Gaining cyber security insight through an analysis of open source intelligence data: an East African case study
- Authors: Chindipha, Stones Dalitso
- Date: 2018
- Subjects: Open source intelligence -- Africa, East , Computer security -- Africa, East , Computer networks -- Security measures -- Africa, East , Denial of service attacks -- Africa, East , Sentient Hvper-Optimised Data Access Network (SHODAN) , Internet Background Radiation (IBR)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60618 , vital:27805
- Description: With each passing year the number of Internet users and connected devices grows, and this is particularly so in Africa. This growth brings with it an increase in the prevalence cyber-attacks. Looking at the current state of affairs, cybersecurity incidents are more likely to increase in African countries mainly due to the increased prevalence and affordability of broadband connectivity which is coupled with lack of online security awareness. The adoption of mobile banking has aggravated the situation making the continent more attractive to hackers who bank on the malpractices of users. Using Open Source Intelligence (OSINT) data sources like Sentient Hvper-Optimised Data Access Network (SHODAN) and Internet Background Radiation (IBR), this research explores the prevalence of vulnerabilities and their accessibility to evber threat actors. The research focuses on the East African Community (EAC) comprising of Tanzania, Kenya, Malawi, and Uganda, An IBR data set collected by a Rhodes University network telescope spanning over 72 months was used in this research, along with two snapshot period of data from the SHODAN project. The findings shows that there is a significant risk to systems within the EAC, particularly using the SHODAN data. The MITRE CVSS threat scoring system was applied to this research using FREAK and Heartbleed as sample vulnerabilities identified in EAC, When looking at IBR, the research has shown that attackers can use either destination ports or IP source addresses to perform an attack which if not attended to may be reused yearly until later on move to the allocated IP address space once it starts making random probes. The moment it finds one vulnerable client on the network it spreads throughout like a worm, DDoS is one the attacks that can be generated from IBR, Since the SHODAN dataset had two collection points, the study has shown the changes that have occurred in Malawi and Tanzania for a period of 14 months by using three variables i.e, device type, operating systems, and ports. The research has also identified vulnerable devices in all the four countries. Apart from that, the study identified operating systems, products, OpenSSL, ports and ISPs as some of the variables that can be used to identify vulnerabilities in systems. In the ease of OpenSSL and products, this research went further by identifying the type of attack that can occur and its associated CVE-ID.
- Full Text:
- Date Issued: 2018
- Authors: Chindipha, Stones Dalitso
- Date: 2018
- Subjects: Open source intelligence -- Africa, East , Computer security -- Africa, East , Computer networks -- Security measures -- Africa, East , Denial of service attacks -- Africa, East , Sentient Hvper-Optimised Data Access Network (SHODAN) , Internet Background Radiation (IBR)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60618 , vital:27805
- Description: With each passing year the number of Internet users and connected devices grows, and this is particularly so in Africa. This growth brings with it an increase in the prevalence cyber-attacks. Looking at the current state of affairs, cybersecurity incidents are more likely to increase in African countries mainly due to the increased prevalence and affordability of broadband connectivity which is coupled with lack of online security awareness. The adoption of mobile banking has aggravated the situation making the continent more attractive to hackers who bank on the malpractices of users. Using Open Source Intelligence (OSINT) data sources like Sentient Hvper-Optimised Data Access Network (SHODAN) and Internet Background Radiation (IBR), this research explores the prevalence of vulnerabilities and their accessibility to evber threat actors. The research focuses on the East African Community (EAC) comprising of Tanzania, Kenya, Malawi, and Uganda, An IBR data set collected by a Rhodes University network telescope spanning over 72 months was used in this research, along with two snapshot period of data from the SHODAN project. The findings shows that there is a significant risk to systems within the EAC, particularly using the SHODAN data. The MITRE CVSS threat scoring system was applied to this research using FREAK and Heartbleed as sample vulnerabilities identified in EAC, When looking at IBR, the research has shown that attackers can use either destination ports or IP source addresses to perform an attack which if not attended to may be reused yearly until later on move to the allocated IP address space once it starts making random probes. The moment it finds one vulnerable client on the network it spreads throughout like a worm, DDoS is one the attacks that can be generated from IBR, Since the SHODAN dataset had two collection points, the study has shown the changes that have occurred in Malawi and Tanzania for a period of 14 months by using three variables i.e, device type, operating systems, and ports. The research has also identified vulnerable devices in all the four countries. Apart from that, the study identified operating systems, products, OpenSSL, ports and ISPs as some of the variables that can be used to identify vulnerabilities in systems. In the ease of OpenSSL and products, this research went further by identifying the type of attack that can occur and its associated CVE-ID.
- Full Text:
- Date Issued: 2018
Gender and popular imaginaries in Africa:
- Spencer, Lynda G, Ligaga, Dina, Musila, Grace
- Authors: Spencer, Lynda G , Ligaga, Dina , Musila, Grace
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/138860 , vital:37679 , DOI: 10.1080/10130950.2018.1526467
- Description: If we accept that many Africans’ social perceptions on a range of questions, including gender, are shaped by popular cultural productions which retain a keen pulse on the everyday, then it is important to reflect on the interface between gender and popular imaginaries. The debate on the definition of the ‘popular’ remains an open one with multiple interpretations and categories. This contestation in itself gestures towards popular culture’s inclination for ambiguity and slipperiness. As Karin Barber (2018:13) reminds us, the popular constitutes “expressive forms that are constantly emergent, ephemeral, embedded in daily life, given to extraordinary bursts of activity and rapid transformation”. For George Ogola, popular cultural forms “engage with and subject the polity to constant critique through informal but widely recognised forms of censure” (2017:2). In this special issue, we use popular imaginaries to mean the range of cultural productions, platforms, and interactions between consumers and producers - which are often interchangeable - that capture the material, the affective, as inflected and refracted in different texts, contexts and platforms.
- Full Text:
- Date Issued: 2018
- Authors: Spencer, Lynda G , Ligaga, Dina , Musila, Grace
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/138860 , vital:37679 , DOI: 10.1080/10130950.2018.1526467
- Description: If we accept that many Africans’ social perceptions on a range of questions, including gender, are shaped by popular cultural productions which retain a keen pulse on the everyday, then it is important to reflect on the interface between gender and popular imaginaries. The debate on the definition of the ‘popular’ remains an open one with multiple interpretations and categories. This contestation in itself gestures towards popular culture’s inclination for ambiguity and slipperiness. As Karin Barber (2018:13) reminds us, the popular constitutes “expressive forms that are constantly emergent, ephemeral, embedded in daily life, given to extraordinary bursts of activity and rapid transformation”. For George Ogola, popular cultural forms “engage with and subject the polity to constant critique through informal but widely recognised forms of censure” (2017:2). In this special issue, we use popular imaginaries to mean the range of cultural productions, platforms, and interactions between consumers and producers - which are often interchangeable - that capture the material, the affective, as inflected and refracted in different texts, contexts and platforms.
