Dominion: architecture as a symbol of authority in the Eastern Cape Colonial Frontier
- Authors: Mnyila, Desmond
- Date: 2016
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/4256 , vital:20639
- Description: My mini thesis is an exploration of architecture as part of the landscape of Grahamstown and how ideas of dominion and subordination of the non- white citizens of this town were asserted or communicated through space. I concur with theories about architectural buildings as objects that express power and reinforce power relations in any given society. Markus (1993) goes into great lengths to explain how buildings are primarily about power and town planning is a means of control. The area under consideration is very rich in history especially during the period that interested me which is the nineteenth century as this was a period of the establishment of Grahamstown, firstly, as a military establishment and then as a small town serving as a residential area for the British Settlers who arrived in 1820. Throughout the mini thesis I have unpacked the nature of power itself by referring to Njoh (2009) who refers to different categories of the use and especially the abuse or demonstration of power. It wouldn’t do justice to an area as rich in history as the area which is now referred to as the Albany to not dwell into some of the events that were played out here, some of which had consequences and implications for the rest of South Africa. After 1820, the town developed as more buildings of domestic houses, churches, houses of officials, prisons and schools were built. In the thesis I unpack the different architectural styles like the Georgian, Victorian and Cape Dutch styles that formed a significant part of this small town. I draw attention to the ideas of dominion that Njoh elucidates, which were played out in the building of the town architectural structures. Architecture demonstrated British might and power through the imposition of British and European architectural styles on an African landscape. The sheer magnitude of the buildings, I argue, was carefully planned and the use of durable materials, often stones that were imported from abroad, was a carefully orchestrated move to demonstrate British wealth and power through intimidation and seduction. Thomas Baines was one of the artists who spent some time in Grahamstown and made a series of the landscape of this town. My interest in Baines for purposes of this thesis is the manner in which he represented Grahamstown and how he was propagator of British imperialism under the guise of ‘spreading civilisation’ among the ‘back ward’ inhabitants of this continent. My painting practice is influenced by and responds to the vacant land theory especially Baines’ works which were executed to present a Grahamstown as a purely British town ‘emptying’ it of all traces of non- British non- European dwellings or citizens. My practice brings back the layers of history that I have witnessed and the painting surface is slowly built up with water metaphorically destroying the solid structures that were built in the nineteenth century in Grahamstown. As a person who has lived through apartheid and a new dispensation in South Africa, this is reflected in my paintings with a tension between aesthetically pleasing painting styles and disturbing rough surface textures. Anselm Kiefer is the artist who has influenced my work in the manner of working he prefers and also in his tendency to look back at past periods in history.
- Full Text:
- Authors: Mnyila, Desmond
- Date: 2016
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/4256 , vital:20639
- Description: My mini thesis is an exploration of architecture as part of the landscape of Grahamstown and how ideas of dominion and subordination of the non- white citizens of this town were asserted or communicated through space. I concur with theories about architectural buildings as objects that express power and reinforce power relations in any given society. Markus (1993) goes into great lengths to explain how buildings are primarily about power and town planning is a means of control. The area under consideration is very rich in history especially during the period that interested me which is the nineteenth century as this was a period of the establishment of Grahamstown, firstly, as a military establishment and then as a small town serving as a residential area for the British Settlers who arrived in 1820. Throughout the mini thesis I have unpacked the nature of power itself by referring to Njoh (2009) who refers to different categories of the use and especially the abuse or demonstration of power. It wouldn’t do justice to an area as rich in history as the area which is now referred to as the Albany to not dwell into some of the events that were played out here, some of which had consequences and implications for the rest of South Africa. After 1820, the town developed as more buildings of domestic houses, churches, houses of officials, prisons and schools were built. In the thesis I unpack the different architectural styles like the Georgian, Victorian and Cape Dutch styles that formed a significant part of this small town. I draw attention to the ideas of dominion that Njoh elucidates, which were played out in the building of the town architectural structures. Architecture demonstrated British might and power through the imposition of British and European architectural styles on an African landscape. The sheer magnitude of the buildings, I argue, was carefully planned and the use of durable materials, often stones that were imported from abroad, was a carefully orchestrated move to demonstrate British wealth and power through intimidation and seduction. Thomas Baines was one of the artists who spent some time in Grahamstown and made a series of the landscape of this town. My interest in Baines for purposes of this thesis is the manner in which he represented Grahamstown and how he was propagator of British imperialism under the guise of ‘spreading civilisation’ among the ‘back ward’ inhabitants of this continent. My painting practice is influenced by and responds to the vacant land theory especially Baines’ works which were executed to present a Grahamstown as a purely British town ‘emptying’ it of all traces of non- British non- European dwellings or citizens. My practice brings back the layers of history that I have witnessed and the painting surface is slowly built up with water metaphorically destroying the solid structures that were built in the nineteenth century in Grahamstown. As a person who has lived through apartheid and a new dispensation in South Africa, this is reflected in my paintings with a tension between aesthetically pleasing painting styles and disturbing rough surface textures. Anselm Kiefer is the artist who has influenced my work in the manner of working he prefers and also in his tendency to look back at past periods in history.
- Full Text:
Dridex: Analysis of the traffic and automatic generation of IOCs
- Rudman, Lauren, Irwin, Barry V W
- Authors: Rudman, Lauren , Irwin, Barry V W
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429525 , vital:72619 , https://ieeexplore.ieee.org/abstract/document/7802932
- Description: In this paper we present a framework that generates network Indicators of Compromise (IOC) automatically from a malware sample after dynamic runtime analysis. The framework addresses the limitations of manual Indicator of Compromise generation and utilises sandbox environment to perform the malware analysis in. We focus on the generation of network based IOCs from captured traffic files (PCAPs) generated by the dynamic malware analysis. The Cuckoo Sandbox environment is used for the analysis and the setup is described in detail. Accordingly, we discuss the concept of IOCs and the popular formats used as there is currently no standard. As an example of how the proof-of-concept framework can be used, we chose 100 Dridex malware samples and evaluated the traffic and showed what can be used for the generation of network-based IOCs. Results of our system confirm that we can create IOCs from dynamic malware analysis and avoid the legitimate background traffic originating from the sandbox system. We also briefly discuss the sharing of, and application of the generated IOCs and the number of systems that can be used to share them. Lastly we discuss how they can be useful in combating cyber threats.
- Full Text:
- Authors: Rudman, Lauren , Irwin, Barry V W
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429525 , vital:72619 , https://ieeexplore.ieee.org/abstract/document/7802932
- Description: In this paper we present a framework that generates network Indicators of Compromise (IOC) automatically from a malware sample after dynamic runtime analysis. The framework addresses the limitations of manual Indicator of Compromise generation and utilises sandbox environment to perform the malware analysis in. We focus on the generation of network based IOCs from captured traffic files (PCAPs) generated by the dynamic malware analysis. The Cuckoo Sandbox environment is used for the analysis and the setup is described in detail. Accordingly, we discuss the concept of IOCs and the popular formats used as there is currently no standard. As an example of how the proof-of-concept framework can be used, we chose 100 Dridex malware samples and evaluated the traffic and showed what can be used for the generation of network-based IOCs. Results of our system confirm that we can create IOCs from dynamic malware analysis and avoid the legitimate background traffic originating from the sandbox system. We also briefly discuss the sharing of, and application of the generated IOCs and the number of systems that can be used to share them. Lastly we discuss how they can be useful in combating cyber threats.
