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Biochemical characterisation of Pfj2, a Plasmodium falciparum heat shock protein 40 chaperone potentially involved in protein quality control in the endoplasmic reticulum

  • Authors: Afolayan, Omolola Folasade
  • Date: 2013
  • Subjects: Plasmodium falciparum Endoplasmic reticulum Heat shock proteins Malaria , Mosquito-borne infectious disease
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:3883 , http://hdl.handle.net/10962/d1001617
  • Description: Plasmodium falciparum is a protozoan parasite that causes a severe form of malaria, a mosquito-borne infectious disease in humans. P. falciparum encodes a number of proteins to facilitate its life-cycle, including a type II heat shock protein 40 (Hsp40), Pfj2. Pfj2 shows a degree of homology to human ERdj5, a resident protein of the endoplasmic reticulum (ER) that promotes protein quality control by facilitating the degradation of misfolded proteins. The overall aim of this study was to further understand the function of Pfj2 in the P. falciparum cell by characterising it biochemically. A bioinformatic analysis of Pfj2 was carried out to enable the identification of a potential ER signal sequence and cleavage site. Furthermore, an analysis of Pfj2 protein sequence was performed to compare domain similarities and identities with typical type II Hsp40s namely, human ERdj5, S. cerevisiae Sis1, human Hsj1a and human DnaJB4. The method used included the insertion of the codon-optimised coding sequence for the processed ER form of Pfj2 into the prokaryotic expression vector, pQE30, to enable overproduction of a histidine-tagged protein. A 62 kDa His₆-Pfj2 was successfully expressed in Escherichia coli and purified using denaturing nickel affinity chromatography. ATPase assays were performed to determine the ability of His₆- Pfj2 to stimulate the chaperone activity of the ER Hsp70, also called immunoglobulin binding protein (BiP). Initial studies were conducted on readily available mammalian His₆-BiP as a control, which was shown to have an intrinsic activity of 12.07±3.92 nmolPi/min/mg. His₆- Pfj2 did not stimulate the ATPase activity of mammalian His₆-BiP, suggesting that it either could not act as a co-chaperone of mammalian His₆-BiP (specificity), or it required a misfolded substrate in the system. Therefore, ongoing studies are addressing the interaction of Pfj2 and misfolded substrates with P. falciparum BiP. The results of these studies will further our understanding of a poorly-studied parasite chaperone that represents a potential drug target for development of novel strategies for the control of a serious human disease
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  • Date Issued: 2013

Action research case studies of participatory materials development in two community contexts in Zambia

  • Authors: Lupele, Justin Kalaba
  • Date: 2003
  • Subjects: Community development -- Zambia -- Case studies Environmental education -- Zambia -- Case studies Sustainable development -- Zambia -- Case studies
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1417 , http://hdl.handle.net/10962/d1003298
  • Description: This research reports on two action research case studies of participatory materials development in two rural community contexts in Zambia, namely Chiawa and Nalusanga. It aims to explore and articulate the relationships between community-based environmental education and participatory materials development in the WWF Zambia Education Project context; clarify participatory materials development processes by identifying the roles of different ‘actors’ in these processes and identify and analyse the contextual and other factors that may influence development and use of environmental education materials in rural communities. These aims were explored by means of a number of action research cycles of inquiry in the two communities. The study also articulates the significance of considering ambivalent globalising influences such as international conferences, debates, overseas development aid, national policies and how these shape and influence materials development work in a local context. In order to gain more insight into the local contexts, I developed contextual profiles on the two communities. These capture the contextual factors that influenced the participatory materials development processes. They include issues such as language, ethnicity, literacy, power relations and the local social economy, amongst others. Although this study has been predominately guided by the socially critical orientation to research and education, I have drawn on aspects of other research orientations. I have also explored some of the emerging critiques of the socially critical orientation. The findings of this study reveal the different roles participants can play in participatory materials development; participatory materials development processes as a learning process; the dynamics of participation in an African context; the role of language and literacy in materials development; the need for open-ended process models of learning amongst adult learners and the importance of merging expert and local knowledge in participatory materials development. This study opens up possibilities for further exploration of participatory materials development processes within the WWF ZEP context and beyond.
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  • Date Issued: 2003

