Geology, regional diamond exploration and diamond provenance of the proterozoic diamondiferous Umkondo conglomerates, Umkondo group, eastern Zimbabwe
- Authors: Zhou, Takawira
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3598 , vital:20528
- Description: The Umkondo Sedimentary Basin in eastern Zimbabwe has been studied by various individuals and organizations since 1901. Their interest had been in finding limestone and beryl and base metal deposits, especially copper, iron and uranium, but these occurrences had proved to be of no economic value (Watson, 1969). The recent discovery of placer diamonds within the Proterozoic basal conglomerates of the Umkondo Sedimentary Basin has now attracted worldwide interest in the basin’s diamond economic potential, in understanding of the geology, and the diamond provenance of the Umkondo conglomerates. The Umkondo Sedimentary Basin basal conglomerate placer deposit might narrowly be defined as a mega-placer because of its sheer large size and high grades, especially on the 70,000 hectare western margin diamond dispersion halo where alluvial diamonds are being mined. Bluck, et al., (2005, pp 213) defines a diamond mega-placer as: . . . a number of linked deposits that are a result of one or a continuous process of transportation and deposition and holds or have held at least >= 50 million carats at >= 95% gem quality, for example, the Orange-Vaal dispersal, off the Kaapvaal craton in South Africa. On craton placers are residual, and transient placers are eroded and deposited into the exit drainage, while terminal placers, the final depositories of diamonds with the highest chances of being mega-placers are deposited into terminal basins like oceans and foreland basins. Though data is limited at the moment, the Umkondo conglomerates caratage is likely to run into hundreds of millions of carats, with a diamond gem content of between twenty and twenty-five percent, as is indicated from recent diamond production data. The greater part of the Umkondo diamonds are likely to be lodged beneath the deep gravels of the Middle and Lower Save River basin, because small remnant tilted mountain blocks and inselbergs forming the caps of hills are what remains of the host conglomerate on the western margin of the Umkondo Basin. Areas to be examined in this document will be the geology; the mode of formation of the Umkondo basin and its sedimentary system; the regional kimberlite exploration around the basin; and diamond production in the Marange diamond field, in order to come up with indications of the provenance of the diamonds within the Umkondo conglomerates. The kimberlite clusters in and around the Umkondo sedimentary basin have all proved to be barren or only nominally diamondiferous and that the kimberlites are between 200Ma and 500Ma and thus much younger than the greater than 1.1Ga Umkondo diamondiferous conglomerates. Studies so far undertaken have not managed to point to the origin, or provenance, of the Umkondo or Marange diamonds, which were discovered on the western edge of the Umkondo Basin and in the east of the basin below the Chimanimani Mountains along the Haroni River. This paper is an attempt to clear up some of the misconceptions surrounding the Marange diamond deposit and to raise interest in the urgent rquirement to study and understand the Umkondo Basin and the origin of its diamonds. The only meaningful studies on diamond occurrence and diamond exploration of the basin were undertaken from 1996 to 2006 by Kimberlitic Searches Zimbabwe (Pvt) Ltd, the then Zimbabwe kimberlite exploration arm of De Beers, Zimbabwe, in their quest to find kimberlites, which were thought to be related to the Umkondo alluvial diamond deposit. As will be shown in the following chapters, many of the discovered kimberlites range from very low grade to non-diamondiferous, and are much younger than the Umkondo conglomerates, whose diamonds are in turn a great deal older. Thus the basic question concerning the origin or provenance of the Umkondo placer diamonds still remains unresolved. Because of the sheer size of the basin, modern, wide-area-coverage, geophysical exploration methods become appropriate to effectively generate diamond potential targets for further examination. This document will attempt to collate various data available to paint a true picture of the state of exploration within the Umkondo Basin.
- Full Text:
- Date Issued: 2016
- Authors: Zhou, Takawira
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3598 , vital:20528
- Description: The Umkondo Sedimentary Basin in eastern Zimbabwe has been studied by various individuals and organizations since 1901. Their interest had been in finding limestone and beryl and base metal deposits, especially copper, iron and uranium, but these occurrences had proved to be of no economic value (Watson, 1969). The recent discovery of placer diamonds within the Proterozoic basal conglomerates of the Umkondo Sedimentary Basin has now attracted worldwide interest in the basin’s diamond economic potential, in understanding of the geology, and the diamond provenance of the Umkondo conglomerates. The Umkondo Sedimentary Basin basal conglomerate placer deposit might narrowly be defined as a mega-placer because of its sheer large size and high grades, especially on the 70,000 hectare western margin diamond dispersion halo where alluvial diamonds are being mined. Bluck, et al., (2005, pp 213) defines a diamond mega-placer as: . . . a number of linked deposits that are a result of one or a continuous process of transportation and deposition and holds or have held at least >= 50 million carats at >= 95% gem quality, for example, the Orange-Vaal dispersal, off the Kaapvaal craton in South Africa. On craton placers are residual, and transient placers are eroded and deposited into the exit drainage, while terminal placers, the final depositories of diamonds with the highest chances of being mega-placers are deposited into terminal basins like oceans and foreland basins. Though data is limited at the moment, the Umkondo conglomerates caratage is likely to run into hundreds of millions of carats, with a diamond gem content of between twenty and twenty-five percent, as is indicated from recent diamond production data. The greater part of the Umkondo diamonds are likely to be lodged beneath the deep gravels of the Middle and Lower Save River basin, because small remnant tilted mountain blocks and inselbergs forming the caps of hills are what remains of the host conglomerate on the western margin of the Umkondo Basin. Areas to be examined in this document will be the geology; the mode of formation of the Umkondo basin and its sedimentary system; the regional kimberlite exploration around the basin; and diamond production in the Marange diamond field, in order to come up with indications of the provenance of the diamonds within the Umkondo conglomerates. The kimberlite clusters in and around the Umkondo sedimentary basin have all proved to be barren or only nominally diamondiferous and that the kimberlites are between 200Ma and 500Ma and thus much younger than the greater than 1.1Ga Umkondo diamondiferous conglomerates. Studies so far undertaken have not managed to point to the origin, or provenance, of the Umkondo or Marange diamonds, which were discovered on the western edge of the Umkondo Basin and in the east of the basin below the Chimanimani Mountains along the Haroni River. This paper is an attempt to clear up some of the misconceptions surrounding the Marange diamond deposit and to raise interest in the urgent rquirement to study and understand the Umkondo Basin and the origin of its diamonds. The only meaningful studies on diamond occurrence and diamond exploration of the basin were undertaken from 1996 to 2006 by Kimberlitic Searches Zimbabwe (Pvt) Ltd, the then Zimbabwe kimberlite exploration arm of De Beers, Zimbabwe, in their quest to find kimberlites, which were thought to be related to the Umkondo alluvial diamond deposit. As will be shown in the following chapters, many of the discovered kimberlites range from very low grade to non-diamondiferous, and are much younger than the Umkondo conglomerates, whose diamonds are in turn a great deal older. Thus the basic question concerning the origin or provenance of the Umkondo placer diamonds still remains unresolved. Because of the sheer size of the basin, modern, wide-area-coverage, geophysical exploration methods become appropriate to effectively generate diamond potential targets for further examination. This document will attempt to collate various data available to paint a true picture of the state of exploration within the Umkondo Basin.
- Full Text:
- Date Issued: 2016
A mathematical study on optimal prevention and control strategies for tuberculosis: case study for Port Elizabeth, South Africa
- Authors: Zembe, Pumelela Vincent
- Date: 2016
- Subjects: Tuberculosis -- South Africa -- Port Elizabeth -- Prevention Tuberculosis -- Mathematical models , Tuberculosis -- Case studies
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/12823 , vital:27124
- Description: In this treatise a SEIR model for the transmission of tuberculosis was proposed. It assumes that the latent infected individuals progress to active tuberculosis through endogenous reactivation and exogenous re-infection and that the individuals who have recovered from the disease through treatment are not immune to tuberculosis re-infection. While most features of the original model were kept, the model was modified to incorporate two control measures in the form of post-exposure tuberculosis prophylaxis for the treatment of latent individuals and tuberculosis therapeutics for the treatmentof individuals with active tuberculosis. Mathematical analysis of the modelwas done under the assumption that the two control measures are positiveconstants. The disease-free equilibrium point was locally asymptotically stable when the basic reproduction number was less than unity and unstable when this epidemic threshold exceeds unity. An optimal control problem was formulated and the necessary conditions for optimality were derived.The numerical results based on data from Port Elizabeth suggest that using both forms of control measures simultaneously is more effective in reducing the total number of infected individuals than applying single controls separately.
- Full Text:
- Date Issued: 2016
- Authors: Zembe, Pumelela Vincent
- Date: 2016
- Subjects: Tuberculosis -- South Africa -- Port Elizabeth -- Prevention Tuberculosis -- Mathematical models , Tuberculosis -- Case studies
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/12823 , vital:27124
- Description: In this treatise a SEIR model for the transmission of tuberculosis was proposed. It assumes that the latent infected individuals progress to active tuberculosis through endogenous reactivation and exogenous re-infection and that the individuals who have recovered from the disease through treatment are not immune to tuberculosis re-infection. While most features of the original model were kept, the model was modified to incorporate two control measures in the form of post-exposure tuberculosis prophylaxis for the treatment of latent individuals and tuberculosis therapeutics for the treatmentof individuals with active tuberculosis. Mathematical analysis of the modelwas done under the assumption that the two control measures are positiveconstants. The disease-free equilibrium point was locally asymptotically stable when the basic reproduction number was less than unity and unstable when this epidemic threshold exceeds unity. An optimal control problem was formulated and the necessary conditions for optimality were derived.The numerical results based on data from Port Elizabeth suggest that using both forms of control measures simultaneously is more effective in reducing the total number of infected individuals than applying single controls separately.
- Full Text:
- Date Issued: 2016
The influence of aspirations on changing livelihood strategies in rural households of Ndabakazi villages in the Eastern Cape
- Authors: Zantsi, Siphe
- Date: 2016
- Subjects: Households -- Economic aspects -- South Africa -- Eastern Cape Rural development projects -- South Africa -- Eastern Cape Sustainable development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5653 , vital:29357
- Description: The objective of this study is to explore the role of aspirations on changing livelihood strategies of rural households of Ndabakazi villages in the Eastern Cape. A sample of 80 respondents was chosen randomly for the household survey and semi-structured questionnaires were used to collect the data. Focus group discussions were also used to supplement the household survey. The data was descriptively analysed using a triangulation method. The findings show that social grants, mainly pensions and non-farm employment, and child support grants are the major sources of income. The majority of the households own five hectares of land and more, in which they grow crops only in gardens adjacent to their homes. However, 29 percent do not produce any crops at all. Farming contributes a small portion to the household income. The choice of farming is more powerful than the external factors. Interest in farming is minimal and can be related to the declining farming activities; therefore, household aspirations have an influence on changing livelihood aspirations. In the case of the rural areas of Ndabakazi – as indeed in many other parts of South Africa - policies of rural development mostly take a top-down approach; as a result most of these policies do not become effective in achieving the intended outcome. Development practitioners should incorporate beneficiaries when planning so as to tailor the development initiatives with the aspirations of local people for them to be effect and achieve intended goals thus a bottom-up approach. The notion that rural household farming activities have declined because they lack inputs, farming implements other necessary support is not always true. Some households are not interested in farming and they cannot be forced.
