Recent African derivation of Chrysomya putoria from C. chloropyga and mitochondrial DNA paraphyly of cytochrome oxidase subunit one in blowflies of forensic importance
- Wells, J D, Lunt, N, Villet, Martin H
- Authors: Wells, J D , Lunt, N , Villet, Martin H
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6888 , http://hdl.handle.net/10962/d1011648
- Description: Chrysomya chloropyga (Wiedemann) and C. putoria (Wiedemann) (Diptera: Calliphoridae) are closely related Afrotropical blowflies that breed in carrion and latrines, reaching high density in association with humans and spreading to other continents. In some cases of human death, Chyrsomya specimens provide forensic clues. Because the immature stages of such flies are often difficult to identify taxonomically, it is useful to develop DNA-based tests for specimen identification. Therefore we attempted to distinguish between C. chloropyga and C. putoria using mitochondrial DNA (mtDNA) sequence data from a 593-bp region of the gene for cytochrome oxidase subunit one (COI). Twelve specimens from each species yielded a total of five haplotypes, none being unique to C. putoria. Therefore it was not possible to distinguish between the two species using this locus. Maximum parsimony analysis indicated paraphyletic C. chloropyga mtDNA with C. putoria nested therein. Based on these and previously published data, we infer that C. putoria diverged very recently from C. chloropyga.
- Full Text:
- Date Issued: 2004
- Authors: Wells, J D , Lunt, N , Villet, Martin H
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6888 , http://hdl.handle.net/10962/d1011648
- Description: Chrysomya chloropyga (Wiedemann) and C. putoria (Wiedemann) (Diptera: Calliphoridae) are closely related Afrotropical blowflies that breed in carrion and latrines, reaching high density in association with humans and spreading to other continents. In some cases of human death, Chyrsomya specimens provide forensic clues. Because the immature stages of such flies are often difficult to identify taxonomically, it is useful to develop DNA-based tests for specimen identification. Therefore we attempted to distinguish between C. chloropyga and C. putoria using mitochondrial DNA (mtDNA) sequence data from a 593-bp region of the gene for cytochrome oxidase subunit one (COI). Twelve specimens from each species yielded a total of five haplotypes, none being unique to C. putoria. Therefore it was not possible to distinguish between the two species using this locus. Maximum parsimony analysis indicated paraphyletic C. chloropyga mtDNA with C. putoria nested therein. Based on these and previously published data, we infer that C. putoria diverged very recently from C. chloropyga.
- Full Text:
- Date Issued: 2004
Hill of Fools: a South African Romeo and Juliet?
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7039 , http://hdl.handle.net/10962/d1007377 , http://hdl.handle.net/10520/EJC47866
- Description: preprint , What kind of debt does Hill of Fools owe to Shakespeare? Look up ‘Peteni’ in the Companion to South African English Literature (1986) and you will be told that Hill of Fools is “loosely based on the story of Romeo and Juliet” (155). Scan the first newspaper reviews (see “The Early Reception of Hill of Fools” in this volume) and it is noticeable that a great many journalists focus on the Shakespeare connection as a means of introducing the book to their readers. One of the publisher’s readers, Henry Chakava, urged before publication that once all references to tribe or tribalism had been excised “the result will be a Romeo and Juliet type story much more superior to Weep Not Child.” The author himself reportedly described the book as “a black Romeo and Juliet drama” (Tribune Reporter 1988). And, indeed, some kind of parallel is patent to anyone who reads Hill of Fools with Shakespeare’s play in mind.
- Full Text:
- Date Issued: 2004
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7039 , http://hdl.handle.net/10962/d1007377 , http://hdl.handle.net/10520/EJC47866
- Description: preprint , What kind of debt does Hill of Fools owe to Shakespeare? Look up ‘Peteni’ in the Companion to South African English Literature (1986) and you will be told that Hill of Fools is “loosely based on the story of Romeo and Juliet” (155). Scan the first newspaper reviews (see “The Early Reception of Hill of Fools” in this volume) and it is noticeable that a great many journalists focus on the Shakespeare connection as a means of introducing the book to their readers. One of the publisher’s readers, Henry Chakava, urged before publication that once all references to tribe or tribalism had been excised “the result will be a Romeo and Juliet type story much more superior to Weep Not Child.” The author himself reportedly described the book as “a black Romeo and Juliet drama” (Tribune Reporter 1988). And, indeed, some kind of parallel is patent to anyone who reads Hill of Fools with Shakespeare’s play in mind.
- Full Text:
- Date Issued: 2004
Rhodes University Research Report 2004
- Authors: Rhodes University
- Date: 2004
- Language: English
- Type: Text
- Identifier: vital:559 , http://hdl.handle.net/10962/d1011950
- Description: [From Introduction] Rhodes University has had another successful year in terms of research activities and outputs in what has been an exciting Centenary year and I would like to add my congratulations and thanks to those of the Vice-Chancellor to all staff and postgraduate students for their research efforts in 2004. This report documents the research highlights and outputs in its many forms during 2004. Research which is not disseminated in this manner is wasted and I would like to encourage all staff and students to continue to publish their research in the most appropriate way. I would particularly like to stress the importance of publishing research findings in subsidy earning journals and of converting conference papers into journal articles where possible. Outputs in accredited journals are one of the principle means by which the University earns research subsidy and increasing the subsidy earned in this way will directly benefit internally funded research activities. In terms of journal publications 2004 has been a very good year with the audited but still to be awarded journal units increasing to 202 units from 165 awarded in 2003. I am confident that this is a sustainable trend and it is particularly encouraging in the context of a national trend of declining research outputs. A particularly successful publication was the special edition of the SA Journal of Science which was dedicated to the Rhodes University Centenary. I would like to thank all of those staff and students who submitted articles for publication in this edition and Professor Barker for initiating and co-ordinating this publication. An aspect of research outputs which remains a serious concern is the continued poor recognition by the Department of Education of publications in the form of books, chapters, refereed conference proceedings and patents. Not only are a small fraction of these outputs accepted for subsidy purposes but to date no feedback has been given in terms of which books, chapters, etc have in fact been subsidised or why the majority of submissions are not accepted. The Department of Education has, however, indicated that such feedback will be forthcoming from 2005. A further, and possibly even more problematic, aspect of recognition of research outputs (and NRF rating) is the inability to assess outputs in the Performing and Visual Arts. Attempts have been made to address this issue at a national level but no solution appears to be likely in the near future. A concerted and unified national approach to addressing the issue of recognition of research outputs other than articles in accredited journals is urgently needed at the highest level if the research efforts in many disciplines are not to be undermined. My thanks once again to all staff and students for their continued commitment to research.
- Full Text:
- Date Issued: 2004
- Authors: Rhodes University
- Date: 2004
- Language: English
- Type: Text
- Identifier: vital:559 , http://hdl.handle.net/10962/d1011950
- Description: [From Introduction] Rhodes University has had another successful year in terms of research activities and outputs in what has been an exciting Centenary year and I would like to add my congratulations and thanks to those of the Vice-Chancellor to all staff and postgraduate students for their research efforts in 2004. This report documents the research highlights and outputs in its many forms during 2004. Research which is not disseminated in this manner is wasted and I would like to encourage all staff and students to continue to publish their research in the most appropriate way. I would particularly like to stress the importance of publishing research findings in subsidy earning journals and of converting conference papers into journal articles where possible. Outputs in accredited journals are one of the principle means by which the University earns research subsidy and increasing the subsidy earned in this way will directly benefit internally funded research activities. In terms of journal publications 2004 has been a very good year with the audited but still to be awarded journal units increasing to 202 units from 165 awarded in 2003. I am confident that this is a sustainable trend and it is particularly encouraging in the context of a national trend of declining research outputs. A particularly successful publication was the special edition of the SA Journal of Science which was dedicated to the Rhodes University Centenary. I would like to thank all of those staff and students who submitted articles for publication in this edition and Professor Barker for initiating and co-ordinating this publication. An aspect of research outputs which remains a serious concern is the continued poor recognition by the Department of Education of publications in the form of books, chapters, refereed conference proceedings and patents. Not only are a small fraction of these outputs accepted for subsidy purposes but to date no feedback has been given in terms of which books, chapters, etc have in fact been subsidised or why the majority of submissions are not accepted. The Department of Education has, however, indicated that such feedback will be forthcoming from 2005. A further, and possibly even more problematic, aspect of recognition of research outputs (and NRF rating) is the inability to assess outputs in the Performing and Visual Arts. Attempts have been made to address this issue at a national level but no solution appears to be likely in the near future. A concerted and unified national approach to addressing the issue of recognition of research outputs other than articles in accredited journals is urgently needed at the highest level if the research efforts in many disciplines are not to be undermined. My thanks once again to all staff and students for their continued commitment to research.
