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Analysis of technical efficiency of small-scale maize producers: a case study in Tsolo magisterial district in O.R Tambo district in the Eastern Cape of South Africa

  • Authors: Avuletey, Richard
  • Date: 2014
  • Subjects: Corn -- Fertilizers -- South Africa -- Eastern Cape , Corn -- Economic aspects -- South Africa -- Eastern Cape , Entrepreneurship -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MSc Agric (Agricultural Economics)
  • Identifier: vital:11210 , http://hdl.handle.net/10353/d1016191 , Corn -- Fertilizers -- South Africa -- Eastern Cape , Corn -- Economic aspects -- South Africa -- Eastern Cape , Entrepreneurship -- South Africa -- Eastern Cape
  • Description: Maize is the most important cereal crop grown in South Africa. This crop is produced throughout the country under diverse conditions and in diverse environments. The study only focuses on technical efficiency because it is an important subject in developing agriculture where resources are limited, but high population growth is very common. In such a setting, increased output will depend more on efficiency improvements and assessing the scope for such efficiency improvements within the system is a crucial need. The objective of the study was to determine the level of technical efficiency and to identify the socio-economic and institutional characteristics as well as the entrepreneurial spirit that influence the technical efficiency of small-scale maize producers in the Tsolo magisterial district. Purposive and Snowball sampling techniques were used to collect primary data from 120 small-scale farmers. The stochastic frontier model was used to determine the level of technical efficiency. The Multivariate OLS was used to analyze the socio-economic factors and institutional characteristics that have influenced the technical efficiency of maize production. A similar linear regression model was used to estimate the influence of positive psychological capital and entrepreneurial spirit on the technical efficiency of maize production. The stochastic results revealed that small-scale farmers in Tsolo are technically efficient at 98 percent in maize production and experience increasing return to scale (1.37), which means that increase in the use of inputs, will as well increase their productivity and efficiency. The inefficiency model results indicated that age, years in farming, household size and extension contact significant and 3 variables, namely, as years in farming, extension contact and farm size are significant in the OLS model. Lastly the results of the linear regression indicated that, out of the 4 variables estimated in the entrepreneurial spirit, self-efficacy and resilience were significant with respect to its responsiveness to total maize output.
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  • Date Issued: 2014

Development of styrene based imprinted sorbents for selective clean-up of metalloporphyrins in organic media

  • Authors: Awokoya, Kehinde Nurudeen
  • Date: 2014
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/54521 , vital:26580
  • Description: Most crude oils contain traces of vanadium and nickel complex with porphyrins (VTPP and NTPP) within their asphaltene fraction. Although these metals are only present in trace quantities, they have a significant and detrimental impact on the refining process by degrading the quality of intermediate and end products. Therefore, their selective removal is highly desirable. This thesis presents the development of nickel porphyrin, nickel vanadyl porphyrin imprinted nanofibers and vanadyl porphyrin imprinted polymer (MIP) particles for application as selective sorbents. Computational model based on the combination of molecular dynamics simulations and quantum mechanics was successfully applied to the styrene functional monomer selection. The particle was prepared by bulk polymerization and the nanofibers by a novel approach combining molecular imprinting and electrospinning technology. The morphologies, thermal stabilities and porosities of the imprinted sorbents were studied using SEM, TGA, and BET nitrogen gas adsorption. Chloroform was found to swell the polymer particles to a higher degree than methanol and acetonitrile. The adsorption characteristics of the imprinted sorbents best fitted with Freundlich isotherm model. The imprinted sorbents recorded high extraction efficiencies (EEs) of > 99 % in selectively extracting the metalloporphyrins. The impact of the template on the affinity of recognition for NTPP was evaluated. The results showed that the NTPP adsorption capacity increased as the molar ratio of NTPP to styrene was increased from 1:1 to 3:1. The optimal ratio of template to functional monomer which yielded the best specific affinity and highest recovery (99.9 %) was 3:1. The effects of trifluoroacetic acid (TFA), dichloromethane (DCM), dimethyl sulphoxide (DMSO), pentane (PEN) on electro-spinnability of the polymer solutions and the morphological appearance of the nanofibers were investigated. The imprinted nanofibers exhibited the same selectivity specialism for both NTPP and VTPP. A remarkable stability in relation to reusability was observed when imprinted nanofibers were used, as they could be reused nine times without incurring any significant loss in removal efficiency. The results were validated by analysing a certified reference material. The imprinted sorbents were therefore found to be selective sorbents that are well suited for handling trace metals in organic media.
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  • Date Issued: 2014

