Aspects of condition in captive and free-ranging dolphins
- Authors: Young, Deborah Dione
- Date: 1999
- Subjects: Dolphins -- Physiology Dolphins -- Behavior
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5799 , http://hdl.handle.net/10962/d1006117
- Description: Aspects of morphological and physiological condition of captive and net-caught dolphins were studied with respect to age, diet, reproduction and seasonal changes in environmental factors. These investigations aimed to provide base-line data on marine mammal physiological and morphological condition indices and to expand the knowledge of condition assessment of small cetaceans. By examining the interactive nature of animal condition and growth, diet and the environment, the study investigated the potential usefulness of animal condition indices to assess and monitor habitat quality. Base-line values for haematological and blood chemistry parameters were established for five captive bottlenose dolphins (Tursiops truncatus), using monthly blood samples, collected between 1992 and 1995, and corresponding measures of body weight and blubber thickness; feeding, dietary energy intake, water temperature and behavioural and medical records. Curves of best fit were used to interpret trends between leukocytic, haematological and blood chemistry parameters and morphology, diet and water temperature. WBC's and WBC differential cell types were related more distinctly to clinical changes in health, than to condition. RBC, HB and PCV were useful as short-term indicators of nutritional condition, with enhanced haematological status associated with greater food intake and improved diet quality. Weight was a more effective long-term indicator of nutritional status. The importance of blubber thickness measurements as a morphological index of condition was reinforced, with relationships between blubber thickness and haematology highlighting interactions between morphological and physiological condition. The complex interactions between haematology, diet, temperature and weight emphasised the need to account for all influential factors when considering haematological condition. The blood chemistry parameters of serum creatinine, BUN, BUN:creatinine and serum albumin provided the best indication of nutritional condition and diet quality in captive dolphins. Creatinine and BUN:creatinine also reflected changes in morphological condition. Reduced ALP was associated with nutritional stress but was more effectively used as an indication of metabolism and growth activity. LDH and CPK were highly variable and fluctuated with changing activity levels, limiting their use as condition indices. Serum sodium was an important indication of diet quality and hydration status. Many of these parameters effectively illustrated that physiological condition is compromised outside of the thermoneutral zone of the species. Bottlenose and common (Delphinus delphis) dolphins, incidentally caught in shark nets, were used to investigate the condition of free-ranging dolphins. Blood samples, taken as soon as possible after capture from drowned animals, were used to analyse physiological parameters. Dissections provided morphological data. Age and dietary status were assessed using growth layer groups in teeth and stomach content analyses, respectively. Morphological measures of net-caught dolphins reflected important interactions with diet, water temperature and reproductive status. Weight, girth and blubber thickness were valuable indicators of condition, although blubber thickness and proportional blubber weight were the best indicators of nutritional status. Condition of net-caught dolphins was difficult to assess in terms of leukocytic and haematological parameters. Stress- and post-mortem-associated changes, and variable data, reduced the usefulness of some parameters. WBC counts reflected on immunological status and served to emphasise changes in health, which may lead to deterioration in condition. WBC's showed potential as indicators of habitat quality, in terms of parasite load and/or pollution. Interactions between RBC, HB, PCV, MCV and dietary, morphological and environmental factors proved valuable in the short-term. Several haematological parameters were related to morphological condition, with weight, girth and blubber thickness, showing potential as non-invasive predictors of haematological status. Relationships between haematology and water temperature implied that dolphins have physiological and environmental "zones of comfort", within which condition is optimised. LDH and CPK were elevated by capture stress and post-mortem changes. Serum sodium and plasma glucose were good indicators of short-term nutritional status, but were altered by stress, which reduced their usefulness as condition indicators. BUN, albumin, globulin, albumin:globulin, total cholesterol and triglycerides appeared to be little affected by these changes and are potentially valuable indicators of condition in net-caught and/or free-ranging dolphins, particularly with respect to nutritional condition, and associated changes in morphology. Although data were limited, these parameters show the greatest potential as physiological indicators of animal condition and environmental health. The limitations of this study are recognised, however, results highlight the feasibility of using net-caught specimens to monitor the condition of free-ranging marine mammals, and the marine habitat as a whole. Relationships established in this study will be used to elucidate further on the interactive nature of marine mammal condition and aid in the development of a non-invasive condition assessment technique.
- Full Text:
- Date Issued: 1999
A study of the personal literature written in the Eastern Cape in the nineteenth century
- Authors: Young, Cheryl Ann
- Date: 1995
- Subjects: Arkwright, Robert Wigram, 1822 -- Diaries , Armstrong, Frances -- Diaries , Bowker, Thomas Holden, 1807-1885 -- Diaries , Brownlee, James, 1824-1851 -- Diaries , Crealock, John North, 1837-1895 -- Diaries , Flanagan, Arthur Stephen -- Diaries , Hall, Henry, 1815 -- Diaries , Merriman, Nathaniel James, 1809-1881 Diaries , Pigot, Sophia, 1804-1881 -- Diaries , Stretch, Charles Lennox, 1797-1882 -- Diaries , Griffith, Patrick Raymond -- Diaries , Clergy -- South Africa -- Diaries , Diaries -- History and criticism , Soldiers -- South Africa -- Diaries , South African diaries -- History and criticism , Women -- South Africa -- Diaries
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2231 , http://hdl.handle.net/10962/d1002274 , Arkwright, Robert Wigram, 1822 -- Diaries , Armstrong, Frances -- Diaries , Bowker, Thomas Holden, 1807-1885 -- Diaries , Brownlee, James, 1824-1851 -- Diaries , Crealock, John North, 1837-1895 -- Diaries , Flanagan, Arthur Stephen -- Diaries , Hall, Henry, 1815 -- Diaries , Merriman, Nathaniel James, 1809-1881 Diaries , Pigot, Sophia, 1804-1881 -- Diaries , Stretch, Charles Lennox, 1797-1882 -- Diaries , Griffith, Patrick Raymond -- Diaries , Clergy -- South Africa -- Diaries , Diaries -- History and criticism , Soldiers -- South Africa -- Diaries , South African diaries -- History and criticism , Women -- South Africa -- Diaries
- Description: The evidence of these diaries, all written in the nineteenth century, reveals the heterogeneous nature of early settler society in the Eastern Cape. Generalizations can only be of the most tenuous kind in such a small sample; but women tend to dwell on the domestic, the men on their public lives, the most reticent about their private lives are the soldiers. There is one diary which can be described as personal; the diarists did not regard their diaries as appropriate repositories of their personal triumphs and failures. The perceptions formed in Britain about the land and people of Africa are not drastically modified upon arrival unless the diarist experiences a prolongued contact with either.
