Eye of a needle
- Authors: Fick, Cornelia
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:6003 , http://hdl.handle.net/10962/d1021210
- Description: Most of my stories are about interpersonal relationships between the sexes, as well as intrapersonal processes, such as growing old. I have a deep connection to such themes because of my background as a general nurse and midwife; meeting too many abused women in hospitals, and the broader community. Because patterns of abuse tend to become invisible, I use experimental forms of storytelling as well as sharp, ironic and dark humour as a way to make this side of life more visible. My reading has shown me how experimental forms can render seemingly timeless or ageless topics in a fresh, vital way.
- Full Text:
- Authors: Fick, Cornelia
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:6003 , http://hdl.handle.net/10962/d1021210
- Description: Most of my stories are about interpersonal relationships between the sexes, as well as intrapersonal processes, such as growing old. I have a deep connection to such themes because of my background as a general nurse and midwife; meeting too many abused women in hospitals, and the broader community. Because patterns of abuse tend to become invisible, I use experimental forms of storytelling as well as sharp, ironic and dark humour as a way to make this side of life more visible. My reading has shown me how experimental forms can render seemingly timeless or ageless topics in a fresh, vital way.
- Full Text:
Facebook, youth and political action: a comparative study of Zimbabwe and South Africa
- Authors: Mare, Admire
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3553 , http://hdl.handle.net/10962/d1021259
- Description: This comparative multi-sited study examines how, why and when politically engaged youths in distinctive national and social movement contexts use Facebook to facilitate political activism. As part of the research objectives, this study is concerned with investigating how and why youth activists in Zimbabwe and South Africa use the popular corporate social network site for political purposes. The study explores the discursive interactions and micro-politics of participation which plays out on selected Facebook groups and pages. It also examines the extent to which the selected Facebook pages and groups can be considered as alternative spaces for political activism. It also documents and analyses the various kinds of political discourses (described here as digital hidden transcripts) which are circulated by Zimbabwean and South African youth activists on Facebook fan pages and groups. Methodologically, this study adopts a predominantly qualitative research design although it also draws on quantitative data in terms of levels of interaction on Facebook groups and pages. Consequently, this study engages in data triangulation which allows me to make sense of how and why politically engaged youths from a range of six social movements in Zimbabwe and South Africa use Facebook for political action. In terms of data collection techniques, the study deploys social media ethnography (online participant observation), qualitative content analysis and in-depth interviews. Theoretically, this study jettisons the Habermasian theory of public sphere in favour of Fraser’s (1990) concept of the subaltern counter-publics, Scott’s (1985) metaphor of hidden transcripts and some insightful views on popular culture gleaned from African studies. Melding these ideas into a synthesised theoretical frame, this study argues that Facebook fan pages and groups can be conceptualised as parallel discursive arenas where marginalised groups (including politically active youths) have a political life outside the dominant mediated public sphere often in ways that are generally viewed as “irrational” and “non-political” in mainstream Western literature. This study also proposes ways of enriching Fraser’s concept of subaltern counter-publics by incorporating elements from Scott’s metaphor of hidden transcripts in order to analyse the various kinds of political discourses which are circulated on social media. The findings demonstrate that youth activists in Zimbabwe and South Africa are using Facebook to engage in traditional and alternative forms of political participation. Findings show that Facebook in both political contexts is deployed for transmitting and accessing civic and political information, as a conduit for online donations and fundraising, for contacting political decision makers, as a venue of political activism, as an advertising platform for social and political events and as a platform for everyday political talk. It demonstrates that the broader political context shapes and constraints the localised appropriations of Facebook for political purposes in ways that deconstructs some of the postulations of the cyber-optimist and pessimist approaches. The study also found that youth activists in Zimbabwe and South Africa used Facebook in their own unique ways as shaped and dictated by the broader political and mediated opportunity structures. It argues that youth’s engagement with social media platforms for political purposes should be understood in their own terms without necessarily imposing inflexible boundaries on what counts as political participation. Although Facebook like other social media platforms foster avenues for cognitive engagement, discursive participation and political mobilisation, these political practices are not immune to the influences of offline processes. Youth activists in all the six case organisations used Facebook as a complementary and supplementary space for political processes rather than as a standalone platform. The study also argues that compared to South Africa, the political uses of Facebook in Zimbabwe are largely influenced by practices of state surveillance. It also found that whilst youth activists in South Africa are deploying Facebook to supplement traditional methods of political activism, their counterparts in Zimbabwe are using the same technology to circumvent the restricted political and media environment. The findings also indicate that youth activists in both countries are using Facebook as a change agent tool within the broader media ecology which is characterised by the increasing interpenetration of older and newer media platforms. In terms of micro-politics of participation and discursive interactions, this study found that Facebook pages and groups should viewed as a “sites of power” where corporate forces and platform specific code coalesce together fostering “algorithmic” gatekeeping practices and the favouring of paid for content over non-paid for user-generated-content which ultimately affects activists’ visibility and reach within the online media ecology. These gatekeeping practices therefore further complicate claims by cyber-optimists that social media platforms are the sine qua non spaces for symmetrical and democratic participation. This study argues that “subtle forms of control” characterise the much glorified participatory cultures on Facebook in ways that defy optimistic accounts of the role of new media in political change.
- Full Text:
- Authors: Mare, Admire
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3553 , http://hdl.handle.net/10962/d1021259
- Description: This comparative multi-sited study examines how, why and when politically engaged youths in distinctive national and social movement contexts use Facebook to facilitate political activism. As part of the research objectives, this study is concerned with investigating how and why youth activists in Zimbabwe and South Africa use the popular corporate social network site for political purposes. The study explores the discursive interactions and micro-politics of participation which plays out on selected Facebook groups and pages. It also examines the extent to which the selected Facebook pages and groups can be considered as alternative spaces for political activism. It also documents and analyses the various kinds of political discourses (described here as digital hidden transcripts) which are circulated by Zimbabwean and South African youth activists on Facebook fan pages and groups. Methodologically, this study adopts a predominantly qualitative research design although it also draws on quantitative data in terms of levels of interaction on Facebook groups and pages. Consequently, this study engages in data triangulation which allows me to make sense of how and why politically engaged youths from a range of six social movements in Zimbabwe and South Africa use Facebook for political action. In terms of data collection techniques, the study deploys social media ethnography (online participant observation), qualitative content analysis and in-depth interviews. Theoretically, this study jettisons the Habermasian theory of public sphere in favour of Fraser’s (1990) concept of the subaltern counter-publics, Scott’s (1985) metaphor of hidden transcripts and some insightful views on popular culture gleaned from African studies. Melding these ideas into a synthesised theoretical frame, this study argues that Facebook fan pages and groups can be conceptualised as parallel discursive arenas where marginalised groups (including politically active youths) have a political life outside the dominant mediated public sphere often in ways that are generally viewed as “irrational” and “non-political” in mainstream Western literature. This study also proposes ways of enriching Fraser’s concept of subaltern counter-publics by incorporating elements from Scott’s metaphor of hidden transcripts in order to analyse the various kinds of political discourses which are circulated on social media. The findings demonstrate that youth activists in Zimbabwe and South Africa are using Facebook to engage in traditional and alternative forms of political participation. Findings show that Facebook in both political contexts is deployed for transmitting and accessing civic and political information, as a conduit for online donations and fundraising, for contacting political decision makers, as a venue of political activism, as an advertising platform for social and political events and as a platform for everyday political talk. It demonstrates that the broader political context shapes and constraints the localised appropriations of Facebook for political purposes in ways that deconstructs some of the postulations of the cyber-optimist and pessimist approaches. The study also found that youth activists in Zimbabwe and South Africa used Facebook in their own unique ways as shaped and dictated by the broader political and mediated opportunity structures. It argues that youth’s engagement with social media platforms for political purposes should be understood in their own terms without necessarily imposing inflexible boundaries on what counts as political participation. Although Facebook like other social media platforms foster avenues for cognitive engagement, discursive participation and political mobilisation, these political practices are not immune to the influences of offline processes. Youth activists in all the six case organisations used Facebook as a complementary and supplementary space for political processes rather than as a standalone platform. The study also argues that compared to South Africa, the political uses of Facebook in Zimbabwe are largely influenced by practices of state surveillance. It also found that whilst youth activists in South Africa are deploying Facebook to supplement traditional methods of political activism, their counterparts in Zimbabwe are using the same technology to circumvent the restricted political and media environment. The findings also indicate that youth activists in both countries are using Facebook as a change agent tool within the broader media ecology which is characterised by the increasing interpenetration of older and newer media platforms. In terms of micro-politics of participation and discursive interactions, this study found that Facebook pages and groups should viewed as a “sites of power” where corporate forces and platform specific code coalesce together fostering “algorithmic” gatekeeping practices and the favouring of paid for content over non-paid for user-generated-content which ultimately affects activists’ visibility and reach within the online media ecology. These gatekeeping practices therefore further complicate claims by cyber-optimists that social media platforms are the sine qua non spaces for symmetrical and democratic participation. This study argues that “subtle forms of control” characterise the much glorified participatory cultures on Facebook in ways that defy optimistic accounts of the role of new media in political change.
