time; (ii) symptom reports of severe Numbness/Tingling, Balance problems and Dizziness. Deleterious cognitive outcome was exacerbated by longer lifetime duration of alcohol use, passing out monthly, beer or wine drinking, smoking or substance use. Conclusion: Deleterious cognitive and symptomatic effects of heavy alcohol use are in evidence for undergraduate university students implicating current and/or cumulative alcohol induced brain impairment. The results of the study are of concern for optimal academic performance of students at an early stage of university level study, who engage in heavier (Harmful/Dependent) drinking patterns, with negative implications for future career attainment.
- Full Text:
- Date Issued: 2016
- Authors: Mayson, Tamara Ann
- Date: 2016
- Subjects: Drinking of alcholic beverages -- South Africa , Rhodes University -- Students -- Alcohol use , Alcohol -- Physiological effect
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3270 , http://hdl.handle.net/10962/d1020327
- Description: Introduction: Studies reveal differential cognitive effects of alcohol use, with moderate to heavy alcohol having some beneficial effects in older adults, whereas in young adulthood, heavier alcohol use produces deficits. The aim of the research was to investigate the relationship between patterns of alcohol use and the cognitive and symptomatic functioning of university students over one year, and to discern which demographic, clinical and alcohol factors might moderate cognitive outcomes. Method: The sample included undergraduate Psychology students from a South African University, aged 18 to 23 years (n = 86). The sample was divided into two alcohol use groups based on four categories from the Alcohol Use Disorders Identification Test (AUDIT) (Babor et al., 2001), including a lighter drinking group (Safe/Hazardous, n = 74) and a heavier drinking group (Harmful/Dependent, n = 12). The two drinking groups were statistically equivalent for distribution of age, gender, English first language, race groups, history of neurological or psychiatric vulnerability, a measure of initial intelligence/cognitive reserve (Peabody Picture Vocabulary Test: PPVT-4) (Dunn & Dunn, 2007) and for a measure of test-taking validity (Immediate Postconcussion Assessment and Cognitive Test: ImPACT Impulse Control) (p = < 0.05 in all instances). Participants were tested on the computerized ImPACT battery (ImPACT, 2007) at three intervals over an academic year (May, August, October 2012). Repeated measures ANOVAs were used to investigate cognitive and symptomatic differences between the two alcohol use groups, in association with moderating factors. Results: The heavier drinking group revealed: (i) poorer performance on ImPACT Visual Motor Speed, Reaction Time and Cognitive Efficiency Index scores, including less ability to benefit from practice over time; (ii) symptom reports of severe Numbness/Tingling, Balance problems and Dizziness. Deleterious cognitive outcome was exacerbated by longer lifetime duration of alcohol use, passing out monthly, beer or wine drinking, smoking or substance use. Conclusion: Deleterious cognitive and symptomatic effects of heavy alcohol use are in evidence for undergraduate university students implicating current and/or cumulative alcohol induced brain impairment. The results of the study are of concern for optimal academic performance of students at an early stage of university level study, who engage in heavier (Harmful/Dependent) drinking patterns, with negative implications for future career attainment.
- Full Text:
- Date Issued: 2016
A narrative exploration of the experiences of children from child-headed households into early adulthood : a case study of Nkonkobe District, Eastern Cape
- Authors: Sumbulu, Manowa Abie
- Date: 2015
- Subjects: Children's rights--South Africa--Eastern Cape Child caregivers--South Africa--Eastern Cape Children--Legal status, laws, etc.--South Africa--Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Social Work
- Identifier: http://hdl.handle.net/10353/11850 , vital:39112
- Description: The past three decades have seen dramatic changes within the childcare system. There has been a bourgeoning death rate of child-bearing parents resulting in an unprecedentedly high number of parentless children (orphans) leading to the formation of child-headed households (CHHs). This formation came about as a result of the paucity of informal care for such children as well as the incapacity of the formal child care system. Most of these children are disadvantages with the prospect of facing a bleak future. However, some of them survive and presumably make it in life despite the odds. It is resilience and strengths they have in coping with their life’s’ situations that the research addresses. An exploratory-descriptive and qualitative design was applied in this research as well as Guba's (1981) approach to ensuring trustworthiness in qualitative research. A systematic probability sampling procedure was applied in selecting participants. A semi-structured interview schedule with open-ended questions was applied to both the pilot study and to the study proper. The latter was conducted in the form of fourteen in-depth interviews and a focus group of eight discussants. The protocols were explicated in terms of a full delineation of the themes while the data were analysed by utilizing the thematic approach based on the grounded theory. Three developmental stages were identified: their base before becoming a child-headed household; the transition stage when they were in the child-headed household and the central narrative of how they progressed and coped since leaving the CHH. The third stage was the time for reflecting on what they had gone through and offered advice on coping capacity to children who might find themselves in child-headed households. Each of these stages has been marked by its highs and lows as they navigate through life and developing coping strategies. Some of these coping mechanisms were stage-specific while others persisted through all the stages.
