A new continuum mapping procedure at HartRAO
- Authors: Büchner, Sarah
- Date: 2012-06-19
- Subjects: Hartebeesthoek Radio Astronomy Observatory , Radio astronomy -- Methodology , Galactic cosmic rays
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5510 , http://hdl.handle.net/10962/d1007766 , Hartebeesthoek Radio Astronomy Observatory , Radio astronomy -- Methodology , Galactic cosmic rays
- Description: A basket weaving technique for making radio continuum maps has been developed at the Hartebeesthoek Radio Astronomy Observatory (HartRAO). This data reduction technique significantly reduces scanning effects by using independent maps scanned in orthogonal directions. The observation and data analysis procedures that were developed are presented. The technique was used to map the supernova remnant MSH 15-52 at frequencies of 5000 MHz and 8500 MHz. The flux spectral index for this supernova remnant was found to be 0.83 ± 0.02 in this frequency range. Two regions (A and B) of the Galactic plane were observed at 8500 MHz with a resolution of 6'. Region A covered the 5°x5° area 47.5°< k 52.5°, Ibl < 2.5°, and region B was the 4.2°x3° area 320.4°< I <334.6°, Ibl < 1.5°. Far infrared observations at 60 !lm were used in conjunction with the radio maps to separate the thermal and non-thermal components of the radio emission. The technique can be used to map the Galactic plane at 8500 MHz using dual polarisation once the receiver at HartRAO has been upgraded. This would fulfil a need for a medium resolution, high frequency survey of the southern Galactic plane. , Adobe Acrobat Pro 9.4.6 , Adobe Acrobat 9.46 Paper Capture Plug-in
- Full Text:
- Authors: Büchner, Sarah
- Date: 2012-06-19
- Subjects: Hartebeesthoek Radio Astronomy Observatory , Radio astronomy -- Methodology , Galactic cosmic rays
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5510 , http://hdl.handle.net/10962/d1007766 , Hartebeesthoek Radio Astronomy Observatory , Radio astronomy -- Methodology , Galactic cosmic rays
- Description: A basket weaving technique for making radio continuum maps has been developed at the Hartebeesthoek Radio Astronomy Observatory (HartRAO). This data reduction technique significantly reduces scanning effects by using independent maps scanned in orthogonal directions. The observation and data analysis procedures that were developed are presented. The technique was used to map the supernova remnant MSH 15-52 at frequencies of 5000 MHz and 8500 MHz. The flux spectral index for this supernova remnant was found to be 0.83 ± 0.02 in this frequency range. Two regions (A and B) of the Galactic plane were observed at 8500 MHz with a resolution of 6'. Region A covered the 5°x5° area 47.5°< k 52.5°, Ibl < 2.5°, and region B was the 4.2°x3° area 320.4°< I <334.6°, Ibl < 1.5°. Far infrared observations at 60 !lm were used in conjunction with the radio maps to separate the thermal and non-thermal components of the radio emission. The technique can be used to map the Galactic plane at 8500 MHz using dual polarisation once the receiver at HartRAO has been upgraded. This would fulfil a need for a medium resolution, high frequency survey of the southern Galactic plane. , Adobe Acrobat Pro 9.4.6 , Adobe Acrobat 9.46 Paper Capture Plug-in
- Full Text:
A revision of a section of the hearing and speech scale of the Griffiths Scales of Mental Development
- Authors: Kotras, Nicole
- Date: 2004
- Subjects: Griffiths scales of mental development , Psychological tests for children
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11022 , http://hdl.handle.net/10948/350 , Griffiths scales of mental development , Psychological tests for children
- Description: Since the introduction of the Griffiths Scales of Mental Development (Griffiths Scales) in the United Kingdom (1950) and South Africa (1977) they have become widely used and researched, both at a national and international level. Studies completed in South Africa have demonstrated the invaluable role the Griffiths Scales have fulfilled in the assessment of South African children of all cultural and socio-economic groups. However, research has indicated a need for the revision of the scales specifically relating to social and cultural factors that influence performance. The aim of this study was two-fold , namely: (i) to revise the 20 small pictures and the large picture of the Hearing and Speech Scale of the Griffiths Scales, making them more culturally relevant for the children of our contemporary world, and especially in South Africa; and (ii) to describe the performance of South African children, between 60 and 83 months of age, utilizing the revised pictures. For the qualitative component of the study a questionnaire pertaining to the small and large “Experimental pictures” was completed by the participants. The participants consisted of the executive committee members of the ARICD in the United Kingdom. Additionally 17 “expert “ Griffith's users and “lay-experts” working in early childhood development throughout South Africa, were included. Their responses were content analyzed and incorporated into the Experimental pictures. This resulted in the development of the Revised Griffiths pictures. The quantitative component of the study utilized two sample pools. Sample 1 (n=204) and Sample 2 (n=180) were comprised of pre-school children aged between 60 and 83 months. Sample 1 was utilized for the 20 small revised pictures and the large revised SA picture, while sample 2 was utilized for the 20 small revised pictures and the large revised United Kingdom/ European/Australian picture. Furthermore, both samples, consisted of children from all cultural, socio-economic, language, and gender groups. x The major findings of the present study were as follows: 1. Referring to sample 1, only the White and Indian pre-schoolers correctly identified a mean number of small pictures above that which was proposed by Griffiths (1960). The Coloured pre-schoolers almost identified Griffiths (1960) proposed number. 2. Referring to sample 2, all excepting the Black pre-schoolers correctly identified Griffiths’ (1960) proposed mean of small pictures. 3. All children from sample 1 and sample 2 were able to identify more stimuli from the large revised pictures, than was proposed by Griffiths (1960). 4. All four cultural groups from samples 1 and 2, elicited a mean number of descriptive words below Griffiths’ (1960) proposed criteria. 5. White pre-schoolers from sample 1 elicited a mean number of descriptive sentences above Griffiths’ (1960) proposed criteria. 6. White and Coloured pre-schoolers from sample 2 elicited a mean number of descriptive sentences above Griffiths’ (1960) proposed criteria. 7. All four cultural groups from sample 1 and sample 2, elicited a mean number of personal or possessive pronouns below Griffith's (1960) proposed criteria. 8. A general trend noted for the four cultural groups of both samples, was that the percentage of children who passed successive age-appropriate items, did not decrease stepwise as would be expected from the placement of items in order of difficulty. In view of the latter finding, it is recommended that for South African children the placement of the items for the small and large pictures of the Hearing and Speech Scale should be revised in terms of their order of difficulty. It is furthermore recommended that separate norms for South African children be established for the Hearing and Speech Scale
- Full Text:
- Authors: Kotras, Nicole
- Date: 2004
- Subjects: Griffiths scales of mental development , Psychological tests for children
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11022 , http://hdl.handle.net/10948/350 , Griffiths scales of mental development , Psychological tests for children
- Description: Since the introduction of the Griffiths Scales of Mental Development (Griffiths Scales) in the United Kingdom (1950) and South Africa (1977) they have become widely used and researched, both at a national and international level. Studies completed in South Africa have demonstrated the invaluable role the Griffiths Scales have fulfilled in the assessment of South African children of all cultural and socio-economic groups. However, research has indicated a need for the revision of the scales specifically relating to social and cultural factors that influence performance. The aim of this study was two-fold , namely: (i) to revise the 20 small pictures and the large picture of the Hearing and Speech Scale of the Griffiths Scales, making them more culturally relevant for the children of our contemporary world, and especially in South Africa; and (ii) to describe the performance of South African children, between 60 and 83 months of age, utilizing the revised pictures. For the qualitative component of the study a questionnaire pertaining to the small and large “Experimental pictures” was completed by the participants. The participants consisted of the executive committee members of the ARICD in the United Kingdom. Additionally 17 “expert “ Griffith's users and “lay-experts” working in early childhood development throughout South Africa, were included. Their responses were content analyzed and incorporated into the Experimental pictures. This resulted in the development of the Revised Griffiths pictures. The quantitative component of the study utilized two sample pools. Sample 1 (n=204) and Sample 2 (n=180) were comprised of pre-school children aged between 60 and 83 months. Sample 1 was utilized for the 20 small revised pictures and the large revised SA picture, while sample 2 was utilized for the 20 small revised pictures and the large revised United Kingdom/ European/Australian picture. Furthermore, both samples, consisted of children from all cultural, socio-economic, language, and gender groups. x The major findings of the present study were as follows: 1. Referring to sample 1, only the White and Indian pre-schoolers correctly identified a mean number of small pictures above that which was proposed by Griffiths (1960). The Coloured pre-schoolers almost identified Griffiths (1960) proposed number. 2. Referring to sample 2, all excepting the Black pre-schoolers correctly identified Griffiths’ (1960) proposed mean of small pictures. 3. All children from sample 1 and sample 2 were able to identify more stimuli from the large revised pictures, than was proposed by Griffiths (1960). 4. All four cultural groups from samples 1 and 2, elicited a mean number of descriptive words below Griffiths’ (1960) proposed criteria. 5. White pre-schoolers from sample 1 elicited a mean number of descriptive sentences above Griffiths’ (1960) proposed criteria. 6. White and Coloured pre-schoolers from sample 2 elicited a mean number of descriptive sentences above Griffiths’ (1960) proposed criteria. 7. All four cultural groups from sample 1 and sample 2, elicited a mean number of personal or possessive pronouns below Griffith's (1960) proposed criteria. 8. A general trend noted for the four cultural groups of both samples, was that the percentage of children who passed successive age-appropriate items, did not decrease stepwise as would be expected from the placement of items in order of difficulty. In view of the latter finding, it is recommended that for South African children the placement of the items for the small and large pictures of the Hearing and Speech Scale should be revised in terms of their order of difficulty. It is furthermore recommended that separate norms for South African children be established for the Hearing and Speech Scale
- Full Text:
On the life history of a cyprinid fish, Labeo cylindricus
- Weyl, Olaf L F, Booth, Anthony J
- Authors: Weyl, Olaf L F , Booth, Anthony J
- Date: 1999
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125408 , vital:35780 , https://doi.10.1023/A:1007543319416
- Description: Fishes of the genus Labeo are widely distributed throughout Africa and consist of at least 80 species which comprise 16.4% of the African cyprinid ichthyofauna (Reid 1985). Most labeo species are also commercially important throughout the African continent, having contributed significantly to various fisheries. Their roe (sensu caviar) is often harvested as an additional bycatch (Skelton et al. 1991). Despite their obvious importance, the few studies that have investigated aspects of their life history have been conducted on the larger commercial species (Lowe 1952, Mulder 1973, Balon et al. 1974, Potgieter 1974, Baird 1976, Tomasson et al. 1984, van Zyl et al. 1995).