The influence of indigenous languages on Ugandan English as used in the media

  • Authors: Tukwasibwe, Constance
  • Date: 2014
  • Subjects: Mass media and language -- Uganda , Languages in contact -- Uganda , English language -- Uganda , Language transfer (Language learning) -- Uganda , Communication and culture -- Uganda , Bilingualism -- Uganda , Linguistic demography -- Uganda , Uganda -- Languages
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:3646 , http://hdl.handle.net/10962/d1015637
  • Description: When two or more languages come in contact, they influence each other in various ways, for example through word borrowing, transfer of sounds, morphology and syntax taken from one language system and imported to another. In this study, the primary concern is on the indigenous communities of Uganda learning the English language, plus the influence that this interaction brings into the linguistic space. Bringing the Ugandan multilingual situation into perspective, the study looks at how the English language has interacted with the local languages and the local speech habits, customs and traditions of the indigenous people, to the extent that it has been indigenized. Some word usage results in miscommunication due to the socio-cultural uniqueness of Ugandan cultural expressions. As an example, because of the practice of polygamy in most Ugandan cultures, words like co-wife are coined to mean 'a woman who shares a husband, or a husband's other wife', a word that is absent in both the language and culture of native English speakers. Furthermore some words are formed by calquing some indigenous language expressions, e.g. 'to eat money' or 'to eat cash', an expression that is calqued from the Luganda phrase, kulya sente. Such word coinages are meant to fill the 'shortfall' where the English language fails to provide adequate equivalents. Understanding the context of this kind of English usage and the influence from the indigenous languages is helpful in handling inter-cultural discourses, as the same expression may convey different senses to different people in different contexts. So then, this study deals with some peculiarities of Ugandan English, namely; the features of Ugandan English grammar which are influenced by the indigenous languages. Evidence from the Corpus of Ugandan English is explored to establish that indigenous languages in Uganda have a significant influence on the English language variety spoken in the country, and that a large part of English bilingual speakers cannot speak English without transferring the features from their mother tongue or indeed, switching and mixing codes. A British corpus was used for the purposes of comparison with Ugandan English. The research was conducted in Uganda, drawing data from English newspapers, radio and television talk -shows that were recorded to provide a structural analysis of the contact situations. The result of the study points to the fact that, indeed, the phonological, morpho-syntactic and semantic characteristics of Ugandan English have a considerable amount of influence from indigenous local languages. This study is hinged on the assumption that when indigenous languages and the target language come together in a linguistic contact situation, the resulting variety would exhibit distinct phonological, lexical, grammatical and semantic/pragmatic features ( cf. Sankoff, 2001; Thomason, 1995; Thomason & Kaufman, 1988; Winford, 2005). However, some of these innovations have attracted criticism from 'prescriptivists' such as Quirk (1985, 1988, 1990); Gaudio (2011); and Abbot (1991) who perceive them as 'nonstandard', 'incorrect English language usage' and a 'direct translation from the language user's mother tongue into English'. Yet, indigenous languages continue to play important roles in shaping the kind of English language usage in Uganda.
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  • Date Issued: 2014

The dramatic theory of William Hazlitt : "Imagination in criticism"

A pilot study of secondary teachers' understanding of population dynamics

  • Authors: Hockey, Athol James Temlett
  • Date: 1996
  • Subjects: Environmental education -- South Africa , Population -- Study and teaching (Secondary) -- South Africa
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1703 , http://hdl.handle.net/10962/d1003586
  • Description: Population dynamics is a South African secondary school biology syllabus topic which deals specifically with ecology or concepts within the realm of ecology. It is currently taught in a way which largely emphasises the teaching and learning of facts and concepts, often out of any context to which students can relate. While it is important to convey scientific concepts, it is just as important to address social and political issues regarding overpopulation and the environment. This research involved the administration of a questionnaire to Std 10 biology teachers in the Department of Education and Training (DET), which sought to obtain information about various aspects of teachers' teaching of population dynamics. These included their feelings toward the teaching of the specific sections of the population dynamics syllabus, and their knowledge and views of environmental issues and human population expansion. The findings of the research suggest that population dynamics is an important topic for students to learn about. The traditional teacher-centred approach to teaching is used by the teachers in the research sample. The sections considered by the teachers to be most important for learning were also considered the most interesting and the easiest to teach. The majority of the teachers in the research sample recognised that human population growth is a global and local problem and that South Africa cannot sustain its present population growth. The teachers in the sample show a diversity of opinions about sustainable development, and have a limited understanding of the links between population, poverty and consumption. Important information gained from the research will be significant in the development of a teaching and learning module on population dynamics that reflects the aims and purpose of environmental education.
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  • Date Issued: 1996