- Full Text:
- Date Issued: 2016
- Authors: Zantsi, Siphe
- Date: 2016
- Subjects: Households -- Economic aspects -- South Africa -- Eastern Cape Rural development projects -- South Africa -- Eastern Cape Sustainable development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5653 , vital:29357
- Description: The objective of this study is to explore the role of aspirations on changing livelihood strategies of rural households of Ndabakazi villages in the Eastern Cape. A sample of 80 respondents was chosen randomly for the household survey and semi-structured questionnaires were used to collect the data. Focus group discussions were also used to supplement the household survey. The data was descriptively analysed using a triangulation method. The findings show that social grants, mainly pensions and non-farm employment, and child support grants are the major sources of income. The majority of the households own five hectares of land and more, in which they grow crops only in gardens adjacent to their homes. However, 29 percent do not produce any crops at all. Farming contributes a small portion to the household income. The choice of farming is more powerful than the external factors. Interest in farming is minimal and can be related to the declining farming activities; therefore, household aspirations have an influence on changing livelihood aspirations. In the case of the rural areas of Ndabakazi – as indeed in many other parts of South Africa - policies of rural development mostly take a top-down approach; as a result most of these policies do not become effective in achieving the intended outcome. Development practitioners should incorporate beneficiaries when planning so as to tailor the development initiatives with the aspirations of local people for them to be effect and achieve intended goals thus a bottom-up approach. The notion that rural household farming activities have declined because they lack inputs, farming implements other necessary support is not always true. Some households are not interested in farming and they cannot be forced.
- Full Text:
- Date Issued: 2016
Detecting derivative malware samples using deobfuscation-assisted similarity analysis
- Authors: Wrench, Peter Mark
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/383 , vital:19954
- Description: The overwhelming popularity of PHP as a hosting platform has made it the language of choice for developers of Remote Access Trojans (RATs or web shells) and other malicious software. These shells are typically used to compromise and monetise web platforms by providing the attacker with basic remote access to the system, including _le transfer, command execution, network reconnaissance, and database connectivity. Once infected, compromised systems can be used to defraud users by hosting phishing sites, performing Distributed Denial of Service attacks, or serving as anonymous platforms for sending spam or other malfeasance. The vast majority of these threats are largely derivative, incorporating core capabilities found in more established RATs such as c99 and r57. Authors of malicious software routinely produce new shell variants by modifying the behaviours of these ubiquitous RATs, either to add desired functionality or to avoid detection by signature-based detection systems. Once these modified shells are eventually identified (or additional functionality is required), the process of shell adaptation begins again. The end result of this iterative process is a web of separate but related shell variants, many of which are at least partially derived from one of the more popular and influential RATs. In response to the problem outlined above, the author set out to design and implement a system capable of circumventing common obfuscation techniques and identifying derivative malware samples in a given collection. To begin with, a decoder component was developed to syntactically deobfuscate and normalise PHP code by detecting and reversing idiomatic obfuscation constructs, and to apply uniform formatting conventions to all system inputs. A unified malware analysis framework, called Viper, was then extended to create a modular similarity analysis system comprised of individual feature extraction modules, modules responsible for batch processing, a matrix module for comparing sample features, and two visualisation modules capable of generating visual representations of shell similarity. The principal conclusion of the research was that the deobfuscation performed by the decoder component prior to analysis dramatically improved the observed levels of similarity between test samples. This in turn allowed the modular similarity analysis system to identify derivative clusters (or families) within a large collection of shells more accurately. Techniques for isolating and re-rendering these clusters were also developed and demonstrated to be effective at increasing the amount of detail available for evaluating the relative magnitudes of the relationships within each cluster.
- Full Text:
- Date Issued: 2016
- Authors: Wrench, Peter Mark
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/383 , vital:19954
- Description: The overwhelming popularity of PHP as a hosting platform has made it the language of choice for developers of Remote Access Trojans (RATs or web shells) and other malicious software. These shells are typically used to compromise and monetise web platforms by providing the attacker with basic remote access to the system, including _le transfer, command execution, network reconnaissance, and database connectivity. Once infected, compromised systems can be used to defraud users by hosting phishing sites, performing Distributed Denial of Service attacks, or serving as anonymous platforms for sending spam or other malfeasance. The vast majority of these threats are largely derivative, incorporating core capabilities found in more established RATs such as c99 and r57. Authors of malicious software routinely produce new shell variants by modifying the behaviours of these ubiquitous RATs, either to add desired functionality or to avoid detection by signature-based detection systems. Once these modified shells are eventually identified (or additional functionality is required), the process of shell adaptation begins again. The end result of this iterative process is a web of separate but related shell variants, many of which are at least partially derived from one of the more popular and influential RATs. In response to the problem outlined above, the author set out to design and implement a system capable of circumventing common obfuscation techniques and identifying derivative malware samples in a given collection. To begin with, a decoder component was developed to syntactically deobfuscate and normalise PHP code by detecting and reversing idiomatic obfuscation constructs, and to apply uniform formatting conventions to all system inputs. A unified malware analysis framework, called Viper, was then extended to create a modular similarity analysis system comprised of individual feature extraction modules, modules responsible for batch processing, a matrix module for comparing sample features, and two visualisation modules capable of generating visual representations of shell similarity. The principal conclusion of the research was that the deobfuscation performed by the decoder component prior to analysis dramatically improved the observed levels of similarity between test samples. This in turn allowed the modular similarity analysis system to identify derivative clusters (or families) within a large collection of shells more accurately. Techniques for isolating and re-rendering these clusters were also developed and demonstrated to be effective at increasing the amount of detail available for evaluating the relative magnitudes of the relationships within each cluster.
- Full Text:
- Date Issued: 2016
Identification of potential novel roles for Hsp70/Hsp90 organising protein (Hop) using proteomic analysis in human cells
- Authors: Wingate, Ianthe
- Date: 2016
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/64758 , vital:28598
- Description: Expected release date-May 2018
- Full Text:
- Date Issued: 2016
- Authors: Wingate, Ianthe
- Date: 2016
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/64758 , vital:28598
- Description: Expected release date-May 2018
- Full Text:
- Date Issued: 2016
Improved singlet oxygen generation by a novel bodipy dye and a study of upconverison nanoparticles mixed with a functionalized bodipy compound
- Wildervanck, Martijn Johannes
- Authors: Wildervanck, Martijn Johannes
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3718 , vital:20538
- Description: This research explores the use of the versatile 4,4-difluoro-4-boro-3a,4a-diaza-s-indacene (BODIPY) dyes and the modification of their spectroscopic properties. The synthesis of a tetramethyl-BODIPY bearing a sterically hindered meso-phenyl ring with an ethynyl functional group at the para-position was compared to that of its freely rotating counterpart with no methyl substituents on the BODIPY core, with the fluorescence properties in particular proving to be markedly different. These phenyl-ethynyl-substituted BODIPYs were used as the starting materials for the synthesis of novel BODIPY dyes for sensor applications via Sonogashira coupling reactions at the ethynyl position, but this resulted instead in the serendipitous synthesis of a novel BODIPY dimer in which the para-positions of the meso-phenyl rings are linked by a diethynyl bridge. Following iodination at the 2, 6-positions, the dimer was found to have a singlet oxygen quantum yield of 0.88, compared to the value of 0.86 that was obtained for the analogous monomer. Since the εmax values for the main spectral bands of the dimers are significantly higher, the compounds may be of interest for singlet oxygen generation applications. A second study was carried out on the interaction between methyl ester functionalized BODIPY dyes and upconversion nanoparticles (UCNPs) to explore the possible use of BODIPY-UCNP conjugates in biomedical applications. The singlet oxygen generation properties of the BODIPY were tested following iodination at the 2, 6-positions, a singlet oxygen quantum yield value of 0.86 was obtained. Three sets of oleate capped UCNPs were synthesized with different diameters and were rendered water dispersible with the addition of a silica shell. The necessary scaffolding for conjugation to the BODIPY was provided by amine groups following functionalization of this shell. All of the sets of oleate capped and silica coated UCNPs were characterized by transmission electron microscopy (TEM) and X-ray diffractometry (XRD) and their emission properties were studied upon excitation at 978 nm with a diode laser with a Picoquant Fluotime 300 spectrophotometer that enables the measurement of anti-Stokes emission. The potential utility of UCNP-BODIPY conjugates for singlet oxygen applications, such as PDT, was then assessed.
- Full Text:
- Date Issued: 2016
- Authors: Wildervanck, Martijn Johannes
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3718 , vital:20538
- Description: This research explores the use of the versatile 4,4-difluoro-4-boro-3a,4a-diaza-s-indacene (BODIPY) dyes and the modification of their spectroscopic properties. The synthesis of a tetramethyl-BODIPY bearing a sterically hindered meso-phenyl ring with an ethynyl functional group at the para-position was compared to that of its freely rotating counterpart with no methyl substituents on the BODIPY core, with the fluorescence properties in particular proving to be markedly different. These phenyl-ethynyl-substituted BODIPYs were used as the starting materials for the synthesis of novel BODIPY dyes for sensor applications via Sonogashira coupling reactions at the ethynyl position, but this resulted instead in the serendipitous synthesis of a novel BODIPY dimer in which the para-positions of the meso-phenyl rings are linked by a diethynyl bridge. Following iodination at the 2, 6-positions, the dimer was found to have a singlet oxygen quantum yield of 0.88, compared to the value of 0.86 that was obtained for the analogous monomer. Since the εmax values for the main spectral bands of the dimers are significantly higher, the compounds may be of interest for singlet oxygen generation applications. A second study was carried out on the interaction between methyl ester functionalized BODIPY dyes and upconversion nanoparticles (UCNPs) to explore the possible use of BODIPY-UCNP conjugates in biomedical applications. The singlet oxygen generation properties of the BODIPY were tested following iodination at the 2, 6-positions, a singlet oxygen quantum yield value of 0.86 was obtained. Three sets of oleate capped UCNPs were synthesized with different diameters and were rendered water dispersible with the addition of a silica shell. The necessary scaffolding for conjugation to the BODIPY was provided by amine groups following functionalization of this shell. All of the sets of oleate capped and silica coated UCNPs were characterized by transmission electron microscopy (TEM) and X-ray diffractometry (XRD) and their emission properties were studied upon excitation at 978 nm with a diode laser with a Picoquant Fluotime 300 spectrophotometer that enables the measurement of anti-Stokes emission. The potential utility of UCNP-BODIPY conjugates for singlet oxygen applications, such as PDT, was then assessed.