- Full Text:
- Date Issued: 1995
Adaptation of the mathematics recovery programme to facilitate progression in the early arithmetic strategies of Grade 2 learners in Zambia
- Authors: Young, Catherine
- Date: 2017
- Subjects: Mathematics -- Study and teaching (Elementary) -- Zambia Arithmetic -- Study and teaching (Elementary) -- Zambia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/4977 , vital:20749
- Description: Research indicates that many children finish primary school in Southern Africa still reliant on inefficient counting strategies. This study extends the research of the South African Numeracy Chair project to early mathematics intervention with Grade 2 learners. It investigated the possible adaptation of the Mathematics Recovery programme to facilitate learner progression in early arithmetic strategies. This study aimed to investigate the possibility of adapting the Mathematics Recovery programme for use in a whole class setting, and to research the effectiveness of such an adapted programme. This study also aimed to investigate the extent of the phenomenon of unit counting and other early arithmetic strategies used in the early years in Zambia. This study was conducted from an emergent perspective. A review of the literature indicated that children who become stuck using unit counting face later mathematical difficulties, and that teacher over-emphasis on unit counting in the early years of schooling may be a contributing factor. This study used a qualitative design research methodology that consisted of a preparation phase, teaching experiment and retrospective analysis. The context of this teaching experiment was a seven week after-school intervention with a class of Grade 2 learners aged seven to eight in a rural Zambian primary school. Data collection and analysis focused on video recordings of a sample of 6 learners. The experimental teaching content focused on the Early Arithmetic Strategies aspect of the Mathematics Recovery programme. Although limited by time and research focus, this study found that all learners made some progress in early arithmetic strategies, and indicates that the Mathematics Recovery programme has potential for adaptation for early intervention in whole class teaching to address the mathematical education challenges in Zambia and beyond. This study also found that unit counting predominated in the sample learners, but that strategies were not yet entrenched, indicating this was a suitable age for early intervention. This study makes methodological contributions to a growing body of research into the adaptation of the Mathematics Recovery in Southern African contexts and suggests avenues for possible further research.
- Full Text:
- Date Issued: 2017
The economic geography of the Union's chicory Industry : past and present
- Authors: Young, Bruce Stratton
- Date: 1959
- Subjects: Chicory -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4882 , http://hdl.handle.net/10962/d1013438
- Description: The motivating force behind this survey and study of a branch of the Union's agricultural industry has been the conviction that detailed case studies of economic activities and their influences on the map of the country are the essential foundation stones on which mature scholars may build a perceptive and valuable economic geography of the Union.
- Full Text:
- Date Issued: 1959
Marine plastic pollution impacts on ecosystem services and livelihoods in South Africa: a review and stakeholder perceptions
- Authors: Yose, Papama
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424743 , vital:72180
- Description: Marine plastic pollution is one of the major environmental problems globally, with adverse impacts on marine ecosystem services, functions and benefits and people. Yet, compared to plastic pollution impacts on terrestrial ecosystems, the impacts of plastic waste on marine ecosystems are little studied and poorly understood in South Africa. In response, research interest on the ecological and economic impacts of marine plastic pollution has grown rapidly but socio-cultural impacts remain poorly conceptualized and little understudied. This trend is arguably driven by the dominance of a quantitative paradigm which is arguably inadequate to respond to dynamic socio-cultural issues and contexts. Further, in South Africa, marine ecosystems are used by diverse groups of people ranging from subsistence users, tourism operators, commercial fishers and recreational users, meaning that addressing marine plastic pollution requires a multi-stakeholder approach. However, few studies explore the perceptions of diverse stakeholders regarding marine plastic pollution, its impacts and potential interventions. Against this background, the objective of the thesis are twofold: (a) to argue for a more nuanced understanding of marine plastic pollution impacts on human well-being in order to strengthen conceptualization of impacts that goes beyond direct and quantitatively measured impacts (ecological, health and economic) but considers the socio-cultural dimensions of impacts (lifestyle disruptions, mental health costs and cultural and heritage impacts), and (b) examine stakeholders’ perceptions of marine plastic pollution, its impacts and potential interventions in South Africa. Drawing on case studies, this study provides a working definition of the socio-cultural impacts of marine plastic pollution and a conceptual framework for categorizing the impacts. It highlights three dimensions of the socio-cultural impacts of marine plastic pollution (lifestyle, mental health, and cultural and heritage impacts). It also illustrates connections between marine ecosystems and marine-based livelihood activities with the social and cultural dimensions of human wellbeing to show the links between marine environments and socio-cultural contexts. Concerning stakeholder perceptions, the study showed a tendency to associate marine plastic pollution with immediate, noticeable and easily quantifiable ecological impacts such as entanglement and ingestion of marine organisms, economic impacts and social impacts (e.g., loss of aesthetic appeal). However, secondary impacts such as loss of marine biodiversity and social impacts such as human health, were largely unknown. Moreover, there was heterogeneity in perceptions of marine plastic pollution impacts among the stakeholder groups. Prospective studies researching marine plastic pollution impacts should consider divergent and diverse perceptions of different stakeholders to capture the real costs of marine plastic pollution. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2023
- Full Text:
- Date Issued: 2023-10-13
The relationship between leadership and employee work performance in a Nigerian courier company
- Authors: Yobe, Kingsley
- Date: 2013
- Subjects: Leadership -- Nigeria Transformational leadership -- Nigeria Industrial management -- Nigeria Business planning -- Research -- Nigeria Employees -- Rating of -- Nigeria Organizational change
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:805 , http://hdl.handle.net/10962/d1006858
- Description: A number of authors have portrayed leadership as a vital factor in the success or failure of an organization. Hence Bass (1994; 1997) believes that excellent organizations begin with excellent leadership and organisations reflect their leadership (Maritz, 1995). Therefore, successful organisations reflect their leadership (Maritz, 1995). In an attempt to investigate the aim of this research, various performance and leadership concepts and theories were investigated: the trait concept, behavioural approaches and situational/contingency approaches. Every one of these theories gave a different explanation to leadership. Furthermore, transactional, and transformational leadership were also discussed. The difference between these two models according to Bass and Avolio (1994) is that the work performance of the followers of transformational leadership is usually beyond expectations, while transactional leadership, at best, leads to expected performance. In terms of performance, it is argued that employee work performance can lead to a successful organisational performance. This is because several organisations attribute their business success to the work performance of their employees. According to Collis and Montgomery (1995) employee work performance has a major positive influence on organisational performance. Nevertheless, the accomplishment of an organisation is dependent on the leader’s ability to enhance human resources; hence “effective organisations require effective leadership” (Maritz, 1995). Transformational leadership was identified as the effective leadership style that can motivate workers to improve on their performance by instilling trust and confidence