- Full Text:
- Date Issued: 1999
- Authors: Weyl, Olaf L F , Booth, Anthony J
- Date: 1999
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125408 , vital:35780 , https://doi.10.1023/A:1007543319416
- Description: Fishes of the genus Labeo are widely distributed throughout Africa and consist of at least 80 species which comprise 16.4% of the African cyprinid ichthyofauna (Reid 1985). Most labeo species are also commercially important throughout the African continent, having contributed significantly to various fisheries. Their roe (sensu caviar) is often harvested as an additional bycatch (Skelton et al. 1991). Despite their obvious importance, the few studies that have investigated aspects of their life history have been conducted on the larger commercial species (Lowe 1952, Mulder 1973, Balon et al. 1974, Potgieter 1974, Baird 1976, Tomasson et al. 1984, van Zyl et al. 1995).
- Full Text:
- Date Issued: 1999
A new luminous cardinalfish of the genus Apogon (Perciformes:Apogonidae) from the western Pacific Ocean
- Gon, O (Ofer), 1949-, Allen, Gerald R, J.L.B. Smith Institute of Ichthyology
- Authors: Gon, O (Ofer), 1949- , Allen, Gerald R , J.L.B. Smith Institute of Ichthyology
- Date: 1998-11
- Subjects: Apogon -- Pacific Ocean -- Classification , Apogon -- Pacific Ocean -- Identification , Bioluminescence -- Pacific Ocean
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/71022 , vital:29770 , Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB)) Periodicals Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB))
- Description: Online version of original print edition of the Special Publication of the J.L.B. Smith Institute of Ichthyology; No. 62 , A new species of cardinalfish, Apogon photogaster is described based on 11 specimens from Madang Lagoon in Papua New Guinea and Galoc Island in the Philippines. This new species has 15 pectoral rays, 2 predorsal scales, 15-18 gill-rakers (8-9 developed), and 7 gill-rakers on the ceratobranchial o f the first gill-arch. It has a unique bioluminescent system, including a light organ branching forward from the second loop of the intestine and a diffuser organ along the ventrolateral part of the body.
- Full Text:
- Date Issued: 1998-11
- Authors: Gon, O (Ofer), 1949- , Allen, Gerald R , J.L.B. Smith Institute of Ichthyology
- Date: 1998-11
- Subjects: Apogon -- Pacific Ocean -- Classification , Apogon -- Pacific Ocean -- Identification , Bioluminescence -- Pacific Ocean
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/71022 , vital:29770 , Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB)) Periodicals Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB))
- Description: Online version of original print edition of the Special Publication of the J.L.B. Smith Institute of Ichthyology; No. 62 , A new species of cardinalfish, Apogon photogaster is described based on 11 specimens from Madang Lagoon in Papua New Guinea and Galoc Island in the Philippines. This new species has 15 pectoral rays, 2 predorsal scales, 15-18 gill-rakers (8-9 developed), and 7 gill-rakers on the ceratobranchial o f the first gill-arch. It has a unique bioluminescent system, including a light organ branching forward from the second loop of the intestine and a diffuser organ along the ventrolateral part of the body.
- Full Text:
- Date Issued: 1998-11
A late Cretaceous (Maastrichtian) galaxiid fish from South Africa
- Anderson, M Eric, J.L.B. Smith Institute of Ichthyology
- Authors: Anderson, M Eric , J.L.B. Smith Institute of Ichthyology
- Date: 1998-05
- Subjects: Fishes -- Indian Ocean , Flatfishes -- Indian Ocean
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/71000 , vital:29769 , Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB)) Periodicals Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB))
- Description: Online version of original print edition of the Special Publication of the J.L.B. Smith Institute of Ichthyology; No. 60 , A new teleost fish, Stompooria rogersmithi, is described from deposits of a Late Cretaceous crater lake in the Karoo, South Africa. The fossils represent the earliest known species of the recently redefined family Galaxiidae. Distinguishing features include the apposition of the dorsal and anal fins, 41- 42 vertebrae, all neural arches anterior to the dorsal fin origin fused to the centra, presence of epineurals, the opercle reduced above the level of the hyomandibular articulation, the posttemporal and supracleithrum without a connection to the seismosensory head canals, 18 principal caudal fin rays, two epurals, five hypurals, no dorsal outgrowth on the uroneural, the neural spines of the second and third preural centra similar in size, and absence of a stegural, a third uroneural, a mesocoracoid, a supramaxilla, and teeth on the maxilla and palatine bones.
- Full Text:
- Date Issued: 1998-05
- Authors: Anderson, M Eric , J.L.B. Smith Institute of Ichthyology
- Date: 1998-05
- Subjects: Fishes -- Indian Ocean , Flatfishes -- Indian Ocean
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/71000 , vital:29769 , Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB)) Periodicals Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB))
- Description: Online version of original print edition of the Special Publication of the J.L.B. Smith Institute of Ichthyology; No. 60 , A new teleost fish, Stompooria rogersmithi, is described from deposits of a Late Cretaceous crater lake in the Karoo, South Africa. The fossils represent the earliest known species of the recently redefined family Galaxiidae. Distinguishing features include the apposition of the dorsal and anal fins, 41- 42 vertebrae, all neural arches anterior to the dorsal fin origin fused to the centra, presence of epineurals, the opercle reduced above the level of the hyomandibular articulation, the posttemporal and supracleithrum without a connection to the seismosensory head canals, 18 principal caudal fin rays, two epurals, five hypurals, no dorsal outgrowth on the uroneural, the neural spines of the second and third preural centra similar in size, and absence of a stegural, a third uroneural, a mesocoracoid, a supramaxilla, and teeth on the maxilla and palatine bones.
- Full Text:
- Date Issued: 1998-05
Studies on the Zoarcidae (Teleostei: Perciformes) of the southern hemisphere, VIII: A new species of the genus Dieidolycus from Tierra del Fueg
- Anderson, M Eric, Pequeño R, Germán, J.L.B. Smith Institute of Ichthyology
- Authors: Anderson, M Eric , Pequeño R, Germán , J.L.B. Smith Institute of Ichthyology
- Date: 1998-05
- Subjects: Dieidolycus Anderson, 1988 -- Tierra del Fuego (Argentina and Chile) -- Identification , Zoarcidae -- Tierra del Fuego (Argentina and Chile)
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/70415 , vital:29653 , Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB)) Periodicals Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB))
- Description: Online version of original print edition of the Special Publication of the J.L.B. Smith Institute of Ichthyology; No. 61 , A new lower-slope eelpout of the genus Dieidolycus Anderson, 1988 (Family Zoarcidae, Subfamily Lycodinae), is described from a single juvenile female trawled in 2008-2165 m off Tierra del Fuego, Chile. It differs from congeners D. leptodermatus Anderson, 1988 and D. adocetus Anderson, 1994 by its head pore pattern, 10 caudal-fin rays, 18 pectoral-fin rays and longer gill slit.
- Full Text:
- Date Issued: 1998-05
- Authors: Anderson, M Eric , Pequeño R, Germán , J.L.B. Smith Institute of Ichthyology
- Date: 1998-05
- Subjects: Dieidolycus Anderson, 1988 -- Tierra del Fuego (Argentina and Chile) -- Identification , Zoarcidae -- Tierra del Fuego (Argentina and Chile)
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/70415 , vital:29653 , Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB)) Periodicals Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB))
- Description: Online version of original print edition of the Special Publication of the J.L.B. Smith Institute of Ichthyology; No. 61 , A new lower-slope eelpout of the genus Dieidolycus Anderson, 1988 (Family Zoarcidae, Subfamily Lycodinae), is described from a single juvenile female trawled in 2008-2165 m off Tierra del Fuego, Chile. It differs from congeners D. leptodermatus Anderson, 1988 and D. adocetus Anderson, 1994 by its head pore pattern, 10 caudal-fin rays, 18 pectoral-fin rays and longer gill slit.
- Full Text:
- Date Issued: 1998-05
"We're just teaching in a vacuum". Teaching in context in the learning for sustainability project
- Authors: Janse van Rensburg, Eureta
- Date: 1998
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/438817 , vital:73502 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137417"
- Description: Learning for Sustainability is a Danish-funded project for supporting teachers in environmental education curriculum development, in the Departments of Education in the Gauteng and Mpumalanga provinces of South Africa. The Rhodes University Environmental Education Unit is responsible for its evaluation. Instead of establishing baseline data against which to compare the project outcomes, the researchers are developing contextual profiles towards a deepening understanding of the contexts in which the teachers work, and to judge the appropriateness of project activities. This paper introduces insights from the developing profile based on questionnaires; interviews; observations during project meetings and school visits; and document analysis. The emerging issues pertain to curriculum and professional development in environmental education, within the context of educational policy transformation. In particular the paper highlights the role of context in responsive reform initiatives.
- Full Text:
- Date Issued: 1998
- Authors: Janse van Rensburg, Eureta
- Date: 1998
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/438817 , vital:73502 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137417"
- Description: Learning for Sustainability is a Danish-funded project for supporting teachers in environmental education curriculum development, in the Departments of Education in the Gauteng and Mpumalanga provinces of South Africa. The Rhodes University Environmental Education Unit is responsible for its evaluation. Instead of establishing baseline data against which to compare the project outcomes, the researchers are developing contextual profiles towards a deepening understanding of the contexts in which the teachers work, and to judge the appropriateness of project activities. This paper introduces insights from the developing profile based on questionnaires; interviews; observations during project meetings and school visits; and document analysis. The emerging issues pertain to curriculum and professional development in environmental education, within the context of educational policy transformation. In particular the paper highlights the role of context in responsive reform initiatives.