- Full Text:
- Date Issued: 2015
- Authors: Sumbulu, Manowa Abie
- Date: 2015
- Subjects: Children's rights--South Africa--Eastern Cape Child caregivers--South Africa--Eastern Cape Children--Legal status, laws, etc.--South Africa--Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Social Work
- Identifier: http://hdl.handle.net/10353/11850 , vital:39112
- Description: The past three decades have seen dramatic changes within the childcare system. There has been a bourgeoning death rate of child-bearing parents resulting in an unprecedentedly high number of parentless children (orphans) leading to the formation of child-headed households (CHHs). This formation came about as a result of the paucity of informal care for such children as well as the incapacity of the formal child care system. Most of these children are disadvantages with the prospect of facing a bleak future. However, some of them survive and presumably make it in life despite the odds. It is resilience and strengths they have in coping with their life’s’ situations that the research addresses. An exploratory-descriptive and qualitative design was applied in this research as well as Guba's (1981) approach to ensuring trustworthiness in qualitative research. A systematic probability sampling procedure was applied in selecting participants. A semi-structured interview schedule with open-ended questions was applied to both the pilot study and to the study proper. The latter was conducted in the form of fourteen in-depth interviews and a focus group of eight discussants. The protocols were explicated in terms of a full delineation of the themes while the data were analysed by utilizing the thematic approach based on the grounded theory. Three developmental stages were identified: their base before becoming a child-headed household; the transition stage when they were in the child-headed household and the central narrative of how they progressed and coped since leaving the CHH. The third stage was the time for reflecting on what they had gone through and offered advice on coping capacity to children who might find themselves in child-headed households. Each of these stages has been marked by its highs and lows as they navigate through life and developing coping strategies. Some of these coping mechanisms were stage-specific while others persisted through all the stages.
- Full Text:
- Date Issued: 2015
A framework for the development and measurement of agile enterprise architecture
- Authors: Mthupha, Bokang
- Date: 2012
- Subjects: Management information systems -- Research Industrial management -- Technological innovations -- Research Industrial organization -- Technological innovations -- Research System design
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1147 , http://hdl.handle.net/10962/d1002777
- Description: Enterprise architecture is the high-level design of the entire business, facilitated by enterprise architects. "Agile enterprise architecture" is the term used in enterprise architecture to describe an architecture that caters for future unknowns, enabling change to occur rapidly without undue resource utilization, yet in a controlled manner and with minimal adverse impact. Some enterprise architects still use outdated, rigid approaches to enterprise architecture which are incompatible with today‟s business environment. In addition, there is limited research into methods that can be applied to measure the agility of enterprise architecture. The current environment is such that there is a need for a more agile approach to developing and measuring enterprise architecture. This work will lead to the creation of a Framework for The Development and Measurement of Agile Enterprise Architecture. In support of the main goal of the development of the framework, a literature review will be conducted focusing on the necessary sub-goals of the research. The first sub-goal of the literature review is to develop a comprehensive definition for enterprise architecture (referred to as EA), as well as discover how it is currently practiced. Thereafter, the literature review will investigate a comprehensive definition for agility and research why it is emerging as a critical topic. The next chapter of the literature review will research how agility fits within the context of EA, uncovering a comprehensive definition for agile EA and the best practices in agile EA development. The final chapter of the literature review will investigate suitable measurement techniques that can be used to assess the level of agility of EA. On completion of the literature review, a preliminary framework will be created using the most important contributions from the literature. An empirical study will be conducted to explore the definitions for EA, agility, agile EA, the methods to measure the agility of EA and the concepts for the development of agile EA summarised in the preliminary framework. Data analysis follows an interpretive and qualitative approach based on four case studies through interviews with systems experts in four South African organizations in one province. Each interviewee was interviewed once. The initial interview with a Principal Consultant on Enterprise Strategy Consulting at organisation # 1 formed the basis of an exploratory study; the results of which were used to refine the research instrument and preliminary framework. Thereafter, a more rigorous empirical study focused on interviews with the Chief Architect, Senior Manager in Advisory Services and an Enterprise Architect at organizations 2, 3 and 4 respectively was conducted. The research follows an inductive approach to capture the interpretive experiences of participants and develop theoretical propositions from them. Following the exploratory pilot study it became necessary to make changes to the preliminary framework and initial survey instrument created. Thereafter, the empirical study consisting of the remaining three cases was conducted to test the important aspects of the framework and literature definitions. The analysis of the results of the empirical study prompted further changes to the theoretical framework and definitions created. The interviews conducted with each of the organizations confirmed the factors for agile EA development as well as the effectiveness of the definitions created in the literature review. The research uncovered that the need for a more agile approach to developing EA and a way to measure the level of agility of EA has become more and more significant in organizations. This begins with a better understanding of EA, agility, how agility fits within the context of EA, as well as appropriate methods to measure agility.
