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Understanding how teachers scaffold learners to make sense of biological language and concepts when using English as a mediational tool: a case study

  • Authors: Nakale, Elifas
  • Date: 2013
  • Subjects: Biology -- Study and teaching (Secondary) -- Namibia Language and education -- Namibia , English as medium of instruction
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1386 , http://hdl.handle.net/10962/d1001517
  • Description: For the past few years, Namibian grade 11-12 learners’ achievement level in biology has not been very encouraging. Evidence to this effect is contained in recent examiners’ reports which outline misunderstanding and various misconceptions. The causes of these misunderstandings and misconceptions may be varied, but there is credible evidence that some of it is rooted in the language problem for learners. A classroom is a social unit where many social practices are acquired, including the use of English language. Equally, it is a place where errors in language are learnt and reinforced. Triggered by these challenges facing biology learners, a qualitative case study was conducted at two secondary schools in Ohangwena Region, Namibia. Its purpose was to investigate how biology teachers scaffold learners to make sense of biological language and concepts when English is used as the mediational tool. Underpinned by an interpretivist paradigm, the study made use of document analysis, observation (lessons were also video-taped) and interviews to generate the data. Several data generating techniques were used for triangulation and validation. To further validate the data, transcripts of video-taped lessons and interviews were sent back to the research participants for member checking. The data gathering methods were also used in data presentation, analysis and interpretation to determine the extent of scaffold that teachers provide to their biology learners. The main findings of my study are that, despite efforts by participant teachers to scaffold their learners in making sense of biological language and concepts, success rates in this regard remain disappointingly low due to their (teachers) limited pedagogical content knowledge. Teachers therefore require improved mentorship, monitoring and capacity building.
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Pre-concentration of heavy metals in aqueous environments using electrospun polymer nanofiber sorbents

  • Authors: Darko, Godfred
  • Date: 2012
  • Subjects: Heavy metals -- Absorption and adsorption -- Research Nanochemistry -- Research Polystyrene -- Research Polyamides -- Research
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4337 , http://hdl.handle.net/10962/d1004998
  • Description: This thesis presents an alternative approach for pre-concentrating heavy metals in aqueous environments using electro spun polymer nanofiber sorbents. The conditions for electrospinning polyethersulfone, polystyrene, polysulfone and polyamide-6 were optimized. The morphologies and porosities of the electrospun nanofibers were studied using SEM and BET nitrogen gas adsorptions. The nanofibers had mesoporous morphologies with specific surface areas up to 58 m2/g. The electro spun nanofiber sorbents were characterized in terms of their tunability for both uptake and release of heavy metals. The usability of the sorbent was also assessed. The sorbents showed fast adsorption kinetics for heavy metals « 20 min for As, Cu, Ni and Pb) in different aqueous environments. The adsorption characteristics of the sorbents best fitted the Freundlich isotherm and followed the first order kinetics. The efficiencies of adsorption and desorption of heavy metals on both imidazolyl-functionalized polystyrene and amino-functionalized polysulfone sorbents were more than 95% up to the fifth cycle of usage. Reusability improved dramatically (up to 10 runs of usage) when mechanically stable amino-functionalized nylon-6 electro spun nanofibers were used. The capacity of the amino-functionalized nylon-6 sorbent to pre-concentrate heavy metals compared very favourably with those of aqua regia and HN03+H202 digestions especially in less complex matrices. Due to their highly porous nature, the electro spun nanofibers exhibited high adsorption capacities (up to 50 mg/g) for heavy metal ions. The loading capacities achieved with the imidazolyl-functionalized sorbent were higher than those for amino-functionalized mesoporous silica and biomass-based sorbents. The electro spun nanofiber sorbents presents an efficient and cost effective alternative for preconcentrating heavy metals in aqueous environments.
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The isolation, quantification and synthetic modification of antiplasmodial natural products from sargassum heterophyllum