Whither state, private or public service broadcasting? : an analysis of the construction of news on ZBC TV during the 2002 presidential election campaign in Zimbabwe

  • Authors: Dlamini, Tula
  • Date: 2013-07-16
  • Subjects: Zimbabwe Broadcasting Corporation Journalism -- Political aspects -- Zimbabwe Mass media -- Political aspects -- Zimbabwe Political campaigns -- Zimbabwe Elections -- Zimbabwe Television and politics -- Zimbabwe Zimbabwe -- Politics and government -- 1980-
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3520 , http://hdl.handle.net/10962/d1008257
  • Description: The study sets out to examine the television coverage of the 2002 presidential campaign in Zimbabwe by examining the extent to which the Zimbabwe Broadcasting Corporation fulfilled the mandate of public service broadcasting. The primary objective of this study is to assess how ZBC television newscasts mediated pluralistic politics in the coverage of the country's presidential election campaign, in line with the normative public sphere principles. The thesis comprises seven chapters organized, first, with an introductory chapter, which provides the general background of the study. The chapter offers the rationale for the focus on TV rather than other media fomls . There are two theoretical and contextual chapters in which the use of both qualitative and quantitative methods is explained and findings are presented. Finally, the conclusion offers recommendations about the form broadcasting might take to fulfil a public service mandate and these include the strengthening of the public service broadcasting model along normative public sphere principles. The findings of the analysed election newscasts confirm that ZBC television election news was constructed in favour of ZANU PF at the expense of voices from other social and political constituencies. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
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Welcome at joint annual congress of S.A. Pharmacological Society, Physiological Society of Southern Africa, and Bio-medical Engineering Eociety of South Africa

  • Authors: Henderson, Derek Scott
  • Date: 1980-10-15
  • Language: English
  • Type: Text
  • Identifier: vital:7413 , http://hdl.handle.net/10962/d1018290
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  • Date Issued: 1980-10-15

The study of hydroxyoximes and hydroxamic acids supported on macroporous resins and their use in the rapid seperation of metals

  • Authors: Hemmes, Marlene
  • Date: 1979
  • Subjects: Chromatographic analysis , Separation (Technology) , Metal ions , Solvent extraction , Extraction (Chemistry) , Oximes , Metals -- Analysis
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4453 , http://hdl.handle.net/10962/d1009512
  • Description: Introduction: The macroporous Amberlite XAD resins were coated with LIX-64N and examined for the rate of uptake of copper . XAD-7 was by far the best support and gave a satisfactory rate of uptake up to loadings of 60% (w/w). The specific surface area of XAD-7 was measured by the adsorption of methylene blue from aqueous solution. The area of the wetted resin was five times less than that of the dry resin. LIX-65N was purified and the anti isomer characterised using spectroscopic techniques . The rate of uptake of copper was not improved by use of purified LIX-65N or by addition of LIX-63. XAD-7 coated with LIX-65N was used in columns. Elution curves for copper showed negligible tailing, and rapid separations of copper from iron (111), nickel, cobalt and magnesium by selective absorption were achieved. Copper was concentrated from very dilute solution at a flow rate of 50 ml min -1 ,and a 99% recovery was obtained. The method was applied to the rapid determination of copper in brass and bronze. A series of long-chain hydroxamic acids were synthesised and tested for suitability as stationary phase on XAD-7. Oleohydroxamic acid and naphthenohydroxamic acid were the most promising. The r ate of uptake of copper was reduced by the use of nonylphenol or amyl alcohol as a diluent. The capacities for copper of the hydroxamic acids were less when supported on XAD-7 than when used as liquid ionexchangers. The distribution coefficients of cobalt, nickel, zinc, lead, vanadium, uranium, iron (111) and copper were measured as a function of pH. XAD-7 coated with oleohydroxamic acid was used in columns for the rapid separation of iron (111) from copper and of copper from nickel, cobalt, lead and zinc. Copper was concentrated from very dilute solution at a flow rate of 45 ml min -1 and a 100,8% recovery was obtained. Copper was successfully separated from nickel by selective elution. The elution curves obtained show negligible tailing. The resin loaded with oleohydroxamic acid lost capacity due to chemical instability. Naphthenohydroxamic acid supported on XAD-7 was not suitable for use in columns, because it was physically unstable.
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  • Date Issued: 1979