- Full Text:
Fat in a time of slim: the reinscription of race in the framing of fat desirability in post-apartheid South Africa
- Authors: Vincent, Louise
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141591 , vital:37988 , DOI: 10.1177/1363460716640730
- Description: This article critically examines the way in which the reported sexual desire of black African men for fat women is contained and managed in South African media representations of fat. While sexual desire for fat women represents a potential challenge to the dominant framing of fat as diseased/dysfunctional/disgusting, the article shows how the reduction of this desire to one of two (racialized) ‘explanations’ – either evidence of racial primitivism or a (black male) strategy to avoid infection with HIV – emasculates the potentially powerful oppositional framing of fat as sexy. It is a mark of the dominant frame’s influence that it is capable of co-opting oppositional frames and recasting them in its own image. From the point of view of critiques of the fat-as-disease orthodoxy, the claim to the existence of an alternative norm of fat as sexually desirable in ‘black culture’ emerges as a problematic oppositional frame – saturated with raced assumptions in the way in which it is reported. The counter framing of the (black) fat body as sexually desirable is given column space to be derided and dismissed as an instance of deviant black sexuality, as a mistaken belief in need of ‘correction’, or it is subsumed under a medicalized frame as a strategy for the avoidance of disease rather than an expression of genuine sexual desire.
- Full Text:
- Authors: Vincent, Louise
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141591 , vital:37988 , DOI: 10.1177/1363460716640730
- Description: This article critically examines the way in which the reported sexual desire of black African men for fat women is contained and managed in South African media representations of fat. While sexual desire for fat women represents a potential challenge to the dominant framing of fat as diseased/dysfunctional/disgusting, the article shows how the reduction of this desire to one of two (racialized) ‘explanations’ – either evidence of racial primitivism or a (black male) strategy to avoid infection with HIV – emasculates the potentially powerful oppositional framing of fat as sexy. It is a mark of the dominant frame’s influence that it is capable of co-opting oppositional frames and recasting them in its own image. From the point of view of critiques of the fat-as-disease orthodoxy, the claim to the existence of an alternative norm of fat as sexually desirable in ‘black culture’ emerges as a problematic oppositional frame – saturated with raced assumptions in the way in which it is reported. The counter framing of the (black) fat body as sexually desirable is given column space to be derided and dismissed as an instance of deviant black sexuality, as a mistaken belief in need of ‘correction’, or it is subsumed under a medicalized frame as a strategy for the avoidance of disease rather than an expression of genuine sexual desire.
- Full Text:
Festival fringe production and the long tail
- Authors: Snowball, Jeanette D
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68855 , vital:29332 , http://www.econrsa.org/node/1170
- Description: Publisher version , In the past 15 years, there has been a worldwide proliferation of arts festivals, including so-called "fringe" festivals, which encouraged more experimental and avant-garde productions. While fringe festival productions had the potential to generate significant income for producers, their aims were primarily related to artistic innovation and it is well known that putting on a fringe show is highly unlikely to provide financial gain for most producers. This is what is referred to in statistics and marketing as a "long tail" distribution, in which a minority of producers in a particular market earn the vast majority of industry income. However, for individual producers of live theatre, such a distribution represents high risks and potentially large financial losses. This article uses producer data from two different fringe festivals in South Africa to explore determinants of ticket sales and box-office income. Included in the analysis is a consideration of the impact of genre and pricing strategies on the probability (Logit model) of shows being in the top 10%, 30% and 50% of best-selling and earning productions. Results support the long tail hypothesis.
- Full Text:
- Authors: Snowball, Jeanette D
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68855 , vital:29332 , http://www.econrsa.org/node/1170
- Description: Publisher version , In the past 15 years, there has been a worldwide proliferation of arts festivals, including so-called "fringe" festivals, which encouraged more experimental and avant-garde productions. While fringe festival productions had the potential to generate significant income for producers, their aims were primarily related to artistic innovation and it is well known that putting on a fringe show is highly unlikely to provide financial gain for most producers. This is what is referred to in statistics and marketing as a "long tail" distribution, in which a minority of producers in a particular market earn the vast majority of industry income. However, for individual producers of live theatre, such a distribution represents high risks and potentially large financial losses. This article uses producer data from two different fringe festivals in South Africa to explore determinants of ticket sales and box-office income. Included in the analysis is a consideration of the impact of genre and pricing strategies on the probability (Logit model) of shows being in the top 10%, 30% and 50% of best-selling and earning productions. Results support the long tail hypothesis.
- Full Text:
Field evaluation of the use of select entomopathogenic fungal isolates as microbial control agents of the soil-dwelling life stages of a key South African citrus pest, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae)
- Authors: Coombes, Candice Anne
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/507 , vital:19965
- Description: The control of false codling moth (FCM), Thaumatotibia leucotreta (Meyrick, 1912) (Lepidoptera: Tortricidae), in citrus orchards is strongly reliant on the use of integrated pest management as key export markets impose stringent chemical restrictions on exported fruit and have a strict no entry policy towards this phytosanitary pest. Most current, registered control methods target the above-ground life stages of FCM, not the soil-dwelling life stages. As such, entomopathogenic fungi which are ubiquitous, percutaneously infective soil-borne microbes that have been used successfully as control agents worldwide, present ideal candidates as additional control agents. Following an initial identification of 62 fungal entomopathogens isolated from soil collected from citrus orchards in the Eastern Cape Province, South Africa, further laboratory research has highlighted three isolates as having the greatest control potential against FCM subterranean life stages: Metarhizium anisopliae G 11 3 L6 (Ma1), M. anisopliae FCM Ar 23 B3 (Ma2) and Beauveria bassiana G Ar 17 B3 (Bb1). These isolates are capable of causing above 80% laboratory-induced mycosis of FCM fifth instars. Whether this level of efficacy was obtainable under sub-optimal and fluctuating field conditions was unknown. Thus, this thesis aimed to address the following issues with regards to the three most laboratory-virulent fungal isolates: field efficacy, field persistence, optimal application rate, application timing, environmental dependency, compatibility with fungicides and the use of different wetting agents to promote field efficacy. Following fungal application to one hectare treatment blocks in the field, FCM infestation within fruit was reduced by 28.3% to 81.7%. Isolate Bb1 performed best under moderate to high soil moisture whilst Ma2 was more effective under low soil moisture conditions. All isolates, with the exception of Ma2 at one site, were recorded in the soil five months post-application. None of the wetting agents tested were found to be highly toxic to fungal germination and similar physical suspension characteristics were observed. Fungicide toxicity varied amongst isolates and test conditions. However, only Dithane (a.i. mancozeb) was considered incompatible with isolate Ma2. The implication of these results and the way forward is discussed. This study is the first report of the field efficacy of three laboratory-virulent fungal isolates applied to the soil of conventional citrus orchards against FCM soil-dwelling life stages. As such, it provides a foundation on which future research can build to ensure the development and commercialisation of a cost-effective and consistently reliable product.
- Full Text:
- Authors: Coombes, Candice Anne
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/507 , vital:19965
- Description: The control of false codling moth (FCM), Thaumatotibia leucotreta (Meyrick, 1912) (Lepidoptera: Tortricidae), in citrus orchards is strongly reliant on the use of integrated pest management as key export markets impose stringent chemical restrictions on exported fruit and have a strict no entry policy towards this phytosanitary pest. Most current, registered control methods target the above-ground life stages of FCM, not the soil-dwelling life stages. As such, entomopathogenic fungi which are ubiquitous, percutaneously infective soil-borne microbes that have been used successfully as control agents worldwide, present ideal candidates as additional control agents. Following an initial identification of 62 fungal entomopathogens isolated from soil collected from citrus orchards in the Eastern Cape Province, South Africa, further laboratory research has highlighted three isolates as having the greatest control potential against FCM subterranean life stages: Metarhizium anisopliae G 11 3 L6 (Ma1), M. anisopliae FCM Ar 23 B3 (Ma2) and Beauveria bassiana G Ar 17 B3 (Bb1). These isolates are capable of causing above 80% laboratory-induced mycosis of FCM fifth instars. Whether this level of efficacy was obtainable under sub-optimal and fluctuating field conditions was unknown. Thus, this thesis aimed to address the following issues with regards to the three most laboratory-virulent fungal isolates: field efficacy, field persistence, optimal application rate, application timing, environmental dependency, compatibility with fungicides and the use of different wetting agents to promote field efficacy. Following fungal application to one hectare treatment blocks in the field, FCM infestation within fruit was reduced by 28.3% to 81.7%. Isolate Bb1 performed best under moderate to high soil moisture whilst Ma2 was more effective under low soil moisture conditions. All isolates, with the exception of Ma2 at one site, were recorded in the soil five months post-application. None of the wetting agents tested were found to be highly toxic to fungal germination and similar physical suspension characteristics were observed. Fungicide toxicity varied amongst isolates and test conditions. However, only Dithane (a.i. mancozeb) was considered incompatible with isolate Ma2. The implication of these results and the way forward is discussed. This study is the first report of the field efficacy of three laboratory-virulent fungal isolates applied to the soil of conventional citrus orchards against FCM soil-dwelling life stages. As such, it provides a foundation on which future research can build to ensure the development and commercialisation of a cost-effective and consistently reliable product.