- Full Text:
- Date Issued: 2016
The characterization of and formulation development using a novel tyre devulcanizate
- von Berg, Stuart, Hlangothi, Percy
- Authors: von Berg, Stuart , Hlangothi, Percy
- Date: 2016
- Subjects: Rubber, Reclaimed Rubber chemicals Tires -- Recycling
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/13149 , vital:27156
- Description: The amount of waste tyres being dumped is fast becoming a problem. These stockpiles take up valuable land and are an environmental and health problem. While incineration is the simplest way to recycle the used tyres it isn’t an efficient way to dispose of tyres. This research looks at developing a method for characterizing the New Reclamation Group (NRG) reclaim with the main focus on Hi-Res™ thermogravimetric analysis. Good quantification was possible using this technique. A trade off was established between resolution, sensitivity and time. While increasing the resolution allowed greater separation to be achieved the time for each experiment increased rapidly. Although kinetic models do exist for quantifying rubber components in vulcanized sample, they were not suitable for this study. When devulcanization causes significant molecular changes, such as with NRG reclaim, the decomposition profiles no longer match those of virgin materials. Formulations developed focused on mixing, rheometry, crosslink density and tensile properties. The NRG reclaim acted as a processing aid which lowered the maximum torque. This provides mixing safety as the temperature is decreased as a result of the lower torque. This effect was not seen with conventional reclaim. Rheometry tests indicated that the addition of the devulcanizates decreased the extent of cure. It was demonstrated that this could be linked to crosslink density. Testing of the 100%, 200%, 300% moduli correlated the crosslink density to the maximum torque. Although the addition of NRG reclaim reduced the tensile strength of the formulation, a link between crosslink density and ultimate tensile strength (UTS) couldn’t be made. The decrease in the UTS and increase in extension at break is possibly caused by an increase in low molecular weight material present in the formulations and decrease in crosslink density. This could possibly increase the mobility of polymer chains which could increases flexibility.
- Full Text:
- Date Issued: 2016
- Authors: von Berg, Stuart , Hlangothi, Percy
- Date: 2016
- Subjects: Rubber, Reclaimed Rubber chemicals Tires -- Recycling
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/13149 , vital:27156
- Description: The amount of waste tyres being dumped is fast becoming a problem. These stockpiles take up valuable land and are an environmental and health problem. While incineration is the simplest way to recycle the used tyres it isn’t an efficient way to dispose of tyres. This research looks at developing a method for characterizing the New Reclamation Group (NRG) reclaim with the main focus on Hi-Res™ thermogravimetric analysis. Good quantification was possible using this technique. A trade off was established between resolution, sensitivity and time. While increasing the resolution allowed greater separation to be achieved the time for each experiment increased rapidly. Although kinetic models do exist for quantifying rubber components in vulcanized sample, they were not suitable for this study. When devulcanization causes significant molecular changes, such as with NRG reclaim, the decomposition profiles no longer match those of virgin materials. Formulations developed focused on mixing, rheometry, crosslink density and tensile properties. The NRG reclaim acted as a processing aid which lowered the maximum torque. This provides mixing safety as the temperature is decreased as a result of the lower torque. This effect was not seen with conventional reclaim. Rheometry tests indicated that the addition of the devulcanizates decreased the extent of cure. It was demonstrated that this could be linked to crosslink density. Testing of the 100%, 200%, 300% moduli correlated the crosslink density to the maximum torque. Although the addition of NRG reclaim reduced the tensile strength of the formulation, a link between crosslink density and ultimate tensile strength (UTS) couldn’t be made. The decrease in the UTS and increase in extension at break is possibly caused by an increase in low molecular weight material present in the formulations and decrease in crosslink density. This could possibly increase the mobility of polymer chains which could increases flexibility.
- Full Text:
- Date Issued: 2016
The development of captopril pellets using the principles of quality by design
- Veerubhotla, Hari Mani Krishna
- Authors: Veerubhotla, Hari Mani Krishna
- Date: 2016
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/64769 , vital:28599
- Description: Expected release date-May 2018
- Full Text:
- Date Issued: 2016
- Authors: Veerubhotla, Hari Mani Krishna
- Date: 2016
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/64769 , vital:28599
- Description: Expected release date-May 2018
- Full Text:
- Date Issued: 2016
A longitudinal study of DNS traffic: understanding current DNS practice and abuse
- Authors: Van Zyl, Ignus
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3707 , vital:20537
- Description: This thesis examines a dataset spanning 21 months, containing 3,5 billion DNS packets. Traffic on TCP and UDP port 53, was captured on a production /24 IP block. The purpose of this thesis is twofold. The first is to create an understanding of current practice and behavior within the DNS infrastructure, the second to explore current threats faced by the DNS and the various systems that implement it. This is achieved by drawing on analysis and observations from the captured data. Aspects of the operation of DNS on the greater Internet are considered in this research with reference to the observed trends in the dataset, A thorough analysis of current DNS TTL implementation is made with respect to all response traffic, as well as sections looking at observed DNS TTL values for ,za domain replies and NX DOMAIN flagged replies. This thesis found that TTL values implemented are much lower than has been recommended in previous years, and that the TTL decrease is prevalent in most, but not all EE TTL implementation. With respect to the nature of DNS operations, this thesis also concerns itself with an analysis of the geoloeation of authoritative servers for local (,za) domains, and offers further observations towards the latency generated by the choice of authoritative server location for a given ,za domain. It was found that the majority of ,za domain authoritative servers are international, which results in latency generation that is multiple times greater than observed latencies for local authoritative servers. Further analysis is done with respect to NX DOM AIN behavior captured across the dataset. These findings outlined the cost of DNS miseonfiguration as well as highlighting instances of NXDOMAIN generation through malicious practice. With respect to DNS abuses, original research with respect to long-term scanning generated as a result of amplification attack activity on the greater Internet is presented. Many instances of amplification domain scans were captured during the packet capture, and an attempt is made to correlate that activity temporally with known amplification attack reports. The final area that this thesis deals with is the relatively new field of Bitflipping and Bitsquatting, delivering results on bitflip detection and evaluation over the course of the entire dataset. The detection methodology is outlined, and the final results are compared to findings given in recent bitflip literature.
- Full Text:
- Date Issued: 2016
- Authors: Van Zyl, Ignus
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3707 , vital:20537
- Description: This thesis examines a dataset spanning 21 months, containing 3,5 billion DNS packets. Traffic on TCP and UDP port 53, was captured on a production /24 IP block. The purpose of this thesis is twofold. The first is to create an understanding of current practice and behavior within the DNS infrastructure, the second to explore current threats faced by the DNS and the various systems that implement it. This is achieved by drawing on analysis and observations from the captured data. Aspects of the operation of DNS on the greater Internet are considered in this research with reference to the observed trends in the dataset, A thorough analysis of current DNS TTL implementation is made with respect to all response traffic, as well as sections looking at observed DNS TTL values for ,za domain replies and NX DOMAIN flagged replies. This thesis found that TTL values implemented are much lower than has been recommended in previous years, and that the TTL decrease is prevalent in most, but not all EE TTL implementation. With respect to the nature of DNS operations, this thesis also concerns itself with an analysis of the geoloeation of authoritative servers for local (,za) domains, and offers further observations towards the latency generated by the choice of authoritative server location for a given ,za domain. It was found that the majority of ,za domain authoritative servers are international, which results in latency generation that is multiple times greater than observed latencies for local authoritative servers. Further analysis is done with respect to NX DOM AIN behavior captured across the dataset. These findings outlined the cost of DNS miseonfiguration as well as highlighting instances of NXDOMAIN generation through malicious practice. With respect to DNS abuses, original research with respect to long-term scanning generated as a result of amplification attack activity on the greater Internet is presented. Many instances of amplification domain scans were captured during the packet capture, and an attempt is made to correlate that activity temporally with known amplification attack reports. The final area that this thesis deals with is the relatively new field of Bitflipping and Bitsquatting, delivering results on bitflip detection and evaluation over the course of the entire dataset. The detection methodology is outlined, and the final results are compared to findings given in recent bitflip literature.
- Full Text:
- Date Issued: 2016
Using data mining techniques for the prediction of student dropouts from university science programs
- Authors: Vambe, William Tichaona
- Date: 2016
- Subjects: Data mining Dropout behavior, Prediction of
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12314 , vital:39252
- Description: Data Mining has taken a center stage in education for addressing student dropout challenges as it has become one of the major threat affecting Higher Educational Institutes (HEIs). Being able to predict students who are likely to dropout helps the university to assist those facing challenges early. This will results in producing more graduates with the intellectual capital who will provide skills in the industries, hence addressing the major challenge of skill shortage being faced in South Africa. Studies and researches as purported in literature have been done to address this major threat of dropout challenge by using the theoretical approach which banked on Tinto’s model, followed by the traditional and statistical approach. However, the two lacked accuracy and the automation aspect which makes them difficult and time-consuming to use as they require to be tested periodically for them to be validated. Recently data mining has become a vital tool for predicting non-linear phenomenon including where there is missing data and bringing about accuracy and automation aspect. Data mining usefulness and reliability assessment in education made it possible to be used for prediction by different researchers. As such this research used data mining approach that integrates classification and prediction techniques to analyze student academic data at the University of Fort Hare to create a model for student dropout using preentry data and university academic performance of each student. Following Knowledge Discovery from Database (KDD) framework, data for the students enrolled in the Bachelor of Science programs between 2003 and 2014 was selected. It went through preprocessing and transformation as to deal with the missing data and noise data. Classification algorithms were then used for student characterization. Decision trees (J48) which are found in Weka software were used to build the model for data mining and prediction. The reason for choosing decision trees was it’s ability to deal with textual, nominal and numeric data as was the case with our input data and because they have good precision.The model was then trained using a train data set, validated and evaluated with another data set. Experimental results demonstrations that data mining is useful in predicting students who have chances to drop out. A critical analysis of correctly classifying instances, the confusion matrix and ROC area shows that the model can correctly classify and predict those who are likely to dropout. The model accuracy was 66percent which is a good percentage as supported in literature which means the results produced can be reliably used for assessment and make strategic decisions. Furthermore, the model took a matter of seconds to compute the results when supplied with 400 instances which prove that it is effective and efficient. Grounding our conclusion from these experimental results, this research proved that Data Mining is useful for bringing about automation, accuracy in prediction of student dropouts and the results can be reliably depended on for decision making by faculty managers who are the decision makers.