  • Authors: Munedzimwe, Tatenda Carol
  • Date: 2012
  • Subjects: Malaria -- Developing countries -- Prevention , Antimalarials
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:3871 , http://hdl.handle.net/10962/d1018252
  • Description: Malaria is one of the most deadly parasitic diseases known to man. Although the number of malaria cases reported each year is decreasing, this disease continues to pose health and economic problems mainly in developing countries. Significant progress has been made in the fight against this disease. This includes the discovery and development of potent antimalarial agents. However, the development of resistance to most of these potent antimalarials has made the development of new antiplasmodial agents of paramount importance. Several promising antiplasmodial agents have been found from the marine environment. Amongst these are the tetraprenylated toluquinols from the brown alga: Sargassum heterophyllum. These metabolites have been reported to exhibit a range of antiplasmodial activity; however, the mechanisms by which these compounds bring about their antiplasmodial activity and the pharmacophoric groups responsible for such activity are unknown. Two species of Sargassum algae were encountered during the course of this project. From the investigation of the geographical and seasonal variation of metabolites of S. heterophyllum and S. elegans we established that there were no significant intra and inter site variations amongst metabolite profiles of both species both within and between the sampled seasons. These results enabled us to establish that the collection of both species from three different sites on the eastern coast of South Africa namely; Kenton on Sea, Port Alfred and Noordhoek in autumn, winter or spring would qualitatively yield the same metabolites. A comparison of metabolite profiles of both species also revealed no qualitative differences between metabolites of S. heterophyllum and S. elegans. The quantities of selected prenylated metabolites extracted from S. heterophyllum using four different extraction techniques was also assessed using qNMR as the method of quantification. This led to the identification of optimal extraction techniques and conditions for the extraction of sargahydroquinoic acid (1.38), sargaquinoic aid (1.39) and sargachromenol (2.10) from S. heterophyllum. From this study, the extraction of algae by soxhlet extraction using EtOH as the extraction solvent led to the extraction of the highest quantities of sargahydroquinoic acid. The potential of other extraction techniques such as microwave assisted extraction, to yield high quantities of the selected metabolites were also identified. With gram quantities of sargahydroquinoic acid (1.38) in hand, this compound was modified by oxidation, reduction, acetylation, methylation and cyclization reactions to yield nine derivatives. The derivatives and four naturally occurring prenylated toluquinols were assessed for antiplasmodial and cytotoxic activity against the FCR-3 Gambian Chloroquine resistant strain of P. falciparum and the MDA-MB-231 breast carcinoma cell line respectively. Comparison of antiplasmodial data for all twelve compounds showed that the hydroquinone moeity of sargahydroquinoic acid (1.38) is important for antiplasmodial activity while esterification of the carboxylic acid group in 1.38 resulted in more potent antiplasmodial compounds. Of all twelve compounds, compound 5.2, the hydroquinone methyl ester of 1.38 was found to be the most potent antiplasmodial compound with an IC₅₀ value of 1.94 μM and a selectivity index of 22.68.
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The justice of Dikê on the forms and significance of dispute settlement by arbitration in the Iliad

  • Authors: Malamis, Daniel Scott Christos
  • Date: 2011
  • Subjects: Homer. Iliad Epic poetry, Greek -- History and criticism Law in literature Justice in literature Dispute resolution (Law) Arbitration and award (Greek law)
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3587 , http://hdl.handle.net/10962/d1002162
  • Description: This thesis explores the forms and significance of dispute settlement by arbitration, or ‘δίκη’, in the Iliad. I take as my focus the ‘storm simile’ of Iliad XVI: 384-393, which describes Zeus’ theodical reaction to corruption within the δίκη-court, and the ‘shield trial’ of Iliad XVIII: 498-508, which presents a detailed picture of such a court in action, and compare the forms and conception of arbitration that emerge from these two ecphrastic passages with those found in the narrative body of the poem. Analysing the terminology and procedures associated with dispute settlement in the Iliad, I explore the evidence for the development of an ‘ideology of δίκη’, that valorises arbitrated settlement as a solution to conflict, and that identifies δίκη as a procedure and a civic institution with an objective standard of fairness: the foundation of a civic concept of ‘justice’. I argue that this ideology is fully articulated in the storm simile and the shield trial, as well as Hesiod’s Works and Days, but that it is also detectable in the narrative body of the Iliad. I further argue that the poet of the Iliad employs references to this ideology, through the narrative media of speech and ecphrasis, to prompt and direct his audience’s evaluation of the nature and outcome of the poem’s central conflict: the dispute of Achilles and Agamemnon.
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A case study of teacher modification strategies in an ESL classroom context