- Full Text:
- Date Issued: 2012
- Authors: Mthupha, Bokang
- Date: 2012
- Subjects: Management information systems -- Research Industrial management -- Technological innovations -- Research Industrial organization -- Technological innovations -- Research System design
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1147 , http://hdl.handle.net/10962/d1002777
- Description: Enterprise architecture is the high-level design of the entire business, facilitated by enterprise architects. "Agile enterprise architecture" is the term used in enterprise architecture to describe an architecture that caters for future unknowns, enabling change to occur rapidly without undue resource utilization, yet in a controlled manner and with minimal adverse impact. Some enterprise architects still use outdated, rigid approaches to enterprise architecture which are incompatible with today‟s business environment. In addition, there is limited research into methods that can be applied to measure the agility of enterprise architecture. The current environment is such that there is a need for a more agile approach to developing and measuring enterprise architecture. This work will lead to the creation of a Framework for The Development and Measurement of Agile Enterprise Architecture. In support of the main goal of the development of the framework, a literature review will be conducted focusing on the necessary sub-goals of the research. The first sub-goal of the literature review is to develop a comprehensive definition for enterprise architecture (referred to as EA), as well as discover how it is currently practiced. Thereafter, the literature review will investigate a comprehensive definition for agility and research why it is emerging as a critical topic. The next chapter of the literature review will research how agility fits within the context of EA, uncovering a comprehensive definition for agile EA and the best practices in agile EA development. The final chapter of the literature review will investigate suitable measurement techniques that can be used to assess the level of agility of EA. On completion of the literature review, a preliminary framework will be created using the most important contributions from the literature. An empirical study will be conducted to explore the definitions for EA, agility, agile EA, the methods to measure the agility of EA and the concepts for the development of agile EA summarised in the preliminary framework. Data analysis follows an interpretive and qualitative approach based on four case studies through interviews with systems experts in four South African organizations in one province. Each interviewee was interviewed once. The initial interview with a Principal Consultant on Enterprise Strategy Consulting at organisation # 1 formed the basis of an exploratory study; the results of which were used to refine the research instrument and preliminary framework. Thereafter, a more rigorous empirical study focused on interviews with the Chief Architect, Senior Manager in Advisory Services and an Enterprise Architect at organizations 2, 3 and 4 respectively was conducted. The research follows an inductive approach to capture the interpretive experiences of participants and develop theoretical propositions from them. Following the exploratory pilot study it became necessary to make changes to the preliminary framework and initial survey instrument created. Thereafter, the empirical study consisting of the remaining three cases was conducted to test the important aspects of the framework and literature definitions. The analysis of the results of the empirical study prompted further changes to the theoretical framework and definitions created. The interviews conducted with each of the organizations confirmed the factors for agile EA development as well as the effectiveness of the definitions created in the literature review. The research uncovered that the need for a more agile approach to developing EA and a way to measure the level of agility of EA has become more and more significant in organizations. This begins with a better understanding of EA, agility, how agility fits within the context of EA, as well as appropriate methods to measure agility.