- Full Text:
Financial characteristics of the nonprofit organisation: theory and evidence for the assessment of the financial condition of South African public universities
- Authors: Bunting, Mark Bevan
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:923 , http://hdl.handle.net/10962/d1021298 , http://orcid.org/0000-0002-3392-554X
- Description: In this thesis, an analytical framework is developed for the assessment of the financial condition of South African public universities. Foundational constructs of nonprofit economics are applied in the consideration of financial theories of nonprofit organisations in general, and public universities in particular. From this review, a number of hypotheses are developed. Each of these specifies a positive or negative association between a university's financial condition and a particular dimension of its assets, liabilities, equity, revenues, expenses and surplus. From the nonprofit financial analysis literature, ratios and indicators relevant to these hypotheses are selected. Audited data from the annual financial statements of the universities for the seven year period 2007 to 2013 are substantially transformed in mitigation of failures in accounting, auditing and accountability. The adjusted accounting numbers are used to calculate the financial indicators applicable to each university. Exploratory factor analysis is implemented to categorise and organise this large indicator set on the basis of identified associations with a smaller number of factors. It is found that the financial condition of South African public universities is defined by two broad financial characteristics, capital and revenue. Assessment of the capital dimension is informed by a focus on institutional equity, with particular emphasis on expendable equity and its proportionate relationships with surplus, total capital, and total expenses. The revenue dimension is appropriately evaluated in the context of a comparative and interactive consideration of the three main components of South African public university revenue, as well as the proportionate relationship between non-staff operating expenses and total expenses. The framework displays considerable levels of stability and consistency over the seven year review period, and its constructs are, in addition, robust to the application of multiple alternative confirmatory tests involving financial data that are independent of the factor solutions. The financial condition assessment framework developed in this thesis offers a contribution to a broader discourse in nonprofit finance and accounting, with a focus on public university finances.
- Full Text:
- Authors: Bunting, Mark Bevan
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:923 , http://hdl.handle.net/10962/d1021298 , http://orcid.org/0000-0002-3392-554X
- Description: In this thesis, an analytical framework is developed for the assessment of the financial condition of South African public universities. Foundational constructs of nonprofit economics are applied in the consideration of financial theories of nonprofit organisations in general, and public universities in particular. From this review, a number of hypotheses are developed. Each of these specifies a positive or negative association between a university's financial condition and a particular dimension of its assets, liabilities, equity, revenues, expenses and surplus. From the nonprofit financial analysis literature, ratios and indicators relevant to these hypotheses are selected. Audited data from the annual financial statements of the universities for the seven year period 2007 to 2013 are substantially transformed in mitigation of failures in accounting, auditing and accountability. The adjusted accounting numbers are used to calculate the financial indicators applicable to each university. Exploratory factor analysis is implemented to categorise and organise this large indicator set on the basis of identified associations with a smaller number of factors. It is found that the financial condition of South African public universities is defined by two broad financial characteristics, capital and revenue. Assessment of the capital dimension is informed by a focus on institutional equity, with particular emphasis on expendable equity and its proportionate relationships with surplus, total capital, and total expenses. The revenue dimension is appropriately evaluated in the context of a comparative and interactive consideration of the three main components of South African public university revenue, as well as the proportionate relationship between non-staff operating expenses and total expenses. The framework displays considerable levels of stability and consistency over the seven year review period, and its constructs are, in addition, robust to the application of multiple alternative confirmatory tests involving financial data that are independent of the factor solutions. The financial condition assessment framework developed in this thesis offers a contribution to a broader discourse in nonprofit finance and accounting, with a focus on public university finances.
- Full Text:
Fluorescence behavior of nanoconjugates of graphene quantum dots and zinc phthalocyanines
- Achadu, Ojodomo John, Uddin, Imran, Nyokong, Tebello
- Authors: Achadu, Ojodomo John , Uddin, Imran , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188777 , vital:44784 , xlink:href="https://doi.org/10.1016/j.jphotochem.2015.11.006"
- Description: Graphene quantum dots (GQDs) and zinc phthalocyanines interactions in different modes (covalent and non-covalent) are reported in this study. GQDs were covalently attached to the following complexes: zinc tetraamino phthalocyanine (ZnTAPc) via amide coupling, zinc tetracarboxyphenoxy Pc (ZnTCPPc) (π–π interaction) and cationic zinc tetrapyridiloxy Pc (ZnTmPyPc) (ionic interaction). GQDs fluorescence was quenched in the presence of the ZnPc derivatives. The nanoensembles of GQDs–ZnPcs showed stimulated emissions of the ZnPcs. The suggested quenching mechanism is through Förster resonance energy transfer (FRET). These novel nanoensembles hold promise for various optical and luminescence based applications.
- Full Text:
- Authors: Achadu, Ojodomo John , Uddin, Imran , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188777 , vital:44784 , xlink:href="https://doi.org/10.1016/j.jphotochem.2015.11.006"
- Description: Graphene quantum dots (GQDs) and zinc phthalocyanines interactions in different modes (covalent and non-covalent) are reported in this study. GQDs were covalently attached to the following complexes: zinc tetraamino phthalocyanine (ZnTAPc) via amide coupling, zinc tetracarboxyphenoxy Pc (ZnTCPPc) (π–π interaction) and cationic zinc tetrapyridiloxy Pc (ZnTmPyPc) (ionic interaction). GQDs fluorescence was quenched in the presence of the ZnPc derivatives. The nanoensembles of GQDs–ZnPcs showed stimulated emissions of the ZnPcs. The suggested quenching mechanism is through Förster resonance energy transfer (FRET). These novel nanoensembles hold promise for various optical and luminescence based applications.
- Full Text:
Fluorescence properties of alloyed ZnSeS quantum dots overcoated with ZnTe and ZnTe/ZnS shells
- Adegoke, Oluwasesan, Mashazi, Philani N, Nyokong, Tebello, Forbes, Patricia B C
- Authors: Adegoke, Oluwasesan , Mashazi, Philani N , Nyokong, Tebello , Forbes, Patricia B C
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240754 , vital:50868 , xlink:href="https://doi.org/10.1016/j.optmat.2016.02.024"
- Description: Fluorescent alloyed ternary ZnSeS quantum dots (QDs) have been synthesized via the pyrolysis of organometallic precursors. The effects of passivation of ZnTe and ZnTe/ZnS shells on the optical properties of the ternary alloyed ZnSeS core have been studied. A ligand exchange reaction using L-cysteine as a capping ligand was used to obtain water-soluble nanocrystals. The nanocrystals were each characterized by UV/vis absorption and fluorescence spectroscopy, transmission electron microscopy, X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). The photoluminescence (PL) quantum yield (QY) of alloyed ZnSeS QDs was 14% and this value increased to 27% when ZnTe was overcoated around the surface but further coating with a ZnS shell decreased the PL QY slightly to 24%. This implies that ZnTe shell suppressed non-radiative recombination exciton states in the alloyed core while further layering with a ZnS shell offered no further improvement in suppressing the defect states. XPS analysis confirmed the presence of the first shell layering but showed a weakened intensity signal of S (2p) and Se (3d) for the ZnSeS/ZnTe/ZnS QDs. Our work demonstrates for the first time that shell passivation of alloyed Zn-based QDs can offer improved optical properties. We hope the optical information presented in this work will be useful in the selection of alloyed Zn-based QDs appropriate for the intended application.
- Full Text:
- Authors: Adegoke, Oluwasesan , Mashazi, Philani N , Nyokong, Tebello , Forbes, Patricia B C
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240754 , vital:50868 , xlink:href="https://doi.org/10.1016/j.optmat.2016.02.024"
- Description: Fluorescent alloyed ternary ZnSeS quantum dots (QDs) have been synthesized via the pyrolysis of organometallic precursors. The effects of passivation of ZnTe and ZnTe/ZnS shells on the optical properties of the ternary alloyed ZnSeS core have been studied. A ligand exchange reaction using L-cysteine as a capping ligand was used to obtain water-soluble nanocrystals. The nanocrystals were each characterized by UV/vis absorption and fluorescence spectroscopy, transmission electron microscopy, X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). The photoluminescence (PL) quantum yield (QY) of alloyed ZnSeS QDs was 14% and this value increased to 27% when ZnTe was overcoated around the surface but further coating with a ZnS shell decreased the PL QY slightly to 24%. This implies that ZnTe shell suppressed non-radiative recombination exciton states in the alloyed core while further layering with a ZnS shell offered no further improvement in suppressing the defect states. XPS analysis confirmed the presence of the first shell layering but showed a weakened intensity signal of S (2p) and Se (3d) for the ZnSeS/ZnTe/ZnS QDs. Our work demonstrates for the first time that shell passivation of alloyed Zn-based QDs can offer improved optical properties. We hope the optical information presented in this work will be useful in the selection of alloyed Zn-based QDs appropriate for the intended application.
