Postgraduate writing groups as spaces of agency development
- Oluwole, David O, Achadu, A, Asfour, Fouad-Martin, Chakona, Gamuchirai, Mason, Paul, Mataruse, P, McKenna, Sioux
- Authors: Oluwole, David O , Achadu, A , Asfour, Fouad-Martin , Chakona, Gamuchirai , Mason, Paul , Mataruse, P , McKenna, Sioux
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187194 , vital:44578 , xlink:href="https://doi.org/10.20853/32-6-2963"
- Description: Academic writing is a peculiar phenomenon – it varies greatly from discipline to discipline and its requirements are rarely made overt. Taking on the writing practices of the academy has implications for identity and it is thus unsurprising that it is seen to be a risky endeavour. This article analyses the experiences of postgraduate scholars who have participated in writing groups that meet weekly to read each other’s work and provide supportive critique. Thirty-two people provided detailed, anonymous evaluations of their writing groups and these were studied using a discourse analysis. Three main findings are discussed here. Firstly, writing circles allowed for academic writing development to be engaged with as a social practice, where the disciplinary norms could be made more explicit through peer deliberation, and where they could also be challenged. Secondly, the lack of hierarchical power in the writing groups was key to making safe spaces for agency development, and also for providing positive peer pressure whereby participants were spurred on to work on their writing. Thirdly, the fact that the groups were interdisciplinary, within cognate disciplinary families, provided an interesting challenge in that the students had to consider what these non-specialist readers would or would not understand. This process assisted students in clarifying their writing. Participants’ evaluation of the writing groups revealed an overall sense that these contributed to postgraduate student wellbeing and were places of significant agential development.
- Full Text:
- Date Issued: 2018
- Authors: Oluwole, David O , Achadu, A , Asfour, Fouad-Martin , Chakona, Gamuchirai , Mason, Paul , Mataruse, P , McKenna, Sioux
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187194 , vital:44578 , xlink:href="https://doi.org/10.20853/32-6-2963"
- Description: Academic writing is a peculiar phenomenon – it varies greatly from discipline to discipline and its requirements are rarely made overt. Taking on the writing practices of the academy has implications for identity and it is thus unsurprising that it is seen to be a risky endeavour. This article analyses the experiences of postgraduate scholars who have participated in writing groups that meet weekly to read each other’s work and provide supportive critique. Thirty-two people provided detailed, anonymous evaluations of their writing groups and these were studied using a discourse analysis. Three main findings are discussed here. Firstly, writing circles allowed for academic writing development to be engaged with as a social practice, where the disciplinary norms could be made more explicit through peer deliberation, and where they could also be challenged. Secondly, the lack of hierarchical power in the writing groups was key to making safe spaces for agency development, and also for providing positive peer pressure whereby participants were spurred on to work on their writing. Thirdly, the fact that the groups were interdisciplinary, within cognate disciplinary families, provided an interesting challenge in that the students had to consider what these non-specialist readers would or would not understand. This process assisted students in clarifying their writing. Participants’ evaluation of the writing groups revealed an overall sense that these contributed to postgraduate student wellbeing and were places of significant agential development.
- Full Text:
- Date Issued: 2018
Potential impact and host range of Pereskiophaga brasiliensis Anderson (Curculionidae): a new candidate biological control agent for the control of Pereskia aculeata Miller (Cactaceae) in South Africa
- Authors: Mdodana, Lumka Anita
- Date: 2018
- Subjects: Curculionidae -- South Africa , Cactus -- South Africa , Biological pest control agents , Alien plants-- South Africa , Pereskiophaga brasiliensis Anderson (Curculionidae) , Pereskia aculeata Miller (Cactaceae)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62350 , vital:28157
- Description: Pereskia aculeata Miller (Cactaceae) is a damaging invasive alien plant in South Africa that has negative impacts to indigenous biodiversity and ecosystem functioning. Mechanical and chemical control are not effective against P. aculeata so biological control is considered the only viable option. Two biological control agents, the leaf-feeding beetle Phenrica guerini Bechyne (Chrysomelidae) and the stem-wilting bug Catorhintha schaffneri (Coreidae), have been released in South Africa thus far. Post-release evaluations have indicated that P. guerini will not reduce P. aculeata densities to acceptable levels alone, while C. schaffneri was released very recently, so it is too soon to determine how effective that agent will be. Even if C. schaffneri is extremely damaging, it is likely that further agents will be required to reduce the densities of P. aculeata to acceptable levels within a reasonable time-scale. Additional agents should target the woody stems of P. aculeata which are not impacted by the damage of either of the released agents. Pereskiophaga brasiliensis Anderson (Curculionidae) is a promising potential candidate agent that feeds on the thick woody stems of the plant in the larval stage. Climatic matching, genetic matching and field based host specificity observations all indicated that P. brasiliensis was a promising candidate. In this study, the impact of P. brasiliensis to the target weed, P. aculeata, was quantified under quarantine conditions to determine whether it was sufficiently damaging to warrant release. This was followed by host specificity testing to determine whether P. brasiliensis was suitably host specific for release in South Africa. Impact studies indicated that P. brasiliensis was damaging to P. aculeata at insect densities that would be expected in the field. Pereskiophaga brasiliensis reduced the number of leaves of P. aculeata to a greater extent than it reduced shoot lengths, but both plant parameters were significantly reduced due to the feeding damage from the insect. This suggests that the damage from P. brasiliensis may be compatible with that of C. schaffneri which reduces shoot length to a greater degree than the number of leaves. Pereskiophaga brasiliensis is therefore sufficiently damaging to warrant release, and although interaction studies with the other agents would be required, it is expected that it should complement other existing agents. Although P. brasiliensis is sufficiently damaging, at present the host specificity data indicates that it is not suitably specific for release in South Africa because oviposition and larval development to the adult stage was recorded on both indigenous and alien plant species within the families Cactaceae and Basellaceae. This non-target feeding was recorded during no-choice tests, which are very conservative, but significant non-target damage and development to the adult stage was recorded on an indigenous plant from a different family to the target weed. Further host specificity testing, including paired and multiple choice tests, are required to confirm the broad host range of P. brasiliensis. Other biological control agents that damage the woody stems of P. aculeata should be considered. The stem-borer, Acanthodoxus machacalis (Cerambycidae) is considered the most promising of the other candidate agents as it can be sourced from a climatically matched region where genetically suitable P. aculeata plants are found, it is sufficiently damaging to the woody stems of P. aculeata and there is no evidence that the species has a broad host range. Acanthodoxus machacalis should be sourced from Rio de Janeiro, Brazil, and imported into quarantine in South Africa for host specificity testing.
