An exploration of the role of uniforms in contributing to the embedding and transmitting of organizational culture
- Authors: Gibson-Tessendorf, Cornel
- Date: 2005
- Subjects: Organizational behavior Corporate culture Clothing and dress -- Social aspects Employees -- Uniform Uniforms
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:1170 , http://hdl.handle.net/10962/d1002786
- Description: Many companies today are using some form of uniforms for employees. This research is an exploration of the role of uniforms in contributing to the embedding and transmitting of organizational culture. Culture is the experiences and common learning of the organization that results in shared values and beliefs. According to Schein (1985: 14) culture has three levels, namely: artifacts, values, and basic underlying assumptions. The first level of the culture consists of the physical constructs of the organization, and therefore includes the uniforms, which is the focus of this study. Schein (1985: 223) further proposes that culture can be embedded and transmitted through various mechanisms. The research was conducted in the constructivist paradigm, at a tertiary institution of higher learning in Eastern Cape, South Africa. To ensure triangulation, three sources of data were used, namely: documentation; observation; and both individual and focus group interviews. The researcher argues that uniforms played a role in the embedding of the sample organization’s three levels of culture, which were expressed in terms of Hofstede’s (1991: 07) culture dimensions. Firstly, the use of the different uniforms by different groups, as well as the ranking indicated by the uniforms, played a role in embedding the high power distance culture. Secondly, the symbolism of security portrayed by the uniform played a role in embedding the high uncertainty avoidance culture. Thirdly, it was found that the uniform created unity amongst groups, resulting in greater expression of collectivism. Fourthly, the use of sensible and practical uniforms plays a role in embedding the feminine culture where competitiveness is avoided and relationships are nurtured. Lastly, the uniform plays a possible role in transforming the culture from short-term to a long-term orientation that focuses on the future.
- Full Text:
- Date Issued: 2005
- Authors: Gibson-Tessendorf, Cornel
- Date: 2005
- Subjects: Organizational behavior Corporate culture Clothing and dress -- Social aspects Employees -- Uniform Uniforms
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:1170 , http://hdl.handle.net/10962/d1002786
- Description: Many companies today are using some form of uniforms for employees. This research is an exploration of the role of uniforms in contributing to the embedding and transmitting of organizational culture. Culture is the experiences and common learning of the organization that results in shared values and beliefs. According to Schein (1985: 14) culture has three levels, namely: artifacts, values, and basic underlying assumptions. The first level of the culture consists of the physical constructs of the organization, and therefore includes the uniforms, which is the focus of this study. Schein (1985: 223) further proposes that culture can be embedded and transmitted through various mechanisms. The research was conducted in the constructivist paradigm, at a tertiary institution of higher learning in Eastern Cape, South Africa. To ensure triangulation, three sources of data were used, namely: documentation; observation; and both individual and focus group interviews. The researcher argues that uniforms played a role in the embedding of the sample organization’s three levels of culture, which were expressed in terms of Hofstede’s (1991: 07) culture dimensions. Firstly, the use of the different uniforms by different groups, as well as the ranking indicated by the uniforms, played a role in embedding the high power distance culture. Secondly, the symbolism of security portrayed by the uniform played a role in embedding the high uncertainty avoidance culture. Thirdly, it was found that the uniform created unity amongst groups, resulting in greater expression of collectivism. Fourthly, the use of sensible and practical uniforms plays a role in embedding the feminine culture where competitiveness is avoided and relationships are nurtured. Lastly, the uniform plays a possible role in transforming the culture from short-term to a long-term orientation that focuses on the future.
- Full Text:
- Date Issued: 2005
A study of Ted Hughes's Birthday letters
- Authors: Highman, Kathryn Barbara
- Date: 2004
- Subjects: Hughes, Ted, 1930-1998 Criticism and interpretation Hughes, Ted, 1930-1998 Birthday Letters
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2193 , http://hdl.handle.net/10962/d1002235
- Description: This thesis focusses on the literary self-reflexivity of Birthday Letters, Ted Hughes's collection of poems addressed to his long-dead first wife, poet Sylvia Plath. By close attention to the language of select poems and a discussion of cross-referencing images and allusions across the volume, and intertextually, I argue that the collection is more self-consciously ordered and designed than the mainly biographical criticism the work has met with suggests. The thesis focusses on the poets' art rather than the biographical context of Birthday Letters, though it does not draw a neat distinction between their lives and their poetry - rather it demonstrates how Birthday Letters itself treats the relationship of art to life thematically. The introduction outlines the context of the volume's genesis and publication and the notions of poetry, myth and drama out of which Hughes works, and introduces the central metaphor of metamorphosis as figured in Ariel's song "Full Fathom Five" from The Tempest, as well as the importance of that play to Plath. Each of the chapters that follow focusses on a cluster of inter-related imagery through a discussion of four or five key poems. Chapter One examines Hughes's portrayal of himself as imprisoned by Plath's poetic portraits, and relates this to the recurring motifs of the snapshot and the Medusa myth. The poems discussed emphasize Hughes's consciousness of the metamorphic and "magical" relationship of art to life. The second chapter discusses Hughes's use of the myth of the labyrinth and the Minotaur, tracing it back to Plath's writings and reading, and pointing out its self-reflexivity: the labyrinth figures Hughes's own loss as well as the labyrinthine nature of writing. The third chapter considers the themes of possession and loss, and how they attach themselves to images of houses and jewels. Possession and loss tum, self-reflexively, upon issues of inheritance and remembrance, notably Hughes's inheritance of Plath's poetic legacy, and his remembrance of her and her poetry through his own poetry. The conclusion pursues connections between the observations made in the separate chapters, outlining the larger context out of which the poems emerge, and returning to the trope of metamorphosis as figured in "Full Fathom Five"
- Full Text:
- Date Issued: 2004
- Authors: Highman, Kathryn Barbara
- Date: 2004
- Subjects: Hughes, Ted, 1930-1998 Criticism and interpretation Hughes, Ted, 1930-1998 Birthday Letters
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2193 , http://hdl.handle.net/10962/d1002235
- Description: This thesis focusses on the literary self-reflexivity of Birthday Letters, Ted Hughes's collection of poems addressed to his long-dead first wife, poet Sylvia Plath. By close attention to the language of select poems and a discussion of cross-referencing images and allusions across the volume, and intertextually, I argue that the collection is more self-consciously ordered and designed than the mainly biographical criticism the work has met with suggests. The thesis focusses on the poets' art rather than the biographical context of Birthday Letters, though it does not draw a neat distinction between their lives and their poetry - rather it demonstrates how Birthday Letters itself treats the relationship of art to life thematically. The introduction outlines the context of the volume's genesis and publication and the notions of poetry, myth and drama out of which Hughes works, and introduces the central metaphor of metamorphosis as figured in Ariel's song "Full Fathom Five" from The Tempest, as well as the importance of that play to Plath. Each of the chapters that follow focusses on a cluster of inter-related imagery through a discussion of four or five key poems. Chapter One examines Hughes's portrayal of himself as imprisoned by Plath's poetic portraits, and relates this to the recurring motifs of the snapshot and the Medusa myth. The poems discussed emphasize Hughes's consciousness of the metamorphic and "magical" relationship of art to life. The second chapter discusses Hughes's use of the myth of the labyrinth and the Minotaur, tracing it back to Plath's writings and reading, and pointing out its self-reflexivity: the labyrinth figures Hughes's own loss as well as the labyrinthine nature of writing. The third chapter considers the themes of possession and loss, and how they attach themselves to images of houses and jewels. Possession and loss tum, self-reflexively, upon issues of inheritance and remembrance, notably Hughes's inheritance of Plath's poetic legacy, and his remembrance of her and her poetry through his own poetry. The conclusion pursues connections between the observations made in the separate chapters, outlining the larger context out of which the poems emerge, and returning to the trope of metamorphosis as figured in "Full Fathom Five"