Effect of diet and sex-sorting on growth and gonad development in farmed South African abalone, Haliotis midae

  • Authors: Ayres, Devin William Philip
  • Date: 2014
  • Subjects: Haliotis midae -- South Africa , Haliotis midae fisheries -- South Africa , Abalone culture -- South Africa , Abalones -- Physiology -- South Africa , Abalones -- South Africa -- Growth , Abalones -- Feeding and feeds -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5357 , http://hdl.handle.net/10962/d1010856 , Haliotis midae -- South Africa , Haliotis midae fisheries -- South Africa , Abalone culture -- South Africa , Abalones -- Physiology -- South Africa , Abalones -- South Africa -- Growth , Abalones -- Feeding and feeds -- South Africa
  • Description: Abalone, Haliotis midae, farmers in South Africa that feed formulated diets reported a periodic drop in abalone growth during periods of increased gonad development. A large drop in abalone biomass was noticed after presumed spawning events. This study was aimed to determine the effect of diet and sex-sorting on gonad development in abalone. Experiments were conducted on a commercial abalone farm from July 2012 to the end of June 2013. Isonitrogenous and isoenergetic diets were formulated with two protein sources. A fishmeal and soybean meal (S-diet) diet and a fishmeal only (F-diet) diet were fed to abalone (50 - 70 g abalone⁻¹) over 12 months. Weight and length gain, gonad bulk index (GBI), visceral index (%) and meat mass index (%) were determined monthly and seasonally. A histological study on the female gonads was conducted. This study also included an experiment to test the effect of sex-sorting (70 - 80 g abalone⁻¹) on growth and body composition with treatments including males (M), females (F) and equal numbers of males and females (MF). Weight gain and length gain were faster in S-diet-fed abalone (RM-ANOVA, F ₍₁, ₁₆₎ = 7.77, p = 0.01; F ₍₁, ₆₉₎ = 49.9, p < 0.001, respectively). Gonad development was significantly affected by the inclusion of soybean meal with S-diet-fed abalone showing higher GBI-values than F-diet-fed abalone (RM-ANOVA, F ₍₁, ₃₃)= 16.22, p = 0.0003). Male abalone had higher GBI-values than females (RM-ANOVA, F ₍₁, ₃₃₎ = 39.87, p < 0.0001). There was no significant difference in average feed conversion ratio (FCR) between diets over time (RM-ANOVA, F ₍₁, ₂₁₎ = 0.008, p = 0.97). However, average FCR-values were significantly highest between November 2012 and March 2013, the presumed spawning season. The visceral mass (gut and gonad) as a proportion of whole mass (visceral index, %) was significantly higher in abalone fed the S-diet (RM-ANOVA; F ₍₁, ₆₉₎ = 68.06, p < 0.0001). There was no difference in meat mass index (%) between diets for both male and female abalone (RM-ANOVA; F ₍₇, ₂₄₈₎ = 0.80, p = 0.60; F ₍₇, ₂₄₁₎ = 1.7, p = 0.11,respectively). Meat mass index significantly decreased from September 2012 to February 2013 coinciding with the period of high GBI-values. The distribution of oocyte maturity stages differed between diets. The majority of oocytes within S-diet-fed abalone were fully mature stage 8 oocytes compared to a majority of stage 7 oocytes in F-diet-fed abalone. Histology corroborated peaks in GBI-values for abalone fed both diets. There was no significant difference in growth, GBI, visceral index (%) and meat mass index (%) between abalone sorted into monosex and mixed-sex populations. Thus, the presence of the opposite sex did not have an effect on growth and gonad mass in H. midae. The phytoestrogens daidzin, glycitin, genistin, daidzein, glycitein and genistein were present in soybean meal and only traceable amounts were found in the F-diet. This study provided evidence that soybean meal present in formulated feed affected growth and gonad development in H.midae. The difference in the distribution of the maturity stages of oocytes was affected by diet. Sex-sorting abalone into monosex and mixed-sex populations had no influence on weight and length gain and gonad development.
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  • Date Issued: 2014