- Full Text:
- Date Issued: 2018
Gender equity in land tenure : an assessment of the challenges faced by women in the communal land tenure system in Keiskammahoek, South Africa
- Authors: Sonkosi, Abongile
- Date: 2018
- Subjects: Land tenure--South Africa--Eastern Cape Land use--South Africa--Eastern Cape Land tenure
- Language: English
- Type: Thesis , Masters , Rural Development
- Identifier: http://hdl.handle.net/10353/17138 , vital:40859
- Description: Despite the importance of land to women, women however are still deprived of security of tenure as a result of the gender biased laws which at their best only protect married women and at their worst fail to protect the rights of single, widowed and divorced women. An analysis of the land reform policies in South Africa as a whole on the issue of the advancement of women through land reform reveals a number of irregularities and false promises. Many of the new policy shifts are problematic as they tend to benefit the elite and continue to leave the majority of the rural poor people particularly women in communal areas with insecure land tenure. This research study examined: 1. the nature of land relations at work in Keiskammahoek and how they impact women’s rights to land. 2. How women in Keiskammahoek view their rights to land. 3. The challenges experienced and progress made by women in claiming their land rights in Keiskamahoek. Despite the importance of land to women, women however are still deprived of security of tenure as a result of the gender biased laws which at their best only protect married women and at their worst fail to protect the rights of single, widowed and divorced women. An analysis of the land reform policies in South Africa as a whole on the issue of the advancement of women through land reform reveals a number of irregularities and false promises. Many of the new policy shifts are problematic as they tend to benefit the elite and continue to leave the majority of the rural poor people particularly women in communal areas with insecure land tenure. This research study examined: 1. the nature of land relations at work in Keiskammahoek and how they impact women’s rights to land. 2. How women in Keiskammahoek view their rights to land. 3. The challenges experienced and progress made by women in claiming their land rights in Keiskamahoek. ownership in their communities. They expressed strong views against the suppression of their voice due to patriarchal structures that govern the way they live. They further observed that a woman’s voice in the rural communities generally does not get heard and that even if women get into positions of power they fail to stand up against women’s marginalization and gender inequalities. However, the most positive finding is that the wind of change is blowing in Keiskammahoek as different categories of women - married, single, divorced, widowed etc. begin to access residential and to some limited degree, agricultural plots. They appeal to the government to support them in accessing agricultural tools including tractors, irrigation systems, seeds etc. Although the progress made so far with regard to women’s access to land is acknowledged, a great deal of work still needs to be done in order to empower women through land reform. The study makes recommendations on the implementation of land tenure policy that addresses women’s challenges in land access and ownership.
- Full Text:
- Date Issued: 2018
- Authors: Sonkosi, Abongile
- Date: 2018
- Subjects: Land tenure--South Africa--Eastern Cape Land use--South Africa--Eastern Cape Land tenure
- Language: English
- Type: Thesis , Masters , Rural Development
- Identifier: http://hdl.handle.net/10353/17138 , vital:40859
- Description: Despite the importance of land to women, women however are still deprived of security of tenure as a result of the gender biased laws which at their best only protect married women and at their worst fail to protect the rights of single, widowed and divorced women. An analysis of the land reform policies in South Africa as a whole on the issue of the advancement of women through land reform reveals a number of irregularities and false promises. Many of the new policy shifts are problematic as they tend to benefit the elite and continue to leave the majority of the rural poor people particularly women in communal areas with insecure land tenure. This research study examined: 1. the nature of land relations at work in Keiskammahoek and how they impact women’s rights to land. 2. How women in Keiskammahoek view their rights to land. 3. The challenges experienced and progress made by women in claiming their land rights in Keiskamahoek. Despite the importance of land to women, women however are still deprived of security of tenure as a result of the gender biased laws which at their best only protect married women and at their worst fail to protect the rights of single, widowed and divorced women. An analysis of the land reform policies in South Africa as a whole on the issue of the advancement of women through land reform reveals a number of irregularities and false promises. Many of the new policy shifts are problematic as they tend to benefit the elite and continue to leave the majority of the rural poor people particularly women in communal areas with insecure land tenure. This research study examined: 1. the nature of land relations at work in Keiskammahoek and how they impact women’s rights to land. 2. How women in Keiskammahoek view their rights to land. 3. The challenges experienced and progress made by women in claiming their land rights in Keiskamahoek. ownership in their communities. They expressed strong views against the suppression of their voice due to patriarchal structures that govern the way they live. They further observed that a woman’s voice in the rural communities generally does not get heard and that even if women get into positions of power they fail to stand up against women’s marginalization and gender inequalities. However, the most positive finding is that the wind of change is blowing in Keiskammahoek as different categories of women - married, single, divorced, widowed etc. begin to access residential and to some limited degree, agricultural plots. They appeal to the government to support them in accessing agricultural tools including tractors, irrigation systems, seeds etc. Although the progress made so far with regard to women’s access to land is acknowledged, a great deal of work still needs to be done in order to empower women through land reform. The study makes recommendations on the implementation of land tenure policy that addresses women’s challenges in land access and ownership.
- Full Text:
- Date Issued: 2018
Gender mainstreaming in local governance: a case of O.R. Tambo District Municipality
- Authors: Mongoato, Boiketlo
- Date: 2018
- Subjects: Women in development -- South Africa -- Eastern Cape , Women -- Political activity -- South Africa -- Eastern Cape Local government -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: http://hdl.handle.net/10948/32334 , vital:32024
- Description: The purpose of this study is to establish the extent to which the OR Tambo District Municipality is able to implement gender mainstreaming to eliminate gender bias in governance and service delivery in order to improve the lives of the women in the district and to develop the community. This study is specifically concerned with the effect of leadership and staff capacity on the implementation of gender mainstreaming. The study was aimed at improving how the local government approaches gender mainstreaming and shed light on how it can be used as an all-inclusive developmental strategy. The data for this study were collected through document analysis and purposively selected in-depth interviews. The subjects of the study were selected from strategic units within the municipality which were identified to be the key stakeholders in gender mainstreaming in terms of the institutional arrangements. The results illustrate that despite a commitment to gender mainstreaming in the OR Tambo District Municipality, the institution still faces many challenges in its implementation. These challenges are linked to the absence of an institutional gender mainstreaming policy, poor understanding of gender mainstreaming and sectoral institutional arrangements that hinder the process of implementation. The data confirmed that a lack of skilled human resources hinders the implementation of gender mainstreaming.
- Full Text:
- Date Issued: 2018
- Authors: Mongoato, Boiketlo
- Date: 2018
- Subjects: Women in development -- South Africa -- Eastern Cape , Women -- Political activity -- South Africa -- Eastern Cape Local government -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: http://hdl.handle.net/10948/32334 , vital:32024
- Description: The purpose of this study is to establish the extent to which the OR Tambo District Municipality is able to implement gender mainstreaming to eliminate gender bias in governance and service delivery in order to improve the lives of the women in the district and to develop the community. This study is specifically concerned with the effect of leadership and staff capacity on the implementation of gender mainstreaming. The study was aimed at improving how the local government approaches gender mainstreaming and shed light on how it can be used as an all-inclusive developmental strategy. The data for this study were collected through document analysis and purposively selected in-depth interviews. The subjects of the study were selected from strategic units within the municipality which were identified to be the key stakeholders in gender mainstreaming in terms of the institutional arrangements. The results illustrate that despite a commitment to gender mainstreaming in the OR Tambo District Municipality, the institution still faces many challenges in its implementation. These challenges are linked to the absence of an institutional gender mainstreaming policy, poor understanding of gender mainstreaming and sectoral institutional arrangements that hinder the process of implementation. The data confirmed that a lack of skilled human resources hinders the implementation of gender mainstreaming.