- Full Text:
- Date Issued: 2004
On the use of metabolic rate measurements to assess the stress response in juvenile spotted grunter, Pomadasys commersonnii (Haemulidae, Pisces)
- Authors: Radull, John
- Date: 2003
- Subjects: Fishes -- Metabolism Fishes -- Physiology Pomadasys -- Physiology Grunts (Fishes) -- Physiology Stress (Psychology) Stress (Physiology)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5350 , http://hdl.handle.net/10962/d1007564
- Description: Quantitication of stress requires the use of a stress indicator that is easy to measure, and which can be readily interpreted in terms of the potential long-term effects to an organism. This study evaluates the suitability of metabolic rate as an indicator of the stress response in fish. By comparing the metabolic with the cortisol stress response, the most commonly used indicator of stress in fish, it was possible to assess the suitability of metabolic rate as a stress indicator. Changes in metabolic rate were used to predict the long-term effects of transport-related stressors. This study also detennined the baseline metabolic rates of the tish. The standard and the active metabolic rates of juvenile P. cummersonnii were 0.16 ± 0.02 (mean ± S.D, n = 6) mg O₂g⁻¹h⁻¹, and 0.56 ± 0.04 mg O₂g⁻¹h⁻¹, respectively, whereas the routine metabolic rate for the fish was 0.25 ± 0.03 mg O₂g⁻¹h¹. The relationship between metabolic rate and body weight was described by the equation ϺO₂ = 0.64 W⁻°·³⁸. 24-h oxygen consumption measurements showed that juvenile P. commersonnii exhibited diel rhythmicity in oxygen consumption rate, the higher rates occurring at night and the lower rates during the daytime. The higher nocturnal metabolic activity may have been due to increased activity induced by an endogenous rhythm related to feeding. Diel rhythmicity has direct implications for the measurement of baseline metabolic rates since it could result in overestimation or underestimation of these rates. 24-h continuous oxygen consumption measurements enabled the detection of the rhythmicity in oxygen consumption rate, and thereby ensured a greater degree of accuracy in the estimation of these parameters. The metabolic stress response in juvenile P. commersonnii was best described by the equation, y = -0.0013 x² + 0.0364 x ÷ 0.3052, where x = time after application of stressor, and y = oxygen consumption rate. Using the derivative of this equation, the metabolic stress response was estimated to peak approximately 14 min after application of a simulated capture and handling stressor. Oxygen consumption increased by about 300 % as a result of the stress. Approximately 15 min after application of a similar stressor, plasma cortisol levels in stressed fish was 200 % higher than baseline levels. However, cortisol levels in fish sampled 30 min after the disturbance was similar to the baseline cortisol levels, indicating that full recovery had occurred. Although the patterns in the metabolic and cortisol stress responses were similar, metabolic rate could be measured continuously, thereby ensuring accurate interpretation of the data. Furthermore, increases in metabolic rate during the stress response are a culmination of physiological events from the primary to the tertiary levels of biological organization and are, therefore, easier to interpret in terms of long-term effects on the fish. Different transportation procedures elicited variable degrees of stress in juvenile P. commersonnii. The cost of metabolism attributed to the effects of capture and handling was twice as much as that attributed to acute temperature elevation. Acute temperature decrease resulted in a signiticant reduction in the oxygen consumption rate (ANOVA, P < 0.05). Oxygen consumption by the fish was not affected by fish density (ANOVA: F = 2.002, P = 0.5), or by oxygen depletion at dissolved oxygen concentrations above the critical level. Below this level, however, oxygen consumption decreased linearly with further decrease in dissolved oxygen concentration. These results showed that the highest energetic cost to juvenile P. commersonnii was incurred as a result of capture and handling. The results also showed that by subjecting fish to different stressors, it was possible to categorize them according to their relative metabolic costs to the fish. At 25º C, the effective concentration of 2-phenoxyethanol to fully anaesthetize (Stage IV, McFarland 1960) juvenile P. commersonnii was 0.4 ml l⁻¹ and the most appropriate concentration for deep sedation (Stage II, McFarland 1960) of the fish for at least 24 h was 0.2 ml l⁻¹. A maximum of 3 minutes was required by the fish to recover from the effects of the anaesthetic. There was no correlation between fish weight and the rate of induction of anaesthesia (r² = 0.001, p = 0.3). At the peak of the metabolic stress response, oxygen consumption was twice as high in the un-anaesthetized fish compared to the fish anaesthetized after the application of the simulated capture and handling stressor, suggesting that anaesthetization with 2-phenoxyethanol may have reduced the effect of the disturbance on the fish. Similar oxygen consumption rates for the fish anaesthetized prior to capture and the non-stressed fish suggested that the increases in metabolic rate could be linked to the struggling associated with attempts by fish to escape from the perceived stressor. Anaesthetization of juvenile P. commersonnii with 0.3 ml l⁻¹ 2-phenoxyethanol resulted in a more than 200 % increase in plasma cortisol concentration. The elevated levels of plasma cortisol in the anaesthetized fish suggested a manifestation of 2-phenoxyethanol as a stressor. At the time of capture, cortisol levels in fish that were anaesthetized prior to capture were the same as those measured in the disturbed fish at the peak of the stress response (ANOVA, p = 0.95), suggesting that the anaesthetized fish were already experiencing considerable stress at the time they were captured. Undisturbed juvenile P. commersonnii that were anaesthetized for 1 h also had cortisol levels that were five times higher than those measured in undisturbed-unanaesthetized fish, indicating that the duration of exposure to the anaesthetic had a significant effect on plasma cortisol levels. The results presented in this study demonstrate the usefulness of metabolic rate as an indicator of acute stress in fish. This was achieved by comparing the metabolic and the cortisol stress responses. The ease and accuracy with which oxygen consumption of fish could be measured made it possible to measure the stress response more accurately than by plasma cortisol concentration. It was also possible to monitor metabolic rate continuously over a long duration using polarographic oxygen sensors, thus enabling a better evaluation of the stress response. These results, thus, suggest that metabolic rate measurements could be a more practical way to quantify the effects of acute stressors on juvenile fishes. By detailing the profile of the metabolic stress response in P. commersonnii, this study makes a contribution towards understanding the physiological effects of stress in fishes. The study also contributes towards the quantification of baseline metabolic rates of this species under captivity. This study also contributes towards understanding the effects of 2-phenoxyethanol on the stress physiology of fish. By anaesthetizing fish under different conditions of stress, it was possible to evaluate the effect of 2-phenoxyethanol on the metabolic stress response. The ability of 2-phenoxyethanol to reduce physical activity of the fish, and thereby reduce the impact of acute stress on the metabolic stress response, makes it a good agent for the mitigation of stress during the capture and handling of fish. However, the increase in plasma cortisol concentration during prolonged anaesthetization using this drug suggests that the anaesthetic might be a stressor to fish and may, therefore, not be suitable for long-term sedation.