Senior staff party 1980

  • Authors: Henderson, Derek Scott
  • Date: 1980-11-21
  • Language: English
  • Type: Text
  • Identifier: vital:7414 , http://hdl.handle.net/10962/d1018291
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  • Date Issued: 1980-11-21

An investigation into the anxiolytic properties of melatonin in humans

  • Authors: McCallaghan, Johannes Jacobus
  • Date: 1999
  • Subjects: Melatonin , Pineal gland -- Secretions
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:3772 , http://hdl.handle.net/10962/d1003250 , Melatonin , Pineal gland -- Secretions
  • Description: The purpose of this project was to investigate the role of melatonin in the pathophysiology of anxiety in humans. The literature study confirmed the intimate relationship between serotonin and melatonin. Melatonin is not only able to act as an agonist (in physiological concentrations) and an antagonist (at higher concentrations) on serotonin receptors but via control of brain pyridoxal kinase activity might have an effect on GABA, serotonin, dopamine and norepinephrine synthesis. A clinical trial to investigate melatonin's effect on anxiety in humans was conducted as a pilot study. Thirty patients complaining of anxiety participated in a liN of 1" double blind placebo controlled trial. During the experiment each subject was thus exposed to melatonin and a placebo for a week at a time on two occasions. During the first phase of the experiment, (Pair '1) patients showed a statistically significant reduction in their anxiety levels during the first period (P1P1), which was not the case during the second period (P1P2). The improvement however continued during the second phase of the experiment (Pair 2) so that there was also a statistically significant improvement during P 2 P 2 (Period 2 / Pair 2) when placebo was administered. It could not conclusively be shown that melatonin was responsible for the improvement in the patients' anxiety. The explanation for these results suggests thelt the improvement was due to a: 1) placebo effect throughout, 2) psychotherapeutic effect due to contact with a clinician, 3) melatonin induced phase shift in the patient's endogenous melatonin response curve, 4) combination of all 3 options. This pilot study lays the groundwork for a much more exhaustive study in which the melatonin of the patients is determined before melatonin is administered, the role of the clinician is clarified and the most appropriate time for melatonin administration is sought .
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  • Date Issued: 1999

Form and idea in the fiction and non-fiction of John Fowles

  • Authors: Etter, Julie-Anne
  • Date: 1986
  • Subjects: Fowles, John, 1926-2005
  • Language: English
  • Type: text , Thesis , Masters , MA
  • Identifier: vital:2179 , http://hdl.handle.net/10962/d1001830
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  • Date Issued: 1986

A comparison of WISC-IV test performance for Afrikaans, English and Xhosa speaking South African grade 7 learners

  • Authors: Van der Merwe, Adele
  • Date: 2008
  • Subjects: Wechsler Intelligence Scale for Children Wechsler Adult Intelligence Scale Intelligence tests -- South Africa Psychological tests -- Cross-cultural studies Educational tests and measurements -- South Africa Educational psychology -- South Africa Language and languages -- Ability testing Educational evaluation -- South Africa Education, Elementary -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3076 , http://hdl.handle.net/10962/d1002585
  • Description: his study builds on South African cross-cultural research which demonstrated the importance of careful stratification of multicultural/multilingual normative samples for quality of education in respect of English and African language (predominantly Xhosa) speaking adults and children tested with the WAIS-III and WISC-IV, respectively. The aim of the present study was to produce an expanded set of preliminary comparative norms on the WISC-IV for white and coloured Afrikaans, white English and black Xhosa speaking Grade 7 children, aged 12 to 13 years, stratified for advantaged versus disadvantaged education. The results of this study replicate the findings of the prior South African cross-cultural studies in respect of quality of education, as groups with advantaged private/former Model C schooling outperformed those with disadvantaged former DET or HOR township schooling. Furthermore, a downward continuum of WISC-IV IQ test performance emerged as follows: 1) white English advantaged (high average), 2) white Afrikaans advantaged and black Xhosa advantaged (average), 3) coloured Afrikaans advantaged (below average), 4) black Xhosa disadvantaged (borderline), and 5) coloured Afrikaans disadvantaged (extremely low). The present study has demonstrated that while language and ethnic variables reveal subtle effects on IQ test performance, quality of education has the most significant effect – impacting significantly on verbal performance with this effect replicated in respect of the FSIQ. Therefore caution should be exercised in interpreting test results of individuals from different language/ethnic groups, and in particular those with disadvantaged schooling, as preliminary data suggest that these individuals achieve scores which are 20 – 35 points lower than the UK standardisation.
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  • Date Issued: 2008