- Full Text:
- Date Issued: 2004
An assessment of the performance appraisal system utilised for junior and middle level management within the South African National Defence Force
- Authors: Terblanche, Graham Martin
- Date: 2004
- Subjects: Middle managers -- Rating of -- South Africa , South Africa. National Defence Force Officials and employees Rating of
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10884 , http://hdl.handle.net/10948/148 , Middle managers -- Rating of -- South Africa , South Africa. National Defence Force Officials and employees Rating of
- Description: The research problem of this study was to assess the extent to which the appraisal system for junior and middle level managers in the South African National Defence Force (SANDF) met the requirements and guidelines for performance appraisal as stipulated in the literature. To achieve this objective, the following procedure was followed: · A survey of existing literature, related to performance appraisal, was conducted. The literature study focused on the requirements for an effective performance appraisal system, appraisal methods and appraisal errors. Attention was also focused on who should take responsibility for performance appraisal and the importance of regularly evaluating the performance appraisal system to meet the demands of a changing environment. The second part of the literature study dealt with the guidelines for establishing an effective appraisal system as well as performance management processes and cycles that are critical for the effectiveness of an appraisal system. The theoretical study formed the basis for the development of a survey questionnaire to establish the extent to which junior and middle level managers in the SANDF agreed with the theoretical guidelines. The survey was administered to a randomly selected group of junior and middle level managers who were representative of the South African Army, Airforce and Medical Services. The empirical results indicated that there was concurrence with many of the guidelines in the literature, but that there were areas that could be improved. It became evident that many respondents felt that the current system was not entirely fair and was not adapted to meet the needs of the integrated SANDF. Specifically, results indicated that the system should be re-evaluated to eliminate bias and to enhance the development of clear standards, both on a quantitative and qualitative level. It became clear that training and communication were important to the successful development and utilisation of a performance appraisal system. An effective performance appraisal system that is integrated with the overall performance management system of an organisation will enhance productivity, satisfaction and the attainment of goals.
- Full Text:
- Date Issued: 2004
- Authors: Terblanche, Graham Martin
- Date: 2004
- Subjects: Middle managers -- Rating of -- South Africa , South Africa. National Defence Force Officials and employees Rating of
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10884 , http://hdl.handle.net/10948/148 , Middle managers -- Rating of -- South Africa , South Africa. National Defence Force Officials and employees Rating of
- Description: The research problem of this study was to assess the extent to which the appraisal system for junior and middle level managers in the South African National Defence Force (SANDF) met the requirements and guidelines for performance appraisal as stipulated in the literature. To achieve this objective, the following procedure was followed: · A survey of existing literature, related to performance appraisal, was conducted. The literature study focused on the requirements for an effective performance appraisal system, appraisal methods and appraisal errors. Attention was also focused on who should take responsibility for performance appraisal and the importance of regularly evaluating the performance appraisal system to meet the demands of a changing environment. The second part of the literature study dealt with the guidelines for establishing an effective appraisal system as well as performance management processes and cycles that are critical for the effectiveness of an appraisal system. The theoretical study formed the basis for the development of a survey questionnaire to establish the extent to which junior and middle level managers in the SANDF agreed with the theoretical guidelines. The survey was administered to a randomly selected group of junior and middle level managers who were representative of the South African Army, Airforce and Medical Services. The empirical results indicated that there was concurrence with many of the guidelines in the literature, but that there were areas that could be improved. It became evident that many respondents felt that the current system was not entirely fair and was not adapted to meet the needs of the integrated SANDF. Specifically, results indicated that the system should be re-evaluated to eliminate bias and to enhance the development of clear standards, both on a quantitative and qualitative level. It became clear that training and communication were important to the successful development and utilisation of a performance appraisal system. An effective performance appraisal system that is integrated with the overall performance management system of an organisation will enhance productivity, satisfaction and the attainment of goals.
- Full Text:
- Date Issued: 2004
Irony and transcendence on the Renaissance stage
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7067 , http://hdl.handle.net/10962/d1007455 , https://doi.org/10.1484/M.CURSOR-EB.3.4728
- Description: preprint , This is the concluding essay in a collection entitled 'This Earthly Stage'. The chapter argues that the peculiar task of the stage metaphor - the notion of the theatre as a metaphor for life,which involves complex interactions between rarefied intellectual constructions of life and mundane reality - is to interrogate the tension between an inscrutable cosmic order and the limited viewpoints of ordinary humanity.The piece moves from general considerations of irony and dramatic irony, via an analysis of Kyd's The Spanish Tragedy, to comments on Petrarch, Pico and Vives, culminating in a consideration of irony and transcendence in Shakespeare's last plays.
- Full Text:
- Date Issued: 2004
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7067 , http://hdl.handle.net/10962/d1007455 , https://doi.org/10.1484/M.CURSOR-EB.3.4728
- Description: preprint , This is the concluding essay in a collection entitled 'This Earthly Stage'. The chapter argues that the peculiar task of the stage metaphor - the notion of the theatre as a metaphor for life,which involves complex interactions between rarefied intellectual constructions of life and mundane reality - is to interrogate the tension between an inscrutable cosmic order and the limited viewpoints of ordinary humanity.The piece moves from general considerations of irony and dramatic irony, via an analysis of Kyd's The Spanish Tragedy, to comments on Petrarch, Pico and Vives, culminating in a consideration of irony and transcendence in Shakespeare's last plays.
- Full Text:
- Date Issued: 2004
An introduction: Peteni in context
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7036 , http://hdl.handle.net/10962/d1007372 , http://hdl.handle.net/10520/EJC47870
- Description: preprint , It is rare for a writer to make a literary impact with only one novel. It is even more unusual when that work is written by a novice author in his early sixties. Yet such is the case of R.L. Peteni, whose novel, Hill of Fools, was published by David Philip in South Africa in 1976, and internationally in the same year by Heinemann in the African Writers Series. Four years later, in 1980, the book was translated by the author into Xhosa as Kwazidenge and published by the Lovedale Press. Twenty years after initial publication, in 1996, there came a television version of Kwazidenge broadcast by the SABC, starring Willie Thambo and Amanda Quwe, though the locale was translated – in the bizarre logic of television – to an urban environment on the Cape Flats. The transposition, though pragmatic in terms of television demographics, destroyed much of the point of Peteni’s work, for Hill of Fools is South Africa’s first regional novel in English by a black writer. It is also the first novel in English by a Xhosa-speaker.
- Full Text:
- Date Issued: 2004
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7036 , http://hdl.handle.net/10962/d1007372 , http://hdl.handle.net/10520/EJC47870
- Description: preprint , It is rare for a writer to make a literary impact with only one novel. It is even more unusual when that work is written by a novice author in his early sixties. Yet such is the case of R.L. Peteni, whose novel, Hill of Fools, was published by David Philip in South Africa in 1976, and internationally in the same year by Heinemann in the African Writers Series. Four years later, in 1980, the book was translated by the author into Xhosa as Kwazidenge and published by the Lovedale Press. Twenty years after initial publication, in 1996, there came a television version of Kwazidenge broadcast by the SABC, starring Willie Thambo and Amanda Quwe, though the locale was translated – in the bizarre logic of television – to an urban environment on the Cape Flats. The transposition, though pragmatic in terms of television demographics, destroyed much of the point of Peteni’s work, for Hill of Fools is South Africa’s first regional novel in English by a black writer. It is also the first novel in English by a Xhosa-speaker.