- Full Text:
- Date Issued: 2003
- Authors: Radull, John
- Date: 2003
- Subjects: Fishes -- Metabolism Fishes -- Physiology Pomadasys -- Physiology Grunts (Fishes) -- Physiology Stress (Psychology) Stress (Physiology)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5350 , http://hdl.handle.net/10962/d1007564
- Description: Quantitication of stress requires the use of a stress indicator that is easy to measure, and which can be readily interpreted in terms of the potential long-term effects to an organism. This study evaluates the suitability of metabolic rate as an indicator of the stress response in fish. By comparing the metabolic with the cortisol stress response, the most commonly used indicator of stress in fish, it was possible to assess the suitability of metabolic rate as a stress indicator. Changes in metabolic rate were used to predict the long-term effects of transport-related stressors. This study also detennined the baseline metabolic rates of the tish. The standard and the active metabolic rates of juvenile P. cummersonnii were 0.16 ± 0.02 (mean ± S.D, n = 6) mg O₂g⁻¹h⁻¹, and 0.56 ± 0.04 mg O₂g⁻¹h⁻¹, respectively, whereas the routine metabolic rate for the fish was 0.25 ± 0.03 mg O₂g⁻¹h¹. The relationship between metabolic rate and body weight was described by the equation ϺO₂ = 0.64 W⁻°·³⁸. 24-h oxygen consumption measurements showed that juvenile P. commersonnii exhibited diel rhythmicity in oxygen consumption rate, the higher rates occurring at night and the lower rates during the daytime. The higher nocturnal metabolic activity may have been due to increased activity induced by an endogenous rhythm related to feeding. Diel rhythmicity has direct implications for the measurement of baseline metabolic rates since it could result in overestimation or underestimation of these rates. 24-h continuous oxygen consumption measurements enabled the detection of the rhythmicity in oxygen consumption rate, and thereby ensured a greater degree of accuracy in the estimation of these parameters. The metabolic stress response in juvenile P. commersonnii was best described by the equation, y = -0.0013 x² + 0.0364 x ÷ 0.3052, where x = time after application of stressor, and y = oxygen consumption rate. Using the derivative of this equation, the metabolic stress response was estimated to peak approximately 14 min after application of a simulated capture and handling stressor. Oxygen consumption increased by about 300 % as a result of the stress. Approximately 15 min after application of a similar stressor, plasma cortisol levels in stressed fish was 200 % higher than baseline levels. However, cortisol levels in fish sampled 30 min after the disturbance was similar to the baseline cortisol levels, indicating that full recovery had occurred. Although the patterns in the metabolic and cortisol stress responses were similar, metabolic rate could be measured continuously, thereby ensuring accurate interpretation of the data. Furthermore, increases in metabolic rate during the stress response are a culmination of physiological events from the primary to the tertiary levels of biological organization and are, therefore, easier to interpret in terms of long-term effects on the fish. Different transportation procedures elicited variable degrees of stress in juvenile P. commersonnii. The cost of metabolism attributed to the effects of capture and handling was twice as much as that attributed to acute temperature elevation. Acute temperature decrease resulted in a signiticant reduction in the oxygen consumption rate (ANOVA, P < 0.05). Oxygen consumption by the fish was not affected by fish density (ANOVA: F = 2.002, P = 0.5), or by oxygen depletion at dissolved oxygen concentrations above the critical level. Below this level, however, oxygen consumption decreased linearly with further decrease in dissolved oxygen concentration. These results showed that the highest energetic cost to juvenile P. commersonnii was incurred as a result of capture and handling. The results also showed that by subjecting fish to different stressors, it was possible to categorize them according to their relative metabolic costs to the fish. At 25º C, the effective concentration of 2-phenoxyethanol to fully anaesthetize (Stage IV, McFarland 1960) juvenile P. commersonnii was 0.4 ml l⁻¹ and the most appropriate concentration for deep sedation (Stage II, McFarland 1960) of the fish for at least 24 h was 0.2 ml l⁻¹. A maximum of 3 minutes was required by the fish to recover from the effects of the anaesthetic. There was no correlation between fish weight and the rate of induction of anaesthesia (r² = 0.001, p = 0.3). At the peak of the metabolic stress response, oxygen consumption was twice as high in the un-anaesthetized fish compared to the fish anaesthetized after the application of the simulated capture and handling stressor, suggesting that anaesthetization with 2-phenoxyethanol may have reduced the effect of the disturbance on the fish. Similar oxygen consumption rates for the fish anaesthetized prior to capture and the non-stressed fish suggested that the increases in metabolic rate could be linked to the struggling associated with attempts by fish to escape from the perceived stressor. Anaesthetization of juvenile P. commersonnii with 0.3 ml l⁻¹ 2-phenoxyethanol resulted in a more than 200 % increase in plasma cortisol concentration. The elevated levels of plasma cortisol in the anaesthetized fish suggested a manifestation of 2-phenoxyethanol as a stressor. At the time of capture, cortisol levels in fish that were anaesthetized prior to capture were the same as those measured in the disturbed fish at the peak of the stress response (ANOVA, p = 0.95), suggesting that the anaesthetized fish were already experiencing considerable stress at the time they were captured. Undisturbed juvenile P. commersonnii that were anaesthetized for 1 h also had cortisol levels that were five times higher than those measured in