- Full Text:
Four husbands for Ma Lindi: an exploration of the interaction between theatrical performance, gender, and sexuality in a South African urban context
- Authors: Vaughan, Clara
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/4610 , vital:20700
- Description: The thesis investigates the possibilities and limitations of theatre-making in providing a space for young people to collectively create, share, and interrogate understandings about sex, sexuality and gender. I use as a case study a theatremaking process I facilitated with a group of first year drama students at the Market Theatre Laboratory, in which we created a play called Four Husbands for Ma Lindi. The research analyses how this process interacted with the identities-in-becoming of the individual creators, and their engagement with the world, through a methodology that views them as experts on their own lives. There are three main arguments that I put forward in this thesis: the first is based on the experiences of healing, increased confidence and self-knowledge described by the participants as a result of sharing their personal stories in making the play. I argue that exploring autobiographical narratives through the aesthetic of theatre creates a group story that re-situates the narratives, the tellers and the witnesses in ways that can be productive for sexual and personal wellbeing, while also providing a counter-narrative that problematises the idea that sharing personal stories is always and necessarily a positive act. My second argument is that theatre-making, because it is an embodied performance pedagogy, is a constructive site in which to interrogate, deconstruct and subvert embedded gender norms and values, which are learnt and reiterated in the body. My third argument considers the relationship between theatre and change that is suggested by the findings of the research. In an analysis of the responses of the participants, I contend that theatre's potential for creating change in the socio-cultural domain lies in its ability to carve out spaces for improvisation, rather than to serve as a rehearsal for the real world. This is the position from which I then consider my ethics of practice and the role and responsibility of the facilitator in processes that view theatre-making as a critical performance pedagogy.
- Full Text:
- Authors: Vaughan, Clara
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/4610 , vital:20700
- Description: The thesis investigates the possibilities and limitations of theatre-making in providing a space for young people to collectively create, share, and interrogate understandings about sex, sexuality and gender. I use as a case study a theatremaking process I facilitated with a group of first year drama students at the Market Theatre Laboratory, in which we created a play called Four Husbands for Ma Lindi. The research analyses how this process interacted with the identities-in-becoming of the individual creators, and their engagement with the world, through a methodology that views them as experts on their own lives. There are three main arguments that I put forward in this thesis: the first is based on the experiences of healing, increased confidence and self-knowledge described by the participants as a result of sharing their personal stories in making the play. I argue that exploring autobiographical narratives through the aesthetic of theatre creates a group story that re-situates the narratives, the tellers and the witnesses in ways that can be productive for sexual and personal wellbeing, while also providing a counter-narrative that problematises the idea that sharing personal stories is always and necessarily a positive act. My second argument is that theatre-making, because it is an embodied performance pedagogy, is a constructive site in which to interrogate, deconstruct and subvert embedded gender norms and values, which are learnt and reiterated in the body. My third argument considers the relationship between theatre and change that is suggested by the findings of the research. In an analysis of the responses of the participants, I contend that theatre's potential for creating change in the socio-cultural domain lies in its ability to carve out spaces for improvisation, rather than to serve as a rehearsal for the real world. This is the position from which I then consider my ethics of practice and the role and responsibility of the facilitator in processes that view theatre-making as a critical performance pedagogy.
- Full Text:
FRAME: frame routing and manipulation engine
- Authors: Pennefather, Sean Niel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3608 , vital:20529
- Description: This research reports on the design and implementation of FRAME: an embedded hardware network processing platform designed to perform network frame manipulation and monitoring. This is possible at line speeds compliant with the IEEE 802.3 Ethernet standard. The system provides frame manipulation functionality to aid in the development and implementation of network testing environments. Platform cost and ease of use are both considered during design resulting in fabrication of hardware and the development of Link, a Domain Specific Language used to create custom applications that are compatible with the platform. Functionality of the resulting platform is shown through conformance testing of designed modules and application examples. Throughput testing showed that the peak throughput achievable by the platform is limited to 86.4 Mbit/s, comparable to commodity 100 Mbit hardware and the total cost of the prototype platform ranged between $220 and $254.
- Full Text:
- Authors: Pennefather, Sean Niel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3608 , vital:20529
- Description: This research reports on the design and implementation of FRAME: an embedded hardware network processing platform designed to perform network frame manipulation and monitoring. This is possible at line speeds compliant with the IEEE 802.3 Ethernet standard. The system provides frame manipulation functionality to aid in the development and implementation of network testing environments. Platform cost and ease of use are both considered during design resulting in fabrication of hardware and the development of Link, a Domain Specific Language used to create custom applications that are compatible with the platform. Functionality of the resulting platform is shown through conformance testing of designed modules and application examples. Throughput testing showed that the peak throughput achievable by the platform is limited to 86.4 Mbit/s, comparable to commodity 100 Mbit hardware and the total cost of the prototype platform ranged between $220 and $254.
- Full Text:
From global to regional and back again: common climate stressors of marine ecosystems relevant for adaptation across five ocean warming hotspots
- Popova, Ekaterina, Yool, Andrew, Byfield, Valborg, Cochrane, Kevern, Coward, Andrew C, Salim, Shyam S, Gasalla, Maria A, Henson, S.A, Hobday, Alistair J, Pecl, Gretta T, Sauer, Warwick H H, Roberts, Michael J
- Authors: Popova, Ekaterina , Yool, Andrew , Byfield, Valborg , Cochrane, Kevern , Coward, Andrew C , Salim, Shyam S , Gasalla, Maria A , Henson, S.A , Hobday, Alistair J , Pecl, Gretta T , Sauer, Warwick H H , Roberts, Michael J
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124514 , vital:35623 , https://doi.10.1111/gcb.13247
- Description: Ocean warming ‘hotspots’ are regions characterized by above-average temperature increases over recent years, for which there are significant consequences for both living marine resources and the societies that depend on them. As such, they represent early warning systems for understanding the impacts of marine climate change, and test-beds for developing adaptation options for coping with those impacts. Here, we examine five hotspots off the coasts of eastern Australia, South Africa, Madagascar, India and Brazil. These particular hotspots have underpinned a large international partnership that is working towards improving community adaptation by characterizing, assessing and projecting the likely future of coastal-marine food resources through the provision and sharing of knowledge. To inform this effort, we employ a high-resolution global ocean model forced by Representative Concentration Pathway 8.5 and simulated to year 2099. In addition to the sea surface temperature, we analyse projected stratification, nutrient supply, primary production, anthropogenic CO2-driven ocean acidification, deoxygenation and ocean circulation. Our simulation finds that the temperature-defined hotspots studied here will continue to experience warming but, with the exception of eastern Australia, may not remain the fastest warming ocean areas over the next century as the strongest warming is projected to occur in the subpolar and polar areas of the Northern Hemisphere. Additionally, we find that recent rapid change in SST is not necessarily an indicator that these areas are also hotspots of the other climatic stressors examined. However, a consistent facet of the hotspots studied here is that they are all strongly influenced by ocean circulation, which has already shown changes in the recent past and is projected to undergo further strong change into the future. In addition to the fast warming, change in local ocean circulation represents a distinct feature of present and future climate change impacting marine ecosystems in these areas.
- Full Text:
- Authors: Popova, Ekaterina , Yool, Andrew , Byfield, Valborg , Cochrane, Kevern , Coward, Andrew C , Salim, Shyam S , Gasalla, Maria A , Henson, S.A , Hobday, Alistair J , Pecl, Gretta T , Sauer, Warwick H H , Roberts, Michael J
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124514 , vital:35623 , https://doi.10.1111/gcb.13247
- Description: Ocean warming ‘hotspots’ are regions characterized by above-average temperature increases over recent years, for which there are significant consequences for both living marine resources and the societies that depend on them. As such, they represent early warning systems for understanding the impacts of marine climate change, and test-beds for developing adaptation options for coping with those impacts. Here, we examine five hotspots off the coasts of eastern Australia, South Africa, Madagascar, India and Brazil. These particular hotspots have underpinned a large international partnership that is working towards improving community adaptation by characterizing, assessing and projecting the likely future of coastal-marine food resources through the provision and sharing of knowledge. To inform this effort, we employ a high-resolution global ocean model forced by Representative Concentration Pathway 8.5 and simulated to year 2099. In addition to the sea surface temperature, we analyse projected stratification, nutrient supply, primary production, anthropogenic CO2-driven ocean acidification, deoxygenation and ocean circulation. Our simulation finds that the temperature-defined hotspots studied here will continue to experience warming but, with the exception of eastern Australia, may not remain the fastest warming ocean areas over the next century as the strongest warming is projected to occur in the subpolar and polar areas of the Northern Hemisphere. Additionally, we find that recent rapid change in SST is not necessarily an indicator that these areas are also hotspots of the other climatic stressors examined. However, a consistent facet of the hotspots studied here is that they are all strongly influenced by ocean circulation, which has already shown changes in the recent past and is projected to undergo further strong change into the future. In addition to the fast warming, change in local ocean circulation represents a distinct feature of present and future climate change impacting marine ecosystems in these areas.