- Full Text:
- Date Issued: 2004
Learners' perceptions of creating a collaborative hypermedia product: an exploratory case study at Mount Pleasant Primary School
- Authors: du Plessis, André
- Date: 2004
- Subjects: Computer-assisted instruction -- South Africa Computers -- Study and teaching -- South Africa Education, Elementary -- Activity programs Competency-based education -- South Africa Educational technology -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1663 , http://hdl.handle.net/10962/d1003546
- Description: The Ministry of Education (SICTE, 2002) states that the widespread introduction of computers in schools should support Curriculum 2005 and that computer technology is part and parcel of making schools the center of community life. The vision is to establish Smart Schools: schools that are reinvented in terms of teaching-learning practices to prepare learners for the information era (SICTE, 2002). Kafai (1996:71) has found that conventional school assignments rarely give learners the opportunity to spend a great deal of time on complex projects. As a result, many learners have little experience in design: planning, problem solving, researching, dealing with time constraints, modifying expectations and synthesizing everything in a project. Research by Carver, Lehrer, Connell and Erickson (1992); Lehrer, (1993); Lehrer, Erickson and Connell (1994); Kafai (1996); Liu and Hsiao (2002) and Liu (2002) indicates that the design of hypermedia artefacts can assist in providing experience in design. To date, no equivalent research has been conducted in South Africa to ascertain the perceptions of learners regarding the creation of a hypermedia artefact over an extended period of time and whether some of the critical outcomes specified in Curriculum 2005 can be addressed in such a learning-by-design hypermedia project. This study shows that design skills and aspects related to the critical outcomes of Curriculum 2005 can be achieved. Furthermore, it indicates that this kind of project encourages interest, motivation and collaboration. In addition, it suggests that learners experience the role of the teacher as different and prefer such a learning environment. In spite of the positive results, some aspects that need attention for future implementation are suggested.
- Full Text:
- Date Issued: 2004
- Authors: du Plessis, André
- Date: 2004
- Subjects: Computer-assisted instruction -- South Africa Computers -- Study and teaching -- South Africa Education, Elementary -- Activity programs Competency-based education -- South Africa Educational technology -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1663 , http://hdl.handle.net/10962/d1003546
- Description: The Ministry of Education (SICTE, 2002) states that the widespread introduction of computers in schools should support Curriculum 2005 and that computer technology is part and parcel of making schools the center of community life. The vision is to establish Smart Schools: schools that are reinvented in terms of teaching-learning practices to prepare learners for the information era (SICTE, 2002). Kafai (1996:71) has found that conventional school assignments rarely give learners the opportunity to spend a great deal of time on complex projects. As a result, many learners have little experience in design: planning, problem solving, researching, dealing with time constraints, modifying expectations and synthesizing everything in a project. Research by Carver, Lehrer, Connell and Erickson (1992); Lehrer, (1993); Lehrer, Erickson and Connell (1994); Kafai (1996); Liu and Hsiao (2002) and Liu (2002) indicates that the design of hypermedia artefacts can assist in providing experience in design. To date, no equivalent research has been conducted in South Africa to ascertain the perceptions of learners regarding the creation of a hypermedia artefact over an extended period of time and whether some of the critical outcomes specified in Curriculum 2005 can be addressed in such a learning-by-design hypermedia project. This study shows that design skills and aspects related to the critical outcomes of Curriculum 2005 can be achieved. Furthermore, it indicates that this kind of project encourages interest, motivation and collaboration. In addition, it suggests that learners experience the role of the teacher as different and prefer such a learning environment. In spite of the positive results, some aspects that need attention for future implementation are suggested.
- Full Text:
- Date Issued: 2004
Studies on parasitoids of the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), in South Africa
- Authors: Nofemela, Sicelo Robert
- Date: 2004
- Subjects: Plutellidae -- South Africa , Plutellidae -- Biological control , Plutellidae -- Parasites , Parasitoids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5780 , http://hdl.handle.net/10962/d1005468 , Plutellidae -- South Africa , Plutellidae -- Biological control , Plutellidae -- Parasites , Parasitoids
- Description: The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a major pest of Brassica crops in many parts of the world. Because of its ability to develop resistance to virtually all major groups of insecticides, including Bacillus thuringiensis Berliner (Bt), much attention has therefore been given to biological control using parasitoids. South Africa has an abundance of parasitoids attacking this pest. Cotesia plutellae (Kurdjumov) (Hymenoptera: Braconidae) is the most abundant larval parasitoid of P. xylostella in South Africa. In East Africa, its role in biological control of P. xylostella is insignificant, and the most abundant parasitoid there is Diadegma mollipla (Holmgren) (Hymenoptera: Ichneumonidae), a larvalpupal parasitoid. In South Africa, however, D. mollipla is out-competed by C. plutellae. Total parasitism of P. xylostella in East Africa rarely exceeds 15%, therefore there is a need to introduce more effective and heat-tolerant parasitoids of P. xylostella to that region. This study was therefore initiated to examine the potential of C. plutellae and D. mollipla as biological control agents by studying certain aspects of their biology in the laboratory, as well as the suitability of C. plutellae for introduction into East Africa. Biological aspects studied were: (i) host instar preference, fecundity, and searching efficiency of C. plutellae and D. mollipla at different host and parasitoid densities; (ii) effects of temperature on parasitism of P. xylostella by C. plutellae and D. mollipla, and on their rates of development and emergence. In addition, the role of parasitoids in controlling P. xylostella on unsprayed cabbage plots was investigated. Both C. plutellae and D. mollipla preferred to attack second and third instar hosts than fourth instars in choice and no-choice tests. However, D. mollipla attacked more fourth instar hosts than C. plutellae. Cotesia plutellae laid mainly female eggs in second and third instar hosts than in fourth instars, whereas D. mollipla laid more female eggs in fourth instar hosts than in second and third instar hosts. Diadegma mollipla was more fecund [82.57 ± 32.87, (mean ± s.d.) than C. plutellae (42.13 ± 12.2), and was long lived (7.13 ± 3.69 days) compared to the latter (5.23 ± 2.7 days). An increase in host density resulted in the reduction in the area of discovery (a) and the killing power (K) for both parasitoids. No significant differences were detected between the searching efficiency (t = -1.42NS, d.f. = 48, P < 0.001) of the two parasitoids. An increase in parasitoid density also resulted in a decline in searching efficiency, but not the killing power, of both parasitoids. Cotesia plutellae completed development at all temperatures tested (21-33°C), whereas D. mollipla completed development at temperatures from 18-30°C, and C. plutellae had a lower threshold for development (8.14°C) compared to D. mollipla (10.23°C). At all tested temperatures, the generation time for C. plutellae was shorter compared to D. mollipla. The possible reasons for the dominance of C. plutellae over D. mollipla in the field are: shorter generation time, high production of female progeny in younger hosts, low interference among searching females, and relatively wide thermal tolerance. The role of parasitoids in regulating diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), populations was studied for two years (February 2000-January 2002) on unsprayed cabbage fields at Brits, North West Province, South Africa. Cabbage seedlings were transplanted in three consecutive times each year. Cabbage infestations by P. xylostella larvae and pupae, and their parasitoids, were monitored at weekly intervals. The flight activity of P. xylostella male moths was monitored using sex-pheromone traps. Trap catches indicated that the moths were active throughout the year. The flight activity of the moths corresponded with infestations on the crop. Trap catches and infestation levels were generally low from December to August and high from September to November. Eight hymenopteran parasitoids were reared: the larval parasitoids Cotesia plutellae (Kurdjumov) (Braconidae) and Apanteles halfordi (Ullyett) (Braconidae); the larval-pupal parasitoids Oomyzus sokolowskii (Kurdjumov) (Eulophidae) and Diadegma mollipla (Holmgren)(Ichneumonidae); the pupal parasitoid Diadromus collaris (Gravenhorst) (Ichneumonidae); and the hyperparasitoids Eurytoma sp. (Eurytomidae), Mesochorus sp. (Ichneumonidae), and Pteromalus sp. (Pteromalidae). Cotesia plutellae was the most abundant parasitoid of P. xylostella followed by O. sokolowskii, D. collaris, A. halfordi and D. mollipla. Parasitism of P. xylostella larvae was high reaching 100% on several occasions during late spring to end of autumn (November-May) each year. Parasitism was lower (<50%) in winter and early spring (June-September). Apanteles halfordi was absent in winter but re-appeared in spring. Parasitism of P. xylostella pupae by D. collaris was high only during spring (September-October). Hyperparasitism was generally low except when primary parasitoids were abundant in spring (September-November) and summer (December-February) when up to 25% of P. xylostella larvae and C. plutellae cocoons yielded hyperparasitoids. The role of other biotic and abiotic mortality factors on the population dynamics of P. xylostella is discussed.