- Full Text:
- Date Issued: 2016
Using data mining techniques for the prediction of student dropouts from university science programs
- Authors: Vambe, William Tichaona
- Date: 2016
- Subjects: Data mining Dropout behavior, Prediction of
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12314 , vital:39252
- Description: Data Mining has taken a center stage in education for addressing student dropout challenges as it has become one of the major threat affecting Higher Educational Institutes (HEIs). Being able to predict students who are likely to dropout helps the university to assist those facing challenges early. This will results in producing more graduates with the intellectual capital who will provide skills in the industries, hence addressing the major challenge of skill shortage being faced in South Africa. Studies and researches as purported in literature have been done to address this major threat of dropout challenge by using the theoretical approach which banked on Tinto’s model, followed by the traditional and statistical approach. However, the two lacked accuracy and the automation aspect which makes them difficult and time-consuming to use as they require to be tested periodically for them to be validated. Recently data mining has become a vital tool for predicting non-linear phenomenon including where there is missing data and bringing about accuracy and automation aspect. Data mining usefulness and reliability assessment in education made it possible to be used for prediction by different researchers. As such this research used data mining approach that integrates classification and prediction techniques to analyze student academic data at the University of Fort Hare to create a model for student dropout using preentry data and university academic performance of each student. Following Knowledge Discovery from Database (KDD) framework, data for the students enrolled in the Bachelor of Science programs between 2003 and 2014 was selected. It went through preprocessing and transformation as to deal with the missing data and noise data. Classification algorithms were then used for student characterization. Decision trees (J48) which are found in Weka software were used to build the model for data mining and prediction. The reason for choosing decision trees was it’s ability to deal with textual, nominal and numeric data as was the case with our input data and because they have good precision.The model was then trained using a train data set, validated and evaluated with another data set. Experimental results demonstrations that data mining is useful in predicting students who have chances to drop out. A critical analysis of correctly classifying instances, the confusion matrix and ROC area shows that the model can correctly classify and predict those who are likely to dropout. The model accuracy was 66percent which is a good percentage as supported in literature which means the results produced can be reliably used for assessment and make strategic decisions. Furthermore, the model took a matter of seconds to compute the results when supplied with 400 instances which prove that it is effective and efficient. Grounding our conclusion from these experimental results, this research proved that Data Mining is useful for bringing about automation, accuracy in prediction of student dropouts and the results can be reliably depended on for decision making by faculty managers who are the decision makers.
- Full Text:
- Date Issued: 2016
Recombinant expression, purification and in vitro interaction analysis of HOP and RhoC
- Vaaltyn, Michaelone Chantelle
- Authors: Vaaltyn, Michaelone Chantelle
- Date: 2016
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/64523 , vital:28555
- Description: Expected release date-May 2019
- Full Text:
- Date Issued: 2016
- Authors: Vaaltyn, Michaelone Chantelle
- Date: 2016
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/64523 , vital:28555
- Description: Expected release date-May 2019
- Full Text:
- Date Issued: 2016
Single station TEC modelling during storm conditions
- Authors: Uwamahoro, Jean Claude
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3812 , vital:20545
- Description: It has been shown in ionospheric research that modelling total electron content (TEC) during storm conditions is a big challenge. In this study, mathematical equations were developed to estimate TEC over Sutherland (32.38oS, 20.81oE), during storm conditions, using the Empirical Orthogonal Function (EOF) analysis, combined with regression analysis. TEC was derived from GPS observations and a geomagnetic storm was defined for Dst ≤ -50 nT. The inputs for the model were chosen based on the factors that influence TEC variation, such as diurnal, seasonal, solar and geomagnetic activity variation, and these were represented by hour of the day, day number of the year, F10.7 and A index respectively. The EOF model was developed using GPS TEC data from 1999 to 2013 and tested on different storms. For the model validation (interpolation), three storms were chosen in 2000 (solar maximum period) and three others in 2006 (solar minimum period), while for extrapolation six storms including three in 2014 and three in 2015 were chosen. Before building the model, TEC values for the selected 2000 and 2006 storms were removed from the dataset used to construct the model in order to make the model validation independent on data. A comparison of the observed and modelled TEC showed that the EOF model works well for storms with non-significant ionospheric TEC response and storms that occurred during periods of low solar activity. High correlation coefficients between the observed and modelled TEC were obtained showing that the model covers most of the information contained in the observed TEC. Furthermore, it has been shown that the EOF model developed for a specific station may be used to estimate TEC over other locations within a latitudinal and longitudinal coverage of 8.7o and 10.6o respectively. This is an important result as it reduces the data dimensionality problem for computational purposes. It may therefore not be necessary for regional storm-time TEC modelling to compute TEC data for all the closest GPS receiver stations since most of the needed information can be extracted from measurements at one location.
- Full Text:
- Date Issued: 2016
- Authors: Uwamahoro, Jean Claude
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3812 , vital:20545
- Description: It has been shown in ionospheric research that modelling total electron content (TEC) during storm conditions is a big challenge. In this study, mathematical equations were developed to estimate TEC over Sutherland (32.38oS, 20.81oE), during storm conditions, using the Empirical Orthogonal Function (EOF) analysis, combined with regression analysis. TEC was derived from GPS observations and a geomagnetic storm was defined for Dst ≤ -50 nT. The inputs for the model were chosen based on the factors that influence TEC variation, such as diurnal, seasonal, solar and geomagnetic activity variation, and these were represented by hour of the day, day number of the year, F10.7 and A index respectively. The EOF model was developed using GPS TEC data from 1999 to 2013 and tested on different storms. For the model validation (interpolation), three storms were chosen in 2000 (solar maximum period) and three others in 2006 (solar minimum period), while for extrapolation six storms including three in 2014 and three in 2015 were chosen. Before building the model, TEC values for the selected 2000 and 2006 storms were removed from the dataset used to construct the model in order to make the model validation independent on data. A comparison of the observed and modelled TEC showed that the EOF model works well for storms with non-significant ionospheric TEC response and storms that occurred during periods of low solar activity. High correlation coefficients between the observed and modelled TEC were obtained showing that the model covers most of the information contained in the observed TEC. Furthermore, it has been shown that the EOF model developed for a specific station may be used to estimate TEC over other locations within a latitudinal and longitudinal coverage of 8.7o and 10.6o respectively. This is an important result as it reduces the data dimensionality problem for computational purposes. It may therefore not be necessary for regional storm-time TEC modelling to compute TEC data for all the closest GPS receiver stations since most of the needed information can be extracted from measurements at one location.
- Full Text:
- Date Issued: 2016
Effect of phosphorus application on dry matter yield and nutrient content of Mucuna Pruriens (L) in Alice
- Authors: Tshwati, Nolubabalo
- Date: 2016
- Subjects: Legumes Phosphorus Fertilizers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12326 , vital:39253
- Description: The use of herbaceous legumes such as Mucuna (Mucuna pruriens) can assist to recapitalize soil fertility depletion and improve livestock productivity in the small holder farming sector of South Africa. The objective of the study was to investigate the effect of phosphorus fertilizer application (0, 20, 40 and 60 kg P/ha) on the dry matter yield and nutritive value of Mucuna pruriens. The study was conducted at University of Fort Hare Research farm in Alice, South Africa. The research design was a randomized complete block design with three replicates per treatment. Data collection included biomass production and nutrient content of Mucuna pruriens. The forage legume was harvested at flowering stage of growth and analysed for chemical composition. The results showed that with the application of 60 kg P/ha Mucuna had the highest (P < 0.05) fresh and dry matter yield of 19.58 kg/ha and 5.41 kg/ha, respectively compared to other treatments. However, all the other treatments differed from one another. Similarly, the fresh stem and leaf fractions yield and their dry matter yields showed the same trend with application of 60 kg P/ha having the greatest yield compared to the other treatments. Nevertheless, all the treatments differed (P<0.05) from one another with P0 having the least yields. The leaf to stem ratio did not show any significant (P>0.05) difference among all the treatments ranging from 1.44 to 1.62 in fresh forage and ranging from 1.31 to 1.50 in the dry forage. In terms of dry matter content, the control treatment had the highest dry matter content of 37.78percent, however, all the other treatments did not differ significantly (P < 0.05) from each other. There was no significant effect of P application (P > 0.05) in terms of ash, EE, ADF, CP, Ca, Mg, K, Na, P, Zn, Cu, Mn and Fe of the whole plant forage among the treatments. The application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the NDF (51.16percent) of the whole plant of Mucuna compared to the other treatments which did not differ (p>0.05) among themselves. Within the stem fraction there were no significant (P > 0.05) differences among the treatments for the ash, EE, ADF, NDF, and CP, hemicellulose, Ca, Mg, K, P, Zn, Cu, Mn and Fe contents. However, the application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the Na (0.05percent) content of the Mucuna stem fraction. In the leaf fraction of Mucuna there was no significant (P > 0.05) differences in terms of ash, EE, ADF, NDF, CP, hemicellulose, Ca, K, P, Zn, Cu, Mn and Fe among the treatments. However, the application of 20 kg P/ha fertilizer significantly (P < 0.05) increased the Mg (0.52percent) of the Mucuna leaves compared to the other treatments. Therefore the study has shown that increase in P application (60 kg P/ha) has no major effect in the nutrient content of Mucuna. Furthermore, it is recommended that Mucuna can be grown as a protein supplement, based on the CP content values that were recorded in this study and to provide maintenance requirements for ruminants. It was therefore concluded that phosphorus fertilization particularly 60 kg P/ha is necessary and required for optimum growth of Mucuna pruriens in order to increase forage yield. Based on the nutrient content result it was concluded that there was no effect of P fertilizer application levels on the nutrient content of Mucuna pruriens in Alice.
- Full Text:
- Date Issued: 2016
- Authors: Tshwati, Nolubabalo
- Date: 2016
- Subjects: Legumes Phosphorus Fertilizers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12326 , vital:39253
- Description: The use of herbaceous legumes such as Mucuna (Mucuna pruriens) can assist to recapitalize soil fertility depletion and improve livestock productivity in the small holder farming sector of South Africa. The objective of the study was to investigate the effect of phosphorus fertilizer application (0, 20, 40 and 60 kg P/ha) on the dry matter yield and nutritive value of Mucuna pruriens. The study was conducted at University of Fort Hare Research farm in Alice, South Africa. The research design was a randomized complete block design with three replicates per treatment. Data collection included biomass production and nutrient content of Mucuna pruriens. The forage legume was harvested at flowering stage of growth and analysed for chemical composition. The results showed that with the application of 60 kg P/ha Mucuna had the highest (P < 0.05) fresh and dry matter yield of 19.58 kg/ha and 5.41 kg/ha, respectively compared to other treatments. However, all the other treatments differed from one another. Similarly, the fresh stem and leaf fractions yield and their dry matter yields showed the same trend with application of 60 kg P/ha having the greatest yield compared to the other treatments. Nevertheless, all the treatments differed (P<0.05) from one another with P0 having the least yields. The leaf to stem ratio did not show any significant (P>0.05) difference among all the treatments ranging from 1.44 to 1.62 in fresh forage and ranging from 1.31 to 1.50 in the dry forage. In terms of dry matter content, the control treatment had the highest dry matter content of 37.78percent, however, all the other treatments did not differ significantly (P < 0.05) from each other. There was no significant effect of P application (P > 0.05) in terms of ash, EE, ADF, CP, Ca, Mg, K, Na, P, Zn, Cu, Mn and Fe of the whole plant forage among the treatments. The application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the NDF (51.16percent) of the whole plant of Mucuna compared to the other treatments which did not differ (p>0.05) among themselves. Within the stem fraction there were no significant (P > 0.05) differences among the treatments for the ash, EE, ADF, NDF, and CP, hemicellulose, Ca, Mg, K, P, Zn, Cu, Mn and Fe contents. However, the application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the Na (0.05percent) content of the Mucuna stem fraction. In the leaf fraction of Mucuna there was no significant (P > 0.05) differences in terms of ash, EE, ADF, NDF, CP, hemicellulose, Ca, K, P, Zn, Cu, Mn and Fe among the treatments. However, the application of 20 kg P/ha fertilizer significantly (P < 0.05) increased the Mg (0.52percent) of the Mucuna leaves compared to the other treatments. Therefore the study has shown that increase in P application (60 kg P/ha) has no major effect in the nutrient content of Mucuna. Furthermore, it is recommended that Mucuna can be grown as a protein supplement, based on the CP content values that were recorded in this study and to provide maintenance requirements for ruminants. It was therefore concluded that phosphorus fertilization particularly 60 kg P/ha is necessary and required for optimum growth of Mucuna pruriens in order to increase forage yield. Based on the nutrient content result it was concluded that there was no effect of P fertilizer application levels on the nutrient content of Mucuna pruriens in Alice.