- Full Text:
- Date Issued: 1998
A case study of the implementation of the communicative approach to English second language progress testing in one secondary school in the Alexandria Circuit of the Eastern Cape Department of Education
- Authors: Ssemakalu, John
- Date: 1998
- Subjects: Communicative competence , Communicative competence in children , English language -- Study and teaching (Secondary) -- Foreign speakers -- South Africa -- Eastern Cape , Language and languages -- Study and teaching (Secondary) -- Foreign speakers -- South Africa -- Eastern Cape , Second language acquisition -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2362 , http://hdl.handle.net/10962/d1002645 , Communicative competence , Communicative competence in children , English language -- Study and teaching (Secondary) -- Foreign speakers -- South Africa -- Eastern Cape , Language and languages -- Study and teaching (Secondary) -- Foreign speakers -- South Africa -- Eastern Cape , Second language acquisition -- South Africa -- Eastern Cape
- Description: This study explores the implementation of the communicative approach (CA) to English second language progress testing in an African secondary school which falls under the Eastern Cape Department of Education. The goal of the research is to establish how teachers access, conceptualise, and apply the CA to language testing in their specific working conditions. The report of the findings of the research reveals that teachers' understanding of the CA to testing differs from that of the linguists, curriculum designers, innovators, and syllabus writers. This is caused by a combination of factors including teachers' poor working conditions, the lack of focused pre-service training and effective in-service structures for their empowennent as the agents of innovation, coupled with the poor circulation and a lack of clarity in official documents on the CA to language testing. These constraints made it impossible for teachers to implement the CA to language testing. In order to carry on with their work, however, teachers developed coping strategies by drawing, probably unconsciously, on a mixture of structuralist, sociolinguistic-psycholinguistic, communicative and any other testing practices they may have acquired during their years of service. Although based only on one school, the findings of this study indicate that for fundamental innovations such as the CA to take root, there is a need for the adoption of more dedicated, reflective implementation strategies involving proper planning and monitoring, as well as evaluation and re-evaluation of the entire process. This necessarily slow process must go hand-in-hand with a dedicated pre-service and in-service empowerment program based on consultative communication between innovator and agent; and a persuasive education/re-education approach which will encourage teachers to change their entrenched practices.
- Full Text:
- Date Issued: 1998
- Authors: Ssemakalu, John
- Date: 1998
- Subjects: Communicative competence , Communicative competence in children , English language -- Study and teaching (Secondary) -- Foreign speakers -- South Africa -- Eastern Cape , Language and languages -- Study and teaching (Secondary) -- Foreign speakers -- South Africa -- Eastern Cape , Second language acquisition -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2362 , http://hdl.handle.net/10962/d1002645 , Communicative competence , Communicative competence in children , English language -- Study and teaching (Secondary) -- Foreign speakers -- South Africa -- Eastern Cape , Language and languages -- Study and teaching (Secondary) -- Foreign speakers -- South Africa -- Eastern Cape , Second language acquisition -- South Africa -- Eastern Cape
- Description: This study explores the implementation of the communicative approach (CA) to English second language progress testing in an African secondary school which falls under the Eastern Cape Department of Education. The goal of the research is to establish how teachers access, conceptualise, and apply the CA to language testing in their specific working conditions. The report of the findings of the research reveals that teachers' understanding of the CA to testing differs from that of the linguists, curriculum designers, innovators, and syllabus writers. This is caused by a combination of factors including teachers' poor working conditions, the lack of focused pre-service training and effective in-service structures for their empowennent as the agents of innovation, coupled with the poor circulation and a lack of clarity in official documents on the CA to language testing. These constraints made it impossible for teachers to implement the CA to language testing. In order to carry on with their work, however, teachers developed coping strategies by drawing, probably unconsciously, on a mixture of structuralist, sociolinguistic-psycholinguistic, communicative and any other testing practices they may have acquired during their years of service. Although based only on one school, the findings of this study indicate that for fundamental innovations such as the CA to take root, there is a need for the adoption of more dedicated, reflective implementation strategies involving proper planning and monitoring, as well as evaluation and re-evaluation of the entire process. This necessarily slow process must go hand-in-hand with a dedicated pre-service and in-service empowerment program based on consultative communication between innovator and agent; and a persuasive education/re-education approach which will encourage teachers to change their entrenched practices.
- Full Text:
- Date Issued: 1998
A description of the language experiences of English Second-Language students entering the academic discourse communities of Rhodes University
- Authors: Reynolds, Judith Marsha
- Date: 1998
- Subjects: English language -- Study and teaching -- Foreign speakers , English language -- Ability testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2361 , http://hdl.handle.net/10962/d1002644 , English language -- Study and teaching -- Foreign speakers , English language -- Ability testing
- Description: This study is a description of the language experiences of English Second Language students in their first year at Rhodes University. It took place in the context of the changes that are currently occurring in higher education in South Africa in terms of student populations. More and more students are entering tertiary education institutions, including HWESUs, such as Rhodes University, who are considered non-traditional. These students typically have English as their second, or additional, language, and have not been adequately prepared for university study by their secondary education. This study describes the experiences of three such students in their first year at Rhodes University. Entry into a university is seen not just as acquiring knowledge, but as entering, or attempting to enter, a new culture. It is recognised that all students enter universities with other cultures or literacies already in place. In the case of non-traditional students tbese other literacies are usually at some distance from those of the university. The work of James Gee (1990) is particularly useful in understanding this process of adjusting to the demands of university study and the effect that previous experiences have on this process. This study is an attempt to discover and describe the literacies that these three students brought with them to university and the effect these literacies had on their attempts to enter academic discourse communities of the university. An ethnographic research method was adopted in order to do this. The study is also an attempt to evaluate, from the perspective of the three students, the appropriacy of the various changes that Rhodes University has made since the numbers of non-traditional students has started to increase.
- Full Text:
- Date Issued: 1998
- Authors: Reynolds, Judith Marsha
- Date: 1998
- Subjects: English language -- Study and teaching -- Foreign speakers , English language -- Ability testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2361 , http://hdl.handle.net/10962/d1002644 , English language -- Study and teaching -- Foreign speakers , English language -- Ability testing
- Description: This study is a description of the language experiences of English Second Language students in their first year at Rhodes University. It took place in the context of the changes that are currently occurring in higher education in South Africa in terms of student populations. More and more students are entering tertiary education institutions, including HWESUs, such as Rhodes University, who are considered non-traditional. These students typically have English as their second, or additional, language, and have not been adequately prepared for university study by their secondary education. This study describes the experiences of three such students in their first year at Rhodes University. Entry into a university is seen not just as acquiring knowledge, but as entering, or attempting to enter, a new culture. It is recognised that all students enter universities with other cultures or literacies already in place. In the case of non-traditional students tbese other literacies are usually at some distance from those of the university. The work of James Gee (1990) is particularly useful in understanding this process of adjusting to the demands of university study and the effect that previous experiences have on this process. This study is an attempt to discover and describe the literacies that these three students brought with them to university and the effect these literacies had on their attempts to enter academic discourse communities of the university. An ethnographic research method was adopted in order to do this. The study is also an attempt to evaluate, from the perspective of the three students, the appropriacy of the various changes that Rhodes University has made since the numbers of non-traditional students has started to increase.
- Full Text:
- Date Issued: 1998
A framework for interpreting noisy, two-dimensional images, based on a fuzzification of programmed, attributed graph grammars
- Authors: Watkins, Gregory Shroll
- Date: 1998
- Subjects: Music -- Data processing Computer sound processing Artificial intelligence -- Musical applications Fuzzy systems
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4604 , http://hdl.handle.net/10962/d1004862
- Description: This thesis investigates a fuzzy syntactic approach to the interpretation of noisy two-dimensional images. This approach is based on a modification of the attributed graph grammar formalism to utilise fuzzy membership functions in the applicability predicates. As far as we are aware, this represents the first such modification of graph grammars. Furthermore, we develop a method for programming the resultant fuzzy attributed graph grammars through the use of non-deterministic control diagrams. To do this, we modify the standard programming mechanism to allow it to cope with the fuzzy certainty values associated with productions in our grammar. Our objective was to develop a flexible framework which can be used for the recognition of a wide variety of image classes, and which is adept at dealing with noise in these images. Programmed graph grammars are specifically chosen for the ease with which they allow one to specify a new two-dimensional image class. We implement a prototype system for Optical Music Recognition using our framework. This system allows us to test the capabilities of the framework for coping with noise in the context of handwritten music score recognition. Preliminary results from the prototype system show that the framework copes well with noisy images.
- Full Text:
- Date Issued: 1998
- Authors: Watkins, Gregory Shroll
- Date: 1998
- Subjects: Music -- Data processing Computer sound processing Artificial intelligence -- Musical applications Fuzzy systems
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4604 , http://hdl.handle.net/10962/d1004862
- Description: This thesis investigates a fuzzy syntactic approach to the interpretation of noisy two-dimensional images. This approach is based on a modification of the attributed graph grammar formalism to utilise fuzzy membership functions in the applicability predicates. As far as we are aware, this represents the first such modification of graph grammars. Furthermore, we develop a method for programming the resultant fuzzy attributed graph grammars through the use of non-deterministic control diagrams. To do this, we modify the standard programming mechanism to allow it to cope with the fuzzy certainty values associated with productions in our grammar. Our objective was to develop a flexible framework which can be used for the recognition of a wide variety of image classes, and which is adept at dealing with noise in these images. Programmed graph grammars are specifically chosen for the ease with which they allow one to specify a new two-dimensional image class. We implement a prototype system for Optical Music Recognition using our framework. This system allows us to test the capabilities of the framework for coping with noise in the context of handwritten music score recognition. Preliminary results from the prototype system show that the framework copes well with noisy images.