- Full Text:
- Date Issued: 2004
- Authors: Nofemela, Sicelo Robert
- Date: 2004
- Subjects: Plutellidae -- South Africa , Plutellidae -- Biological control , Plutellidae -- Parasites , Parasitoids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5780 , http://hdl.handle.net/10962/d1005468 , Plutellidae -- South Africa , Plutellidae -- Biological control , Plutellidae -- Parasites , Parasitoids
- Description: The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a major pest of Brassica crops in many parts of the world. Because of its ability to develop resistance to virtually all major groups of insecticides, including Bacillus thuringiensis Berliner (Bt), much attention has therefore been given to biological control using parasitoids. South Africa has an abundance of parasitoids attacking this pest. Cotesia plutellae (Kurdjumov) (Hymenoptera: Braconidae) is the most abundant larval parasitoid of P. xylostella in South Africa. In East Africa, its role in biological control of P. xylostella is insignificant, and the most abundant parasitoid there is Diadegma mollipla (Holmgren) (Hymenoptera: Ichneumonidae), a larvalpupal parasitoid. In South Africa, however, D. mollipla is out-competed by C. plutellae. Total parasitism of P. xylostella in East Africa rarely exceeds 15%, therefore there is a need to introduce more effective and heat-tolerant parasitoids of P. xylostella to that region. This study was therefore initiated to examine the potential of C. plutellae and D. mollipla as biological control agents by studying certain aspects of their biology in the laboratory, as well as the suitability of C. plutellae for introduction into East Africa. Biological aspects studied were: (i) host instar preference, fecundity, and searching efficiency of C. plutellae and D. mollipla at different host and parasitoid densities; (ii) effects of temperature on parasitism of P. xylostella by C. plutellae and D. mollipla, and on their rates of development and emergence. In addition, the role of parasitoids in controlling P. xylostella on unsprayed cabbage plots was investigated. Both C. plutellae and D. mollipla preferred to attack second and third instar hosts than fourth instars in choice and no-choice tests. However, D. mollipla attacked more fourth instar hosts than C. plutellae. Cotesia plutellae laid mainly female eggs in second and third instar hosts than in fourth instars, whereas D. mollipla laid more female eggs in fourth instar hosts than in second and third instar hosts. Diadegma mollipla was more fecund [82.57 ± 32.87, (mean ± s.d.) than C. plutellae (42.13 ± 12.2), and was long lived (7.13 ± 3.69 days) compared to the latter (5.23 ± 2.7 days). An increase in host density resulted in the reduction in the area of discovery (a) and the killing power (K) for both parasitoids. No significant differences were detected between the searching efficiency (t = -1.42NS, d.f. = 48, P < 0.001) of the two parasitoids. An increase in parasitoid density also resulted in a decline in searching efficiency, but not the killing power, of both parasitoids. Cotesia plutellae completed development at all temperatures tested (21-33°C), whereas D. mollipla completed development at temperatures from 18-30°C, and C. plutellae had a lower threshold for development (8.14°C) compared to D. mollipla (10.23°C). At all tested temperatures, the generation time for C. plutellae was shorter compared to D. mollipla. The possible reasons for the dominance of C. plutellae over D. mollipla in the field are: shorter generation time, high production of female progeny in younger hosts, low interference among searching females, and relatively wide thermal tolerance. The role of parasitoids in regulating diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), populations was studied for two years (February 2000-January 2002) on unsprayed cabbage fields at Brits, North West Province, South Africa. Cabbage seedlings were transplanted in three consecutive times each year. Cabbage infestations by P. xylostella larvae and pupae, and their parasitoids, were monitored at weekly intervals. The flight activity of P. xylostella male moths was monitored using sex-pheromone traps. Trap catches indicated that the moths were active throughout the year. The flight activity of the moths corresponded with infestations on the crop. Trap catches and infestation levels were generally low from December to August and high from September to November. Eight hymenopteran parasitoids were reared: the larval parasitoids Cotesia plutellae (Kurdjumov) (Braconidae) and Apanteles halfordi (Ullyett) (Braconidae); the larval-pupal parasitoids Oomyzus sokolowskii (Kurdjumov) (Eulophidae) and Diadegma mollipla (Holmgren)(Ichneumonidae); the pupal parasitoid Diadromus collaris (Gravenhorst) (Ichneumonidae); and the hyperparasitoids Eurytoma sp. (Eurytomidae), Mesochorus sp. (Ichneumonidae), and Pteromalus sp. (Pteromalidae). Cotesia plutellae was the most abundant parasitoid of P. xylostella followed by O. sokolowskii, D. collaris, A. halfordi and D. mollipla. Parasitism of P. xylostella larvae was high reaching 100% on several occasions during late spring to end of autumn (November-May) each year. Parasitism was lower (<50%) in winter and early spring (June-September). Apanteles halfordi was absent in winter but re-appeared in spring. Parasitism of P. xylostella pupae by D. collaris was high only during spring (September-October). Hyperparasitism was generally low except when primary parasitoids were abundant in spring (September-November) and summer (December-February) when up to 25% of P. xylostella larvae and C. plutellae cocoons yielded hyperparasitoids. The role of other biotic and abiotic mortality factors on the population dynamics of P. xylostella is discussed.
- Full Text:
- Date Issued: 2004
Politics, latent and overt, in Hill of Fools
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:7064 , http://hdl.handle.net/10962/d1007430
- Description: [From the text]: R. L. Peteni’s novel Hill of Fools (1976) is a work that benefits greatly when Collingwood’s maxim is observed. The author’s family history and the circumstances surrounding the book’s publication add a dimension of political and social meaning which its surface deliberately occludes. Perhaps more importantly, while the story can readily be enjoyed, the quality of sensibility behind the work is not readily accessed without understanding some of the socio-political background.
- Full Text:
- Date Issued: 2004
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:7064 , http://hdl.handle.net/10962/d1007430
- Description: [From the text]: R. L. Peteni’s novel Hill of Fools (1976) is a work that benefits greatly when Collingwood’s maxim is observed. The author’s family history and the circumstances surrounding the book’s publication add a dimension of political and social meaning which its surface deliberately occludes. Perhaps more importantly, while the story can readily be enjoyed, the quality of sensibility behind the work is not readily accessed without understanding some of the socio-political background.
- Full Text:
- Date Issued: 2004
The location decision of PE College after a merger
- Authors: Ferreira, Renee
- Date: 2004
- Subjects: Industrial location -- South Africa -- Port Elizabeth , School sites -- South Africa -- Port Elizabeth , Universities and colleges -- Mergers -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10863 , http://hdl.handle.net/10948/256 , Industrial location -- South Africa -- Port Elizabeth , School sites -- South Africa -- Port Elizabeth , Universities and colleges -- Mergers -- South Africa -- Port Elizabeth
- Description: The Port Elizabeth College (PE College) was founded in January 2002 as a result of the merger between the three technical colleges in Port Elizabeth, namely, Russell Road, Bethelsdorp and Iqhayiya. Similar courses are offered in duplicated facilities, contrary to the sentiment of the legislation requiring the reduction of the number of technical colleges from 152 to 50. A further problem experienced by the management of PE College is that the Russell Road campus is so full that it is necessary to turn prospective students away, while the other campuses are under-utilised. The focus of this study is the evaluation of the location and coverage offered by the six PE College sites of delivery. The study examined the physical facilities of the PE College and investigated the requirements of staff and students, regarding their campuses of choice. The objectives were achieved through site visits to the six campuses, as well as a quantitative, structured, self-administered survey of all staff and students of the PE College in October 2003. The questions used in the survey were selected only after a literature review of location theory, which highlighted the factors to be considered in location decisions. Completed questionnaires were received from 1 256 student and 120 staff respondents. The empirical study showed that 13,2% of students and 9,2% of staff wished to study or work at a different campus. Sixty-eight percent of students who wanted to change campuses preferred to be based at the Russell Road campus, which is already full. As a result, this study has led to the recommendation that the PE College should use a product-based location strategy, where each campus specialises in a different field of study. Although this location strategy will not necessarily offer the greatest accessibility to students and staff, it will result in the least amount of duplication, and, therefore, reduced costs.