- Full Text:
- Date Issued: 2018
General features and kinetic analysis of thermoluminescence from annealed natural quartz
- Thomas, Sunil, Chithambo, Makaiko L
- Authors: Thomas, Sunil , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/112885 , vital:33670 , https://doi.org/10.1016/j.jlumin.2018.02.003
- Description: The aim of this study is to explore the thermoluminescence properties of beta irradiated natural quartz annealed at 900 °C, that is, beyond its second phase inversion temperature of 867 °C. The sample was annealed to improve its sensitivity and to deplete any residual charge from electron traps. The glow-curve corresponding to 10 Gy shows three peaks when measured at 1 °C/s; a dominant one at 71 °C, the subject of this report, and two other ones at 125 and 177 °C. The dose response of the main peak was studied in the range 1–300 Gy. The activation energy of the main glow-peak was evaluated as ~1 eV. Kinetic analyses using various methods show that the main glow-peak follows first order kinetics.
- Full Text: false
- Date Issued: 2018
- Authors: Thomas, Sunil , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/112885 , vital:33670 , https://doi.org/10.1016/j.jlumin.2018.02.003
- Description: The aim of this study is to explore the thermoluminescence properties of beta irradiated natural quartz annealed at 900 °C, that is, beyond its second phase inversion temperature of 867 °C. The sample was annealed to improve its sensitivity and to deplete any residual charge from electron traps. The glow-curve corresponding to 10 Gy shows three peaks when measured at 1 °C/s; a dominant one at 71 °C, the subject of this report, and two other ones at 125 and 177 °C. The dose response of the main peak was studied in the range 1–300 Gy. The activation energy of the main glow-peak was evaluated as ~1 eV. Kinetic analyses using various methods show that the main glow-peak follows first order kinetics.
- Full Text: false
- Date Issued: 2018
Generalized linear models, with applications in fisheries research
- Authors: Sidumo, Bonelwa
- Date: 2018
- Subjects: Western mosquitofish , Analysis of variance , Fisheries Catch effort South Africa Sundays River (Eastern Cape) , Linear models (Statistics) , Multilevel models (Statistics) , Experimental design
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61102 , vital:27975
- Description: Gambusia affinis (G. affinis) is an invasive fish species found in the Sundays River Valley of the Eastern Cape, South Africa, The relative abundance and population dynamics of G. affinis were quantified in five interconnected impoundments within the Sundays River Valley, This study utilised a G. affinis data set to demonstrate various, classical ANOVA models. Generalized linear models were used to standardize catch per unit effort (CPUE) estimates and to determine environmental variables which influenced the CPUE, Based on the generalized linear model results dam age, mean temperature, Oreochromis mossambicus abundance and Glossogobius callidus abundance had a significant effect on the G. affinis CPUE. The Albany Angling Association collected data during fishing tag and release events. These data were utilized to demonstrate repeated measures designs. Mixed-effects models provided a powerful and flexible tool for analyzing clustered data such as repeated measures data and nested data, lienee it has become tremendously popular as a framework for the analysis of bio-behavioral experiments. The results show that the mixed-effects methods proposed in this study are more efficient than those based on generalized linear models. These data were better modeled with mixed-effects models due to their flexibility in handling missing data.
- Full Text:
- Date Issued: 2018
- Authors: Sidumo, Bonelwa
- Date: 2018
- Subjects: Western mosquitofish , Analysis of variance , Fisheries Catch effort South Africa Sundays River (Eastern Cape) , Linear models (Statistics) , Multilevel models (Statistics) , Experimental design
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61102 , vital:27975
- Description: Gambusia affinis (G. affinis) is an invasive fish species found in the Sundays River Valley of the Eastern Cape, South Africa, The relative abundance and population dynamics of G. affinis were quantified in five interconnected impoundments within the Sundays River Valley, This study utilised a G. affinis data set to demonstrate various, classical ANOVA models. Generalized linear models were used to standardize catch per unit effort (CPUE) estimates and to determine environmental variables which influenced the CPUE, Based on the generalized linear model results dam age, mean temperature, Oreochromis mossambicus abundance and Glossogobius callidus abundance had a significant effect on the G. affinis CPUE. The Albany Angling Association collected data during fishing tag and release events. These data were utilized to demonstrate repeated measures designs. Mixed-effects models provided a powerful and flexible tool for analyzing clustered data such as repeated measures data and nested data, lienee it has become tremendously popular as a framework for the analysis of bio-behavioral experiments. The results show that the mixed-effects methods proposed in this study are more efficient than those based on generalized linear models. These data were better modeled with mixed-effects models due to their flexibility in handling missing data.
- Full Text:
- Date Issued: 2018
Genetic analysis reveals harvested Lethrinus nebulosus in the Southwest Indian Ocean comprise two cryptic species
- Healey, Amy J E, Gouws, Gavin, Fennessy, Sean T, Kuguru, Baraka, Sauer, Warwick H H, Shaw, Paul W, McKeown, Niall J
- Authors: Healey, Amy J E , Gouws, Gavin , Fennessy, Sean T , Kuguru, Baraka , Sauer, Warwick H H , Shaw, Paul W , McKeown, Niall J
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124538 , vital:35626 , https://doi.10.1093/icesjms/fsx245
- Description: This study initially aimed to investigate the genetic population/stock structuring of Lethrinus nebulosus in the Southwest Indian Ocean (SWIO) to inform management practices in light of emerging evidence of overharvesting of this species throughout its distribution. Adult samples were genotyped for 14 nuclear microsatellites and by sequencing fragments of the mtDNA control region and COI gene. A salient feature of the data was the congruent cyto-nuclear partitioning of samples into two high divergent, reciprocally monophyletic groups. This indicates that despite no a priori evidence, hitherto described L. nebulosus in the SWIO comprises two cryptic species that co-occur among southern samples. This intermingling indicates that, at least in southern samples, both species are being indiscriminately harvested, which may severely compromise sustainability. Limited microsatellite differentiation was detected within both species, though there was some evidence of isolation in the Mauritian population. In contrast, mtDNA revealed a pattern consistent with chaotic genetic patchiness, likely promoted by stochastic recruitment, which may necessitate a spatial bet-hedging approach to management to satisfy fishery management and conservation goals.