- Full Text:
- Date Issued: 2018
- Authors: Mdodana, Lumka Anita
- Date: 2018
- Subjects: Curculionidae -- South Africa , Cactus -- South Africa , Biological pest control agents , Alien plants-- South Africa , Pereskiophaga brasiliensis Anderson (Curculionidae) , Pereskia aculeata Miller (Cactaceae)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62350 , vital:28157
- Description: Pereskia aculeata Miller (Cactaceae) is a damaging invasive alien plant in South Africa that has negative impacts to indigenous biodiversity and ecosystem functioning. Mechanical and chemical control are not effective against P. aculeata so biological control is considered the only viable option. Two biological control agents, the leaf-feeding beetle Phenrica guerini Bechyne (Chrysomelidae) and the stem-wilting bug Catorhintha schaffneri (Coreidae), have been released in South Africa thus far. Post-release evaluations have indicated that P. guerini will not reduce P. aculeata densities to acceptable levels alone, while C. schaffneri was released very recently, so it is too soon to determine how effective that agent will be. Even if C. schaffneri is extremely damaging, it is likely that further agents will be required to reduce the densities of P. aculeata to acceptable levels within a reasonable time-scale. Additional agents should target the woody stems of P. aculeata which are not impacted by the damage of either of the released agents. Pereskiophaga brasiliensis Anderson (Curculionidae) is a promising potential candidate agent that feeds on the thick woody stems of the plant in the larval stage. Climatic matching, genetic matching and field based host specificity observations all indicated that P. brasiliensis was a promising candidate. In this study, the impact of P. brasiliensis to the target weed, P. aculeata, was quantified under quarantine conditions to determine whether it was sufficiently damaging to warrant release. This was followed by host specificity testing to determine whether P. brasiliensis was suitably host specific for release in South Africa. Impact studies indicated that P. brasiliensis was damaging to P. aculeata at insect densities that would be expected in the field. Pereskiophaga brasiliensis reduced the number of leaves of P. aculeata to a greater extent than it reduced shoot lengths, but both plant parameters were significantly reduced due to the feeding damage from the insect. This suggests that the damage from P. brasiliensis may be compatible with that of C. schaffneri which reduces shoot length to a greater degree than the number of leaves. Pereskiophaga brasiliensis is therefore sufficiently damaging to warrant release, and although interaction studies with the other agents would be required, it is expected that it should complement other existing agents. Although P. brasiliensis is sufficiently damaging, at present the host specificity data indicates that it is not suitably specific for release in South Africa because oviposition and larval development to the adult stage was recorded on both indigenous and alien plant species within the families Cactaceae and Basellaceae. This non-target feeding was recorded during no-choice tests, which are very conservative, but significant non-target damage and development to the adult stage was recorded on an indigenous plant from a different family to the target weed. Further host specificity testing, including paired and multiple choice tests, are required to confirm the broad host range of P. brasiliensis. Other biological control agents that damage the woody stems of P. aculeata should be considered. The stem-borer, Acanthodoxus machacalis (Cerambycidae) is considered the most promising of the other candidate agents as it can be sourced from a climatically matched region where genetically suitable P. aculeata plants are found, it is sufficiently damaging to the woody stems of P. aculeata and there is no evidence that the species has a broad host range. Acanthodoxus machacalis should be sourced from Rio de Janeiro, Brazil, and imported into quarantine in South Africa for host specificity testing.
- Full Text:
- Date Issued: 2018
Potential latitudinal variation in orodigestive tract cancers in Africa
- Adeola, H A, Adefuye, A O, Jimoh, S A
- Authors: Adeola, H A , Adefuye, A O , Jimoh, S A
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5280 , vital:44428 , http://www.samj.org.za/index.php/samj/article/view/12259
- Description: Background. Previous studies have alluded to a causal relationship between pathological entities and geographical variations, but there is a paucity of studies from Africa discussing the effect of latitudinal variation on orodigestive cancers in this region. It seems plausible that the burden of orodigestive cancer would differ as a result of variations in diet, cultural habits, climate and environmental conditions down the length of Africa. Objectives. To analyse regional variations in prevalence, incidence and mortality data in the global cancer statistics database (GLOBOCAN 2012) curated by the World Health Organization and the International Agency for Research on Cancer. Basic descriptive statistical tools were used to depict regional variations in cancer morbidity and mortality. Methods. Data on 13 African countries between longitude 20⁰ and 30⁰ east and latitude 35⁰ north and 35⁰ south were examined for variation in age-standardised orodigestive cancer prevalence, incidence and mortality. Possible regional causes for orodigestive tract cancer development were investigated. Data on lip and oral cavity, oesophageal, gastric, colorectal, liver, gallbladder and pancreatic cancers in the 13 countries were compared. Results. Our empirical findings from this preliminary study support the notion that the incidence and prevalence of orodigestive cancers vary within Africa. This effect may be due to environmental, economic, political and possibly genetic factors. Conclusions. Considering the heterogeneity of the above factors across Africa, disbursement of funding for cancer research and therapy in Africa should be focused in terms of regional variations to make best use of the fiscal allocation by African governments, non-governmental organisations and international agencies.
- Full Text:
- Date Issued: 2018
- Authors: Adeola, H A , Adefuye, A O , Jimoh, S A
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5280 , vital:44428 , http://www.samj.org.za/index.php/samj/article/view/12259
- Description: Background. Previous studies have alluded to a causal relationship between pathological entities and geographical variations, but there is a paucity of studies from Africa discussing the effect of latitudinal variation on orodigestive cancers in this region. It seems plausible that the burden of orodigestive cancer would differ as a result of variations in diet, cultural habits, climate and environmental conditions down the length of Africa. Objectives. To analyse regional variations in prevalence, incidence and mortality data in the global cancer statistics database (GLOBOCAN 2012) curated by the World Health Organization and the International Agency for Research on Cancer. Basic descriptive statistical tools were used to depict regional variations in cancer morbidity and mortality. Methods. Data on 13 African countries between longitude 20⁰ and 30⁰ east and latitude 35⁰ north and 35⁰ south were examined for variation in age-standardised orodigestive cancer prevalence, incidence and mortality. Possible regional causes for orodigestive tract cancer development were investigated. Data on lip and oral cavity, oesophageal, gastric, colorectal, liver, gallbladder and pancreatic cancers in the 13 countries were compared. Results. Our empirical findings from this preliminary study support the notion that the incidence and prevalence of orodigestive cancers vary within Africa. This effect may be due to environmental, economic, political and possibly genetic factors. Conclusions. Considering the heterogeneity of the above factors across Africa, disbursement of funding for cancer research and therapy in Africa should be focused in terms of regional variations to make best use of the fiscal allocation by African governments, non-governmental organisations and international agencies.
- Full Text:
- Date Issued: 2018
Practical application of distributed ledger technology in support of digital evidence integrity verification processes
- Authors: Weilbach, William Thomas
- Date: 2018
- Subjects: Digital forensic science , Blockchains (Databases) , Bitcoin , Distributed databases , Computer systems Verification
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61872 , vital:28070
- Description: After its birth in cryptocurrencies, distributed ledger (blockchain) technology rapidly grew in popularity in other technology domains. Alternative applications of this technology range from digitizing the bank guarantees process for commercial property leases (Anz and IBM, 2017) to tracking the provenance of high-value physical goods (Everledger Ltd., 2017). As a whole, distributed ledger technology has acted as a catalyst to the rise of many innovative alternative solutions to existing problems, mostly associated with trust and integrity. In this research, a niche application of this technology is proposed for use in digital forensics by providing a mechanism for the transparent and irrefutable verification of digital evidence, ensuring its integrity as established blockchains serve as an ideal mechanism to store and validate arbitrary data against. Evaluation and identification of candidate technologies in this domain is based on a set of requirements derived from previous work in this field (Weilbach, 2014). OpenTimestamps (Todd, 2016b) is chosen as the foundation of further work for its robust architecture, transparent nature and multi-platform support. A robust evaluation and discussion of OpenTimestamps is performed to reinforce why it can be trusted as an implementation and protocol. An implementation of OpenTimestamps is designed for the popular open source forensic tool, Autopsy, and an Autopsy module is subsequently developed and released to the public. OpenTimestamps is tested at scale and found to have insignificant error rates for the verification of timestamps. Through practical implementation and extensive testing, it is shown that OpenTimestamps has the potential to significantly advance the practice of digital evidence integrity verification. A conclusion is reached by discussing some of the limitations of OpenTimestamps in terms of accuracy and error rates. It is shown that although OpenTimestamps has very specific timing claims in the attestation, with a near zero error rate, the actual attestation is truly accurate to within a day. This is followed by proposing potential avenues for future work.
- Full Text:
- Date Issued: 2018
- Authors: Weilbach, William Thomas
- Date: 2018
- Subjects: Digital forensic science , Blockchains (Databases) , Bitcoin , Distributed databases , Computer systems Verification
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61872 , vital:28070
- Description: After its birth in cryptocurrencies, distributed ledger (blockchain) technology rapidly grew in popularity in other technology domains. Alternative applications of this technology range from digitizing the bank guarantees process for commercial property leases (Anz and IBM, 2017) to tracking the provenance of high-value physical goods (Everledger Ltd., 2017). As a whole, distributed ledger technology has acted as a catalyst to the rise of many innovative alternative solutions to existing problems, mostly associated with trust and integrity. In this research, a niche application of this technology is proposed for use in digital forensics by providing a mechanism for the transparent and irrefutable verification of digital evidence, ensuring its integrity as established blockchains serve as an ideal mechanism to store and validate arbitrary data against. Evaluation and identification of candidate technologies in this domain is based on a set of requirements derived from previous work in this field (Weilbach, 2014). OpenTimestamps (Todd, 2016b) is chosen as the foundation of further work for its robust architecture, transparent nature and multi-platform support. A robust evaluation and discussion of OpenTimestamps is performed to reinforce why it can be trusted as an implementation and protocol. An implementation of OpenTimestamps is designed for the popular open source forensic tool, Autopsy, and an Autopsy module is subsequently developed and released to the public. OpenTimestamps is tested at scale and found to have insignificant error rates for the verification of timestamps. Through practical implementation and extensive testing, it is shown that OpenTimestamps has the potential to significantly advance the practice of digital evidence integrity verification. A conclusion is reached by discussing some of the limitations of OpenTimestamps in terms of accuracy and error rates. It is shown that although OpenTimestamps has very specific timing claims in the attestation, with a near zero error rate, the actual attestation is truly accurate to within a day. This is followed by proposing potential avenues for future work.