- Full Text:
- Date Issued: 2012
The existence of the value premium on the Johannesburg Stock Exchange from 1972 to 2001 and extrapolation as explanation
- Authors: Beukes, Anna
- Date: 2011
- Subjects: Johannesburg Stock Exchange Stocks -- Prices -- South Africa Rational expectations (Economic theory) Investments -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:977 , http://hdl.handle.net/10962/d1002711
- Description: This study investigates the existence of the value premium in South Africa’s equity market, and tests extrapolation as a possible explanation for it. The value premium refers to the widely reported superior performance of share price returns of value companies compared to growth companies. The value premium represents an anomaly in mainstream rational finance theory, because it should not persist, unless it could be explained as the result of some composite form of risk. What is highly vexing is the fact that the value premium not only persists in most financial markets over a long period, but that the risk explanation cannot be upheld convincingly. This contributed to the rise of behavioral finance, an approach which introduces psychological factors to provide new explanations for financial phenomena. The behavioral finance explanation for the value premium observation is extrapolation (the tendency to project recent experience too far into the future). This study applies propositions and methods from behavioral finance to investigate the South African equity market. The existence of a value premium in South Africa was investigated by using twenty-nine years’ worth of accounting and share price data. The study employed one- and two-dimensional tests for portfolio formation, and tracked share price returns for up to five years after portfolio formation. The results indicated that a statistically and economically significant value premium existed in South Africa for the period between 1972 and 2001. Extrapolation as a potential explanation for the value premium observation was investigated by applying internationally used methods. Extrapolation was found to provide a robust explanation for the South African value premium.
- Full Text:
- Date Issued: 2011
- Authors: Beukes, Anna
- Date: 2011
- Subjects: Johannesburg Stock Exchange Stocks -- Prices -- South Africa Rational expectations (Economic theory) Investments -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:977 , http://hdl.handle.net/10962/d1002711
- Description: This study investigates the existence of the value premium in South Africa’s equity market, and tests extrapolation as a possible explanation for it. The value premium refers to the widely reported superior performance of share price returns of value companies compared to growth companies. The value premium represents an anomaly in mainstream rational finance theory, because it should not persist, unless it could be explained as the result of some composite form of risk. What is highly vexing is the fact that the value premium not only persists in most financial markets over a long period, but that the risk explanation cannot be upheld convincingly. This contributed to the rise of behavioral finance, an approach which introduces psychological factors to provide new explanations for financial phenomena. The behavioral finance explanation for the value premium observation is extrapolation (the tendency to project recent experience too far into the future). This study applies propositions and methods from behavioral finance to investigate the South African equity market. The existence of a value premium in South Africa was investigated by using twenty-nine years’ worth of accounting and share price data. The study employed one- and two-dimensional tests for portfolio formation, and tracked share price returns for up to five years after portfolio formation. The results indicated that a statistically and economically significant value premium existed in South Africa for the period between 1972 and 2001. Extrapolation as a potential explanation for the value premium observation was investigated by applying internationally used methods. Extrapolation was found to provide a robust explanation for the South African value premium.
- Full Text:
- Date Issued: 2011
Habitat segregation in competing species of intertidal mussels in South Africa
- Authors: Bownes, Sarah
- Date: 2006
- Subjects: Mussels -- South Africa Mussels -- Growth Mussels -- Habitat -- South Africa Mussels -- Larvae Perna -- South Africa Mytilus galloprovincialis -- South Africa Choromytilus meridionalis -- South Africa Mytilidae -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5706 , http://hdl.handle.net/10962/d1005392
- Description: Mytilus galloprovincialis is invasive on rocky shores on the west coast of South Africa where it has become the dominant intertidal mussel. The success of this species on the west coast and its superior competitive abilities, have led to concern that it may become invasive on the south coast at the expense of the indigenous mussel Perna perna. On shores where these species co-occur, there appears to be habitat segregation among zones occupied by mussels. M.galloprovincialis dominates the high-shore and P.perna the low-shore, with a mixed zone at mid-shore level. This study examined the factors responsible for these differences in distribution and abundance. The study was conducted in Plettenberg Bay and Tsitsikamma (70km apart) on the south coast of South Africa. Each site included two randomly selected locations (300-400m apart). A third mussel species, Choromytilus meridionalis, is found in large numbers at the sand/rock interface at one location in Plettenberg Bay. Aspects of settlement, recruitment, growth and mortality of juvenile and adult mussels were examined at different tidal heights at each site. Quantitative analysis of mussel population structure at these sites supported the initial observation of vertical habitat segregation. Post-larvae were identified to species and this was confirmed using hinge morphology and mitochondrial DNA analysis. Size at settlement was determined for each species to differentiate between primary and secondary settlement. Adult distribution of C.meridionalis was primarily determined by settlement, which was highly