- Full Text:
- Date Issued: 2018
- Authors: Healey, Amy J E , Gouws, Gavin , Fennessy, Sean T , Kuguru, Baraka , Sauer, Warwick H H , Shaw, Paul W , McKeown, Niall J
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124538 , vital:35626 , https://doi.10.1093/icesjms/fsx245
- Description: This study initially aimed to investigate the genetic population/stock structuring of Lethrinus nebulosus in the Southwest Indian Ocean (SWIO) to inform management practices in light of emerging evidence of overharvesting of this species throughout its distribution. Adult samples were genotyped for 14 nuclear microsatellites and by sequencing fragments of the mtDNA control region and COI gene. A salient feature of the data was the congruent cyto-nuclear partitioning of samples into two high divergent, reciprocally monophyletic groups. This indicates that despite no a priori evidence, hitherto described L. nebulosus in the SWIO comprises two cryptic species that co-occur among southern samples. This intermingling indicates that, at least in southern samples, both species are being indiscriminately harvested, which may severely compromise sustainability. Limited microsatellite differentiation was detected within both species, though there was some evidence of isolation in the Mauritian population. In contrast, mtDNA revealed a pattern consistent with chaotic genetic patchiness, likely promoted by stochastic recruitment, which may necessitate a spatial bet-hedging approach to management to satisfy fishery management and conservation goals.
- Full Text:
- Date Issued: 2018
Genomic analysis reveals multiple mismatches between biological and management units in yellowfin tuna (Thunnus albacares)
- Mullins, Rachel B, McKeown, Niall J, Sauer, Warwick H H, Shaw, Paul W
- Authors: Mullins, Rachel B , McKeown, Niall J , Sauer, Warwick H H , Shaw, Paul W
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124549 , vital:35627 , https://doi.10.1093/icesjms/fsy102
- Description: The South African (SAF) yellowfin tuna (Thunnus albacares) fishery represents a potential example of misalignment between management units and biological processes. The SAF fishery spans an operational stock with a boundary at 20_E, either side of which fish are considered part of Atlantic or Indian Ocean regional stocks. However, the actual recruitment of fish from Atlantic and Indian Ocean spawning populations into SAF waters is unknown. To address this knowledge gap, genomic analysis (11 101 SNPs) was performed on samples from Atlantic and Indian Ocean spawning sites, including SAF sites spanning the current stock boundary. Outlier loci conferred high discriminatory power to assignment tests and revealed that all SAF fish were assigned to the Indian Ocean population and that no Atlantic Ocean fish appeared in the SAF samples. Additionally, several Indian Ocean migrants were detected at the Atlantic spawning site demonstrating asymmetric dispersal and the occurrence of a mixed-stock fishery in Atlantic waters. This study highlights both the spatial inaccuracy of current stock designations and a misunderstanding of interactions between the underlying biological units, which must be addressed in light of local and global declines of the species. Specifically, the entire SAF fishery must be managed as part of the Indian Ocean stock.
- Full Text:
- Date Issued: 2018
- Authors: Mullins, Rachel B , McKeown, Niall J , Sauer, Warwick H H , Shaw, Paul W
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124549 , vital:35627 , https://doi.10.1093/icesjms/fsy102
- Description: The South African (SAF) yellowfin tuna (Thunnus albacares) fishery represents a potential example of misalignment between management units and biological processes. The SAF fishery spans an operational stock with a boundary at 20_E, either side of which fish are considered part of Atlantic or Indian Ocean regional stocks. However, the actual recruitment of fish from Atlantic and Indian Ocean spawning populations into SAF waters is unknown. To address this knowledge gap, genomic analysis (11 101 SNPs) was performed on samples from Atlantic and Indian Ocean spawning sites, including SAF sites spanning the current stock boundary. Outlier loci conferred high discriminatory power to assignment tests and revealed that all SAF fish were assigned to the Indian Ocean population and that no Atlantic Ocean fish appeared in the SAF samples. Additionally, several Indian Ocean migrants were detected at the Atlantic spawning site demonstrating asymmetric dispersal and the occurrence of a mixed-stock fishery in Atlantic waters. This study highlights both the spatial inaccuracy of current stock designations and a misunderstanding of interactions between the underlying biological units, which must be addressed in light of local and global declines of the species. Specifically, the entire SAF fishery must be managed as part of the Indian Ocean stock.
- Full Text:
- Date Issued: 2018
Geometry of deformed special relativity
- Authors: Sixaba, Vuyile
- Date: 2018
- Subjects: Special relativity (Physics) , Quantum gravity , Quantum theory , Geometry , Heisenberg uncertainty principle
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/59478 , vital:27615
- Description: We undertake a study of the classical regime in which Planck's constant and Newton's gravitational constant are negligible, but not their ratio, the Planck mass, in hopes that this could possibly lead to testable quantum gravity (QG) effects in a classical regime. In this quest for QG phenomenology we consider modifications of the standard dispersion relation of a free particle known as deformed special relativity (DSR). We try to geometrize DSR to find the geometric origin of the spacetime and momentum space. In particular, we adopt the framework of Hamilton geometry which is set up on phase space, as the cotangent bundle of configuration space in order to derive a purely phase space formulation of DSR. This is necessary when one wants to understand potential links of DSR with modifications of quantum mechanics such as Generalised Uncertainty Principles. It is subsequently observed that space-time and momentum space emerge naturally as curved and intertwined spaces. In conclusion we mention examples and applications of this framework as well as potential future developments.
- Full Text:
- Date Issued: 2018
- Authors: Sixaba, Vuyile
- Date: 2018
- Subjects: Special relativity (Physics) , Quantum gravity , Quantum theory , Geometry , Heisenberg uncertainty principle
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/59478 , vital:27615
- Description: We undertake a study of the classical regime in which Planck's constant and Newton's gravitational constant are negligible, but not their ratio, the Planck mass, in hopes that this could possibly lead to testable quantum gravity (QG) effects in a classical regime. In this quest for QG phenomenology we consider modifications of the standard dispersion relation of a free particle known as deformed special relativity (DSR). We try to geometrize DSR to find the geometric origin of the spacetime and momentum space. In particular, we adopt the framework of Hamilton geometry which is set up on phase space, as the cotangent bundle of configuration space in order to derive a purely phase space formulation of DSR. This is necessary when one wants to understand potential links of DSR with modifications of quantum mechanics such as Generalised Uncertainty Principles. It is subsequently observed that space-time and momentum space emerge naturally as curved and intertwined spaces. In conclusion we mention examples and applications of this framework as well as potential future developments.
- Full Text:
- Date Issued: 2018
Global trends of local ecological knowledge and future implications
- Aswani, Shankar, Lemahieu, Anne, Sauer, Warwick H H
- Authors: Aswani, Shankar , Lemahieu, Anne , Sauer, Warwick H H
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70504 , vital:29668 , https://doi.org/10.1371/journal.pone.0195440
- Description: Local and indigenous knowledge is being transformed globally, particularly being eroded when pertaining to ecology. In many parts of the world, rural and indigenous communities are facing tremendous cultural, economic and environmental changes, which contribute to weaken their local knowledge base. In the face of profound and ongoing environmental changes, both cultural and biological diversity are likely to be severely impacted as well as local resilience capacities from this loss. In this global literature review, we analyse the drivers of various types of local and indigenous ecological knowledge transformation and assess the directionality of the reported change. Results of this analysis show a global impoverishment of local and indigenous knowledge with 77% of papers reporting the loss of knowledge driven by globalization, modernization, and market integration. The recording of this loss, however, is not symmetrical, with losses being recorded more strongly in medicinal and ethnobotanical knowledge. Persistence of knowledge (15% of the studies) occurred in studies where traditional practices were being maintained consiously and where hybrid knowledge was being produced as a resut of certain types of incentives created by economic development. This review provides some insights into local and indigenous ecological knowledge change, its causes and implications, and recommends venues for the development of replicable and comparative research. The larger implication of these results is that because of the interconnection between cultural and biological diversity, the loss of local and indigenous knowledge is likely to critically threaten effective conservation of biodiversity, particularly in community-based conservation local efforts.