- Full Text:
- Date Issued: 2004
- Authors: Ferreira, Renee
- Date: 2004
- Subjects: Industrial location -- South Africa -- Port Elizabeth , School sites -- South Africa -- Port Elizabeth , Universities and colleges -- Mergers -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10863 , http://hdl.handle.net/10948/256 , Industrial location -- South Africa -- Port Elizabeth , School sites -- South Africa -- Port Elizabeth , Universities and colleges -- Mergers -- South Africa -- Port Elizabeth
- Description: The Port Elizabeth College (PE College) was founded in January 2002 as a result of the merger between the three technical colleges in Port Elizabeth, namely, Russell Road, Bethelsdorp and Iqhayiya. Similar courses are offered in duplicated facilities, contrary to the sentiment of the legislation requiring the reduction of the number of technical colleges from 152 to 50. A further problem experienced by the management of PE College is that the Russell Road campus is so full that it is necessary to turn prospective students away, while the other campuses are under-utilised. The focus of this study is the evaluation of the location and coverage offered by the six PE College sites of delivery. The study examined the physical facilities of the PE College and investigated the requirements of staff and students, regarding their campuses of choice. The objectives were achieved through site visits to the six campuses, as well as a quantitative, structured, self-administered survey of all staff and students of the PE College in October 2003. The questions used in the survey were selected only after a literature review of location theory, which highlighted the factors to be considered in location decisions. Completed questionnaires were received from 1 256 student and 120 staff respondents. The empirical study showed that 13,2% of students and 9,2% of staff wished to study or work at a different campus. Sixty-eight percent of students who wanted to change campuses preferred to be based at the Russell Road campus, which is already full. As a result, this study has led to the recommendation that the PE College should use a product-based location strategy, where each campus specialises in a different field of study. Although this location strategy will not necessarily offer the greatest accessibility to students and staff, it will result in the least amount of duplication, and, therefore, reduced costs.
- Full Text:
- Date Issued: 2004
"My novel, Hill of Fools"
- Peteni, R L, Wright, Laurence
- Authors: Peteni, R L , Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7038 , http://hdl.handle.net/10962/d1007376 , http://hdl.handle.net/10520/EJC47869
- Description: preprint , R.L. Peteni - 'There is a tendency in human beings to pay no heed to events in small remote areas. They would rather concern themselves only with those events which make headlines, with political upheavals and industrial conflicts centred in large metropolitan regions. Yet there is always drama and human conflict in the humblest rural village. In selecting a pastoral theme and small fictitious villages in an obscure corner of Keiskammahoek as the setting of the novel, I had an ironic intention. Themes illustrated in these obscure villages would, I believed, have more universal application than they would if I had selected a larger centre, identifiable personages and known political trends. I did not want anybody to sit back, complacent, feeling that the spotlight was on Lennox Sebe’s Ciskei alone, or Kaiser Matanzima’s Transkei, or John Vorster’s apartheid South Africa. The spotlight is on the Ciskei, yes, on Transkei, on South Africa, on any other country where public life and personal relationships are bedevilled by tribalism or racialism or any form of sectionalism.
- Full Text:
- Date Issued: 2004
- Authors: Peteni, R L , Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7038 , http://hdl.handle.net/10962/d1007376 , http://hdl.handle.net/10520/EJC47869
- Description: preprint , R.L. Peteni - 'There is a tendency in human beings to pay no heed to events in small remote areas. They would rather concern themselves only with those events which make headlines, with political upheavals and industrial conflicts centred in large metropolitan regions. Yet there is always drama and human conflict in the humblest rural village. In selecting a pastoral theme and small fictitious villages in an obscure corner of Keiskammahoek as the setting of the novel, I had an ironic intention. Themes illustrated in these obscure villages would, I believed, have more universal application than they would if I had selected a larger centre, identifiable personages and known political trends. I did not want anybody to sit back, complacent, feeling that the spotlight was on Lennox Sebe’s Ciskei alone, or Kaiser Matanzima’s Transkei, or John Vorster’s apartheid South Africa. The spotlight is on the Ciskei, yes, on Transkei, on South Africa, on any other country where public life and personal relationships are bedevilled by tribalism or racialism or any form of sectionalism.
- Full Text:
- Date Issued: 2004
Characterisation of the J domain aminoacid residues important for the interaction of DNAJ-like proteins with HSP70 chaperones
- Authors: Hennessy, Fritha
- Date: 2004
- Subjects: Heat shock proteins Protein folding Proteins -- Analysis Proteins -- Structure Molecular chaperones
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3937 , http://hdl.handle.net/10962/d1003996
- Description: The 70 kDa heat shock proteins (Hsp70s) are vital for normal protein folding, as they stabilise the unfolded state of nascent polypeptides, allowing these sufficient time to attain a correct tertiary structure. Hsp70s are aided by the DnaJ-like family of proteins, which interact with Hsp70s in order to enhance the chaperone activity of these proteins. DnaJ-like proteins contain a J domain, a seventy amino acid domain consisting of four α-helices, which is defined by the presence of an invariant tripeptide of histidine, proline and aspartic acid (HPD motif). This motif is key to the interaction between DnaJ-like proteins and Hsp70s. This thesis has focused on determining the presence of other conserved residues in the J domain and their role in mediating the interaction of DnaJ-like proteins with partner Hsp70s. DnaJ-like proteins from Agrobacterium tumefaciens RUOR were isolated and used as a model system. A. tumefaciens DnaJ (Agt DnaJ) was able to replace the lack of E. coli DnaJ in an E. coli null mutant strain, however, additional A. tumefaciens DnaJ-like proteins Agt DjC1/DjlA, Agt DjC2 and Agt DjC5 were unable to complement for the lack of E. coli DnaJ. Replacement of the Agt DnaJ J domain with J domains from these proteins resulted in non-functional chimeric proteins, despite some sequence conservation. The kinetics of the basal specific ATPase activity of Agt DnaK, and its ability to have this activity stimulated by Agt DnaJ and Agt DnaJ-H33Q were also investigated. Stimulation of the ATPase activity by Agt DnaJ ranged between 1.5 to 2 fold, but Agt DnaJ-H33Q was unable to stimulate the basal ATPase activity. Conserved amino acids in the J domain were identified in silico, and these residues were substituted in the J domain of Agt DnaJ. The ability of these derivative proteins to replace E. coli DnaJ was investigated. Alterations in the HPD motif gave rise to proteins unable to complement for lack of E. coli DnaJ, consistent with literature. Agt DnaJ-R26A was unable to replace E. coli DnaJ suggesting that Arg26 could be key to the interaction with partner Hsp70s. Agt DnaJ-D59A was unable to replace E. coli DnaJ; substitutions in Asp59 have not previously been shown to impact on the function of DnaJ. Substituting Arg63 in Agt DnaJ abrogated the levels of complementation. Substitution of several structural residues was also found to disrupt the in vivo function of Agt DnaJ suggesting that the maintenance of the structural integrity of the J domain was important for function. This study has identified a number of residues critical to the structure and function of the J domain of Agt DnaJ, and potentially of general importance as molecular determinants for DnaJ-Hsp70 interaction.
- Full Text:
- Date Issued: 2004
- Authors: Hennessy, Fritha
- Date: 2004
- Subjects: Heat shock proteins Protein folding Proteins -- Analysis Proteins -- Structure Molecular chaperones
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3937 , http://hdl.handle.net/10962/d1003996
- Description: The 70 kDa heat shock proteins (Hsp70s) are vital for normal protein folding, as they stabilise the unfolded state of nascent polypeptides, allowing these sufficient time to attain a correct tertiary structure. Hsp70s are aided by the DnaJ-like family of proteins, which interact with Hsp70s in order to enhance the chaperone activity of these proteins. DnaJ-like proteins contain a J domain, a seventy amino acid domain consisting of four α-helices, which is defined by the presence of an invariant tripeptide of histidine, proline and aspartic acid (HPD motif). This motif is key to the interaction between DnaJ-like proteins and Hsp70s. This thesis has focused on determining the presence of other conserved residues in the J domain and their role in mediating the interaction of DnaJ-like proteins with partner Hsp70s. DnaJ-like proteins from Agrobacterium tumefaciens RUOR were isolated and used as a model system. A. tumefaciens DnaJ (Agt DnaJ) was able to replace the lack of E. coli DnaJ in an E. coli null mutant strain, however, additional A. tumefaciens DnaJ-like proteins Agt DjC1/DjlA, Agt DjC2 and Agt DjC5 were unable to complement for the lack of E. coli DnaJ. Replacement of the Agt DnaJ J domain with J domains from these proteins resulted in non-functional chimeric proteins, despite some sequence conservation. The kinetics of the basal specific ATPase activity of Agt DnaK, and its ability to have this activity stimulated by Agt DnaJ and Agt DnaJ-H33Q were also investigated. Stimulation of the ATPase activity by Agt DnaJ ranged between 1.5 to 2 fold, but Agt DnaJ-H33Q was unable to stimulate the basal ATPase activity. Conserved amino acids in the J domain were identified in silico, and these residues were substituted in the J domain of Agt DnaJ. The ability of these derivative proteins to replace E. coli DnaJ was investigated. Alterations in the HPD motif gave rise to proteins unable to complement for lack of E. coli DnaJ, consistent with literature. Agt DnaJ-R26A was unable to replace E. coli DnaJ suggesting that Arg26 could be key to the interaction with partner Hsp70s. Agt DnaJ-D59A was unable to replace E. coli DnaJ; substitutions in Asp59 have not previously been shown to impact on the function of DnaJ. Substituting Arg63 in Agt DnaJ abrogated the levels of complementation. Substitution of several structural residues was also found to disrupt the in vivo function of Agt DnaJ suggesting that the maintenance of the structural integrity of the J domain was important for function. This study has identified a number of residues critical to the structure and function of the J domain of Agt DnaJ, and potentially of general importance as molecular determinants for DnaJ-Hsp70 interaction.