- Full Text:
Dung beetle (Coleoptera Scarabaeoidea) assemblages in the western Italian Alps: benchmark data for land use monitoring
- Tocco, Claudia, Villet, Martin H
- Authors: Tocco, Claudia , Villet, Martin H
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441361 , vital:73879 , 10.3897/BDJ.4.e10059
- Description: Traditional agro-pastoral practices are in decline over much of the Alps (MacDonald et al. 2000), leading to shrub and tree encroachment, and this represents one of the main threats for the conservation of alpine biodiversity, as many plant and animal species are dependent on the presence of semi-natural open habitats. However, quantifying this environmental change and assessing its impact on biodiversity may be difficult, especially in the context of sparse historical survey data. The accessibility of contemporary data about local biodiversity surveys in general, and indicator taxa in particular, is an essential consideration for planning future evaluations of conservation status in the Alps and for conservation plans that use ecological indicators to monitor temporal changes in biodiversity. Dung beetles are important ecosystem service providers (Nichols et al. 2008) that have been assessed as a good ecological indicator taxon in several studies (reviewed by Nichols and Gardner 2011), and although the Alps is perhaps one of the best-studied regions in respect of dung beetles, there are still only eight readily-accessible publications. We have augmented and comprehensively reviewed the data from these publications.
- Full Text:
- Authors: Tocco, Claudia , Villet, Martin H
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441361 , vital:73879 , 10.3897/BDJ.4.e10059
- Description: Traditional agro-pastoral practices are in decline over much of the Alps (MacDonald et al. 2000), leading to shrub and tree encroachment, and this represents one of the main threats for the conservation of alpine biodiversity, as many plant and animal species are dependent on the presence of semi-natural open habitats. However, quantifying this environmental change and assessing its impact on biodiversity may be difficult, especially in the context of sparse historical survey data. The accessibility of contemporary data about local biodiversity surveys in general, and indicator taxa in particular, is an essential consideration for planning future evaluations of conservation status in the Alps and for conservation plans that use ecological indicators to monitor temporal changes in biodiversity. Dung beetles are important ecosystem service providers (Nichols et al. 2008) that have been assessed as a good ecological indicator taxon in several studies (reviewed by Nichols and Gardner 2011), and although the Alps is perhaps one of the best-studied regions in respect of dung beetles, there are still only eight readily-accessible publications. We have augmented and comprehensively reviewed the data from these publications.
- Full Text:
Dynamic changes of soil surface organic carbon under different mulching practices in citrus orchards on sloping land
- Gu, Chiming, Liu, Yi, Mohamed, Ibrahim, Zhang, Runhua, Wang, Xiao, Nie, Xinxin, Jiang, Min, Brooks, Margot, Chen, Fang, Li, Zhiguo
- Authors: Gu, Chiming , Liu, Yi , Mohamed, Ibrahim , Zhang, Runhua , Wang, Xiao , Nie, Xinxin , Jiang, Min , Brooks, Margot , Chen, Fang , Li, Zhiguo
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:28997 , ISSN 0168384 , https://doi.org/10.1371/journal.pone.0168384
- Description: Publisher version , Mulching management has been used in many places all over the world to improve agricultural sustainability. However, the cycling of carbon in the soil under applications of mulch on sloping arable land is not yet fully understood. A four-year field experiment was carried out in Xiaofuling watershed of Danjiangkou reservoir in China. The object was to evaluate the effects of the application of straw mulch (ST) and grass mulch (GT) on dynamic changes in soil organic carbon and its fractions. Results showed that mulch applied on the soil surface increased the contents of SOC and its active fractions in the soil. Compared to the control without cover (CK), ST and GT treatments increased the contents of SOC, LOC, DOC, POC and EOC by 14.73%, 16.5%, 22.5%, 41.5% and 21%, respectively, in the 0–40 cm soil layer, and by 17%, 14%, 19%, and 30%, respectively, in the 0–100 cm soil layer. The contents of organic carbon and its active fractions decreased with increasing soil depth in all of the treatments. SOC was accumulated in the period of December to the following March. The contents of soil DOC and LOC were high in January to March, while the contents of soil POC and EOC were high in June to September. The relative contents of soil organic carbon fractions were POC > EOC > LOC > DOC over the four years. Straw mulching had no significant effect on the changes in soil organic carbon active fractions during the different periods. Based on this long-term field experiment in Danjiangkou reservoir, we found that straw mulching had a significant effect on soil, increasing SOC content and stock in slopping arable land, and that live grass mulching was more effective than rice straw mulching. We discuss possible optimal periods for the implementation of mulching practices on sloping land.
- Full Text:
- Authors: Gu, Chiming , Liu, Yi , Mohamed, Ibrahim , Zhang, Runhua , Wang, Xiao , Nie, Xinxin , Jiang, Min , Brooks, Margot , Chen, Fang , Li, Zhiguo
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:28997 , ISSN 0168384 , https://doi.org/10.1371/journal.pone.0168384
- Description: Publisher version , Mulching management has been used in many places all over the world to improve agricultural sustainability. However, the cycling of carbon in the soil under applications of mulch on sloping arable land is not yet fully understood. A four-year field experiment was carried out in Xiaofuling watershed of Danjiangkou reservoir in China. The object was to evaluate the effects of the application of straw mulch (ST) and grass mulch (GT) on dynamic changes in soil organic carbon and its fractions. Results showed that mulch applied on the soil surface increased the contents of SOC and its active fractions in the soil. Compared to the control without cover (CK), ST and GT treatments increased the contents of SOC, LOC, DOC, POC and EOC by 14.73%, 16.5%, 22.5%, 41.5% and 21%, respectively, in the 0–40 cm soil layer, and by 17%, 14%, 19%, and 30%, respectively, in the 0–100 cm soil layer. The contents of organic carbon and its active fractions decreased with increasing soil depth in all of the treatments. SOC was accumulated in the period of December to the following March. The contents of soil DOC and LOC were high in January to March, while the contents of soil POC and EOC were high in June to September. The relative contents of soil organic carbon fractions were POC > EOC > LOC > DOC over the four years. Straw mulching had no significant effect on the changes in soil organic carbon active fractions during the different periods. Based on this long-term field experiment in Danjiangkou reservoir, we found that straw mulching had a significant effect on soil, increasing SOC content and stock in slopping arable land, and that live grass mulching was more effective than rice straw mulching. We discuss possible optimal periods for the implementation of mulching practices on sloping land.
- Full Text:
Détournement : the art of troubling
- Authors: Wilby, Mark Owen
- Date: 2016
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/345 , vital:19950
- Description: Confidence in the form of, for example, commodified debt or the commodification of future value, is an increasingly large part of today’s globalised economy. This was alarmingly illustrated in 2008 by the repercussions of marketing unstable debt in the form of subprime mortgages in the United States leading to a precipitous global financial meltdown. That was a collapse of confidence writ large. At the same time, confidence is also a cornerstone of everyday social and professional life. The non-ZERO-sum project (exhibition title of practical submission in MFA fulfilment) interacts with the notion of confidence, and more particularly economic confidence. At the same time, the project takes the view that engagement from a fine art perspective would have an inherently inadequate vocabulary if restricted to a representative practice, and so a more interactive approach was sought. Research into the radical activism of the Situationists in the 1950s and 1960s, and particularly their tactic of détournement (the deliberate subversion of social or cultural practices), has informed and influenced the development of an interventionist technique summed up in this thesis as: The Art of Troubling. The Situationists had a dichotomous relationship with art. The group was initially made up mostly of artists and is in other instances referred to as an art movement. They saw art as the fulcrum for social and political change, and had their roots in the Dada, Surrealist, and Lettrist movements. As such, they also carried the genes of the notion of an anti-art, which varied in concept between art as a disruptive and propagandistic practice to the subsuming of art into other forms of social activity. This thesis, Détournement: The Art of Troubling, describes non-ZERO-sum as a bespoke methodology designed specifically for engagement with its particular topic. As such, the concept does not necessarily follow a template for situationist intervention. In 1962, a growing rift between the artists and the political theorists within the Situationist International tore the group in two. In conclusion of the non-ZERO-sum project, this thesis offers the observation that perhaps it was the political faction of the Situationists that had a more compelling idea of an art that functions through its very own subsumption.