- Full Text:
- Date Issued: 1998
A molecular genetic assessment of the population structure and variation in two inshore dolphin genera on the east coast of South Africa
- Smith-Goodwin, Jacqueline Anne
- Authors: Smith-Goodwin, Jacqueline Anne
- Date: 1998
- Subjects: Dolphins -- South Africa Variation (Biology) Dolphins -- Genetics Population genetics Bottlenose dolphin -- South Africa Sousa -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4007 , http://hdl.handle.net/10962/d1004067
- Description: Coastal dolphins on the South African east coast are threatened by degradation and loss of habitat as a result of increasing coastal development, industrial effluent and agricultural runoff. In addition, dolphins off the coast of KwaZulu-Natal have, for more than four decades, been heavily exploited through unchecked incidental capture in shark nets set at 45 beaches. In light of the high rate of mortality and apparent depletion of both species, the persistence of bottlenose (Tursiops truncatus) and humpback (Sousa chinensis) dolphins in that region has been questioned. Genetic variation in south east African dolphin populations was determined as a means of assessing the fitness of the populations and their resilience to demographic disturbances. Furthermore, in order to determine the effects of continued mortality on the KwaZulu-Natal subpopulations, it was necessary to determine whether they are open or closed to immigration from the adjacent East Cape region, which represents a relatively unstressed region, characterised by a lack of shark nets and less intensive coastal activities. Genetic variation and differentiation in the maternal genome was assessed by determining the sequence of the first 400 bases of the mtDNA control region in bottlenose and humpback dolphins from KwaZulu-Natal and the East Cape. Nuclear variation and differentiation was estimated at six microsatellite loci and compared with earlier estimates determined from allozyme electrophoresis. Random amplified polymorphic DNA (RAPD) was assessed as a means of identifying population subdivisions and diagnostic population markers. Both bottlenose and humpback dolphins on the South African east coast are characterised by low nuclear and organellar genetic variation, consistent with a possible genetic bottleneck, the inferred date of which coincides with the onset of the last glacial period. Genetic variation in South African bottlenose dolphins was lower than that reported elsewhere for the species, while an intraspecific comparison supported lower genetic variation in South African humpback dolphins than in humpback dolphins sampled off Hong Kong. An analysis of molecular variance (AMOVA), performed on mtDNA haplotype frequency data indicated, for both species, significant genetic subdivision, concordant with geographic location. The data suggested female bottlenose dolphins demonstrate regional philopatry, displaying limited movement between KwaZulu-Natal and the East Cape. Female humpback dolphins tend towards strict local philopatry, with significant maternal differentiation evident both within and between regional subdivisions. Differentiation in microsatellite allele frequencies was also demonstrated between KwaZulu-Natal and the East Cape for both species, suggesting that the movement of male bottlenose and humpback dolphins may also be restricted. Nonetheless, considerably higher nuclear gene flow estimates suggested that males of both species represent the principal vectors of gene dispersal. The implications of historically low genetic variability and population subdivision in South African dolphins are important in view of the current rate of mortality in KwaZulu-Natal. The persistence of coastal dolphin populations relies on their ability to recover following a bottleneck event. Continued removal of demographically important age-sex classes such as occurs in shark nets, may not only further reduce the genetic variation, but would ultimately deplete dolphin populations in KwaZulu-Natal beyond a sustainable number, resulting in eventual local extinction. The differentiation of the two regions implies that, in the event of local extinction occurring, dolphins, particularly females, from adjacent regions will not readily re-colonise the area. This would result in fragmentation of the south east African populations and ensure reproductive isolation from neighbouring populations on the east African coast.
- Full Text:
- Date Issued: 1998
- Authors: Smith-Goodwin, Jacqueline Anne
- Date: 1998
- Subjects: Dolphins -- South Africa Variation (Biology) Dolphins -- Genetics Population genetics Bottlenose dolphin -- South Africa Sousa -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4007 , http://hdl.handle.net/10962/d1004067
- Description: Coastal dolphins on the South African east coast are threatened by degradation and loss of habitat as a result of increasing coastal development, industrial effluent and agricultural runoff. In addition, dolphins off the coast of KwaZulu-Natal have, for more than four decades, been heavily exploited through unchecked incidental capture in shark nets set at 45 beaches. In light of the high rate of mortality and apparent depletion of both species, the persistence of bottlenose (Tursiops truncatus) and humpback (Sousa chinensis) dolphins in that region has been questioned. Genetic variation in south east African dolphin populations was determined as a means of assessing the fitness of the populations and their resilience to demographic disturbances. Furthermore, in order to determine the effects of continued mortality on the KwaZulu-Natal subpopulations, it was necessary to determine whether they are open or closed to immigration from the adjacent East Cape region, which represents a relatively unstressed region, characterised by a lack of shark nets and less intensive coastal activities. Genetic variation and differentiation in the maternal genome was assessed by determining the sequence of the first 400 bases of the mtDNA control region in bottlenose and humpback dolphins from KwaZulu-Natal and the East Cape. Nuclear variation and differentiation was estimated at six microsatellite loci and compared with earlier estimates determined from allozyme electrophoresis. Random amplified polymorphic DNA (RAPD) was assessed as a means of identifying population subdivisions and diagnostic population markers. Both bottlenose and humpback dolphins on the South African east coast are characterised by low nuclear and organellar genetic variation, consistent with a possible genetic bottleneck, the inferred date of which coincides with the onset of the last glacial period. Genetic variation in South African bottlenose dolphins was lower than that reported elsewhere for the species, while an intraspecific comparison supported lower genetic variation in South African humpback dolphins than in humpback dolphins sampled off Hong Kong. An analysis of molecular variance (AMOVA), performed on mtDNA haplotype frequency data indicated, for both species, significant genetic subdivision, concordant with geographic location. The data suggested female bottlenose dolphins demonstrate regional philopatry, displaying limited movement between KwaZulu-Natal and the East Cape. Female humpback dolphins tend towards strict local philopatry, with significant maternal differentiation evident both within and between regional subdivisions. Differentiation in microsatellite allele frequencies was also demonstrated between KwaZulu-Natal and the East Cape for both species, suggesting that the movement of male bottlenose and humpback dolphins may also be restricted. Nonetheless, considerably higher nuclear gene flow estimates suggested that males of both species represent the principal vectors of gene dispersal. The implications of historically low genetic variability and population subdivision in South African dolphins are important in view of the current rate of mortality in KwaZulu-Natal. The persistence of coastal dolphin populations relies on their ability to recover following a bottleneck event. Continued removal of demographically important age-sex classes such as occurs in shark nets, may not only further reduce the genetic variation, but would ultimately deplete dolphin populations in KwaZulu-Natal beyond a sustainable number, resulting in eventual local extinction. The differentiation of the two regions implies that, in the event of local extinction occurring, dolphins, particularly females, from adjacent regions will not readily re-colonise the area. This would result in fragmentation of the south east African populations and ensure reproductive isolation from neighbouring populations on the east African coast.
- Full Text:
- Date Issued: 1998
A nutritional evaluation of effluent grown algae and zooplakton as feed ingredients for Xiphohorous helleri, Poecilia reticulata and Poecilia velifera (Pisces : Poeciliidae)
- Authors: Potts, Warren M
- Date: 1998
- Subjects: Poeciliidae , Poeciliidae -- Nutrition , Zooplankton , Algae , Poeciliidae -- Feeding and feeds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5306 , http://hdl.handle.net/10962/d1005151 , Poeciliidae , Poeciliidae -- Nutrition , Zooplankton , Algae , Poeciliidae -- Feeding and feeds
- Description: The aim of this study was to evaluate the nutritional value of algae and zooplankton grown in an algal integrated ponding system for poeciliids. The available information on the nutritional requirements of poeciliids was compared with a proximate analysis of the algae and zooplankton. The effluent grown algae and zooplankton had a crude protein value of 41.47 ± 0.2% and 36.84 ± 0.3%, a lipid content of 4.8 ±. 0.4% and 11.1 ± 0.8% and a carbohydrate content of 35.13 ± 0.8% and 31.06 ± 0.6% respectively. These values compared favourably with those of the known nutritional requirements of poeciliids. To test if the nutritional value of the algae and zooplankton in the AlPS was constant, the species composition of the algae and the crude protein content of the algae and zooplankton in the high rate oxidation ponds were measured monthly and bi-weekly for a year respectively. The species composition remained fairly stable for the duration of the experiment and the average protein composition of the algae and zooplankton was 43.4 ± 4.4% and 38.6 ±2.8% respectively. This indicated that the algae and zooplankton in the AlPS provided high protein biomass through the year. The quality of the effluent grown algal and zooplankton biomass was evaluated by analysing their amino acid composition and comparing it with the amino acid composition of the body tissue of X. helleri. With respect to the amino acid composition of the body tissue of X. helleri, the amino acid profile of the algae had a 69% and the zooplankton a 63% similarity. The quality of the pure algal and zooplankton protein was also tested biologically, by feeding them directly to poeciliids during a ten week growth trial. The algae and zooplankton diets did not result in adequate growth compared to poeciliids which were fed a formulated control diet. The initial growth trial also evaluated the effect of processing on the chemical composition of the algae and its biological effect on fish fed with it. There were no significant differences in the chemical composition of fresh and sun dried algae and this was reflected in the growth rates of the fish which did not differ significantly. Freeze dried algae had a lower crude protein content than fresh and sun dried algae and a poorer amino acid composition. Fish fed freeze dried algae exhibited poorer growth and survival in comparison to the other treatments. The gut transit times of X. helleri and the gastric evacuation times of poeciliids were determined using colour dyes incorporated in the diet and by sacrificing fish at predetermined intervals after feeding respectively. The gut transit time of X. helleri fed a sun dried algal diet and a formulated diet was 225 ± 8.55 minutes and 261.93 ± 10.86 minutes respectively. The gastric evacuation times of X. helleri, P. reticu/ata and P. velifera were 7, 9 and 8 hours respectively. Since the maximum amount of food in the hindgut after feeding was detemined to be 3, 5 and 3 hours in X. helleri, P. reticulata and P. velifera respectively, fish were sacrificed at these times in the digestibility study. The digestibility of sun dried algae was determined using 1 % chromic oxide as an internal marker in the algae. The apparent crude protein digestibility of sun dried effluent grown algae ranged from 65%-75% in the three poeciliid species. Based on the results of the chemical and biological analysis of the algae and zooplankton, conventional diets incorporating algae at 5% and 20% protein inclusion levels were formulated. These diets and a treatment in which zooplankton, reared in the AlPS were fed as a dietary supplement to a formulated diet were fed to poeciliids for twelve weeks. No significant differences in the growth of poeciliids fed any of the test diets were observed. It was concluded that the algae could be incorporated into poeciliid formulated diets up to level of 20% protein inclusion without any negative effect on the growth of the fish. The chemical and biological evaluation of the algae suggested that it had a similar nutritional quality to soyabean meal. Poeciliid growth was not enhanced with a zooplankton supplement, however a possible low feeding rate by poeciliids on the zooplankton as a result of their small size may have affected the result. The colour enhancement potential of effluent grown algae and zooplankton was evaluated biologically in ten and twelve week growth trials using visual observation (31 people) and by using a chromameter. While pure, sun dried algae significantly enhanced the colour of P. reticulata, no significant differences in the colour of poeciliids were observed or recorded when fish were fed diets incorporating sun dried algae up to levels of 20% protein inclusion. The effect of effluent grown algae and zooplankton on poeciliid health was also tested biologically in the ten and twelve week growth trials. The high mortalities (75%-84%) recorded for X. hel/eri when fed the pure algal and zooplankton diets were considered to be as a result of the nutritional inadequacy of the diets since there were significantly less mortalities in fish fed the formulated control diet and 63% of the fish that died during the course of the trial were emaciated. In addition, fewer mortalities (10%-40%) were recorded in X. hel/eri fed the nutritionally adequate formulated diets in the twelve week growth trial. No symptoms of disease were recorded in the twelve week growth trial and the algae was considered to have no toxicological or pathological effects on poeciliids. Centrifugation, sand filtration, sedimentation, microstraining and biological harvest were evaluated as methods of small scale algal harvest from the high rate oxidation ponds. Algae could be harvested most efficiently with little associated labour by sedimentation (without flocculating agents) and by microstraining with 60IJm mesh. Effluent grown algae can replace conventional feed ingredients up to a level of 20% protein inclusion without negatively effecting the growth, colour, health or survival of poeciliids.
