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The interactive effects of light, temperature and CO₂/O₂ ratios in photosynthesis of Coix lachryma-jobi L

  • Authors: Mjwara, Jabulani Michael
  • Date: 1992
  • Subjects: Coix , Plants -- Effect of light on , Plants -- Effect of oxygen on , Plants -- Effect of carbon dioxide on , Photosynthesis , Plants -- Effect of temperature on
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4216 , http://hdl.handle.net/10962/d1003785
  • Description: A portable infra red gas analyzer was used to investigate the interactive effects of light, temperature, and CO,jO, ratios under controlled environmental conditions in an attempt to model gas exchange characteristics of Coix Iachryma-jobi L. Plotting light response curves as a function of temperature (20, 25 30 and 35°C) revealed no sign of light saturation even at a photosynthetic photon flux density (PPFD) close to 2000 !Lmol m-' sol. High net assimilation rates (A) of approximately 24 !Lmol CO, m"s'! were realized at 30-35°C. Assimilation (A) versus internal CO, partial pressure (C,) curves showed a steep rise with increase in C, but saturated at approximately 150 (JLII-!) and all the results, either in the absence or presence of 0" showed a similar response under all temperature regimes. C. Iachryma-jobi exhibited low CO, compensation points cr ) between 0 and 10 JLlI-! under similar experimental temperatures and either at 0 or 21%0,. The slopes of double reciprocal plots of llA versus llCi, were nearly identical and crossed the yintercept at almost identical points under all 0, concentrations. These data indicate first; that there was no apparent 0, inhibition and second; indicated that the apparent inhIbitor constant (K,) for 0, at the site of carboxylation did not change with increase in [OJ from 0 to 21% oxygen. These observations were further confirmed by results obtained from the analysis of apparent carboxylation efficiency (CE, as defined as the slope of response of A to increasing CO,), as no inhibition of A with increase of [OJ occurred. These characteristics were consistent with typical features of C,photosynthesis. The absence of 0, inhibition and low r values indicated that an efficient CO, concentrating mechanism which eliminates photorespiration exists in C. Iachryma-jobi. At the light microscope level, leaf anatomy exhibited typical C, structure viz. bundle sheath with large chloroplasts and this sheath is further surrounded by a radiate Kranz mesophyU cells. Furthermore the anatomical features suggested that C. wchryma-jobi was an NADP-ME species. Stomatal conductance (g,) to assimilation (g,/A) indicated an increase in A with decrease in g" an essential feature of improving water use efficiency (WUE), but one which drastically reduces CO, diffusion rate. The physical lintitation (stomatal lintitation, t) to CO, diffusion under various [0,] and temperatures, but constant PPFD, did not exhibit statistically significant change in t values at either 0 or 21% a, within each temperature regime, however there was a marked decrease in t as the plant approached its optimum photosynthetic temperature.
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  • Date Issued: 1992

The microbial production of polyphenol oxidase enzyme systems and their application in the treatment of phenolic wastewaters

  • Authors: Scherman, Patricia Ann (neé Goetch)
  • Date: 1992
  • Subjects: Phenol oxidase Water -- Purification -- Biological treatment Enzymes -- Regulation
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4047 , http://hdl.handle.net/10962/d1004108
  • Description: Phenolic compounds are a group of organic chemicals present in the wastewaters of many synthetic industrial processes. Due to their extreme toxicity to man and animals, and deleterious impact on the environment, a range of techniques exist for the effective treatment and disposal of these pollutants. Biological degradation using microbial enzymes presents a valuable alternative to conventional wastewater treatment systems. This research was therefore initiated to investigate the polyphenol oxidase enzyme system and the feasibility of its application for effluent treatment and studies in organic solvents. The enzyme system is widely distributed in nature, with Agaricus bisporus (the common mushroom) being the best known producer. Biochemical investigations of the enzyme system were therefore carried out using this extract. A screening programme was initiated to identify microbial polyphenol oxidase producers which could be cultured in liquid media, thereby enabling the production of large quantities of enzyme in fermentation systems. Extensive growth optimization and enzyme induction and optimization studies were carried out on selected cultures. A number of good producers were isolated, namely a bacterial culture designated AECI culture no. 26, Streptomyces antibioticus, Streptomyces glaucescens and a manipulated strain, Streptomyces lividans (pIJ702). Enzyme production by Agaricus bisporus mycelia was optimized in deep-liquid culture; enzyme extracts showed high phenol removal efficiencies. Streptomyces antibioticus, Streptomyces glaucescens, Streptomyces lividans (pIJ702) and AECI culture no. 26 whole cells were also investigated for phenol-removing ability in simulated phenolic effluents. The use of whole cells reduces enzyme inactivation and instability due to the protection of the enzyme system within the cell. All cultures showed improved removal efficiencies in phenolic growth media. These results strongly suggest their use for phenol removal in continuous systems.
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  • Date Issued: 1992