- Full Text:
- Date Issued: 2016
The contribution of smallholder agriculture production to food security in rural Zimbabwe : a case study of Masvingo Province
- Authors: Toringepi, Godfrey
- Date: 2016
- Subjects: Farms, Small -- Zimbabwe Agricultural productivity -- Zimbabwe Sustainable agriculture -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5598 , vital:29350
- Description: Agricultural development is back on the development agenda. Even though the smallholder farmers are in the majority and at the forefront in terms of food production and agriculture being the backbone of the economy of Zimbabwe, there is no clearly defined policy on smallholder agriculture in Zimbabwe. The food insecurity has remained a continuous challenge for the rural poor in Zimbabwe. This study investigated the contribution of smallholder agriculture to food security with particular reference to the Masvingo province. The study employed qualitative method of research entailing extensive review of literature as a method of data collection. The study utilized the modernisation theory and sustainable livelihoods framework to illustrate smallholder agriculture and food security nexus. The study revealed that smallholder agriculture is the best option for addressing food security since agriculture is considered the main livelihood strategy for small scale farmers in Zimbabwe. There is general scholarly consensus that the main cause of food insecurity in Zimbabwe is a decrease in smallholder agriculture productivity. The study revealed that poor infrastructure , limited access to credit, limited access to inputs, poor investment in human development, limited access to markets and harsh climatic conditions weaken the capacity of small scale farmers to improve food security. Key recommendations are that supportive institutions need to be put in place to strengthen the smallholder farmer’s capacity to improve food security in Zimbabwe.
- Full Text:
- Date Issued: 2016
- Authors: Toringepi, Godfrey
- Date: 2016
- Subjects: Farms, Small -- Zimbabwe Agricultural productivity -- Zimbabwe Sustainable agriculture -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5598 , vital:29350
- Description: Agricultural development is back on the development agenda. Even though the smallholder farmers are in the majority and at the forefront in terms of food production and agriculture being the backbone of the economy of Zimbabwe, there is no clearly defined policy on smallholder agriculture in Zimbabwe. The food insecurity has remained a continuous challenge for the rural poor in Zimbabwe. This study investigated the contribution of smallholder agriculture to food security with particular reference to the Masvingo province. The study employed qualitative method of research entailing extensive review of literature as a method of data collection. The study utilized the modernisation theory and sustainable livelihoods framework to illustrate smallholder agriculture and food security nexus. The study revealed that smallholder agriculture is the best option for addressing food security since agriculture is considered the main livelihood strategy for small scale farmers in Zimbabwe. There is general scholarly consensus that the main cause of food insecurity in Zimbabwe is a decrease in smallholder agriculture productivity. The study revealed that poor infrastructure , limited access to credit, limited access to inputs, poor investment in human development, limited access to markets and harsh climatic conditions weaken the capacity of small scale farmers to improve food security. Key recommendations are that supportive institutions need to be put in place to strengthen the smallholder farmer’s capacity to improve food security in Zimbabwe.
- Full Text:
- Date Issued: 2016
Evaluating farmers' perceptions and the impact of bush encroachment on herbaceous vegetation and soil nutrients in Sheshegu communal rangelands of the Eastern Cape, South Africa
- Authors: Tokozwayo, Sive
- Date: 2016
- Subjects: Range management -- South Africa -- Eastern Cape Brush -- Control -- South Africa -- Eastern Cape Communal rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2733 , vital:28066
- Description: Communal rangelands occupy 13 percent of the agricultural land in South Africa, and these rangelands serve as a source of feed to livestock. These areas are threatened by bush encroachment due to poor rangeland management. This study was conducted in Alice (Sheshegu communal area) and the objective was to assess farmers' perceptions and the impact of bush encroachment on herbaceous vegetation and soil nutrients. Structured questionnaires were used to assess indigenous knowledge of communal farmers on the impact of bush encroachment on rangelands. Fourty (40) respondents from households who owned livestock were randomly selected and interviewed at Sheshegu village. About 89 percent of communal farmers perceived that change of their grasslands to encroached savannas was caused by unreliable rainfall, prolonged drought, and poor rangeland management. Rangeland assessment was performed at four sites (Scattered, Moderate, Mixed and Dense bushland. 100mx50m were demarcated per site, and four 100m transects were laid parallel to each other, 30m apart. The step point method was used to determine both species composition and basal cover. Biomass production was determined by harvesting forage within randomly-paced a 0.25m2 quadrats. Aristada congesta and Eragrostis obtuse were the most dominating grass species in dense, mixed and moderate bushland. Scattered bushland was dominated by Themeda triandra. Biomass production increases with increase in bush density and basal cover improved from winter to summer season. Increaser grass species increase with the increase in bush density, this indicated that the rangeland was poorly managed and palatable species were being replaced by less palatable ones. Species composition of woody plants was determined within a 200m2 belt transect in all sites. Maytenus polycantha, Aloe ferox, Erehia rigida and lucas capensis were the most dominant woody species in Mixed bushland while Acacia karroo was most dominated in Scattered, Moderate and Dense bushland. Woody density showed no significant differences (P> 0.05) between Dense, Mixed and Moderate bushland. Woody plant density in all these sites exceed 2500 plants/ha, which showed that the rangeland was encroached with woody plants. Soil nutrient content was determined for each site. Five samples of soil were collected per site to test the effect of bush encroachment on soil nutrient composition. The concentration of nitrogen and soil pH increased with increase in bush density, while that of potassium, phosphorous, magnesium, sodium and sulphur showed no significant differences (P>0.05) across all homogenous vegetation units. The study revealed that Sheshegu communal farmers are aware of both negative and positive effects of encroachment on their community, and also argue that the government is not willing to support communal farmers in the process of reducing the spread of bush encroachment. It was concluded that the concentration of nitrogen and soil pH increased with increasing bush density and that bush encroachment had negative effects on herbaceous species. It was recommended that communal farmers should be formulating rangeland rules and regulations to manage rangeland resources. Rangeland rules and regulations should be based on the management of livestock management during grazing and harvesting of rangeland resources. The harvesting of woody and good timing of application of fire can also reduce the spread of bush encroachment. Veld resting and rotational grazing can also improve fuel load which is required for burning of woody plants. Furthermore, Department of agriculture should also provide workshops or training to communal farmers use different approaches or cheap ways of reducing bush encroachment and conserving rangeland resources.
- Full Text:
- Date Issued: 2016
- Authors: Tokozwayo, Sive
- Date: 2016
- Subjects: Range management -- South Africa -- Eastern Cape Brush -- Control -- South Africa -- Eastern Cape Communal rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2733 , vital:28066
- Description: Communal rangelands occupy 13 percent of the agricultural land in South Africa, and these rangelands serve as a source of feed to livestock. These areas are threatened by bush encroachment due to poor rangeland management. This study was conducted in Alice (Sheshegu communal area) and the objective was to assess farmers' perceptions and the impact of bush encroachment on herbaceous vegetation and soil nutrients. Structured questionnaires were used to assess indigenous knowledge of communal farmers on the impact of bush encroachment on rangelands. Fourty (40) respondents from households who owned livestock were randomly selected and interviewed at Sheshegu village. About 89 percent of communal farmers perceived that change of their grasslands to encroached savannas was caused by unreliable rainfall, prolonged drought, and poor rangeland management. Rangeland assessment was performed at four sites (Scattered, Moderate, Mixed and Dense bushland. 100mx50m were demarcated per site, and four 100m transects were laid parallel to each other, 30m apart. The step point method was used to determine both species composition and basal cover. Biomass production was determined by harvesting forage within randomly-paced a 0.25m2 quadrats. Aristada congesta and Eragrostis obtuse were the most dominating grass species in dense, mixed and moderate bushland. Scattered bushland was dominated by Themeda triandra. Biomass production increases with increase in bush density and basal cover improved from winter to summer season. Increaser grass species increase with the increase in bush density, this indicated that the rangeland was poorly managed and palatable species were being replaced by less palatable ones. Species composition of woody plants was determined within a 200m2 belt transect in all sites. Maytenus polycantha, Aloe ferox, Erehia rigida and lucas capensis were the most dominant woody species in Mixed bushland while Acacia karroo was most dominated in Scattered, Moderate and Dense bushland. Woody density showed no significant differences (P> 0.05) between Dense, Mixed and Moderate bushland. Woody plant density in all these sites exceed 2500 plants/ha, which showed that the rangeland was encroached with woody plants. Soil nutrient content was determined for each site. Five samples of soil were collected per site to test the effect of bush encroachment on soil nutrient composition. The concentration of nitrogen and soil pH increased with increase in bush density, while that of potassium, phosphorous, magnesium, sodium and sulphur showed no significant differences (P>0.05) across all homogenous vegetation units. The study revealed that Sheshegu communal farmers are aware of both negative and positive effects of encroachment on their community, and also argue that the government is not willing to support communal farmers in the process of reducing the spread of bush encroachment. It was concluded that the concentration of nitrogen and soil pH increased with increasing bush density and that bush encroachment had negative effects on herbaceous species. It was recommended that communal farmers should be formulating rangeland rules and regulations to manage rangeland resources. Rangeland rules and regulations should be based on the management of livestock management during grazing and harvesting of rangeland resources. The harvesting of woody and good timing of application of fire can also reduce the spread of bush encroachment. Veld resting and rotational grazing can also improve fuel load which is required for burning of woody plants. Furthermore, Department of agriculture should also provide workshops or training to communal farmers use different approaches or cheap ways of reducing bush encroachment and conserving rangeland resources.
- Full Text:
- Date Issued: 2016
Do differences in personality traits affect how drivers experience music at different intensities?