- Full Text:
- Authors: Wilby, Mark Owen
- Date: 2016
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/345 , vital:19950
- Description: Confidence in the form of, for example, commodified debt or the commodification of future value, is an increasingly large part of today’s globalised economy. This was alarmingly illustrated in 2008 by the repercussions of marketing unstable debt in the form of subprime mortgages in the United States leading to a precipitous global financial meltdown. That was a collapse of confidence writ large. At the same time, confidence is also a cornerstone of everyday social and professional life. The non-ZERO-sum project (exhibition title of practical submission in MFA fulfilment) interacts with the notion of confidence, and more particularly economic confidence. At the same time, the project takes the view that engagement from a fine art perspective would have an inherently inadequate vocabulary if restricted to a representative practice, and so a more interactive approach was sought. Research into the radical activism of the Situationists in the 1950s and 1960s, and particularly their tactic of détournement (the deliberate subversion of social or cultural practices), has informed and influenced the development of an interventionist technique summed up in this thesis as: The Art of Troubling. The Situationists had a dichotomous relationship with art. The group was initially made up mostly of artists and is in other instances referred to as an art movement. They saw art as the fulcrum for social and political change, and had their roots in the Dada, Surrealist, and Lettrist movements. As such, they also carried the genes of the notion of an anti-art, which varied in concept between art as a disruptive and propagandistic practice to the subsuming of art into other forms of social activity. This thesis, Détournement: The Art of Troubling, describes non-ZERO-sum as a bespoke methodology designed specifically for engagement with its particular topic. As such, the concept does not necessarily follow a template for situationist intervention. In 1962, a growing rift between the artists and the political theorists within the Situationist International tore the group in two. In conclusion of the non-ZERO-sum project, this thesis offers the observation that perhaps it was the political faction of the Situationists that had a more compelling idea of an art that functions through its very own subsumption.
- Full Text:
E-governance in the public sector : a case study of the central admission system in Tanzania
- Authors: Mahundu, Fabian G
- Date: 2016
- Subjects: Universities and colleges -- Tanzania -- Admission , Universities and colleges -- Tanzania -- Entrance requirements , Education, Higher -- Tanzania , Information technology -- Social aspects -- Tanzania.
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3409 , http://hdl.handle.net/10962/d1020845
- Description: This thesis sets out to answer the following central research question: what are the influences, challenges, benefits and costs of the Central Admission System (CAS) as an e-Governance initiative in improving undergraduates’ admissions service delivery and quality assurance in Tanzania’s higher education institutions?’ In answering this key question, three sub-questions were explored: (1) To what extent and in what ways does the implementation of the CAS influence the organisation of admissions work and workplace relations in higher education institutions? (2) What are the sociotechnical challenges of implementing the CAS? (3) What are the advantages of the CAS in improving admissions service delivery and quality assurance in higher education institutions? The sociotechnical theoretical framework is an ideal for exploring these issues as it accommodates the understanding of dual relationship between social and technological aspects of the CAS in line with the contextual issues in its implementation. The focus of the thesis is on Tanzania’s higher education institutions where the CAS is being implemented. The study is informed by data collected through interviews and documentary analysis. Data organization and analysis was done using NVivo 10 QSR software. The study demonstrates that, notwithstanding the fast development and uptake of Information and Communication Technologies (ICTs), the implementation of the CAS in Tanzania is hampered by the fact that most of the end-users of CAS (particularly applicants) have relatively low access to the ICT infrastructure. Several factors continue to have a significant effect on the implementation of CAS, which in turn lead to implications for the uptake of improved admissions service delivery and quality assurance. A digital divide, resistance to change by some higher education institutions (HEIs), poor ICT skills among applicants, the costs of internet services, unreliable electricity supply, and inadequate IT experts continue to frustrate the objective of improved admissions service delivery and quality assurance. As a technological innovation in the workplace, the CAS has led to a restructuring of admissions work tasks among admissions officers, a need to review job descriptions, introduced tighter controls over admission work processes, and has shaped admission workers’ professional identities and self-presentations.
- Full Text:
- Authors: Mahundu, Fabian G
- Date: 2016
- Subjects: Universities and colleges -- Tanzania -- Admission , Universities and colleges -- Tanzania -- Entrance requirements , Education, Higher -- Tanzania , Information technology -- Social aspects -- Tanzania.
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3409 , http://hdl.handle.net/10962/d1020845
- Description: This thesis sets out to answer the following central research question: what are the influences, challenges, benefits and costs of the Central Admission System (CAS) as an e-Governance initiative in improving undergraduates’ admissions service delivery and quality assurance in Tanzania’s higher education institutions?’ In answering this key question, three sub-questions were explored: (1) To what extent and in what ways does the implementation of the CAS influence the organisation of admissions work and workplace relations in higher education institutions? (2) What are the sociotechnical challenges of implementing the CAS? (3) What are the advantages of the CAS in improving admissions service delivery and quality assurance in higher education institutions? The sociotechnical theoretical framework is an ideal for exploring these issues as it accommodates the understanding of dual relationship between social and technological aspects of the CAS in line with the contextual issues in its implementation. The focus of the thesis is on Tanzania’s higher education institutions where the CAS is being implemented. The study is informed by data collected through interviews and documentary analysis. Data organization and analysis was done using NVivo 10 QSR software. The study demonstrates that, notwithstanding the fast development and uptake of Information and Communication Technologies (ICTs), the implementation of the CAS in Tanzania is hampered by the fact that most of the end-users of CAS (particularly applicants) have relatively low access to the ICT infrastructure. Several factors continue to have a significant effect on the implementation of CAS, which in turn lead to implications for the uptake of improved admissions service delivery and quality assurance. A digital divide, resistance to change by some higher education institutions (HEIs), poor ICT skills among applicants, the costs of internet services, unreliable electricity supply, and inadequate IT experts continue to frustrate the objective of improved admissions service delivery and quality assurance. As a technological innovation in the workplace, the CAS has led to a restructuring of admissions work tasks among admissions officers, a need to review job descriptions, introduced tighter controls over admission work processes, and has shaped admission workers’ professional identities and self-presentations.
- Full Text:
E-Government as a Means to Support Communal, Large ICT Infrastructure in Poor Areas
- Gumbo, Sibukelo, Terzoli, Alfredo, Tsietsi, Mosiuoa
- Authors: Gumbo, Sibukelo , Terzoli, Alfredo , Tsietsi, Mosiuoa
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431287 , vital:72761 , https://www.academic-bookshop.com/ourshop/prod_5067238-ECEG-2016-Proceedings-of-the-16th-European-Conference-on-eGovernment.html
- Description: Citizen-facing e-Government appears inevitable given current technol-ogy trends, and certainly has many advantages. One overlooked bene-fit, in our opinion, is its potential to make financially viable communal “large ICT” installations, which would diffuse ICT in poor communities where ICT is currently absent.(By “large ICT” we refer to end-user equipment such as desktops or laptops, on which would be possible to produce content, including software. The presence of “large ICT” in a community is critical in our opinion for the empowerment of the commu-nity, especially its younger component.) This paper explores this poten-tial in e-Government, describing a model conceptualized in the Siyakhu-la Living Lab in South Africa and partially implemented, through an inte-gration platform named “TeleWeaver”. The model behind TeleWeaver is an adaptation of the classic Internet business model-whereby users of services do not directly pay for the services they use. This model is especially relevant currently in South Africa, because of the an-nouncement by the government to pilot connecting to the internet gov-ernment facilities, including schools, in eight poor district municipalities.
- Full Text:
- Authors: Gumbo, Sibukelo , Terzoli, Alfredo , Tsietsi, Mosiuoa
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431287 , vital:72761 , https://www.academic-bookshop.com/ourshop/prod_5067238-ECEG-2016-Proceedings-of-the-16th-European-Conference-on-eGovernment.html
- Description: Citizen-facing e-Government appears inevitable given current technol-ogy trends, and certainly has many advantages. One overlooked bene-fit, in our opinion, is its potential to make financially viable communal “large ICT” installations, which would diffuse ICT in poor communities where ICT is currently absent.(By “large ICT” we refer to end-user equipment such as desktops or laptops, on which would be possible to produce content, including software. The presence of “large ICT” in a community is critical in our opinion for the empowerment of the commu-nity, especially its younger component.) This paper explores this poten-tial in e-Government, describing a model conceptualized in the Siyakhu-la Living Lab in South Africa and partially implemented, through an inte-gration platform named “TeleWeaver”. The model behind TeleWeaver is an adaptation of the classic Internet business model-whereby users of services do not directly pay for the services they use. This model is especially relevant currently in South Africa, because of the an-nouncement by the government to pilot connecting to the internet gov-ernment facilities, including schools, in eight poor district municipalities.
- Full Text:
Ecological engineering on rocky shores: grazing, predation, nutrient availability and their influence on epifaunal communities
- Authors: Ndhlovu, Aldwin
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3453 , vital:20500
- Description: “Ecosystem engineers modify, create/destroy habitat and directly/indirectly modulate availability of resources to other species by causing physical state changes to biotic and abiotic materials” (Jones et al, 1994, page 1). Previous studies have analysed top-down and bottom-up relationships to determine which form of regulation is key in controlling community composition. This study assessed the direct and indirect effects of top down and bottom up factors on the epifaunal communities of macro-algae. Epifauna are subject to the direct top-down effects of predation and bottom up effects of habitat availability. Habitat availability in turn experiences the direct top down effects of grazing and bottom up effects of nutrient availability due to upwelling. Grazing and upwelling may therefore have indirect effects on macro-algal epifauna. Four treatments (Procedural controls, Controls, Predator or Grazer exclusion) set out in a block design (n = 5) were monitored monthly for algal cover of the substratum for 12 months with the surface area of algal plants and epifaunal species composition and abundances assessed at the end of the experiment. The red alga Gelidium pristoides was selected as the ecosystem engineer as it is common, supports a diverse community of epiphytic animals and acts as a nursery for small epifaunal organisms. The experiment was run at two upwelling sites interspersed with two non-upwelling sites. Sites were separated on scales of 100km along approximately 500km of coastline. Dipping whole algae in dish washing liquid provided a strong relationship between their surface area and the weight of the film of dish washing liquid covering them. Surface area was strongly correlated to dry weight but neither surface area nor dry weight was correlated to algal cover of the substratum. Algal cover was influenced by the interactions of treatment with site (nested in upwelling) and upwelling. At all sites, treatments that allowed access to grazers, Grazer + and Control treatments, showed no significant differences and these two treatments had lower algal cover than Predator + and Closed treatments which did not differ from one another 3 [Grazer + = Control < Predator + = Closed]. A total of 44 epifaunal species were identified, with the predominant orders being Amphipoda and Isopoda. Primer results showed that only site had a significant effect on species composition, with sites that were further apart being more different. Site (nested in upwelling) had an effect on total epifaunal abundances when data were non-normalised. When total epifaunal abundances were normalised for algal cover of the substratum or algal surface area to provide density data, predation had no significant effect. Grazing did have a significant effect, but only when data were normalised to algal surface area, not cover, leading to the conclusion that indirect top-down factors through grazing of the sea weed are important in structuring epifaunal communities depending on how habitat availability is measured.
- Full Text:
- Authors: Ndhlovu, Aldwin
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3453 , vital:20500
- Description: “Ecosystem engineers modify, create/destroy habitat and directly/indirectly modulate availability of resources to other species by causing physical state changes to biotic and abiotic materials” (Jones et al, 1994, page 1). Previous studies have analysed top-down and bottom-up relationships to determine which form of regulation is key in controlling community composition. This study assessed the direct and indirect effects of top down and bottom up factors on the epifaunal communities of macro-algae. Epifauna are subject to the direct top-down effects of predation and bottom up effects of habitat availability. Habitat availability in turn experiences the direct top down effects of grazing and bottom up effects of nutrient availability due to upwelling. Grazing and upwelling may therefore have indirect effects on macro-algal epifauna. Four treatments (Procedural controls, Controls, Predator or Grazer exclusion) set out in a block design (n = 5) were monitored monthly for algal cover of the substratum for 12 months with the surface area of algal plants and epifaunal species composition and abundances assessed at the end of the experiment. The red alga Gelidium pristoides was selected as the ecosystem engineer as it is common, supports a diverse community of epiphytic animals and acts as a nursery for small epifaunal organisms. The experiment was run at two upwelling sites interspersed with two non-upwelling sites. Sites were separated on scales of 100km along approximately 500km of coastline. Dipping whole algae in dish washing liquid provided a strong relationship between their surface area and the weight of the film of dish washing liquid covering them. Surface area was strongly correlated to dry weight but neither surface area nor dry weight was correlated to algal cover of the substratum. Algal cover was influenced by the interactions of treatment with site (nested in upwelling) and upwelling. At all sites, treatments that allowed access to grazers, Grazer + and Control treatments, showed no significant differences and these two treatments had lower algal cover than Predator + and Closed treatments which did not differ from one another 3 [Grazer + = Control < Predator + = Closed]. A total of 44 epifaunal species were identified, with the predominant orders being Amphipoda and Isopoda. Primer results showed that only site had a significant effect on species composition, with sites that were further apart being more different. Site (nested in upwelling) had an effect on total epifaunal abundances when data were non-normalised. When total epifaunal abundances were normalised for algal cover of the substratum or algal surface area to provide density data, predation had no significant effect. Grazing did have a significant effect, but only when data were normalised to algal surface area, not cover, leading to the conclusion that indirect top-down factors through grazing of the sea weed are important in structuring epifaunal communities depending on how habitat availability is measured.
- Full Text:
Ecological knowledge among communities, managers and scientists: Bridging divergent perspectives to improve forest management outcomes
- Rist, Lucy, Shackleton, Charlie M, Gadamus, Lily, Chapin, F Stuart, Made Gowda, C, Setty, Siddappa R, Kannan, Ramesh, Shaanker, Ramanan Uma
- Authors: Rist, Lucy , Shackleton, Charlie M , Gadamus, Lily , Chapin, F Stuart , Made Gowda, C , Setty, Siddappa R , Kannan, Ramesh , Shaanker, Ramanan Uma
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182124 , vital:43802 , xlink:href="https://doi.org/10.1007/s00267-015-0647-1"
- Description: Multiple actors are typically involved in forest management, namely communities, managers and researchers. In such cases, suboptimal management outcomes may, in addition to other factors, be symptomatic of a divergence in perspectives among these actors driven by fundamental differences in ecological knowledge. We examine the degree of congruence between the understandings of actors surrounding key issues of management concern in three case studies from tropical, subtropical and boreal forests. We identify commonly encountered points of divergence in ecological knowledge relating to key management processes and issues. We use these to formulate seven hypotheses about differences in the bodies of knowledge that frequently underlie communication and learning failures in forest management contexts where multiple actors are involved and outcomes are judged to be suboptimal. Finally, we present a set of propositions to acknowledge and narrow these differences. A more complete recognition of the full triangulation between all actors involved, and of the influence that fundamental differences in ecological knowledge can exert, may help lead to a more fruitful integration between local knowledge and practice, manager knowledge and practice, and contemporary science in forest management.
- Full Text:
- Authors: Rist, Lucy , Shackleton, Charlie M , Gadamus, Lily , Chapin, F Stuart , Made Gowda, C , Setty, Siddappa R , Kannan, Ramesh , Shaanker, Ramanan Uma
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182124 , vital:43802 , xlink:href="https://doi.org/10.1007/s00267-015-0647-1"
- Description: Multiple actors are typically involved in forest management, namely communities, managers and researchers. In such cases, suboptimal management outcomes may, in addition to other factors, be symptomatic of a divergence in perspectives among these actors driven by fundamental differences in ecological knowledge. We examine the degree of congruence between the understandings of actors surrounding key issues of management concern in three case studies from tropical, subtropical and boreal forests. We identify commonly encountered points of divergence in ecological knowledge relating to key management processes and issues. We use these to formulate seven hypotheses about differences in the bodies of knowledge that frequently underlie communication and learning failures in forest management contexts where multiple actors are involved and outcomes are judged to be suboptimal. Finally, we present a set of propositions to acknowledge and narrow these differences. A more complete recognition of the full triangulation between all actors involved, and of the influence that fundamental differences in ecological knowledge can exert, may help lead to a more fruitful integration between local knowledge and practice, manager knowledge and practice, and contemporary science in forest management.
- Full Text:
Economic evaluation of water loss saving due to the biological control of water hyacinth at New Year’s Dam, Eastern Cape province, South Africa
- Fraser, Gavin C G, Hill, Martin P, Martin, J A
- Authors: Fraser, Gavin C G , Hill, Martin P , Martin, J A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69341 , vital:29502 , https://doi.org/10.2989/16085914.2016.1151765
- Description: Water hyacinth Eichhornia crassipes is considered the most damaging aquatic weed in the world. However, few studies have quantified the impact of this weed economically and ecologically, and even fewer studies have quantified the benefits of its control. This paper focuses on water loss saving as the benefit derived from biological control of this plant between 1990 and 2013 at New Year’s Dam, Alicedale, Eastern Cape, South Africa. Estimates of water loss due to evapotranspiration from water hyacinth vary significantly; therefore, the study used three different rates, high, medium and low. A conservative raw agriculture value of R 0.26 per m3 was used to calculate the benefits derived by the water saved. The present benefit and cost values were determined using 10% and 5% discount rates. The benefit/cost ratio at the low evapotranspiration rate was less than one, implying that biological control was not economically viable but, at the higher evapotranspiration rates, the return justified the costs of biological control. However, at the marginal value product of water, the inclusion of the costs of damage to infrastructure, or the adverse effects of water hyacinth on biodiversity, would justify the use of biological control, even at the low transpiration rate.
- Full Text: false
- Authors: Fraser, Gavin C G , Hill, Martin P , Martin, J A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69341 , vital:29502 , https://doi.org/10.2989/16085914.2016.1151765
- Description: Water hyacinth Eichhornia crassipes is considered the most damaging aquatic weed in the world. However, few studies have quantified the impact of this weed economically and ecologically, and even fewer studies have quantified the benefits of its control. This paper focuses on water loss saving as the benefit derived from biological control of this plant between 1990 and 2013 at New Year’s Dam, Alicedale, Eastern Cape, South Africa. Estimates of water loss due to evapotranspiration from water hyacinth vary significantly; therefore, the study used three different rates, high, medium and low. A conservative raw agriculture value of R 0.26 per m3 was used to calculate the benefits derived by the water saved. The present benefit and cost values were determined using 10% and 5% discount rates. The benefit/cost ratio at the low evapotranspiration rate was less than one, implying that biological control was not economically viable but, at the higher evapotranspiration rates, the return justified the costs of biological control. However, at the marginal value product of water, the inclusion of the costs of damage to infrastructure, or the adverse effects of water hyacinth on biodiversity, would justify the use of biological control, even at the low transpiration rate.
- Full Text: false
Editorial
- Schudel, Ingrid J, Le Grange, Lesley, Reddy, Chris
- Authors: Schudel, Ingrid J , Le Grange, Lesley , Reddy, Chris
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387193 , vital:68214 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/167508"
- Description: The unprecedented levels of human influence on the global enviroment have drawn the attention of scientists to the extent that in 2002, the Nobel Laureate, Paul Crutzen, helped in postulating a new geological epoch named the Anthropocene (Crutzen, 2002). This idea is not new and Crutzen describes an observation by an Italian geologist named Antonio Stoppani who, in 1873, spoke about an 'anthropozoic era'. Stoppani described this era as a 'new telluric force which in power and universality may be compared to the greater forces of earth' (Stoppani, 1873 in Crutzen, 2002).
- Full Text: false
- Authors: Schudel, Ingrid J , Le Grange, Lesley , Reddy, Chris
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387193 , vital:68214 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/167508"
- Description: The unprecedented levels of human influence on the global enviroment have drawn the attention of scientists to the extent that in 2002, the Nobel Laureate, Paul Crutzen, helped in postulating a new geological epoch named the Anthropocene (Crutzen, 2002). This idea is not new and Crutzen describes an observation by an Italian geologist named Antonio Stoppani who, in 1873, spoke about an 'anthropozoic era'. Stoppani described this era as a 'new telluric force which in power and universality may be compared to the greater forces of earth' (Stoppani, 1873 in Crutzen, 2002).
- Full Text: false
Effect of lipid inclusion levels in aquafeed on carcass composition, quality change during storage and nutrient excretion in dusky kob (Argyrosomus japonicus)
- Authors: Ginindza, Nhlanhla Joseph
- Date: 2016
- Subjects: Aquaculture
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5387 , http://hdl.handle.net/10962/d1020854
- Description: Dusky kob, Argyrosomus japonicus, is an aquaculture species in South Africa that is in pilot commercial production. While the major nutrient requirements of the species are known, the advantages of incorporating formulated feeds into the diet of the species has yet to be fully explored. Research on formulated feed composition is required to: minimise input costs; improve the organoleptic properties and meat quality; and minimise nutrient loss, which contributes to environmental pollution. This study sought to test the impact of different lipid levels in aquafeeds fed to dusky kob juveniles by determining: (i) growth performance, feeding efficiency, proximate and fatty acid composition; (ii) chemical changes and shelf-life of refrigerated fish fillets; and (iii) metabolic rates and nitrogen excretion of juvenile dusky kob. And more...
- Full Text:
- Authors: Ginindza, Nhlanhla Joseph
- Date: 2016
- Subjects: Aquaculture
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5387 , http://hdl.handle.net/10962/d1020854
- Description: Dusky kob, Argyrosomus japonicus, is an aquaculture species in South Africa that is in pilot commercial production. While the major nutrient requirements of the species are known, the advantages of incorporating formulated feeds into the diet of the species has yet to be fully explored. Research on formulated feed composition is required to: minimise input costs; improve the organoleptic properties and meat quality; and minimise nutrient loss, which contributes to environmental pollution. This study sought to test the impact of different lipid levels in aquafeeds fed to dusky kob juveniles by determining: (i) growth performance, feeding efficiency, proximate and fatty acid composition; (ii) chemical changes and shelf-life of refrigerated fish fillets; and (iii) metabolic rates and nitrogen excretion of juvenile dusky kob. And more...
- Full Text:
Effects of pluronic silica nanoparticles on the photophysical and photodynamic therapy behavior of triphenyl-p-phenoxy benzoic acid metalloporphyrins
- Managa, Muthumuni, Britton, Jonathan, Prinsloo, Earl, Nyokong, Tebello
- Authors: Managa, Muthumuni , Britton, Jonathan , Prinsloo, Earl , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239698 , vital:50756 , xlink:href="https://doi.org/10.1080/00958972.2016.1236372"
- Description: 5, 10, 15, Triphenyl-20-p-phenoxy benzoic acid porphyrins (P) containing Zn (ZnP), Ga (GaP), and Si (SiP) were synthesized and conjugated to pluronic-silica (PluS) nanoparticles (NPs) where the fluorescence and singlet oxygen generating behavior of the porphyrins were investigated. The highest singlet oxygen quantum yield (ΦΔ) was obtained for ZnP. When the porphyrins were conjugated to the PluS NPs, the ΦΔ was quenched and fluorescence was enhanced. The pore size of the NPs upon conjugation decreased from 18.9 nm for PluS NPs to 2.4 nm (for ZnP as an example) as determined by applying the Brunauer–Emmett–Teller method. The porphyrin complexes and their conjugates were tested for their photodynamic therapy (PDT) activity on MCF-7 breast cancer cells. It was found that ZnP and its conjugate showed the highest PDT activity. The p > 0.05 indicated that ZnP is significantly different than GaP and SiP.
- Full Text:
- Authors: Managa, Muthumuni , Britton, Jonathan , Prinsloo, Earl , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239698 , vital:50756 , xlink:href="https://doi.org/10.1080/00958972.2016.1236372"
- Description: 5, 10, 15, Triphenyl-20-p-phenoxy benzoic acid porphyrins (P) containing Zn (ZnP), Ga (GaP), and Si (SiP) were synthesized and conjugated to pluronic-silica (PluS) nanoparticles (NPs) where the fluorescence and singlet oxygen generating behavior of the porphyrins were investigated. The highest singlet oxygen quantum yield (ΦΔ) was obtained for ZnP. When the porphyrins were conjugated to the PluS NPs, the ΦΔ was quenched and fluorescence was enhanced. The pore size of the NPs upon conjugation decreased from 18.9 nm for PluS NPs to 2.4 nm (for ZnP as an example) as determined by applying the Brunauer–Emmett–Teller method. The porphyrin complexes and their conjugates were tested for their photodynamic therapy (PDT) activity on MCF-7 breast cancer cells. It was found that ZnP and its conjugate showed the highest PDT activity. The p > 0.05 indicated that ZnP is significantly different than GaP and SiP.
- Full Text:
Effects of substrate on essential fatty acids produced by phytobenthos in an austral temperate river system
- Dalu, Tatenda, Galloway, Aaron W E, Richoux, Nicole B, Froneman, P William
- Authors: Dalu, Tatenda , Galloway, Aaron W E , Richoux, Nicole B , Froneman, P William
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68002 , vital:29179 , https://doi.org/10.1086/688698
- Description: Publisher version , Aquatic and riparian habitats increasingly are affected by anthropogenic stressors, but the effects of these stressors on the nutritional quality of primary producers are often unknown. We compared essential fatty acids (EFAs) in the phytobenthos (benthic algae) growing on different substrate types (bricks, clay tiles, rocks, macrophytes, and sediments) at 2 river sites subject to differing anthropogenic stressors (using nutrient concentration as a proxy) in a temperate southern hemisphere location. We hypothesized that the fatty acid (FA) content of phytobenthos changes in response to shifts in local nutrient availability but not substrate type. EFA content (18∶2ω6, 18∶3ω3, 20∶4ω6, 20∶5ω3, and 22∶6ω3) in the phytobenthos differed overall among substrates, sites, and seasons and was generally greater in summer than in autumn and winter. EFA content was significantly greater on artificial than natural substrates and was greater at the nutrient-enriched downstream site than at the upstream site. The response of EFA content at the downstream site suggests that land use affected the synthesis of EFAs by phytobenthos and, hence, food quality for aquatic consumers. These findings indicate a potential link between physical factors, such as substrate availability and land management, and the quality of basal food resources available to primary consumers in aquatic food webs.
- Full Text: false
- Authors: Dalu, Tatenda , Galloway, Aaron W E , Richoux, Nicole B , Froneman, P William
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68002 , vital:29179 , https://doi.org/10.1086/688698
- Description: Publisher version , Aquatic and riparian habitats increasingly are affected by anthropogenic stressors, but the effects of these stressors on the nutritional quality of primary producers are often unknown. We compared essential fatty acids (EFAs) in the phytobenthos (benthic algae) growing on different substrate types (bricks, clay tiles, rocks, macrophytes, and sediments) at 2 river sites subject to differing anthropogenic stressors (using nutrient concentration as a proxy) in a temperate southern hemisphere location. We hypothesized that the fatty acid (FA) content of phytobenthos changes in response to shifts in local nutrient availability but not substrate type. EFA content (18∶2ω6, 18∶3ω3, 20∶4ω6, 20∶5ω3, and 22∶6ω3) in the phytobenthos differed overall among substrates, sites, and seasons and was generally greater in summer than in autumn and winter. EFA content was significantly greater on artificial than natural substrates and was greater at the nutrient-enriched downstream site than at the upstream site. The response of EFA content at the downstream site suggests that land use affected the synthesis of EFAs by phytobenthos and, hence, food quality for aquatic consumers. These findings indicate a potential link between physical factors, such as substrate availability and land management, and the quality of basal food resources available to primary consumers in aquatic food webs.
- Full Text: false
Effects of the biocontrol agent, coelocephalapion camarae kissinger, galling on petiole tissues, plant growth and stored reserves in plant parts of two lantana camara L.(verbenaceae) varieties
- Authors: Kistensamy, Yoganambal
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3126 , vital:20372
- Description: The agent evaluated in this study, Coelocephalapion camarae Kissinger (Brentidae), a petiole galling apionid, was released against Lantana camara L. (Verbenaceae) in South Africa and has the potential to significantly contribute to the control of this noxious weed. An important aspect of evaluating the effectiveness of a biocontrol agent; include the understanding of the mechanism in which the biocontrol agent causes damage to the plant and the plant’s response to this damage. Another aspect that was considered in evaluating the effects of the apionid was the varietal differences that exist within the weedy L. camara complex. Larval feeding of C. camarae damaged the tissue in the petioles causing gall formation and this was quantified on two common South African L. camara varieties (017 and 018). Up to 100% of the vascular tissue (xylem and phloem) of effected petioles was eaten by larvae, 25 days after ovipostion in both the L. camara varieties, effectively severing the vascular connection from the leaves. The effect of feeding and galling by different population densities of C. camarae, on biomass and total soluble sugar and starch concentrations of different plant parts was measured on these two varieties during autumn, and compared to a similar study, done during summer. Relatively low galling percentages were achieved in the experiments of this study. Plant growth was less affected by apionid feeding at similar galling levels, as higher galling densities in these trials were similar to those at low exposures in trials by Baars (2002). The dry weights of all individual and combined plant parts for lantana variety 017 was less for both adult density exposures after 70 days compared to the weights of its controls, although not statistically significant at P>0.05 The opposite effect, though barely noticeable was recorded for lantana variety 018; here, the dry weights of individual plant parts and as whole plants weighed more in the plants exposed to both densities of weevil feeding and galling after 70 days, compared to its controls. Coelocephalapion camarae herbivory may thus be more effective in inflicting damage on some L. camara varieties compared to others. The effects of late season carbohydrate storage revealed that, from early- to mid-autumn starch concentrations increased significantly in stems of both L. camara varieties and L. camara var. 018 had larger starch reserves for winter. In L. camara var. 018 stems, starch increased 52 times and concentrations doubled in stems of L. camara var 017. The increase in the sugar and decrease in starch concentrations in leaves of plants of both varieties exposed to apionids in this study was attributed to a possible reduction of available nitrogen and phosphorus, due to apionid feeding, whilst starch was reallocated within the plants to stems and roots. The increase in starch concentrations in stems of plants that were exposed to apionids may have been expected, as compensation for herbivory has been associated with, increases in photosynthetic rates and the mobilization of stored resources. Herbivory by the apionid early in the growing season may be easily compensated for by L. camara as there are nutrient flushes experienced by plants that allows the maximum uptake of nutrients facilitating recovery, whereas later in the season plants suffer lower nutrient availability and don’t recover so readily. Both early and late in the season the accumulated effects of C. camarae feeding over time will undoubtedly decrease fitness of most lantana varieties.
- Full Text:
- Authors: Kistensamy, Yoganambal
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3126 , vital:20372
- Description: The agent evaluated in this study, Coelocephalapion camarae Kissinger (Brentidae), a petiole galling apionid, was released against Lantana camara L. (Verbenaceae) in South Africa and has the potential to significantly contribute to the control of this noxious weed. An important aspect of evaluating the effectiveness of a biocontrol agent; include the understanding of the mechanism in which the biocontrol agent causes damage to the plant and the plant’s response to this damage. Another aspect that was considered in evaluating the effects of the apionid was the varietal differences that exist within the weedy L. camara complex. Larval feeding of C. camarae damaged the tissue in the petioles causing gall formation and this was quantified on two common South African L. camara varieties (017 and 018). Up to 100% of the vascular tissue (xylem and phloem) of effected petioles was eaten by larvae, 25 days after ovipostion in both the L. camara varieties, effectively severing the vascular connection from the leaves. The effect of feeding and galling by different population densities of C. camarae, on biomass and total soluble sugar and starch concentrations of different plant parts was measured on these two varieties during autumn, and compared to a similar study, done during summer. Relatively low galling percentages were achieved in the experiments of this study. Plant growth was less affected by apionid feeding at similar galling levels, as higher galling densities in these trials were similar to those at low exposures in trials by Baars (2002). The dry weights of all individual and combined plant parts for lantana variety 017 was less for both adult density exposures after 70 days compared to the weights of its controls, although not statistically significant at P>0.05 The opposite effect, though barely noticeable was recorded for lantana variety 018; here, the dry weights of individual plant parts and as whole plants weighed more in the plants exposed to both densities of weevil feeding and galling after 70 days, compared to its controls. Coelocephalapion camarae herbivory may thus be more effective in inflicting damage on some L. camara varieties compared to others. The effects of late season carbohydrate storage revealed that, from early- to mid-autumn starch concentrations increased significantly in stems of both L. camara varieties and L. camara var. 018 had larger starch reserves for winter. In L. camara var. 018 stems, starch increased 52 times and concentrations doubled in stems of L. camara var 017. The increase in the sugar and decrease in starch concentrations in leaves of plants of both varieties exposed to apionids in this study was attributed to a possible reduction of available nitrogen and phosphorus, due to apionid feeding, whilst starch was reallocated within the plants to stems and roots. The increase in starch concentrations in stems of plants that were exposed to apionids may have been expected, as compensation for herbivory has been associated with, increases in photosynthetic rates and the mobilization of stored resources. Herbivory by the apionid early in the growing season may be easily compensated for by L. camara as there are nutrient flushes experienced by plants that allows the maximum uptake of nutrients facilitating recovery, whereas later in the season plants suffer lower nutrient availability and don’t recover so readily. Both early and late in the season the accumulated effects of C. camarae feeding over time will undoubtedly decrease fitness of most lantana varieties.
- Full Text:
Effects of the invasive shrub, Lantana camara, on soil properties in the Eastern Cape, South Africa
- Ruwanza, Sheunesu, Shackleton, Charlie M
- Authors: Ruwanza, Sheunesu , Shackleton, Charlie M
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180459 , vital:43391 , xlink:href="https://doi.org/10.1111/wbm.12094"
- Description: Lantana camara L. is an invasive alien shrub of worldwide significance due to its impacts on biodiversity. It can alter the soil properties of invaded ecosystems and, as a result, affect management outcomes. However, knowledge on the impacts of L. camara on soil properties is scanty, especially in South Africa, despite the pervasive presence of the plant in the country. In this comparative study, the soils underneath L. camara were assessed in order to determine if they had different properties (soil physico-chemical properties, penetration resistance, infiltration, hydraulic conductivity and water repellency) in comparison to the soils in adjacent natural sites in the Eastern Cape, South Africa. Soil samples were collected from the top soil beneath the canopy of both L. camara-invaded and adjacent natural sites in five different locations over three summer months. The soils that were collected from underneath L. camara had a significantly higher total C, total P, gravimetric soil moisture (in November and December) and were repellent, compared to the soils in the adjacent natural sites. Soil penetration resistance was significantly higher in the natural sites than in the L. camara-invaded sites. The soil hydraulic conductivity, soil infiltration rate, soil pH, exchangeable cations and total N showed no significant difference between the invaded and the natural sites. It appears that the soils underneath L. camara have a high total C and total P, soil moisture and are repellent, thus influencing nutrient cycling, potentially making the soil properties underneath it ideal for its own growth. This could contribute to the success of L. camara as an invasive species.
- Full Text:
- Authors: Ruwanza, Sheunesu , Shackleton, Charlie M
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180459 , vital:43391 , xlink:href="https://doi.org/10.1111/wbm.12094"
- Description: Lantana camara L. is an invasive alien shrub of worldwide significance due to its impacts on biodiversity. It can alter the soil properties of invaded ecosystems and, as a result, affect management outcomes. However, knowledge on the impacts of L. camara on soil properties is scanty, especially in South Africa, despite the pervasive presence of the plant in the country. In this comparative study, the soils underneath L. camara were assessed in order to determine if they had different properties (soil physico-chemical properties, penetration resistance, infiltration, hydraulic conductivity and water repellency) in comparison to the soils in adjacent natural sites in the Eastern Cape, South Africa. Soil samples were collected from the top soil beneath the canopy of both L. camara-invaded and adjacent natural sites in five different locations over three summer months. The soils that were collected from underneath L. camara had a significantly higher total C, total P, gravimetric soil moisture (in November and December) and were repellent, compared to the soils in the adjacent natural sites. Soil penetration resistance was significantly higher in the natural sites than in the L. camara-invaded sites. The soil hydraulic conductivity, soil infiltration rate, soil pH, exchangeable cations and total N showed no significant difference between the invaded and the natural sites. It appears that the soils underneath L. camara have a high total C and total P, soil moisture and are repellent, thus influencing nutrient cycling, potentially making the soil properties underneath it ideal for its own growth. This could contribute to the success of L. camara as an invasive species.
- Full Text:
Efficient energy transfer in ethynyl bridged corrole–BODIPY dyads
- Yan, Yu, Wu, Fan, Qin, Jiawei, Xu, Haijun, Shi, Maohu, Zhou, Jingfeng, Mack, John, Fomo, Gertrude, Nyokong, Tebello, Shen, Zhen
- Authors: Yan, Yu , Wu, Fan , Qin, Jiawei , Xu, Haijun , Shi, Maohu , Zhou, Jingfeng , Mack, John , Fomo, Gertrude , Nyokong, Tebello , Shen, Zhen
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240899 , vital:50883 , xlink:href="https://doi.org/10.1039/C6RA12271J"
- Description: A series of new corrole–BODIPY dyads bridged by ethynyl linker moieties have been synthesized in high yields and fully characterized. The direction of energy transfer upon electronic excitation has been explored, and was found to be dependent on the number of corrole rings and their connection position on the BODIPY core. Intense bands in the absorption spectrum cover most of the visible region, which is potentially advantageous for capturing solar energy. Studies on the excitation spectra and lifetimes suggest that the energy transfer efficiency between the BODIPY and corrole moieties reaches almost 85%, which appears to be efficient in the context of energy transfer within the singlet manifold.
- Full Text:
- Authors: Yan, Yu , Wu, Fan , Qin, Jiawei , Xu, Haijun , Shi, Maohu , Zhou, Jingfeng , Mack, John , Fomo, Gertrude , Nyokong, Tebello , Shen, Zhen
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240899 , vital:50883 , xlink:href="https://doi.org/10.1039/C6RA12271J"
- Description: A series of new corrole–BODIPY dyads bridged by ethynyl linker moieties have been synthesized in high yields and fully characterized. The direction of energy transfer upon electronic excitation has been explored, and was found to be dependent on the number of corrole rings and their connection position on the BODIPY core. Intense bands in the absorption spectrum cover most of the visible region, which is potentially advantageous for capturing solar energy. Studies on the excitation spectra and lifetimes suggest that the energy transfer efficiency between the BODIPY and corrole moieties reaches almost 85%, which appears to be efficient in the context of energy transfer within the singlet manifold.
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Electrocatalytic activity of nanocomposites of sulphur doped graphene oxide and nanosized cobalt phthalocyanines
- Shumba, Munyaradzi, Nyokong, Tebello
- Authors: Shumba, Munyaradzi , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188530 , vital:44762 , xlink:href="https://doi.org/10.1002/elan.201600226"
- Description: In this work we explore the electrocatalytic activity of nanocomposites of reduced sulphur doped graphene oxide nanosheets (rSDGONS) and cobalt phthalocyanine (CoPc) or cobalt tetra amino phthalocyanine (CoTAPc) towards hydrogen peroxide. Transmission electron microscopy, scanning electron microscopy, X-ray photon spectroscopy, X-ray diffraction, chronoamperometry, linear scan voltammetry and cyclic voltammetry were used to characterize the nanocomposites. Nanosized CoPc showed superior (in terms of currents) electrocatalytic oxidation and reduction of hydrogen peroxide compared to CoTAPc nanoparticles (CoTAPcNP). The lowest detection limit was obtained for hydrogen peroxide oxidation on electrodes modified with CoPcNP-rSDGONS at 1.49 µM. The same electrode gave a high adsorption equilibrium constant of 1.27×103 mol−1 and a Gibbs free energy of −17.71 kJ/mol, indicative of a spontaneous reaction on the electrode surface.
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- Authors: Shumba, Munyaradzi , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188530 , vital:44762 , xlink:href="https://doi.org/10.1002/elan.201600226"
- Description: In this work we explore the electrocatalytic activity of nanocomposites of reduced sulphur doped graphene oxide nanosheets (rSDGONS) and cobalt phthalocyanine (CoPc) or cobalt tetra amino phthalocyanine (CoTAPc) towards hydrogen peroxide. Transmission electron microscopy, scanning electron microscopy, X-ray photon spectroscopy, X-ray diffraction, chronoamperometry, linear scan voltammetry and cyclic voltammetry were used to characterize the nanocomposites. Nanosized CoPc showed superior (in terms of currents) electrocatalytic oxidation and reduction of hydrogen peroxide compared to CoTAPc nanoparticles (CoTAPcNP). The lowest detection limit was obtained for hydrogen peroxide oxidation on electrodes modified with CoPcNP-rSDGONS at 1.49 µM. The same electrode gave a high adsorption equilibrium constant of 1.27×103 mol−1 and a Gibbs free energy of −17.71 kJ/mol, indicative of a spontaneous reaction on the electrode surface.
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Electrode modification using alkyne manganese phthalocyanine and click chemistry for electrocatalysis
- O'Donoghue, Charles St John Nqwabuko, Fomo, Gertrude, Nyokong, Tebello
- Authors: O'Donoghue, Charles St John Nqwabuko , Fomo, Gertrude , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188541 , vital:44763 , xlink:href="https://doi.org/10.1002/elan.201600379"
- Description: In this work, azidobenzene diazonium salt is grafted onto a glassy carbon electrode (GCE) followed by clicking of manganese tetrahexynyl phthalocyanine for the electrocatalysis of hydrazine. The GCE was first grafted via the in situ diazotization of a diazonium salt, rendering the GCE surface layered with azide groups. From this point, the 1,3-dipolar cycloaddition reaction, catalyzed by a copper catalyst was utilized to ‘click’ the manganese tetrahexynyl phthalocyanine to the surface of the grafted GCE. This new platform was then characterized using cyclic voltammetry (CV), scanning electrochemical microscopy (SECM) and X-ray photoelectron spectroscopy (XPS). Based on the cyclic voltammetry calibration curve of electrocatalysis for hydrazine, the clicked Mn phthalocyanine electrode proved to be an effective sensor with a sensitivity of 27.38 µA mM−1 and the limit of detection (LoD) of 15.4 pM which is a great improvement compared to other reported sensors for this analyte.
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- Authors: O'Donoghue, Charles St John Nqwabuko , Fomo, Gertrude , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188541 , vital:44763 , xlink:href="https://doi.org/10.1002/elan.201600379"
- Description: In this work, azidobenzene diazonium salt is grafted onto a glassy carbon electrode (GCE) followed by clicking of manganese tetrahexynyl phthalocyanine for the electrocatalysis of hydrazine. The GCE was first grafted via the in situ diazotization of a diazonium salt, rendering the GCE surface layered with azide groups. From this point, the 1,3-dipolar cycloaddition reaction, catalyzed by a copper catalyst was utilized to ‘click’ the manganese tetrahexynyl phthalocyanine to the surface of the grafted GCE. This new platform was then characterized using cyclic voltammetry (CV), scanning electrochemical microscopy (SECM) and X-ray photoelectron spectroscopy (XPS). Based on the cyclic voltammetry calibration curve of electrocatalysis for hydrazine, the clicked Mn phthalocyanine electrode proved to be an effective sensor with a sensitivity of 27.38 µA mM−1 and the limit of detection (LoD) of 15.4 pM which is a great improvement compared to other reported sensors for this analyte.
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Electrode modification using nanocomposites of boron or nitrogen doped graphene oxide and cobalt (II) tetra aminophenoxy phthalocyanine nanoparticles
- Shumba, Munyaradzi, Nyokong, Tebello
- Authors: Shumba, Munyaradzi , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188699 , vital:44777 , xlink:href="https://doi.org/10.1016/j.electacta.2016.02.166"
- Description: Reduced graphene oxide nanosheets (rGONS), reduced boron doped graphene oxide nanosheets (rBDGONS) and reduced nitrogen doped graphene oxide nanosheets (rNDGONS) and their composites with cobalt tetra aminophenoxy phthalocyanine nanoparticles (CoTAPhPcNP) were employed towards the detection of hydrogen peroxide. The nanomaterials were characterized by absorption spectroscopy, transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, linear sweep voltammetry and cyclic voltammetry. rNDGONS showed excellent electrooxidation and electroreduction of hydrogen peroxide supported by superior surface coverage values. The inclusion of nanosized Pc significantly lowered the reduction overpotential. CoTAPhPcNP-rNDGONS-GCE gave a sensitivity of 39.30 mA/M, catalytic rate constant of 1 × 103 M−1 s−1 and a detection limit of 8.2 nM. An adsorption equilibrium constant and Gibbs free energy of 1.26 × 103 M−1 and −17.69 kJ mol−1 respectively were observed.
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- Authors: Shumba, Munyaradzi , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188699 , vital:44777 , xlink:href="https://doi.org/10.1016/j.electacta.2016.02.166"
- Description: Reduced graphene oxide nanosheets (rGONS), reduced boron doped graphene oxide nanosheets (rBDGONS) and reduced nitrogen doped graphene oxide nanosheets (rNDGONS) and their composites with cobalt tetra aminophenoxy phthalocyanine nanoparticles (CoTAPhPcNP) were employed towards the detection of hydrogen peroxide. The nanomaterials were characterized by absorption spectroscopy, transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, linear sweep voltammetry and cyclic voltammetry. rNDGONS showed excellent electrooxidation and electroreduction of hydrogen peroxide supported by superior surface coverage values. The inclusion of nanosized Pc significantly lowered the reduction overpotential. CoTAPhPcNP-rNDGONS-GCE gave a sensitivity of 39.30 mA/M, catalytic rate constant of 1 × 103 M−1 s−1 and a detection limit of 8.2 nM. An adsorption equilibrium constant and Gibbs free energy of 1.26 × 103 M−1 and −17.69 kJ mol−1 respectively were observed.
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