in them. Transformational leadership is superior to both transactional and non-transactional leadership because it makes workers loyal to the mission and vision of their organizations. Bass (1990) states “that the leadership research over the years has proved that loyalty is more powerful than tangible inducements.” Furthermore, non- transactional leaders avoid decision making, allowing their subordinates to take charge of the work process (Bass 1990). This research focuses on the relationship between leadership and employee work performance in a Nigerian Courier Company. In addressing this aim, a Nigerian Courier company was selected as the research context because of its success in the Nigerian turbulent business environment that is plagued by the country’s economic, social, and political troubles (McKern, Meza, Osayande and Denend, 2010). The research hypothesis of this research was generated to investigate leadership and employee performance. Leadership and performance were also identified as the research independent and dependent variables. Thus the research hypotheses were as follows: Hypothesis 1. Null Hypothesis: There is no significant positive linear relationship between employee performance and transformational leadership Alternative Hypothesis: There is significant positive linear relationship between employee performance and transformational leadership Hypothesis 2. Null Hypothesis: There is no significant positive linear relationship between employee performance and transactional leadership Alternative Hypothesis: There is significant positive linear relationship between employee performance and transactional leadership Hypothesis 3. Null Hypothesis: There is no significant positive linear relationship between employee performance and non-transactional leadership. Alternative Hypothesis: There is significant positive linear relationship between employee performance and non-transactional leadership. The general methodology included the use of a valid and reliable instrument known as the Multifactor Leadership Questionnaire (MLQ) and the company’s performance appraisal process. These instruments were used to collect information about employee work performance. The validity and reliability of the MLQ is not in doubt because it was formulated from the full range leadership development theory of Bass and Avolio (1997) and has been used extensively worldwide (Bass and Avolio, 1997). The research data was analysed using Statistica (StatSoft, 2011). Once the data was imported the necessary leadership factors were calculated as per the MLQ scoring key. From the eight factors a further three factors were generated namely transformational, transactional and nontransactional leadership. The data was checked and described using frequency tables and descriptive statistics, followed by correlation matrices coupled with their corresponding scatter plots. The research data was tested for consistency and reliability. Sekaran (2000) states that in order to determine the reliability of a measure one needs to test for both consistency and stability. For this research, linear correlation and regression analysis was used. The outcome of the first investigated hypothesis confirmed that there is a strong significant, positive linear relationship between employee performance and transformational leadership (ρ<0.0001). However, the findings on the null hypothesis, states that transformational leadership has no significant positive linear relationship with employee performance. The null hypothesis is REJECTED, because the model is significant at ρ<.0001. Thus, the alternative hypothesis is ACCEPTED because it concludes that there is sufficient evidence, at the 5% level of significance, that there is significant positive linear relationship between employee performance and transformational leadership. The second hypotheses found that with 5% level of significance there is no significant positive linear relationship between transactional leadership and employee performance (ρ =0.317). It must be noted that since the correlation is not significant the null hypothesis which states that there is no significant positive linear relationship between employee performance and transactional leadership was NOT REJECTED. The outcome of the third hypotheses support the null hypothesis, because the negative linear relationship between employee performance and non-transactional leadership is not significant (ρ = 0.6718). This informed the conclusion that at the 5% level of significance, there is no positive linear relationship between non-transactional leadership and employee performance. The findings of this research favour the conclusion drawn by Brand, Heyl and Maritz (2000) that suggested a more significant relationship between transformational leadership and employee performance, than any other leadership style. Evidence put together in the retail and manufacturing sector of South Africa, and the armed forces of the United States of America, Germany and Canada, point in the direction of the strong, positive effects of transformational leaders (Brand, et al., 2000). Again the effectiveness of transformational leadership can be reinforced by the research directed by Ristow, Amos and Staude (1999), which resolved that the effectiveness of transformational leadership was greater in a South African cricketing environment. Hayward, Davidson, Pascoe, Tasker, Amos and Pearse (2003) conducted research in a pharmaceutical organisation and found a positive linear relationship between transformational leadership and employee work performance. These research outcomes clarify the investigation by Pruijn and Boucher (1994) which established “that transformational leadership is an extension of transactional leadership” (Bass, 1997). The difference between these two models according to Bass and Avolio (1994) is that the work performance of supporters of transformational leadership is usually beyond expectation, while the behaviour of the supporters of transactional leadership, at best, leads to anticipated work performance. This research will be used to improve the relationship between the leaders and employees of the courier company under investigation. It will be useful for the placement of individuals to leadership positions in the company. It will also impact on how future leadership training will be conducted by the company, and of course add to the body of knowledge. This is supported by research conducted in the service sector which states that “transformational leadership affects performance over and above transactional leadership” (Geyery and Steyrer, 1998).
- Full Text:
- Date Issued: 2013
Learning about volunteering: an exploration of literacy volunteers' experiences
- Authors: Yendall, Kaitlin Amy
- Date: 2020
- Subjects: Literacy -- Study and teaching -- South Africa , Literacy programs -- South Africa , Voluntarism -- South Africa , Volunteer workers in community development -- Training of , Service learning , Language and education -- South Africa , Language arts (Primary) , English language -- Study and teaching (Elementary) , Volunteer workers in Education -- Training of
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/138336 , vital:37623
- Description: After almost 25 years of democracy in South Africa, not everyone has access to the same quality education. The responsibility of creating a literate society however cannot rely on the national government and schools alone, but instead needs to fall on the shoulders of various stakeholders. Volunteers in particular have an important role to play in remedying the current literacy crisis experienced in South Africa. This study takes the form of a case study approach and examines the experiences of Project Read literacy volunteers. A telephonic survey and two focus group discussions were conducted in order to determine who it is that volunteers for the programme; what prompts these particular individuals to volunteer; the perceived benefits of volunteering; and how volunteers report on their volunteering experiences. Although the Project Read programme is focused on the early literacy development of learners, volunteers seemed to undergo a developmental process themselves – something they had not anticipated at the start of their volunteering journey. This study illustrates the power of meaningful relationships in breaking down artificial categories and in bringing about important change with regards to the perceptions and attitudes of individuals towards community engagement. It is hoped that the data generated through this study will assist in recruiting and retaining more literacy volunteers through feedback to the NGO. In this way more children will be assisted to enhance their literacy competencies, from which they can build and achieve.