- Full Text:
- Date Issued: 2018
- Authors: Aswani, Shankar , Lemahieu, Anne , Sauer, Warwick H H
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70504 , vital:29668 , https://doi.org/10.1371/journal.pone.0195440
- Description: Local and indigenous knowledge is being transformed globally, particularly being eroded when pertaining to ecology. In many parts of the world, rural and indigenous communities are facing tremendous cultural, economic and environmental changes, which contribute to weaken their local knowledge base. In the face of profound and ongoing environmental changes, both cultural and biological diversity are likely to be severely impacted as well as local resilience capacities from this loss. In this global literature review, we analyse the drivers of various types of local and indigenous ecological knowledge transformation and assess the directionality of the reported change. Results of this analysis show a global impoverishment of local and indigenous knowledge with 77% of papers reporting the loss of knowledge driven by globalization, modernization, and market integration. The recording of this loss, however, is not symmetrical, with losses being recorded more strongly in medicinal and ethnobotanical knowledge. Persistence of knowledge (15% of the studies) occurred in studies where traditional practices were being maintained consiously and where hybrid knowledge was being produced as a resut of certain types of incentives created by economic development. This review provides some insights into local and indigenous ecological knowledge change, its causes and implications, and recommends venues for the development of replicable and comparative research. The larger implication of these results is that because of the interconnection between cultural and biological diversity, the loss of local and indigenous knowledge is likely to critically threaten effective conservation of biodiversity, particularly in community-based conservation local efforts.
- Full Text:
- Date Issued: 2018
Glycosylated zinc phthalocyanine-gold nanoparticle conjugates for photodynamic therapy
- Dube, Edith, Oluwole, David O, Nwaji, Njemuwa, Nyokong, Tebello
- Authors: Dube, Edith , Oluwole, David O , Nwaji, Njemuwa , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234524 , vital:50205 , xlink:href="https://doi.org/10.1016/j.saa.2018.05.081"
- Description: In this work, we report on the synthesis of tris-[(2,2,7,7-tetramethyltetrahydro-3aH-bis([1,3]dioxolo)[4,5-b:4′,5′-d]pyran-5-yl)methoxy)-2-(4-benzo[d]thiazol-2-ylphenoxyphthalocyaninato] zinc(II) (complex 3) and its linkage to gold nanoparticles (AuNPs) of different shapes through S-Au/N-Au self-assembly. The conjugates of complex 3 (with both gold nanorods (AuNR) and nanospheres (AuNS)), displayed decreased fluorescence quantum yield with corresponding improved triplet and singlet quantum yields compared to complex 3 alone, however 3-AuNR showed improved properties than 3-AuNS. Complex 3 showed relatively low in vitro dark cytotoxicity against the epithelial breast cancer cells with cell survival ≥ 85% at concentration ≤ 160 μg/mL but afforded reduced photodynamic therapy activity which may be due to aggregation. 3-AuNR afforded superior PDT activity with more than 50% viable cells at concentration ≥ 40 μg/mL in comparison to 3-AuNS with more than 50% viable cells at concentration ≥ 80 μg/mL. The superior activity of 3-AuNR is attributed to the photothermal therapy effect since nanorods absorb more light at 680 nm than nanospheres.
- Full Text:
- Date Issued: 2018
- Authors: Dube, Edith , Oluwole, David O , Nwaji, Njemuwa , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234524 , vital:50205 , xlink:href="https://doi.org/10.1016/j.saa.2018.05.081"
- Description: In this work, we report on the synthesis of tris-[(2,2,7,7-tetramethyltetrahydro-3aH-bis([1,3]dioxolo)[4,5-b:4′,5′-d]pyran-5-yl)methoxy)-2-(4-benzo[d]thiazol-2-ylphenoxyphthalocyaninato] zinc(II) (complex 3) and its linkage to gold nanoparticles (AuNPs) of different shapes through S-Au/N-Au self-assembly. The conjugates of complex 3 (with both gold nanorods (AuNR) and nanospheres (AuNS)), displayed decreased fluorescence quantum yield with corresponding improved triplet and singlet quantum yields compared to complex 3 alone, however 3-AuNR showed improved properties than 3-AuNS. Complex 3 showed relatively low in vitro dark cytotoxicity against the epithelial breast cancer cells with cell survival ≥ 85% at concentration ≤ 160 μg/mL but afforded reduced photodynamic therapy activity which may be due to aggregation. 3-AuNR afforded superior PDT activity with more than 50% viable cells at concentration ≥ 40 μg/mL in comparison to 3-AuNS with more than 50% viable cells at concentration ≥ 80 μg/mL. The superior activity of 3-AuNR is attributed to the photothermal therapy effect since nanorods absorb more light at 680 nm than nanospheres.
- Full Text:
- Date Issued: 2018
Going to university: the Influence of higher education on the lives of young South Africans
- Case, Jennifer M, Marshall, Delia, McKenna, Sioux, Mogashana, Disaapele
- Authors: Case, Jennifer M , Marshall, Delia , McKenna, Sioux , Mogashana, Disaapele
- Date: 2018
- Subjects: Education, Higher -- Aims and objectives -- South Africa Education, Higher -- South Africa College students -- South Africa Education, Higher -- South Africa -- Social aspects Education, Higher -- South Africa -- Economic aspects
- Language: English
- Type: e-book , text
- Identifier: http://hdl.handle.net/10962/61134 , vital:27981 , https://books.google.co.za/books?id=T-RMDwAAQBAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false
- Full Text: false
- Date Issued: 2018
- Authors: Case, Jennifer M , Marshall, Delia , McKenna, Sioux , Mogashana, Disaapele
- Date: 2018
- Subjects: Education, Higher -- Aims and objectives -- South Africa Education, Higher -- South Africa College students -- South Africa Education, Higher -- South Africa -- Social aspects Education, Higher -- South Africa -- Economic aspects
- Language: English
- Type: e-book , text
- Identifier: http://hdl.handle.net/10962/61134 , vital:27981 , https://books.google.co.za/books?id=T-RMDwAAQBAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false
- Full Text: false
- Date Issued: 2018
Graphene quantum dots and their metallophthalocyanines nanoconjugates as novel photoluminescent nanosensors
- Authors: Achadu, Ojodomo John
- Date: 2018
- Subjects: Quantum dots , Graphene , Phthalocyanines , Nanoconjugates , Novel photoluminescent nanosensors , Metallophthalocyanines
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/60719 , vital:27821
- Description: The fabrication and application of graphene quantum dots (GQDs)-based photoluminescent probes for the detection of analytes is presented. GQDs were functionalized with complexes such as metallophthalocyanines (MPcs), metal nanoparticles (Au@Ag NPs), 2,2,6,6-tetramethyl(piperidin-1-yl)oxyl (TEMPO), maleimide and thymine for the sensing of target analytes such as ascorbic acid (AA), biothiols (cysteine, homocysteine and glutathione) and mercury ion (Hg²+). The design strategy and approach was based on the quenching of the fluorescence of the GQDs upon functionalization with the above-mentioned complexes, which could be restored in the presence of the target analytes (due to their specific interaction affinity with the complexes). For the detection of AA, GQDs were covalently and/or non-covalently conjugated to TEMPO-bearing complexes to form GQDs-4A-TEMPO and GQDs-TEMPO-MPc systems with nanomolar limits of detection. For the detection of biothiols, Au@Ag NPs and maleimide-bearing complexes (MPc), which have specific affinity to interact with biothiols, were deployed. Hg²+ detection involved the use of GQDs and/or MPcs with thiol and thymine groups, respectively. In addition, a smart sensing platform was designed for the dual detection of biothiols and Hg²+ using supramolecular hybrid of polyethyleneimine functionalized-GQDs and MPc-Au@Ag conjugate. The probe could detect, in a sequential manner, Hg²+ and biothiols with high sensitivity. Results obtained from the LODs of the probes showed that GQDs sensing performances could be enhanced in the presence of MPcs. The probes designed in this work were successfully deployed in the assays of the target analytes in real samples and the recoveries obtained confirmed the analytical applicability of the probes.