- Full Text:
- Date Issued: 2018
Practice intentions at entry to and exit from medical schools aspiring to social accountability: findings from the Training for Health Equity Network Graduate Outcome Study
- Iputo, Jehu, Sarah Larkins , Karen Johnston, John C. Hogenbirk, Sara Willems, Salwa Elsanousi, Marykutty Mammen, Kaatje Van Roy, Jehu Iputo , Fortunato L. Cristobal , Jennene Greenhill, Charlie Labarda11 and Andre-Jacques Neusy
- Authors: Iputo, Jehu , Sarah Larkins , Karen Johnston, John C. Hogenbirk, Sara Willems, Salwa Elsanousi, Marykutty Mammen, Kaatje Van Roy, Jehu Iputo , Fortunato L. Cristobal , Jennene Greenhill, Charlie Labarda11 and Andre-Jacques Neusy
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5415 , vital:44567 , https://pubmed.ncbi.nlm.nih.gov/30424760/
- Description: Background: Understanding the impact of selection and medical education on practice intentions and eventual practice is an essential component of training a fit-for-purpose health workforce distributed according to population need. Existing evidence comes largely from high-income settings and neglects contextual factors. This paper describes the practice intentions of entry and exit cohorts of medical students across low and high income settings and the correlation of student characteristics with these intentions. Methods: The Training for Health Equity Network (THEnet) Graduate Outcome Study (GOS) is an international prospective cohort study tracking learners throughout training and ten years into practice as part of the longitudinal impact assessment described in THEnet’s Evaluation Framework. THEnet is an international community of practice of twelve medical schools with a social accountability mandate. Data presented here include cross-sectional entry and exit data obtained from different cohorts of medical students involving eight medical schools in six countries and five continents. Binary logistic regression was used to create adjusted odds ratios for associations with practice intent. Results: Findings from 3346 learners from eight THEnet medical schools in 6 countries collected between 2012 and 2016 are presented. A high proportion of study respondents at these schools come from rural and disadvantaged backgrounds and these respondents are more likely than others to express an intention to work in underserved locations after graduation at both entry and exit from medical school. After adjusting for confounding factors, rural and low income background and regional location of medical school were the most important predictors of intent to practice in a rural location. For schools in the Philippines and Africa, intention to emigrate was more likely for respondents from high income and urban backgrounds.
- Full Text:
- Date Issued: 2018
- Authors: Iputo, Jehu , Sarah Larkins , Karen Johnston, John C. Hogenbirk, Sara Willems, Salwa Elsanousi, Marykutty Mammen, Kaatje Van Roy, Jehu Iputo , Fortunato L. Cristobal , Jennene Greenhill, Charlie Labarda11 and Andre-Jacques Neusy
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5415 , vital:44567 , https://pubmed.ncbi.nlm.nih.gov/30424760/
- Description: Background: Understanding the impact of selection and medical education on practice intentions and eventual practice is an essential component of training a fit-for-purpose health workforce distributed according to population need. Existing evidence comes largely from high-income settings and neglects contextual factors. This paper describes the practice intentions of entry and exit cohorts of medical students across low and high income settings and the correlation of student characteristics with these intentions. Methods: The Training for Health Equity Network (THEnet) Graduate Outcome Study (GOS) is an international prospective cohort study tracking learners throughout training and ten years into practice as part of the longitudinal impact assessment described in THEnet’s Evaluation Framework. THEnet is an international community of practice of twelve medical schools with a social accountability mandate. Data presented here include cross-sectional entry and exit data obtained from different cohorts of medical students involving eight medical schools in six countries and five continents. Binary logistic regression was used to create adjusted odds ratios for associations with practice intent. Results: Findings from 3346 learners from eight THEnet medical schools in 6 countries collected between 2012 and 2016 are presented. A high proportion of study respondents at these schools come from rural and disadvantaged backgrounds and these respondents are more likely than others to express an intention to work in underserved locations after graduation at both entry and exit from medical school. After adjusting for confounding factors, rural and low income background and regional location of medical school were the most important predictors of intent to practice in a rural location. For schools in the Philippines and Africa, intention to emigrate was more likely for respondents from high income and urban backgrounds.
- Full Text:
- Date Issued: 2018
Practising Adaptive IWRM (Integrated Water Resources Management) in South Africa
- Palmer, Carolyn G, Munnik, Victor, du Toit, Derick, Rogers, Kevin H, Pollard, Sharon, Hamer, Nick, Weaver, Matthew J T, Retief, Hugo, Sahula, Asiphe, O’Keeffe, Jay H
- Authors: Palmer, Carolyn G , Munnik, Victor , du Toit, Derick , Rogers, Kevin H , Pollard, Sharon , Hamer, Nick , Weaver, Matthew J T , Retief, Hugo , Sahula, Asiphe , O’Keeffe, Jay H
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438005 , vital:73428 , ISBN 978-1-4312-0983-5 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2248-1-18.pdf
- Description: This chapter serves as a general introduction to the TPNP case stud-ies, with feedback from the progress of the RESILIM-O project. We draw attention here, and note clearly, that each case is set in a different context and scale, and proceeded in different ways, as well as combin-ing in use different discourses/practices and methodologies. To ensure a basis for comparability, each case study was required to use the Adaptive IWRM approach and methodologies, while not being required to record results in the same format. Case studies were designed to enable an exploration of scale effects–a core theoretical concept in complex social-ecological systems. We will be in a position to write a scholarly paper on a scale-comparison of practice-based Adaptive IWRM learning at different spatial and governance (institutional and social) scales, as a result of these findings.
- Full Text:
- Date Issued: 2018
- Authors: Palmer, Carolyn G , Munnik, Victor , du Toit, Derick , Rogers, Kevin H , Pollard, Sharon , Hamer, Nick , Weaver, Matthew J T , Retief, Hugo , Sahula, Asiphe , O’Keeffe, Jay H
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438005 , vital:73428 , ISBN 978-1-4312-0983-5 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2248-1-18.pdf
- Description: This chapter serves as a general introduction to the TPNP case stud-ies, with feedback from the progress of the RESILIM-O project. We draw attention here, and note clearly, that each case is set in a different context and scale, and proceeded in different ways, as well as combin-ing in use different discourses/practices and methodologies. To ensure a basis for comparability, each case study was required to use the Adaptive IWRM approach and methodologies, while not being required to record results in the same format. Case studies were designed to enable an exploration of scale effects–a core theoretical concept in complex social-ecological systems. We will be in a position to write a scholarly paper on a scale-comparison of practice-based Adaptive IWRM learning at different spatial and governance (institutional and social) scales, as a result of these findings.