  • Authors: Rataza, Themba Theophilus
  • Date: 2006
  • Subjects: English language -- Study and teaching (Foreign speakers) -- South Africa -- Eastern Cape English language -- Study and teaching (Secondary) -- South Africa -- Eastern Cape Code switching (Linguistics) -- South Africa Language and education -- South Africa
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1925 , http://hdl.handle.net/10962/d1007558
  • Description: The purpose of this study is to explore and discuss the use of teacher modification strategies by a high school teacher in the Eastern Cape province of South Africa in an English second language classroom. This teacher does not share the mother tongue of the learners. Unlike other teachers who resort to code switching when teaching L2 learners, this particular educator does not have that liberty. Code switching has been found to be a useful strategy for teaching and learning (Adendorff 1996, Marawu 1996). Code switching will henceforth be abbreviated as CS in the rest of the text. Often teachers use CS to help students understand as an avoidance strategy to teach in English. They have no other way of getting through to students because they haven't been shown the benefits of teacher modification strategies employed by the teacher I have observed in this study. The study therefore seeks to establish or investigate and describe the modification strategies the teacher uses to make his lessons comprehensible to his learners and to accommodate the needs of his L2 learners in view of the fact that he does not share the language of his learners. The motivation behind this study stems from the difficulties experienced by L2/ESL learners learning through the medium of English. These problems are described by researchers such as Macdonald (1990), Eiseman (1992), NEPI report (1992). These difficulties relate to the lack of vocabulary, low proficiency levels and comprehension skills. In view of the above, this case study research was conducted on one teacher to find out or investigate how he modifies his teaching strategies. It has been revealed in the literature studied / reviewed that teachers employ a variety of teaching strategies to adapt to the needs of their L2 learners. (Long (1983), Wong-Filhnore (1985), Chaudron (1988), Huizenga et al (1990)). The teacher in this study has also been found to employ the main strategies to modify his teaching practice. It is clear from the interviews with both the teacher and his students, that this particular teacher makes full use of a range of language and methodological strategies to help his students understand his lessons. It is hoped that the findings of this research may illuminate some valuable insights in the necessity and usefulness of teacher modification strategies for all teacher trainers so that our teaching institutions can provide a variety of methods for teacher trainees to help L2 students develop their English language skills.
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Towards more accurate measurement of the value of the arts to society: economic impact and willingness to pay studies at the Standard Bank National Arts Festival

  • Authors: Snowball, Jeanette Dalziel
  • Date: 2001
  • Subjects: Standard Bank National Arts Festival , Standard Bank National Arts Festival -- Economic aspects , Art -- Economic aspects , Money in art , Art -- Marketing , Performing arts festivals -- Economic aspects -- South Africa -- Grahamstown
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:939 , http://hdl.handle.net/10962/d1002672
  • Description: The accurate measurement of the value of the arts to society is becoming increasingly important in developing countries, like South Africa, where the arts must compete with housing, health, education and the like for public funds. Motivation for the public funding of arts events, like the Standard Bank National Arts Festival in Grahamstown, is usually based on the economic impact, that is, the financial benefits to the region, of such events. The argument is problematic, however, because the primary recipients of such economic benefits are often middle to upper income groups who also attend more arts performances. Furthermore, the studies have not taken into account the positive externalities which, it is argued, are generated by the arts and are enjoyed by attenders and non attenders alike. This thesis argues that it is the social benefits which the arts provide, those external to the market, which should be the basis of public funding. In order to quantify these positive externalities, a willingness to pay (WTP) study was conducted in the Grahamstown region. It is generally, but erroneously, believed that the Festival does not benefit the poorer, largely black, Grahamstown East residents. The study found that, in addition to the economic value (R23 - 25 million a year), the non-market benefits which the festival provides are worth between R2.3 and R3 million a year and form a very important part of its value, particularly to low income groups. The study also found that there are methodological adjustments which can be made to WTP studies to successfully control for the many forms of bias it is prone to. By using a combination of closed and open ended and liable and non-liable questions, the motivation of respondents' answers to WTP questions was determined, making it possible to adjust for bias caused by, for example, "free rider" and "warm glow" responses. It is argued that by identifying and excluding such responses from WTP surveys, it is possible to reduce bias to an acceptable level.
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Insect herbivores associated with Senecio pterophorus and Senecio inaequidens at Butterworth, South Africa