- Full Text:
- Date Issued: 2018
- Authors: Achadu, Ojodomo John
- Date: 2018
- Subjects: Quantum dots , Graphene , Phthalocyanines , Nanoconjugates , Novel photoluminescent nanosensors , Metallophthalocyanines
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/60719 , vital:27821
- Description: The fabrication and application of graphene quantum dots (GQDs)-based photoluminescent probes for the detection of analytes is presented. GQDs were functionalized with complexes such as metallophthalocyanines (MPcs), metal nanoparticles (Au@Ag NPs), 2,2,6,6-tetramethyl(piperidin-1-yl)oxyl (TEMPO), maleimide and thymine for the sensing of target analytes such as ascorbic acid (AA), biothiols (cysteine, homocysteine and glutathione) and mercury ion (Hg²+). The design strategy and approach was based on the quenching of the fluorescence of the GQDs upon functionalization with the above-mentioned complexes, which could be restored in the presence of the target analytes (due to their specific interaction affinity with the complexes). For the detection of AA, GQDs were covalently and/or non-covalently conjugated to TEMPO-bearing complexes to form GQDs-4A-TEMPO and GQDs-TEMPO-MPc systems with nanomolar limits of detection. For the detection of biothiols, Au@Ag NPs and maleimide-bearing complexes (MPc), which have specific affinity to interact with biothiols, were deployed. Hg²+ detection involved the use of GQDs and/or MPcs with thiol and thymine groups, respectively. In addition, a smart sensing platform was designed for the dual detection of biothiols and Hg²+ using supramolecular hybrid of polyethyleneimine functionalized-GQDs and MPc-Au@Ag conjugate. The probe could detect, in a sequential manner, Hg²+ and biothiols with high sensitivity. Results obtained from the LODs of the probes showed that GQDs sensing performances could be enhanced in the presence of MPcs. The probes designed in this work were successfully deployed in the assays of the target analytes in real samples and the recoveries obtained confirmed the analytical applicability of the probes.
- Full Text:
- Date Issued: 2018
Graphite: origin, deposits and economics : an exploration study of the Orom Graphite project
- Van den Berg, Jacobus Petrus
- Authors: Van den Berg, Jacobus Petrus
- Date: 2018
- Subjects: Graphite , Ore deposits , Geophysics , Graphite mines and mining Economic aspects Africa, East , Trenches , Project management
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63786 , vital:28489
- Description: Developing exploration projects successfully requires that the Reasonable Prospects for Eventual Economic Extraction (RPEEE) be confirmed and based on the global market perception and trend. The exploration methods applied in the attempt to establish this RPEEE must be based on a key management framework that assures the results, and eventually the conclusion, are obtained with best practical and technical approaches whilst managing the risks and capitalizing on each result. The Orom Graphite project is located within the East African Orogenic belt, a suture zone between the Congo craton and the SLAMIN shield, formed during the formation of Gondwana during the late Proterozoic to early-Phanerozoic era. The closing of the Mozambique ocean, and the eventual collision between the craton and shield, occurred along the paleo-earths equator and migrated towards lower latitudes. This, along with the period’s biodiversity boom, provided the perfect deposition environment for carbonaceous sediments which were later metamorphosed to amphibolite and granulites grade metamorphism, resulting in the carbonization and the eventual graphitization of these carbonaceous sediments. The project is located within a poorly developed part of Uganda with the closest port situated some 1 500 km to the east in Kenya. The poorly developed infrastructure along with probable high logistical cost assigns a low competitivity index if compared to the economic costs of peer projects. However, the potential resources of the Orom Graphite project suggest that the Life of Mine (LOM) can rival the largest resource currently reported within the market. The current market conditions suggest that a possible oversupply of graphite concentrate will dominate the market within the next 4 to 10 years. This suggests that new graphite projects such as the Orom Graphite project are likely to develop into the production phase once the global supply and demand stabilize. This requires the Orom Graphite project to develop from its current scoping study level to a project development study level associated with a definitive feasibility study. To date, the project developed through mapping, reconnaissance drilling, geophysical survey and trenching programs increasing the Net Present Value (NPV) considerably based upon a Cost-Based Valuation approach using Prospectivity Enhancement Multiplier (PEM). The metallurgical studies could however not produce a graphite concentrate product within industrial grade standards. The risk associated with developing the project further into the Mineral Resource Estimation (MRE) phase was quantified and risk was evaluated by implementing a point decision tree and calculating the Expected Monetary Value (EMV). Due to the unfavourable metallurgical results obtained to date, the risk associated with undertaking an additional metallurgical test is considerable with a slight chance of producing a negative project value estimated at 65%. JP van den Berg Rhodes University Overall, the Orom Graphite project contains favourable geological formations with a potential large resource. Market trends indicate that a considerable resource is currently being developed and can supply the global market for the next 4 to 10 years. The project’s location within a landlocked country decreases its economic competitiveness with peer project and the unfavourable, but not conclusive, metallurgical results obtained during the scoping phase do not instil confidence that the project will develop into a productive mine soon. Managing the project development with future graphite demand in mind is the key to determining whether the project still has future value.