- Full Text:
- Date Issued: 2004
Algorithms for the solution of the quadratic programming problem
- Authors: Vankova, Martina
- Date: 2004
- Subjects: Quadratic programming , Nonlinear programming , Algorithms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11086 , http://hdl.handle.net/10948/348 , Quadratic programming , Nonlinear programming , Algorithms
- Description: The purpose of this dissertation was to provide a review of the theory of Optimization, in particular quadratic programming, and the algorithms suitable for solving both convex and non-convex quadratic programming problems. Optimization problems arise in a wide variety of fields and many can be effectively modeled with linear equations. However, there are problems for which linear models are not sufficient thus creating a need for non-linear systems. This dissertation includes a literature study of the formal theory necessary for understanding optimization and an investigation of the algorithms available for solving a special class of the non-linear programming problem, namely the quadratic programming problem. It was not the intention of this dissertation to discuss all possible algorithms for solving the quadratic programming problem, therefore certain algorithms for convex and non-convex quadratic programming problems were selected for a detailed discussion in the dissertation. Some of the algorithms were selected arbitrarily, because limited information was available comparing the efficiency of the various algorithms. Algorithms available for solving general non-linear programming problems were also included and briefly discussed as they can be used to solve quadratic programming problems. A number of algorithms were then selected for evaluation, depending on the frequency of use in practice and the availability of software implementing these algorithms. The evaluation included a theoretical and quantitative comparison of the algorithms. The quantitative results were analyzed and discussed and it was shown that the results supported the theoretical comparison. It was also shown that it is difficult to conclude that one algorithm is better than another as the efficiency of an algorithm greatly depends on the size of the problem, the complexity of an algorithm and many other implementation issues. Optimization problems arise continuously in a wide range of fields and thus create the need for effective methods of solving them. This dissertation provides the fundamental theory necessary for the understanding of optimization problems, with particular reference to quadratic programming problems and the algorithms that solve such problems. Keywords: Quadratic Programming, Quadratic Programming Algorithms, Optimization, Non-linear Programming, Convex, Non-convex.
- Full Text:
- Date Issued: 2004
- Authors: Vankova, Martina
- Date: 2004
- Subjects: Quadratic programming , Nonlinear programming , Algorithms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11086 , http://hdl.handle.net/10948/348 , Quadratic programming , Nonlinear programming , Algorithms
- Description: The purpose of this dissertation was to provide a review of the theory of Optimization, in particular quadratic programming, and the algorithms suitable for solving both convex and non-convex quadratic programming problems. Optimization problems arise in a wide variety of fields and many can be effectively modeled with linear equations. However, there are problems for which linear models are not sufficient thus creating a need for non-linear systems. This dissertation includes a literature study of the formal theory necessary for understanding optimization and an investigation of the algorithms available for solving a special class of the non-linear programming problem, namely the quadratic programming problem. It was not the intention of this dissertation to discuss all possible algorithms for solving the quadratic programming problem, therefore certain algorithms for convex and non-convex quadratic programming problems were selected for a detailed discussion in the dissertation. Some of the algorithms were selected arbitrarily, because limited information was available comparing the efficiency of the various algorithms. Algorithms available for solving general non-linear programming problems were also included and briefly discussed as they can be used to solve quadratic programming problems. A number of algorithms were then selected for evaluation, depending on the frequency of use in practice and the availability of software implementing these algorithms. The evaluation included a theoretical and quantitative comparison of the algorithms. The quantitative results were analyzed and discussed and it was shown that the results supported the theoretical comparison. It was also shown that it is difficult to conclude that one algorithm is better than another as the efficiency of an algorithm greatly depends on the size of the problem, the complexity of an algorithm and many other implementation issues. Optimization problems arise continuously in a wide range of fields and thus create the need for effective methods of solving them. This dissertation provides the fundamental theory necessary for the understanding of optimization problems, with particular reference to quadratic programming problems and the algorithms that solve such problems. Keywords: Quadratic Programming, Quadratic Programming Algorithms, Optimization, Non-linear Programming, Convex, Non-convex.
- Full Text:
- Date Issued: 2004
Rare earth element geochemistry of the Insizwa lobe of the Mount Ayliff Complex, Eastern Cape, South Africa
- Authors: Marsh, Julian S
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6736 , http://hdl.handle.net/10962/d1007548
- Description: New rare earth element (REE) data from all lithologies of the Insizwa lobe, Mount Ayliff Complex, are presented. On the basis of size and type of Eu anomaly, the geochemical subdivision of the complex as previously described is sustained and, additionally, the Top Gabbronorite of the Central Zone is shown to have formed from a magma that was compositionally distinct from other Central Zone magmas. The Basal Zone crystallized from magmas with large negative Eu anomalies probably acquired through crustal contamination. Previously recognized compositional heterogeneity in the contact rocks is also a feature of the REE. Overall, the Insizwa magmas had higher La/Sm ratios and, to a lesser extent, higher Gd/Yb ratios than Karoo basalts and appear to have no representatives in the basalt lava sequence of Lesotho.
- Full Text:
- Date Issued: 2004
- Authors: Marsh, Julian S
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6736 , http://hdl.handle.net/10962/d1007548
- Description: New rare earth element (REE) data from all lithologies of the Insizwa lobe, Mount Ayliff Complex, are presented. On the basis of size and type of Eu anomaly, the geochemical subdivision of the complex as previously described is sustained and, additionally, the Top Gabbronorite of the Central Zone is shown to have formed from a magma that was compositionally distinct from other Central Zone magmas. The Basal Zone crystallized from magmas with large negative Eu anomalies probably acquired through crustal contamination. Previously recognized compositional heterogeneity in the contact rocks is also a feature of the REE. Overall, the Insizwa magmas had higher La/Sm ratios and, to a lesser extent, higher Gd/Yb ratios than Karoo basalts and appear to have no representatives in the basalt lava sequence of Lesotho.
- Full Text:
- Date Issued: 2004
Language and value: towards accepting a richer linguistic ecology for South Africa
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7042 , http://hdl.handle.net/10962/d1007383 , https://doi.org/10.1075/lplp.28.2.05wri
- Description: preprint , Language policy debate is often obscured by two factors: failure to acknowledge different time-frames attending contrasting positions, and failure to recognise that ordinary people are motivated by their perceived best interests in the present. This article argues that the key to more general public acceptance of linguistic ecological diversity in South Africa is to shift the emphasis from policy development to practical language cultivation issues. Provide the requisite cultivation support, and acceptance of a revitalised future for African languages becomes more assured. It should also be understood that the modernisation of African languages in South Africa has a political dimension concerning which South African language commentators are strangely silent. This political thrust may not be entirely congruent with the concerns of those whose brief for African languages is primarily cultural or ecological – if, indeed, they are even aware of it. Finally, it needs to be recognised that language development under conditions of controlled influence, as in the civil service or schooling, is potentially achievable (with whatever difficulty), but that this must be complemented by authentic contemporary intellectual work published in African languages if the linguistic dimension of the African Renaissance is to take off.