- Full Text:
- Date Issued: 1998
- Authors: Potts, Warren M
- Date: 1998
- Subjects: Poeciliidae , Poeciliidae -- Nutrition , Zooplankton , Algae , Poeciliidae -- Feeding and feeds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5306 , http://hdl.handle.net/10962/d1005151 , Poeciliidae , Poeciliidae -- Nutrition , Zooplankton , Algae , Poeciliidae -- Feeding and feeds
- Description: The aim of this study was to evaluate the nutritional value of algae and zooplankton grown in an algal integrated ponding system for poeciliids. The available information on the nutritional requirements of poeciliids was compared with a proximate analysis of the algae and zooplankton. The effluent grown algae and zooplankton had a crude protein value of 41.47 ± 0.2% and 36.84 ± 0.3%, a lipid content of 4.8 ±. 0.4% and 11.1 ± 0.8% and a carbohydrate content of 35.13 ± 0.8% and 31.06 ± 0.6% respectively. These values compared favourably with those of the known nutritional requirements of poeciliids. To test if the nutritional value of the algae and zooplankton in the AlPS was constant, the species composition of the algae and the crude protein content of the algae and zooplankton in the high rate oxidation ponds were measured monthly and bi-weekly for a year respectively. The species composition remained fairly stable for the duration of the experiment and the average protein composition of the algae and zooplankton was 43.4 ± 4.4% and 38.6 ±2.8% respectively. This indicated that the algae and zooplankton in the AlPS provided high protein biomass through the year. The quality of the effluent grown algal and zooplankton biomass was evaluated by analysing their amino acid composition and comparing it with the amino acid composition of the body tissue of X. helleri. With respect to the amino acid composition of the body tissue of X. helleri, the amino acid profile of the algae had a 69% and the zooplankton a 63% similarity. The quality of the pure algal and zooplankton protein was also tested biologically, by feeding them directly to poeciliids during a ten week growth trial. The algae and zooplankton diets did not result in adequate growth compared to poeciliids which were fed a formulated control diet. The initial growth trial also evaluated the effect of processing on the chemical composition of the algae and its biological effect on fish fed with it. There were no significant differences in the chemical composition of fresh and sun dried algae and this was reflected in the growth rates of the fish which did not differ significantly. Freeze dried algae had a lower crude protein content than fresh and sun dried algae and a poorer amino acid composition. Fish fed freeze dried algae exhibited poorer growth and survival in comparison to the other treatments. The gut transit times of X. helleri and the gastric evacuation times of poeciliids were determined using colour dyes incorporated in the diet and by sacrificing fish at predetermined intervals after feeding respectively. The gut transit time of X. helleri fed a sun dried algal diet and a formulated diet was 225 ± 8.55 minutes and 261.93 ± 10.86 minutes respectively. The gastric evacuation times of X. helleri, P. reticu/ata and P. velifera were 7, 9 and 8 hours respectively. Since the maximum amount of food in the hindgut after feeding was detemined to be 3, 5 and 3 hours in X. helleri, P. reticulata and P. velifera respectively, fish were sacrificed at these times in the digestibility study. The digestibility of sun dried algae was determined using 1 % chromic oxide as an internal marker in the algae. The apparent crude protein digestibility of sun dried effluent grown algae ranged from 65%-75% in the three poeciliid species. Based on the results of the chemical and biological analysis of the algae and zooplankton, conventional diets incorporating algae at 5% and 20% protein inclusion levels were formulated. These diets and a treatment in which zooplankton, reared in the AlPS were fed as a dietary supplement to a formulated diet were fed to poeciliids for twelve weeks. No significant differences in the growth of poeciliids fed any of the test diets were observed. It was concluded that the algae could be incorporated into poeciliid formulated diets up to level of 20% protein inclusion without any negative effect on the growth of the fish. The chemical and biological evaluation of the algae suggested that it had a similar nutritional quality to soyabean meal. Poeciliid growth was not enhanced with a zooplankton supplement, however a possible low feeding rate by poeciliids on the zooplankton as a result of their small size may have affected the result. The colour enhancement potential of effluent grown algae and zooplankton was evaluated biologically in ten and twelve week growth trials using visual observation (31 people) and by using a chromameter. While pure, sun dried algae significantly enhanced the colour of P. reticulata, no significant differences in the colour of poeciliids were observed or recorded when fish were fed diets incorporating sun dried algae up to levels of 20% protein inclusion. The effect of effluent grown algae and zooplankton on poeciliid health was also tested biologically in the ten and twelve week growth trials. The high mortalities (75%-84%) recorded for X. hel/eri when fed the pure algal and zooplankton diets were considered to be as a result of the nutritional inadequacy of the diets since there were significantly less mortalities in fish fed the formulated control diet and 63% of the fish that died during the course of the trial were emaciated. In addition, fewer mortalities (10%-40%) were recorded in X. hel/eri fed the nutritionally adequate formulated diets in the twelve week growth trial. No symptoms of disease were recorded in the twelve week growth trial and the algae was considered to have no toxicological or pathological effects on poeciliids. Centrifugation, sand filtration, sedimentation, microstraining and biological harvest were evaluated as methods of small scale algal harvest from the high rate oxidation ponds. Algae could be harvested most efficiently with little associated labour by sedimentation (without flocculating agents) and by microstraining with 60IJm mesh. Effluent grown algae can replace conventional feed ingredients up to a level of 20% protein inclusion without negatively effecting the growth, colour, health or survival of poeciliids.
- Full Text:
- Date Issued: 1998
A profile of young sex offenders in South Africa : a pilot study
- Authors: Wood, Catherine Jane
- Date: 1998
- Subjects: Sex offenders -- Psychology , Paraphilias , Sex offenders -- South Africa -- Psychology , Teenage sex offenders -- South Africa -- Psychology , Teenage sex offenders
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3089 , http://hdl.handle.net/10962/d1002598 , Sex offenders -- Psychology , Paraphilias , Sex offenders -- South Africa -- Psychology , Teenage sex offenders -- South Africa -- Psychology , Teenage sex offenders
- Description: In-depth interviews and psychometric tests were conducted with 20 young, South African male, hands-on sex offenders, between the ages of seven and 15 years. These offenders were referred by both the legal system and the welfare and health system. The data was gathered for the purpose of drawing up a descriptive profile of salient psychological and sociological characteristics of this population group, the patterns of offenses, the circumstances under which the offenses occurred and victims selected. Results showed that half the sample had committed prior sex offenses. The majority of young sex offenders had a history of consenting sexual interactions, had committed a non-sexual offense and engaged in a range of other antisocial behaviours. Half the sample reported a history of physical or sexual abuse (under-reporting of such victimization experiences was suspected). Typically, the young sex offender w:~s sexually naive and had not received any suitable sex education. He was usually a scholar although his school attendance was often infrequent and he was likely to have failed one or more standards. His intelligence quotient was most likely to fall in or below the borderline range of functioning. He tended to be either socially isolated and socially anxious or alternatively reported having a number of friends and appeared to have adequate social skills. His home environment was typically characterized by overcrowding, alcohol abuse and domestic violence. A significant male relative of his was likely to have committed a criminal offense. In his community environment, he regularly witnessed violence and sexual activity. The sex offenses were usually carried out with a co-perpetrator in a variety of venues. The victim was usually known and younger (mean age = seven years) than the perpetrator (mean age = 12 years). The overall results suggest that young sex offenders commit an array of sexual offenses that do not represent sexual experimentation, but rather indicate a developing pattern of sexual deviance. Comparisons between the above profile and the literature findings are explored. Finally, recommendations for structural changes, assessment procedures, additional future research pessibilities and guidelines for the development of appropriate - treatment programmes are outlined.