- Full Text:
- Date Issued: 2018
- Authors: Van den Berg, Jacobus Petrus
- Date: 2018
- Subjects: Graphite , Ore deposits , Geophysics , Graphite mines and mining Economic aspects Africa, East , Trenches , Project management
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63786 , vital:28489
- Description: Developing exploration projects successfully requires that the Reasonable Prospects for Eventual Economic Extraction (RPEEE) be confirmed and based on the global market perception and trend. The exploration methods applied in the attempt to establish this RPEEE must be based on a key management framework that assures the results, and eventually the conclusion, are obtained with best practical and technical approaches whilst managing the risks and capitalizing on each result. The Orom Graphite project is located within the East African Orogenic belt, a suture zone between the Congo craton and the SLAMIN shield, formed during the formation of Gondwana during the late Proterozoic to early-Phanerozoic era. The closing of the Mozambique ocean, and the eventual collision between the craton and shield, occurred along the paleo-earths equator and migrated towards lower latitudes. This, along with the period’s biodiversity boom, provided the perfect deposition environment for carbonaceous sediments which were later metamorphosed to amphibolite and granulites grade metamorphism, resulting in the carbonization and the eventual graphitization of these carbonaceous sediments. The project is located within a poorly developed part of Uganda with the closest port situated some 1 500 km to the east in Kenya. The poorly developed infrastructure along with probable high logistical cost assigns a low competitivity index if compared to the economic costs of peer projects. However, the potential resources of the Orom Graphite project suggest that the Life of Mine (LOM) can rival the largest resource currently reported within the market. The current market conditions suggest that a possible oversupply of graphite concentrate will dominate the market within the next 4 to 10 years. This suggests that new graphite projects such as the Orom Graphite project are likely to develop into the production phase once the global supply and demand stabilize. This requires the Orom Graphite project to develop from its current scoping study level to a project development study level associated with a definitive feasibility study. To date, the project developed through mapping, reconnaissance drilling, geophysical survey and trenching programs increasing the Net Present Value (NPV) considerably based upon a Cost-Based Valuation approach using Prospectivity Enhancement Multiplier (PEM). The metallurgical studies could however not produce a graphite concentrate product within industrial grade standards. The risk associated with developing the project further into the Mineral Resource Estimation (MRE) phase was quantified and risk was evaluated by implementing a point decision tree and calculating the Expected Monetary Value (EMV). Due to the unfavourable metallurgical results obtained to date, the risk associated with undertaking an additional metallurgical test is considerable with a slight chance of producing a negative project value estimated at 65%. JP van den Berg Rhodes University Overall, the Orom Graphite project contains favourable geological formations with a potential large resource. Market trends indicate that a considerable resource is currently being developed and can supply the global market for the next 4 to 10 years. The project’s location within a landlocked country decreases its economic competitiveness with peer project and the unfavourable, but not conclusive, metallurgical results obtained during the scoping phase do not instil confidence that the project will develop into a productive mine soon. Managing the project development with future graphite demand in mind is the key to determining whether the project still has future value.
- Full Text:
- Date Issued: 2018
Grapple cable yarding: a productivity model for fast-growing tree plantations in Sarawak, Malaysia
- Authors: Engelbrecht, Riaan
- Date: 2018
- Subjects: Tree farms -- Malaysia -- Sarawak , Forests and forestry -- Malaysia -- Sarawak Forest productivity -- Malaysia -- Sarawak
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/22049 , vital:29816
- Description: Today, the two most important tasks faced by harvesting foresters and contractors are selecting the equipment and systems best suited to the site, and then to use this equipment in the best way possible (MacDonald, 1999). Experts estimate that the importance of tree plantations will continue to grow and that by 2050 75 per cent of the global fibre supply will be sourced from dedicated plantations (Ragauskas et al., 2006). To meet this growing demand plantations will most likely expand to steep slopes due to the priority given to agricultural and urban development, on flat land. New technological advancements in both cable yarding and ground-based harvesting systems has to a certain extent provided forest engineers with more options to choose from. Whether considering these options individually or in combination, they will have to make good choices in order to realise the full potential of forest plantations. One of the most promising techniques consist of an excavator-based unguyed yarder equipped with a new radio-controlled grapple carriage, fed by another excavator stationed on the cut-over. This system is very productive, avoids in-stand traffic and removes operators from positions of high risk. This long-term study was conducted on 12 different teams equipped with the new technology, operating in the fast-growing Acacia mangium plantations of Sarawak, Malaysia. Data were collected continuously for almost 8 months and represented 555 shifts, or over 55,000 yarding cycles - each recorded individually. This large data pool allowed for the development of robust models for system production, utilization and availability estimated respectively at: 63 m3 per productive machine hour (excluding all delays), 63 per cent and 93 per cent. The study also determined the effects of yarder type and team competence on productivity and utilization. Regression analysis of experimental data yielded a strong productivity forecast model that was highly significant, which accounted for 50 per cent of the total variability in the dataset and was validated with a non-significant error estimated at less than 1 per cent. The models reported in this study are especially robust, because they were obtained from a long-term study that covered multiple teams and accumulated an exceptionally large number of observations. While gained specifically on one yarder make (Alpine Yarder) and a specific plantation type (Acacia mangium), the information in this study can be extended to other similar machines and plantations, because the sheer volume of data allows cautious generalization. The teachings of kaizen, which suggest small-step work improvements, was adopted in order to propose the process of possible improvements, by combining elements of other harvesting systems as shown in Figure 1 below (Vorn Industries, 2017). Forestry is essentially a problem of transportation (Schenck, 1911) and the efficiency of such a transportation system will ultimately be determined by technology developments which drive system productivity (Ger & Klvac, 2014). Therefore, when we talk about systems for the future we should view them not as predictions or as prescriptions but as options that may be selected or rejected (Wood, 1979).
- Full Text:
- Date Issued: 2018
- Authors: Engelbrecht, Riaan
- Date: 2018
- Subjects: Tree farms -- Malaysia -- Sarawak , Forests and forestry -- Malaysia -- Sarawak Forest productivity -- Malaysia -- Sarawak
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/22049 , vital:29816
- Description: Today, the two most important tasks faced by harvesting foresters and contractors are selecting the equipment and systems best suited to the site, and then to use this equipment in the best way possible (MacDonald, 1999). Experts estimate that the importance of tree plantations will continue to grow and that by 2050 75 per cent of the global fibre supply will be sourced from dedicated plantations (Ragauskas et al., 2006). To meet this growing demand plantations will most likely expand to steep slopes due to the priority given to agricultural and urban development, on flat land. New technological advancements in both cable yarding and ground-based harvesting systems has to a certain extent provided forest engineers with more options to choose from. Whether considering these options individually or in combination, they will have to make good choices in order to realise the full potential of forest plantations. One of the most promising techniques consist of an excavator-based unguyed yarder equipped with a new radio-controlled grapple carriage, fed by another excavator stationed on the cut-over. This system is very productive, avoids in-stand traffic and removes operators from positions of high risk. This long-term study was conducted on 12 different teams equipped with the new technology, operating in the fast-growing Acacia mangium plantations of Sarawak, Malaysia. Data were collected continuously for almost 8 months and represented 555 shifts, or over 55,000 yarding cycles - each recorded individually. This large data pool allowed for the development of robust models for system production, utilization and availability estimated respectively at: 63 m3 per productive machine hour (excluding all delays), 63 per cent and 93 per cent. The study also determined the effects of yarder type and team competence on productivity and utilization. Regression analysis of experimental data yielded a strong productivity forecast model that was highly significant, which accounted for 50 per cent of the total variability in the dataset and was validated with a non-significant error estimated at less than 1 per cent. The models reported in this study are especially robust, because they were obtained from a long-term study that covered multiple teams and accumulated an exceptionally large number of observations. While gained specifically on one yarder make (Alpine Yarder) and a specific plantation type (Acacia mangium), the information in this study can be extended to other similar machines and plantations, because the sheer volume of data allows cautious generalization. The teachings of kaizen, which suggest small-step work improvements, was adopted in order to propose the process of possible improvements, by combining elements of other harvesting systems as shown in Figure 1 below (Vorn Industries, 2017). Forestry is essentially a problem of transportation (Schenck, 1911) and the efficiency of such a transportation system will ultimately be determined by technology developments which drive system productivity (Ger & Klvac, 2014). Therefore, when we talk about systems for the future we should view them not as predictions or as prescriptions but as options that may be selected or rejected (Wood, 1979).