- Full Text:
- Date Issued: 2004
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7042 , http://hdl.handle.net/10962/d1007383 , https://doi.org/10.1075/lplp.28.2.05wri
- Description: preprint , Language policy debate is often obscured by two factors: failure to acknowledge different time-frames attending contrasting positions, and failure to recognise that ordinary people are motivated by their perceived best interests in the present. This article argues that the key to more general public acceptance of linguistic ecological diversity in South Africa is to shift the emphasis from policy development to practical language cultivation issues. Provide the requisite cultivation support, and acceptance of a revitalised future for African languages becomes more assured. It should also be understood that the modernisation of African languages in South Africa has a political dimension concerning which South African language commentators are strangely silent. This political thrust may not be entirely congruent with the concerns of those whose brief for African languages is primarily cultural or ecological – if, indeed, they are even aware of it. Finally, it needs to be recognised that language development under conditions of controlled influence, as in the civil service or schooling, is potentially achievable (with whatever difficulty), but that this must be complemented by authentic contemporary intellectual work published in African languages if the linguistic dimension of the African Renaissance is to take off.
- Full Text:
- Date Issued: 2004
Shakespeare in South Africa: Alpha and ‘Omega’
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7029 , http://hdl.handle.net/10962/d1007216 , https://doi.org/10.1080/1368879042000210595
- Description: preprint , [Author's note]: This piece offers a discursive foray into some leading features of South African Shakespeare, framed between two symbolic ‘book-ends’: the first authenticated Shakespearean production which took place in Cape Town in 1801 (‘Alpha’), and a recent groundbreaking, multilingual version of Julius Caesar which premiered in 2001(“‘Omega’”). Focusing mainly on acts of translation, literal and cultural, the article follows a trajectory from colonial origins to explore some of the adaptive travail experienced by the Shakespeare text as it infiltrates, contests, melds into and sometimes illuminates a South African culture both potentially (and actually) very different from the colonial culture of, say, Australia or New Zealand. The article includes a brief prospectus for the future.
- Full Text:
- Date Issued: 2004
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7029 , http://hdl.handle.net/10962/d1007216 , https://doi.org/10.1080/1368879042000210595
- Description: preprint , [Author's note]: This piece offers a discursive foray into some leading features of South African Shakespeare, framed between two symbolic ‘book-ends’: the first authenticated Shakespearean production which took place in Cape Town in 1801 (‘Alpha’), and a recent groundbreaking, multilingual version of Julius Caesar which premiered in 2001(“‘Omega’”). Focusing mainly on acts of translation, literal and cultural, the article follows a trajectory from colonial origins to explore some of the adaptive travail experienced by the Shakespeare text as it infiltrates, contests, melds into and sometimes illuminates a South African culture both potentially (and actually) very different from the colonial culture of, say, Australia or New Zealand. The article includes a brief prospectus for the future.
- Full Text:
- Date Issued: 2004
The wing coupling apparatus and the morphometric analysis of honeybee populations
- Hepburn, H Randall, Radloff, Sarah E
- Authors: Hepburn, H Randall , Radloff, Sarah E
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6904 , http://hdl.handle.net/10962/d1011760
- Description: Significant differences between countries were found in the distribution of the number of hamuli within Apis andreniformis, A. florea, A. cerana and A. koschevnikovi. The mean hamuli numbers for Apis mellifera intermissa differed significantly among localities in Algeria. Significant differences in intercolonial variability between countries were found within A. cerana. There was no significant infraspecific variability within A. andreniformis, A. florea, A. koschevnikovi and A. m. intermissa. Significant differences in the mean number of hamuli occur between A. m. intermissa and A. andreniformis, A. florea and A. cerana; also between A. cerana/A. koschevnikovi and A. andreniformis and A. florea. Significant differences were found in the distribution and variability of the number of hamuli between species (populations). The mean numbers of hamuli for A. andreniformis differed from those of A. florea. Both these population means differed from those of A. cerana, A. koschevnikovi and A. m. intermissa. No significant differences were found between A. cerana and A. koschevnikovi. When the analysis included data for A. dorsata, A. nigrocincta, A. m. carnica, A. m. caucasica and A. m. ligustica, the results showed significant differences in hamuli numbers between A. andreniformis/A. florea and A. cerana/A. koschevnikovi/A. nigrocincta and A. m. intermissa/A. m. carnica/A. m. caucasica/A. m. ligustica. Hamuli numbers in A. dorsata significantly differed from those of other populations except A. m. intermissa. These results show that hamuli numbers are useful in the classification of honeybee populations. Whether hamuli would be useful in multivariate analysis depends on the correlation between the number of hamuli and the other characters used.
- Full Text:
- Date Issued: 2004
- Authors: Hepburn, H Randall , Radloff, Sarah E
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6904 , http://hdl.handle.net/10962/d1011760
- Description: Significant differences between countries were found in the distribution of the number of hamuli within Apis andreniformis, A. florea, A. cerana and A. koschevnikovi. The mean hamuli numbers for Apis mellifera intermissa differed significantly among localities in Algeria. Significant differences in intercolonial variability between countries were found within A. cerana. There was no significant infraspecific variability within A. andreniformis, A. florea, A. koschevnikovi and A. m. intermissa. Significant differences in the mean number of hamuli occur between A. m. intermissa and A. andreniformis, A. florea and A. cerana; also between A. cerana/A. koschevnikovi and A. andreniformis and A. florea. Significant differences were found in the distribution and variability of the number of hamuli between species (populations). The mean numbers of hamuli for A. andreniformis differed from those of A. florea. Both these population means differed from those of A. cerana, A. koschevnikovi and A. m. intermissa. No significant differences were found between A. cerana and A. koschevnikovi. When the analysis included data for A. dorsata, A. nigrocincta, A. m. carnica, A. m. caucasica and A. m. ligustica, the results showed significant differences in hamuli numbers between A. andreniformis/A. florea and A. cerana/A. koschevnikovi/A. nigrocincta and A. m. intermissa/A. m. carnica/A. m. caucasica/A. m. ligustica. Hamuli numbers in A. dorsata significantly differed from those of other populations except A. m. intermissa. These results show that hamuli numbers are useful in the classification of honeybee populations. Whether hamuli would be useful in multivariate analysis depends on the correlation between the number of hamuli and the other characters used.
- Full Text:
- Date Issued: 2004
A phenological and bioclimatic analysis of honey yield in South Africa
- Authors: Illgner, Peter Mark
- Date: 2004
- Subjects: Bee culture -- South Africa -- Statistics Honeybee -- South Africa Bee culture -- South Africa -- Management Honey plants -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5813 , http://hdl.handle.net/10962/d1007153
- Description: This study has investigated the interaction between honeybees and their forage plants and the impact of selected climatic variables on honey production in South Africa. Twenty-seven scale-hive records from 25 localities have been used as a measure of colony honey reserves. At least 944 plant species are visited by honeybees in South Africa for their nectar and/or pollen, with more than half providing both rewards. The entire honeybee flora encompasses 532 genera and 137 families. The flowering phenologies of the different reward categories of the indigenous forage plants are all significantly and positively correlated at the 0.05 level. Similarly, species offering both rewards are significantly and positively correlated with the flowering phenology of the null flora. The same results were obtained for correlations between the different reward categories of the exotic forage plants in South Africa. Of the 30 species pairs which fulfilled the criteria for selection, 23 occurred in sympatry, 5 in allopatry and 2 in possible parapatry. There is evidence for both competition and facilitation within different indigenous species pairs. The lack of geographical correlation in the intra-annual variation in honey stores and the near absence of any statistically significant (p < 0.05) honey related intra-annual intracolonial correlations may indicate that the former is more important than the latter for the determination of the level of honey reserves within a colony. Only one statistically significant correlation was found between either scale-hive record from the University of Pretoria Experimental Farm and any of the selected climatic variables. A one month lag period and/or possible seasonal effects were detected for each variable, with the exception of the duration of sunshine, in the autocorrelation analyses. A possible 12 month seasonal period was also identified in the single series fourier analyses for a number of variables. Similarly, 12 months was also the most frequently recurring period in the crossspectral results for the one scale-hive record (H42). Any activities which have an impact on the landscape have the potential to affect honeybees and/or their forage plants. Honeybee crop or plant pollination may also enhance yields for commercial farmers and facilitate rural food security.