selective in this species. Settlement, recruitment and growth of P.perna decreased with increasing tidal height, while post-settlement mortality and adult mortality increased higher upshore. Thus all aspects of P.perna’s life history contribute to the adult distribution of this species. Presumably, the abundance of P.perna on the high-shore is initially limited by recruitment while those that survive remain prone to elimination throughout adulthood. M.galloprovincialis displayed the same patterns of settlement and recruitment as P.perna. However, post-settlement mortality in this species was consistently low in the low and high zones. Juvenile growth also decreased upshore, suggesting that M.galloprovincialis may be able to maintain high densities on the high-shore through the persistence of successive settlements of slow-growing individuals. The low cover of M.galloprovincialis on the lowshore appeared to be determined by adult interactions. M.galloprovincialis experienced significantly higher adult mortality rates than P.perna in this zone. There were seasonal variations in the competitive advantages enjoyed by each species through growth, recruitment or mortality on the low-shore. In summer, P.perna had higher recruitment rates, faster growth and lower mortality rates, while M.galloprovincialis had slightly higher recruitment rates and faster growth rates in winter. P.perna is a warm water species while M.galloprovincialis thrives on the cold-temperate west coast of South Africa. Therefore both species appear to be at the edge of their optimal temperature regimes on the south coast, which may explain the seasonal advantages of each. Nevertheless, P.perna has maintained spatial dominance on the low-shore suggesting that it may ultimately be the winner in competition between these species. M.galloprovincialis appears to have a refuge from competition with P.perna on the high-shore due to its greater tolerance of desiccation stress, while being competitively excluded from the low-shore. Warm water temperatures coupled with poor recruitment rates at most sites may limit the success of M.galloprovincialis on this coast.
- Full Text:
- Date Issued: 2006
- Authors: Bownes, Sarah
- Date: 2006
- Subjects: Mussels -- South Africa Mussels -- Growth Mussels -- Habitat -- South Africa Mussels -- Larvae Perna -- South Africa Mytilus galloprovincialis -- South Africa Choromytilus meridionalis -- South Africa Mytilidae -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5706 , http://hdl.handle.net/10962/d1005392
- Description: Mytilus galloprovincialis is invasive on rocky shores on the west coast of South Africa where it has become the dominant intertidal mussel. The success of this species on the west coast and its superior competitive abilities, have led to concern that it may become invasive on the south coast at the expense of the indigenous mussel Perna perna. On shores where these species co-occur, there appears to be habitat segregation among zones occupied by mussels. M.galloprovincialis dominates the high-shore and P.perna the low-shore, with a mixed zone at mid-shore level. This study examined the factors responsible for these differences in distribution and abundance. The study was conducted in Plettenberg Bay and Tsitsikamma (70km apart) on the south coast of South Africa. Each site included two randomly selected locations (300-400m apart). A third mussel species, Choromytilus meridionalis, is found in large numbers at the sand/rock interface at one location in Plettenberg Bay. Aspects of settlement, recruitment, growth and mortality of juvenile and adult mussels were examined at different tidal heights at each site. Quantitative analysis of mussel population structure at these sites supported the initial observation of vertical habitat segregation. Post-larvae were identified to species and this was confirmed using hinge morphology and mitochondrial DNA analysis. Size at settlement was determined for each species to differentiate between primary and secondary settlement. Adult distribution of C.meridionalis was primarily determined by settlement, which was highly selective in this species. Settlement, recruitment and growth of P.perna decreased with increasing tidal height, while post-settlement mortality and adult mortality increased higher upshore. Thus all aspects of P.perna’s life history contribute to the adult distribution of this species. Presumably, the abundance of P.perna on the high-shore is initially limited by recruitment while those that survive remain prone to elimination throughout adulthood. M.galloprovincialis displayed the same patterns of settlement and recruitment as P.perna. However, post-settlement mortality in this species was consistently low in the low and high zones. Juvenile growth also decreased upshore, suggesting that M.galloprovincialis may be able to maintain high densities on the high-shore through the persistence of successive settlements of slow-growing individuals. The low cover of M.galloprovincialis on the lowshore appeared to be determined by adult interactions. M.galloprovincialis experienced significantly higher adult mortality rates than P.perna in this zone. There were seasonal variations in the competitive advantages enjoyed by each species through growth, recruitment or mortality on the low-shore. In summer, P.perna had higher recruitment rates, faster growth and lower mortality rates, while M.galloprovincialis had slightly higher recruitment rates and faster growth rates in winter. P.perna is a warm water species while M.galloprovincialis thrives on the cold-temperate west coast of South Africa. Therefore both species appear to be at the edge of their optimal temperature regimes on the south coast, which may explain the seasonal advantages of each. Nevertheless, P.perna has maintained spatial dominance on the low-shore suggesting that it may ultimately be the winner in competition between these species. M.galloprovincialis appears to have a refuge from competition with P.perna on the high-shore due to its greater tolerance of desiccation stress, while being competitively excluded from the low-shore. Warm water temperatures coupled with poor recruitment rates at most sites may limit the success of M.galloprovincialis on this coast.