The psychological sequelae of involvement in combat: a preliminary investigation

  • Authors: Hodgson, Shane Ralph Colin
  • Date: 1992
  • Subjects: War -- Psychological aspects , War victims -- Mental health , Post-traumatic stress disorder
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:2993 , http://hdl.handle.net/10962/d1002502 , War -- Psychological aspects , War victims -- Mental health , Post-traumatic stress disorder
  • Description: The psychological sequelae of being involved in combat are only recently coming to be understood. Most of the available data are from research conducted on help-seeking Vietnam veterans in the United States, and very little work has been done in South Africa. There does not as yet appear to be any instrument designed specifically to detect combat-related psychopathologies amongst soldiers who are still in active service, either in the USA or in South Africa. Combat involvement has been shown to lead to a high incidence of combat stress reaction. This in turn has shown that it can predispose sufferers to the development of a Post-traumatic Stress Disorder. It is thus expected that there would be significantly higher incidences of reported symptoms of stress disorders amongst soldiers exposed to high levels of combat as compared with a similar group of soldiers who had no combat involvement. This study used a self-reporting questionnaire, developed in the USA but adapted for use in South Africa, to allow the soldiers in the study to rate the severity of various symptoms derived from the DSM-III criteria for Post-traumatic Stress Disorder. A Beck Depression Inventory was also administered to eliminate any persons who nay have been exhibiting symptoms of depression, as this would have confounded the results. Both questionnaires were administered to serving members of the Permanent Force of the South African Defence Force, with one group being members of various high-combat units based in what was then South West Africa, and the other group being non-combat or Headquarters elements. As a precondition of the study, absolute confidentiality of the respondents and their units was maintained. The study found the expected higher scores in the high-combat group, and also showed that the Keane questionnaire has a good coefficient alpha in South Africa. The study closes with several recommendations for further research, especially in the light of the new PTSD criteria in the DSM-IIIR.
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  • Date Issued: 1992

The redemption of 'all sorrows': King Lear, The Old Curiosity Shop, and A Tale of Two Cities

  • Authors: Jacobson, Wendy
  • Date: 1992
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/457790 , vital:75679 , https://hdl.handle.net/10520/AJA1011582X_127
  • Description: In both The Old Curiosity Shop (1840-41) and A Tale of Two Cities (1859) a young girl takes care of an old man who is, or has been, de-ranged; and he has hanned her in some way. This shared motif has its source in the death of Cordelia, in particular the rendering of that scene by William Charles Macready in his historic production with which Charles Dickens was involved as advisor and consultant (one of" the company of his cabinet" as Macready's biographer has it (Downer, 170»." The role of Lear was one of Macready's most famous", writes Paul Schlicke: Its significance lies in the fact that for his production Macready returned to the original text of the play and threw out Nahum Tate's adaptation, which, introducing a romantic love story between Cordelia and Edgar and a happy ending for Cordelia and Lear, had held the English stage for a century and a half.
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  • Date Issued: 1992

The relationship of general retention ability to new South African group test non-verbal/verbal IQ discrepancies and their academic correlates