Review and development of environmental interpretation resources to foster environmental learning in two Kenyan schools

  • Authors: Atiti, Abel Barasa
  • Date: 2003
  • Subjects: Environmental education -- Kenya Environmental education -- Kenya -- Case studies
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1743 , http://hdl.handle.net/10962/d1003627
  • Description: This participatory action research study involved a group of teachers in transforming school grounds into interpretation resources. Approached from a critical perspective, it challenged the conventional top-down approaches to interpretation resources and materials development. Through a teacher-centred approach, a school-based ‘botanic garden’ and ‘arboretum’ were developed at Samaj and Kenya High respectively. Teachers were further actively engaged in developing a variety of interpretive materials that might engage learners in socially critical environmental education processes at the transformed sites. A process in which educators from five non-formal education organisations shared their skills and knowledge on environmental interpretation with teachers preceded the development of interpretation resources and materials. Drawing on Latour (1999), I have applied the notion of mobilising interpretive capital when describing this process. Interpretive capital within the non-formal education sector was mobilised and made available through social interactions between teachers and non-formal educators. This occurred during workshops, organisational visits and critical reviews of a sample of interpretive materials. I provide insights into how the interpretive capital was mobilised and later drawn on by teachers during the development processes in their schools. This study argues that mobilising interpretive capital with teachers through partnerships can enhance the transformation of school grounds to foster environmental learning. It shows how attempts to find solutions with teachers were made in response to pedagogical and curriculum tensions that arise around the implementation of environmental education processes in their schools. To provide orientation in environmental education processes in schools, analyses of socially critical environmental education processes and a review of theoretical perspectives on interpretation as an environmental education process are presented. I have viewed interpretation and environmental education as reciprocally necessary aspects for enabling the development of critical environmental literacy and action competence. To explain this view, the notion of environmental interpretation and education processes has been applied and presented in this study. Finally, practical outcomes of the study on transformation of school grounds, improved education practice, enhanced professional competencies amongst teachers, new interpretive materials in schools and the establishment of partnerships are examined.
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  • Date Issued: 2003

Map of Africa, 1794

  • Subjects: Africa , Africa -- Maps
  • Language: English
  • Type: Image
  • Identifier: vital:13969 , http://hdl.handle.net/10962/d1017489 , CD 55 , MS 10 542 , PIC/SL 4804
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A short composition portfolio

Effect of adding a probiotic to an aquaponic system on plant and fish growth, water quality, and microbial diversity

  • Authors: Kasozi, Nasser
  • Date: 2022-04-08
  • Subjects: To be added
  • Language: English
  • Type: thesis , text , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/294596 , vital:57236
  • Description: Thesis embargoed. Release date April 2023. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
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  • Date Issued: 2022-04-08

Polyunsaturated fatty acid metabolism and effects on colon cancer cell biology in vitro.