- Full Text:
- Date Issued: 2006
Operationally defining sexual orientation : towards the development of a fundamental measure of adolescent sexual responsiveness variations
- Authors: Heath, Lance Julian
- Date: 2005
- Subjects: Sexual orientation Homosexuality Psychometrics Teenagers--Sexual behavior
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1681 , http://hdl.handle.net/10962/d1003564
- Description: Much published work has pointed to the need for the development of a sound operational definition of sexual orientation in order to enable the research in this area to progress. To contribute to this process the current research set out to develop two measures of sexual orientation and examine their psychometric properties. In order to develop relevant tools historical, conceptual and operational definitions of sexual orientation were critically examined and standard questionnaire development techniques applied. The first scale consisted of 32 items and was administered to a total of 835 adolescents, comprising three sub-groups (189 Grade 11 Scholars, 547 First Year and 99 Third Year Psychology Students). A Cronbach alpha coefficient of 0.85 was calculated indicating that this instrument had very good internal consistency reliability. Similar factors emerged in each of the sample sub-groups when factor analyses were performed suggesting that this instrument has good external and construct validities. These factors each had respectable Cronbach alpha coefficients indicating their own internal consistency. The four factors which consistently emerged were Same Sex Responsiveness, Opposite Sex Responsiveness, Previous Month’s Same Sex Responsiveness and Previous Month’s Opposite Sex Responsiveness. The second scale consisted of 16 items and was administered to 646 adolescents, comprising the latter two sub-groups referred to above. A Cronbach alpha coefficient of 0.82 was calculated indicating that this instrument also had very good internal consistency reliability. Once again similar factors with generally good internal consistency emerged in factor analysis suggesting that this too was a valid instrument. The factors that emerged from the second scale were Same Sex Responsiveness, Unattractive Opposite Sex Responsiveness, Attractive Opposite Sex Responsiveness and Attraction. Future developments, adjustments and applications of the instruments as well as implications for the arena of sexual orientation research are discussed. In the light of the dearth of information with regard to the sexual orientations of South African adolescents the current study also briefly explored and presented the sample’s responses in terms of the dimensions of each questionnaire as well as how each emerging factor related to the demographics (education level, gender, sexual orientation self-label and age) of the sample.
- Full Text:
- Date Issued: 2005
- Authors: Heath, Lance Julian
- Date: 2005
- Subjects: Sexual orientation Homosexuality Psychometrics Teenagers--Sexual behavior
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1681 , http://hdl.handle.net/10962/d1003564
- Description: Much published work has pointed to the need for the development of a sound operational definition of sexual orientation in order to enable the research in this area to progress. To contribute to this process the current research set out to develop two measures of sexual orientation and examine their psychometric properties. In order to develop relevant tools historical, conceptual and operational definitions of sexual orientation were critically examined and standard questionnaire development techniques applied. The first scale consisted of 32 items and was administered to a total of 835 adolescents, comprising three sub-groups (189 Grade 11 Scholars, 547 First Year and 99 Third Year Psychology Students). A Cronbach alpha coefficient of 0.85 was calculated indicating that this instrument had very good internal consistency reliability. Similar factors emerged in each of the sample sub-groups when factor analyses were performed suggesting that this instrument has good external and construct validities. These factors each had respectable Cronbach alpha coefficients indicating their own internal consistency. The four factors which consistently emerged were Same Sex Responsiveness, Opposite Sex Responsiveness, Previous Month’s Same Sex Responsiveness and Previous Month’s Opposite Sex Responsiveness. The second scale consisted of 16 items and was administered to 646 adolescents, comprising the latter two sub-groups referred to above. A Cronbach alpha coefficient of 0.82 was calculated indicating that this instrument also had very good internal consistency reliability. Once again similar factors with generally good internal consistency emerged in factor analysis suggesting that this too was a valid instrument. The factors that emerged from the second scale were Same Sex Responsiveness, Unattractive Opposite Sex Responsiveness, Attractive Opposite Sex Responsiveness and Attraction. Future developments, adjustments and applications of the instruments as well as implications for the arena of sexual orientation research are discussed. In the light of the dearth of information with regard to the sexual orientations of South African adolescents the current study also briefly explored and presented the sample’s responses in terms of the dimensions of each questionnaire as well as how each emerging factor related to the demographics (education level, gender, sexual orientation self-label and age) of the sample.