- Full Text:
- Date Issued: 2018
Pregnant women’s construction of social support from their intimate partners during pregnancy
- Authors: Bottoman, Phathiswa Esona
- Date: 2018
- Subjects: Pregnant women -- South Africa -- Eastern Cape -- Relations with men Pregnancy -- Psychological aspects Pregnant women -- Social conditions
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/62560 , vital:28207
- Description: There is a growing body of research aimed at understanding social support during pregnancy in South Africa. Pregnancy is constantly referred to as one of the challenging and stressful periods affecting women’s physical and psychological well-being. Various research studies on social support argue that social support is paramount at this stage. Research on social support indicates that having adequate and quality social support impacts on how pregnant women experience pregnancy. My interest in social support comes in the wake of absent fathers in South Africa and with the emerging trend of “new” fathers. Although there is a volume of research on social support, it tends to be realist. Using a social constructionist framework, I explore other ways of talking about social support in an attempt to expand the discourse around social support. I explore how pregnant women talk about social support during pregnancy from their intimate partners in the small rural municipality of Elundini, Eastern Cape, South Africa. Intimate partner support was limited to heterosexual partners regardless of their marital status. The sampling procedure followed a non-probability sampling method. Participants of the study were between 24 and 32 years old. Their gestational age ranged between five and eight months. Fourteen in-depth interviews using photo-elicitation were conducted with seven participants and were analysed using a social constructionist informed thematic analysis. The major theme that emerged from the analysis was partner involvement and absence during pregnancy. The analysis of results suggests that expectant father presence translates to social support. Participants constructed his presence as reassurance in the context of possible abandonment. Absence was constructed in different ways: participants constructed absence as unjust and unfair, absence and marriage, temporary absence in the form of cultural phenomenon of ukwaliswa/ukubukubazana, absence as normal but burdening to the pregnant women’s social network. Participants reported that social support from the expectant father affected pregnancy wantedness.
- Full Text:
- Date Issued: 2018
- Authors: Bottoman, Phathiswa Esona
- Date: 2018
- Subjects: Pregnant women -- South Africa -- Eastern Cape -- Relations with men Pregnancy -- Psychological aspects Pregnant women -- Social conditions
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/62560 , vital:28207
- Description: There is a growing body of research aimed at understanding social support during pregnancy in South Africa. Pregnancy is constantly referred to as one of the challenging and stressful periods affecting women’s physical and psychological well-being. Various research studies on social support argue that social support is paramount at this stage. Research on social support indicates that having adequate and quality social support impacts on how pregnant women experience pregnancy. My interest in social support comes in the wake of absent fathers in South Africa and with the emerging trend of “new” fathers. Although there is a volume of research on social support, it tends to be realist. Using a social constructionist framework, I explore other ways of talking about social support in an attempt to expand the discourse around social support. I explore how pregnant women talk about social support during pregnancy from their intimate partners in the small rural municipality of Elundini, Eastern Cape, South Africa. Intimate partner support was limited to heterosexual partners regardless of their marital status. The sampling procedure followed a non-probability sampling method. Participants of the study were between 24 and 32 years old. Their gestational age ranged between five and eight months. Fourteen in-depth interviews using photo-elicitation were conducted with seven participants and were analysed using a social constructionist informed thematic analysis. The major theme that emerged from the analysis was partner involvement and absence during pregnancy. The analysis of results suggests that expectant father presence translates to social support. Participants constructed his presence as reassurance in the context of possible abandonment. Absence was constructed in different ways: participants constructed absence as unjust and unfair, absence and marriage, temporary absence in the form of cultural phenomenon of ukwaliswa/ukubukubazana, absence as normal but burdening to the pregnant women’s social network. Participants reported that social support from the expectant father affected pregnancy wantedness.
- Full Text:
- Date Issued: 2018
Preimages for SHA-1
- Authors: Motara, Yusuf Moosa
- Date: 2018
- Subjects: Data encryption (Computer science) , Computer security -- Software , Hashing (Computer science) , Data compression (Computer science) , Preimage , Secure Hash Algorithm 1 (SHA-1)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/57885 , vital:27004
- Description: This research explores the problem of finding a preimage — an input that, when passed through a particular function, will result in a pre-specified output — for the compression function of the SHA-1 cryptographic hash. This problem is much more difficult than the problem of finding a collision for a hash function, and preimage attacks for very few popular hash functions are known. The research begins by introducing the field and giving an overview of the existing work in the area. A thorough analysis of the compression function is made, resulting in alternative formulations for both parts of the function, and both statistical and theoretical tools to determine the difficulty of the SHA-1 preimage problem. Different representations (And- Inverter Graph, Binary Decision Diagram, Conjunctive Normal Form, Constraint Satisfaction form, and Disjunctive Normal Form) and associated tools to manipulate and/or analyse these representations are then applied and explored, and results are collected and interpreted. In conclusion, the SHA-1 preimage problem remains unsolved and insoluble for the foreseeable future. The primary issue is one of efficient representation; despite a promising theoretical difficulty, both the diffusion characteristics and the depth of the tree stand in the way of efficient search. Despite this, the research served to confirm and quantify the difficulty of the problem both theoretically, using Schaefer's Theorem, and practically, in the context of different representations.
- Full Text:
- Date Issued: 2018
- Authors: Motara, Yusuf Moosa
- Date: 2018
- Subjects: Data encryption (Computer science) , Computer security -- Software , Hashing (Computer science) , Data compression (Computer science) , Preimage , Secure Hash Algorithm 1 (SHA-1)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/57885 , vital:27004
- Description: This research explores the problem of finding a preimage — an input that, when passed through a particular function, will result in a pre-specified output — for the compression function of the SHA-1 cryptographic hash. This problem is much more difficult than the problem of finding a collision for a hash function, and preimage attacks for very few popular hash functions are known. The research begins by introducing the field and giving an overview of the existing work in the area. A thorough analysis of the compression function is made, resulting in alternative formulations for both parts of the function, and both statistical and theoretical tools to determine the difficulty of the SHA-1 preimage problem. Different representations (And- Inverter Graph, Binary Decision Diagram, Conjunctive Normal Form, Constraint Satisfaction form, and Disjunctive Normal Form) and associated tools to manipulate and/or analyse these representations are then applied and explored, and results are collected and interpreted. In conclusion, the SHA-1 preimage problem remains unsolved and insoluble for the foreseeable future. The primary issue is one of efficient representation; despite a promising theoretical difficulty, both the diffusion characteristics and the depth of the tree stand in the way of efficient search. Despite this, the research served to confirm and quantify the difficulty of the problem both theoretically, using Schaefer's Theorem, and practically, in the context of different representations.
- Full Text:
- Date Issued: 2018
Price determination of non-timber forest products in different areas of South Africa
- Mugido, Worship, Shackleton, Charlie M
- Authors: Mugido, Worship , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179825 , vital:43192 , xlink:href="https://doi.org/10.1016/j.ecolecon.2017.12.010"
- Description: A wide variety of factors can influence the price determination of non-timber forest products (NTFPs) in individual markets. However, there is little understanding of differences across multiple markets within a uniform macro context, or how they might vary between different types of NTFPs. Therefore, this study sought to determine the factors and rationale behind the setting of prices for selected NTFPs in 15 different areas of South Africa. The results showed that the pricing factors considered by sellers when setting the prices of NTFP varied with the type of NTFP being sold, type of market (home markets or urban markets) and the method used by the seller to procure the stock. Overall, transport costs, stock price, profit margin, time taken to collect or produce the product and market price were the widely used factors to determine prices for NTFPs. The marked variation in both markets and products show that there was no formal or certain price setting mechanism that was used by NTFP sellers establish the market prices of NTFPs, with price discovery being the most widespread.
- Full Text:
- Date Issued: 2018
- Authors: Mugido, Worship , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179825 , vital:43192 , xlink:href="https://doi.org/10.1016/j.ecolecon.2017.12.010"
- Description: A wide variety of factors can influence the price determination of non-timber forest products (NTFPs) in individual markets. However, there is little understanding of differences across multiple markets within a uniform macro context, or how they might vary between different types of NTFPs. Therefore, this study sought to determine the factors and rationale behind the setting of prices for selected NTFPs in 15 different areas of South Africa. The results showed that the pricing factors considered by sellers when setting the prices of NTFP varied with the type of NTFP being sold, type of market (home markets or urban markets) and the method used by the seller to procure the stock. Overall, transport costs, stock price, profit margin, time taken to collect or produce the product and market price were the widely used factors to determine prices for NTFPs. The marked variation in both markets and products show that there was no formal or certain price setting mechanism that was used by NTFP sellers establish the market prices of NTFPs, with price discovery being the most widespread.