Development finance in small and medium enterprises in Matjhabeng Municipality

  • Authors: Babalola, Oluwanifesimi Omolade
  • Date: 2014
  • Subjects: Business enterprises -- South Africa -- Finance , Economic development -- South Africa
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: vital:9187 , http://hdl.handle.net/10948/d1020215
  • Description: It has been generally accepted within the developed and developing countries of the world that SMES contributes significantly to employment creation as the world population increases and that it also contributes to the economic growth of the areas they are situated in. Finance is the blood (life) of any business, for a business to be successful it needs steady successful access to funds and post financial support which leads to actualization of ideas, leads to investment and expansion, improves access to market amongst others. This is why the impact of development finance can never be over emphasized. The aims of the study are: To understand the extent to which small and medium businesses are supported through the availability of financial assistance in Matjabeng Municipality. To establish the survival rates of businesses that has been funded and or supported and whether they are or not sustainable. In achieving the aims and objectives of the research, the researcher looked at development funds both from the supply side and the demand side. The supply side which involved semi structured interviews with consultants of government parastatals (the FDC and DETEA) who are involved in financing Small Medium Enterprises in Matjhabeng municipality. The demand side involved administering of questionnaires to Entrepreneurs in the municipality who are registered with the Local Economic Department (LED), which led to the acceptance of the hypothesis of the research that development finance actually helps in the growth of small medium enterprises but in conjunction with post financial support such as bookkeeping, accounting, monitoring and evaluation. The researcher also discovered some findings amongst others which includes: The most effective ways entrepreneurs heard about funding in the municipality are through the media and word of mouth. Most of the entrepreneurs that received some type of funding are startups. More entrepreneurs that had access to funds also got some post financial business support. Financial assistance to entrepreneurs yielded improvements after respondents received financial assistance, the range of goods offered was improved and more jobs were created, entrepreneurs were able to obtain better business premises either by renting or buying and entrepreneurs had access to better equipment. Some of the recommendations of this study includes; The municipal government should help small and medium enterprises in the municipality by linking them to new markets. Effective monitoring and evaluation systems should be put in place by development funders and non-financial support services. Entrepreneurial skills development should be provided by the public and private agencies by organizing workshops for aspiring entrepreneurs in order to expose them to business opportunities that are sustainable and viable.
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  • Date Issued: 2014

Klazinga - response to allegations

  • Authors: Badat, Saleem
  • Date: 2014
  • Language: English
  • Type: Text
  • Identifier: vital:7875 , http://hdl.handle.net/10962/d1016424
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  • Date Issued: 2014

A response to the South African Jewish report and Ms Klazinga on "Jews unwelcome at Rhodes"

  • Authors: Badat, Saleem
  • Date: 2014
  • Language: English
  • Type: text
  • Identifier: vital:7883 , http://hdl.handle.net/10962/d1016432
  • Description: On 1 January 2014, the South African Jewish Report and Ms Larissa Klazinga made a number of unfounded claims and unsubstantiated allegations against Rhodes University. Stripped of the hysteria, lies and inaccuracies, the central claim made is that Rhodes University is hostile to Jews and seeks to be rid of Jews. We reject with contempt these baseless and self-serving claims and allegations of the South African Jewish Report and Klazinga. Rhodes is committed to an institutional culture that respects and promotes equity, human dignity and human rights, embraces difference and diversity and is comfortable for all people irrespective of ‘race’, gender, language, culture, nationality, sexual orientation and religion. Rhodes welcomes all and will continue to strive to be a Home for All.
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  • Date Issued: 2014

The post-secondary education system: Towards policy formulation for equality and development

  • Authors: Badat, Saleem
  • Date: 2014
  • Language: English
  • Type: Text
  • Identifier: vital:7861 , http://hdl.handle.net/10962/d1016410
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  • Date Issued: 2014

Citizenship rights : still a long road to travel - Graduation Ceremonies address 2014