- Full Text:
- Date Issued: 2005
Design, evaluation and comparison of evolution and reinforcement learning models
- Authors: Mclean, Clinton Brett
- Date: 2002
- Subjects: Evolutionary computation Neural networks (Computer science) Reinforcement learning
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: vital:4625 , http://hdl.handle.net/10962/d1006493
- Description: This work presents the design, evaluation and comparison of evolution and reinforcement learning models, in isolation and combined in Darwinian and Lamarckian frameworks, with a particular emphasis being placed on their adaptive nature in response to environments that become increasingly unstable. Our ultimate objective is to determine whether hybrid models of evolution and learning can demonstrate adaptive qualities beyond those of such models when applied in isolation. This work demonstrates the limitations of evolution, reinforcement learning and Lamarckian models in dealing with increasingly unstable environments, while noting the effective adaptive nature of a Darwinian model to assimilate increasing levels of instability. This is shown to be a result of the Darwinian evolution model's ability to separate learning at two levels, the population's experience of the environment over the course of many generations and the individual's experience of the environment over the course of its lifetime. Thus, knowledge relating to the general characteristics of the environment over many generations can be maintained in the population's genotypes with phenotype (reinforcement) learning being utilized to adapt a particular agent to the particular characteristics of its environment. Lamarckian evolution, though, is shown to demonstrate adaptive characteristics that are highly effective in response to the stable environments. Selection and reproduction combined with reinforcement learning creates a model that has the ability to utilize useful knowledge produced by reinforcements, as opposed to random mutations, to accelerate the search process. As a result the influence of individual learning on the populations evolution is shown to be more successful when applied in the more direct Lamarckian form. Based on our results demonstrating the success of Lamarckian strategies in stable environments and Darwinian strategies in unstable environments, hybrid Darwinian/Lamarckian models are created with a view towards combining the advantages of both forms of evolution to produce a superior adaptive capability. Our investigation demonstrates that such hybrid models can effectively combine the adaptive advantageous of both Darwinian and Lamarckian evolution to provide a more effective capability of adapting to a range of conditions, from stable to unstable, appropriately adjusting the required degree of inheritance in response to the requirements of the environment.
- Full Text:
- Date Issued: 2002
- Authors: Mclean, Clinton Brett
- Date: 2002
- Subjects: Evolutionary computation Neural networks (Computer science) Reinforcement learning
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: vital:4625 , http://hdl.handle.net/10962/d1006493
- Description: This work presents the design, evaluation and comparison of evolution and reinforcement learning models, in isolation and combined in Darwinian and Lamarckian frameworks, with a particular emphasis being placed on their adaptive nature in response to environments that become increasingly unstable. Our ultimate objective is to determine whether hybrid models of evolution and learning can demonstrate adaptive qualities beyond those of such models when applied in isolation. This work demonstrates the limitations of evolution, reinforcement learning and Lamarckian models in dealing with increasingly unstable environments, while noting the effective adaptive nature of a Darwinian model to assimilate increasing levels of instability. This is shown to be a result of the Darwinian evolution model's ability to separate learning at two levels, the population's experience of the environment over the course of many generations and the individual's experience of the environment over the course of its lifetime. Thus, knowledge relating to the general characteristics of the environment over many generations can be maintained in the population's genotypes with phenotype (reinforcement) learning being utilized to adapt a particular agent to the particular characteristics of its environment. Lamarckian evolution, though, is shown to demonstrate adaptive characteristics that are highly effective in response to the stable environments. Selection and reproduction combined with reinforcement learning creates a model that has the ability to utilize useful knowledge produced by reinforcements, as opposed to random mutations, to accelerate the search process. As a result the influence of individual learning on the populations evolution is shown to be more successful when applied in the more direct Lamarckian form. Based on our results demonstrating the success of Lamarckian strategies in stable environments and Darwinian strategies in unstable environments, hybrid Darwinian/Lamarckian models are created with a view towards combining the advantages of both forms of evolution to produce a superior adaptive capability. Our investigation demonstrates that such hybrid models can effectively combine the adaptive advantageous of both Darwinian and Lamarckian evolution to provide a more effective capability of adapting to a range of conditions, from stable to unstable, appropriately adjusting the required degree of inheritance in response to the requirements of the environment.