- Full Text:
- Date Issued: 2004
- Authors: Illgner, Peter Mark
- Date: 2004
- Subjects: Bee culture -- South Africa -- Statistics Honeybee -- South Africa Bee culture -- South Africa -- Management Honey plants -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5813 , http://hdl.handle.net/10962/d1007153
- Description: This study has investigated the interaction between honeybees and their forage plants and the impact of selected climatic variables on honey production in South Africa. Twenty-seven scale-hive records from 25 localities have been used as a measure of colony honey reserves. At least 944 plant species are visited by honeybees in South Africa for their nectar and/or pollen, with more than half providing both rewards. The entire honeybee flora encompasses 532 genera and 137 families. The flowering phenologies of the different reward categories of the indigenous forage plants are all significantly and positively correlated at the 0.05 level. Similarly, species offering both rewards are significantly and positively correlated with the flowering phenology of the null flora. The same results were obtained for correlations between the different reward categories of the exotic forage plants in South Africa. Of the 30 species pairs which fulfilled the criteria for selection, 23 occurred in sympatry, 5 in allopatry and 2 in possible parapatry. There is evidence for both competition and facilitation within different indigenous species pairs. The lack of geographical correlation in the intra-annual variation in honey stores and the near absence of any statistically significant (p < 0.05) honey related intra-annual intracolonial correlations may indicate that the former is more important than the latter for the determination of the level of honey reserves within a colony. Only one statistically significant correlation was found between either scale-hive record from the University of Pretoria Experimental Farm and any of the selected climatic variables. A one month lag period and/or possible seasonal effects were detected for each variable, with the exception of the duration of sunshine, in the autocorrelation analyses. A possible 12 month seasonal period was also identified in the single series fourier analyses for a number of variables. Similarly, 12 months was also the most frequently recurring period in the crossspectral results for the one scale-hive record (H42). Any activities which have an impact on the landscape have the potential to affect honeybees and/or their forage plants. Honeybee crop or plant pollination may also enhance yields for commercial farmers and facilitate rural food security.
- Full Text:
- Date Issued: 2004
Changes in energy use patterns in the Bushbuckridge Lowveld of the Limpopo Province, South Africa: eleven years on
- Authors: Madubansi, Mainza
- Date: 2004
- Subjects: Energy consumption -- South Africa -- Limpopo
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4756 , http://hdl.handle.net/10962/d1007139 , Energy consumption -- South Africa -- Limpopo
- Description: This research reports on the energy transition that has taken place in the Bushbuckridge district between 1991 and 2002. It is a follow up to a similar study that was done in 1991 investigating a number of aspects of energy use. It uses the 1991 study as a baseline and aims to explore how the passage of time, growth of the local population and changes in incomes and the availability of fuels have affected the patterns of fuel use in the region in the past eleven years. A structured interview approach was used for most aspects of the study. The interview schedule included sections on types, amounts and reasons for use and non-use of 13 different energy sources as well as data on income levels, household size and other economic parameters. Analysis of the consumption patterns of the different fuel types revealed that between the two survey periods, households in the sample settlements went through some pronounced changes in patterns of fuel use, particularly those that had acquired electricity. The introduction of electricity in the region had certainly played a major role in spurring the energy transition. Fuels that were previously used for lighting, powering entertainment appliances and refrigeration had been displaced by electricity. In terms of cooking and other thermal application, however, the vast majority of households in all the sample settlements continued using fuelwood and complemented it to a lesser extent with paraffin and electricity. In both surveys, the use or non-use of available fuels in the region was influenced by several factors. Common reasons for non-use of certain fuel types included expense, lack of appliances, the risk involved in using such fuels and the preference for other fuels. Reasons for use were mainly related to the low cost of the fuel and the fuel’s ability to meet particular end uses. Although incomes in the region had increased between 1991 and 2002, they were still below the poverty line. Activities from which households obtained their income remained the same. Old age pension, migrant wages and the informal sector remained the largest contributors of income to most households. Other indicators of relative wealth and poverty, like ownership of vehicles, bicycles and beds remained the same.
- Full Text:
- Date Issued: 2004
- Authors: Madubansi, Mainza
- Date: 2004
- Subjects: Energy consumption -- South Africa -- Limpopo
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4756 , http://hdl.handle.net/10962/d1007139 , Energy consumption -- South Africa -- Limpopo
- Description: This research reports on the energy transition that has taken place in the Bushbuckridge district between 1991 and 2002. It is a follow up to a similar study that was done in 1991 investigating a number of aspects of energy use. It uses the 1991 study as a baseline and aims to explore how the passage of time, growth of the local population and changes in incomes and the availability of fuels have affected the patterns of fuel use in the region in the past eleven years. A structured interview approach was used for most aspects of the study. The interview schedule included sections on types, amounts and reasons for use and non-use of 13 different energy sources as well as data on income levels, household size and other economic parameters. Analysis of the consumption patterns of the different fuel types revealed that between the two survey periods, households in the sample settlements went through some pronounced changes in patterns of fuel use, particularly those that had acquired electricity. The introduction of electricity in the region had certainly played a major role in spurring the energy transition. Fuels that were previously used for lighting, powering entertainment appliances and refrigeration had been displaced by electricity. In terms of cooking and other thermal application, however, the vast majority of households in all the sample settlements continued using fuelwood and complemented it to a lesser extent with paraffin and electricity. In both surveys, the use or non-use of available fuels in the region was influenced by several factors. Common reasons for non-use of certain fuel types included expense, lack of appliances, the risk involved in using such fuels and the preference for other fuels. Reasons for use were mainly related to the low cost of the fuel and the fuel’s ability to meet particular end uses. Although incomes in the region had increased between 1991 and 2002, they were still below the poverty line. Activities from which households obtained their income remained the same. Old age pension, migrant wages and the informal sector remained the largest contributors of income to most households. Other indicators of relative wealth and poverty, like ownership of vehicles, bicycles and beds remained the same.
- Full Text:
- Date Issued: 2004
An investigation into the antibacterial activites of medicinal plants traditionally used in the Eastern Cape to treat lung infections in cystic fibrosis patients
- Authors: Wilson, Katherine Leigh
- Date: 2004
- Subjects: Medicinal plants -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10985 , http://hdl.handle.net/10948/242 , Medicinal plants -- South Africa -- Eastern Cape
- Description: Lung infections in cystic fibrosis (CF) patients are very serious and are usually fatal. Prolonged antibiotic treatment can result in the development of antibiotic resistance. Thus, studies are required to determine if traditional medicinal plants have any significant effects (i.e. antibacterial effects in this case) on certain bacteria causing lung infections in CF patients, providing possible alternative treatment. The aim of this study was to test the effects of several Eastern Cape medicinal plants on specific bacteria causing lung infections in CF patients, for possible antibacterial activities. Four plants traditionally used to treat lung infections (Artemisia afra, Dodonaea angustifolia, Leonotis leonurus & Tulbaghia violacea), and different strains of four bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Pseudomonas species & Klebsiella pneumoniae), usually causing lung infections were investigated. Methanol, aqueous and acetone extraction methods were used to make extracts of the various plants chosen. A decoction of each plant was also investigated. An adapted microtitre plate method for testing the antibacterial activity of the plant extracts against the chosen bacteria was used. The minimum inhibitory concentration (MIC) of each plant extract was determined by means of this method.
- Full Text:
- Date Issued: 2004
- Authors: Wilson, Katherine Leigh
- Date: 2004
- Subjects: Medicinal plants -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10985 , http://hdl.handle.net/10948/242 , Medicinal plants -- South Africa -- Eastern Cape
- Description: Lung infections in cystic fibrosis (CF) patients are very serious and are usually fatal. Prolonged antibiotic treatment can result in the development of antibiotic resistance. Thus, studies are required to determine if traditional medicinal plants have any significant effects (i.e. antibacterial effects in this case) on certain bacteria causing lung infections in CF patients, providing possible alternative treatment. The aim of this study was to test the effects of several Eastern Cape medicinal plants on specific bacteria causing lung infections in CF patients, for possible antibacterial activities. Four plants traditionally used to treat lung infections (Artemisia afra, Dodonaea angustifolia, Leonotis leonurus & Tulbaghia violacea), and different strains of four bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Pseudomonas species & Klebsiella pneumoniae), usually causing lung infections were investigated. Methanol, aqueous and acetone extraction methods were used to make extracts of the various plants chosen. A decoction of each plant was also investigated. An adapted microtitre plate method for testing the antibacterial activity of the plant extracts against the chosen bacteria was used. The minimum inhibitory concentration (MIC) of each plant extract was determined by means of this method.
- Full Text:
- Date Issued: 2004