- Full Text:
- Date Issued: 2018
Primary controls on iron and manganese distribution in sphalerite of the Gams Formation, Gamsberg zinc deposit, Namaqualand, South Africa
- Authors: Poignant-Molina, Léo
- Date: 2018
- Subjects: Sphalerite , Sphalerite South Africa Gamsberg , Manganese South Africa Gamsberg , Zinc mines and mining South Africa Gamsberg , Geochemistry South Africa Gamsberg , Metamorphism (Geology) , Electron probe microanalysis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63775 , vital:28488
- Description: The Gamsberg deposit is a 200 Mt zinc reserve belonging to the world class base metalrich Aggeneys-Gamsberg mining district. A rifting environment permitted the development of four proximal SEDEX-type deposits whereby Gamsberg is localized in the eastern side of the district and characterised by a peculiar enrichment in manganese. This study investigates the geochemistry of sphalerite in the Gams Formation holding the economic units of the deposit. Microscopic petrography revealed that most of primary textures have been overprinted by recrystallization, alteration, replacement and deformational textures produced during the polyphase metamorphism of the Namaquan Orogeny. Therefore, EPMA analysis provided the bulk of information to define the geochemical distribution of sphalerite. A lateral variation was noticed throughout the Gams Formation, whereby the North orebody presents Zn-rich and Fe+Mn-poor sphalerite while the West and East orebodies contain Zn-poor and Fe-Mn-rich sphalerite. This feature has been interpreted as the association of a chemocline and a variation in the basin topography defining deep Mn+Fe-rich zones and shallow Mn+Fe-poor zones in the primitive basin. It is suggested that mineralized hot brines mixed with seawater developed the chemocline. The uneven topography shaped the geochemical variation between the actual orebodies.
- Full Text:
- Date Issued: 2018
- Authors: Poignant-Molina, Léo
- Date: 2018
- Subjects: Sphalerite , Sphalerite South Africa Gamsberg , Manganese South Africa Gamsberg , Zinc mines and mining South Africa Gamsberg , Geochemistry South Africa Gamsberg , Metamorphism (Geology) , Electron probe microanalysis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63775 , vital:28488
- Description: The Gamsberg deposit is a 200 Mt zinc reserve belonging to the world class base metalrich Aggeneys-Gamsberg mining district. A rifting environment permitted the development of four proximal SEDEX-type deposits whereby Gamsberg is localized in the eastern side of the district and characterised by a peculiar enrichment in manganese. This study investigates the geochemistry of sphalerite in the Gams Formation holding the economic units of the deposit. Microscopic petrography revealed that most of primary textures have been overprinted by recrystallization, alteration, replacement and deformational textures produced during the polyphase metamorphism of the Namaquan Orogeny. Therefore, EPMA analysis provided the bulk of information to define the geochemical distribution of sphalerite. A lateral variation was noticed throughout the Gams Formation, whereby the North orebody presents Zn-rich and Fe+Mn-poor sphalerite while the West and East orebodies contain Zn-poor and Fe-Mn-rich sphalerite. This feature has been interpreted as the association of a chemocline and a variation in the basin topography defining deep Mn+Fe-rich zones and shallow Mn+Fe-poor zones in the primitive basin. It is suggested that mineralized hot brines mixed with seawater developed the chemocline. The uneven topography shaped the geochemical variation between the actual orebodies.
- Full Text:
- Date Issued: 2018
Pro-Environmental behaviour in student residences at Rhodes University, South Africa:
- Thondhlana, Gladman, Hlatshwayo, Thina N
- Authors: Thondhlana, Gladman , Hlatshwayo, Thina N
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144288 , vital:38328 , https://doi.org/10.3390/su10082746
- Description: Human behaviour is at the centre of most environmental problems; hence, the promotion of pro-environmental behaviour is considered to be a pathway towards sustainability. Despite the availability of insights gained from pro-environmental behaviour studies, mainly from household and workplace settings, a key question remains—can these insights be applied in university residence settings? Within university campuses, student residences are a major entity in sustainability debates because they are major consumers of resources including paper, water and energy with severe repercussions for university budgets and the environment. Using a questionnaire survey, this study explores reported pro-environmental behaviour and its determinants at Rhodes University, South Africa. Data were analysed using descriptive and inferential statistics where relevant. The findings show a high level of heterogeneity in reported pro-environmental behaviour, attributed to a suite of internal and external factors. Internal dispositional factors seemed to constrain students from acting pro-environmentally. This study highlights the need to encourage environmental behaviour in university residence settings by supporting the antecedents of and getting rid of barriers to pro-environmental actions.
- Full Text:
- Date Issued: 2018
- Authors: Thondhlana, Gladman , Hlatshwayo, Thina N
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144288 , vital:38328 , https://doi.org/10.3390/su10082746
- Description: Human behaviour is at the centre of most environmental problems; hence, the promotion of pro-environmental behaviour is considered to be a pathway towards sustainability. Despite the availability of insights gained from pro-environmental behaviour studies, mainly from household and workplace settings, a key question remains—can these insights be applied in university residence settings? Within university campuses, student residences are a major entity in sustainability debates because they are major consumers of resources including paper, water and energy with severe repercussions for university budgets and the environment. Using a questionnaire survey, this study explores reported pro-environmental behaviour and its determinants at Rhodes University, South Africa. Data were analysed using descriptive and inferential statistics where relevant. The findings show a high level of heterogeneity in reported pro-environmental behaviour, attributed to a suite of internal and external factors. Internal dispositional factors seemed to constrain students from acting pro-environmentally. This study highlights the need to encourage environmental behaviour in university residence settings by supporting the antecedents of and getting rid of barriers to pro-environmental actions.
- Full Text:
- Date Issued: 2018
Production, purification, and characterisation of proteases from an ericoid mycorrhizal fungus, Oidiodendron maius
- Authors: Manyumwa, Colleen Varaidzo
- Date: 2018
- Subjects: Ascomycetes , Mycorrhizal fungi , Ericaceae , Proteolytic enzymes , Silver Recycling
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/62833 , vital:28298
- Description: The aim of this study was to produce, purify and characterise proteases from the ericoid mycorrhizal fungus, Oidiodendron maius (CafRU082b/KP119480), as well as to explore their potential application in the recovery of silver from X-ray film. Firstly, the growth of the ericoid mycorrhizal fungus, Oidiodendron maius (CafRU082b), was studied, and its ability to produce proteolytic enzymes was investigated. O. maius proved to grow well in the dark, submerged in Modified Melin Norkran’s liquid medium at a pH of 5 and at 25°C. Pure cultures of the fungus were maintained on Potato Dextrose Agar (PDA). The fungus grew on PDA plates containing different substrates including haemoglobin, casein, gelatin as well as azocasein. Zones of clearance, however, were only observed on plates containing gelatin after treatment with mercuric chloride, HgCl2. Proteases were successfully produced after 14 days when gelatin was incorporated into the growth medium. After production of the proteases, purification and characterisation of the enzymes was performed. Purification of the enzymes was performed by acetone precipitation followed by ultrafiltration with 50 kDa and 30 kDa cut off membrane filters. A final purification fold of approximately 37.6 was achieved. Unusual yields of above 100% were observed after each purification step with the final yield achieved being 196% with a final specific activity of 2707 U/mg. SDS-PAGE revealed a protease band of 35 kDa which was also visible on the zymogram at approximately 36 kDa. The zymogram showed clear hydrolysis bands against a blue background after staining with Coomassie Brilliant Blue. Physico-chemical characterisation of the protease revealed its pH optimum to be pH 3.0 and its temperature optimum 68°C. Another peak was observed on the pH profile at pH 7.0. The protease exhibited high thermostability at temperatures 37°C, 80°C as well as 100°C with the enzyme retaining close to 50% of its initial activity after 4 h of exposure to all three temperatures. All ions tested for their effects on the proteases, except Ca2+, enhanced protease activity. Ca2+ did not exhibit any significant effect on the enzyme’s activity while Zn2+ had the highest effect, enhancing enzyme activity by 305%. The proteases, however, were not significantly inhibited by EDTA, a metal chelating agent and a known metalloprotease inhibitor. The enzyme was classified as an aspartic protease due to complete inhibition by 25 μM of pepstatin A, coupled to its low pH optimum of 3.0. Addition of trans-Epoxysuccinyl-L-leucylamido-(4-guanidino)butane (E-64), a cysteine protease inhibitor, and 2-mercaptoethanol increased protease activity. The proteases exhibited a narrow substrate specificity towards gelatin and no other substrate. Substrate kinetics values were plotted on a Michaelis-Menten Graph and showed that the enzyme had a Vmax of 55.25 U/ml and a Km of 2.7 mg/ml gelatin. A low Km indicated that the protease had a high affinity for gelatin. Silver recovery studies from X-ray film revealed the proteases’ capability to remove silver from X-ray film, leaving the film intact. The recovery of silver was perceived visually, by film observation, as well as by scan electron microscopy (SEM) images, where clearance of the film was observed after incubation with the enzyme. Energy dispersive X-ray spectroscopy (EDS) profiles also confirmed removal of silver from the film, with a Ag peak showing on the profile of the film before treatment with the proteases and no peak after treatment. The crude protease sample was, however, catalytically more efficient compared to the partially purified sample. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2018