  • Authors: Bulcao, Candice
  • Date: 2013
  • Subjects: Unsaturated fatty acids , Unsaturated fatty acids in human nutrition , Colon (Anatomy)-- Cancer , Cancer -- Nutritional aspects
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4137 , http://hdl.handle.net/10962/d1016128
  • Description: Colon cancer is a leading cause of cancer related deaths worldwide. Lifestyle factors such as diet and exercise have been implicated as important agents in colon cancer development and progression. Epidemiological, in vivo and in vitro studies have found that n-3 polyunsaturated fatty acids (PUFAs) reduce colon carcinoma. The role of n-6 PUFAs remains a controversial topic, with studies indicating both promoting and preventing capabilities published. In order to better understand the effects of PUFAs on colon carcinoma, it is important to have an understanding of how they will be broken down in the body. During this study, in silico metabolism of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA) predicted the formation of hydroxy-, di-hydroxy- and epoxy-FAs. A gas chromatography-mass spectrometry method was developed and validated for the detection of these PUFAs and their cytochrome P450 (CYP) metabolites. A human liver microsomal system for the in vitro metabolism of EPA, DHA and AA was optimised in terms of microsomal and PUFA concentration. The system resulted in the metabolism of the positive control, lauric acid, to 12-hydroxy-lauric acid but was unable to metabolise the PUFAs of interest. EPA, DHA and AA reduced cell viability in the colon carcinoma cell lines SW480 and SW620 in the micromolar concentration range (25 – 200 μM). The CYP epoxidation metabolite of EPA, 17, 18-epoxyeicosatetraenoic acid (17, 18-EpETE) resulted in a significant reduction in SW480 cell viability relative to the parent compound at lower concentrations (25 and 50 μM). Annexin V apoptosis analysis revealed that EPA and 17, 18- EpETE did not result in apoptosis in SW480 cells at a concentration of 25 μM and over an incubation period of 24 hours. A significant reduction in reactive oxygen species production was seen in SW480 cells after incubation with 25 μM 17, 18-EpETE for 24 hours. EPA and 17, 18-EpETE were implicated in the reduction of colon cancer metastasis since they were able to reduce SW480 migration and anchorage independent cell growth. These results indicate that the dietary intake of EPA, DHA and AA may be beneficial to one’s health due to the negative effects that these PUFAs had on colon carcinoma. Future studies are needed to confirm these benefits and compare the effects of the PUFAs to their CYP-metabolites.
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  • Date Issued: 2013

A consideration of the relations between Church and industry

  • Authors: Hulley, L D
  • Date: 1968
  • Subjects: Industries -- Religious aspects , Church and industry , Christian life
  • Language: English
  • Type: Thesis , Bachelor , BDiv
  • Identifier: vital:1295 , http://hdl.handle.net/10962/d1015396
  • Description: [From Chapter 1]. The first point I wish to make, in fact it can be considered the primary one in this essay for what is to follow is a response to it, is that theology must be responding theology. This is a theology which takes the world seriously and responds to it in a Christian way. This is the approach we find in the New Testament: particularly in the Epistles, concrete problems and behaviour in the lives of his converts to which St. Paul responded prompted the didactic sections of his epistles. J. G. Davies supports this view in Planning for Mission "There are ... two primary realities'' he says "with which the congregation must be concerned: The Gospel of God and the world to which it is sent. 'Authentic theology' emerges out of the dialogue between the Gospel and the world." This is what Tillich calls the method of correlation. First we make an analysis of our situation and then try to relate the Christian message to the problems within it. While this compels us to rethink and reformulate many traditional Christian views, nothing "can change the substance of ... the ... answer, because this is the logos of being, manifest in Jesus as the Christ." This does not say that "we have all the answers" (in fact it will become clear that we do not), but it does express our conviction that the Christian Gospel has to do with life in all its aspects.
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  • Date Issued: 1968

Movement patterns, stock delineation and conservation of an overexploited fishery species, Lithognathus Lithognathus (Pisces: Sparidae)