- Full Text:
- Date Issued: 2002
Share-net: a case study of environmental education resource material development in a risk society
- Authors: Taylor, Robert James
- Date: 1997
- Subjects: Environmental education Environmental education -- South Africa Environmental education -- Activity programs -- South Africa Environmental education -- South Africa -- Information resources
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1765 , http://hdl.handle.net/10962/d1003650
- Description: This narrative study reviews the development of Share-Net, an informal resource materials network, located within the developing environmental education activities of the Wildlife and Environment Society of South Africa. Historical shaping factors within the Society are discussed and changing views on conservation, environmental education and research are described. Rather than the research process being a utilitarian and outside endeavour for clarifying and monitoring, the research orientation of this study is one of grounded activity within and integrally part of processes of change. Within a developing story of resource materials and workshops, themes are traced and emergent tensions are critically reviewed. Teacher workshops from 1981 until 1995 are analysed and developing orientations are described. Within this review changes are evident from an orientation of 'us' informing 'them' to joint, collaborative endeavours within the development and use of resource materials. The study reviews and illuminates the Share-Net project around questions of project orientation and management and this is done through the narration of case studies. Principles and patterns emerging within these are examined to guide future resource development projects. Popularist notions of networking and structural functionalist notions of social change are also examined. Grand, modernist strategies designed to cause change in others are questioned and the role of small-scale nodes of resource material activity cooperating within an open network are clarified as useful alternatives. Local resourcing centres such as these have proved useful in supporting teachers in the development, use and adaptation of resource materials. The study also examines income and expenditure of the Share-Net project since 1988 to review economic sustainability. A case is made for sustaining the project conceptually and financially through the sales of products and services rather than through external donor sources. Finally the study raises questions and challenges within the project and proposes guiding frameworks for future review, in action, as the story continues.
- Full Text:
- Date Issued: 1997
- Authors: Taylor, Robert James
- Date: 1997
- Subjects: Environmental education Environmental education -- South Africa Environmental education -- Activity programs -- South Africa Environmental education -- South Africa -- Information resources
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1765 , http://hdl.handle.net/10962/d1003650
- Description: This narrative study reviews the development of Share-Net, an informal resource materials network, located within the developing environmental education activities of the Wildlife and Environment Society of South Africa. Historical shaping factors within the Society are discussed and changing views on conservation, environmental education and research are described. Rather than the research process being a utilitarian and outside endeavour for clarifying and monitoring, the research orientation of this study is one of grounded activity within and integrally part of processes of change. Within a developing story of resource materials and workshops, themes are traced and emergent tensions are critically reviewed. Teacher workshops from 1981 until 1995 are analysed and developing orientations are described. Within this review changes are evident from an orientation of 'us' informing 'them' to joint, collaborative endeavours within the development and use of resource materials. The study reviews and illuminates the Share-Net project around questions of project orientation and management and this is done through the narration of case studies. Principles and patterns emerging within these are examined to guide future resource development projects. Popularist notions of networking and structural functionalist notions of social change are also examined. Grand, modernist strategies designed to cause change in others are questioned and the role of small-scale nodes of resource material activity cooperating within an open network are clarified as useful alternatives. Local resourcing centres such as these have proved useful in supporting teachers in the development, use and adaptation of resource materials. The study also examines income and expenditure of the Share-Net project since 1988 to review economic sustainability. A case is made for sustaining the project conceptually and financially through the sales of products and services rather than through external donor sources. Finally the study raises questions and challenges within the project and proposes guiding frameworks for future review, in action, as the story continues.
- Full Text:
- Date Issued: 1997
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