- Full Text:
- Date Issued: 2018
- Authors: Manyumwa, Colleen Varaidzo
- Date: 2018
- Subjects: Ascomycetes , Mycorrhizal fungi , Ericaceae , Proteolytic enzymes , Silver Recycling
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/62833 , vital:28298
- Description: The aim of this study was to produce, purify and characterise proteases from the ericoid mycorrhizal fungus, Oidiodendron maius (CafRU082b/KP119480), as well as to explore their potential application in the recovery of silver from X-ray film. Firstly, the growth of the ericoid mycorrhizal fungus, Oidiodendron maius (CafRU082b), was studied, and its ability to produce proteolytic enzymes was investigated. O. maius proved to grow well in the dark, submerged in Modified Melin Norkran’s liquid medium at a pH of 5 and at 25°C. Pure cultures of the fungus were maintained on Potato Dextrose Agar (PDA). The fungus grew on PDA plates containing different substrates including haemoglobin, casein, gelatin as well as azocasein. Zones of clearance, however, were only observed on plates containing gelatin after treatment with mercuric chloride, HgCl2. Proteases were successfully produced after 14 days when gelatin was incorporated into the growth medium. After production of the proteases, purification and characterisation of the enzymes was performed. Purification of the enzymes was performed by acetone precipitation followed by ultrafiltration with 50 kDa and 30 kDa cut off membrane filters. A final purification fold of approximately 37.6 was achieved. Unusual yields of above 100% were observed after each purification step with the final yield achieved being 196% with a final specific activity of 2707 U/mg. SDS-PAGE revealed a protease band of 35 kDa which was also visible on the zymogram at approximately 36 kDa. The zymogram showed clear hydrolysis bands against a blue background after staining with Coomassie Brilliant Blue. Physico-chemical characterisation of the protease revealed its pH optimum to be pH 3.0 and its temperature optimum 68°C. Another peak was observed on the pH profile at pH 7.0. The protease exhibited high thermostability at temperatures 37°C, 80°C as well as 100°C with the enzyme retaining close to 50% of its initial activity after 4 h of exposure to all three temperatures. All ions tested for their effects on the proteases, except Ca2+, enhanced protease activity. Ca2+ did not exhibit any significant effect on the enzyme’s activity while Zn2+ had the highest effect, enhancing enzyme activity by 305%. The proteases, however, were not significantly inhibited by EDTA, a metal chelating agent and a known metalloprotease inhibitor. The enzyme was classified as an aspartic protease due to complete inhibition by 25 μM of pepstatin A, coupled to its low pH optimum of 3.0. Addition of trans-Epoxysuccinyl-L-leucylamido-(4-guanidino)butane (E-64), a cysteine protease inhibitor, and 2-mercaptoethanol increased protease activity. The proteases exhibited a narrow substrate specificity towards gelatin and no other substrate. Substrate kinetics values were plotted on a Michaelis-Menten Graph and showed that the enzyme had a Vmax of 55.25 U/ml and a Km of 2.7 mg/ml gelatin. A low Km indicated that the protease had a high affinity for gelatin. Silver recovery studies from X-ray film revealed the proteases’ capability to remove silver from X-ray film, leaving the film intact. The recovery of silver was perceived visually, by film observation, as well as by scan electron microscopy (SEM) images, where clearance of the film was observed after incubation with the enzyme. Energy dispersive X-ray spectroscopy (EDS) profiles also confirmed removal of silver from the film, with a Ag peak showing on the profile of the film before treatment with the proteases and no peak after treatment. The crude protease sample was, however, catalytically more efficient compared to the partially purified sample. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2018
- Full Text:
- Date Issued: 2018
Project CrayOn: Back to the future for a more General-Purpose GPU
- Authors: Machanick, Philip
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439353 , vital:73569 , http://wp3workshop.website/pdfs/WP3_machanick.pdf
- Description: General purpose of use graphics processing units (GPGPU) recapitulates many of the lessons of the early generations of supercomputers. To what extent have we learnt those lessons, rather than repeating the mistakes? To answer that question, I review why the Cray-1 design ushered in a succession of successful supercomputer designs, while more exotic modes of parallelism failed to gain traction. In the light of this review, I propose that new packaging breakthroughs create an opening for revisiting our approach to GPUs and hence GPGPU. If we do not do so now, the GPU endpoint–when no GPU enhancement will be perceptible to human senses–will in any case remove the economic incentive to build ever-faster GPUs and hence the economy of scale incentive for GPGPU. Anticipating this change now makes sense when new 3D packaging options are opening up; I propose one such option inspired by packaging of the Cray-1.
- Full Text:
- Date Issued: 2018
- Authors: Machanick, Philip
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439353 , vital:73569 , http://wp3workshop.website/pdfs/WP3_machanick.pdf
- Description: General purpose of use graphics processing units (GPGPU) recapitulates many of the lessons of the early generations of supercomputers. To what extent have we learnt those lessons, rather than repeating the mistakes? To answer that question, I review why the Cray-1 design ushered in a succession of successful supercomputer designs, while more exotic modes of parallelism failed to gain traction. In the light of this review, I propose that new packaging breakthroughs create an opening for revisiting our approach to GPUs and hence GPGPU. If we do not do so now, the GPU endpoint–when no GPU enhancement will be perceptible to human senses–will in any case remove the economic incentive to build ever-faster GPUs and hence the economy of scale incentive for GPGPU. Anticipating this change now makes sense when new 3D packaging options are opening up; I propose one such option inspired by packaging of the Cray-1.
- Full Text:
- Date Issued: 2018
Prospects for biological control of cactus weeds in Namibia
- Paterson, Iain D, Manheimmer, C A, Zimmermann, H C
- Authors: Paterson, Iain D , Manheimmer, C A , Zimmermann, H C
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417522 , vital:71460 , xlink:href="https://doi.org/10.1080/09583157.2018.1562040"
- Description: Australia and South Africa have a long history of sharing successful biocontrol agents for cactus weeds but other countries, such as Namibia, could also benefit. There are four biological control agents that are widely utilised in South Africa and/or Australia for the control of 10 invasive alien Cactaceae in Namibia.
- Full Text:
- Date Issued: 2018
- Authors: Paterson, Iain D , Manheimmer, C A , Zimmermann, H C
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417522 , vital:71460 , xlink:href="https://doi.org/10.1080/09583157.2018.1562040"
- Description: Australia and South Africa have a long history of sharing successful biocontrol agents for cactus weeds but other countries, such as Namibia, could also benefit. There are four biological control agents that are widely utilised in South Africa and/or Australia for the control of 10 invasive alien Cactaceae in Namibia.
- Full Text:
- Date Issued: 2018
Protection of internally displaced persons in Kenya under the Prevention, Protection and Assistance to Internally Displaced Persons and Affected Communities Act of 2012: an appraisal
- Authors: Juma, Laurence
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126122 , vital:35851 , https://hdl.handle.net/10520/EJC-107c9cba58
- Description: This article discusses Kenya’s Prevention, Protection and Assistance to Internally Displaced Persons and Affected Communities Act of 2012, which is among the very few national legislations globally that addresses the plight of internally displaced persons. While it records the momentous achievement in creating a viable and legally enforceable legislative framework for the protection of IDPs, the article highlights some of the areas that could be improved for the Act to realise its promise. It notes for example the inchoate manner in which institutions are created and the lack of resources. The article while isolating these challenges also suggests numerous ways in which such challenges can be overcome. It underscores the need for harmonised legal regimes, improvement of data collection and proper monitoring programmes, all which can be achieved and strengthened by a supportive political establishment as well as strategic amendments to various provisions of the Act.