- Authors: Tlhoaele, Kebaabetswe
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3695 , vital:20536
- Description: Various researchers have investigated contributing factors towards the number of acute traffic incidences in and around Southern Africa. Some of these contributing factors include: the skills component of the driver predominately attributed to driving experience as well as the behavioural component influenced by the driver’s natural predisposition, individual differences and personality traits. In order to manage these factors drivers have developed varying coping mechanisms. One of these coping mechanisms is listening to music while driving, which is readily available in most cars and extensively used predominately during long duration driving. Listening to music neither increases one’s driving duration (as opposed to taking several breaks), nor does it interfere with the physical movements of driving (in the manner that eating and drinking may), but it might impact the concentration and attention of some drivers. This is based on the notion that music is assumed to impact arousal and cognitive ability. While there are several studies on the effect of music on driving performance and personality traits very few studies have looked at whether music has a positive or negative effect on driving performance based on differences in personality traits; and whether the extent of this effect might differ for different intensities of music? Consequently, this study aims to understand and determine the extent to which different personality traits predict the effect that listening to different music intensities has on driving performance. The impact of differing music conditions on the different personality traits used a repeated measures design and a between group design with respect to the personality traits with a sample size of (n=25)-16 females and 9 males-and their ages ranged between 19-35 years of age. The average age and standard deviation for this sample size was 22 years±2. A low-fidelity driving simulator task was utilised in order to provide a controllable, repeatable and a safe environment as compared to a real road situation. Personality was assessed using an online Big-Five Inventory scale (extraversion, agreeableness, conscientiousness, neuroticism, openness). All the different personality groups completed three conditions (45 minutes each) in a randomised order (without music, moderately loud music and loud music). Psychophysiological parameters i.e. heart rate frequency (HRF), heart rate variability (HRV) and eye movements (pupil diameter, eye speeds, fixation duration, blink frequency and blink duration) and driving performance were measured continuously. Subjective performance Multidimensional Driving Style Inventory was measured once-off prior to completion of the testing sessions, whilst the NASA-Task Load Index scale and Perceived control of participants were assessed after each condition. The expected outcomes revealed that music had an effect on objective driving performance (tracking deviation and reaction time) and psychophysiological measures only for participants of certain personality types while other personality types were unaffected by music. The subjective performance measures did not follow the same trend as objective performance measures. The conditions did not reveal an effect on driving performance, for most of the psychophysiological parameters and subjective measures. There was mainly a significant time on task effect and interactional effects on the psychophysiological measures (physiological and oculomotor) parameters at (p<0.05), but not on the subjective measures as anticipated. The study illustrated that the there are differences between personality traits. There was difficulty in the interpretation of the results based on the complexity of the findings for which each hypothesis was partially accepted. The research may establish practical implications for traffic safety campaigns in South Africa, as well as influence driving education for citizens. Assessing the personality trait would help to form an understanding as to which of the personality traits might be affected negatively from listening to music while driving and those that might benefit. Moreover, this study may assist motorists in understanding the implications of listening to music while driving as this may sometimes elicit risky driving behaviour and possibly cause an accident that may result in death.
- Full Text:
- Date Issued: 2016
- Authors: Tlhoaele, Kebaabetswe
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3695 , vital:20536
- Description: Various researchers have investigated contributing factors towards the number of acute traffic incidences in and around Southern Africa. Some of these contributing factors include: the skills component of the driver predominately attributed to driving experience as well as the behavioural component influenced by the driver’s natural predisposition, individual differences and personality traits. In order to manage these factors drivers have developed varying coping mechanisms. One of these coping mechanisms is listening to music while driving, which is readily available in most cars and extensively used predominately during long duration driving. Listening to music neither increases one’s driving duration (as opposed to taking several breaks), nor does it interfere with the physical movements of driving (in the manner that eating and drinking may), but it might impact the concentration and attention of some drivers. This is based on the notion that music is assumed to impact arousal and cognitive ability. While there are several studies on the effect of music on driving performance and personality traits very few studies have looked at whether music has a positive or negative effect on driving performance based on differences in personality traits; and whether the extent of this effect might differ for different intensities of music? Consequently, this study aims to understand and determine the extent to which different personality traits predict the effect that listening to different music intensities has on driving performance. The impact of differing music conditions on the different personality traits used a repeated measures design and a between group design with respect to the personality traits with a sample size of (n=25)-16 females and 9 males-and their ages ranged between 19-35 years of age. The average age and standard deviation for this sample size was 22 years±2. A low-fidelity driving simulator task was utilised in order to provide a controllable, repeatable and a safe environment as compared to a real road situation. Personality was assessed using an online Big-Five Inventory scale (extraversion, agreeableness, conscientiousness, neuroticism, openness). All the different personality groups completed three conditions (45 minutes each) in a randomised order (without music, moderately loud music and loud music). Psychophysiological parameters i.e. heart rate frequency (HRF), heart rate variability (HRV) and eye movements (pupil diameter, eye speeds, fixation duration, blink frequency and blink duration) and driving performance were measured continuously. Subjective performance Multidimensional Driving Style Inventory was measured once-off prior to completion of the testing sessions, whilst the NASA-Task Load Index scale and Perceived control of participants were assessed after each condition. The expected outcomes revealed that music had an effect on objective driving performance (tracking deviation and reaction time) and psychophysiological measures only for participants of certain personality types while other personality types were unaffected by music. The subjective performance measures did not follow the same trend as objective performance measures. The conditions did not reveal an effect on driving performance, for most of the psychophysiological parameters and subjective measures. There was mainly a significant time on task effect and interactional effects on the psychophysiological measures (physiological and oculomotor) parameters at (p<0.05), but not on the subjective measures as anticipated. The study illustrated that the there are differences between personality traits. There was difficulty in the interpretation of the results based on the complexity of the findings for which each hypothesis was partially accepted. The research may establish practical implications for traffic safety campaigns in South Africa, as well as influence driving education for citizens. Assessing the personality trait would help to form an understanding as to which of the personality traits might be affected negatively from listening to music while driving and those that might benefit. Moreover, this study may assist motorists in understanding the implications of listening to music while driving as this may sometimes elicit risky driving behaviour and possibly cause an accident that may result in death.
- Full Text:
- Date Issued: 2016
The biomass production, nutrient content and silage quality of Perennial ryegrass (Lolium perenne (L)) Cocksfoot (Dactylis glomerata (L)) and Tall fescue (Festuca arundinacea (Schreb)) varieties grown under irrigation in Alice, South Africa
- Authors: Tikwayo, Sizwe Edward
- Date: 2016
- Subjects: Ryegrasses -- Varieties -- South Africa -- Eastern Cape Ryegrasses -- Irrigation -- South Africa -- Eastern Cape Biomass energy -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/1796 , vital:27560
- Description: The study aims to evaluate the biomass production and nutrient content and silage quality of perennial ryegrass (Lolium perenne (L)), cocksfoot (Dactylis glomerata (L)) and tall fescue (Festuca arundinacea (Schreb)). Six varieties were used, two for each species. A completely randomized block designed replicated three times was conducted at University of Fort Hare Research Farm during 2014-2015 growing season. The plots were harvested at four-week interval (post emergency) for one year. Biomass yields were measured for fresh forage and dry matter yield. Duplicated samples were then dried, milled and analyzed for chemical and mineral composition (CP, NDF, ADF, and ash, Ca, P, K, Na, Mn, Cu, Zn and Fe) for only winter season. In addition the grasses were ensiled and the silage was analyzed for its fermentation parameters and nutrient content (lactic acid, pH, DM, CP, NDF, ADF, and ash, Ca, P, K, Na, Mn, Cu, Zn and Fe). Biomass results showed significant differences (P < 0.05) between season and varieties. On average Tall fescue varieties Jessup (13741.67 FM kg/ha), Alix (12007.78 FM kg/ ha) and Ryegrass varieties Samson (11597.22 FM kg/ha) and Nui (10591.67 FM kg/ha) had the highest fresh biomass yield. Similarly, Tall fescue varieties Jessup (2833.06 DM kg/ha) and Alix (2708.3 DM kg/ ha) and Ryegrass varieties Samson (2169.44 DM kg/ha) and Nui (2169.67 kg/ha) had the highest dry biomass yield. Throughout the year the average biomass yield was significantly different among species (P< 0.05). During summer and autumn Tall fescue varieties Jessup and Alix gave the highest dry matter yields of 3855.5 to 1977.8 DM kg/ha, and 3877.8 to 1900 DM kg/ha, respectively, and followed by Cocksfoot 2400 DM kg/ha. Ryegrass had the highest dry matter biomass yield in winter (2975 DM kg/ha) and the least in summer (977.75 DM kg/ha). There were no significant (P>0.05) differences on the chemical composition (CP, NDF, ADF, and ash) and mineral composition (Ca, P, K, Na, Mn, Cu, Zn and Fe) of the six varieties. The grass silage results showed significant differences (P< 0.05) among the six varieties for moisture content. Perennial ryegrass variety Nui (66.76 percent) had low moisture content than the other grass silages. The different varieties had no significant effects (P>0.05) on chemical composition (CP, NDF, ADF, and ash) and mineral composition (Ca, P, K, Na, Mn, Cu, Zn and Fe). It is concluded that the biomass production of the six varieties of three grass species was different throughout the year under irrigation hence Ryegrass and Tall fescue are recommended for dairy farmers in the region for all seasons. It can be concluded that there is no difference with respect to fermentation characteristics and nutrient content among the varieties of the grass species.
- Full Text:
- Date Issued: 2016
- Authors: Tikwayo, Sizwe Edward
- Date: 2016
- Subjects: Ryegrasses -- Varieties -- South Africa -- Eastern Cape Ryegrasses -- Irrigation -- South Africa -- Eastern Cape Biomass energy -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/1796 , vital:27560
- Description: The study aims to evaluate the biomass production and nutrient content and silage quality of perennial ryegrass (Lolium perenne (L)), cocksfoot (Dactylis glomerata (L)) and tall fescue (Festuca arundinacea (Schreb)). Six varieties were used, two for each species. A completely randomized block designed replicated three times was conducted at University of Fort Hare Research Farm during 2014-2015 growing season. The plots were harvested at four-week interval (post emergency) for one year. Biomass yields were measured for fresh forage and dry matter yield. Duplicated samples were then dried, milled and analyzed for chemical and mineral composition (CP, NDF, ADF, and ash, Ca, P, K, Na, Mn, Cu, Zn and Fe) for only winter season. In addition the grasses were ensiled and the silage was analyzed for its fermentation parameters and nutrient content (lactic acid, pH, DM, CP, NDF, ADF, and ash, Ca, P, K, Na, Mn, Cu, Zn and Fe). Biomass results showed significant differences (P < 0.05) between season and varieties. On average Tall fescue varieties Jessup (13741.67 FM kg/ha), Alix (12007.78 FM kg/ ha) and Ryegrass varieties Samson (11597.22 FM kg/ha) and Nui (10591.67 FM kg/ha) had the highest fresh biomass yield. Similarly, Tall fescue varieties Jessup (2833.06 DM kg/ha) and Alix (2708.3 DM kg/ ha) and Ryegrass varieties Samson (2169.44 DM kg/ha) and Nui (2169.67 kg/ha) had the highest dry biomass yield. Throughout the year the average biomass yield was significantly different among species (P< 0.05). During summer and autumn Tall fescue varieties Jessup and Alix gave the highest dry matter yields of 3855.5 to 1977.8 DM kg/ha, and 3877.8 to 1900 DM kg/ha, respectively, and followed by Cocksfoot 2400 DM kg/ha. Ryegrass had the highest dry matter biomass yield in winter (2975 DM kg/ha) and the least in summer (977.75 DM kg/ha). There were no significant (P>0.05) differences on the chemical composition (CP, NDF, ADF, and ash) and mineral composition (Ca, P, K, Na, Mn, Cu, Zn and Fe) of the six varieties. The grass silage results showed significant differences (P< 0.05) among the six varieties for moisture content. Perennial ryegrass variety Nui (66.76 percent) had low moisture content than the other grass silages. The different varieties had no significant effects (P>0.05) on chemical composition (CP, NDF, ADF, and ash) and mineral composition (Ca, P, K, Na, Mn, Cu, Zn and Fe). It is concluded that the biomass production of the six varieties of three grass species was different throughout the year under irrigation hence Ryegrass and Tall fescue are recommended for dairy farmers in the region for all seasons. It can be concluded that there is no difference with respect to fermentation characteristics and nutrient content among the varieties of the grass species.