- Full Text:
- Date Issued: 1998
- Authors: Wood, Catherine Jane
- Date: 1998
- Subjects: Sex offenders -- Psychology , Paraphilias , Sex offenders -- South Africa -- Psychology , Teenage sex offenders -- South Africa -- Psychology , Teenage sex offenders
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3089 , http://hdl.handle.net/10962/d1002598 , Sex offenders -- Psychology , Paraphilias , Sex offenders -- South Africa -- Psychology , Teenage sex offenders -- South Africa -- Psychology , Teenage sex offenders
- Description: In-depth interviews and psychometric tests were conducted with 20 young, South African male, hands-on sex offenders, between the ages of seven and 15 years. These offenders were referred by both the legal system and the welfare and health system. The data was gathered for the purpose of drawing up a descriptive profile of salient psychological and sociological characteristics of this population group, the patterns of offenses, the circumstances under which the offenses occurred and victims selected. Results showed that half the sample had committed prior sex offenses. The majority of young sex offenders had a history of consenting sexual interactions, had committed a non-sexual offense and engaged in a range of other antisocial behaviours. Half the sample reported a history of physical or sexual abuse (under-reporting of such victimization experiences was suspected). Typically, the young sex offender w:~s sexually naive and had not received any suitable sex education. He was usually a scholar although his school attendance was often infrequent and he was likely to have failed one or more standards. His intelligence quotient was most likely to fall in or below the borderline range of functioning. He tended to be either socially isolated and socially anxious or alternatively reported having a number of friends and appeared to have adequate social skills. His home environment was typically characterized by overcrowding, alcohol abuse and domestic violence. A significant male relative of his was likely to have committed a criminal offense. In his community environment, he regularly witnessed violence and sexual activity. The sex offenses were usually carried out with a co-perpetrator in a variety of venues. The victim was usually known and younger (mean age = seven years) than the perpetrator (mean age = 12 years). The overall results suggest that young sex offenders commit an array of sexual offenses that do not represent sexual experimentation, but rather indicate a developing pattern of sexual deviance. Comparisons between the above profile and the literature findings are explored. Finally, recommendations for structural changes, assessment procedures, additional future research pessibilities and guidelines for the development of appropriate - treatment programmes are outlined.
- Full Text:
- Date Issued: 1998
A qualitative investigation of schizophrenic dreams
- Authors: Kumarapaapillai, Niranjula
- Date: 1998
- Subjects: Schizophrenia , Dreams -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3005 , http://hdl.handle.net/10962/d1002514 , Schizophrenia , Dreams -- Psychological aspects
- Description: This project attempts to articulate an understanding of the worlds of selected subjects suffering from schizophrenia, through their dreams. It proceeds from the implicit question of whether or not schizophrenic dreams reflect the schizophrenic worlds as literature defines, and tries to address some of the dream features which reflect the schizophrenic world. Five psychiatric inpatients suffering from schizophrenia were selected. The data gathered included the subjects' dreams and subsequent interviews for the purpose of clarification of the dreams. A phenomenological-hermeneutic methodology was deemed to be appropriate as it gave access to the richness of the dream experiences as well as the following dialogue between the data and literature. The results indicate that the subjects' dream worlds bear evidence to a fragmented state of ego which is to be expected to be found in schizophrenia. On the other hand some of these subjects' dreams also point to evolving health that is present in their world, at least on an intrapsychic level.
- Full Text:
- Date Issued: 1998
- Authors: Kumarapaapillai, Niranjula
- Date: 1998
- Subjects: Schizophrenia , Dreams -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3005 , http://hdl.handle.net/10962/d1002514 , Schizophrenia , Dreams -- Psychological aspects
- Description: This project attempts to articulate an understanding of the worlds of selected subjects suffering from schizophrenia, through their dreams. It proceeds from the implicit question of whether or not schizophrenic dreams reflect the schizophrenic worlds as literature defines, and tries to address some of the dream features which reflect the schizophrenic world. Five psychiatric inpatients suffering from schizophrenia were selected. The data gathered included the subjects' dreams and subsequent interviews for the purpose of clarification of the dreams. A phenomenological-hermeneutic methodology was deemed to be appropriate as it gave access to the richness of the dream experiences as well as the following dialogue between the data and literature. The results indicate that the subjects' dream worlds bear evidence to a fragmented state of ego which is to be expected to be found in schizophrenia. On the other hand some of these subjects' dreams also point to evolving health that is present in their world, at least on an intrapsychic level.
- Full Text:
- Date Issued: 1998
A rock in the seething chasm : Thomas Keating's understanding of the human person and of spirituality as a basis for contemporary pastoral counselling
- Authors: Burton, Rodney Lawrence
- Date: 1998
- Subjects: Pastoral counselling Psychology and religion Psychology and religion Spirituality -- Christianity Spiritual life -- Christianity Keating, Thomas -- Criticism and interpretation
- Language: English
- Type: Thesis , Masters , MTh
- Identifier: vital:1246 , http://hdl.handle.net/10962/d1009960
- Description: Contemporary pastoral counselling has many unresolved problems associated with its practice, causing frustration for both counsellors and counsellees. This thesis suggests that such problems are related to the fact that pastoral counselling is overshadowed by the dominant schools of psychology, to the detriment of its spirituality. Furthermore, by attending to both its "values" and its "aims", contemporary pastoral counselling is shown to lack a distinctive theoretical base. This thesis proposes that pastoral counselling is, in fact, the reparative dimension of spiritual direction. Referring to such counselling as " therapeutic spiritual direction" best expresses this concept. Some of the ways in which this redefinition of pastoral counselling may alleviate problems which are currently experienced, particularly by counsellors, are highlighted. A spirituality appropriate to this discipline is outlined. Both Keating's life in general, and eight anthropological models used in conjunction with his teaching on Centering Prayer, are examined to provide a theological foundation for therapeutic spiritual direction. Utilising a conflation of Keating's models, supplemented by insights from his spirituality, individuals are located within an evolutionary-developmental context, within which the reality of sin is acknowledged. Attention is given, in a holistic fashion, to the physical, emotional, and spiritual faculties, and to relationships with both the world at large, and God in particular. Real and potential problems in emotional and spiritual formation are explained with reference to four "energy centres". Therapeutic spiritual direction is characterised by the environment within which it is conducted, and SLX identifiable stages through which it passes. Based on Keating's models, an Instrument is developed to facilitate such counselling, particularly in its diagnostic phases. Use of the means of grace and traditionally Christian disciplines and forms of ministry are emphasised for healing, and a spectrum of suggested treatment modalities is generated. The place of other health-care disciplines and social-care agencies is recognised, and discriminating co-operation and dialogue with them and with other faith traditions is encouraged This thesis has profound significance for the way in which pastoral counselling should be practised. In the light of these insights, some implications for the training of counsellors and for ministry in South Africa are noted.
- Full Text:
- Date Issued: 1998
- Authors: Burton, Rodney Lawrence
- Date: 1998
- Subjects: Pastoral counselling Psychology and religion Psychology and religion Spirituality -- Christianity Spiritual life -- Christianity Keating, Thomas -- Criticism and interpretation
- Language: English
- Type: Thesis , Masters , MTh
- Identifier: vital:1246 , http://hdl.handle.net/10962/d1009960
- Description: Contemporary pastoral counselling has many unresolved problems associated with its practice, causing frustration for both counsellors and counsellees. This thesis suggests that such problems are related to the fact that pastoral counselling is overshadowed by the dominant schools of psychology, to the detriment of its spirituality. Furthermore, by attending to both its "values" and its "aims", contemporary pastoral counselling is shown to lack a distinctive theoretical base. This thesis proposes that pastoral counselling is, in fact, the reparative dimension of spiritual direction. Referring to such counselling as " therapeutic spiritual direction" best expresses this concept. Some of the ways in which this redefinition of pastoral counselling may alleviate problems which are currently experienced, particularly by counsellors, are highlighted. A spirituality appropriate to this discipline is outlined. Both Keating's life in general, and eight anthropological models used in conjunction with his teaching on Centering Prayer, are examined to provide a theological foundation for therapeutic spiritual direction. Utilising a conflation of Keating's models, supplemented by insights from his spirituality, individuals are located within an evolutionary-developmental context, within which the reality of sin is acknowledged. Attention is given, in a holistic fashion, to the physical, emotional, and spiritual faculties, and to relationships with both the world at large, and God in particular. Real and potential problems in emotional and spiritual formation are explained with reference to four "energy centres". Therapeutic spiritual direction is characterised by the environment within which it is conducted, and SLX identifiable stages through which it passes. Based on Keating's models, an Instrument is developed to facilitate such counselling, particularly in its diagnostic phases. Use of the means of grace and traditionally Christian disciplines and forms of ministry are emphasised for healing, and a spectrum of suggested treatment modalities is generated. The place of other health-care disciplines and social-care agencies is recognised, and discriminating co-operation and dialogue with them and with other faith traditions is encouraged This thesis has profound significance for the way in which pastoral counselling should be practised. In the light of these insights, some implications for the training of counsellors and for ministry in South Africa are noted.
- Full Text:
- Date Issued: 1998
A social history of white working class women in industrializing Port Elizabeth, 1917-1936
- Authors: Gibbs, Patricia Anne
- Date: 1998
- Subjects: Women -- South Africa -- Port Elizabeth -- History , Women -- Employment -- South Africa -- Port Elizabeth -- History , Port Elizabeth (South Africa) -- History
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2543 , http://hdl.handle.net/10962/d1002395 , Women -- South Africa -- Port Elizabeth -- History , Women -- Employment -- South Africa -- Port Elizabeth -- History , Port Elizabeth (South Africa) -- History
- Description: The study period saw a significant increase in the urbanisation of whites and blacks in Port Elizabeth induced by droughts and coercive legislation, but also by burgeoning industrialisation. Industry had been given great stimulus by World War 1 and maintained by protectionist legislation in the 1920s which the local state and industrialists came to endorse. The ethos of the town was overwhelmingly British in terms of the population, the composition of the local council, business interests and the prevailing culture. Whites formed the largest component of the population in Port Elizabeth during the inter-war years. The majority of white women lived in the North End, the industrial hub and a major working class area of the city. Although the provision of housing was initially neglected, economic and subeconomic housing in the 1930s helped to create both racial separation and a sense of community between sectors of the working class. Yet, white working class women did not form a homogenous group, but rather consisted of different ethnic groups, occupations and classes. The Afrikaans speaking sector, formed a significant component of the industrial labour force especially in the leather, food and beverage and clothing industries. In a centre where white labour was favoured and marketed as an advantage to outside investors, they rapidly displaced coloured women. The female workforce was basically young, underpaid (especially in comparison to wages on the Rand) and temporary. While white women were still in evidence in other occupations such as domestic work and in the informal sector, their numbers here steadily diminished as both racial segregation and municipal regulation, were implemented. Against a background of chaotic social conditions, large slum areas and the spread of infectious diseases, the local council did much to improve health services particularly for women and children. Poor relief instituted in 1919 was, however, less forthcoming and female - headed households were often left to rely on the services of local welfare organisations. The extended family, however, was the norm affording support against atomization. Although pressurised by social ills throughout the period, the family was increasingly buttressed by state assistance. Prevailing morality was likewise actively constructed in terms of legislative repression and racial division. This often lead to social aberrations such as infanticide which was only reduced by the increase of state assistance and, in the longer term, social mobility of the whites.