- Full Text:
Fundisa for Change teacher professional development programme
- Authors: Tshiningayamwe, Sirkka A
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432999 , vital:72922 , xlink:href="https://eeasa.org.za/wp-content/uploads/2017/05/EEASA-Bullitin-vol-43.pdf"
- Description: Environment and sustainability content has been integrated into the South African curricula documents, including the past ones. This integration was followed by initiatives which aimed at supporting teachers to implement environmental knowledge and action in the curriculum. For example, the Learning for Sustainability project was piloted in Gauteng and Mpumalanga province between the year 1997 and 2000. The project followed a three pillar approach of integrating environmental education in the curriculum: teacher development, curriculum development and materials development. As part of the project, a spiral model approach to teacher professional development was introduced.
- Full Text:
- Authors: Tshiningayamwe, Sirkka A
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432999 , vital:72922 , xlink:href="https://eeasa.org.za/wp-content/uploads/2017/05/EEASA-Bullitin-vol-43.pdf"
- Description: Environment and sustainability content has been integrated into the South African curricula documents, including the past ones. This integration was followed by initiatives which aimed at supporting teachers to implement environmental knowledge and action in the curriculum. For example, the Learning for Sustainability project was piloted in Gauteng and Mpumalanga province between the year 1997 and 2000. The project followed a three pillar approach of integrating environmental education in the curriculum: teacher development, curriculum development and materials development. As part of the project, a spiral model approach to teacher professional development was introduced.
- Full Text:
Fusing fact and fiction: biography and autobiography in the novels of Virginia Woolf
- Authors: White, Joshua Craig
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/4005 , vital:20580
- Description: Virginia Woolf was noted for a preoccupation with the genre of life-writing throughout her career. Her aims when it came to reshaping the nature of biographical and autobiographical literature were numerous. She veered away from the aggrandising and patriarchal methods with which Victorian biographers tended to depict their subjects. She increased the focus on women in life-writing, examining and subverting traditionally prescribed gender roles prevalent in both her society and the literature that reflected it, and advocating a balance between male and female patterns of thinking. She also devised a method of incorporating both basic biographical fact and aspects of fiction into life-writing in order to approach a more truthful depiction of a subject’s personality or character. This method is linked to the aforementioned balance of gendered thought patterns, since Woolf often aligns factuality with male thinking and the contrasting qualities of fiction, such as intuition, ambivalence and perspicacity, with female thinking. This thesis examines three novels which demonstrate Woolf’s constant preoccupation with combining fact and fiction in order to capture the essence of personality. In her debut novel, The Voyage Out, she presents Rachel Vinrace, who must achieve a balance of male-oriented fact with female-oriented insight in order to fashion a sufficient identity for herself and to identify others in a selective and judicious manner, thus being simultaneously autobiographical and biographical. In Orlando, Woolf explicitly subverts the traditional Victorian biography by depicting Vita Sackville-West as a man who transforms into a woman and remains living for over 400 years. In presenting such a character, Woolf posits that personality consists of and is influenced by myriad aspects of a person’s life that cannot be documented in the restrictive manner employed by Victorian biographers. Orlando’s essence being obfuscated by manifold “selves” attests to Woolf problematizing attempts to attain such an essence. The same challenge is particularly important in her autobiographical novel, To the Lighthouse, in which she transposes the traumas of her own life into a fictitious narrative in order to achieve catharsis for her and her readers, and to present the difficulty in capturing the essence of character. The conclusion that Woolf eventually posits is that personality cannot be reduced to an essence, but rather that it consists of idiosyncrasies that are various, intertwining, and capricious.
- Full Text:
- Authors: White, Joshua Craig
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/4005 , vital:20580
- Description: Virginia Woolf was noted for a preoccupation with the genre of life-writing throughout her career. Her aims when it came to reshaping the nature of biographical and autobiographical literature were numerous. She veered away from the aggrandising and patriarchal methods with which Victorian biographers tended to depict their subjects. She increased the focus on women in life-writing, examining and subverting traditionally prescribed gender roles prevalent in both her society and the literature that reflected it, and advocating a balance between male and female patterns of thinking. She also devised a method of incorporating both basic biographical fact and aspects of fiction into life-writing in order to approach a more truthful depiction of a subject’s personality or character. This method is linked to the aforementioned balance of gendered thought patterns, since Woolf often aligns factuality with male thinking and the contrasting qualities of fiction, such as intuition, ambivalence and perspicacity, with female thinking. This thesis examines three novels which demonstrate Woolf’s constant preoccupation with combining fact and fiction in order to capture the essence of personality. In her debut novel, The Voyage Out, she presents Rachel Vinrace, who must achieve a balance of male-oriented fact with female-oriented insight in order to fashion a sufficient identity for herself and to identify others in a selective and judicious manner, thus being simultaneously autobiographical and biographical. In Orlando, Woolf explicitly subverts the traditional Victorian biography by depicting Vita Sackville-West as a man who transforms into a woman and remains living for over 400 years. In presenting such a character, Woolf posits that personality consists of and is influenced by myriad aspects of a person’s life that cannot be documented in the restrictive manner employed by Victorian biographers. Orlando’s essence being obfuscated by manifold “selves” attests to Woolf problematizing attempts to attain such an essence. The same challenge is particularly important in her autobiographical novel, To the Lighthouse, in which she transposes the traumas of her own life into a fictitious narrative in order to achieve catharsis for her and her readers, and to present the difficulty in capturing the essence of character. The conclusion that Woolf eventually posits is that personality cannot be reduced to an essence, but rather that it consists of idiosyncrasies that are various, intertwining, and capricious.
- Full Text:
Generation of New Ecotoxicity Data for Salts Using Indigenous South African Freshwater Macroinvertebrate: Updating the National Salts Toxicity Database
- Mensah, Paul K, Mgaba, Ntombekhaya, Griffin, Neil J, Odume, Oghenekaro N, Palmer, Carolyn G
- Authors: Mensah, Paul K , Mgaba, Ntombekhaya , Griffin, Neil J , Odume, Oghenekaro N , Palmer, Carolyn G
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/437854 , vital:73417 , ISBN 978-1-4312-0747-3 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/KV%20353.pdf
- Description: Scherman and Palmer (2013) reviewed the historical and current trends of Environmental Water Quality (EWQ) in South Africa. Based on the review, they identified research gaps for which they proposed a co-ordinated set of projects that need to be commissioned and executed to fill these gaps. These co-ordinated set of projects include update of TEACHA (Tool for Ecological Aquatic Chemical Habitat Assessment); update of the national salt toxicity database; integration of Resource Directed Measures (RDM) components (ie Ecological Reserve, Re-source Quality Objectives (RQOs) and Classification); integrating water quality and quantity; evaluation of the RDM participatory process based on research and current understandings of complex social-ecological systems and ecosystem services; and integrating RDM and SDC (Source Direct Control) to ensure coherent link between the two. The overarching aim of the above set of projects is to support implementa-tion of the National Water Resource Strategy 2 (NWRS2). Therefore, the main objective of this project to contribute to addressing the second research gap listed above (ie updating the national salt toxicity data-base). Noting that the database contains only data on single salts with nothing on salt mixtures, the project also generated binary salt mixtures data for the database, in addition to generating data for single salts.
- Full Text:
- Authors: Mensah, Paul K , Mgaba, Ntombekhaya , Griffin, Neil J , Odume, Oghenekaro N , Palmer, Carolyn G
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/437854 , vital:73417 , ISBN 978-1-4312-0747-3 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/KV%20353.pdf
- Description: Scherman and Palmer (2013) reviewed the historical and current trends of Environmental Water Quality (EWQ) in South Africa. Based on the review, they identified research gaps for which they proposed a co-ordinated set of projects that need to be commissioned and executed to fill these gaps. These co-ordinated set of projects include update of TEACHA (Tool for Ecological Aquatic Chemical Habitat Assessment); update of the national salt toxicity database; integration of Resource Directed Measures (RDM) components (ie Ecological Reserve, Re-source Quality Objectives (RQOs) and Classification); integrating water quality and quantity; evaluation of the RDM participatory process based on research and current understandings of complex social-ecological systems and ecosystem services; and integrating RDM and SDC (Source Direct Control) to ensure coherent link between the two. The overarching aim of the above set of projects is to support implementa-tion of the National Water Resource Strategy 2 (NWRS2). Therefore, the main objective of this project to contribute to addressing the second research gap listed above (ie updating the national salt toxicity data-base). Noting that the database contains only data on single salts with nothing on salt mixtures, the project also generated binary salt mixtures data for the database, in addition to generating data for single salts.