  • Authors: Badat, Saleem
  • Date: 2014
  • Language: English
  • Type: Text
  • Identifier: vital:7872 , http://hdl.handle.net/10962/d1016421
  • Description: The 20th anniversary of our democracy is a good time to reflect on the progress that we have made with respect to citizenship in post-1994 South Africa. 1994 was a revolutionary breakthrough. From being a racially exclusive authoritarian society in which millions were downtrodden subjects, we became a democracy in which for the first time almost all inhabitants became citizens. Critical here was a commendable Constitution, including a Bill of Rights, which held out the promise of an extensive range of human, social and economic rights that did not exist for all or at all prior to 1994. During the past 20 years there have been significant economic and social gains and achievements. At the same time, there continue to be many challenges, and key institutions of our democracy have come under strain as a result of too many in power seeking to use the state as their private piggy bank. Still, a relatively independent judiciary, free media, autonomous universities and the like remain intact. Witness in this regard the magnificent performance of the Public Protector’s office under Thuli Madonsela. However, a number of contemporary realities, compromise the ideal of full and substantive citizenship rights for all that the Constitution promises. Indeed, they condemn large numbers of people to conditions that are associated with subjecthood and being subjects.
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  • Date Issued: 2014

Vice-Chancellor's 2014 Address to Graduation Ceremonies

  • Authors: Badat, Saleem
  • Date: 2014
  • Language: English
  • Type: text
  • Identifier: vital:7868 , http://hdl.handle.net/10962/d1016417
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  • Date Issued: 2014

Vice-Chancellor's 2014 Address to Graduation Ceremonies

  • Authors: Badat, Saleem
  • Date: 2014
  • Language: English
  • Type: text
  • Identifier: vital:7869 , http://hdl.handle.net/10962/d1016418
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  • Date Issued: 2014

Prevalence and pathogenicity of vibrios in treated final effluents of selected wastewater treatment plants in the Amathole District Municipality of Eastern Cape Province of South Africa

  • Authors: Badela, Andiswa Unathi
  • Date: 2014
  • Subjects: Sewage disposal plants -- South Africa -- Eastern Cape , Whole effluent toxicity testing -- South Africa -- Eastern Cape , Escherichia coli -- South Africa -- Eastern Cape , Bacterial diseases -- Pathogenesis
  • Language: English
  • Type: Thesis , Masters , MSc (Microbiology)
  • Identifier: vital:11284 , http://hdl.handle.net/10353/d1019774 , Sewage disposal plants -- South Africa -- Eastern Cape , Whole effluent toxicity testing -- South Africa -- Eastern Cape , Escherichia coli -- South Africa -- Eastern Cape , Bacterial diseases -- Pathogenesis
  • Description: Waterborne diarrhoeal infections continue to be a major health setback in developing countries, especially in rural areas which lack adequate supply of portable water and sanitation facilities. Globally, waterborne diarrhoeal infections occur with an estimated mortality rate of 10–25 million deaths per year, 95% of which are children under the age of 5 years. The Vibrio species is one of the major groups of enteric pathogens that are responsible for diarrhoeal infections. Many strains of these bacterial species continue to cause epidemics of diarrhoea throughout the world. In this study, the prevalence of Vibrio pathogens in wastewater final effluents was assessed. Wastewater final effluent and discharge point samples were collected monthly between September 2012 and August 2013. All samples were collected aseptically using sterile 1 L Nalgene bottles containing 0.5 ml of sterile sodium thiosulphate solution and transported on ice to the laboratory for analyses within 6 h of collection. The membrane filtration method was used for enumeration of presumptive Vibrio densities on thiosulfate citrate bile salt (TCBS) agar plates. Polymerase chain reaction (PCR) was then used to confirm the identities of the presumptive Vibrio species using the species-specific primers. The confirmed isolates were further subjected to molecular characterization to confirm their respective pathotypes. Presumptive Vibrio densities varied from 0 to 2.11 × 102 cfu/100 ml. Out of 300 confirmed Vibrio isolates; 13.3% (40/300) were Vibrio fluvialis, 22% (66/300) were confirmed to be Vibrio parahaemolyticus, and 24.7% (74/300) proved to be Vibrio vulnificus, and 40% (120/300) were other Vibrio species which were not assessed for in this study. The strains of Vibrio fluvialis were found to exhibit 100% resistance to Polymixin and Tetracycline. However, Gentamicin was active against all the three Vibrio species selected for the purpose of this research. The recovery of Vibrio species in the discharged effluents throughout the sampling period even in adequately disinfected effluents is not acceptable considering the fact that Vibrio is a pathogenic bacterium. The findings of this study underline the need for constant monitoring of the microbiological qualities of discharged effluents and might also be suggestive for a review of the disinfection methods used at the treatment works.
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  • Date Issued: 2014