- Full Text:
- Date Issued: 1998
- Authors: Gibbs, Patricia Anne
- Date: 1998
- Subjects: Women -- South Africa -- Port Elizabeth -- History , Women -- Employment -- South Africa -- Port Elizabeth -- History , Port Elizabeth (South Africa) -- History
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2543 , http://hdl.handle.net/10962/d1002395 , Women -- South Africa -- Port Elizabeth -- History , Women -- Employment -- South Africa -- Port Elizabeth -- History , Port Elizabeth (South Africa) -- History
- Description: The study period saw a significant increase in the urbanisation of whites and blacks in Port Elizabeth induced by droughts and coercive legislation, but also by burgeoning industrialisation. Industry had been given great stimulus by World War 1 and maintained by protectionist legislation in the 1920s which the local state and industrialists came to endorse. The ethos of the town was overwhelmingly British in terms of the population, the composition of the local council, business interests and the prevailing culture. Whites formed the largest component of the population in Port Elizabeth during the inter-war years. The majority of white women lived in the North End, the industrial hub and a major working class area of the city. Although the provision of housing was initially neglected, economic and subeconomic housing in the 1930s helped to create both racial separation and a sense of community between sectors of the working class. Yet, white working class women did not form a homogenous group, but rather consisted of different ethnic groups, occupations and classes. The Afrikaans speaking sector, formed a significant component of the industrial labour force especially in the leather, food and beverage and clothing industries. In a centre where white labour was favoured and marketed as an advantage to outside investors, they rapidly displaced coloured women. The female workforce was basically young, underpaid (especially in comparison to wages on the Rand) and temporary. While white women were still in evidence in other occupations such as domestic work and in the informal sector, their numbers here steadily diminished as both racial segregation and municipal regulation, were implemented. Against a background of chaotic social conditions, large slum areas and the spread of infectious diseases, the local council did much to improve health services particularly for women and children. Poor relief instituted in 1919 was, however, less forthcoming and female - headed households were often left to rely on the services of local welfare organisations. The extended family, however, was the norm affording support against atomization. Although pressurised by social ills throughout the period, the family was increasingly buttressed by state assistance. Prevailing morality was likewise actively constructed in terms of legislative repression and racial division. This often lead to social aberrations such as infanticide which was only reduced by the increase of state assistance and, in the longer term, social mobility of the whites.
- Full Text:
- Date Issued: 1998
A study of the transdermal drug diffusion properties of rooperol tetra-acetate
- Authors: Pefile, Sibongile C.
- Date: 1998 , 2013-08-29
- Subjects: Transdermal medication , Skin absorption , Dermatologic agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3838 , http://hdl.handle.net/10962/d1007649 , Transdermal medication , Skin absorption , Dermatologic agents
- Description: The rapidly growing interest in the potential use of topical drug delivery formulations has resulted in increased use of the skin as a vital port for drug delivery. Extensive research has been conducted in designing vehicles capable of delivering a desired amount of drug to a specific site, to produce the desired pharmacological response. Rooperol tetra-acetate is a lipophilic, cytotoxic drug with the potential for use in the treatment of solar keratosis. For effective pharmacological action, delivery of the drug to the epidermal/dermal junction of the skin is required. A study of the topical penetration properties of rooperol tetra-acetate from different topical bases, each possessing different physico-chemical properties, was performed. The assessment involved a comparison of the diffusion properties under occlusive and non occlusive conditions when the drug was formulated into a gel, Cetomacrogol Cream B.P. (oil-inwater), Simple Ointment B.P. and an extemporaneously prepared water-in-oil topical cream. The in vitro experiments were conducted using polydimethylsiloxane and rat membrane mounted in a Franz diffusion cell. The topical permeation kinetics of rooperol tetra-acetate were determined by exploring the release characteristics of the active ingredient from the vehicles formulated and the permeability properties of the drug through the membranes employed. Further studies involved investigating the utilization of supersaturated systems intended to increase the thermodynamic activity of the drug when formulated into a propylene glycol/water vehicle (with and without polymer). To measure the release of rooperol tetra-acetate into the skin from a topical base it was necessary to, firstly, develop a suitable quantitative method for the analysis of the active drug in the aqueous receptor phase of in vitro diffusion cells. The second stage of product development was the design of an effective delivery system to facilitate the release of the diffusant from its base. A high performance liquid chromatographic method was utilized for the identification and quantification of the active drug. As validation is an important aspect in the development and subsequent utilization of an analytical procedure, the developed HPLC technique was validated by determining the precision, accuracy, range, limit of quantitation and sensitivity of the system. Lastly, the stability of rooperol tetra-acetate at elevated temperatures was assessed and a stability profile of the drug was generated for the three-month period of analysis. The results obtained following chromatographic analysis of the receptor phase sampled during the diffusion experiments indicate that the gel and oil-in-water formulations most effectively promoted the diffusion of rooperol tetra-acetate across polydimethylsiloxane membrane. The water-in-oil system exhibited lower flux rates and the ointment showed the least drug release. Occlusion of the topical vehicle increased the diffusitivity of the permeant from all formulations analysed. The permeation assessment results of the supersaturated systems showed enhanced diffusion of rooperol tetra-acetate across polydimethylsiloxane and rat membrane. The high thermodynamic activity existing in supersaturated systems most effectively increased the driving force for drug diffusion resulting in enhanced percutaneous penetration of rooperol tetra-acetate beyond the release and transport limitations of saturated solutions. These results provide the basis on which an effective topical drug delivery vehicle may be designed for this new drug entity.
- Full Text:
- Date Issued: 1998
- Authors: Pefile, Sibongile C.
- Date: 1998 , 2013-08-29
- Subjects: Transdermal medication , Skin absorption , Dermatologic agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3838 , http://hdl.handle.net/10962/d1007649 , Transdermal medication , Skin absorption , Dermatologic agents
- Description: The rapidly growing interest in the potential use of topical drug delivery formulations has resulted in increased use of the skin as a vital port for drug delivery. Extensive research has been conducted in designing vehicles capable of delivering a desired amount of drug to a specific site, to produce the desired pharmacological response. Rooperol tetra-acetate is a lipophilic, cytotoxic drug with the potential for use in the treatment of solar keratosis. For effective pharmacological action, delivery of the drug to the epidermal/dermal junction of the skin is required. A study of the topical penetration properties of rooperol tetra-acetate from different topical bases, each possessing different physico-chemical properties, was performed. The assessment involved a comparison of the diffusion properties under occlusive and non occlusive conditions when the drug was formulated into a gel, Cetomacrogol Cream B.P. (oil-inwater), Simple Ointment B.P. and an extemporaneously prepared water-in-oil topical cream. The in vitro experiments were conducted using polydimethylsiloxane and rat membrane mounted in a Franz diffusion cell. The topical permeation kinetics of rooperol tetra-acetate were determined by exploring the release characteristics of the active ingredient from the vehicles formulated and the permeability properties of the drug through the membranes employed. Further studies involved investigating the utilization of supersaturated systems intended to increase the thermodynamic activity of the drug when formulated into a propylene glycol/water vehicle (with and without polymer). To measure the release of rooperol tetra-acetate into the skin from a topical base it was necessary to, firstly, develop a suitable quantitative method for the analysis of the active drug in the aqueous receptor phase of in vitro diffusion cells. The second stage of product development was the design of an effective delivery system to facilitate the release of the diffusant from its base. A high performance liquid chromatographic method was utilized for the identification and quantification of the active drug. As validation is an important aspect in the development and subsequent utilization of an analytical procedure, the developed HPLC technique was validated by determining the precision, accuracy, range, limit of quantitation and sensitivity of the system. Lastly, the stability of rooperol tetra-acetate at elevated temperatures was assessed and a stability profile of the drug was generated for the three-month period of analysis. The results obtained following chromatographic analysis of the receptor phase sampled during the diffusion experiments indicate that the gel and oil-in-water formulations most effectively promoted the diffusion of rooperol tetra-acetate across polydimethylsiloxane membrane. The water-in-oil system exhibited lower flux rates and the ointment showed the least drug release. Occlusion of the topical vehicle increased the diffusitivity of the permeant from all formulations analysed. The permeation assessment results of the supersaturated systems showed enhanced diffusion of rooperol tetra-acetate across polydimethylsiloxane and rat membrane. The high thermodynamic activity existing in supersaturated systems most effectively increased the driving force for drug diffusion resulting in enhanced percutaneous penetration of rooperol tetra-acetate beyond the release and transport limitations of saturated solutions. These results provide the basis on which an effective topical drug delivery vehicle may be designed for this new drug entity.
- Full Text:
- Date Issued: 1998
A survey of the development of pitch perception theories, their application to bell sounds and an investigation of perceived differences between ringing and chiming bells
- Authors: Botha, Alison
- Date: 1998
- Subjects: Music -- Acoustics and physics , Musical pitch , Change ringing , Chimes , Bells
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:2631 , http://hdl.handle.net/10962/d1002296 , Music -- Acoustics and physics , Musical pitch , Change ringing , Chimes , Bells
- Description: A brief overview of the workings of the human auditory system is followed by a review of literature concerning both the theories and experimental investigations of human pitch perception. The application of these theories to the inharmonic complex tones produced by bells is discussed, and further experiments using bell sounds are reviewed. A methodology for psychoacoustic experiments with specific reference to those investigating pitch perception of inharmonic complex tones is presented. This methodology is then implemented in an experimental investigation of pitch perception of ringing and chiming bell sounds. A pitch matching experiment using ringing and chiming sounds from four bells aimed to determine perceived pitch differences between ringing and chiming bells. This experiment was inconclusive because insufficient data was collected. Known experimental results, such as the inability of non-musicians to match the pitches of sounds with different timbres were confirmed. Spectral analyses of the stimuli were performed. The presentation of stimuli at a low level of sensation is questioned, as this might have prevented pseudo high frequency noise resulting from stronger upper partials in the ringing sound from being audible, and hence the pitch differences between ringing and chiming bells would not be observed.