undisturbed-unanaesthetized fish, indicating that the duration of exposure to the anaesthetic had a significant effect on plasma cortisol levels. The results presented in this study demonstrate the usefulness of metabolic rate as an indicator of acute stress in fish. This was achieved by comparing the metabolic and the cortisol stress responses. The ease and accuracy with which oxygen consumption of fish could be measured made it possible to measure the stress response more accurately than by plasma cortisol concentration. It was also possible to monitor metabolic rate continuously over a long duration using polarographic oxygen sensors, thus enabling a better evaluation of the stress response. These results, thus, suggest that metabolic rate measurements could be a more practical way to quantify the effects of acute stressors on juvenile fishes. By detailing the profile of the metabolic stress response in P. commersonnii, this study makes a contribution towards understanding the physiological effects of stress in fishes. The study also contributes towards the quantification of baseline metabolic rates of this species under captivity. This study also contributes towards understanding the effects of 2-phenoxyethanol on the stress physiology of fish. By anaesthetizing fish under different conditions of stress, it was possible to evaluate the effect of 2-phenoxyethanol on the metabolic stress response. The ability of 2-phenoxyethanol to reduce physical activity of the fish, and thereby reduce the impact of acute stress on the metabolic stress response, makes it a good agent for the mitigation of stress during the capture and handling of fish. However, the increase in plasma cortisol concentration during prolonged anaesthetization using this drug suggests that the anaesthetic might be a stressor to fish and may, therefore, not be suitable for long-term sedation.
- Full Text:
- Date Issued: 2003
The electrochemical hydroxylation of aromatic substrates
- Authors: Rautenbach, Daniel
- Date: 2002
- Subjects: Aromatic compounds , Hydroxylation
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10959 , http://hdl.handle.net/10948/94 , Aromatic compounds , Hydroxylation
- Description: The electrochemical hydroxylation of aromatic substrates was investigated in some detail, with the view to develop a method, which could produce dihydroxybenzenes in acceptable yields. Of particular interest was the selectivity and yield of the 1,4-dihydroxybenzenes. Two distinctly different methods were investigated in order to achieve this goal, acyloxylation and direct electrochemical hydroxylation. Acyloxylation is the process where radical cations generated at the anode undergoes nucleophilic attack by acetate anions. The resulting aromatic acetates so produced can then be hydrolysed to the phenolic compounds. Two nucleophile systems were considered in the investigation, acetates (acetoxylation) and trifluoro-acetates (trifluoro-acetoxylation). These investigations were conducted under a variety of conditions using phenol and phenyl acetate as starting materials. From the results it was, however, concluded that the acetoxylation of these aromatic compounds occurs in unacceptable product and current yields. Trifluoro-acetoxylation on the other hand showed promise, but due to the nature and cost of the reagents it was deemed to be an impractical process. Direct electrochemical hydroxylation: in which the radical cations produced at the anode undergoes nucleophilic attack by water producing the corresponding dihydroxybenzenes. These dihydroxybenzenes are then further oxidised to the benzoquinones, which then undergo reduction at the cathode in order to produce the corresponding dihydroxybenzene. In this process phenol, 2-tert-butylphenol and 2,6-di-tert-butylphenol were investigated as substrates. The results indicated that the yield towards the 1,4-dihdroxybenzenes increased as the degree of substitution on the ring increased.
- Full Text:
- Date Issued: 2002
- Authors: Rautenbach, Daniel
- Date: 2002
- Subjects: Aromatic compounds , Hydroxylation
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10959 , http://hdl.handle.net/10948/94 , Aromatic compounds , Hydroxylation
- Description: The electrochemical hydroxylation of aromatic substrates was investigated in some detail, with the view to develop a method, which could produce dihydroxybenzenes in acceptable yields. Of particular interest was the selectivity and yield of the 1,4-dihydroxybenzenes. Two distinctly different methods were investigated in order to achieve this goal, acyloxylation and direct electrochemical hydroxylation. Acyloxylation is the process where radical cations generated at the anode undergoes nucleophilic attack by acetate anions. The resulting aromatic acetates so produced can then be hydrolysed to the phenolic compounds. Two nucleophile systems were considered in the investigation, acetates (acetoxylation) and trifluoro-acetates (trifluoro-acetoxylation). These investigations were conducted under a variety of conditions using phenol and phenyl acetate as starting materials. From the results it was, however, concluded that the acetoxylation of these aromatic compounds occurs in unacceptable product and current yields. Trifluoro-acetoxylation on the other hand showed promise, but due to the nature and cost of the reagents it was deemed to be an impractical process. Direct electrochemical hydroxylation: in which the radical cations produced at the anode undergoes nucleophilic attack by water producing the corresponding dihydroxybenzenes. These dihydroxybenzenes are then further oxidised to the benzoquinones, which then undergo reduction at the cathode in order to produce the corresponding dihydroxybenzene. In this process phenol, 2-tert-butylphenol and 2,6-di-tert-butylphenol were investigated as substrates. The results indicated that the yield towards the 1,4-dihdroxybenzenes increased as the degree of substitution on the ring increased.
- Full Text:
- Date Issued: 2002
The implications of the introduction of outcomes based education in the natural sciences curriculum at Cape College of Education: the assessment of perceptions of squatter camp teachers in Khayelitsha towards the outcomes based education
- Authors: Booi, Kwanele
- Date: 2000
- Subjects: Competency-based education -- South Africa Competency-based education -- Evaluation Competency-based education -- South Africa -- Khayelitsha -- Evaluation Physical sciences -- Study and teaching -- Evaluation Life sciences -- Study and teaching -- Evaluation Cape College of Education
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1569 , http://hdl.handle.net/10962/d1003451
- Description: 1. This pilot study is a survey of practices of natural sciences educators at Cape College of Education to establish if they reflect the conceptual development, development of skills, change of attitudes and values that are the pillars of the Outcomes Based Education (OBE). Their approaches of lecturing have been assessed to determine if they incorporate investigative approaches based on social constructivism, the theory underpinning Curriculum 2005. The status of science education in the college has been analyzed to establish whether the curriculum can adapt itself to the specifications of the new curriculum. It has been concluded that the educators at Cape College of Education need to be empowered about strategies that will help them function along the principles embracing Curriculum 2005 specifications. The educators have shown not to be ready to practice social constructivism and the assessment strategies incorporated in their programmes do not embrace a variety of approaches that will enable their learners to develop conceptually, skill wise and enable them to develop change in attitudes and values. Investigative approaches to practical work appear to be lacking in the college teaching/learning and this also indicates that Curriculum 2005 will take time to be properly implemented at Cape College of Education. 2. This study is based on the practices of science educators in the squatter-camp school in Khayelitsha, a densely populated area for blacks near Cape Town. Teachers at Vuselela primary school were interviewed about their teaching assessment strategies to establish whether they incorporate a learner centred approach, which is the necessity for the Outcomes Based Education approach. Also some of the lessons they taught were observed in order to find out whether they validate what transpired from the interviews through a process of triangulation. It has become evident that the teachers are to some extent aware of the changes the education system is going through in South Africa. It also became clear from the study that the teachers are still lacking expertise as to how to practice along the lines of Curriculum 2005, the South African version of Outcomes Based Education (OBE). They also showed that they are keen to learn and practice OBE even though more opportunities need to be created for their epistemological empowerment as well as empowerment on the content of science.
- Full Text:
- Date Issued: 2000
- Authors: Booi, Kwanele
- Date: 2000
- Subjects: Competency-based education -- South Africa Competency-based education -- Evaluation Competency-based education -- South Africa -- Khayelitsha -- Evaluation Physical sciences -- Study and teaching -- Evaluation Life sciences -- Study and teaching -- Evaluation Cape College of Education
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1569 , http://hdl.handle.net/10962/d1003451
- Description: 1. This pilot study is a survey of practices of natural sciences educators at Cape College of Education to establish if they reflect the conceptual development, development of skills, change of attitudes and values that are the pillars of the Outcomes Based Education (OBE). Their approaches of lecturing have been assessed to determine if they incorporate investigative approaches based on social constructivism, the theory underpinning Curriculum 2005. The status of science education in the college has been analyzed to establish whether the curriculum can adapt itself to the specifications of the new curriculum. It has been concluded that the educators at Cape College of Education need to be empowered about strategies that will help them function along the principles embracing Curriculum 2005 specifications. The educators have shown not to be ready to practice social constructivism and the assessment strategies incorporated in their programmes do not embrace a variety of approaches that will enable their learners to develop conceptually, skill wise and enable them to develop change in attitudes and values. Investigative approaches to practical work appear to be lacking in the college teaching/learning and this also indicates that Curriculum 2005 will take time to be properly implemented at Cape College of Education. 2. This study is based on the practices of science educators in the squatter-camp school in Khayelitsha, a densely populated area for blacks near Cape Town. Teachers at Vuselela primary school were interviewed about their teaching assessment strategies to establish whether they incorporate a learner centred approach, which is the necessity for the Outcomes Based Education approach. Also some of the lessons they taught were observed in order to find out whether they validate what transpired from the interviews through a process of triangulation. It has become evident that the teachers are to some extent aware of the changes the education system is going through in South Africa. It also became clear from the study that the teachers are still lacking expertise as to how to practice along the lines of Curriculum 2005, the South African version of Outcomes Based Education (OBE). They also showed that they are keen to learn and practice OBE even though more opportunities need to be created for their epistemological empowerment as well as empowerment on the content of science.
- Full Text:
- Date Issued: 2000
Dramatic learning : a case study of theatre for development and environmental education
- Authors: Burt, Jane Caroline
- Date: 1999
- Subjects: Drama in education -- South Africa Environmental education -- Study and teaching (Elementary)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1501 , http://hdl.handle.net/10962/d1003383
- Description: The aim of my research was to introduce drama, in the form of theatre for development processes, to local Grahamstown Primary School teachers, and to work closely with one teacher to explore theatre for development in the classroom, as a means of introducing both environmental education and learner-centred, constructivist teaching methodologies. I started my research by interviewing Primary School principals as well as sending out questionnaires to teachers, to survey their understanding and practice of drama and environmental education in the school curriculum and to invite them to participate in the research project. In collaboration with Educational Drama and Theatre students, I developed two workshops to introduce theatre for development processes such as image theatre and role-play to the teachers. Nine teachers attended this workshop which was video-taped. After the workshop I gave two lessons at a local school, in partnership with a teacher. Throughout this process I kept a research journal. All action components of the research were followed up with individual interviews, group discussions and a focus group. Although the study gave rise to multiple themes, I chose to highlight two: Firstly, Curriculum 2005 advocates a move towards more learner-centred,constructivist and process-orientated pedagogies. All of the participants in this study, including myself, had intentions of adopting a new approach tq education and teaching but found that we often reverted back to earlier learnt roles of product-orientated, text-based, authoritarian approaches to education which we originally had rejected. Secondly, I reflect on how we set out viewing environmental education, education, drama and research as a process and yet all the participants, including myself, continually tried to 'put on' the perfect performance in the form of a drama, a learning experience and research. This project was a participatory research project. The textwork of the research reflects a post-structural orientation. It has been written in the form of a drama to represent the many voices of the participants, but also to question the role of research in society and make research more accessible to non-academic readers. I also intend to perform the research process at a later stage.
- Full Text:
- Date Issued: 1999
- Authors: Burt, Jane Caroline
- Date: 1999
- Subjects: Drama in education -- South Africa Environmental education -- Study and teaching (Elementary)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1501 , http://hdl.handle.net/10962/d1003383
- Description: The aim of my research was to introduce drama, in the form of theatre for development processes, to local Grahamstown Primary School teachers, and to work closely with one teacher to explore theatre for development in the classroom, as a means of introducing both environmental education and learner-centred, constructivist teaching methodologies. I started my research by interviewing Primary School principals as well as sending out questionnaires to teachers, to survey their understanding and practice of drama and environmental education in the school curriculum and to invite them to participate in the research project. In collaboration with Educational Drama and Theatre students, I developed two workshops to introduce theatre for development processes such as image theatre and role-play to the teachers. Nine teachers attended this workshop which was video-taped. After the workshop I gave two lessons at a local school, in partnership with a teacher. Throughout this process I kept a research journal. All action components of the research were followed up with individual interviews, group discussions and a focus group. Although the study gave rise to multiple themes, I chose to highlight two: Firstly, Curriculum 2005 advocates a move towards more learner-centred,constructivist and process-orientated pedagogies. All of the participants in this study, including myself, had intentions of adopting a new approach tq education and teaching but found that we often reverted back to earlier learnt roles of product-orientated, text-based, authoritarian approaches to education which we originally had rejected. Secondly, I reflect on how we set out viewing environmental education, education, drama and research as a process and yet all the participants, including myself, continually tried to 'put on' the perfect performance in the form of a drama, a learning experience and research. This project was a participatory research project. The textwork of the research reflects a post-structural orientation. It has been written in the form of a drama to represent the many voices of the participants, but also to question the role of research in society and make research more accessible to non-academic readers. I also intend to perform the research process at a later stage.
- Full Text:
- Date Issued: 1999
A critical analysis of South African underground comics
- Authors: Breytenbach, Jesse-Ann
- Date: 1996
- Subjects: Underground comic books, strips, etc. -- South Africa -- History and criticism
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2396 , http://hdl.handle.net/10962/d1002192
- Description: In a critical analysis of several independantly produced South African comics of the 1980s and early 1990s, close analysis of the comics leads to an assessment of the artists'intentions and purposes. Discussion of the artists' sources focuses on definitions of different types of comics. What is defined as a comic is usually what has been produced under that definition, and these comics are positioned somewhere between the popular and fine art contexts. As the artists are amateurs, the mechanical structure of comics is exposed through their skill in manipulating, and their initial ignorance of, many comic conventions. By comparison to one another, and to the standard format of commercial comics, some explanation of how a comic works can be reached. The element of closure, bridging the gaps between frames, is unique to comics, and is the most important consideration. Comic artists work with the intangible, creating from static elements an illusion of motion. If the artist deals primarily with what is on the page rather than what is not, the comic remains static. Questions of quality are reliant on the skill with which closure is implemented. The art students who produced these comics are of a generation for whom popular culture is the dominant culture, and they create for an audience of peers. Their cultural milieu is more visual than verbal, and often more media oriented than that of their teachers. They must integrate a fine art training and understanding into the preset rules of a commercial medium. Confronted with the problem of a separation of languages, they evolve a new dialect. Through comparative and critical analyses I will show how this dialect differs from the language of conventional comics, attempting in particular to explain how the mechanics of the cornie medium can limit or expand its communicative potential.
- Full Text:
- Date Issued: 1996
- Authors: Breytenbach, Jesse-Ann
- Date: 1996
- Subjects: Underground comic books, strips, etc. -- South Africa -- History and criticism
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2396 , http://hdl.handle.net/10962/d1002192
- Description: In a critical analysis of several independantly produced South African comics of the 1980s and early 1990s, close analysis of the comics leads to an assessment of the artists'intentions and purposes. Discussion of the artists' sources focuses on definitions of different types of comics. What is defined as a comic is usually what has been produced under that definition, and these comics are positioned somewhere between the popular and fine art contexts. As the artists are amateurs, the mechanical structure of comics is exposed through their skill in manipulating, and their initial ignorance of, many comic conventions. By comparison to one another, and to the standard format of commercial comics, some explanation of how a comic works can be reached. The element of closure, bridging the gaps between frames, is unique to comics, and is the most important consideration. Comic artists work with the intangible, creating from static elements an illusion of motion. If the artist deals primarily with what is on the page rather than what is not, the comic remains static. Questions of quality are reliant on the skill with which closure is implemented. The art students who produced these comics are of a generation for whom popular culture is the dominant culture, and they create for an audience of peers. Their cultural milieu is more visual than verbal, and often more media oriented than that of their teachers. They must integrate a fine art training and understanding into the preset rules of a commercial medium. Confronted with the problem of a separation of languages, they evolve a new dialect. Through comparative and critical analyses I will show how this dialect differs from the language of conventional comics, attempting in particular to explain how the mechanics of the cornie medium can limit or expand its communicative potential.
- Full Text:
- Date Issued: 1996
Planning in Ciskei secondary schools with special reference to managerial teams
- Authors: Magqaza, Ocean Bungani
- Date: 1994
- Subjects: Curriculum planning -- South Africa -- Ciskei Educational planning -- South Africa -- Ciskei Teaching teams School management and organization
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1706 , http://hdl.handle.net/10962/d1003589
- Description: Educational leadership and management is a very wide field of study with interdependent components that should form a chain reaction in order to bring about effective management. This study attempts to investigate planning in schools which is one of the educational leadership and management components or functions. Very little research work has been done on educational planning in the Ciskei schools. This is a shortcoming since the number of secondary schools has mushroomed in the late twentieth century. The Ciskei educational managers and parents need to know and take note of the possible situations in the various schools. This is opportune time, particularly that recent events, i.e. students' demands and strikes, are drawing parents closer to the education of their children. The researcher's experience of inspecting school administration since 1990 has reinforced his conviction that the managerial teams in the Ciskei secondary schools have little knowledge of management, and of planning in particular. Although the investigation is into secondary school administration, it is also pertinent to primary school planning. Management, i.e. school year-planning, control of work, staff development, appointment of teachers, policy governing students and teachers are discussed at length . Joint planning, i.e. a participative or consultative approach, and advance planning, are investigated in relation to the school year-programme. The existence of statutory bodies in the various schools is assessed in order to test parents' involvement in the education of their children. School tours are discussed in relation to students' involvement in the school activities. The analysis of the results highlights areas that require attention, and the recommendations given address the controversial issues in planning in the various schools.
- Full Text:
- Date Issued: 1994
- Authors: Magqaza, Ocean Bungani
- Date: 1994
- Subjects: Curriculum planning -- South Africa -- Ciskei Educational planning -- South Africa -- Ciskei Teaching teams School management and organization
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1706 , http://hdl.handle.net/10962/d1003589
- Description: Educational leadership and management is a very wide field of study with interdependent components that should form a chain reaction in order to bring about effective management. This study attempts to investigate planning in schools which is one of the educational leadership and management components or functions. Very little research work has been done on educational planning in the Ciskei schools. This is a shortcoming since the number of secondary schools has mushroomed in the late twentieth century. The Ciskei educational managers and parents need to know and take note of the possible situations in the various schools. This is opportune time, particularly that recent events, i.e. students' demands and strikes, are drawing parents closer to the education of their children. The researcher's experience of inspecting school administration since 1990 has reinforced his conviction that the managerial teams in the Ciskei secondary schools have little knowledge of management, and of planning in particular. Although the investigation is into secondary school administration, it is also pertinent to primary school planning. Management, i.e. school year-planning, control of work, staff development, appointment of teachers, policy governing students and teachers are discussed at length . Joint planning, i.e. a participative or consultative approach, and advance planning, are investigated in relation to the school year-programme. The existence of statutory bodies in the various schools is assessed in order to test parents' involvement in the education of their children. School tours are discussed in relation to students' involvement in the school activities. The analysis of the results highlights areas that require attention, and the recommendations given address the controversial issues in planning in the various schools.