  • Authors: Watson, Peter James
  • Date: 1992
  • Subjects: Intellect Intelligence tests -- South Africa Academic achievement -- South Africa
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1725 , http://hdl.handle.net/10962/d1003608
  • Description: Both experimental research (Robbertse,1952)and clinical observation (Kruger, 1972; van der Merwe,1978) have indicated that pupils with a Verbal IQ score 10 or more points lower than their non-Verbal IQ (termed a 'Type 1' discrepancy in the present research) on the New South African Group Test (NSAGT) show poorer academic achievement than their peers of similar ability. The present research investigates the relationship of general retention ability, as defined by Hakstian and Cattell (1978), to Type 1 discrepancies as well as to their academic correlates. One hundred and thirty-nine standard seven English-speaking boys were tested on the NSAGT and the Junior Aptitude Test (JAT) (of which tests 8 and 9 give an indication of general retention ability) and divided into a group with Type 1 discrepancies and two control groups. All three groups were matched on full-scale IQ. Comparison of these three groups, using the analysis of variance technique, showed that there was no significant difference between them in level of general retention ability or in academic performance (measured by average percentage in the final standard seven examination). While no significant difference was found between the three groups regarding the relationship of general retention ability to academic performance, in the Type 1 discrepancy group the relationship of rote memory (JAT test 8) to academic performance differed markedly from that of associative memory (JAT test 9) to academic performance. In the Type 1 discrepancy group rote memory was highly associated with academic performance, possibly indicating a compensatory strategy for the lower Verbal ability in this group, enabling it to achieve academically on par with the control groups, contrary to what would be expected on the basis of Robbertse's (1962) findings. In terms of Jensen's (1982) Level 1/Level 11 theory of intelligence, it appears from the present research that rote memory ability (JAT test 8) varies between being a Level 11 ability (in the Type 1 discrepancy group) to acting as a Level 1 ability in the two control groups. The present research questions Verwey and Wolmarans's (1980) description of both JAT tests 8 and 9 as simple measures of retention Test 9, in particular, appears to function consistently as a Level 11 ability.
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  • Date Issued: 1992

The role of the queen in wax secretion and comb building in the Cape honeybee, Aps mellifera capensis (Escholtz)

  • Authors: Whiffler, Lynne Anne
  • Date: 1992
  • Subjects: Honeybee Honey, Comb Beeswax Bee culture -- Queen rearing
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5763 , http://hdl.handle.net/10962/d1005451
  • Description: The role of the queen in wax secretion and comb building was studied in the the Cape honeybee, Apis mellifera capensis (Escholtz). The percentage of bees bearing wax and the amount of wax borne by these bees did not differ between the experiments. This meant that the queenless and queenright colonies had the potential to construct equal amounts of comb as the amounts of wax available for comb building was the same. Contrary to this prediction, queenright colonies constructed 8 times more comb than their queenless counterparts. Queenright Apis mellifera scutellata colonies constructed 4 times more comb than their queenless counterparts. The increased amount of 9-oxo-2-decanoic acid (90DA) in the A.m.capensis mandibular gland secretions could not alone account for this difference. In fact, A.m.capensis and A.m.scutellata colonies constructed similar amounts of comb when they were given their own queens or queens from the other race. Worker bees need to have direct contact with their queen for comb building to be enhanced. Even when the queen had her mandibular glands extirpated and tergite glands occluded large amounts of comb were constructed than when access to the queen was limited. Direct access to the head of a mated queen proved to be the stimulus enhancing comb building. No comb was constructed when the workers had access to the abdomen of the queen. Virgin queens did not stimulate comb building. The relatively large amounts of 90DA and 9HDA from the mandibular glands of Cape virgin queens had not influenced comb building. Worker sized cells were generally constructed. These cells were slightly smaller than those constructed by European honeybees, but were indicative of African bees. A few queen less colonies constructed cells that were of an intermediate drone and worker size. Four mandibular gland pneromones were measured by gas chromatography. No correlations between these pheromones and the comb construction measurements were found. It is unlikely that the mandibular gland pheromones are the only pheromones that stimulate comb building. Pheromones from other glands on the head may contribute towards the enhancement of comb building, and they are not present in virgin queens
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  • Date Issued: 1992

The role of the teachers' centre in the professional development and in-service training of teachers with specific reference to the East London Teachers' Centre