- Full Text: false
- Date Issued: 2018
- Authors: Juma, Laurence
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126122 , vital:35851 , https://hdl.handle.net/10520/EJC-107c9cba58
- Description: This article discusses Kenya’s Prevention, Protection and Assistance to Internally Displaced Persons and Affected Communities Act of 2012, which is among the very few national legislations globally that addresses the plight of internally displaced persons. While it records the momentous achievement in creating a viable and legally enforceable legislative framework for the protection of IDPs, the article highlights some of the areas that could be improved for the Act to realise its promise. It notes for example the inchoate manner in which institutions are created and the lack of resources. The article while isolating these challenges also suggests numerous ways in which such challenges can be overcome. It underscores the need for harmonised legal regimes, improvement of data collection and proper monitoring programmes, all which can be achieved and strengthened by a supportive political establishment as well as strategic amendments to various provisions of the Act.
- Full Text: false
- Date Issued: 2018
Protection of rights of urban refugees in Kenya: revisiting Kituo Cha Sheria v The Attorney General
- Authors: Juma, Laurence
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125174 , vital:35740 , DOI: 10.25159/2522-6800/3291
- Description: This article discusses the judgment in the landmark case of Kituo Cha Sheria and Others v Attorney General in the light of the emerging rights jurisprudence in the area of refugee rights. It also explores the impact the judgment could have on the articulation of the rights of urban refugees in Kenya. Based on the assumption that Kenya’s 2010 Constitution provides an opportunity for the robust enforcement of rights, the article analyses the key rights and protection imperatives that were at the centre of the dispute. These include the right to dignity, freedom of movement and to work, and also the principle of refoulement. These rights are at the core of the protection agenda for urban refugees.
- Full Text: false
- Date Issued: 2018
- Authors: Juma, Laurence
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125174 , vital:35740 , DOI: 10.25159/2522-6800/3291
- Description: This article discusses the judgment in the landmark case of Kituo Cha Sheria and Others v Attorney General in the light of the emerging rights jurisprudence in the area of refugee rights. It also explores the impact the judgment could have on the articulation of the rights of urban refugees in Kenya. Based on the assumption that Kenya’s 2010 Constitution provides an opportunity for the robust enforcement of rights, the article analyses the key rights and protection imperatives that were at the centre of the dispute. These include the right to dignity, freedom of movement and to work, and also the principle of refoulement. These rights are at the core of the protection agenda for urban refugees.
- Full Text: false
- Date Issued: 2018
Purification and characterization of an amyloglucosidase from an ericoid mycorrhizal fungus (Leohumicola incrustata)
- Adeoyo, Olusegun R, Pletschke, Brett I, Dames, Joanna F
- Authors: Adeoyo, Olusegun R , Pletschke, Brett I , Dames, Joanna F
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440405 , vital:73780 , https://doi.org/10.1186/s13568-018-0685-1
- Description: This study aimed to purify and characterize amyloglucosidase (AMG) from Leohumicola incrustata. AMG was purified to homogeneity from cell-free culture filtrate of an ERM fungus grown in a modified Melin–Norkrans liquid medium. The molecular mass of the AMG was estimated to be 101 kDa by combining the results of Sephadex G-100 gel filtration, sodium dodecyl sulphate–polyacrylamide gel electrophoresis, and zymography. The Km and kcat values were 0.38 mg mL−1 and 70 s−1, respectively, using soluble starch as a substrate. The enzyme was stable at 45 °C (pH 5.0), retaining over 65% activity after a pre-incubation period of 24 h. The metal inhibition profile of the AMG showed that Mn2+ and Ca2+ enhanced activity, while it was stable to metals ions, except a few (Al3+, Co2+, Hg2+ and Cd2+) that were inhibitory at a concentration higher than 5 mM. Thin layer chromatography revealed that only glucose was produced as the product of starch hydrolysis. The amylase from L. incrustata is a glucoamylase with promising characteristics such as temperature stability over an extended period, high substrate affinity and stability to a range of chemicals. Also, this study reports for the first time the possibility of using some culturable ERM fungi to produce enzymes for the bio-economy.
- Full Text:
- Date Issued: 2018
- Authors: Adeoyo, Olusegun R , Pletschke, Brett I , Dames, Joanna F
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440405 , vital:73780 , https://doi.org/10.1186/s13568-018-0685-1
- Description: This study aimed to purify and characterize amyloglucosidase (AMG) from Leohumicola incrustata. AMG was purified to homogeneity from cell-free culture filtrate of an ERM fungus grown in a modified Melin–Norkrans liquid medium. The molecular mass of the AMG was estimated to be 101 kDa by combining the results of Sephadex G-100 gel filtration, sodium dodecyl sulphate–polyacrylamide gel electrophoresis, and zymography. The Km and kcat values were 0.38 mg mL−1 and 70 s−1, respectively, using soluble starch as a substrate. The enzyme was stable at 45 °C (pH 5.0), retaining over 65% activity after a pre-incubation period of 24 h. The metal inhibition profile of the AMG showed that Mn2+ and Ca2+ enhanced activity, while it was stable to metals ions, except a few (Al3+, Co2+, Hg2+ and Cd2+) that were inhibitory at a concentration higher than 5 mM. Thin layer chromatography revealed that only glucose was produced as the product of starch hydrolysis. The amylase from L. incrustata is a glucoamylase with promising characteristics such as temperature stability over an extended period, high substrate affinity and stability to a range of chemicals. Also, this study reports for the first time the possibility of using some culturable ERM fungi to produce enzymes for the bio-economy.
- Full Text:
- Date Issued: 2018
Pursuing cost-effective secure network micro-segmentation
- Authors: Fürst, Mark Richard
- Date: 2018
- Subjects: Computer networks -- Security measures , Computer networks -- Access control , Firewalls (Computer security) , IPSec (Computer network protocol) , Network micro-segmentation
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/131106 , vital:36524
- Description: Traditional network segmentation allows discrete trust levels to be defined for different network segments, using physical firewalls or routers that control north-south traffic flowing between different interfaces. This technique reduces the attack surface area should an attacker breach one of the perimeter defences. However, east-west traffic flowing between endpoints within the same network segment does not pass through a firewall, and an attacker may be able to move laterally between endpoints within that segment. Network micro-segmentation was designed to address the challenge of controlling east-west traffic, and various solutions have been released with differing levels of capabilities and feature sets. These approaches range from simple network switch Access Control List based segmentation to complex hypervisor based software-defined security segments defined down to the individual workload, container or process level, and enforced via policy based security controls for each segment. Several commercial solutions for network micro-segmentation exist, but these are primarily focused on physical and cloud data centres, and are often accompanied by significant capital outlay and resource requirements. Given these constraints, this research determines whether existing tools provided with operating systems can be re-purposed to implement micro-segmentation and restrict east-west traffic within one or more network segments for a small-to-medium sized corporate network. To this end, a proof-of-concept lab environment was built with a heterogeneous mix of Windows and Linux virtual servers and workstations deployed in an Active Directory domain. The use of Group Policy Objects to deploy IPsec Server and Domain Isolation for controlling traffic between endpoints is examined, in conjunction with IPsec Authenticated Header and Encapsulating Security Payload modes as an additional layer of security. The outcome of the research shows that revisiting existing tools can enable organisations to implement an additional, cost-effective secure layer of defence in their network.