- Full Text:
Genetic and biological characterisation of a novel South African Cydia pomonella granulovirus (CpGV-SA) isolate
- Motsoeneng, Boitumelo Madika
- Authors: Motsoeneng, Boitumelo Madika
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:20503 , http://hdl.handle.net/10962/d1021266
- Description: The codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is the primary pest of pome fruit cultivated worldwide. The control of this insect pest has been dependent on the frequent use of broad-spectrum chemical pesticides, which has led to the development of resistance in pest populations and negative effects on human health and the environment. The Betabaculovirus of C. pomonella has successfully been applied as a biological control agent in integrated pest management (IPM) programmes for the suppression of pest populations worldwide. Previously, all Cydia pomonella granulovirus (CpGV) biopesticides were based on a Mexican isolate (CpGV-M) and although these products are highly efficient at controlling C. pomonella, resistance cases have been reported across Europe. The identification of novel CpGV isolates as additional or alternative control agents to manage resistance is therefore necessary. This study aimed to genetically and biologically characterise a novel South African C. pomonella granulovirus isolate and to test its virulence against neonate larvae. Based on the morphology of the occlusion bodies observed using transmission electron microscopy, granuloviruses were recovered from diseased and dead larvae collected from an orchard in South Africa where no virus applications had been made. DNA was extracted and the identification of the isolated granulovirus was achieved through the PCR amplification and sequencing of the lef-8, lef-9, granulin and egt genes. Submission of the gene sequences to BLAST revealed high percentage identities to sequences from various CpGV isolates, resulting in the naming of the isolate in this study as the South African Cydia pomonella granulovirus (CpGV-SA) isolate. Phylogenetic analysis based on the single nucleotide polymorphisms (SNPs) detected in the lef-8, lef-9 and granulin nucleotide sequences grouped the South African isolate with CpGV-E2 (genome type B) and CpGV-S (genome type E). The CpGV-SA isolate was further genetically characterised by restriction endonuclease analysis and complete sequencing of the genomic DNA. Differences were observed for the BamHI, EcoRI, PstI and XhoI profiles of CpGV-SA in comparison to the respective profiles generated for CpGV-M extracted from a biopesticide, Carpovirusine® (Arysta Lifescience, France). Several genetic variations between the complete genome sequence of CpGV-SA and the reference isolate, CpGV-M1, as well as a recent genome submission of CpGV-M, both representing genome type A were observed. The complete genome analysis confirmed that CpGV-SA is genetically different from the Mexican CpGV isolate, used in thedevelopment of most biopesticides. In silico restriction profiles of the genome sequence obtained for CpGV-SA and genome sequences of genetically different CpGV isolates originating from Mexico (M1 and M), England (E2), Canada (S) and Iran (I12 and I07), available on the NCBI’s GenBank database confirmed that CpGV-SA is of mixed genotypes. Furthermore, the South African isolate shared the single common difference found in the pe38 gene of resistance overcoming isolates, which was the absence of an internal 24 nucleotide repeat present in CpGV-M1. In addition to the common difference, SNPs detected in the pe38 gene grouped the isolate with the CpGV-S isolate, suggesting that the CpGV-SA isolate is predominantly of genome type E. To determine the biological activity of CpGV-SA against neonate C. pomonella larvae, surface bioassays were conducted alongside CpGV-M (Carpovirusine®) bioassays. The LC50 and LC90 values for the South African isolate were 1.6 × 103 and 1.2 × 105 OBs/ml respectively. The LT50 was determined to be 135 hours. These values were similar to the values obtained for CpGV-M (Carpovirusine®). The results in this study suggest that a novel South African CpGV isolate of mixed genotypes, potentially able to overcome resistance in C. pomonella, with biological activity similar to CpGV-M (Carpovirusine®) and important for the control of C. pomonella was recovered. The CpGV-SA isolate could therefore potentially be developed into a biopesticide for use in resistance management strategies against C. pomonella populations in South Africa.
- Full Text:
- Authors: Motsoeneng, Boitumelo Madika
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:20503 , http://hdl.handle.net/10962/d1021266
- Description: The codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is the primary pest of pome fruit cultivated worldwide. The control of this insect pest has been dependent on the frequent use of broad-spectrum chemical pesticides, which has led to the development of resistance in pest populations and negative effects on human health and the environment. The Betabaculovirus of C. pomonella has successfully been applied as a biological control agent in integrated pest management (IPM) programmes for the suppression of pest populations worldwide. Previously, all Cydia pomonella granulovirus (CpGV) biopesticides were based on a Mexican isolate (CpGV-M) and although these products are highly efficient at controlling C. pomonella, resistance cases have been reported across Europe. The identification of novel CpGV isolates as additional or alternative control agents to manage resistance is therefore necessary. This study aimed to genetically and biologically characterise a novel South African C. pomonella granulovirus isolate and to test its virulence against neonate larvae. Based on the morphology of the occlusion bodies observed using transmission electron microscopy, granuloviruses were recovered from diseased and dead larvae collected from an orchard in South Africa where no virus applications had been made. DNA was extracted and the identification of the isolated granulovirus was achieved through the PCR amplification and sequencing of the lef-8, lef-9, granulin and egt genes. Submission of the gene sequences to BLAST revealed high percentage identities to sequences from various CpGV isolates, resulting in the naming of the isolate in this study as the South African Cydia pomonella granulovirus (CpGV-SA) isolate. Phylogenetic analysis based on the single nucleotide polymorphisms (SNPs) detected in the lef-8, lef-9 and granulin nucleotide sequences grouped the South African isolate with CpGV-E2 (genome type B) and CpGV-S (genome type E). The CpGV-SA isolate was further genetically characterised by restriction endonuclease analysis and complete sequencing of the genomic DNA. Differences were observed for the BamHI, EcoRI, PstI and XhoI profiles of CpGV-SA in comparison to the respective profiles generated for CpGV-M extracted from a biopesticide, Carpovirusine® (Arysta Lifescience, France). Several genetic variations between the complete genome sequence of CpGV-SA and the reference isolate, CpGV-M1, as well as a recent genome submission of CpGV-M, both representing genome type A were observed. The complete genome analysis confirmed that CpGV-SA is genetically different from the Mexican CpGV isolate, used in thedevelopment of most biopesticides. In silico restriction profiles of the genome sequence obtained for CpGV-SA and genome sequences of genetically different CpGV isolates originating from Mexico (M1 and M), England (E2), Canada (S) and Iran (I12 and I07), available on the NCBI’s GenBank database confirmed that CpGV-SA is of mixed genotypes. Furthermore, the South African isolate shared the single common difference found in the pe38 gene of resistance overcoming isolates, which was the absence of an internal 24 nucleotide repeat present in CpGV-M1. In addition to the common difference, SNPs detected in the pe38 gene grouped the isolate with the CpGV-S isolate, suggesting that the CpGV-SA isolate is predominantly of genome type E. To determine the biological activity of CpGV-SA against neonate C. pomonella larvae, surface bioassays were conducted alongside CpGV-M (Carpovirusine®) bioassays. The LC50 and LC90 values for the South African isolate were 1.6 × 103 and 1.2 × 105 OBs/ml respectively. The LT50 was determined to be 135 hours. These values were similar to the values obtained for CpGV-M (Carpovirusine®). The results in this study suggest that a novel South African CpGV isolate of mixed genotypes, potentially able to overcome resistance in C. pomonella, with biological activity similar to CpGV-M (Carpovirusine®) and important for the control of C. pomonella was recovered. The CpGV-SA isolate could therefore potentially be developed into a biopesticide for use in resistance management strategies against C. pomonella populations in South Africa.