  • Authors: Badenhorst, John Henry
  • Date: 1992
  • Subjects: Teachers -- In-service training -- South Africa , Education -- South Africa -- East London , Professional education -- South Africa , Educational change -- South Africa
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1755 , http://hdl.handle.net/10962/d1003639 , Teachers -- In-service training -- South Africa , Education -- South Africa -- East London , Professional education -- South Africa , Educational change -- South Africa
  • Description: Teachers' Centres are one of the means whereby teachers needs for in-service education and training (Inset) can be met. The professional basis of Teachers' Centres as providers of in-service education and training derives from the need of teachers to develop professionally throughout their careers. Aspects which need to be considered are the need for professional growth and the professional nature of teaching. The effective provision of in-service training requires a knowledge of effective in-service training practise and the barriers that could be encountered in presenting it. Central to any Inset for teachers would be the teachers' needs for such activity. Following on a general statement of teachers needs for Inset the role of the Teachers' Centre in meeting these needs will be examined. Teachers' Centres have specific advantages in meeting certain areas of need for Inset by teachers. A knowledge of the professional activities of teachers activity and methods of establishing the needs for Inset of teachers should promote the effective provision of these programmes. The teacher as an adult learner is important to effective Teachers' Centre operation and the nature of adult learning and variables which affect it will determine the Teachers' Centre reaction in providing Inset. Subject study group activity is very important in Teachers' Centres in the Cape Province and the principles involved in their operation together with practical considerations regarding their operation are important in the provision of Inset. The practical application of theory is illustrated by examples from the East London Teachers' Centre with an emphasis on organisation and the creation of a climate within the Centre for the existence of study groups. The presentation methods used in these study group activities are important and will vary according to the needs of the study group. The selection of methods together with the organisation of presentations and practical methods used in presentation will have an important effect on how they operate. Teachers' Centres have a role to play in promoting change and innovation in schools. The theories of promoting innovation and the roles of the change agent are important. Practical examples from the East London Teachers' Centre are provided. This research, thus, provides a theoretical study of the role of Teachers' Centres in meeting some of the inset needs of teachers as well as practical examples of such activities.
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  • Date Issued: 1992

The status of the American bollworm, Heliothis armigera (Hubner) (Lepidoptera : Noctuidae), on sunflower in the central Transvaal

  • Authors: Von Maltitz, Emil Friedrich
  • Date: 1992
  • Subjects: Helicoverpa armigera , Noctuidae -- South Africa -- Transvaal , Noctuidae , Sunflowers -- Diseases and pests
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5773 , http://hdl.handle.net/10962/d1005461 , Helicoverpa armigera , Noctuidae -- South Africa -- Transvaal , Noctuidae , Sunflowers -- Diseases and pests
  • Description: Sunflower production in South Africa has increased four fold since the 1970's. This study was done to elucidate the pest status of Heliothis armigera (Hiibner) on sunflower. Field studies were undertaken at Warmbaths, Brits and Delmas during the summer seasons of 1988/89 to 1990/91. The infestations at the latter two areas were negligible throughout the study period and their statistics have not been included in this thesis. Plant development and oviposition by natural H. armigera populations were found to be correlated as, regardless of planting date, oviposition started at six to seven weeks after planting; when the flowering stage began. A peak in egg numbers was reached by the tenth week with an average for the three seasons at two eggs per plant. The eggs were laid singly on the bracts and bases of the flower buds. A peak in larval numbers was reached at the thirteenth week after planting with the average for the three seasons of 0,4 larvae per plant. The preferred feeding sites were on, between and under the bracts from where the larvae burrow into the pithy tissue of the receptacle. Only six percent of the larvae were found feeding directly on the achenes. Eggs and larvae collected were reared to determine the degree of parasitism. Overall, 19% of the eggs were parasitised; 18% by Telenomus ullyetti Nixon (Scelionidae) and one percent by Trichogrammatoidea lutea (Trichogrammatidae). Larval parasitism at Warmbaths was 23% in 1988/89, 27% in 1989/90 and 34% in 1990/91. Of the parasitised larvae, 44% succumbed to Palexorista prob. laxa (Tachinidae). The remainder were unidentified Braconidae and Ichneumonidae. Predators, such as chrysopids, were observed during the study but their effect on egg and larvae numbers was not studied in detail. A polyhedral virus occurred late in the seasons and caused mortality of the larvae. The low numbers of H. armigera on sunflower, the slight damage to the crop and the reasonably high rate of parasitism, all seem to indicate that H. armigera is not an economica1ly important pest of sunflower and that additional control methods are not justified.
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  • Date Issued: 1992

The surface geology of the Lavino Chrome Mine of the farm Grootboom 336KT, eastern Transvaal

  • Authors: Tinney, Christopher Bruce
  • Date: 1992
  • Subjects: Chromium ores -- Geology -- South Africa -- Mpumalanga
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5067 , http://hdl.handle.net/10962/d1013404
  • Description: A mapping project of the surface geology of the Lavino chrome mine and its surroundings was initiated in order to establish the surface geological relationships in the area. In so doing the chromitite layer presently being mined has been identified and potential exploration targets in the area have been outlined. The Lavino Chrome mine field area is situated within the eastern lobe of the Bushveld Igneous Complex. The area is bounded by in the north by the Steelpoort Lineament, in the west by the Dwars River fault and in the east by the contact with the Transvaal Sequence floor rocks. Layered igneous rocks (pyroxenites, norites and anorthosites) of the Rustenburg Layered Suite dominate the geological landscape at the Lavino mine. The fact that outcropping igneous rocks of the Critical Zone abut directly against the quartzite floor rocks on the mine property makes this area unique in the Bushveld Complex. The hills in the field area are capped by mafic/ultramafic iron-rich sheet - like bodies. Extensive strike-slip faulting is seen in outcrop in the area to the north/northwest of present mining operations. On the basis of field relationships, the main chromitite layer presently being mined at Lavino is identified as the Middle Group chromitite layer MG 1. Three other prominent chromitite layers stratigraphically associated with MG 1 are identified as the Middle Group chromitites MG 2, MG 3 and MG 4. Several other less prominent outcropping chromitite layers are tentatively identified as those belonging to the Lower and Upper group of chromitites. The disconformable nature of the contact between the layered igneous rocks and the Transvaal Sequence floor rocks has resulted in the development of a wedge of undifferentiated pyroxenites in the north of the field area. The economically important LG 6 chromitite layer may be developed in subcrop within this wedge.
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  • Date Issued: 1992

The tonology of Xhosa

  • Authors: Claughton, John Sellick
  • Date: 1992
  • Subjects: Xhosa language -- Tone
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:3596 , http://hdl.handle.net/10962/d1002171
  • Description: This thesis is an examination of the tonology of Xhosa. After an initial survey of the surface tones of the language, and a review of previous studies of Xhosa tone, a description is given of the major tonal patterns of Xhosa noun and verb morphology. In the course of this description the major tonologica1 rules are allowed to emerge. In particular it is shown that some of these rules lead to complex patterns of variation in the pronunciation of the same individual. The derivation of the tone patterns of adjectives and relatives is discussed and it is shown that these tone patterns offer partial support for the derivation of some adjective and relative constructions as derived from embedded sentences but also support for deriving simple attributive adjective constructions by means of phrase structure rules. Some interesting tonal patterns such as that shown by reduplicated stems are then explored. The tones of loan words are then investigated and evidence for the identification of English and Afrikaans stress with high tones by Xhosa speakers is adduced. In the final chapter certain general problems of Xhosa tone are discussed. In particular it is argued that attempts to interpret the tonal system in terms of an accent are unrevealing and also it is suggested that attempts to unify the various rules that spread tones to the right are mistaken. In the appendices a comprehensive survey of the tones of Xhosa inflections is given together with a substantial list of Xhosa words with the tones marked.
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  • Date Issued: 1992

The university and a free society

  • Authors: Bengu, S M E
  • Date: 1992
  • Subjects: Academic Freedom -- South Africa
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/662 , vital:19979
  • Description: Has the clamour for University autonomy and academic freedom in our country not served to legitimize repression in the hands of a narrow, undemocratic “oligarchy”? Has the narrow understanding of academic freedom and university autonomy excluded the freedom of individuals and groups such as women, black communities, students, and non-academics? Before we consider the relationship that will, hope fully, exist between universities and a free society that is going to emerge in this country, we ought to accept the fact that university autonomy and academic freedom are hollow in an oppressed society such as we still have in our country.
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  • Date Issued: 1992

The utilization of tilting-filter photometry in airglow and auroral research

  • Authors: Dore, Ian Stuart
  • Date: 1992
  • Subjects: Photometry -- Research , Airglow -- Research , Auroras -- Research , Auroral photography -- Research
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5494 , http://hdl.handle.net/10962/d1005280 , Photometry -- Research , Airglow -- Research , Auroras -- Research , Auroral photography -- Research
  • Description: This thesis describes the application of tilting-filter photometry to the study of the airglow and aurora. Previous South African photometric research is reviewed. Optical instrumentation and techniques used in airglow and auroral research are reviewed. The transmission characteristics of narrowband interference filters are discussed. The analogue meridian-scanning tilting-filter photometry system used at Sanae, Antarctica is described. Shortcomings of this system have been identified, and modifications have been made to improve its spatial and temporal resolution. Details are given of the computer-controlled digital photometry system which replaced the analogue system. Equations are derived for the conversion of raw photometric data (analogue chart deflections or digital photon counts) to absolute emission intensities. The accuracy of the intensities obtained depends on the absolute calibration of the photometer, the transmission characteristics of the filter used to isolate the spectral feature of interest, and the effects of atmospheric extinction and scattering. The influence of these factors on observed emission intensities is discussed. Various models used to determine atmospheric correction factors are reviewed. It is shown that atmospheric correction factors can have a significant effect on both emission intensities and intensity ratios. The procedure used to determine the transmission characteristics of interference filters is described, as is the procedure used to cross-calibrate secondary light sources. The transmission characteristics of the filters and the brightnesses of the light sources were both found to have changed appreciably with age. The observation of a magnetospheric substorm at Sanae (L ≃ 4) is used to illustrate the use of a meridian-scanning tilting-filter photometer system in auroral research. The ratio I(557.7)/ I(391.4) observed at Sanae was found to be lower than expected, as were the OJ airglow emission intensities. A prototype digital photometer system was used aboard a ship, to observe the airglow in the region of the South Atlantic Anomaly. Significant N₂⁺ lNG emissions at 391.4 nm were measured, confirming the presence of discernable particle precipitation in the region. The 0I557.7 and 630.0 nm intensities measured from the ship were found to be lower than expected. This, combined with low airglow and auroral intensities measured at Sanae, is a cause for concern. It is recommended that further checks be made regarding the brightness of the calibration sources.
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  • Date Issued: 1992

The Viking

  • Authors: Lewis, Colin A
  • Date: 1992
  • Language: English
  • Type: text
  • Identifier: vital:6706 , http://hdl.handle.net/10962/d1006742
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  • Date Issued: 1992

Timbila movement

Timbila movement

Timbila movement

Training in note making : the effects of a training scheme on first year teacher-training students

  • Authors: Ferreira, Ignatius Leopold
  • Date: 1992
  • Subjects: Note-taking Teachers -- Training of Study skills
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1803 , http://hdl.handle.net/10962/d1003688
  • Description: This research work is based upon a training technique devised and recommended by J. Smith (1985) in a pamphlet published by The British Historical Association. The technique involves training school pupils in the making of notes from text books and references and then selecting appropriate points to answer specific questions. The technique was slightly adapted and used on a small Experimental Group drawn from Black first year College of Education students at an Eastern Cape College. A Control Group from the same College received conventional lectures on two topicS from the first year college syllabus - the San and Khoi peoples of Southern Africa. The Experimental Group was given a brief training period in Smith's technique and then worked independently on extended reading passages on the same topics. Both groups received a similar introduction of a video tape on the San and a slide presentation on the Khoi. Both groups wrote the same final test after their learning experiences were over and both groups completed questionnaires on the initial visual input and on their reactions to the learning experience. Comparisons are drawn between the results and the students' reaction to those learning experiences.
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  • Date Issued: 1992

Transkei College of Education students' perceptions of fieldwork in geographical education

  • Authors: Ngquba, Tokozile
  • Date: 1992
  • Subjects: Geography -- Fieldwork -- Study and teaching Teachers -- Training of -- South Africa -- Transkei
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1806 , http://hdl.handle.net/10962/d1003691
  • Description: The understanding of geographical concepts and the development of skills requires the use of appropriate teaching strategies. Modern school geography incorporates a wealth of techniques and embraces a wide range of strategies which are directly suited to achieve the aims which are central to current geographical education. Techniques which directly involve the learner are perceived to be the most valuable. Of the many participatory strategies suited to the teaching of geography, fieldwork is accepted as the most worthwhile. This study investigates student teachers' perceptions of fieldwork in their college studies and as a teaching strategy. Extensive literature on fieldwork in geographical education was analysed. A survey was conducted to assess the student teachers' fieldwork experiences. The results reveal that fieldwork is neglected in Transkeian schools and Colleges of Education, despite the fact that it is required by school syllabuses, and the fact that in many areas suitable sites are readily accessible. Conclusions are drawn and recommendations made for the inclusion of fieldwork in geography courses at Transkei Colleges of Education.
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  • Date Issued: 1992

Turbidity-induced changes in feeding strategies of fish in estuaries

  • Authors: Hecht, Thomas , Van der Lingen, C D
  • Date: 1992
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/446960 , vital:74573 , https://hdl.handle.net/10520/AJA00445096_644
  • Description: The aim of this study was to determine the effect of turbidity on the feeding strategies of fish in estuaries. Three species representing different feeding guilds were selected for the investigation. These were Elops machnata (representative piscivore), Pomadasys commefsonnii (a macrobenthivore) and Athefina breviceps (a planktivore). The stomach contents of these fish were examined from a clear and a turbid estuary and some experimental work was carried out on A. brevic8ps to test the hypothesis that turbidity affects feeding behaviour. Turbidity was found to have no effect on size selection of prey, but feeding rate, particularly of visual predators, was reduced at higher turbidity levels. This was caused by a decrease in the reactive distance of the fish. It would appear that in order to optimize the aquisition of food under different turbidity conditions fishes have the ability to change their feeding strategies. Visual predators are more affected by turbidity than are macrobenthic feeders.
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  • Date Issued: 1992

Understanding and treating combat-related post traumatic stress disorder: a soldier's story

  • Authors: Koen, Gary
  • Date: 1992
  • Subjects: Post-traumatic stress disorder -- Case studies , Post-traumatic stress disorder -- Treatment , Soldiers -- Mental health -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3134 , http://hdl.handle.net/10962/d1006879 , Post-traumatic stress disorder -- Case studies , Post-traumatic stress disorder -- Treatment , Soldiers -- Mental health -- South Africa
  • Description: This work documents the treatment of a 20-year-old male suffering from Post Traumatic Stress Disorder as a result of his experience during two years of national service as an Operations "Ops" Medic in the South African Defence Force. The literature review is drawn largely from the body of work emerging from the Vietnam War, and in particular the work of Robert Lifton and Erwin Parson is considered. The case study consists of a detailed synopsis of the treatment based upon material from the therapy sessions. This section hopes to accurately convey the experience of working with someone suffering from Post Traumatic Stress Disorder and provide insight into the dynamics of such a therapeutic relationship. Finally the discussion examines the links between the theory and the treatment and attempts to understand the various factors which shaped and influenced the final outcome of the therapy. Special consideration is given to showing how essentially cognitive restructuring techniques are successfully utilised within a more existential, psychodynamic framework. Furthermore, there is a paucity of literature on the subject of combat-related Post Traumatic Stress Disorder in South Africa and it is hoped that this work will both point to a need for further research in this field whilst simultaneously provide guidance for those who wish to become involved in working with individuals suffering from Post Traumatic Stress Disorder.
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  • Date Issued: 1992
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