- Full Text:
- Date Issued: 2018
- Authors: Fürst, Mark Richard
- Date: 2018
- Subjects: Computer networks -- Security measures , Computer networks -- Access control , Firewalls (Computer security) , IPSec (Computer network protocol) , Network micro-segmentation
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/131106 , vital:36524
- Description: Traditional network segmentation allows discrete trust levels to be defined for different network segments, using physical firewalls or routers that control north-south traffic flowing between different interfaces. This technique reduces the attack surface area should an attacker breach one of the perimeter defences. However, east-west traffic flowing between endpoints within the same network segment does not pass through a firewall, and an attacker may be able to move laterally between endpoints within that segment. Network micro-segmentation was designed to address the challenge of controlling east-west traffic, and various solutions have been released with differing levels of capabilities and feature sets. These approaches range from simple network switch Access Control List based segmentation to complex hypervisor based software-defined security segments defined down to the individual workload, container or process level, and enforced via policy based security controls for each segment. Several commercial solutions for network micro-segmentation exist, but these are primarily focused on physical and cloud data centres, and are often accompanied by significant capital outlay and resource requirements. Given these constraints, this research determines whether existing tools provided with operating systems can be re-purposed to implement micro-segmentation and restrict east-west traffic within one or more network segments for a small-to-medium sized corporate network. To this end, a proof-of-concept lab environment was built with a heterogeneous mix of Windows and Linux virtual servers and workstations deployed in an Active Directory domain. The use of Group Policy Objects to deploy IPsec Server and Domain Isolation for controlling traffic between endpoints is examined, in conjunction with IPsec Authenticated Header and Encapsulating Security Payload modes as an additional layer of security. The outcome of the research shows that revisiting existing tools can enable organisations to implement an additional, cost-effective secure layer of defence in their network.
- Full Text:
- Date Issued: 2018
Pyridone substituted phthalocyanines: Photophysico-chemical properties and TD-DFT calculations
- Abdurrahmanoğlu, Şaziye, Canlica, Mevlüde, Mack, John, Nyokong, Tebello
- Authors: Abdurrahmanoğlu, Şaziye , Canlica, Mevlüde , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188216 , vital:44735 , xlink:href="https://doi.org/10.1142/S1088424617500730"
- Description: 4-(6-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yloxy)phthalonitrile has been used to prepare a novel Zn(II) phthalocyanines with four peripheral pyridone substituents. The compound has been characterized by UV-visible absorption, FT-IR and 11H-NMR spectroscopy, elemental analysis and MALDI-TOF mass spectroscopy. The fluorescence, triplet quantum and singlet oxygen quantum yields have been determined and TD-DFT calculations have been used to identify trends in the electronic structure.
- Full Text:
- Date Issued: 2018
- Authors: Abdurrahmanoğlu, Şaziye , Canlica, Mevlüde , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188216 , vital:44735 , xlink:href="https://doi.org/10.1142/S1088424617500730"
- Description: 4-(6-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yloxy)phthalonitrile has been used to prepare a novel Zn(II) phthalocyanines with four peripheral pyridone substituents. The compound has been characterized by UV-visible absorption, FT-IR and 11H-NMR spectroscopy, elemental analysis and MALDI-TOF mass spectroscopy. The fluorescence, triplet quantum and singlet oxygen quantum yields have been determined and TD-DFT calculations have been used to identify trends in the electronic structure.
- Full Text:
- Date Issued: 2018
Quantification of pre-competitive sleep/wake behaviour in a sample of South African cyclists
- Authors: Steenekamp, Travis
- Date: 2018
- Subjects: Sleep deprivation , Cyclists Health and hygiene South Africa , Sleep Physiological aspects , Performance , Performance anxiety
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/59015 , vital:27408
- Description: The quantification of athlete pre-competitive sleep behaviour is of interest owing to the possibility that sleep loss may have a negative effect on health and performance. The purpose of this study was to monitor and quantify the sleep/wake patterns of South African cyclists prior to competitive races. A total of 336 cyclists, male and female and of differing competition levels, cycling in either the 2015 Tsogo Sun Amashova or the 2016 Telkom 94.7 Cycle Challenge completed an altered version of the Competitive Sports and Sleep Questionnaire. The questionnaire asked cyclists to report on precompetitive sleep over the past year. A subset of 92 cyclists also recorded a Core Consensus Sleep Diary for the three nights leading up to the races. The questionnaire showed that 67% of the cyclists reported worsened sleep at least once prior to competition within the past 12 months. The sleep diary found that the cyclists’ average sleep duration the night before the races was 6h19min (±1h38min), which was significantly less than two and three nights prior to the races. Sleep quality was also shown to deteriorate significantly the night before the races. The contributing factors leading to worsened pre-competitive sleep were the time the cyclists had to wake-up as well as perceived increases in sleep latency and awakenings after sleep onset. Anxiety was found to be the major cause of sleep disturbances. While females were found to be significantly more likely to report having experienced poorer sleep before competition in the past year, the sleep diary showed no difference in sleep the night before the races between the sexes. Females were significantly more likely to report instances of unpleasant dreams and waking up during the night. Again, the sleep diary data did not corroborate these findings. Females were also found to report significantly more accounts of nervousness or thoughts about competition as being the cause of sleep problems. There was no difference in sleep loss the night before competition when comparing competition-level groups. The only significant difference was that recreational cyclists were more likely to report sleeping in foreign environments as a cause of sleep disturbances. Despite a large percentage of cyclists experiencing pre-competitive sleep loss, over half (55%) perceived sleep loss to have no impact on their performance. Analysis of pre-sleep behaviour also revealed that the cyclists engaged in several practices that may have a negative effect on subsequent sleep. The vast majority of the cyclists (61%) indicated having no specific strategy to help them sleep the night before competition. Fifteen percent of cyclists reporting using media devices to help them fall asleep, a practice that has been shown to disrupt sleep. In conclusion, most cyclists, regardless of sex and level of competition experience precompetitive sleep loss attributed largely to anxiety but with the perception that this loss in sleep does not negatively impact their performance.
- Full Text:
- Date Issued: 2018
- Authors: Steenekamp, Travis
- Date: 2018
- Subjects: Sleep deprivation , Cyclists Health and hygiene South Africa , Sleep Physiological aspects , Performance , Performance anxiety
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/59015 , vital:27408
- Description: The quantification of athlete pre-competitive sleep behaviour is of interest owing to the possibility that sleep loss may have a negative effect on health and performance. The purpose of this study was to monitor and quantify the sleep/wake patterns of South African cyclists prior to competitive races. A total of 336 cyclists, male and female and of differing competition levels, cycling in either the 2015 Tsogo Sun Amashova or the 2016 Telkom 94.7 Cycle Challenge completed an altered version of the Competitive Sports and Sleep Questionnaire. The questionnaire asked cyclists to report on precompetitive sleep over the past year. A subset of 92 cyclists also recorded a Core Consensus Sleep Diary for the three nights leading up to the races. The questionnaire showed that 67% of the cyclists reported worsened sleep at least once prior to competition within the past 12 months. The sleep diary found that the cyclists’ average sleep duration the night before the races was 6h19min (±1h38min), which was significantly less than two and three nights prior to the races. Sleep quality was also shown to deteriorate significantly the night before the races. The contributing factors leading to worsened pre-competitive sleep were the time the cyclists had to wake-up as well as perceived increases in sleep latency and awakenings after sleep onset. Anxiety was found to be the major cause of sleep disturbances. While females were found to be significantly more likely to report having experienced poorer sleep before competition in the past year, the sleep diary showed no difference in sleep the night before the races between the sexes. Females were significantly more likely to report instances of unpleasant dreams and waking up during the night. Again, the sleep diary data did not corroborate these findings. Females were also found to report significantly more accounts of nervousness or thoughts about competition as being the cause of sleep problems. There was no difference in sleep loss the night before competition when comparing competition-level groups. The only significant difference was that recreational cyclists were more likely to report sleeping in foreign environments as a cause of sleep disturbances. Despite a large percentage of cyclists experiencing pre-competitive sleep loss, over half (55%) perceived sleep loss to have no impact on their performance. Analysis of pre-sleep behaviour also revealed that the cyclists engaged in several practices that may have a negative effect on subsequent sleep. The vast majority of the cyclists (61%) indicated having no specific strategy to help them sleep the night before competition. Fifteen percent of cyclists reporting using media devices to help them fall asleep, a practice that has been shown to disrupt sleep. In conclusion, most cyclists, regardless of sex and level of competition experience precompetitive sleep loss attributed largely to anxiety but with the perception that this loss in sleep does not negatively impact their performance.
- Full Text:
- Date Issued: 2018