- Full Text:
Genetic structure and biogeography of three wrasse species (Labridae) within the Western Indian Ocean
- Authors: Mayekiso, Sisanda
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/1114 , vital:20021
- Description: The biogeography of wrasses within the Western Indian Ocean (WIO) is poorly understood, with regard to origins and genetic differentiation or connectivity among the regions of the WIO. This region is a good model for studying the influence of physical complexities and biogeographic breaks in shaping patterns of differentiation in wrasses. Three reef-associated fish species, Cheilio inermis, Thalassoma hebraicum and T. lunare, were selected to examine the factors that have influenced patterns of differentiation across the WIO. Each species was sampled from various localities of the WIO, the Red Sea and Indo-West Pacific Islands. Sequence data were generated from two mitochondrial gene fragments (cytochrome b and ATPase 6) and one nuclear locus (the first intron of the ribosomal protein S7 gene). Genetic analyses were used to calculate genetic diversity indices within species, which were then compared among species. The relationships among haplotypes and alleles were constructed using median-joining networks. Where necessary, neighbour-joining trees (NJ) were constructed to examine relationships among haplotypes and alleles for the Thalassoma species. Population structure was analysed using AMOVA and pairwise ФST to compare and calculate differentiation between the WIO localities. Mismatch distributions were used to examine population growth and decline or stability, and demographic parameters were used to calculate time of population expansion. There was high haplotype (h = 0.88 to 0.98) and low nucleotide diversities (π = 0.003 to 0.008) among all species for mitochondrial markers. For S7 intron I, high allelic (A = 0.95 to 0.98) and low nucleotide diversities (π = 0.002 to 0.014) were observed for all species. The pairwise ФST values revealed little to great (ФST = -0.02 to 0.67) genetic differentiation between localities, across all species for the three gene regions. The pairwise comparisons indicated the differentiation in C. inermis of Tanzania and Kenya from Mozambique and Nosy Be (Madagascar). The widespread C. inermis also revealed the differentiation of Kenya and Tanzania. For C. inermis, the AMOVAs of ATPase 6 and cytochrome b data indicated high differentiation among defined locality groups. The groups were defined according to geographic proximity. However, the AMOVA of the nuclear gene (S7 intron I) did not find variation among defined locality groups. Cheilio inermis revealed a sequence divergence of 0.4%. The divergence that was found in C. inermis was not enough to suggest a cryptic species within the WIO. Overall, the widespread and monotypic C. inermis revealed genetic differentiation within the WIO. Thalassoma hebraicum generally revealed little genetic differentiation across the WIO. The AMOVAs of the three gene regions showed no variation among specimens of the defined locality groups. However, some differentiation was found between localities. The pairwise comparisons of T. hebraicum revealed the differentiation of Seychelles from the African mainland and Madagascar. Southern Africa was observed to be differentiated from Nosy Be and Zanzibar. The observed differentiation could be caused by oceanic barriers such as the South Equatorial Current (SEQC), East African Coastal Current (EACC), and the Comoros Gyres and eddies in the Mozambique Channel, and Agulhas Current. Thalassoma lunare revealed genetic isolation between the WIO and the Red Sea as well as within the WIO. The genetic isolation between the WIO and the Red Sea is probably due to the historical isolation by the Bab al Mandab and contemporary barriers such as the cold upwelling cells in Somalia. The differentiation of Maldives from the African mainland and Seychelles could be due to distance and the upwelling cells created by monsoon winds. Mismatch distributions suggested that C. inermis and T. hebraicum had undergone demographic expansion during the Pleistocene (92 678 to 40 219 years ago). The results of the current study are similar to those from previous studies of WIO reef fish species, and the results of the present study could have potential implications for conservation and fisheries management. Single genetic markers and single species studies do not detect all barriers to dispersal in the WIO, thus they are insufficient to inform conservation management. Thus, the use of multispecies and genetic markers in the current study can be adopted by other studies of the marine taxa of the WIO.
- Full Text:
- Authors: Mayekiso, Sisanda
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/1114 , vital:20021
- Description: The biogeography of wrasses within the Western Indian Ocean (WIO) is poorly understood, with regard to origins and genetic differentiation or connectivity among the regions of the WIO. This region is a good model for studying the influence of physical complexities and biogeographic breaks in shaping patterns of differentiation in wrasses. Three reef-associated fish species, Cheilio inermis, Thalassoma hebraicum and T. lunare, were selected to examine the factors that have influenced patterns of differentiation across the WIO. Each species was sampled from various localities of the WIO, the Red Sea and Indo-West Pacific Islands. Sequence data were generated from two mitochondrial gene fragments (cytochrome b and ATPase 6) and one nuclear locus (the first intron of the ribosomal protein S7 gene). Genetic analyses were used to calculate genetic diversity indices within species, which were then compared among species. The relationships among haplotypes and alleles were constructed using median-joining networks. Where necessary, neighbour-joining trees (NJ) were constructed to examine relationships among haplotypes and alleles for the Thalassoma species. Population structure was analysed using AMOVA and pairwise ФST to compare and calculate differentiation between the WIO localities. Mismatch distributions were used to examine population growth and decline or stability, and demographic parameters were used to calculate time of population expansion. There was high haplotype (h = 0.88 to 0.98) and low nucleotide diversities (π = 0.003 to 0.008) among all species for mitochondrial markers. For S7 intron I, high allelic (A = 0.95 to 0.98) and low nucleotide diversities (π = 0.002 to 0.014) were observed for all species. The pairwise ФST values revealed little to great (ФST = -0.02 to 0.67) genetic differentiation between localities, across all species for the three gene regions. The pairwise comparisons indicated the differentiation in C. inermis of Tanzania and Kenya from Mozambique and Nosy Be (Madagascar). The widespread C. inermis also revealed the differentiation of Kenya and Tanzania. For C. inermis, the AMOVAs of ATPase 6 and cytochrome b data indicated high differentiation among defined locality groups. The groups were defined according to geographic proximity. However, the AMOVA of the nuclear gene (S7 intron I) did not find variation among defined locality groups. Cheilio inermis revealed a sequence divergence of 0.4%. The divergence that was found in C. inermis was not enough to suggest a cryptic species within the WIO. Overall, the widespread and monotypic C. inermis revealed genetic differentiation within the WIO. Thalassoma hebraicum generally revealed little genetic differentiation across the WIO. The AMOVAs of the three gene regions showed no variation among specimens of the defined locality groups. However, some differentiation was found between localities. The pairwise comparisons of T. hebraicum revealed the differentiation of Seychelles from the African mainland and Madagascar. Southern Africa was observed to be differentiated from Nosy Be and Zanzibar. The observed differentiation could be caused by oceanic barriers such as the South Equatorial Current (SEQC), East African Coastal Current (EACC), and the Comoros Gyres and eddies in the Mozambique Channel, and Agulhas Current. Thalassoma lunare revealed genetic isolation between the WIO and the Red Sea as well as within the WIO. The genetic isolation between the WIO and the Red Sea is probably due to the historical isolation by the Bab al Mandab and contemporary barriers such as the cold upwelling cells in Somalia. The differentiation of Maldives from the African mainland and Seychelles could be due to distance and the upwelling cells created by monsoon winds. Mismatch distributions suggested that C. inermis and T. hebraicum had undergone demographic expansion during the Pleistocene (92 678 to 40 219 years ago). The results of the current study are similar to those from previous studies of WIO reef fish species, and the results of the present study could have potential implications for conservation and fisheries management. Single genetic markers and single species studies do not detect all barriers to dispersal in the WIO, thus they are insufficient to inform conservation management. Thus, the use of multispecies and genetic markers in the current study can be adopted by other studies of the marine taxa of the WIO.
- Full Text:
Geochemical exploration for copper - cobalt in the Democratic Republic of Congo, Central African Copperbelt: a case study on PR851
- Authors: Katombe-Kisumbule, Paul
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3035 , vital:20354
- Description: The PR851 licence area is located at about 80 km west from the town of Likasi in the district of Haut-Katanga and 175 km north-west of Lubumbashi, the capital city of Katanga Province in the Democratic Republic of Congo. The exploration licence was granted by the government of the Democratic Republic of Congo to First Quantum Minerals Ltd through its Congolese subsidiary Compagnie Minière de Sakania Sprl (CoMiSa Sprl) under certificate N˚ CAMI/CR/70/2003 on the 10th of October 2003 for a period of 5 years with a possibility of renewal for 3 years in respect to the new Congolese mining code. The PR851 area lies on fragments of Mines Subgroup rocks of the Roan Group in the Congolese Copperbelt where most of the Cu-Co and stratiform-stratabound deposits such as Kipushi, Ruashi-Etoile, Kinsevere, Kipoi, Luishya, Luswishi, Shituru, Kamoya, Kambove, Tenke- Fungurume, Shinkolobwe, Swambo, Mindingi and Kamoto among others are found. During the 20th century, the Union Minière du Haut Katanga (U.M.H.K.) undertook mineral exploration in the Congolese Copperbelt and numerous copper- and cobalt-occurrences were identified (for instance Kibamba copper occurrence in PR851 area). From 2003, the Compagnie Minière de Sakania Sprl initiated a grassroots exploration program in PR851 area and geochemical exploration survey as one of the mineral exploration tools was implemented to aim at detecting copper and cobalt concentration in soil. The B horizon of the thick tropical soil in the area was sampled and soil samples were sent to Genalysis laboratories in Johannesburg, Republic of South Africa for main chemical analysis of Cu and Co only, whereas 10% of analyzed samples were dispatched to Perth, Western Australia for quality control analysis. Thresholds for anomalies of copper and cobalt were defined by literature comparison, standard deviations and spatial analysis. The anomalies were tested at a later stage by reverse circulation / diamond drilling during the year of 2005 to 2008 and the Cu-Co resources were estimated by Digital Mining Services of Harare, Zimbabwe in the year of 2008. Geological logging of chips from reverse circulation and diamond drill cores revealed that copper mineralization is represented by malachite, chrysocolla, chalcopyrite and bornite whereas cobalt mineralization appeared in form of heterogenite. The source of supergene mineralization remains unknown. Recommendations have been made to undertake more geological exploration work in order to fully investigate the geological setting and structural architecture of the region, which may result in a better understanding of the Cu-Co mineralization system and ore genesis. The latter has been no consensus up-to-date and different theories have been proposed to discuss the ore genesis, including syn- and dia- genetic, synorogenic and sulphide remobilization to late-to-post- orogenic Cu-Zn-Pb Kipushi-type deposit. However, geological observations favored that the diagenetic and syngenetic models are applicable to numerous deposits in the Central African Copperbelt.