  • Authors: Bennett, Rhett Hamilton
  • Date: 2012
  • Subjects: Reef fishes -- Behavior , Endangered species -- South Africa , Fish stock assessment -- South Africa , Fishery management -- South Africa , Fish communities -- South Africa , Sparidae , Lithognathus , Lithognathus -- Growth
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5374 , http://hdl.handle.net/10962/d1015709
  • Description: White steenbras Lithognathus lithognathus (Pisces: Sparidae) has been a major target species of numerous fisheries in South Africa, since the late 19th century. Historically, it contributed substantially to annual catches in commercial net fisheries, and became dominant in recreational shore catches in the latter half of the 20th century. However, overexploitation in both sectors resulted in severe declines in abundance. The ultimate collapse of the stock by the end of the last century, and the failure of traditional management measures to protect the species indicate that a new management approach for this species is necessary. The species was identified as a priority for research, management and conservation in a National Linefish Status Report. Despite knowledge on aspects of its biology and life history, little is known about juvenile habitat use patterns, home range dynamics and movement behaviour in estuaries. Similarly, the movement and migration of larger juveniles and adults in the marine environment are poorly understood. Furthermore, there is a complete lack of information on its genetic stock structure. Such information is essential for effective management of a fishery species. This thesis aimed to address the gaps in the understanding of white steenbras movement patterns and genetic stock structure, and provide an assessment of its current conservation status. The study adopted a multidisciplinary approach, incorporating a range of methods and drawing on available information, including published literature, unpublished reports and data from long-term monitoring programmes. Acoustic telemetry, conducted in a range of estuaries, showed high site fidelity, restricted area use, small home ranges relative to the size of the estuary, and a high level of residency within estuaries at the early juvenile life stage. Behaviour within estuaries was dominated by station-keeping, superimposed by a strong diel behaviour, presumably based on feeding and/or predator avoidance, with individuals entering the shallow littoral zone at night to feed, and seeking refuge in the deeper channel areas during the daytime. Conventional dart tagging and recapture data from four ongoing, long-term coastal fish tagging projects, spread throughout the distribution of this species, indicated high levels of residency in the surf zone at the late juvenile and sub-adult life stages. Consequently, juvenile and sub-adult white steenbras are vulnerable to localised depletion, although they can be effectively protected by suitably positioned estuarine protected areas (EPAs) and marine protected areas (MPAs), respectively. It has been hypothesized that adult white steenbras undertake large-scale coastal migrations between summer aggregation areas and winter spawning grounds. The scale of observed coastal movements was correlated with fish size (and age), with larger fish undertaking considerably longer-distance coastal movements than smaller individuals, supporting this hypothesis. Given the migratory behaviour of adults, and indications that limited spawning habitat exists, MPAs designed to protect white steenbras during the adult life stage should encompass all known spawning aggregation sites. The fishery is plagued by problems such as low compliance and low enforcement capacity, and alternative management measures, such as seasonal closure, need to be evaluated. Despite considerable conventional dart tagging effort around the coastline (5 782 fish tagged) with 292 recaptures there remains a lack of empirical evidence of fish migrating long distances (> 600 km) between aggregation and spawning areas. This uncertainty in the level of connectivity among coastal regions was addressed using mitochondrial DNA sequencing and genotyping of microsatellite repeat loci in the nuclear genome, which showed no evidence of major geographic barriers to gene flow in this species. Samples collected throughout the white steenbras core distribution showed high genetic diversity, low genetic differentiation and no evidence of isolation by distance or localised spawning. Although historically dominant in several fisheries, analysis of long-term commercial and recreational catch data for white steenbras indicated considerable declines and ultimately stock collapse. Improved catch-per-unit-effort in two large MPAs subsequent to closure confirmed that MPAs can be effective for the protection of white steenbras. However, the current MPA network encompasses a low proportion of sandy shoreline, for which white steenbras exhibits an affinity. Many MPAs do not prohibit recreational shore angling, which currently accounts for the greatest proportion of the total annual catch. Furthermore, EPAs within the juvenile distribution protect a negligible proportion of the total available surface area of estuaries – habitat on which white steenbras is wholly dependent. Despite some evidence of recent increases in abundance in estuaries and the surf zone in certain areas, white steenbras meets the criteria for “Endangered” on the IUCN Red List of Threatened Species, and for “Protected species” status on the National Environmental Management: Biodiversity Act of South Africa. The species requires improved management, with consideration for its life-history style, estuarine dependency, surf zone residency, predictable spawning migrations and its poor conservation status. The multidisciplinary approach provides valuable information towards an improved scientific basis for the management of white steenbras and a framework for research that can be adopted for other overexploited, estuarine-associated coastal fishery species.
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  • Date Issued: 2012

The modification of a computer simulation for use in the professional training of South African secondary school teachers with specific reference to the probationary year

  • Authors: Marsh, Cecille Joan Anna
  • Date: 1989
  • Subjects: Computer simulations , High school teachers , Teacher training
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1376 , http://hdl.handle.net/10962/d1001442
  • Description: The topic of this thesis arose out of a desire to meet the need for a practical means of supplementing the preparation of Higher Diploma of Education (H.D.E.) students for their future role as first-year teachers. It was established that this need was not adequately filled by conventional university teacher-training methods. The literature about computerised simulation of role-playing and teaching activities was investigated and the investigation indicated that such simulations had been relatively successful. A published American computer simulation, TENURE, in which the student plays the role of a first-year teacher, was selected for modification to meet the needs of South African students. This program is implemented in the TUTOR computer language and runs on the Control Data South Africa PLATO system. In order to determine the needs of South African students, two groups of Rhodes University students worked through the simulation as it was being modified. The modifications were adapted according to the students' responses to a questionnaire. The simulation has been tested by 72 H.D.E. students and several educationists and the response has been positive
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  • Date Issued: 1989
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