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Mechanism and synchronicity of wheat (Triticum aestivum) resistance to leaf rust (Puccinia triticina) and Russian wheat aphid (Duiraphis noxia) SA1

  • Authors: Njom, Henry Akum
  • Date: 2016
  • Subjects: Wheat -- Disease and pest resistance Bacterial diseases of plants Russian wheat aphid
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10353/2700 , vital:28056
  • Description: Wheat (Triticum aestivum and T. Durum) is an extremely important agronomic crop produced worldwide. Wheat consumption has doubled in the last 30 years with approximately 600 million tons consumed per annum. According to the International Maize and Wheat Improvement Center, worldwide wheat demand will increase over 40 percent by 2020, while land as well as resources available for the production will decrease significantly if the current trend prevails. The wheat industry is challenged with abiotic and biotic stressors that lead to reduction in crop yields. Increase knowledge of wheat’s biochemical constitution and functional biology is of paramount importance to improve wheat so as to meet with this demand. Pesticides and fungicides are being used to control biotic stress imposed by insect pest and fungi pathogens but these chemicals pose a risk to the environment and human health. To this effect, there is re-evaluation of pesticides currently in use by the Environmental Protection Agency, via mandates of the 1996 Food Quality Protection Act and those with higher perceived risks are banned. Genetic resistance is now a more environmental friendly and effective method of controlling insect pest and rust diseases of wheat than the costly spraying with pesticides and fungicides. Although, resistant cultivars effectively prevent current prevailing pathotypes of leaf rust and biotypes of Russian wheat aphid from attacking wheat, new pathotypes and biotypes of the pathogen/pest may develop and infect resistant cultivars. Therefore, breeders are continually searching for new sources of resistance. Proteomic approaches can be utilised to ascertain target enzymes and proteins from resistant lines that could be utilised to augment the natural tolerance of agronomically favourable varieties of wheat. With this ultimate goal in mind, the aim of this study was to elucidate the mechanism and synchronicity of wheat resistance to leaf rust (Puccinia triticina) and Russian wheat aphid (Duiraphis noxia) SA1. To determine the resistance mechanism of the wheat cultivars to leaf rust infection and Russian wheat aphid infestation, a proteomics approach using two-dimensional gel electrophoresis was used in order to determine the effect of RWA SA1 on the wheat cultivars proteome. Differentially expressed proteins that were up or down regulated (appearing or disappearing) were identified using PDQuestTM Basic 2-DE Gel analysis software. Proteins bands of interest were in-gel trypsin digested as per the protocol described in Schevchenko et al. (2007) and analysed using a Dionex Ultimate 3000 RSLC system coupled to an AB Sciex 6600 TripleTOF mass spectrometer. Protein pilot v5 using Paragon search engine (AB Sciex) was used for comparison of the obtained MS/MS spectra with a custom database containing sequences of Puccinia triticina (Uniprot Swissprot), Triticum aestivum (Uniprot TrEMBL) and Russian wheat aphid (Uniprot TrEMBL) as well as a list of sequences from common contaminating proteins. Proteins with a threshold of ≥99.9 percent confidence were reported. A total of 72 proteins were putatively identified from the 37 protein spots excised originating from either leaf rust or Russian wheat aphid experiments. Sixty-three of these proteins were associated with wheat response to stress imposed by RWA SA1 feeding while 39 were associated with infection by Puccinia triticina. Several enzymes involved in the Calvin cycle, electron transport and ATP synthesis were observed to be differentially regulated suggesting greater metabolic requirements in the wheat plants following aphid infestation and leaf rust infection. Proteins directly associated with photosynthesis were also differentially regulated following RWA SA1 infestation and P.
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  • Date Issued: 2016

Media and communication influences on farmers' views of water conservation in the Garden Route, South Africa

  • Authors: Buckle, Dorothea Maria
  • Date: 2016
  • Subjects: Water-supply, Agricultural -- South Africa , Sustainable agriculture , Mass media in agricultural extension work
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10948/9109 , vital:26465
  • Description: The Garden Route is situated between a mountain range and the ocean, both within close proximity. These geographic considerations make the farmers in the area vulnerable to extreme weather events, especially droughts and floods, which have been experienced in recent years. Agriculture in the area is predominantly focused on dairy and vegetables, which require intensive irrigation practices. It is this water demand that inspired adaptations to counteract the risks of extreme weather and dwindling water sources. These adaptations and behaviours were investigated to determine the underlying perceptions and influences. The research aimed to understand the way environmental knowledge would disseminate through the use of the Diffusion of Innovation theory, whilst determining the ecological worldviews of the participants through the use of the New Ecological Paradigm (NEP) scale. Both of these theories proved effective in researching the ecological perceptions of and various influences on the participants, with a few minor drawbacks. The data analysis investigated the research questions with a three-pronged approach. Interpersonal interviews and media content analysis of the local and agricultural media in the area was followed by analysing the two sets of findings, in order to find overlaps and relationships between the factors explored. The interviews were designed as semi-structured to allow for themes to emerge and were conducted mainly within the diary and beef industries, consisting of 24 participants. The media content analysis incorporated a niche agricultural magazine (32 articles) as well as the local newspaper (74 articles). The articles were coded for themes to allow for comparison between the two, and to provide an overall understanding of the media coverage. The use of the interviews and media content analysis concurrently, made it possible to determine the farmers’ perceptions of water conservation and the possible influences on these. By exploring this, the research endeavours to understand the dynamics between the farmers’ use of media and interpersonal networks and their water conservation practices. The farmers’ perceptions appeared to be predominantly shaped by agricultural media and interpersonal communities. The NEP scale responses exposed the clash between economic and environmental considerations. The farmers were acutely aware of their ecological impact and were employing various measures to counteract it. However, these were heavily dependent on their financial situation. This is in contrast to the NEP scale’s measuring of NEP statements contrasted with Dominant Social Paradigm (DSP) statements to determine ecological attitudes. These findings confirm previous research and demonstrate that modern farmers are more likely to adopt conservation practices than their traditional counterparts, if it helps achieve their economic, social and environmental goals. The importance of the historical context of South Africa’s water issues emerged, with the past and future proposed changes to water regulation and legislation affecting farmers’ perceptions. The move from agriculturally privileged water legislation to equitable distribution is affecting the farmers negatively, causing distrust towards the government. The research was successful in achieving an understanding of the effect of the mass media and interpersonal communication influences on the farmers’ perceptions of water conservation.
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  • Date Issued: 2016

Men eating meat with students

  • Authors: Male guests , Rhodes University students
  • Date: 2016
  • Subjects: Keiskammahoek (South Africa)
  • Type: Image
  • Identifier: http://hdl.handle.net/10962/220041 , vital:48586 , KHP-191
  • Description: Photograph of Men eating meat with students outdoors. , Use of this resource is governed by the terms and conditions of the Creative Commons "Attribution-NonCommercial-ShareAlike" License (http://creativecommons.org/licenses/by-nc-sa/2.0/)
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  • Date Issued: 2016

Men grouped around a water drum filled with traditional beer

  • Authors: Male family members and guests
  • Date: 2016
  • Subjects: Keiskammahoek (South Africa)
  • Type: Image
  • Identifier: http://hdl.handle.net/10962/219829 , vital:48561 , KHP-192
  • Description: Photograph ofMan posing for a picture with water drum filled with traditional beer and more men in the backgroud. , Use of this resource is governed by the terms and conditions of the Creative Commons "Attribution-NonCommercial-ShareAlike" License (http://creativecommons.org/licenses/by-nc-sa/2.0/)
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  • Date Issued: 2016

Mental stress among civil engineering construction site agents and foremen in the Nelson Mandela Bay Metropole

  • Authors: Haydam, Erich
  • Date: 2016
  • Subjects: Project management -- South Africa -- Nelson Mandela Bay Municipality , Civil engineers -- Job stress -- South Africa -- Nelson Mandela Bay Municipality , Construction industry -- South Africa -- Nelson Mandela Bay Municipality
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10948/5545 , vital:20901
  • Description: The civil engineering sector of the construction industry as a whole has been suffering from mental stress due to a lack of stress management interventions, rendering employees vulnerable to burnout, poor mental health, and subject to injury on site. The rationale of this study is to explore the prevalence of mental stress in the civil engineering sector of the construction industry, and the potential causes of stress, vis-à-vis the effects it has on an individual. An empirical study based on a descriptive and analytical survey method was conducted among medium to large civil engineering contractors in the Nelson Mandela Bay Metropole (NMBM). The study adopted the use of questionnaires, and a review of the related literature to effectively summarise and describe the collected field data. The sample stratum included civil engineering site agents and foremen. The salient findings include: high job demands, low job control, and low job social support are contributors to stress; site agents and foremen long for more time spent with family and friends; site agents and foremen are exposed to various physical, organisational and socio-economic stressors; site agents and foremen are displaying coping strategies unsupportive of a healthy lifestyle; there is a lack of awareness of stress management in the civil engineering sector of the construction industry; the level of stress experienced by site agents and foremen is rated as a lesser extent; the prevalence of depression among site agents and foremen is rated as a lesser extent; site agents and foremen are at risk of injury due to feeling stressed, and site agents and foremen are exposed to a range of musculoskeletal disorders (MSDs) due to poor ergonomics, and possibly stress too. It can be concluded that stress negatively affects the civil engineering sector of the construction industry by, inter alia, increased employee absence, injuries and accidents, higher staff turnover, depression, and lower levels of production. Furthermore, stress may lead to eventual burnout, rendering an individual at a significantly higher risk of developing physical health complications. Recommendations include: organisations to address the problem of work-family imbalance, by providing more time off to spend with family and loved ones. v Organisations need to promote and implement internal coping strategies, to assist those who are facing strain to effectively deal with their stress. More support from line managers to employees should be provided, as this will increase their resources in terms of job support, job demand, and job control in their working environment. Also, organisations need to promote teambuilding activities and exercise among their employees. Lastly, organisational policy and government legislation need to be revised in the long term, to provide for individual mental wellbeing, and reduced occupational stress.
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  • Date Issued: 2016