  • Authors: Muwanga-Zake, Johnnie Wycliffe Frank
  • Date: 1995
  • Subjects: Senecio -- South Africa -- Eastern Cape -- Butterworth Insect-plant relationships -- South Africa -- Eastern Cape -- Butterworth Insects -- South Africa -- Eastern Cape -- Butterworth -- Host plants Insects -- South Africa -- Eastern Cape -- Butterworth -- Food Lixus -- biology Insect-plant relationships
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5716 , http://hdl.handle.net/10962/d1005402
  • Description: This study lists and compares insect herbivores of Senecio inaequidens and of Senecio pterophorus around Butterworth by 18 Tables and 38 Figures. The two plant species are widely distributed around Southern Africa. Samples were taken during a month of each of the four main seasons of the year, which in Butterworth did not show much difference in temperature. The two plant species shared generalist insect herbivores most of which were also on other surrounding plant species. The population of most of the herbivores was affected by the seasons while the two plant species were not seasonal, thus the correlation between insect herbivores and the two plant species was not significant. The heavier, and apparently chemically protected species, Senecio pterophorus, accommodated borers and supported a wider variety of but fewer individual insects. Senecio pterophorus could be having more defences but had more serious herbivores. There were no serious insect herbivores that could control the abundance of the two plant species around Butterworth. Anatomical differences between S. pterophorus and S. inaequidens could be highlighted by the kind and number of insect herbivores found upon them. Similarities were more difficult to identify through studying their insect herbivores. The biology of one serious weed, Lixus sp., on Senecio pterophorus was studied in more detail. The life cycle of the weevil was found to be synchronised with that of the host. This weevil shared the stems with other species of weevils with no indication of competition.
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The representation of women in the plays of Sam Shepard

  • Authors: Volks, Carolyn Dana
  • Date: 1994
  • Subjects: Shepard, Sam, 1943- -- Characters -- Women , Shepard, Sam, 1943- -- Criticism and interpretation
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2151 , http://hdl.handle.net/10962/d1002383 , Shepard, Sam, 1943- -- Characters -- Women , Shepard, Sam, 1943- -- Criticism and interpretation
  • Description: In the endeavour to abolish from society all forms of ideologies that prescribe the domination of one sex over another, it has become increasingly important to analyse the representation of women in dramatic literature because dramatic literature reflects the philosophies and codes of behaviour which enable individuals to dominate one another in society, and assists in either reinforcing old ideologies or shaping new ones. Although Sam Shepard has been an influential force in the creation of modern drama, his plays reflect a patriarchal ideology that dictates that women are subordinate to men. Shepard's plays dramatise various male predicaments and his female characters are constructed and utilised to express men's experience, not women's. One of the conflicts which besets the male characters is that they desire to return to the womb of the mother, but simultaneously fear that their identities will be engulfed by the mother. In The Rock Garden, Red Cross and Fourteen Hundred Thousand, these desires and fears are demonstrated through the female characters, who are manipulated to represent objects of male desire and/or objects onto which devouring images are projected. Women are therefore represented in a manner in which they are best able to express the male characters' identity related conflicts. In Curse of the Starving Class and Buried Child, characters suffer from receiving insufficient nurture, are spiritually and emotionally impoverished or cursed and appear unable to transform their lives. The female characters are presented as being partly responsible for causing these predicaments since their nurturing, generative and transformative abilities are presented in a negative light. Women are also represented as objects of blame in the male characters' attempts and failures to undergo rebirths and are once again created to express male predicaments. In Fool for Love and A Lie of the Mind, Shepard focuses on the relationships between men and women, but is only able to present the male characters' perspectives and represent male desire. The female characters are regarded, and engaged with, as reflections of the male characters' selves and are frequently utilised to express male desire. If Shepard's plays are persistently applauded and seen as examples to be emulated, we need to closely analyse these dramas that represent women in a manner which expresses male predicaments and which places them in roles that allow men to dominate them.
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Towards the development of an environmental curriculum for members of the planning professions