- Full Text:
- Date Issued: 2016
Reproductive biology of important invasive plants in the Eastern Cape Province of South Africa
- Authors: Thorne, Cara-Jayne
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3683 , vital:20535
- Description: Baker’s rule predicts species capable of uniparental reproduction are more likely to establish after long distance dispersal (or introduction in the case of invasive plants), thus the ability to undergo autonomous self-pollination should promote colonization. An investigation into the reproductive biology of eleven invasive species in the Eastern Cape Province of South Africa between 2012 and 2014 showed strong support for Baker’s law. Breeding system results showed evidence of self-compatibility in eight species, ten species were capable of autonomous self-pollination, and only three species showed evidence of varying levels of self-incompatibility. These results provide evdence that autonomous self-pollination occurs more frequently among invasive species, self-compatible species more frequently become invasive compared with self-incompatible species and that autogamous species should have a larger invasive range. Co-opting suitable local pollinators may be problematic for invasive plants, especially those with highly specialized pollination systems. The species investigated appear to be largely independent of pollinators, mostly setting seed in the absence of pollinators. Despite this, all eleven invasive plant species are regularly visited by a variety of generalist pollinators including Apis mellifera, Xylocopa bees and Allodapini species. Pollinators all carried substantial pollen loads, even managing to extract pollen from more specialized plants, such as the poricidal anthers of Solanum species, and frequently came into contact with both anthers and stigmas. Considering most of theses species are capable of autonomous self-pollination, their reliance on pollinators may be low. Even the most self-incompatible species, Passiflora caerulea, appears to have successfully co-opted local pollinators (honeybees and carpenter bees), ensuring successful pollination and seed set. The ability for cross-pollination by local pollinators allows for some degree of genetic variation within invasive plant populations, especially for self-incompatible species. Inadequate pollen deposition by unreliable or inefficient pollinators, or reduced resource availability, can result in pollen limitation. Invasive plant species may be especially susceptible, with three of the plant species investiagted showing possible pollen limitation at the level of seed set, while the remaining nine invasive plant species showed no evidence of pollen limitation in South Africa. The ability to utilize uniparental reproduction (as Baker’s law predicted), and co-opt local pollinators has allowed invasive plants in the Eastern Cape to successfully establish and persist after introduction. Hence, the inclusion of reproductive traits of plants should therefore be included in risk assessments for future plant invaders.
- Full Text:
- Date Issued: 2016
- Authors: Thorne, Cara-Jayne
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3683 , vital:20535
- Description: Baker’s rule predicts species capable of uniparental reproduction are more likely to establish after long distance dispersal (or introduction in the case of invasive plants), thus the ability to undergo autonomous self-pollination should promote colonization. An investigation into the reproductive biology of eleven invasive species in the Eastern Cape Province of South Africa between 2012 and 2014 showed strong support for Baker’s law. Breeding system results showed evidence of self-compatibility in eight species, ten species were capable of autonomous self-pollination, and only three species showed evidence of varying levels of self-incompatibility. These results provide evdence that autonomous self-pollination occurs more frequently among invasive species, self-compatible species more frequently become invasive compared with self-incompatible species and that autogamous species should have a larger invasive range. Co-opting suitable local pollinators may be problematic for invasive plants, especially those with highly specialized pollination systems. The species investigated appear to be largely independent of pollinators, mostly setting seed in the absence of pollinators. Despite this, all eleven invasive plant species are regularly visited by a variety of generalist pollinators including Apis mellifera, Xylocopa bees and Allodapini species. Pollinators all carried substantial pollen loads, even managing to extract pollen from more specialized plants, such as the poricidal anthers of Solanum species, and frequently came into contact with both anthers and stigmas. Considering most of theses species are capable of autonomous self-pollination, their reliance on pollinators may be low. Even the most self-incompatible species, Passiflora caerulea, appears to have successfully co-opted local pollinators (honeybees and carpenter bees), ensuring successful pollination and seed set. The ability for cross-pollination by local pollinators allows for some degree of genetic variation within invasive plant populations, especially for self-incompatible species. Inadequate pollen deposition by unreliable or inefficient pollinators, or reduced resource availability, can result in pollen limitation. Invasive plant species may be especially susceptible, with three of the plant species investiagted showing possible pollen limitation at the level of seed set, while the remaining nine invasive plant species showed no evidence of pollen limitation in South Africa. The ability to utilize uniparental reproduction (as Baker’s law predicted), and co-opt local pollinators has allowed invasive plants in the Eastern Cape to successfully establish and persist after introduction. Hence, the inclusion of reproductive traits of plants should therefore be included in risk assessments for future plant invaders.
- Full Text:
- Date Issued: 2016
Seasonal variations of essential oil composition and some biological evaluation of Pelargonium inquinans (L.) Ait. South Africa
- Authors: Tembeni, Babalwa
- Date: 2016
- Subjects: Pelargoniums Essences and essential oils Medicinal plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6281 , vital:29537
- Description: Pelargonium inquinans which belongs to the family Geraniaceae, is an essential oil yielding plant. P. inquinans was collected from two different sites in Grahamstown (wild) and Alice, at the University of Fort Hare botanical garden. Authentication of the plant was done by Dr. T. Dold at Schonland herbarium, and the voucher specimen being T01. This study is focused at determining the chemical constituents and biological properties of the essential oils of wild and cultivated P. inquinans across different seasons, as the plant grows throughout the year. Seasonal collection of wild and cultivated P. inquinans was achieved in a duration of 12 months. 32 essential oil samples of P. inquinans were obtained by extraction using hydro-distillation technique for 3-4 hours. The chemical composition of the essential oils was determined using GC/MS and GC/FID. Amongst the 32 essential oils only 4 samples wild ( fresh stem and leaf) and cultivated ( fresh stem and leaf) from summer season were evaluated for analgesic activity using acetic acid induced writhings and hot plate nociception models in mice, anti-inflammatory activity was determined on the egg albumin- induced rat paw oedema in rats. The results obtained from GC-MS revealed a total of 169 components obtained from the leafstem, fresh/dry wild and cultivated P. inquinans. These essential oils showed a great deal of chemotaxonomic variation and similarity in the major and minor components along the season. In spring season the essential oils of wild and cultivated P. inquinans had abundance of hydrogenated sesquiterpenes (20.6percent-66.7percent). The major components were found to be α-caryophyllene (9.1percent-26.8percent), p-xylene (23.3percent-27.5percent), β-caryophyllene (11.4percent-30.9percent), o-xylene (6.3percent-39.4percent), β-thujene (8.7percent), isocaryophyllene (13.9percent), isoborneol (14.2percent), β-myrcene (5.7percent), geranyl acetate (13.8percent), toluene (7.9percent), β-gurjunene (18.5percent), α-cadinene (15.8percent), β-farnesene (14.2percent), 3-carene (12.1percent) and camphene (9.0percent). In summer season the essential oils of wild and cultivated P. inquinans were found to have abundance of hydrogenated sesquiterpenes (50.3percent- 63.0percent), oxygenated monoterpenes (30.4percent) and hydrogenated monoterpenes (20.8percent- 61.0percent). The major components were found to be α-caryophyllene (12.3percent-25.8percent), β-caryophyllene (15.1percent- 31.7percent), trans-caryophyllene (10.3percent- 17.8percent), phytol (14.2percent- 20.2percent), camphor (46.5percent), sabinene (27.8percent), elemol (18.1percent), z3-hexenyl isobutyrate (16.3percent), limonene (12.1percent), menthone (12.1percent)< E.E-β-farnesene (14.7percent), palmitic acid (9.6percent), eugenol (9.4percent), cis- β-ocimene (8.7percent), α-terpineol (8.7percent), geranyl acetone (7.8percent), β- humulene (7.5percent). linoleic acid (7.4percent), trans-linalool oxide (7.4percent), β-bisabolene (7.1percent), cis- linalool oxide (7.1percent), ionone (6.9percent), caryophyllene oxide (6.9percent) and germacrene d (6.3percent). In autumn season the essential oils of wild and cultivated P. inquinans were found to be rich in hydrogenated sesquiterpenes (29.3percent- 65.2percent) and oxygenated sesquiterpenes (22.8percent- 31.4percent). The major components were found to be α-caryophyllene (15.5percent- 23.4percent), β-caryophyllene (15.2percent- 17.2percent), β-myrcene (7.7percent-13.8percent), β-humulene (8.7percent- 15.2percent), caryophyllene oxide (9.8- 16.2percent), trans- caryophyllene (16.7percent- 23.3percent), α-humulene (11.8percent- 18.6percent), linoleic acid (11.2percent), palmitic acid (10.4percent), phytol acetate (8.5percent), -longipinene (8.3percent) and citronellol (7.8percent). In winter season the essential oils of wild and cultivated P. inquinans were found to have abundance of hydrogenated sesquiterpenes (25.1percent- 48.6percent), oxygenated monoterpenes (47.6percent), oxygenated sesquiterpenes (22.2percent- 28.0percent). The major components were found to be β-caryophyllene (14.6percent- 23.0percent), α-caryophyllene (9.4percent- 18.0percent), trans- caryophyllene (12.2percent- 14.6percent), α-cedrene (26.2percent), germacrene –d-4-ol (16.8percent), 2,6-dihydroxyacetophenone (15.6percent), (+) epibicyclosesquiphellandrene (15.3percent), E-β- farnesene (13.0percent), β-phellandrene (11.7percent), 2-nitrophenol (9.5percent), palatinol (8.4percent), geranyl acetate (7.7percent) and linoleic acid (7.4percent). The oils from the wild and cultivated sources showed significant (p<0.05-0.001) decrease in number of writhes induced by the acetic acid compared to vehicle; caused significant (p<0.05-0.001) delay in reaction time on the hot plate at 60 and 90 min post-treatment and significantly (p<0.05-0.001) reduced oedema size caused by the egg albumin injection compared to the vehicle. The oils from the wild plant showed more potency compared to the cultivated. The essential oils of wild and cultivated P. inquinans showed qualitative, quantitative and chemotaxonomic variation with analgesic and anti-inflammatory activity. These essential oils need to be explored for further biological analysis because of the major components they contain.