- Full Text:
- Authors: Katombe-Kisumbule, Paul
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3035 , vital:20354
- Description: The PR851 licence area is located at about 80 km west from the town of Likasi in the district of Haut-Katanga and 175 km north-west of Lubumbashi, the capital city of Katanga Province in the Democratic Republic of Congo. The exploration licence was granted by the government of the Democratic Republic of Congo to First Quantum Minerals Ltd through its Congolese subsidiary Compagnie Minière de Sakania Sprl (CoMiSa Sprl) under certificate N˚ CAMI/CR/70/2003 on the 10th of October 2003 for a period of 5 years with a possibility of renewal for 3 years in respect to the new Congolese mining code. The PR851 area lies on fragments of Mines Subgroup rocks of the Roan Group in the Congolese Copperbelt where most of the Cu-Co and stratiform-stratabound deposits such as Kipushi, Ruashi-Etoile, Kinsevere, Kipoi, Luishya, Luswishi, Shituru, Kamoya, Kambove, Tenke- Fungurume, Shinkolobwe, Swambo, Mindingi and Kamoto among others are found. During the 20th century, the Union Minière du Haut Katanga (U.M.H.K.) undertook mineral exploration in the Congolese Copperbelt and numerous copper- and cobalt-occurrences were identified (for instance Kibamba copper occurrence in PR851 area). From 2003, the Compagnie Minière de Sakania Sprl initiated a grassroots exploration program in PR851 area and geochemical exploration survey as one of the mineral exploration tools was implemented to aim at detecting copper and cobalt concentration in soil. The B horizon of the thick tropical soil in the area was sampled and soil samples were sent to Genalysis laboratories in Johannesburg, Republic of South Africa for main chemical analysis of Cu and Co only, whereas 10% of analyzed samples were dispatched to Perth, Western Australia for quality control analysis. Thresholds for anomalies of copper and cobalt were defined by literature comparison, standard deviations and spatial analysis. The anomalies were tested at a later stage by reverse circulation / diamond drilling during the year of 2005 to 2008 and the Cu-Co resources were estimated by Digital Mining Services of Harare, Zimbabwe in the year of 2008. Geological logging of chips from reverse circulation and diamond drill cores revealed that copper mineralization is represented by malachite, chrysocolla, chalcopyrite and bornite whereas cobalt mineralization appeared in form of heterogenite. The source of supergene mineralization remains unknown. Recommendations have been made to undertake more geological exploration work in order to fully investigate the geological setting and structural architecture of the region, which may result in a better understanding of the Cu-Co mineralization system and ore genesis. The latter has been no consensus up-to-date and different theories have been proposed to discuss the ore genesis, including syn- and dia- genetic, synorogenic and sulphide remobilization to late-to-post- orogenic Cu-Zn-Pb Kipushi-type deposit. However, geological observations favored that the diagenetic and syngenetic models are applicable to numerous deposits in the Central African Copperbelt.
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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:
- 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.
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Geospatial technologies and indigenous Knowledge Systems:
- Authors: Aswani, Shankar
- Date: 2016
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/145448 , vital:38439 , ISBN 9781315181523 , https://www.taylorfrancis.com/books/e/9781315181523/chapters/10.1201/9781315181523-18
- Description: During the twentieth and twenty-first centuries, pressure on coastal ecosystems has amplified and resulted in the widespread degradation of adjacent marine and terrestrial habitats globally (Burke et al., 2001). The ecosystem services provided by coastal habitats, including coastal protection and food procurement, have been heavily compromised by anthropogenic disturbance such as overfishing, pollution, sedimentation and alteration of coastal vegetation (Costanza et al., 1997; Agardy et al., 2009). In the context of small islands, this continued degradation in tandem with the ongoing effects of climate change is putting the livelihoods of coastal peoples at risk (e.g. Bell et al., 2009). While international efforts at curtailing these negative trends are ongoing, many researchers are working directly with coastal local/ indigenous communities to seek more effective management of coastal terrestrial and marine resources. Among various approaches, researchers are increasingly incorporating local knowledge systems for designing resource management and conservation plans (e.g. Gadgil et al., 1993).
- Full Text:
- Authors: Aswani, Shankar
- Date: 2016
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/145448 , vital:38439 , ISBN 9781315181523 , https://www.taylorfrancis.com/books/e/9781315181523/chapters/10.1201/9781315181523-18
- Description: During the twentieth and twenty-first centuries, pressure on coastal ecosystems has amplified and resulted in the widespread degradation of adjacent marine and terrestrial habitats globally (Burke et al., 2001). The ecosystem services provided by coastal habitats, including coastal protection and food procurement, have been heavily compromised by anthropogenic disturbance such as overfishing, pollution, sedimentation and alteration of coastal vegetation (Costanza et al., 1997; Agardy et al., 2009). In the context of small islands, this continued degradation in tandem with the ongoing effects of climate change is putting the livelihoods of coastal peoples at risk (e.g. Bell et al., 2009). While international efforts at curtailing these negative trends are ongoing, many researchers are working directly with coastal local/ indigenous communities to seek more effective management of coastal terrestrial and marine resources. Among various approaches, researchers are increasingly incorporating local knowledge systems for designing resource management and conservation plans (e.g. Gadgil et al., 1993).
- Full Text:
Global proliferation of cephalopods
- Doubleday, Zoë A, Prowse, Thomas A A, Arkhipkin, Alexander, Pierce, Graham J, Semmens, Jayson, Steer, Michael, Leporati, Stephen C, Lourenço, Sílvia, Quetglas, Antoni, Sauer, Warwick H H, Gillanders, Bronwyn M
- Authors: Doubleday, Zoë A , Prowse, Thomas A A , Arkhipkin, Alexander , Pierce, Graham J , Semmens, Jayson , Steer, Michael , Leporati, Stephen C , Lourenço, Sílvia , Quetglas, Antoni , Sauer, Warwick H H , Gillanders, Bronwyn M
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124560 , vital:35628 , https://doi.10.1016/j.cub.2016.04.002
- Description: Human activities have substantially changed the world’s oceans in recent decades, altering marine food webs, habitats and biogeochemical processes [1]. Cephalopods (squid, cuttlefish and octopuses) have a unique set of biological traits, including rapid growth, short lifespans and strong life-history plasticity, allowing them to adapt quickly to changing environmental conditions [2–4]. There has been growing speculation that cephalopod populations are proliferating in response to a changing environment, a perception fuelled by increasing trends in cephalopod fisheries catch [4,5]. To investigate long-term trends in cephalopod abundance, we assembled global time-series of cephalopod catch rates (catch per unit of fishing or sampling effort). We show that cephalopod populations have increased over the last six decades, a result that was remarkably consistent across a highly diverse set of cephalopod taxa. Positive trends were also evident for both fisheries-dependent and fisheries independent time-series, suggesting that trends are not solely due to factors associated with developing fisheries. Our results suggest that large-scale, directional processes, common to a range of coastal and oceanic environments, are responsible. This study presents the first evidence that cephalopod populations have increased globally, indicating that these ecologically and commercially important invertebrates may have benefited from a changing ocean environment.
- Full Text:
- Authors: Doubleday, Zoë A , Prowse, Thomas A A , Arkhipkin, Alexander , Pierce, Graham J , Semmens, Jayson , Steer, Michael , Leporati, Stephen C , Lourenço, Sílvia , Quetglas, Antoni , Sauer, Warwick H H , Gillanders, Bronwyn M
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124560 , vital:35628 , https://doi.10.1016/j.cub.2016.04.002
- Description: Human activities have substantially changed the world’s oceans in recent decades, altering marine food webs, habitats and biogeochemical processes [1]. Cephalopods (squid, cuttlefish and octopuses) have a unique set of biological traits, including rapid growth, short lifespans and strong life-history plasticity, allowing them to adapt quickly to changing environmental conditions [2–4]. There has been growing speculation that cephalopod populations are proliferating in response to a changing environment, a perception fuelled by increasing trends in cephalopod fisheries catch [4,5]. To investigate long-term trends in cephalopod abundance, we assembled global time-series of cephalopod catch rates (catch per unit of fishing or sampling effort). We show that cephalopod populations have increased over the last six decades, a result that was remarkably consistent across a highly diverse set of cephalopod taxa. Positive trends were also evident for both fisheries-dependent and fisheries independent time-series, suggesting that trends are not solely due to factors associated with developing fisheries. Our results suggest that large-scale, directional processes, common to a range of coastal and oceanic environments, are responsible. This study presents the first evidence that cephalopod populations have increased globally, indicating that these ecologically and commercially important invertebrates may have benefited from a changing ocean environment.
- Full Text: