An investigation into the use of visualisation processes as a teaching strategy to enhance number sense
- Authors: Griqua, Ronald Max
- Date: 2020
- Subjects: Mathematics -- Study and teaching -- South Africa , Mathematics -- Study and teaching -- Psychological aspects , Visualization , Number concept , RUMEP (Rhodes University Mathematics Education Project)
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/147226 , vital:38606
- Description: The literature agrees that in order to improve learning outcomes, instruction in classrooms should be improved first. Mathematics educationists therefore advocate that schools should make extensive and deep efforts to rethink their instructional programmes. Research furthermore suggests that increasingly, indicators on school performance and teaching reveal largely unacknowledged problematic teaching of mathematics in the great majority of South African schools. This research study is therefore a contribution towards rethinking the teaching strategies within mathematics classrooms. The study examined the use of visualisation processes in order to understand how these interact with the pedagogy of selected mathematics teachers when they teach number sense after participating in an intervention programme. This study argues that the effective use of visualisation processes enhanced the teaching of number sense. The research study was framed as a case study that was grounded within the interpretive paradigm. The study was located in classrooms where the participating teachers promoted active learning after taking part in an intervention programme. A constructivist theoretical underpinning was therefore adopted. At the heart of the study was the Visualisation Intervention Programme (VIP), which involved seven Rhodes University Mathematics Education Project (RUMEP) teachers within the John Taolo Gaetsewe District of the Northern Cape Province. The content of the VIP was informed by initially working with five teachers of well-resourced schools within the Northern Cape who made interesting use of visualisation processes and manipulatives to teach number sense. With the assistance of these five teachers, the VIP was then implemented by seven selected RUMEP teachers to investigate the role of visualisation processes in the teaching of number sense understandings. The study employed a mixed method approach. Qualitative data was collected through observations and interviews, while quantitative data was collected with a series of pre- and post-tests. The analysis of the findings of this research study revealed that the effective use of visualisation processes was instrumental in enhancing the teaching of number sense understandings. Furthermore, the use of visualisation processes by the selected teachers fostered independent thought and conceptual understanding of number sense topics on the part of their learners.
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- Date Issued: 2020
Bayesian accelerated life tests for the Weibull distribution under non-informative priors
- Authors: Mostert, Philip
- Date: 2020
- Subjects: Accelerated life testing -- Statistical methods , Accelerated life testing -- Mathematical models , Failure time data analysis , Bayesian statistical decision theory , Monte Carlo method , Weibull distribution
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/172181 , vital:42173
- Description: In a competitive world where products are designed to last for long periods of time, obtaining time-to-failure data is both difficult and costly. Hence for products with high reliability, accelerated life testing is required to obtain relevant life-data quickly. This is done by placing the products under higher-than-use stress levels, thereby causing the products to fail prematurely. Part of the analysis of accelerated life-data requires a life distribution that describes the lifetime of a product at a given stress level and a life-stress relationship – which is some function that describes the way in which the life distribution changes across different stress levels. In this thesis it is assumed that the underlying life distribution is the wellknown Weibull distribution, with shape parameter constant over all stress levels and scale parameter as a log-linear function of stress. The primary objective of this thesis is to obtain estimates from Bayesian analysis, and this thesis considers five types of non-informative prior distributions: Jeffreys’ prior, reference priors, maximal data information prior, uniform prior and probability matching priors. Since the associated posterior distribution under all the derived non-informative priors are of an unknown form, the propriety of the posterior distributions is assessed to ensure admissible results. For comparison purposes, estimates obtained via the method of maximum likelihood are also considered. Finding these estimates requires solving non-linear equations, hence the Newton-Raphson algorithm is used to obtain estimates. A simulation study based on the time-to-failure of accelerated data is conducted to compare results between maximum likelihood and Bayesian estimates. As a result of the Bayesian posterior distributions being analytically intractable, two methods to obtain Bayesian estimates are considered: Markov chain Monte Carlo methods and Lindley’s approximation technique. In the simulation study the posterior means and the root mean squared error values of the estimates under the symmetric squared error loss function and the two asymmetric loss functions: the LINEX loss function and general entropy loss function, are considered. Furthermore the coverage rates for the Bayesian Markov chain Monte Carlo and maximum likelihood estimates are found, and are compared by their average interval lengths. A case study using a dataset based on accelerated time-to-failure of an insulating fluid is considered. The fit of these data for the Weibull distribution is studied and is compared to that of other popular life distributions. A full simulation study is conducted to illustrate convergence of the proper posterior distributions. Both maximum likelihood and Bayesian estimates are found for these data. The deviance information criterion is used to compare Bayesian estimates between the prior distributions. The case study is concluded by finding reliability estimates of the data at use-stress levels.
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- Date Issued: 2020
Foraging for fruits: natural resource use and its conservation potential in urban environments
- Authors: Sardeshpande, Mallika
- Date: 2020
- Subjects: Non-timber forest products , Wild plants, Edible , Urban plants , Urban ecology (Biology) , Open spaces , Environmental protection -- Citizen participation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167465 , vital:41483
- Description: Wild edible fruits (WEFs) are a type of natural resource that humans across the world collect from diverse natural landscapes. They are among the most used non-timber forest products (NTFPs) and wild foods, and often serve more than a nutritional purpose for humans, in the form of fibre, fuel, medicine, and other products. The use of WEFs may augment household dietary diversity, food security, and income in some contexts. The prevalence of WEF species across the spectrum of natural to modified ecosystems presents the potential for integrated landscape-level conservation efforts centred on these species. The first half of this thesis investigates the state of knowledge about this versatile and ubiquitous resource in the wider context of other wild foods and NTFPs, and compares the patterns of use of WEFs with those of other wild foods and NTFPs. Through these studies, I find that WEFs are indeed a widely occurring, resilient, and useful resource along the rural-urban gradient. They are unique in that their use transcends the geographical and socio-economic criteria that influence the use of other wild foods and NTFPs. Based on these findings, in the second half of the thesis, I propose the use-based conservation of WEF species in urban landscapes through the practice of urban foraging. Through interviews with urban land managers and foragers, I describe the state of urban green space management and urban foraging, and identify synergies between the two. Green space management is increasingly devolved and well-defined in developed cities, and relatively diffused in smaller towns, but nevertheless supportive of use-based biodiversity conservation. Planting and foraging for WEFs in urban green spaces ties in with local and national objectives of urban land use management policy. However, the lack of information on species, spaces, and sustainability related to foraging are a hindrance to addressing this activity and harnessing its conservation potential. Foragers use a variety of WEF species collected from natural as well as highly used and urbanised areas in their cities. Although most foragers consider foraging as a cultural and recreational activity, many of them agreed with the prospect of commercialising or popularising it to protect and promote the biodiversity and culture associated with their foraging spaces. The synthesis of this study presents four possible pathways to conserve the diversity of WEF species, and to extend the benefits of WEF use to landscape stewardship. It identifies key stakeholders in implementing these pathways and possible collaborations between these stakeholders; the multiple conservation objectives and policies these pathways respond to; and context-specific considerations for policy and implementation related to planting and foraging of WEFs.
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- Date Issued: 2020
Combined spectral and stimulated luminescence study of charge trapping and recombination processes in α-Al2O3:C
- Authors: Nyirenda, Angel Newton
- Date: 2018
- Subjects: Luminescence , Thermoluminescence , Luminescence spectroscopy , Carbon-doped aluminium oxide , Radioluminescence , Time-resolved X-ray excited optical luminescence
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62683 , vital:28235
- Description: The main objective of this project was to gain a deeper and better understanding of the luminescence processes in a-Al₂O₃:C, a highly-sensitive dosimetric material, using a combined spectral and stimulated luminescence study. The spectral studies concentrated on the emission spectra obtained using X-ray induced radioluminescence (XERL), thermoluminescence (XETL) and time-resolved X-ray excited optical luminescence (TR-XEOL) techniques. The stimulated luminescence studies were based on thermoluminescence (TL), optically stimulated luminescence (OSL) and phototransferred TL (PTTL) methods that were used in the study of the radiation-induced defects at high beta-doses and the deep traps, that is, traps with thermal depths beyond 500°C. The spectral and stimulated luminescence measurements were carried out using a high sensitivity luminescence spectrometer and a Ris0 TL/OSL Model DA-20 Reader, respectively. The XERL emission spectrum measured at room temperature shows seven gaussian peaks associated with F-centres (420 nm), F+-centres (334 nm), F2+-centres (559 nm), Stoke’s vibronic band of Cr3+ (671 nm), Cr3+ R-line emission (694 nm), anti-Stokes vibronic band of Cr3+ (710 nm) and an unidentified emission band (260-300 nm) which we associate with hole recombinations at a luminescence centre. The 694-nm R-line emission from Cr3+ impurity ions is most likely due to recombination of holes at Cr2+ during stimulated luminescence and as a result of an intracentre excitation of Cr3+ in photoluminescence (PL) due to photon absorption. The Cr3+ emission decreases in intensity, whereas the intensity of F-centre emission band is almost constant with repeated XERL measurements. Depending on the amount of X-ray irradiation dose, both holes and/or electrons may take place in the emission processes of peaks I (30-80°C), II (90-250°C) and III (250-320°C) during a TL readout, albeit, electron recombination is dominant regardless of dose. At higher doses, the XETL emission spectra indicate that the dominant band associated with TL peak III (250-320°C) in the material, shifts from F-centre to Cr3+. Using the deep-traps OSL, it has been confirmed that the main TL trap is also the main OSL trap whereas the TL traps lying in the temperature range of 400-550°C constitute the secondary OSL traps. There is evidence of strong retrapping at the main trap during optical stimulation of charges from the secondary OSL traps and the deep traps and that the retrapping occurs via the delocalized bands. At high-irradiation beta-doses, aggregate defect centres which significantly alter the TL and OSL properties, are induced in the material. The induced aggregate centres get completely obliterated by heating a sample to 700°C. The radiation-induced defects cause the main TL peak to shift towards higher temperatures, increase its FWHM, reduce its maximum intensity and cause an underestimation of both the activation energy and order of kinetics of the peak. On the other hand, the OSL response of the material is enhanced following a high-irradiation dose. During sample storage in the dark at ambient temperature, charges do migrate from the deep traps (donors) to the main and intermediate traps (acceptors) and that the major donor traps during this charge transfer phenomenon lie between 500-600°C.
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- Date Issued: 2018
Intergenerational learning and environmental care: a case of a fishing community next to Africa’s first marine protected area
- Authors: Cloete, Cindy-Lee
- Date: 2017
- Subjects: Tsitsikamma Marine Protected Area (South Africa) , Covie (South Africa) , Intergenerational relations -- South Africa -- Covie , Intergenerational communication -- South Africa -- Covie , Fishing villages -- South Africa -- Covie , Sustainable fisheries -- South Africa -- Covie , Environmental education -- South Africa -- Covie
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/7598 , vital:21277
- Description: This study explored the relationship between intergenerational learning and environmental care in the small fishing community of Covie, located next to the Tsitsikamma Marine Protected Area (TMPA) on the south-eastern coast of South Africa. Since Covie’s establishment as a woodcutter settlement in 1883, the community has depended on the marine and coastal environment such that their communal identity and basic means of subsistence are closely tied to their traditional fishing practices. Since its proclamation in 1964, the TMPA has undergone numerous policy changes, most notably the complete closure of the TMPA to fishing in 2001. Against this backdrop, the study sought to understand how intergenerational learning about fishing practices are mediated in Covie and the ways in which such learning processes constitute a sense of place and belonging for the Covie fishers, and to develop a sense of care for the natural environment. The study included 12 Covie community members of different generations and genders so as to be representative of the community (approximately 86 members). The research was informed by qualitative data generated through a focus group discussion with eight Covie community members, a mirror workshop with the same eight community members, eight semi-structured interviews, and five naturalistic observations of fishing practices. Data generation and analysis was informed by Etienne Wenger’s theory of Communities of Practice which was complemented by theoretical perspectives on intergenerational learning and attachment to place. This study found that the Covie fishers indeed operate as a community of practice who depend significantly on intergenerational learning processes to transfer knowledge, skills and values about fishing practices to younger generations. The 2001 policy changes that denied the Covie fishers access to their traditional fishing sites were shown to reduce the participation in fishing of a range of community members (in particular children and women), which in turn influenced forms of intergenerational learning about fishing. The youth’s reduced participation especially was linked to more protracted and fragmented processes of learning about fishing and Covie’s code of fishing conduct, including its underpinning sense of environmental care. Finally, this study argues that the affective and socio-material connections to their natural surroundings have shaped the Covie community’s sense of care and responsibility toward the environment.
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- Date Issued: 2017
The performance of hearing impaired children on the Revised Extended Griffiths Scales
- Authors: Schröder, Ingrid Anita
- Date: 2004
- Subjects: Psychological tests for children -- South Africa , Griffiths Developmental Scales , Deaf children -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11031 , http://hdl.handle.net/10948/333 , Psychological tests for children -- South Africa , Griffiths Developmental Scales , Deaf children -- South Africa
- Description: In this unique time of nation building in South Africa, education is seen as the key foundation stone to prosperity and development. However, despite a decade of restructuring, many differing groups of children still do not receive the quality of education they deserve. Amongst those are children with special needs, including those who have a hearing impairment. These children are the focus of the present study. It is a widely accepted principle that early assessment and intervention is necessary to maximise a child’s potential. It is for this reason that the global aim of this study was to explore and describe the developmental profile of hearing impaired children on the Revised Extended Griffiths Scales. Further aims were to compare the performance of the clinical sample to a normal South African sample. A quantitative, exploratory-descriptive research design was employed. The sample of hearing impaired children (N = 58), between the ages of 36 and 95 months, attended the Carel du Toit Pre-School in the Western Cape, South Africa and were obtained by means of a non-probability, purposive sampling procedure. The normal sample (N = 58) was drawn from an existing database created for the revision of the Scales. Information was collated using clinical files, biographical data as well as the results of an assessment on the Revised Extended Griffiths Scales. The major findings of the study are summarised below. The general performance of the hearing impaired sample on the Revised Extended Griffiths Scales was average. The performance of the children on the six subscales ranged from below average to average, with major fall-outs occurring on the Hearing and Speech and Practical Reasoning Subscales. The normal sample performed significantly better than the hearing impaired sample on all of the subscales of the measure. However, significant differences were found on four of the six subscales, namely, the Locomotor, Personal-Social, Hearing and Speech and Practical Reasoning Subscales. Generally, the results of the current study suggest that a specific developmental profile is obtained for hearing impaired children. In addition, this study has highlighted the success with which the Revised Extended Griffiths Scales can be utilised on a hearing impaired population.
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- Date Issued: 2004
An exploration of adolescent risk-taking behaviour : a case study analysis
- Authors: Dietrich, Valerie
- Date: 2003
- Subjects: Teenagers -- South Africa -- Conduct of life , Risk-taking (psychology) in adolescence
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10989 , http://hdl.handle.net/10948/312 , Teenagers -- South Africa -- Conduct of life , Risk-taking (psychology) in adolescence
- Description: Do adolescents of colour really engage in risk-taking behaviours as often generalised by the public? Are they in fact the alcohol, drugs, sex, and violence generation? This study attempts to investigate the conditions influencing the choices adolescents make prior to their engaging in risk-taking behaviours. In the social sciences, concerns over adolescents’ recklessly irresponsible behaviours have deep roots. In 1904 G. Stanley Hall depicted adolescence as misbehaving because of the storms and stresses of the transition from childhood to adulthood. Subsequently, social scientists produced substantial evidence that the storminess of adolescence is largely an over generalisation, which has not been empirically substantiated. In corroboration of this interpretation, this study also indicates that not all adolescents engage in risk-taking behaviour, and those risky individuals do not necessarily engage in all spheres of risk-taking. The majority of the target group only experimented with certain risk behaviours by engaging in them on one occasion only. The specific high school was selected because the researcher knew the learners, as she was an educator there at the time. She was thus reasonably aware of the frequency, the nature and the severity of the risk-taking behaviours of the target group. In general, the most important findings of the study signified a moderate level of participation in risk-taking activities. However, in certain spheres such as cigarette smoking, alcohol usage and sexual intercourse, an extreme participation level was reported. Certain factors such as gender, age, socio-economic conditions, parental (one or both) absence, and the respondents’ attitude towards the specific behaviour, were discovered to have played an influential role in the target group taking risks. Based on the reasons advanced for engaging in risk-taking behaviour, the researcher concluded that the following theories were applicable in explaining the behaviour of the respondents. These theories are the social learning theory, symbolic interactionist theory, social identity, the theory of reasoned action, and Maslow’s hierarchy of needs. The researcher trusts that this study will assist the reader to understand the complex contributing circumstances that the target group has to contend with in making decisions.
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- Date Issued: 2003
Transcendence in Patrick White: the imagery of the Tree of Man and Voss
- Authors: Van Niekerk, Timothy
- Date: 2003
- Subjects: White, Patrick, 1912-1990. Tree of man , White, Patrick, 1912-1990. Voss
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2254 , http://hdl.handle.net/10962/d1004269 , White, Patrick, 1912-1990. Tree of man , White, Patrick, 1912-1990. Voss
- Description: This study represents an exploration of White's concept of transcendence in The Tree of Man and Voss by means of a detailed account of some of the key patterns of imagery deployed in these novels. White's imagery is a key mode of expression in his work, not simply manifesting in overarching religious symbols and framing structures but figuring in constantly modulated tropes continuous with the narrative, as well as in minor, but no less significant images occasionally susceptible to etymological or onomastic reading. While no attempt is made to provide an exhaustive exploration of the tropes at work in these novels, a sufficient range of material is covered, and its metaphoric density adequately penetrated, to highlight and explore a fundamental concern in White's work with a paradoxical unity underlying the dualities inherent in temporal existence. A useful way of approaching his fiction is to view the perpetual modulations of his imagery as the dramatisation of an enantiodromia or play of opposites, in which the conflicts of duality are elaborated and paradoxically - though typically only momentarily - resolved. This resolution or coincidence of opposites is a significant feature of his notion of transcendence as well as his depictions of illuminatory experience, and in this respect White's metaphysics share an essential characteristic, not only of Christianity, but a range of religious and mythological systems concerned with expressing a transcendent reality. Despite these analogies, however, the novels at hand are not so tightly bound to Christian, or any other, meaning-making systems so as to constitute sustained allegories, and hence this study does not aim to chart a series of correspondences between White's images and biblical or mythological symbols. Indeed, a criticism often levelled at White - with The Tree of Man and Voss typically figuring in support of this claim - is that he too rigidly imposes religious frameworks on his work. An extension of this view is formulated in the Jungian critique of White's corpus offered by David Tacey, who argues that White's conception of transcendence is consistently challenged by the archetypal significance of the images he employs, which point to a contrary process of psycho-spiritual regression in his protagonists. In a fundamentally text-based approach, this study explores White's use of imagery while taking biblical resonances and archetypal interpretations into account, and suggests that, though White's images are highly allusive, they are not merely agents of imported Christian, or other traditional symbolic values. Nor do they undermine the authenticity of his depiction of the spirituality of his protagonists, or obtrude on the fabric of the narrative. Instead, the range of his images are - though often ambivalent - integral to a network of mercurial tropes which articulate and constantly evaluate a notion of transcendence through inflections and oscillations rather than equations of meaning.
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- Date Issued: 2003
An examination of the factors underlying decision-making about selection and presentation of photographs of political conflict in South African newspapers
- Authors: O'Dowd, Catherine Frances
- Date: 1997
- Subjects: Photojournalism , Photojournalism -- South Africa , Photojournalists -- South Africa , South Africa -- Politics and government -- 1989-1994
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3478 , http://hdl.handle.net/10962/d1002933 , Photojournalism , Photojournalism -- South Africa , Photojournalists -- South Africa , South Africa -- Politics and government -- 1989-1994
- Description: What newspaper readers see of an event is detennined by what photographs are seley ted and how they are presented. This thesis attempts to deconstruct the decision-making process around selection and presentation of photographs, with the aim of detennining what factors are taken into account in that process. It is based on the hypothesis that there must be a number of factors involved in decisions about news photographs, although these factors may not necessarily be consciously acknowledged in the decision-making process. The study involves a comparison of how five case studies of incidents of political violence, which occurred between 1990 and 1994 in South Africa, were used'in lrinewspapers. The focus on images of political violence is based on the assumption that politically and visually controversial images will give rise to situations in which gatekeepers will be caned upon to question their decisions. The research is based on qualitative research interviews with the decision-makers involved in the case studies. The analysis of the decision-making procedures is based on the theory of gatekeeping. The interviews are analysed in terms of Lewin's theory offqrces, which suggests that, depending on the context, some factors will manifest themselves as positive forces working in favour of the photograph being selected or well presented, while others will take the form of negative forces. The analysis sets out to determine what factors were taken into account in the decision::making process, what detennined their relative degrees of importance and how those relative degrees of importance determined the final outcome. Following an introduction to the practical case study research, dealing with general issues such as picture policy in newspapers and decision-making procedures, each case study is dealt with in turn. After an outline of the context in which the event occurred, the kinds of pictures that were available to the newspapers are described. Then the decisions taken about which to choose and how to use them are analysed in terms of dominant themes. These are themes such as newsworthiness, gruesomeness of content and concern abo!Jt what other media were using. The analysis examines the way the news context and the decision-making context determine the relative importance of the various factors present. Finally the study looks at the conclusions that can be drawn from the five case studies. The conclusion supports the initial hypothesis in finding that these decisions can be shown to have their basis in a fairly limited set of factors. The different results, from study to study and from newspaper to newspaper within a study, are determined by the changing news context and the decisi~n-making context.
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- Date Issued: 1997