Mesopredator release and the effectiveness of camera traps for estimating mammal abundances in the Eastern Cape, South Africa

  • Authors: Taylor, Jonathan Michael
  • Date: 2016
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/3587 , vital:20527
  • Description: Remotely operated cameras (camera traps) have become an indispensable tool for many ecologists, particularly those studying rare and elusive animals. A plethora of camera trap makes and models are now commercially available, yet the effects of their varying design features on the quality and quantity of data recorded remains principally unknown. Better understanding of differing camera trap designs is needed before adequate management policies can be implemented, especially when the aim is to protect vulnerable and endangered species such as many carnivores. Habitat loss and human conflict has prompted worldwide declines of apex predator populations. Following this, many smaller predators have undergone population ‘explosions’ due to the lack of top-down forcing, a phenomenon known as mesopredator release. Land use changes in the Eastern Cape of South Africa have caused extensive degradation and fragmentation of the Subtropical Thicket Biome. In addition, coupled with anthropogenic persecution, apex predators including lions (Panthera leo), leopards (P. pardus), and brown hyaenas (Hyaena brunnea) have been extirpated from large areas of their historic range. Removal of these apex predators may provide opportunity for mesopredators, such as black-backed jackals (Canis mesomelas) and caracals (Caracal caracal), to be released from top-down forcing and possibly initiate trophic cascade effects. Therefore, using randomly distributed camera traps, my study aimed to explore the quality and quantity of data collected by different camera trap designs, and to investigate the mesopredator release hypothesis in the Eastern Cape of South Africa. A total of 2,989 trap nights was used to compare camera trap designs. Camera traps with narrow detection zones and fast trigger speeds (≤ 0.25 seconds) recorded a higher diversity of carnivores, but there was no significant difference in the relative abundances of carnivore species recorded by different camera trap models. A total of 19,659 trap nights was used to assess mesopredator relative abundance, occupancy, distribution and daily activity patterns at one site with, and one site without, apex predators. Consistent with the mesopredator release hypothesis, black-backed jackal relative abundance was significantly higher in the absence of apex predators, and this was supported by occupancy analyses. Further, black-backed jackal distribution was significantly concentrated in areas where apex predator activity was low, possibly indicating spatial avoidance. There was no significant difference in caracal relative abundance, occupancy, distribution, or daily activity between sites. These results provide the first indication of mesopredator release of blackbacked jackals in the Eastern Cape. The implications of black-backed jackal release including prey population structure, local extinctions, altered seed dispersal and disease dynamics are discussed.
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  • Date Issued: 2016

Mesoscale mechanisms of larval transport and settlement in relation to physical factors off the south coast of South Africa: a topographic approach

  • Authors: Mian, Shana Iva
  • Date: 2016
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5947 , http://hdl.handle.net/10962/d1020844
  • Description: The majority of benthic marine invertebrate life cycles include a meroplanktonic phase. Most marine biologists recognise that this stage could play an important role in dispersal, especially for sedentary or sessile organisms. Recent studies on larval dispersal have found that dispersal does not occur to the extent that was previously believed. Some larvae instead remain close to their natal populations through larval nearshore retention mechanisms, both active and passive. This study attempted to a) describe nearshore distribution patterns of several intertidal larvae in relation to nearshore hydrodynamics, b) infer whether larvae are active or passive in the water column and whether this differs among taxa and c) compare pelagic mussel larval abundance with settlement rates, at 2 bay and 2 open coast sites on the south coast of South Africa to note any topographical effects. At each of the four sites, pelagic samples were collected along 2 transects. Larvae and current speed data were collected at various depths (surface, mid-depth and bottom) at distances of 200, 400, 900 and 2400m offshore of the coast. Settlement samples were collected at sites that were onshore of the pelagic transects using plastic souring pads following previous studies. Pelagic larval distribution showed no effect of topography. Instead larval abundance was highly variable among sample periods and among different taxa. Slow swimming D-stage mussel larvae were found to be positively correlated with both upwelling and turbulence indices suggesting that they behave as passive particles in the water column. The abundances of larval taxa with faster swimming speeds than the D-larvae were negatively correlated with upwelling and did not correlate with turbulence. This suggests that these larvae are more active within the water column than the D-larvae which would theoretically allow them to maintain their position in the water column. Further analysis revealed that mean larval depth correlated with mean depth of shoreward moving water masses regardless of the state of upwelling. These results suggest that larvae were actively selecting the depth at which they were found presumably in order to associate themselves with shoreward moving currents. This interpretation was supported by ontogenetic patterns in the behaviour of barnacle larvae, the nauplii of which were found further offshore as they aged, and closer onshore again once they reach the faster swimming cyprid stage. Although there was no detectable effect of topography on the abundances of planktonic larvae, the settlement section of this study revealed an effect of topography, with higher settlement and recruitment rates at bay sites than at the open coast sites. Settlement rates were seen to be negatively correlated with turbulence at bay sites but not open coast sites. Recruitment rates for each sample event were positively correlated with upwelling at each site. This study found pelagic larvae to be generally active within the water column which allowed them to remain close to the shore regardless of topography and upwelling/turbulence regimes. Although meaningful correlation analyses between pelagic larval supply and settlement rates could not be conducted due to loss of settlement collectors, settlement rates were affected by local topography with higher settlement and recruitment in bay sites.
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  • Date Issued: 2016

Metaheuristic design: the parametric blueprint of a processing plant

  • Authors: Ley, Braddin
  • Date: 2016
  • Subjects: Architectural design -- Data processing
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10948/38819 , vital:34985
  • Description: Architectural design “folds” deeply into associative logic, which is used to create a system of grammar responsive to a dialect. Within traditional design practices, these associations create themselves through additive logic, thereby making them laborious in their response to any change in the language. The implementation of computers in architectural design was initially considered a mode to overcome this - to automate the design process. Until now, it has primarily only afforded the designer the opportunity to perform repetitive tasks faster than traditional drawing methods, without enhancing any depth to associative parameters. The current state of the architectural discourse has opened itself up to advanced computation and is beginning to use this capacity fully. Using algorithmic logic to instantaneously process and compare multiple conditions, the designer now holds the power to determine which grammars he desires to engage with, which solutions he is required to review and which outcomes he wishes to find. He no longer labours over repetitive and additive tasks; rather, he focuses on reviewing iterative changes in dialect in order to produce a highly responsive and technically comprehensive architectural solution. It is important to note that these changes in dialect can refer to any field of qualitative or quantitative data, such as quantified climatic or census data, or qualities of light and volume, so long as the designer transposes quality into a scaled matrix of values. The author is captivated by both digital technologies and sensory experiences in architecture, guiding this treatise to understand natural phenomena and their complexities - expressly, environmental responses to field conditions. The design response to this research is formulated from an algorithm that devises a fl oor plan layout; the methodology used is from a close-packed perimeter cell network, most notably found in floor plans of industrial architectures, henceforth the design articulates as industrial architecture in a context reactive to this typology. The agrarian town of Patensie lies in a rich valley of agriculture, climate and field conditions, and provides the opportunity for this treatise to develop.
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  • Date Issued: 2016

Midwives' perceptions in KwaZulu-Natal public hospitals regarding their level of competence related to cardiotocography

  • Authors: Maduna, Ntsepiseng Elizabeth
  • Date: 2016
  • Subjects: Midwifery -- South Africa -- KwaZulu-Natal , Fetal heart rate monitoring -- South Africa -- KwaZulu-Natal , Public hospitals -- South Africa -- KwaZulu-Natal
  • Language: English
  • Type: Thesis , Masters , MCur
  • Identifier: http://hdl.handle.net/10948/5698 , vital:20968
  • Description: The primary purpose of CTG is to detect early signs of intrapartum hypoxia and improve foetal outcomes. Intrapartum hypoxia remains the major cause of perinatal deaths mainly in monitored labours. This is attributed to the midwives’ lack of skills in the foetal implementation and interpretation of CTG. Midwives interpret foetal heart rate patterns erroneously hence they fail to detect early signs of severe foetal compromise. Accurate interpretation of CTG is the cornerstone for clinical decision during intra-partum foetal surveillance. Therefore, it is mandatory that midwives are competent in CTG. The purpose of the study was to explore and describe the perceptions of midwives in KwaZulu-Natal public hospitals regarding their level of competence related to the CTG. The purpose of the study was to explore and describe the perceptions of midwives in KwaZulu-Natal public hospitals regarding their level of competence related to the CTG. The objectives of this study were: -to explore and describe the perceptions of the midwives regarding their level of competence relating to cardiotocography. -to establish the levels of competence of midwives in relation to CTG. -to develop clinical guidelines that could be utilised by midwives in the implementation and interpretation of the cardiotocograph. The study utilised a quantitative non-experimental comparative descriptive research design. A self-developed and self-administered questionnaire was developed under the supervision of a statistician and was to collect data from a purposively selected sample of midwives who work in labour wards in Kwa-Zulu Natal public hospitals. A sample of 226 practicing midwives working in labour wards of the nine KZN public hospitals was selected using a non-probability convenience sampling method; only 125 responded. Data were collected on an excel spread sheet and analysed under the supervision of the statistician and research supervisor. The researcher assured of validity and reliability of the data collection method and data as well as of the data collection instrument. The findings revealed that the midwives in KZN public hospitals perceived themselves as being competent regarding CTG tasks; however they lack knowledge and skills in the implementation and interpretation of CTG. It was also evident that the midwives’ years of midwifery clinical experience, labour ward experience, possession of additional post basic midwifery qualification and the perceived level of competence related to CTG tasks number of years of the midwives did not influence their level of competence in the implementation and interpretation of CTG. Literature control supported these findings and there was consistency with that literature. Recommendations were made and clinical guidelines were developed to assist midwives with the assessment of foetal heart rate and the interpretation of the cardiotocograph results.
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  • Date Issued: 2016

Miscellaneous provisions

  • Authors: Arendse, Jacqueline A , Clegg, David , Williams, Robert C
  • Date: 2016
  • Subjects: To be catalogued
  • Language: English
  • Type: text , book chapter
  • Identifier: http://hdl.handle.net/10962/131276 , vital:36548 , https://store.lexisnexis.co.za/products/silke-on-tax-administration-skuZASKUPG1440
  • Description: Miscellaneous provisions pertaining to tax administration are explained in this chapter.
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  • Date Issued: 2016

Misfits in the margins transgression and transformation on the (South) African frontier

  • Authors: Van Wyk Smith, Malvern
  • Date: 2016
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/458282 , vital:75729 , https://hdl.handle.net/10520/EJC190705
  • Description: The story of the European encounter with Africa includes many liminal characters who mostly play little part in the larger sweep of events but everywhere suggest alternative scenarios that might have developed, or at least discordant readings of what did actually happen. They range from the Khoi interpreter Coree, who was taken to England in 1614, to a group of London women sent to Sierra Leone in the 1790s to marry local slave traders, or from various Cape avatars of Shakespeare's Caliban to several picturesque originals for Defoe's African eccentrics; from early African articulants of African independence and dignity, such as the Prince Naimbanna of Sierra Leone, to many intriguing individuals (both African and European) who emerge from the records of Portuguese shipwrecks along the southern African coast and the sixteenth-century Portuguese penetration of south-east Africa. Nor is the story short on the occasional African Queen and Sable Venus who not only enliven events but at times impact significantly on the developing politics of colonialism.
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  • Date Issued: 2016

Mitigation of the effect of father imprisonment on the family: a study of social work intervention strategies in Raymond Mhlaba local municipality

  • Authors: Tshaka, Akhona
  • Date: 2016
  • Subjects: Social work with single parents Single mothers -- South Africa -- Eastern Cape Single parents -- South Africa -- Eastern Cape Single-parent families -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , Degree
  • Identifier: http://hdl.handle.net/10353/4435 , vital:28334
  • Description: The South African population is highly populated by single mothered families. Fatherlessness has emerged as one of the greatest social problems, especially as children who grow up in families with absent-fathers suffer lasting damage. The aim of this study was to examine the effect of fathers’ imprisonment on the functioning of the family and social work interventions to mitigate the effect. The study used mixed method research design. Data was collected through the use of questionnaires and in-depth interviews. This study employed three sampling strategies; namely multi-stage sampling and purposive sampling as well as snow-ball sampling. The sample was made up of 65 members of families whose father is in prison or had been to prision and 15 social work officials. Qalitative data was analyised using themes and parrtens that emerged during interviews with participants, quantitative data was analysed using SPSS computer softerwere. Findings revealed that father’s imprisonment has negative impact that causes dysfunctional families. The negative effect is due to the loss of a father figure and a provider of the family. Inequality and stigmatisation among family members were also found to cause dysfunctional families after the father’s imprisonment. Findings from social work officials revealed social service interventions to mollify the family dysfunctions. However, majority of families are provided services through offender re-integration, others lack unawareness regarding social work interventions for families with fathers in prison. Findings further reveal that resources are limited to enhance the provision of adequate and better psychosocial support for affected families in order to alleviate the undesirable impact of father’s imprisonment. There is therefore a compelling need for implementing policies that will enable dysfunctional families with fathers imprison to access adequate psychosocial support services. The study also recommended that, social welfare system should be strengthened by embarking on enlightenment programmes that create awareness about family based interventions for dysfunction families with fathers in prison.
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  • Date Issued: 2016

Modelling dispersal processes in impala-cheetah-lion ecosystems with infection in the lions

  • Authors: Mbava, Willard
  • Date: 2016
  • Subjects: Predation (Biology) -- South Africa -- Kruger National Park Endangered species -- South Africa -- Kruger National Park
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/11782 , vital:26968
  • Description: The study involved the predator-prey interaction of three species namely the predator (Cheetah Acinonyx jubatus), the super-predator (Lion Panthera leo), and their common prey (Impala Aepyceros melampus). The study area is the Kruger National Park. The predator being an endangered species, faces a survival problem. It is frequently killed by the super-predator to reduce competition for prey. The super-predator also scares away the predator o_ its kills. The prey forms the main diet of the predator. The plight of the predator motivated the author to formulate disease and reaction-diffusion models for the species interactions. The purpose of the models were to predict and explain the effect of large competition from the super-predator on the predator population. Important parameters related to additional predator mortality due to presence of super-predator, the disease incidence rate and induced death rate formed the focal points of the analysis. The dynamics of a predator-prey model with disease in super-predator were investigated. The super-predator species is infected with bovine Tuberculosis. In the study, the disease is considered as biological control to allow the predator population to regain from low numbers. The results highlight that in the absence of additional mortality on the predator by the super-predator, the predator population survives extinction. Furthermore, at current levels of disease incidence, the super-predator population is wiped out by the disease. However, the super-predator population survives extinction if the disease incidence rate is low. Persistence of all populations is possible in the case of low disease incidence rate and no additional mortality imparted on the predator. Furthermore, a two-species subsystem, prey and predator, is considered as a special case to determine the effect of super-predator removal from the system, on the survival of the predator. This is treated as a contrasting case from the smaller parks. The results show that the predator population thrives well in the total absence of its main competitor, with its population rising to at least twice the initial value. A reaction-diffusion three-species predator-prey model was formulated and analysed. Stability of the temporal and the spatio-temporal systems, existence and non-existence of stationary steady state solutions were studied. Conditions for the emergence of stationary patterns were deduced. The results show that by choosing the diffusion coeffcient d2 > _D 2 suffciently large, a non-constant positive solution is generated, that is, stationary patterns emerge, depicting dispersal of species. Predators were observed to occupy habitats surrounding prey. However, super-predators were observed to alternate their habitats, from staying away from prey to invading prey habitat. In the investigation, strategies to determine ways in which the predator species could be saved from extinction and its population improved were devised, and these included isolation of the predator from the super-predator.
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  • Date Issued: 2016

Modelling transport of inshore and deep-spawned chokka squid (Loligo reynaudi) paralarvae off South Africa: the potential contribution of deep spawning to recruitment

  • Authors: Downey-Breedt, Nicola , Roberts, Michael J , Sauer, Warwick H H , Chang, N
  • Date: 2016
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/125183 , vital:35742 , https://doi.10.1111/fog.12132
  • Description: The South African chokka squid, Loligo reynaudi, spawns both inshore (≤70 m) and on the mid-shelf (71–130 m) of the Eastern Agulhas Bank. The fate of these deep-spawned hatchlings and their potential contribution to recruitment is as yet unknown. Lagrangian ROMS-IBM (Regional Ocean Modelling System-Individual-Based Model) simulations confirm westward transport of inshore and deep-spawned hatchlings, but also indicate that the potential exists for paralarvae hatched on the Eastern Agulhas Bank deep spawning grounds to be removed from the shelf ecosystem. Using a ROMS-IBM, this study determined the transport and recruitment success of deepspawned hatchlings relative to inshore-hatched paralarvae. A total of 12 release sites were incorporated into the model, six inshore and six deep-spawning sites. Paralarval survival was estimated based on timely transport to nursery grounds, adequate retention within the nursery grounds and retention on the Agulhas Bank shelf. Paralarval transport and survival were dependent on both spawning location and time of hatching. Results suggest the importance of the south coast as a nursery area for inshore-hatched paralarvae, and similarly the cold ridge nursery grounds for deep-hatched paralarvae. Possible relationships between periods of highest recruitment success and spawning peaks were identified for both spawning habitats. Based on the likely autumn increase in deep spawning off the Tsitsikamma coast, and the beneficial currents during this period (as indicated by the model results) it can be concluded that deep spawning may at times contribute significantly to recruitment.
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  • Date Issued: 2016

Modular electric automatic guided vehicle suspension-drive unit

  • Authors: Macfarlane, Alexander Blair Stuart , Van Niekerk, Theo
  • Date: 2016
  • Subjects: Autonomous vehicles , Sustainable design
  • Language: English
  • Type: Thesis , Masters , MEng
  • Identifier: http://hdl.handle.net/10948/8220 , vital:25968
  • Description: This report discusses the design, development, elevation and creation of a modular omni-directional suspension-drive train unit for use on 1000 kg automatic guided vehicle. The system included a semi-active suspension oleo strut system that can vary its dampening and ride height. The drive train system is capable of omni-directional motion through the use of separately driven mechanum wheels power by a 48 volt DC system.
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  • Date Issued: 2016

Molecular characterization of Mycobacterium bovis isolated from cattle and sputum specimens from humans in the Eastern Cape province, South Africa : public health and economic implication

  • Authors: Bhembe, Nolwazi Londiwe
  • Date: 2016
  • Subjects: Mycobacterium tuberculosis -- South Africa -- Eastern Cape Public health -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10353/13238 , vital:39625
  • Description: Tuberculosis (TB) is a disease caused by the members of the Mycobacterium tuberculosis complex (MTBC), which infects both animals and humans. The primary host of Mycobacterium bovis is cattle. It remains a major global health problem. About 2 billion people are thought to be infected with TB and about 1.3 million decease each year from the disease. This study is aimed at determining the prevalence of the disease, characterizing the MTBC isolates and increasing the understanding of the genetic diversity MTBC in the Eastern Cape Province of South Africa, from studying both samples from both humans and cattle. A total of 376 cattle lymph nodes were collected from two commercial abattoirs for investigations. Suspected 6 000 sputum specimens were also collected from humans (cattle farmers). All collected samples were cultured, and isolates were confirmed with a multiplex polymerase chain reaction (PCR) targeting the mpb64 and IS6110 genes. Positive isolates were tested for resistance against anti-TB drugs using the standard Lowenstein Jensen proportion method. Isolates from cattle lymph nodes were further characterized to species level, using the region of deletion 1 (RD1) and oxyR restriction fragment length polymorphism analyses. MIRU-VNTR typing and spoligotyping assays were used to further examine the genetic diversity of all strains. Obtained spoligotype patterns were matched with isolates published in the universal spoligotyping database (SITVIT2). MTBC was detected in 162 (43.09 percent) cattle lymph nodes and 156 sputum specimens. Some isolates 25.9 percent (42/162) from the cattle lymph nodes samples were resistant to rifampicin (RIF) and 98.7 percent (154/156) were resistant to isoniazid (INH) and rifampicin (RIF) (of the human sputum specimens). All cattle lymph nodes isolates exhibited the RD1 gene, and the oxyR analyses classified 96.9 percent of the isolates as Mycobacterium tuberculosis complex and 3.1 percent as Mycobacterium bovis. Twenty seven spoligotype patterns were isolated from cattle lymph nodes, with 10 shared types (SIT) consigned to 5 lineages, including Bov_4-Caprea (1.9 percent), Microti (0.6 percent) and Beijing (17.9 percent) constituting East Asian, Latin-American-Mediterranean (LAM) (3.7 percent), X (4.3 percent), MANU (3.1percent), S (0.6 percent) and 67.9 percent were orphans that were further categorized to their designated lineages (Indo-Oceanic, Euro-American and West-African 2). Ninety one percent of the isolates from humans (farmers) were grouped into 7 clusters by spoligotyping, while the remaining 9 percent was unclustered. SITs were observed in 89.6 percent of the isolates from the Beijing, LAM, X, T and S families. The Beijing family was the most prevalent strain from both human isolates (77.2 percent) and cattle lymph nodes isolates (17.9 percent), and the T (0.6 percent) and Microti (0.6 percent) families were the least detected genotypes in both humans and cattle lymph nodes. In the cattle lymph nodes, spoligotyping showed a higher clustering rate of 82.1 percent, with the lowest (HGDI) = 0.485. The 12 MIRU-VNTR clustering rate was 64.8 percent, showing a higher HGDI of 0.671. However, a combination of both methods showed a decreased clustering rate of 53.7 percent; however these methods resulted in a higher HGDI (0.676). Isolates from human sputum specimens spoligotyping showed a higher clustering rate of 89 percent with an HGDI = 0.822. The 12 MIRU-VNTR showed the lowest clustering rate of 69 percent and an HGDI = 0.940 and the combination of the methods showed a clustering rate of 78 percent and an HGDI = 0.951. The results of this study show the diversity of MTBC strains in the Eastern Cape Province and the low clustering rate indicates continuing transmission in the province. The detection of MTBC strains from slaughtered cattle lymph nodes in abattoirs confirms the risk of providing TB infected meat in markets which has serious implications for the control of TB in South Africa. The continuing spread of MTBC in South Africa threatens both the public and economic health.
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  • Date Issued: 2016

Molecular genetic, life-history and morphological variation in a coastal warm-temperate sciaenid fish: evidence for an upwelling-driven speciation event

  • Authors: Henriques, Romina , Potts, Warren M , Sauer, Warwick H H , Santos, Carmen V D , Kruger, Jerraleigh , Thomas, Jessica A , Shaw, Paul W
  • Date: 2016
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/125252 , vital:35750 , http://dx.doi.10.1111/jbi.12829
  • Description: The marine environment is punctuated by biogeographical barriers that limit dispersal and gene flow in otherwise widespread species (Teske et al., 2011a,b; Briggs & Bowen, 2012; Luiz et al., 2012). These barriers may be physical obstacles such as landmasses (e.g. Isthmus of Panama) or less intuitive features such as deep water (Lessios et al., 2003), freshwater outflows (Floeter et al., 2008) or oceanographic features (Shaw et al., 2004; Galarza et al., 2009; von der Heyden et al., 2011). Upwelling cells and sea surface temperature (SSTs) gradients in particular are known to disrupt gene flow, leading to divergence of allopatric populations and species (Waters & Roy, 2004; Teske et al., 2011a; Henriques et al., 2012, 2014, 2015). However, as oceanographic features are seldom permanent and frequently subject to considerable environmental variability, many barriers often permit some level of permeability to dispersal (Floeter et al., 2008). Other processes may influence the persistence of differentiated allopatric taxa across such physical barriers (Bradbury et al., 2008), with ecological divergence (and diversifying selection) being reported as a major evolutionary process influencing the biogeographical distributions of marine species (Pelc et al., 2009; Teske et al., 2011a; Gaither et al., 2015).
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  • Date Issued: 2016

Molecular identification of Azolla invasions in Africa: The Azolla specialist, Stenopelmus rufinasus proves to be an excellent taxonomist

  • Authors: Madeira, P T , Dray, F Allen , Coetzee, Julie A , Paterson, Iain D , Tipping, Philip W
  • Date: 2016
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/424765 , vital:72182 , xlink:href="https://doi.org/10.1016/j.sajb.2016.03.007"
  • Description: Biological control of Azolla filiculoides in South Africa with the Azolla specialist Stenopelmus rufinasus has been highly successful. However, field surveys showed that the agent utilized another Azolla species, thought to be the native Azolla pinnata subsp. africana, which contradicted host specificity trials. It is notoriously difficult to determine Azolla species based on morphology so genetic analyses were required to confirm the identity of the Azolla used by the agent. Extensive sampling was conducted and samples were sequenced at the trnL-trnF and trnG-trnR chloroplastic regions and the nuclear ITS1 region. Current literature reported A. filiculoides as the only Section Azolla species in southern Africa but 24 samples were identified as Azolla cristata, an introduced species within Section Azolla that was not used during host specificity trials. A. pinnata subsp. africana was only located at one site in southern Africa, while the alien A. pinnata subsp. asiatica was located at three. What was thought to be A. pinnata subsp. africana was in fact A. cristata, a closer relative of A. filiculoides and a suitable host according to specificity trials. This study confirms that S. rufinasus is a proficient Azolla taxonomist but also supports the use of molecular techniques for resolving taxonomic conundrums.
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  • Date Issued: 2016

Mongrel: essays, William Dicey

  • Authors: Wylie, Dan
  • Date: 2016
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/142748 , vital:38113 , https://www.ajol.info/index.php/tvl/article/view/143393
  • Description: If I had the liberty to run an introductory course on South African history, I might well start with William Dicey’s Borderline (2004). Borderline recounts Dicey and some friends’ canoe trip down the Orange River, from Orania to the sea. It’s by turns lyrical and funny, and rich with historical perspectives stimulated by people and places Dicey encounters en route.
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  • Date Issued: 2016

Monitoring changes in vegetation distribution to ascertain the extent of degradation in the savannas of Nkonkobe Local Municipality, Eastern Cape, South Africa

  • Authors: Masiza, Wonga
  • Date: 2016
  • Subjects: Savanna ecology -- South Africa -- Eastern Cape Land degradation -- South Africa -- Eastern Cape Vegetation management -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10353/2027 , vital:27598
  • Description: Savanna degradation is an environmental problem occurring in most countries around the world and it poses threats to biodiversity conservation, the food industry, and other economic sectors. According to FAO, South Africa’s rangelands exhibit the highest rate of fragmentation in comparison to range ecosystems in neighbouring countries including Lesotho and Swaziland, and consensus among researchers is that communal rangelands are more degraded than commercial rangelands. Although researchers and communities have identified the occurrence of land degradation in communal savannas at a local scale, land degradation has been poorly estimated because little has been done to quantify the extent and dynamics of perceived and observed changes associated with land degradation. The main goal of this study is to provide empirical insights on the direction of changes in the communal savannas of Nkonkobe Local Municipality in order to inform policy formulation and implementation. Additional to the communal sites is a private farm included for comparative analysis of trends in communal and commercial savannas. Landsat imagery was used to map, assess, and quantify the extent of land degradation in Nkonkobe Local Municipality, over a period of 30 years between 1984 and 2014. Field investigations were undertaken in June 2015 to acquire reference data to guide supervised classification of Landsat images. Three algorithms (Mahalanobis-distance, Minimum-distance, and Maximum likelihood classification) were compared to identify a classifier that produced the best results. The maximum likelihood classifier produced the best results with classification accuracy levels of 95.24 percent, 89.66 percent, and 95.65 percent for Honeydale Farm, Thyume, and Sheshegu respectively. Regression analysis revealed that both communal and private lands have experienced statistically significant increases in bush encroachment and decreases in surface water. Communal savannas have been confronted more by expansion of built-up area, decrease in open grassland, abandonment of arable land, soil erosion, and a steady invasion by Acacia Karroo compared to the privately owned commercial farm. The land cover changes measured through this investigation suggest an environmental shift that threatens biodiversity and agricultural activity. The study provides empirically informed insights about the direction to which these savannas are changing with the hope that the findings will prompt formulation and implementation of effective policies.
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  • Date Issued: 2016
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