- Full Text:
- Date Issued: 1994
Aspects of the biology and ecology of the South African abalone Haliotis midae Linnaeus, 1758 (Mollusca Gastropoda) along the eastern Cape and Ciskei coast
- Authors: Wood, A D (Aidan David)
- Date: 1993
- Subjects: Abalones -- South Africa , Abalones -- Ecology , Abalones -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5220 , http://hdl.handle.net/10962/d1005063
- Description: The South African abalone Haliotis midae Linnaeus, 1758, is an important commercial, recreational and aquaculture mollusc species. It is the largest of the six haliotid species found in South African waters and has the second largest distributional range aside from Haliotis spadicea which is widely exploited by rock and surf anglers as bait. Analysis of population structure at Great Fish Point revealed that H. midae exhibited a high degree of microhabitat specificity, and that while dietary habits played a role in habitat selection, it was ultimately the activities of predators which confined size classes to particular niches and restricted all animals to nocturnal activities. Large (> 100 mm SL) exposed animals relied on shell thickness and adhesion to combat predators, while small (> 45 mm SL) sub-boulder animals and medium sized (50 - 95 mm SL) animals relied on their cryptic microhabitats and the protective spine canopies of co-resident urchins (Parechinus angulosus) for daytime protection. Populations of H. midae were discontinuously distributed along the coast, occupying small isolated reefs which offered a suitable array of microhabitats and a good food supply. They mostly inhabited shallow intertidal and subtidal reefs, but were occasionally encountered on deeper subtidal reefs at 4 - 5 meters. Mean length- and width-at-age were determined from growth rings composed of alternate conchiolin (dark) and aragonite (white) bands in the internal nacreous shell layer. Growth was described by the Special Von Bertalanffy growth equation: Lt(mm) = 176.998918 (1 - e⁻°·²⁴²⁴¹⁹⁽t ⁺ °·⁴⁹⁵⁴⁹⁴⁾) Wt(mm) = 159.705689 (1 - e⁻°·¹⁹⁵⁴³⁹⁽t ⁺ °·²¹¹⁶⁾) The ageing technique used was validated for animals from Great Fish Point and Mgwalana using independent tag-return data. The same data provided evidence that growth rates varied between animals from Great Fish Point and Bird Island. The growth data also showed that H. midae exhibited a high degree of individual variation in growth rate. Males and females exhibited similar growth rates. Exposed large animals showed a preference for red seaweeds, in particular Plocamium corallorhiza and Hypnea spicifera, while small sub-boulder cryptic animals included larger proportions of brown (Ralfsia expansa) and green (VIva spp.) algae in their diets. Exposed individuals also exhibited a higher degree of selectivity towards prey items, but in general, stomach contents reflected the most abundant seaweed types. Both drift and attached algal species were utilized by H. midae which was a nocturnal feeder. Pigments from red algae were incorporated into the shell layers giving the shells a pink or brick red colour. Haliotis midae is a dioecious broadcast spawner. Gonad Bulk Indices in combination with detailed histological examination of gonads showed that individuals were iteroparous, asynchronous spawners and that the breeding season extended from March through to October, although the peak spawning activity was between April and June. Males and females can spawn partially, totally or not at all, with atresia of residual gametes occurring after spawning. There is no resting stage, and gametogenesis is initiated directly after spawning. The structure of the ovary and testis and the process of gametogenesis is typical of haliotid species. AI: 1 sex ratio was observed from all populations studied. Sexual maturity was first attained in the 40 - 59 mm SL size class, although evidence for the smallest size at first spawning was recorded at 54.6 mm SL for females and 69 mm SL for males. Sizes at 50% sexual maturity were 72.5 mm SL (52.8 mm SW) at Great Fish Point, 72.5 mm SL (57.4 mm SW) at Mgwalana, 73.7 mm SL (51.2 mm SW) at Cape Recife, and 73.5 mm SL (53.8 mm SW) at Kelly's Beach. Haliotis midae was typically highly fecund, although a high degree of variation resulting in poor relationships between fecundity/shell length and gonad weight/shell length. The relationship between fecundity and gonad weight was linear. In the Eastern Cape, H. midae possessed a faster growth rate, smaller size at sexual maturity, smaller maximum size and lower longevity when compared to con specifics in Western Cape waters. A smaller minimum legal size of 93 mm SW is proposed for Eastern Cape animals and it is suggested that the closed season be moved to the peak spawning period between April and June. The benefit of a closed season during the spawning period is questioned, and the feasibility of closed areas as a management option for H. midae in the Eastern Cape is discussed.