A systematic review of the effectiveness of animal-assisted interventions

  • Authors: Badenhorst, Estelle
  • Date: 2014
  • Subjects: Animals -- Therapeutic use , Human-animal relationships
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:9980 , http://hdl.handle.net/10948/d1021139
  • Description: There is a global increase in research on the benefits of animals and the value of incorporating them into interventional practices. This is referred to as animal-assisted interventions. Due to the novelty of this type of intervention and the accompanying complexity of variables, a need exists to explore the various aspects within these interventions. Looking specifically at animal-assisted interventions within the mental health field, this study focuses on the psycho-therapeutic value of companion animals, such as dogs and cats. The primary aim of this study was to identify the mechanisms through which an animal-assisted intervention exerts its influence. A secondary aim was to indentify salient methodological aspects within the included studies. A systematic review of existing literature was undertaken to explore these factors. Each study was appraised against specific inclusion and exclusion criteria and themes were extracted. The data was synthesised, integrated and discussed in relation to previously conducted studies in relevant fields. Six themes emerged from the systematic review. These included enhanced comfort, the living nature of animals, physical contact, adjunctive nature, an affinity for animals, as well as methodological considerations. Based on these emergent themes conclusions were drawn as to the psycho-therapeutic influences of companion animals. This may serve as informative knowledge regarding animal-assisted interventions for practitioners seeking additional methods to reach treatment goals. Information is also provided for researchers interested in the field, particularly methodological considerations, before embarking on a study of animal-assisted intervention efficacy.
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  • Date Issued: 2014

A needs-ICTD strategy alignment framework foundation for the measurement of ICTD impact

  • Authors: Baduza, Gugulethu Qhawekazi
  • Date: 2014
  • Subjects: Siyakhula Living Lab SAP Research Needs assessment -- Information technology -- Social aspects -- South Africa -- Case studies Information technology -- South Africa -- Management -- Case studies Information technology -- Social aspects -- South Africa Rural development -- Economic aspects -- South Africa Rural development -- South Africa -- Sociological aspects Rural development projects -- South Africa
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: vital:1155 , http://hdl.handle.net/10962/d1011116
  • Description: Many Information and Communication Technologies for Development (ICTD) projects are established with the overall aim of positively developing the communities they are implemented in. However, the solutions that are provided are often commonly developed without the needs of these communities being sufficiently investigated beforehand. As a result the ICTD strategy of the project ends up not well aligned with the aims and targets of the needs of the community. As a result of this, an appropriate programme theory for the project and relevant impact indicators fail to be adequately developed. Consequently, when an impact assessment is conducted it is often found that the intended effects are not directly linked to the needs of the community or what the community had hoped to gain from the ICTD initiative. The purpose of this research serves to develop a needs-ICTD strategy alignment foundation that supports the identification and formulation of impact assessment indicators. Through this research, a framework is developed to support the alignment of ICTD strategy, the development and the promotion of contextual needs of rural communities and other frequently marginalized areas. The Needs-ICTD strategy alignment framework is composed of eight main components that describe the process that can be used to align ICTD strategy with community needs. These components include: collaboration between the internal and external stakeholders, the development of the community, conducting baseline studies, the needs assessment, the ICTD strategy, linking of the needs-ICTD strategy, and lastly the identification of impact indicators. An interpretive research approach is used to explore and inform the framework through a multi-case study investigation of the Siyakhula Living Lab and two projects in the Systems Application Products (SAP) Living Lab. Two main case study questions drive the exploration of the framework, that being: 1) How are the needs of the community elicited and how is the ICTD strategy aligned to the needs of the community? 2) And, why were the selected approaches chosen for aligning the needs of the community and ICTD strategy? Data for this research was collected qualitatively through interviews, document analysis and participant observation. Key findings indicate that the involvement of internal (local) stakeholders in the development and alignment of ICTD strategy to the needs of the community is still lacking. As a consequence, many community members end up not fully understanding the project objectives and how these objectives aims are to be achieved. The research also finds that ‘solution specific’ projects also fail communities as they focus specifically on one target group and repeatedly fail to assist the community holistically in supporting their information and their community development needs.
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  • Date Issued: 2014