  • Authors: Long, Stanford Staples
  • Date: 1994
  • Subjects: Ecology -- Policy Education -- Environmental aspects Curriculum planning -- South Africa
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1802 , http://hdl.handle.net/10962/d1003687
  • Description: In exercising their professional duties professional planners inevitably impact on the environment. In the past, more often than not, this impact has been allowed to occur without sufficient forethought, and usually to the detriment of the environment. In this research it is proposed that this undesirable state of affairs arises from inadequacies within the professional education of the planners, and that greater emphasis on the environmental education of planners is called for. From the perspective of a participative approach to curriculum development, the opinions of professional planners in the Port Elizabeth area were canvassed to establish baseline data in respect of their environmental education needs. To provide further information and a background against which the perceptions of the professional planners could be assessed, the opinions of the learned societies of the planning professions and of key environmentalists were also sought. In all these opinion surveys postal questionnaires formed the basis of the methodology employed. The extent of environmental education presently available to professional planners at tertiary institutions in South Africa and overseas, with particular emphasis on that available in the civil engineering discipline, was also investigated. The surveys revealed a strongly felt need for environmental education within the planning professions. The natural environment, the social environment, environmental ethics and interdisciplinary action all emerged as acceptable themes of the said education. A number of environmental topics to be covered were also identified. Block-release and part-time courses emerged as the most popular format for such environmental education offerings. The limited environmental education practice within the civil engineering discipline at South African tertiary institutions was noted, and the overseas practice in this regard provided useful insights. The data gathered as outlined above, formed the basis from which proposals towards an environmental curriculum for professional planners were made. Although these proposals focused primarily on the civil engineering discipline within the ambit of technikon-based educational programmes, wider multi-disciplinary applications remained an important concern. In the first instance, proposals aimed at expanding the environmental component of the existing first-qualification course were suggested. Secondly, proposals in respect of a post-first qualification, interdisciplinary, environmental study programme leading to a technikon degree were formulated.
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Plastic changes in spinal function of pre-pubescent scoliotic children engaged in an exercise therapy programme

  • Authors: Solberg, Gill
  • Date: 1993
  • Subjects: Exercise therapy -- Methods , Scoliosis in children -- Exercise therapy -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:5163 , http://hdl.handle.net/10962/d1015973
  • Description: Previous studies of the effect of exercise therapy on scoliosis have demonstrated progression of spinal curves despite vigorous exercise regimens. This study presents evidence to the contrary. Ten children with functional scoliosis and attendant upper thoracic asymmetries were analyzed both before and after a specific exercise therapy programme, in order to determine the effect of the therapy on spinal functionality and the scoliotic curve. The effect of this intensive treatment, in which the subjects underwent a five-month exercise training programme with a total of 60 one-hour sessions, was investigated in a controlled clinical trial. A subjective and objective appraisal of posterior trunk asymmetry in schoolchildren aged 7-18 is reported. Selected functional and anthropometric measurements were made before and after the treatment, and antero-posterior x-rays were used to indicate changes in the scoliotic curve. New methods are described for quantifying the scoliotic curves in each child. Post-treatment tests showed a significant (p<0.05) decrease in Cobb's angles as well as a significant reduction in all the spinal and thoracic functional asymmetries observed in the study. The findings suggest that selective exercise programmes can contribute to improvement in cases of functional scoliosis. The study sheds new light on problems related to scoliosis and the benefits of exercise rehabilitation. Data on the incidence of scoliosis amongst 1052 black children are also presented and discussed.
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Pilot study for a language experience project across the curriculum at the Cape College of Education