- Full Text:
- Date Issued: 2016
- Authors: Tembeni, Babalwa
- Date: 2016
- Subjects: Pelargoniums Essences and essential oils Medicinal plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6281 , vital:29537
- Description: Pelargonium inquinans which belongs to the family Geraniaceae, is an essential oil yielding plant. P. inquinans was collected from two different sites in Grahamstown (wild) and Alice, at the University of Fort Hare botanical garden. Authentication of the plant was done by Dr. T. Dold at Schonland herbarium, and the voucher specimen being T01. This study is focused at determining the chemical constituents and biological properties of the essential oils of wild and cultivated P. inquinans across different seasons, as the plant grows throughout the year. Seasonal collection of wild and cultivated P. inquinans was achieved in a duration of 12 months. 32 essential oil samples of P. inquinans were obtained by extraction using hydro-distillation technique for 3-4 hours. The chemical composition of the essential oils was determined using GC/MS and GC/FID. Amongst the 32 essential oils only 4 samples wild ( fresh stem and leaf) and cultivated ( fresh stem and leaf) from summer season were evaluated for analgesic activity using acetic acid induced writhings and hot plate nociception models in mice, anti-inflammatory activity was determined on the egg albumin- induced rat paw oedema in rats. The results obtained from GC-MS revealed a total of 169 components obtained from the leafstem, fresh/dry wild and cultivated P. inquinans. These essential oils showed a great deal of chemotaxonomic variation and similarity in the major and minor components along the season. In spring season the essential oils of wild and cultivated P. inquinans had abundance of hydrogenated sesquiterpenes (20.6percent-66.7percent). The major components were found to be α-caryophyllene (9.1percent-26.8percent), p-xylene (23.3percent-27.5percent), β-caryophyllene (11.4percent-30.9percent), o-xylene (6.3percent-39.4percent), β-thujene (8.7percent), isocaryophyllene (13.9percent), isoborneol (14.2percent), β-myrcene (5.7percent), geranyl acetate (13.8percent), toluene (7.9percent), β-gurjunene (18.5percent), α-cadinene (15.8percent), β-farnesene (14.2percent), 3-carene (12.1percent) and camphene (9.0percent). In summer season the essential oils of wild and cultivated P. inquinans were found to have abundance of hydrogenated sesquiterpenes (50.3percent- 63.0percent), oxygenated monoterpenes (30.4percent) and hydrogenated monoterpenes (20.8percent- 61.0percent). The major components were found to be α-caryophyllene (12.3percent-25.8percent), β-caryophyllene (15.1percent- 31.7percent), trans-caryophyllene (10.3percent- 17.8percent), phytol (14.2percent- 20.2percent), camphor (46.5percent), sabinene (27.8percent), elemol (18.1percent), z3-hexenyl isobutyrate (16.3percent), limonene (12.1percent), menthone (12.1percent)< E.E-β-farnesene (14.7percent), palmitic acid (9.6percent), eugenol (9.4percent), cis- β-ocimene (8.7percent), α-terpineol (8.7percent), geranyl acetone (7.8percent), β- humulene (7.5percent). linoleic acid (7.4percent), trans-linalool oxide (7.4percent), β-bisabolene (7.1percent), cis- linalool oxide (7.1percent), ionone (6.9percent), caryophyllene oxide (6.9percent) and germacrene d (6.3percent). In autumn season the essential oils of wild and cultivated P. inquinans were found to be rich in hydrogenated sesquiterpenes (29.3percent- 65.2percent) and oxygenated sesquiterpenes (22.8percent- 31.4percent). The major components were found to be α-caryophyllene (15.5percent- 23.4percent), β-caryophyllene (15.2percent- 17.2percent), β-myrcene (7.7percent-13.8percent), β-humulene (8.7percent- 15.2percent), caryophyllene oxide (9.8- 16.2percent), trans- caryophyllene (16.7percent- 23.3percent), α-humulene (11.8percent- 18.6percent), linoleic acid (11.2percent), palmitic acid (10.4percent), phytol acetate (8.5percent), -longipinene (8.3percent) and citronellol (7.8percent). In winter season the essential oils of wild and cultivated P. inquinans were found to have abundance of hydrogenated sesquiterpenes (25.1percent- 48.6percent), oxygenated monoterpenes (47.6percent), oxygenated sesquiterpenes (22.2percent- 28.0percent). The major components were found to be β-caryophyllene (14.6percent- 23.0percent), α-caryophyllene (9.4percent- 18.0percent), trans- caryophyllene (12.2percent- 14.6percent), α-cedrene (26.2percent), germacrene –d-4-ol (16.8percent), 2,6-dihydroxyacetophenone (15.6percent), (+) epibicyclosesquiphellandrene (15.3percent), E-β- farnesene (13.0percent), β-phellandrene (11.7percent), 2-nitrophenol (9.5percent), palatinol (8.4percent), geranyl acetate (7.7percent) and linoleic acid (7.4percent). The oils from the wild and cultivated sources showed significant (p<0.05-0.001) decrease in number of writhes induced by the acetic acid compared to vehicle; caused significant (p<0.05-0.001) delay in reaction time on the hot plate at 60 and 90 min post-treatment and significantly (p<0.05-0.001) reduced oedema size caused by the egg albumin injection compared to the vehicle. The oils from the wild plant showed more potency compared to the cultivated. The essential oils of wild and cultivated P. inquinans showed qualitative, quantitative and chemotaxonomic variation with analgesic and anti-inflammatory activity. These essential oils need to be explored for further biological analysis because of the major components they contain.
- Full Text:
- Date Issued: 2016
The use of treated brewery effluent as a water and nutrient source in crop irrigation
- Authors: Taylor, Richard Peter
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5390 , http://hdl.handle.net/10962/d1021265
- Description: Brewery effluent (BE) needs to be treated before it can be released into the environment, reused or used in down-stream activities. Current technologies used to address this concern at the experimental wastewater treatment plant at Ibahyi Brewery (SAB Ltd) include anaerobic digestion (AD), primary facultative ponds (PFP), high rate algal ponds (HRAP) and constructed wetlands (CW). The aim of this work was to determine if BE treated in these systems might be suitable for crop irrigation. A test crop, cabbage (Brassica oleracea cv. Star 3301), grew best on post-AD and post-PFP BE compared to those irrigated with post-HRAP or post-CW effluent. However, the yield was 13% lower than cabbage plants irrigated with a commercial nutrient solution and fresh water. The relatively high conductivity (3019.05 ± 48.72 μs/cm2) of BE may be the main factor reducing the cabbage yields. Post-HRAP and post-CW BE were the least suitable for irrigated crop production due to the higher conductivity and lower nutrient content of these treated effluents. After three months, soils irrigated with post-AD and post-PFP BE had a significantly higher sodium content and sodium adsorption ratio (3919 ± 94.77 mg/kg & 8.18 ± 0.17) than soil irrigated with a commercial nutrient solution (920.58 ± 27.46 mg/kg & 2.20 ± 0.05; p<0.05). However, this was not accompanied by a deterioration in the soil’s hydro-physical properties, nor a change in the metabolic community structure of the soil (p>0.05). After prolonged irrigation with treated BE, sodium is likely to build up in the soil and this can be expected to be accompanied by a deterioration in the soil physical structure. However, crops species such as millet (Echinochloa esculenta), lucerne (Medicago sativa) and saltbush (Atriplex nummularia) reduced the build-up of sodium in the soil. The results suggest that sodium was mainly removed from the soil through plant-assisted leaching. Of the crops grown, lucerne showed the most promise because it improved the soil physical properties, is able to grow well in alkaline environments, is a popular fodder crop and can be harvested multiple times from a single stand. Brewery effluent is more suitable for soil production systems than hydroponic production systems because the soil was able to act as a buffer against the high pH of post-AD BE, whereas in a hydroponics systems the high pH reduced the availability of key minerals to plants. In conclusion brewery effluent contains sufficient plants nutrients to support the growth of cabbages, saltbush, lucerne and millet. However the sodium content of BE is a concern as it accumulates in the soil, and in the long-term it may lead to soil degradation. It is suggested that the brewery change the pH neutralising treatment of BE from sodium hydroxide to potassium hydroxide, or dolomitic lime (calcium and magnesium carbonate) because this would reduce the introduction of sodium into the system, and would increase the suitability of BE for crop production, given potassium and calcium are plant nutrients. The benefits of developing this nutrient and water resource could contribute to cost-reductions at the brewery, more efficient water, nutrient and energy management, create job opportunities with the potential of improving food security in the local community.
- Full Text:
- Date Issued: 2016
- Authors: Taylor, Richard Peter
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5390 , http://hdl.handle.net/10962/d1021265
- Description: Brewery effluent (BE) needs to be treated before it can be released into the environment, reused or used in down-stream activities. Current technologies used to address this concern at the experimental wastewater treatment plant at Ibahyi Brewery (SAB Ltd) include anaerobic digestion (AD), primary facultative ponds (PFP), high rate algal ponds (HRAP) and constructed wetlands (CW). The aim of this work was to determine if BE treated in these systems might be suitable for crop irrigation. A test crop, cabbage (Brassica oleracea cv. Star 3301), grew best on post-AD and post-PFP BE compared to those irrigated with post-HRAP or post-CW effluent. However, the yield was 13% lower than cabbage plants irrigated with a commercial nutrient solution and fresh water. The relatively high conductivity (3019.05 ± 48.72 μs/cm2) of BE may be the main factor reducing the cabbage yields. Post-HRAP and post-CW BE were the least suitable for irrigated crop production due to the higher conductivity and lower nutrient content of these treated effluents. After three months, soils irrigated with post-AD and post-PFP BE had a significantly higher sodium content and sodium adsorption ratio (3919 ± 94.77 mg/kg & 8.18 ± 0.17) than soil irrigated with a commercial nutrient solution (920.58 ± 27.46 mg/kg & 2.20 ± 0.05; p<0.05). However, this was not accompanied by a deterioration in the soil’s hydro-physical properties, nor a change in the metabolic community structure of the soil (p>0.05). After prolonged irrigation with treated BE, sodium is likely to build up in the soil and this can be expected to be accompanied by a deterioration in the soil physical structure. However, crops species such as millet (Echinochloa esculenta), lucerne (Medicago sativa) and saltbush (Atriplex nummularia) reduced the build-up of sodium in the soil. The results suggest that sodium was mainly removed from the soil through plant-assisted leaching. Of the crops grown, lucerne showed the most promise because it improved the soil physical properties, is able to grow well in alkaline environments, is a popular fodder crop and can be harvested multiple times from a single stand. Brewery effluent is more suitable for soil production systems than hydroponic production systems because the soil was able to act as a buffer against the high pH of post-AD BE, whereas in a hydroponics systems the high pH reduced the availability of key minerals to plants. In conclusion brewery effluent contains sufficient plants nutrients to support the growth of cabbages, saltbush, lucerne and millet. However the sodium content of BE is a concern as it accumulates in the soil, and in the long-term it may lead to soil degradation. It is suggested that the brewery change the pH neutralising treatment of BE from sodium hydroxide to potassium hydroxide, or dolomitic lime (calcium and magnesium carbonate) because this would reduce the introduction of sodium into the system, and would increase the suitability of BE for crop production, given potassium and calcium are plant nutrients. The benefits of developing this nutrient and water resource could contribute to cost-reductions at the brewery, more efficient water, nutrient and energy management, create job opportunities with the potential of improving food security in the local community.
- Full Text:
- Date Issued: 2016