South Africa's 'Border War': contested narratives and conflicting memories

  • Authors: Baines, Gary F
  • Date: 2014
  • Language: English
  • Type: text , book
  • Identifier: http://hdl.handle.net/10962/67115 , vital:29033 , https://www.bloomsbury.com/uk/south-africas-border-war-9781472508249/
  • Description: publisher version , South Africa's 'Border War' provides a timely study of the 'war of words' waged by retired South African Defence Force (SADF) generals and other veterans against critics and detractors. The book explores the impact of the 'Border War' on South African culture and society during apartheid and in the new dispensation and discusses the lasting legacy or 'afterlife' of the war in great detail. It also offers an appraisal of the secondary literature of the 'Border War', supplemented by archival research, interviews and an analysis of articles, newspaper reports, reviews and blogs. Adopting a genuinely multidisciplinary approach that borrows from the study of history, literature, visual culture, memory, politics and international relations, South Africa's 'Border War' is an important volume for anyone interested in the study of war and memory or the modern history of South Africa.
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  • Date Issued: 2014

Smallholder farmers’ access to credit in the Amathole District Municipality, Eastern Cape Province, South Africa

  • Authors: Baiyegunhi, Lloyd J S , Fraser, Gavin C G
  • Date: 2014
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/69351 , vital:29503 , https://jarts.info/index.php/jarts/article/view/2014121946870/814
  • Description: Provision of credit has being identified as an important instrument for improving the welfare of smallholder farmers directly and for enhancing productive capacity through financing investment by the farmers in their human and physical capital. This study investigated the individual and household characteristics that influence credit market access in Amathole District Municipality, Eastern Cape Province, South Africa, using a cross sectional data from smallholder farmers’ household survey. The aim is to provide a better understanding of the households’ level socio-economic characteristics, not only because they influence household’s demand for credit but also due to the fact that potential lenders are most likely to base their assessment of borrowers’ creditworthiness on such characteristics. The results of the logistic regression suggest that credit market access was significantly influenced by variables such as gender, education, households’ income, value of assets, savings, dependency ratio, repayment capacity and social capital. Implications for rural credit delivery are discussed.
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  • Date Issued: 2014

Inter-individual variability and phenotypic plasticity : the effect of the environment on the biogeography, population structure, ecophysiology and reproduction of the sandhoppers Talorchestia capensis and Africorchestia quadrispinosa

  • Authors: Baldanzi, Simone
  • Date: 2014
  • Subjects: Phenotypic plasticity -- Research -- Africa, Southern Talitridae -- Research -- Africa, Southern Amphipoda -- Research -- Africa, Southern Climatic changes -- Environmental aspects -- Africa, Southern Marine biology -- Africa, Southern Adaptation (Biology) -- Africa, Southern
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5846 , http://hdl.handle.net/10962/d1011447
  • Description: Climatic envelope models focus on the climatic variables affecting species or species assemblages, and are important tools to investigate the effect of climate change on their geographical ranges. These models have largely been proposed in order to make successful predictions on species‘ persistence, determining which variables are likely to induce range expansion, contraction, or shifting. More recent models, including the ability and the cost for individuals to respond promptly to an environmental stimulus, have revealed that species may express phenotypic plasticity able to induce adaptation to the new environment. Consequently, understanding how species evolve to a changing climate is fundamental. From this perspective, investigating intraspecific responses to an environmental variable may contribute to better understanding and prediction of the effect of climate change on the geographical range and evolution of species, particularly in the case of widespread species. In this context, the present study aimed at establishing how environmental variables (focussing mainly on temperature) may have contributed to shape the spatial distribution, physiology, reproductive biology and connectivity of two species of Southern African sandhoppers (Talorchestia capensis and Africorchestia quadrispinosa, Amphipoda, Talitridae). Most of the work was carried out on T. capensis, due to its widespread spatial distribution. A first investigation of the biogeography of T. capensis and A. quadrispinosa, revealed that, for both species, spatial patterns of abundance, size and sex ratio were not explained by the Abundant Centre Hypothesis (greater abundance at the core of a spatial range), but rather guided by bio-physical forces. Precisely, the abundance of sandhoppers was driven by the morphodynamic state of the beach, salinity and temperatures, with strong differentiation among sites that reflected local environmental conditions. In support of these findings, strong population structure in the genetics of T. capensis was found (three main groups) when investigating its phylogeography and genetic connectivity. Although such defined structure may suggests cryptic speciation, the concomitant within-population variation in the COX1 region of mtDNA, also highlighted the importance of individual genetic variability. High individual variability was also found in the response of T. capensis to temperature, both in its physiology (thermal plasticity) and its reproductive biology (maternal effects). Since temperature is one of the main variables affecting the coastal marine systems of southern Africa and the metabolism of animals in general, its effect on the physiology and reproduction of T. capensis was therefore investigated. Thermal responses to increasing/decreasing temperatures were assessed for separated populations of T. capensis. Individual variability was reported in the oxygen consumption of T. capensis in response to temperature (high variation around the means, especially for increasing temperatures). Among population differences in thermal sensitivity were significantly correlated with air temperature variability experienced over the past 23 years, highlighting the importance of historical temperature fluctuations to the current thermal physiology of these sandhoppers. Temperature also had an important effect on the reproductive plasticity of T. capensis. Different temperatures induced mothers to adjust the size of their offspring (i.e. egg size), with larger eggs produced at lower temperatures. Interestingly, females showed strongly significant among individual variation in the size of the eggs. Given the importance of understanding rapid responses of organisms to climate change and considering the fundamental role played by phenotypic plasticity in evolution, the overall study revealed the significance of individual plasticity and variability in response to the environment and highlighted its importance. Particularly, studying the thermal physiology of separated populations and understanding within population reproductive plasticity in response to temperature, helped to clarify how differences among individual responses have important consequences at the population level, possibly explaining the widespread distribution of T. capensis.
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  • Date Issued: 2014