  • Authors: Van Zyl, Alfred Edward
  • Date: 1986
  • Subjects: Curriculum planning Teachers -- Training of Language and education -- South Africa
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1832 , http://hdl.handle.net/10962/d1003914
  • Description: From Introduction: The intention of this thesis is not the legitimising of a language across the curriculum project, but will rather attempt to illustrate that a language experience project across the curriculum is essential at the Cape College of Education. The Cape College of Education is currently the only black teacher training college in the Cape Province. This young college, which opened in 1981, is situated on the outskirts of Fort Beaufort and fills the vacuum left by the closure of Lovedale College. Students are drawn from the black population of the Cape Province, which is almost exclusively Xhosa-speaking. There is an equal mixture of male and female students and a similar number of students from both rural and urban environments. The ages of 1st-year students range from 18 years to 44 years, with a predominance of 25 - 27 year olds. All students are in full residence. The College offers 3-year courses leading to diplomas in Primary and Secondary school teaching. In the ensuing sections an attempt will be made to show why a language across the curriculum (LAC) project is recommended for the Cape College of Education and what form it should take. However, as a 'cross curriculum' project has never been officially attempted amongst the Xhosa, very little 'proven' material and empirical evidence exists. Consequently, this discourse may at times appear to lean rather heavily on the support of 'what has happened in England'. To overcome this shortcoming, the opinions of the English Language Teaching Centre (ELTIC), which consists of a number of very active and involved black, English teachers, was consulted. The paper delivered by this group of teachers at the 1982 Conference of the Institute of English in Africa, in Grahamstown, provides much support for the arguments presented in this thesis. Extensive use has been made of it to reveal the nature of the situation against which the language department at the Cape College of Education (henceforth referred to as CCE) is attempting to successfully teach English to students who are aspiring to eventually teach through the medium of English themselves. Copious use of quotations has been made in this presentation in an attempt to support many of the 'unmeasurable' arguments presented. This has been necessary as very little substantiated data relating to the matters under discussion exist at this stage. For example, "The claim that exposure to literature enhances English language competence has not, to our knowledge, been tested, nor have the categories of a new linguistic knowledge been defined." (Institute of English in Africa Paper, 1982)
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Evaluation of Tucumania Tapiacola Dyar (Lepidoptera: Phycitidae) for biological control of jointed cactus in South Africa

  • Authors: Hoffmann, John Hugh
  • Date: 1982
  • Subjects: Phycitidae Cactus -- South Africa Weeds -- Biological control -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5634 , http://hdl.handle.net/10962/d1005316
  • Description: Jointed cactus, 0puntia aurantiaca Lindley, remains a problem and continues to expand its range in South Africa, in spite of a mandatory herbicidal control. programme. The feasibility of biologically controlling the weed is being explored because the cost of herbicides has escalated and, if it succeeds, biological control is permanent self perpetuating and relatively cheap. This thesis describes the introduction and release in South Africa of the phycitid moth, Tucumania tapiacola Dyar, as a potential biocontrol agent against jointed cactus. A preliminary objective of the study was to resolve the taxonomic confusion within the genus Tucumania, so that the various populations of the moth from widespread localities and from different host plants could be identified. The efficiency of mass-producing T. tapiacola in the insectary was continually improved through investigations of the insects biology, and its response to various environmental parameters. Techniques were developed to manipulate the different life-stages of T. tapiacola so that every release was made with the maximum possible number of individuals, all in the same stage of development. Trials were made with various methods for transporting and releasing T. tapiacola in the field, and the most successful of these were employed during the establishment programme. In all, approximately 830 000 T. tapiacola eggs, larvae and adults have been released at seven localities in South Africa, between May 1977 and February 1982. So far, the moth has failed to establish for more than three to five generations at any release site, for reasons that were not immediately apparent. The mortality factors acting against the immature stages of T. tapiacola have been investigated and quantified. The accumulated data were used to construct partial-life-tables and survivorship curves. These show that survival of the eggs, larvae and pupae differed in shaded and exposed habitats, and on small, medium and large O. aurantiaca plants. The overall mortality suffered by the immature stages alone did not account for the establishment failure. Alternatively, genetic problems that are commonly associated with the collection, mass production and release of biocontrol agents may have been responsible for the failure. Methods of overcoming these problems during future releases are discussed.
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Synthesis and reactions of sugar chlorosulphates