- Full Text:
- Date Issued: 1993
- Authors: Wood, A D (Aidan David)
- Date: 1993
- Subjects: Abalones -- South Africa , Abalones -- Ecology , Abalones -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5220 , http://hdl.handle.net/10962/d1005063
- Description: The South African abalone Haliotis midae Linnaeus, 1758, is an important commercial, recreational and aquaculture mollusc species. It is the largest of the six haliotid species found in South African waters and has the second largest distributional range aside from Haliotis spadicea which is widely exploited by rock and surf anglers as bait. Analysis of population structure at Great Fish Point revealed that H. midae exhibited a high degree of microhabitat specificity, and that while dietary habits played a role in habitat selection, it was ultimately the activities of predators which confined size classes to particular niches and restricted all animals to nocturnal activities. Large (> 100 mm SL) exposed animals relied on shell thickness and adhesion to combat predators, while small (> 45 mm SL) sub-boulder animals and medium sized (50 - 95 mm SL) animals relied on their cryptic microhabitats and the protective spine canopies of co-resident urchins (Parechinus angulosus) for daytime protection. Populations of H. midae were discontinuously distributed along the coast, occupying small isolated reefs which offered a suitable array of microhabitats and a good food supply. They mostly inhabited shallow intertidal and subtidal reefs, but were occasionally encountered on deeper subtidal reefs at 4 - 5 meters. Mean length- and width-at-age were determined from growth rings composed of alternate conchiolin (dark) and aragonite (white) bands in the internal nacreous shell layer. Growth was described by the Special Von Bertalanffy growth equation: Lt(mm) = 176.998918 (1 - e⁻°·²⁴²⁴¹⁹⁽t ⁺ °·⁴⁹⁵⁴⁹⁴⁾) Wt(mm) = 159.705689 (1 - e⁻°·¹⁹⁵⁴³⁹⁽t ⁺ °·²¹¹⁶⁾) The ageing technique used was validated for animals from Great Fish Point and Mgwalana using independent tag-return data. The same data provided evidence that growth rates varied between animals from Great Fish Point and Bird Island. The growth data also showed that H. midae exhibited a high degree of individual variation in growth rate. Males and females exhibited similar growth rates. Exposed large animals showed a preference for red seaweeds, in particular Plocamium corallorhiza and Hypnea spicifera, while small sub-boulder cryptic animals included larger proportions of brown (Ralfsia expansa) and green (VIva spp.) algae in their diets. Exposed individuals also exhibited a higher degree of selectivity towards prey items, but in general, stomach contents reflected the most abundant seaweed types. Both drift and attached algal species were utilized by H. midae which was a nocturnal feeder. Pigments from red algae were incorporated into the shell layers giving the shells a pink or brick red colour. Haliotis midae is a dioecious broadcast spawner. Gonad Bulk Indices in combination with detailed histological examination of gonads showed that individuals were iteroparous, asynchronous spawners and that the breeding season extended from March through to October, although the peak spawning activity was between April and June. Males and females can spawn partially, totally or not at all, with atresia of residual gametes occurring after spawning. There is no resting stage, and gametogenesis is initiated directly after spawning. The structure of the ovary and testis and the process of gametogenesis is typical of haliotid species. AI: 1 sex ratio was observed from all populations studied. Sexual maturity was first attained in the 40 - 59 mm SL size class, although evidence for the smallest size at first spawning was recorded at 54.6 mm SL for females and 69 mm SL for males. Sizes at 50% sexual maturity were 72.5 mm SL (52.8 mm SW) at Great Fish Point, 72.5 mm SL (57.4 mm SW) at Mgwalana, 73.7 mm SL (51.2 mm SW) at Cape Recife, and 73.5 mm SL (53.8 mm SW) at Kelly's Beach. Haliotis midae was typically highly fecund, although a high degree of variation resulting in poor relationships between fecundity/shell length and gonad weight/shell length. The relationship between fecundity and gonad weight was linear. In the Eastern Cape, H. midae possessed a faster growth rate, smaller size at sexual maturity, smaller maximum size and lower longevity when compared to con specifics in Western Cape waters. A smaller minimum legal size of 93 mm SW is proposed for Eastern Cape animals and it is suggested that the closed season be moved to the peak spawning period between April and June. The benefit of a closed season during the spawning period is questioned, and the feasibility of closed areas as a management option for H. midae in the Eastern Cape is discussed.
- Full Text:
- Date Issued: 1993
Insecticide resistance in the blue tick, Boophilus Decoloratus Koch, in South Africa
- Authors: Whitehead, G B
- Date: 1960
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5897 , http://hdl.handle.net/10962/d1013426
- Description: The work described in this dissertation was undertaken in an attempt to obtain a better understanding of the causes and relationships of insecticide resistance in Blue Tick, Boophilus decoloratus Koch, which has become an acute problem in some localities of the country. The work was undertaken at the Research Department of African Explosives and Chemical Industries Limited over a period of six years from 1953 to 1958. An attempt has been made to keep up to date with the published literature on the various aspects of these investigations up until the end of 1958. Information gained from the literature subsequent to end of 1958 has been made use of but it has not been possible for a number of reasons to follow all recent developments in the various aspects of insecticide resistance published during 1959. In the execution of this work assistance has been obtained from colleagues better equipped in the field of organic chemistry, biochemistry and statistics, than the author. Where information so gained has been used it has been duly acknowledged. Considerable assistance was rendered by laboratory assistants who were responsible for performing the considerable amount of routine collection, breeding and testing of the biological material. The blue tick is not a convenient experimental organism for studies on insecticide resistance. Even with the best facilities the tick cannot be bred satisfactorily and in consequence all supplies had to be collected from naturally-occurring populations. Although this had decided advantages in some aspects of the work, a great deal of useful information might have been obtained if certain strains of ticks could have been maintained. The lack of a standard sensitive reference strain has been a considerable disadvantage which could not be overcome and which has influenced the manner in which this work has been carried out. Because the tick could not be bred artificially the work could only be undertaken with unfed larvae and fully engorged adult females . Larvae are extremely small and in consequence could only be handled in batches while the fully engorged female is sluggish and contains a large quantity of semi-digested mammalian blood which invariably interfered with chemical or biochemical studies.
- Full Text:
- Date Issued: 1960
- Authors: Whitehead, G B
- Date: 1960
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5897 , http://hdl.handle.net/10962/d1013426
- Description: The work described in this dissertation was undertaken in an attempt to obtain a better understanding of the causes and relationships of insecticide resistance in Blue Tick, Boophilus decoloratus Koch, which has become an acute problem in some localities of the country. The work was undertaken at the Research Department of African Explosives and Chemical Industries Limited over a period of six years from 1953 to 1958. An attempt has been made to keep up to date with the published literature on the various aspects of these investigations up until the end of 1958. Information gained from the literature subsequent to end of 1958 has been made use of but it has not been possible for a number of reasons to follow all recent developments in the various aspects of insecticide resistance published during 1959. In the execution of this work assistance has been obtained from colleagues better equipped in the field of organic chemistry, biochemistry and statistics, than the author. Where information so gained has been used it has been duly acknowledged. Considerable assistance was rendered by laboratory assistants who were responsible for performing the considerable amount of routine collection, breeding and testing of the biological material. The blue tick is not a convenient experimental organism for studies on insecticide resistance. Even with the best facilities the tick cannot be bred satisfactorily and in consequence all supplies had to be collected from naturally-occurring populations. Although this had decided advantages in some aspects of the work, a great deal of useful information might have been obtained if certain strains of ticks could have been maintained. The lack of a standard sensitive reference strain has been a considerable disadvantage which could not be overcome and which has influenced the manner in which this work has been carried out. Because the tick could not be bred artificially the work could only be undertaken with unfed larvae and fully engorged adult females . Larvae are extremely small and in consequence could only be handled in batches while the fully engorged female is sluggish and contains a large quantity of semi-digested mammalian blood which invariably interfered with chemical or biochemical studies.
- Full Text:
- Date Issued: 1960