- Full Text:
- Date Issued: 2020
Healing at the margins: discourses of culture and illness in psychiatrists', psychologists' and indigenous healers' talk about collaboration
- Authors: Yen, Jeffery
- Date: 2000
- Subjects: Traditional medicine -- South Africa , Medical policy -- South Africa , Mental health -- South Africa , Healers -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3090 , http://hdl.handle.net/10962/d1002600 , Traditional medicine -- South Africa , Medical policy -- South Africa , Mental health -- South Africa , Healers -- South Africa
- Description: This dissertation explores discourses about culture and illness in the talk of mental health professionals and indigenous healers. It represents an attempt to situate the issue of indigenous healing in South Africa within a particular strand of critical discourse analytic research. In the context of current deliberations on the value, or otherwise, of indigenous healing in a changing health and specifically mental health system, the talk of both mental health practitioners and indigenous healers as they conceptualise “disorder”, and discuss possibilities for collaboration, is chosen as a specific focus for this study. Disputes over what constitutes “disorder” both within mental health, and between mental health and indigenous healing are an important site in which the negotiation of power relations between mental health professionals and indigenous healers is played out. The results of this study suggest that despite the construction of cogent commendations for the inclusion of indigenous healing in mental health, it remains largely marginalised within talk about mental health practice. While this study reproduces to some extent the marginalisation of indigenous healing discourse, it also examines some of the discursive practices and methodological difficulties implicated in its marginalisation. However, in the context of “cultural pride strategies” associated with talk about an African Renaissance, indigenous healing may also function as a site of assertion of African power and resistance in its construction as an essentially African enterprise. At the same time, it may achieve disciplinary effects consonant with cultural pride strategies, in constructing afflictions in terms of neglect of, or disloyalty to cultural tradition. These results are discussed in terms of the methodological difficulties associated with interviewing and discourse analysis of translated texts, which contributes to difficulties with articulating indigenous healing discourse in a way that challenges the dominant psychiatric discourses implicated in its marginalisation within mental health. It concludes with recommendations for future research which addresses indigenous healing discourse in its own terms, and examines its operation as a disciplinary apparatus in South African society.
- Full Text:
- Date Issued: 2000
The representation of women's reproductive rights in the American feminist blogosphere: an analysis of the debate around women's reproductive rights and abortion legislation in response to the reformation of the United States health care system in 2009/10
- Authors: Yelverton, Brittany
- Date: 2010
- Subjects: Abortion -- Law and legislation -- United States Reproductive rights -- Law and legislation -- United States Fertility -- Law and legislation -- United States Feminism Blogs -- United States Health care reform -- United States -- 21st century Women -- Blogs -- United States Social change -- United States Discourse analysis Feministing Jezebel
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3494 , http://hdl.handle.net/10962/d1002949
- Description: This study investigates the representation of women's reproductive rights in the feminist blogopshere during 2009/10 United States health care reform. Focusing on two purposively selected feminist blogsites - Feministing and Jezebel- it critically examines the discursive and rhetorical strategies employed by feminist bloggers to contest the erosion of women's reproductive rights as proposed in health care reform legislation. While the reformation of the U.S. health care system was a lengthy process, my analysis is confined to feminist blog posts published in November 2009, December 2009 and March 2010. These three months have been designated as they are roughly representative of three pivotal stages in health care reform: the drafting of the House of Representatives health care reform bill and Stupak Amendment in November 2009, the creation of the Senate health care bill inclusive of the Nelson compromise in December 2009, and the passage of the finalised health care reform bill, the Patient Protection and Affordable Care Act and supplementary executive order, in March 2010. This study is informed by feminist poststructuralist theory and Foucault's conceptions of discourse and power - an appropriate framework for identifying and analysing the unequal power relations that exist between men and women in patriarchal societies. Foucault conceives of discourse as both socially constituted and constitutive and contends that through the constitution of knowledge, discourses designate acceptable ways of talking, writing, and behaving, while simultaneously restricting and prohibiting alternatives, thereby granting power and authority to specific discourses. However, Foucault also stresses the multi-directionality of power and asserts that though hegemonic discourses are privileged over others, power lays in discursive practice at all social sites; hence the socially and politically transformative power of contesting discourses. Critical discourse analysis is informed by this critical theory of language and regards the use of language as a form of social practice located within its specific historical context. Therefore, it is through engaging in the struggle over meaning and producing different 'truths' through the reappropriation of language that the possibility of social change exists. Employing narrative, linguistic and rhetorical analysis, this study identifies the discursive strategies and tactics utilised by feminist bloggers to combat and contest anti-choice health care legislation. The study further seeks to determine how arguments supportive of women's reproductive rights are framed and how feminist discourses are privileged while patriarchal discourse is contested. Drawing on public sphere theory, I argue that the feminist blogosphere constitutes a counter-public which facili tates the articulation and circulation of marginalised and counter-discourses. I conclude this study by examining the feminist blogopshere's role in promoting political change and transformation through alternative representations of women and their reproductive rights.
- Full Text:
- Date Issued: 2010
Native-range studies on insect herbivores associated with African Lovegrass (Eragrostis curvula) in South Africa: prospects for biological control in Australia
- Authors: Yell, Liam Dougal
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424446 , vital:72154
- Description: Eragrostis curvula (Schrad.) Nees. (African Lovegrass) is an African native species of grass that was intentionally introduced for pasture in Australia. It has since escaped cultivation and has become widespread and highly invasive. Eragrostis curvula has been recorded in every state and territory in Australia where it has altered fire regimes, disrupted nutrient cycles and can reduce livestock carrying capacity by up to 50%. The Centre for Biological Control at Rhodes University and the New South Wales Department of Primary Industries have been working in collaboration to identify and screen herbivorous insects as biological control agents for E. curvula in Australia. Native-range surveys were conducted between 2021 and 2022 on E. curvula at twenty-two sites across South Africa to identify herbivorous natural enemies associated with it. Species accumulation curves were generated to ensure adequate sampling was performed to identify all the insects associated with E. curvula. Twenty-nine non-target grass species were surveyed simultaneously to determine the field-host range of the natural enemies associated with the target weed. Herbivorous natural enemies were prioritised as possible biological control agents against E. curvula in Australia based on field-host range, predicted efficacy and climatic suitability. Four insect species were consistently found on E. curvula, two of which were herbivorous, as well as a parasitoid and a detritivore. Species accumulation curves show that the insect community was adequately sampled in South Africa. The two herbivorous insects were identified to the lowest taxonomic level using COI barcoding. Both species are undescribed phytophagous wasps in the genus Tetramesa (Hymenoptera: Eurytomidae). Because Tetramesa species have been shown to be host specific and highly damaging in previous biological control programs for other invasive grass weeds, we assessed their suitability as candidate biological control agents for use on E. curvula in Australia. Both Tetramesa species (“sp. 4” and “sp. 5”) were found on several native congeners under field conditions in South Africa. Congeneric South African-native non-target grass species were used as phylogenetic proxies to assess the risk posed to Australian native Eragrostis species. This highlighted three non-target Australian native Eragrostis species, namely: E. parviflora (R. Br.) Trin., E. leptocarpa Benth. fl., and E. trachycarpa Benth., that are at risk of being attacked by the two candidate agents based on their phylogenetic proximity to E. curvula. Predicted efficacy trials were conducted at five long-term repeat survey sites and revealed that Tetramesa sp. 4 does not reduce the probability of E. curvula tiller survival or reproduction, while Tetramesa sp. 5 does not reduce the probability of tiller reproduction but does increase the probability of tiller survival. This result was unexpected and may be a plant compensatory response to herbivory. The sites where both Tetramesa species were collected in South Africa are climatically similar to the invaded range of E. curvula in Australia, and as such, the Tetramesa spp. are likely to be suitably adapted to the climate where they would be released in Australia. These results suggest that both Tetramesa species associated with E. curvula may have too broad a host range to be used as biological control agents in Australia. However, further quarantine-based host-range assessments on Australian native Eragrostis species are recommended to confirm this. The field-based methods used in this study have reduced the number of insect and plant species that host-range assessments will be required to be performed on, thus preventing wasted resources. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2023
- Full Text:
- Date Issued: 2023-10-13
The life and times of Kama Chungwa, 1798-1875
- Authors: Yekela, Drusilla Siziwe
- Date: 1989
- Subjects: Kama, William, 1798-1875 , Shaw, William, 1798-1872 , Methodist Church of Southern Africa -- Missions , Gqunukhwebe (African people) -- History , Wesleyville mission , Gqunukhwebe (African people) -- Kings and rulers , South Africa -- History -- Frontier Wars, 1811-1878 , South Africa -- History -- Xhosa Cattle-Killing, 1856-1857 , Converts -- South Africa , Cape of Good Hope (South Africa) -- Politics and government
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2520 , http://hdl.handle.net/10962/d1001849
- Description: Few students of History understand the derivation and/or origin of the Gqunukhwebe oath "Ndifung' uChungw' efel' ennyameni: I swear by Chungwa who is lying dead at Mnyameni (Alexandria)." A desire to eludicate this point and other related facts inspired me to undertake a close examination of the history of the Gqunukhwebe people, selecting as my main theme the life-work of Chief Kama. In the first chapter I am discussing the creation of the Gqunukhwebe Chiefdom under Khwane by the Xhosa King, Tshiwo. The central theme here is the Black-White confrontation of the 17th - 18th centuries on the Cape Eastern Frontier. As a result of the collision the Gqunukhwebe people were forced to make a home on the banks of the Thwecu River along the east coast. It was here that Kama reached early manhood. The second chapter describes the establishment of Wesleyville Missionary Station by William Shaw in 1823, the first Methodist Missionary Institution in all Xhosaland. In chapter three the discussion centers on the significance of Kama's conversion. An unforeseen outcome of his public profession of the Christian faith was that it not only stigmatized the latter religion as a force destructive of the old order in Xhosa society, but it also reshaped Kama's political image for the good of his religious life. He not only fled from the neighbourhood of his relations and sojourned in a strange land, but also reinforced the Colonial forces in the contemporary frontier struggles. His integrity, self-sacrifice and pro-Colonial inclination eventually won him Middledrift. Chapter four opens with Kama's settling in Middledrift. The theme here is two-pronged. It presents the 'Cattle-Killing' delusion as a source of new trials for the 'priest-chief', and at the same time exposes the Colonial Government's efforts to gain ascendancy above the Xhosa chiefs. Kama's land was the first testing ground in this respect, and the Chief was initially agreeable to the scheme. Chapter five alludes to instances of Chief Kama's unco-operative attitude as signs that his compromising spirit had its limits. An atmosphere of disregard towards Kama pervades the period. But the adversities that threatened to dominate his later life did not by any means shake his Christian principles and convictions. The traces of his good works may to this day be seen in Middledrift, the traditional home of the Kamas.
- Full Text:
- Date Issued: 1989
Water quality, abalone growth and the potential for integrated mariculture on a South African abalone Haliotis midae L. farm
- Authors: Yearsley, Rowan David
- Date: 2008
- Subjects: Abalones -- South Africa Abalone culture -- South Africa Abalones -- Growth Mariculture -- South Africa Water quality -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5334 , http://hdl.handle.net/10962/d1005180
- Description: Abalone Haliotis midae farming in South Africa is highly intensive, employing pump-ashore, flow-through systems. Despite the known sensitivity of abalone to water quality, there is only a rudimentary understanding of water quality dynamics on South African abalone farms and its effects on abalone production. Furthermore, the potential for reusing the relatively dilute abalone farm effluent to culture other animal species has not been investigated. This study investigated the dynamics of water quality and growth on a South African abalone farm and assessed the suitability of the effluent for the culture of silver kob Argyrosomus inodorus and bloodworm Arenicola loveni loveni. Monitoring of water quality and abalone growth in abalone tanks revealed that oxygen concentrations decreased, while H⁺ ion and free-ammonia (NH₃) concentration increased in a gradient between the inflow and outflow. Abalone growth was positively correlated with oxygen concentration and negatively correlated with free-ammonia and H⁺ ion concentration. The oxygen (O) concentration of the farm influent was dependent upon the influents’ temperature (T) and was described by the relationship O (mg L⁻¹) = 11.244 – 0.208T (r²=0.74). Linear regression analysis of data collected from abalone farm tanks revealed that the concentration of total ammonia at the outflow of abalone tanks (μg TAN L⁻¹) was dependant upon temperature (°C), flow-rate (L s⁻¹ kg⁻¹ H. midae), abalone size (g) and length of time since the tank was last cleaned (d) (n = 125, r² = 0.80). The production of total ammonia (μg TAN s⁻¹ kg⁻¹) was related to temperature, abalone size and days that the tanks remained un-cleaned (n = 125; r² = 0.81). A diurnal cycle of respiration was evident in abalone tanks with higher oxygen consumption and H+ ion production at night. The oxygen concentration of farm effluent was related to temperature, farm biomass and flow rate by means of a linear regression equation (n = 40; r² = 0.69). The results demonstrated the importance of optimising the flow-rate per unit of biomass for various temperatures and sizes of abalone. As abalone size and temperature cannot be controlled under farm conditions, the flow-rate per unit of biomass which the abalone culture system receives will determine the quality of the culture water. The specific growth rate (0.48 ± 0.01 % BW d⁻¹), mortality (1.8 ± 0.5 %), feed conversion ratio (3.0 ± 0.2) and protein efficiency ratio (1.0 ± 0.1) of silver kob kept in either abalone farm effluent or control seawater for 120 days did not differ significantly (t-test, P>0.05). A 90 day growth trial indicated that abalone farm effluent is a suitable culture medium for bloodworm. Bloodworm supplied with control seawater lost weight at 0.19 ± 0.04 % BW d-1, while those given abalone effluent grew at 0.39 ± 0.07 % BW d⁻¹. Mortality was 6 ± 3 % in effluent and 11 ± 8 % in seawater. The bloodworm were efficient at processing solid waste. Abalone farm effluent initially contained 7.7 ± 13 mg L⁻¹ more suspended solids than control seawater, which contained 3.5 ± 0.5 mg L⁻¹, but after passing through bloodworm systems the concentration in abalone effluent was reduced to only 1.4 ± 3.5 mg L⁻¹ above that in control seawater. Therefore, abalone farm effluent could be reused as a culture medium for both silver kob and bloodworm. Future work is needed to investigate aspects of the feasibility of such systems such as growth rates at different sizes and stocking densities.
- Full Text:
- Date Issued: 2008
Navigating Blackness in the African Diaspora
- Authors: Yates, Sarah
- Date: 2020
- Subjects: Ellison, Ralph. Invisible man , Everett, Percival. Erasure , Wicomb, Zoe. Playing in the light , Bulawayo, NoViolet. We need new names , Africans in literature , Race in literature , African fiction (English) -- History and criticism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145720 , vital:38461
- Description: This thesis offers a comparative reading of Ralph Ellison’s Invisible Man, Percival Everett’s Erasure, Zoë Wicomb’s Playing in the Light and NoViolet Bulawayo’s We Need New Names in order to explore the diversity of subjectivities included within the terms ‘African’ and ‘black’ and to argue for the necessity of renewed definitions of Africa(nness) and blackness which allow for diverse and fluid representations. The diverse historical and political contexts in which these novels are published, as well as the critical and theoretical discussions which surround them demonstrate an evolution in literary portrayals of identity politics. As the categories of race and nation become more fluid, so too do narrative forms. In particular, this thesis is interested in the textual strategies authors use to navigate the various ways in which depictions of blackness continue to be restricted by racism, stereotypes, and the dynamics of a global literary market. As portrayals and discussions of identity politics proliferate in popular culture, they become increasingly commodified, and therefore increasingly restricted by the market.
- Full Text:
- Date Issued: 2020
Synthesis of silver nanoparticles and their role against a thiazolekinase enzyme from Plasmodium falciparum
- Authors: Yao, Jia
- Date: 2014
- Subjects: Silver , Nanoparticles , Thiazoles , Plasmodium falciparum , Antimalarials , Malaria -- Chemotherapy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4168 , http://hdl.handle.net/10962/d1020894
- Description: Malaria, a mosquito-borne infectious disease, caused by the protozoan Plasmodium genus, is the greatest health challenges worldwide. The plasmodial vitamin B1 biosynthetic enzyme PfThzK diverges significantly, both structurally and functionally from its counterpart in higher eukaryotes, thereby making it particularly attractive as a biomedical target. In the present study, PfThzK was recombinantly produced as 6×His fusion protein in E. coli BL21, purified using nickel affinity chromatography and size exclusion chromatography resulting in 1.03% yield and specific activity 0.28 U/mg. The enzyme was found to be a monomer with a molecular mass of 34 kDa. Characterization of the PfThzK showed an optimum temperature and pH of 37°C and 7.5 respectively, and it is relatively stable (t₁/₂=2.66 h). Ag nanoparticles were synthesized by NaBH₄/tannic acid, and characterized by UV-vis spectroscopy and transmission electron microscopy. The morphologies of these Ag nanoparticles (in terms of size) synthesized by tannic acid appeared to be more controlled with the size of 7.06±2.41 nm, compared with those synthesized by NaBH₄, with the sized of 12.9±4.21 nm. The purified PfThzK was challenged with Ag NPs synthesized by tannic acid, and the results suggested that they competitively inhibited PfThzK (89 %) at low concentrations (5-10 μM) with a Ki = 6.45 μM.
- Full Text:
- Date Issued: 2014
Ubomi Sisilonda: Ingqokelela Yemibongo
- Authors: Yanta, Luvuyo Mkhululi
- Date: 2021-10-29
- Subjects: Creative writing (Higher education) South Africa , Xhosa poetry 21st century , Diaries -- Authorship , South African poetry (English) History and criticism , Xhosa poetry History and criticism , Poetry Therapeutic use
- Language: Xhosa , English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192364 , vital:45219
- Description: Esi siqingatha sethisisi yingqokelela yemibongo-ngoma eyilwe ngeenjongo zokuzama ukuveza nokupholisa isilonda esidalwe ziimeko zobom esiphila kubo singabantu, izinto endizibonileyo nendidlule kuzo. Ndibhala ndibonakalisa ubumnyama endiphile kubo, apha ndizama ukusondela ekukhanyeni. Ndiqala ngokupholisa ezam izilonda kuqala. Ulwimi endilusebenzisayo lulanda imbali yam njengomfana omnyama okhulele elokishini, ilokishi nganye inolwimi lwayo. Ndisebenzisa olu lwimi ndibalisa indlela endikhule ngayo, ndikwakhankanya nokukhula ndiqheliswa ukungathethi ngezinto nokungawavezi amanxeba entliziyo yam phambi kwabantu “ilayithi ayikhali.” Ndinomdla kubabhali ababhala ngeemeko zexesha lanamhlanje, kwiimeko eziphilwa luninzi lwabantu nesimo sentlalo jikelele. Ndisebenzise umsebenzi wababhali abafana noAyanda Billie ukujonga isingqi sobom kwimibongo yakhe njengomntu ongekho kude ngokuhlala nokufuphi ngeminyaka, ndiqwalasele imisebenzi kaS. Zotwana ukuzama ukusondeza isigama kwindlela endikhule ngayo kunye noJ.J.R Jolobe ukuqwalasela ukuba babesebenzisa obuphi ubuchule bokubhala nokupholisa izilonda zabo. Ndikwacaphule kwisimbo sokubhala esikhawulezileyo semibhalo eyenzelwe iqonga njengoko ndichithe ixesha elininzi ndidlala kwaye ndikwaqeqesha abadlali beqonga. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-10-29
Access to land as a human right the payment of just and equitable compensation for dispossessed land in South Africa
- Authors: Yanou, Michael A
- Date: 2005
- Subjects: Human rights -- South Africa , Compensation (Law) -- South Africa , Right of property -- South Africa , Land reform -- South Africa , Land tenure -- South Africa , Constitutional history -- South Africa , Restitution -- South Africa , Land tenure -- Law and legislation -- South Africa , Land reform -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3699 , http://hdl.handle.net/10962/d1003214 , Human rights -- South Africa , Compensation (Law) -- South Africa , Right of property -- South Africa , Land reform -- South Africa , Land tenure -- South Africa , Constitutional history -- South Africa , Restitution -- South Africa , Land tenure -- Law and legislation -- South Africa , Land reform -- Law and legislation -- South Africa
- Description: This thesis deals with the conceptualization of access to land by the dispossessed as a human right and commences with an account of the struggle for land between the peoples of African and European extractions in South Africa. It is observed that the latter assumed sovereignty over the ancestral lands of the former. The thesis discusses the theoretical foundation of the study and situates the topic within its conceptual parameters. The writer examines the notions of justice and equity in the context of the post apartheid constitutional mandate to redress the skewed policy of the past. It is argued that the dispossession of Africans from lands that they had possessed for thousands of years on the assumption that the land was terra nullius was profoundly iniquitous and unjust. Although the study is technically limited to dispossessions occurring on or after the 13th June 1913, it covers a fairly extensive account of dispossession predating this date. This historical analysis is imperative for two reasons. Besides supporting the writer’s contention that the limitation of restitution to land dispossessed on or after 1913 was arbitrary, it also highlights both the material and non-material cost of the devastating wars of dispossessions. The candidate comments extensively on the post apartheid constitutional property structure which was conceived as a redress to the imbalance created by dispossession. This underlying objective explains why the state’s present land policy is geared towards facilitating access to land for the landless. The thesis investigates the extent to which the present property structure which defines access to land as a human right has succeeded in achieving the stated objective. It reviews the strengths and weaknesses of the land restitution process as well as the question of the payment of just and equitable compensation for land expropriated for restitution. The latter was carefully examined because it plays a crucial role in the success or otherwise of the restitution scheme. The writer argues that the courts have, on occasions, construed just and equitable compensation generously. This approach has failed to reflect the moral component inherent in the Aristotelian corrective justice. This, in the context of South Africa, requires compensation to reflect the fact that what is being paid for is land dispossessed from the forebears of indigenous inhabitants. It seems obvious that the scales of justice are tilted heavily in favour of the propertied class whose ancestors were responsible for this dispossession. This has a ripple effect on the pace of the restitution process. It also seems to have the effect of favouring the property class at the expense of the entire restitution process. The candidate also comments on the court’s differing approaches to the interpretation of the constitutional property clause. The candidate contends that the construction of the property clause and related pieces of legislation in a manner that stresses the maintenance of a balance between private property interest and land reform is flawed. This contention is supported by the fact that these values do not have proportional worth in the present property context of South Africa. The narrow definition of “past racially discriminatory law and practices” and labour tenant as used in the relevant post apartheid land reform laws is criticized for the same reason of its uncontextual approach. A comparative appraisal of similar developments relating to property law in other societies like India and Zimbabwe has been done. The writer has treated the post reform land evictions as a form of dispossession. The candidate notes that the country should guard against allowing the disastrous developments in Zimbabwe to influence events in the country and calls for an amendment of the property clause of the constitution in response to the practical difficulties which a decade of the operation of the current constitution has revealed.
- Full Text:
- Date Issued: 2005
Studies on mixed-species colonies of honeybees, Apis cerana and Apis mellifera
- Authors: Yang, Ming-Xian
- Date: 2010
- Subjects: Bees Apis cerana Honeybee Honeybee -- Behavior Bee culture Honeybee -- Physiology Insect societies Animal communication Bees -- Nests
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5779 , http://hdl.handle.net/10962/d1005467
- Description: The honeybees Apis cerana and Apis mellifera are derived from the same ancestral base about two million years ago. With speciation and evolution, they have acquired many advanced living skills in common, but have also evolved very different living strategies due to different distributions. This thesis is an intensive study of the biology of the mixed-species colonies of these species, the aims of which were to investigate their behavioural relationships and uncover the evolutionary conserved features of their behaviours subsequent to speciation. The results show that the two species can form a stable society to perform normal tasks. First, workers of both species in the mixed-colonies could form the typical retinue behaviour to hetero-species queens, thus indicating that queen pheromones could be spread to and by both species. Secondly, both species did not show significantly different ovarian activation under hetero-species queens, suggesting that the queen pheromones more likely play a role of "honest signal" rather than a "repression" substance in the honeybee colonies. Thirdly, both species could mutually decode each other‘s waggle dances, with unexpectedly low misunderstanding; revealing that the dance language in a dark environment is quite adaptive for cavity-nesting honeybees. Fourthly, workers of both species could cooperate with each other in comb construction, although the combs they built contain many irregular cells. Interestingly, A. cerana workers could be stimulated by A. mellifera workers to perform this task, thus confirming self-organization theory in the colony. Fifthly, A. mellifera workers behaved more "defectively" in thermoregulation, but perhaps because A. cerana workers are more sensitive to changes in hive temperature. Given these differences in strategy, A. mellifera workers‘ performance might in fact reduce conflicts. Lastly, when faced with threats of predatory wasps, both species engaged in aggressive defence. Although they did not learn from each other‘s responses, species-specific strategies were adopted by each of them so that the defence of the mixed-colonies is very effective. I conclude that the two species can adapt to each other‘s efforts and task allocation is reasonably organized allowing mixed-species colonies to reach stability. These results suggest that all of the social behaviours discussed here were highly conserved following speciation. This thesis could provide some clues for the study of honeybee evolution from open-nesting to the transition of cavity-nesting.
- Full Text:
- Date Issued: 2010
Ecological infrastructure importance for drought mitigation in rural South African catchments: the Cacadu Catchment case example
- Authors: Xoxo, Beauten Sinetemba
- Date: 2021-10
- Subjects: Sustainable Development Goals , Water security South Africa , Remote sensing , Watershed restoration South Africa , Restoration ecology South Africa , Ecosystem services South Africa , SDG 15.3.1
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191203 , vital:45070
- Description: Water scarcity is recognised as one of the significant challenges facing many countries, including South Africa. The threat of water scarcity is exacerbated by the coupled impacts of climate and anthropogenic drivers. Ongoing droughts and continued land cover change and degradation influence the ability of catchments to partition rainwater runoff, thereby affecting streamflow returns. However, quantifying land degradation accurately remains a challenge. This thesis used the theoretical lens of investing in ecological infrastructure to improve the drought mitigation function in rural catchments. This theoretical framework allows for a social-ecological systems approach to understand and facilitate science-based strategies for promoting ecosystem recovery. Specifically, this study aimed to explore the role and benefit of ecological infrastructure for improving drought mitigation, and consequently, water security for rural communities. Thus, this study sought to assess the consequences of human actions to catchment health status using the 15th Sustainable Development Goal indicator for the proportion of degraded land over the total land area as a surrogate. Secondly, hydrological modelling was used to describe how different land covers influence catchment hydrology, which related to how ecological infrastructure enables drought risk-reduction for mitigation regulation. Finally, this study developed a spatial prioritisation plan for restoration to improve drought mitigation for four focal ecological infrastructure (EI) categories (i.e. wetlands, riparian margins, abandoned agricultural fields and grasslands). The focal EI categories were selected for their importance in delivering water-related ecosystem services when sustainably managed. Chapter 1 sets the scene (i.e. provides the study background) and Chapter 2 provides a review of the literature. In Chapter 3, the recently released global GIS toolbox (TRENDS.EARTH) was used for tracking land change and for assessing the SDG 15.3.1 degradation indicator of i.e. Cacadu catchment over 15 years at a 300 m resolution. The results showed a declining trend in biomass productivity within the Cacadu catchment led to moderate degradation, with 16.79% of the total landscape degraded, which was determined by the pugin using the one-out, all-out rule. The incidence of degradation was detected in middle reaches of the catchment (i.e. S10F-J), while some improvement was detected in upper reaches (S10A-C) and lower reaches (S10J). In Chapter 4, a GIS-based Analytic Hierarchical Process (AHP) based on community stakeholder priorities, open-access spatial datasets and expert opinions, was used to identify EI focal areas that are best suitable for restoration to increase the drought mitigation capacity of the Cacadu catchment. The collected datasets provided three broad criteria (ecosystem health, water provision and social benefit) for establishing the AHP model using 12 spatial attributes. Prioritisation results show that up to 89% of the Cacadu catchment is suitable for restoration to improve drought mitigation. Catchments S10B-D, and S10F, S10G and S10J were highly prioritised while S10A, S10E and S10H received low priority, due to improving environmental conditions and low hydrological potential. Areas that were prioritised with consideration for local livelihoods overlap the areas for drought mitigation and form a network of villages from the middle to lower catchment reaches. Prioritised restoration areas with a consideration of societal benefit made up 0.56% of wetlands, 4.27% of riparian margins, 92.06% of abandoned croplands, and 51.86% of grasslands. Chapter 5 reports on use of the Pitman groundwater model to help understand the influence of land modification on catchment hydrology, and highlight the role of restoration interventions. The Cacadu catchment is ungauged, therefore the neighbouring Indwe catchment was used for parameter transfer through a spatial regionalisation technique. Results suggest that degradation increases surface runoff and aggravates recharge reduction, thereby reducing streamflow during low flow periods. In areas where there is natural land cover recovery, the Pitman Model simulated similar dry season streamflow to the natural land cover. Combining the outcomes from the three assessments allowed the study to highlight the role and benefits of ecological infrastructure in terms of drought mitigation. Study findings were interpreted to make recommendations for the role and benefit of ecological infrastructure for drought mitigation at a landscape scale and tertiary catchment level, within the context of available management options. The results support the notion that multiple science data sources can promote investments in ecological infrastructure. However, better spatial and temporal resolution datasets at a national level are still needed to improve the accuracy of studies such as the one outlined in this thesis. The study recommends adopting better ecosystem protection approaches and collaborative governance at multiple levels to reduce the vulnerability of rural communities to drought impacts. , Thesis (MSc) -- Faculty of Science, Institute for Water Research, 2021
- Full Text:
- Date Issued: 2021-10
A study of the existence of equilibrium in mathematical economics
- Authors: Xotyeni, Zukisa Gqabi
- Date: 2008
- Subjects: Equilibrium (Economics) -- Mathematical models , Macroeconomics -- Mathematical models , Economics -- Mathematical models , Welfare economics -- Mathematical models , Lattice theory , Economics, Mathematical
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5418 , http://hdl.handle.net/10962/d1005232 , Equilibrium (Economics) -- Mathematical models , Macroeconomics -- Mathematical models , Economics -- Mathematical models , Welfare economics -- Mathematical models , Lattice theory , Economics, Mathematical
- Description: In this thesis we define and study the existence of an equilibrium situation in which producers maximize their profits relative to the production vectors in their production sets, consumers satisfy their preferences in their consumption sets under certain budget constraint, and for every commodity total demand equals total supply. This competitive equilibrium situation is referred to as the Walrasian equilibrium. The existence of this equilibrium is investigated from a various mathematical points of view. These include microeconomic theory, simplicial spaces, global analysis and lattice theory.
- Full Text:
- Date Issued: 2008
An investigation of how natural sciences teachers mediate learning of chemical reactions in Grade 9: a case study
- Authors: Xipu, Bukelwa
- Date: 2012
- Subjects: Science -- Study and teaching (Secondary) Science -- Study and teaching (Secondary) -- South Africa -- Eastern Cape Chemical reactions Science teachers -- South Africa -- Eastern Cape Science teachers -- Rating of -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1631 , http://hdl.handle.net/10962/d1003513
- Description: This research study involves two Grade 9 Natural Sciences teachers from two schools in the Lady Frere District of the Eastern Cape. The reason for selecting these two teachers is that in 2009 they, like me, obtained an Advanced Certificate in Education (Science and Maths) from Rhodes University. As a result, we have a good working relationship. Furthermore, both teachers are actively involved in the Natural Sciences curriculum in the District and their schools are not far from the District Office where I work. The principal objective of this study was to investigate how Natural Sciences teachers mediated learning in order to enhance conceptual development and understanding of chemical reactions in Grade 9. It was triggered by the transformation in curriculum in South Africa as well as by my experience of working with Natural Sciences teachers in our rural district. The study is informed by an interpretive paradigm using a qualitative case study approach. The data was gathered by administering analysis of documents, semi-structured interviews, observations, field notes and journals. During the data analysis process, patterns and themes were illuminated using the inductive analysis method. Rich data sets in relation to the main research question on how Natural Sciences teachers mediated learning in order to enhance conceptual development and understanding of chemical reactions in Grade 9 emerged from the analysed data. The conclusions that can be drawn from the study indicate that when teaching chemical reactions, teachers should have adequate content knowledge as well as pedagogical content knowledge. It is thus recommended that teachers consider the prior knowledge of learners, use a variety of teaching and learning approaches including practical activities, to make learning meaningful. The major limitation of this study is that the two selected teachers do not represent the whole population of Grade 9 teachers in the Lady Frere District. Therefore, the findings cannot be generalized to represent the larger population. It is recognised, however, that within the qualitative inquiry, reliability and generalizability play a minor role.
- Full Text:
- Date Issued: 2012