  • Authors: Glass, Beverley Dawn
  • Date: 1982
  • Subjects: Chemical reactions Sugar -- Synthesis
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:3826 , http://hdl.handle.net/10962/d1006145
  • Description: Summary: Partially chlorosulphated derivatives were synthesised for the purpose of examining the reactions of the chlorosulphonyloxy group in the presence of free hydroxyl groups. The behaviour of the chlorosulphonyloxy group was investigated under acidic conditions. Since sterically favoured chlorosulphonyloxy groups undergo facile replacement by chlorine to form chlorodeoxy sugars, some compounds possessing chlorosulphonyloxy groups which,due to polar and steric effects are not replaced by chloride,were investigated with a view to possible activation of the unfavourable centres towards nucleophilic substitution, thereby making available previously inaccessible chlorodeoxy sugars.
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The church music of Felix Mendelssohn-Bartholdy :|ban investigation into formal and stylistic aspects of his organ and sacred choral works

An examination of the spatial variation of surficial sediment characteristics in the Howison's Poort Reservoir

  • Authors: Weaver, Alex van Breda
  • Date: 1979
  • Subjects: Howison's Poort Reservoir , South Africa , Sedimentation and deposition
  • Language: English
  • Type: text , Thesis , Masters , MA
  • Identifier: vital:4790 , http://hdl.handle.net/10962/d1001890
  • Description: From Introduction: Lakes, estuaries and man-made water impoundments can be considered as intervening basins which provide for the temporary storage both of sediment and of water. Because of the potential energy of soil in elevated positions and because of the kinetic energy of water flowing under the influence of gravity, eroded material is eventually transported to the lowest possible level, i.e. the ocean deeps, or some intervening basin. This denudation process may be compared with Newton’s second law of thermodynamics which states that each system tends to move in the direction of lowest energy. Sedimentation in intervening basins may be seen as part of the natural process of landscape evolution. The rates at which sedimentation occurs may be strongly influenced by the activities of man.
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A study of South African aquatic Hyphomycetes

  • Authors: Greathead, Sarah Kathleen
  • Date: 1962
  • Subjects: Hyphomycetes -- South Africa , Aquatic fungi -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4269 , http://hdl.handle.net/10962/d1014992
  • Description: 1, Eighteen species of aquatic Hyphomycetes are recorded from South Africa for the first time. All except two of these can be assigned to described species. The other two are new species of Articulospora and Anguillospora and are described in this thesis. Three unidentified spore types, an "Articulospora" type and "Anguillospora" type and a Y-shaped spore are also described. 2. Spore development in ten species is described. 3. A key to the fungi described in this thesis is given. 4. General notes on the ecology of these fungi and a table recording the fungi found in the Eastern Cape Province of South Africa, their distribution within the localities and the nature of the material on which they are growing are given. 5. The gross characteristics of plate cultures of six species, five growing on malt agar, Czapek agar, plain agar and maize agar and one on malt agar only are described. 6. Growth of four species in liquid culture using the Czapek-Dox medium is reported. 7. The results of an investigation into the effect of variations in temperature and medium on the growth of plate cultures of five species are analysed, discussed and conclusions are drawn. 8. Growth of certain isolates of four species on twigs is described.
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