- Full Text:
- Date Issued: 1998
- Authors: Botha, Alison
- Date: 1998
- Subjects: Music -- Acoustics and physics , Musical pitch , Change ringing , Chimes , Bells
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:2631 , http://hdl.handle.net/10962/d1002296 , Music -- Acoustics and physics , Musical pitch , Change ringing , Chimes , Bells
- Description: A brief overview of the workings of the human auditory system is followed by a review of literature concerning both the theories and experimental investigations of human pitch perception. The application of these theories to the inharmonic complex tones produced by bells is discussed, and further experiments using bell sounds are reviewed. A methodology for psychoacoustic experiments with specific reference to those investigating pitch perception of inharmonic complex tones is presented. This methodology is then implemented in an experimental investigation of pitch perception of ringing and chiming bell sounds. A pitch matching experiment using ringing and chiming sounds from four bells aimed to determine perceived pitch differences between ringing and chiming bells. This experiment was inconclusive because insufficient data was collected. Known experimental results, such as the inability of non-musicians to match the pitches of sounds with different timbres were confirmed. Spectral analyses of the stimuli were performed. The presentation of stimuli at a low level of sensation is questioned, as this might have prevented pseudo high frequency noise resulting from stronger upper partials in the ringing sound from being audible, and hence the pitch differences between ringing and chiming bells would not be observed.
- Full Text:
- Date Issued: 1998
A synthetic and spectrometric study of the initial phases in urea-formaldehyde resin formation
- Authors: Nocanda, Xolani Wittleton
- Date: 1998
- Subjects: Phenolic resins , Gums and resins, Synthetic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4383 , http://hdl.handle.net/10962/d1005048 , Phenolic resins , Gums and resins, Synthetic
- Description: In a series ofpreIiminary studies of urea-formaldehyde reactions, the influence of the U:F molar ratio, the temperature and the catalyst were investigated. Subsequently, in a more rigorous evaluation of the influence of four variables on urea-formaldehyde resin formation, viz., U:F molar ratio, pH, temperature and reaction time, a set of twenty reactions were performed using a statistical approach. The results indicate that high resin viscosity is best achieved by using a high U:F molar ratio (1:2) and conducting the reaction at 90°C. Several basic components produced in urea-formaldehyde reactions have been synthesised, characterised by NMR spectroscopy, silylated using bis(trimethylsilyl)trifluoroacetamide and analysed by low resolution mass spectrometry. The use oftriazones as cross-linking agents has been investigated, and a series of 5-substituted triazones have been prepared and their mass fragmentation patterns explored using a combination of low and high resolution mass spectrometry. In order to facilitate interpretation of ¹³C NMR data obtained for U-F resins, internal rotation in various urea derivatives was investigated using variable temperature ¹H and ¹³C NMR spectroscopic study. Signal splittings observed below 247 K have been rationalised in terms of various rotameric structures.
- Full Text:
- Date Issued: 1998
- Authors: Nocanda, Xolani Wittleton
- Date: 1998
- Subjects: Phenolic resins , Gums and resins, Synthetic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4383 , http://hdl.handle.net/10962/d1005048 , Phenolic resins , Gums and resins, Synthetic
- Description: In a series ofpreIiminary studies of urea-formaldehyde reactions, the influence of the U:F molar ratio, the temperature and the catalyst were investigated. Subsequently, in a more rigorous evaluation of the influence of four variables on urea-formaldehyde resin formation, viz., U:F molar ratio, pH, temperature and reaction time, a set of twenty reactions were performed using a statistical approach. The results indicate that high resin viscosity is best achieved by using a high U:F molar ratio (1:2) and conducting the reaction at 90°C. Several basic components produced in urea-formaldehyde reactions have been synthesised, characterised by NMR spectroscopy, silylated using bis(trimethylsilyl)trifluoroacetamide and analysed by low resolution mass spectrometry. The use oftriazones as cross-linking agents has been investigated, and a series of 5-substituted triazones have been prepared and their mass fragmentation patterns explored using a combination of low and high resolution mass spectrometry. In order to facilitate interpretation of ¹³C NMR data obtained for U-F resins, internal rotation in various urea derivatives was investigated using variable temperature ¹H and ¹³C NMR spectroscopic study. Signal splittings observed below 247 K have been rationalised in terms of various rotameric structures.
- Full Text:
- Date Issued: 1998
Ammophila arenaria (L.) Link (marram grass) in South Africa and its potential invasiveness
- Authors: Hertling, Ursula Margret
- Date: 1998
- Subjects: Grasses -- South Africa Alien plants -- South Africa Sand dune plants -- South Africa Grasses -- Ecology -- South Africa Sand dune ecology -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4198 , http://hdl.handle.net/10962/d1003767
- Description: Ammophila arenaria (L.) Link is a European sand binding plant which was introduced to South Africa in the 1870's for the purpose of dune stabilisation. Because of its known invasiveness along the west coast of North America, and the problems South African ecosystems experience with alien invader plants, it was deemed necessary to study the biology and ecology of this species in South Africa. The aim of this thesis is to establish the potential invasiveness of A. arenaria on Cape coastal dunes and assess whether its use for dune stabilisation is still justifiable. A. arenaria occurs nowadays between the Langebaan area on the west coast and Gonubie in the Eastern Cape. Although widespread, the grass appears to occur only in areas where it has been planted. Its unaided spread may be prevented by adverse climatic conditions. Studies on the community biology of South African A. arenaria communities as compared to indigenous dune plant communities and natural A. arenaria communities in Europe cannot confirm the aggressive behaviour that A. arenaria shows in California and Oregon. In South Africa, A. arenaria does not exert strong floristic control over other species or outcompete and replace them, neither does it alter the topography of South African beaches and dunes. It forms weaker species associations and tends to develop communities of little species variability along the coast, thereby proving its alienness in South Africa, but this does not imply its invasiveness. Studies on succession of A. arenaria stabilisation areas show that monospecific A. arenaria plantings can be succeeded by a species-rich indigenous dune scrub or dune fynbos within a few decades. Plant-parasitic nematodes have been recorded, which may play an important role in the succession of A. arenaria stands in South Africa as was observed in Europe. Monitoring of A. arenaria communities and indigenous communities over nearly three years shows that A. arenaria is not spreading and replacing indigenous plants but in fact rather being replaced by the latter. A. arenaria profits from a superior sand burial tolerance but is affected by adverse climatic factors, mostly the lack of rainfall and strong radiation. In comparison to the indigenous dune grasses Thinopyrum distichum and Ehrharta villosa, it does not show any superior demographic traits such as an unusually high growth rate or large aboveground biomass production. Although A. arenaria produces viable seed in South Africa, the indigenous grasses show better germination and seedling establishment in the field. This study indicates that A. arenaria is not invasive in South Africa, nor likely to become an invader species in the near future. However, more research is required to confirm these results and more caution recommended regarding the further use of this alien grass for dune stabilisation.
- Full Text:
- Date Issued: 1998
- Authors: Hertling, Ursula Margret
- Date: 1998
- Subjects: Grasses -- South Africa Alien plants -- South Africa Sand dune plants -- South Africa Grasses -- Ecology -- South Africa Sand dune ecology -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4198 , http://hdl.handle.net/10962/d1003767
- Description: Ammophila arenaria (L.) Link is a European sand binding plant which was introduced to South Africa in the 1870's for the purpose of dune stabilisation. Because of its known invasiveness along the west coast of North America, and the problems South African ecosystems experience with alien invader plants, it was deemed necessary to study the biology and ecology of this species in South Africa. The aim of this thesis is to establish the potential invasiveness of A. arenaria on Cape coastal dunes and assess whether its use for dune stabilisation is still justifiable. A. arenaria occurs nowadays between the Langebaan area on the west coast and Gonubie in the Eastern Cape. Although widespread, the grass appears to occur only in areas where it has been planted. Its unaided spread may be prevented by adverse climatic conditions. Studies on the community biology of South African A. arenaria communities as compared to indigenous dune plant communities and natural A. arenaria communities in Europe cannot confirm the aggressive behaviour that A. arenaria shows in California and Oregon. In South Africa, A. arenaria does not exert strong floristic control over other species or outcompete and replace them, neither does it alter the topography of South African beaches and dunes. It forms weaker species associations and tends to develop communities of little species variability along the coast, thereby proving its alienness in South Africa, but this does not imply its invasiveness. Studies on succession of A. arenaria stabilisation areas show that monospecific A. arenaria plantings can be succeeded by a species-rich indigenous dune scrub or dune fynbos within a few decades. Plant-parasitic nematodes have been recorded, which may play an important role in the succession of A. arenaria stands in South Africa as was observed in Europe. Monitoring of A. arenaria communities and indigenous communities over nearly three years shows that A. arenaria is not spreading and replacing indigenous plants but in fact rather being replaced by the latter. A. arenaria profits from a superior sand burial tolerance but is affected by adverse climatic factors, mostly the lack of rainfall and strong radiation. In comparison to the indigenous dune grasses Thinopyrum distichum and Ehrharta villosa, it does not show any superior demographic traits such as an unusually high growth rate or large aboveground biomass production. Although A. arenaria produces viable seed in South Africa, the indigenous grasses show better germination and seedling establishment in the field. This study indicates that A. arenaria is not invasive in South Africa, nor likely to become an invader species in the near future. However, more research is required to confirm these results and more caution recommended regarding the further use of this alien grass for dune stabilisation.
- Full Text:
- Date Issued: 1998