An investigation into the use of a ceramifiable Ethylene Vinyl Acetate (EVA) co-polymer formulation to aid flame retardency in electrical cables

  • Authors: Bambalaza, Sonwabo Elvis
  • Date: 2014
  • Subjects: Vinyl acetate , Polymeric composites , Inorganic compounds
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10433 , http://hdl.handle.net/10948/d1020159
  • Description: The concept of a unique ceramifiable Ethylene vinyl acetate (EVA) based polymer composite was based on the incorporation of inorganic compounds such as aluminium hydroxide, calcium carbonate, muscovite mica, and calcined kaolinite within a 95 percent EVA/ 5 percent Polydimethylsiloxane (PDMS) polymer matrix such tha t upon heating to elevated temperatures of about 1000 oC, a solid end-product with ceramic-like properties would be formed. The ceramifiable EVA based polymer composite was developed to be used as electric cable insulation or sheath as the formation of a ceramic based material at elevated temperatures would provide flame retardant properties during fire situations. The flame retardant properties at elevated temperatures would ensure that the insulation remains at such temperatures due to some of the properties of the resultant ceramic such as reasonably high flexural strength, high thermal stability, non-reactivity and high melting point. During a fire this would ensure that flames would not be propagated along the length of the cable and also protect the underlying conducting wires from being exposed to the high temperatures of the fire. Its application as a cable insulation also required that the material functions as a cable insulator under ambient temperature conditions where the ceramifiable polymer composite should retain certain polymer properties such as the post-cure tensile strength (MPa), degree of polymer elongation (percent), thermal expansion, thermal slacking, limited oxygen index and electrical insulation. This study made use of a composite experimental design approach that would allow for the optimization of the amounts of the additives in the ceramifiable polymer composite giving both the desired mechanical properties of the material under normal operating temperatures as a polymer and also as a ceramic once exposed to elevated temperatures. The optimization of additives used in the ceramifiable polymer composite was done by using a D-optimal mixture design of experiments (DoE) which was analyzed by multiple linear regression.
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  • Date Issued: 2014

My grandmother breaks her hip

Modelling the hydrological responses to changes in land use and cover in the Malaba River Catchment, Eastern Uganda

  • Authors: Barasa, Bernard
  • Date: 2014
  • Subjects: Hydrologic models -- Uganda , Runoff -- Uganda
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:10670 , http://hdl.handle.net/10948/d1020153
  • Description: Hydrological responses vary from one catchment to another, depending on the nature of land use and cover changes. Modelling the hydrological responses to changes in land use and cover at different catchment spatial scales was the major focus of this study. This study assessed the hydrological responses attributed to changes in land use and extreme weather events resulting into increased sediment loading/concentration, rainfall-runoff generation/volume, streamflow fluctuation and modification of the river channel in the Malaba River Catchment, Eastern Uganda. The hydrological responses were assessed using hydrological models (IHACRES, SCS CN, and SHETRAN) to examine the effect of land use on soil physio-chemical properties susceptibility to rainfall-runoff generation and volume, frequency and severity of extreme weather events, changes in streamflow variations, sediment loading/concentration and river channel morphology. The preliminary study results showed that the frequency of extreme weather events reduced from 4-10 to 1-3 years over the catchment. The performance of the IHACRES model with a Nash-Sutcliffe Efficiency (NSE) of 0.89 showed that streamflow comparatively corresponded with the results obtained the drought indices in predicting the recorded events of severe drought (2005) and flood (1997). Changes in land use and cover types showed that the highest change in the gain of land was experienced from the agricultural land use (36.7 percent), and tropical forest (regeneration) (2.2 percent). The biggest losses in land were experienced in the wetlands (24.6 percent) and bushland and thickets (15.3 percent) land cover types. The SHETRAN model calibrated period had a NSE of 0.78 and 0.81 in the validation period showed satisfactory fits between the measured and simulated streamflow. The agricultural land use (crop growing) had a higher influence on the rainfall-runoff generation and increase in the streamflow than the tropical forest, and bushland cover types in the simulated period. Similarly, the curve number model estimated a comparatively higher surface rainfall-runoff volume generated from the agricultural land use (crop growing) (71,740 m3) than in the bushlands and thickets (42,872 m3) from a rainstorm followed by the tropical forest cover type. This was also reflected in the lower rates of saturated hydraulic conductivity from the agricultural land use (crop growing). The study also showed that human-induced sediment loading due to gold mining activities contributed a much higher impact on the concentration of suspended sediments and streamflow than sediments from rainfall-runoff from the sampled streams. The main contributor of human-induced sediments to the Malaba River were Nankuke River (130.6kg/annum), followed by Omanyi River (70.6kg/annum), and Nabewo River (66.8kg/annum). Human-induced sediment loading had a profound impact on the streamflow variations both in the dry and wet seasons from the sampled tributaries. Lastly, in regard to the effect of land use and cover types on the river channel morphology, tree plantation (cohesion=12, angle of internal friction=27) and bushland and thickets (cohesion=14, angle of internal friction=22) cover types had the most stable river banks compared to the wetland and agricultural land use and cover types that exhibited higher levels of sediment concentration.
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  • Date Issued: 2014

An exploration of the way in which values and valuing processes might strengthen social learning in water stewardship practices in South Africa

  • Authors: Barnes, Garth
  • Date: 2014
  • Subjects: Integrated water development -- South Africa -- Case studies , Water conservation -- South Africa -- Case studies , Water-supply -- Moral and ethical aspects -- South Africa , Environmental education -- South Africa , Social learning -- South Africa
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1975 , http://hdl.handle.net/10962/d1012940
  • Description: This qualitative study, focussing on the way in which values and valuing processes might strengthen social learning in water stewardship practices in South Africa, is located within the broader global narrative that describes the scale of human impact on our Earth systems and that is setting humanity on a trajectory that threatens to place us beyond the safe operating spaces called planetary boundaries. For humanity to live within planetary boundaries – one of which is global freshwater use –will take a new way of relating to the environment called Earth stewardship, which calls for a new ethic of responsibility towards Earth systems. It is at the local level of stewardship within a global approach to water resources management called integrated water resources management that this qualitative study is contextually bound. Two case studies, located in the catchment management forums (CMFs) of the Upper Vaal catchment of Gauteng, South Africa, are used in an exploration of the way in which values and valuing processes might strengthen social learning in water stewardship practices in South Africa. The meta-theory of critical realism is used to help explore this relationship between values, practice and social learning. The study uses document analysis, interviews and observation of selected water stewardship practices to identify held and assigned values, and valuing processes and their influence on social learning, and the framing and de-framing processes that occur in social learning oriented towards water stewardship practices. The study differentiates between held and assigned values and identifies a strong altruistic-held values tendency that characterises forum participants who practice water stewardship in the two case study sites. Most water stewardship practice, identified in the case study sites, manifests as compliance activities in the public – or forum – space, while private-sphere environmentalism is mostly left to the confines of the individual’s private household. Lastly, the CMFs seem to have the potential to provide a space for social learning that is not yet maximised. Drawing from these key findings, the study’s major recommendation is that forums that facilitate learning, either using the current CMF structure or creating new opportunities, need to be provided as a conduit for social learning and reflexivity to make the existing boundaries between private and public forms of water stewardship more porous. This social learning may expand social practice and thus strengthen social change processes that expand water stewardship practices.
  • Full Text:
  • Date Issued: 2014
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