- Full Text:
- Date Issued: 2018
Guest inclusion behaviour of zirconium(IV)- based polycarboxylate complexes: a study of metal-organic frameworks
- Hulushe, Siyabonga Theophillus
- Authors: Hulushe, Siyabonga Theophillus
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63710 , vital:28474
- Description: Expected release date-April 2019
- Full Text:
- Date Issued: 2018
- Authors: Hulushe, Siyabonga Theophillus
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63710 , vital:28474
- Description: Expected release date-April 2019
- Full Text:
- Date Issued: 2018
Guidelines for and evaluation of the design of technology-supported lessons to teach basic programming principles to deaf and hard of hearing learners: a case study of a school for the deaf
- Authors: Wassermann, Ulza
- Date: 2018
- Subjects: Deaf -- Education , Hearing impaired children -- Education Computers and people with disabilities Communication devices for people with disabilities Information technology -- Education
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/36347 , vital:33925
- Description: Deaf and Hard of Hearing (DHH) learners are part of a diverse population with unique learning challenges, strengths and needs. Learning material should be developed specifically for them to provide for their needs and capitalise on their strengths. These materials should include visual material and strategies as well as sign language. Furthermore, DHH learners have the same capacity for learning as hearing learners. However, in South Africa, DHH learners do not have adequate access to training in computer-related subjects, and therefore no material exists that has been developed specifically for DHH learners who want to learn a programming language. This research provides guidelines on the way technology-supported lessons can be designed to teach basic programming principles using the programming language Scratch, to DHH learners. Provision was made for the South African context where limited technology is available at most schools for DHH learners, but where most educators have access to Microsoft Office applications – specifically MS PowerPoint. Two goals were pursued. The primary goal of this research project was to determine the user experience (UX) of the participants (both learners and educators) during and after using and attending the technology-supported lessons. This was achieved through a case study. Four UX evaluation elements were evaluated in this project. They were: usability, accessibility, emotional user reaction, and hedonic aspects. Questionnaires, semi-structured interviews as well as participant-observation were used to determine the UX of participants. The UX evaluation provided sufficient evidence to claim that UX of participants was satisfactory, and therefore the guidelines that were developed to create technology-supported lessons to teach basic programming principles to DHH learners were appropriate. The secondary goal was to develop guidelines for the design of technology-supported lessons to teach programming to DHH learners, and to apply these guidelines to develop a high-fidelity, fully functional prototype – a set of technology-supported lessons. This was achieved through a prototype construction research strategy. The lessons consisted of two vocabulary lessons and one programming lesson. The words that were taught in the vocabulary lesson were either terms appearing in the interface of Scratch, or words needed in the explanation of programming principles and Scratch context. The programming lesson (a PowerPoint slide show) was a guide for the educator to present the content in a logical way, and not to leave out important information. It used multimedia techniques (colour, pictures, animation) to explain programming concepts, and to display the tasks to be completed to the learners, so that they could remember the sequence of the steps. Practical strategies have been included in the guidelines to address the learning challenges DHH experience in the following areas: Comprehension skills, application of knowledge and knowledge organisation, relational and individual-item orientations, metacognition, memory, distractibility. The guidelines referred to techniques and principles that can be followed to design the interface and navigation tools of a technology-supported lesson; enhance communication with DHH learners, and provide support for them to work independently; specify the educator’s role and attitude when facilitating or presenting programming lessons and to structure a programming lesson.
- Full Text:
- Date Issued: 2018
- Authors: Wassermann, Ulza
- Date: 2018
- Subjects: Deaf -- Education , Hearing impaired children -- Education Computers and people with disabilities Communication devices for people with disabilities Information technology -- Education
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/36347 , vital:33925
- Description: Deaf and Hard of Hearing (DHH) learners are part of a diverse population with unique learning challenges, strengths and needs. Learning material should be developed specifically for them to provide for their needs and capitalise on their strengths. These materials should include visual material and strategies as well as sign language. Furthermore, DHH learners have the same capacity for learning as hearing learners. However, in South Africa, DHH learners do not have adequate access to training in computer-related subjects, and therefore no material exists that has been developed specifically for DHH learners who want to learn a programming language. This research provides guidelines on the way technology-supported lessons can be designed to teach basic programming principles using the programming language Scratch, to DHH learners. Provision was made for the South African context where limited technology is available at most schools for DHH learners, but where most educators have access to Microsoft Office applications – specifically MS PowerPoint. Two goals were pursued. The primary goal of this research project was to determine the user experience (UX) of the participants (both learners and educators) during and after using and attending the technology-supported lessons. This was achieved through a case study. Four UX evaluation elements were evaluated in this project. They were: usability, accessibility, emotional user reaction, and hedonic aspects. Questionnaires, semi-structured interviews as well as participant-observation were used to determine the UX of participants. The UX evaluation provided sufficient evidence to claim that UX of participants was satisfactory, and therefore the guidelines that were developed to create technology-supported lessons to teach basic programming principles to DHH learners were appropriate. The secondary goal was to develop guidelines for the design of technology-supported lessons to teach programming to DHH learners, and to apply these guidelines to develop a high-fidelity, fully functional prototype – a set of technology-supported lessons. This was achieved through a prototype construction research strategy. The lessons consisted of two vocabulary lessons and one programming lesson. The words that were taught in the vocabulary lesson were either terms appearing in the interface of Scratch, or words needed in the explanation of programming principles and Scratch context. The programming lesson (a PowerPoint slide show) was a guide for the educator to present the content in a logical way, and not to leave out important information. It used multimedia techniques (colour, pictures, animation) to explain programming concepts, and to display the tasks to be completed to the learners, so that they could remember the sequence of the steps. Practical strategies have been included in the guidelines to address the learning challenges DHH experience in the following areas: Comprehension skills, application of knowledge and knowledge organisation, relational and individual-item orientations, metacognition, memory, distractibility. The guidelines referred to techniques and principles that can be followed to design the interface and navigation tools of a technology-supported lesson; enhance communication with DHH learners, and provide support for them to work independently; specify the educator’s role and attitude when facilitating or presenting programming lessons and to structure a programming lesson.
- Full Text:
- Date Issued: 2018
Guidelines for the protection of stored sensitive information assets within small, medium and micro enterprises
- Authors: Scharnick, Nicholas
- Date: 2018
- Subjects: Computer security , Information technology -- Security measures Data protection Business -- Data processing -- Security measures Small business -- Data processing -- Security measures -- South Africa
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/34799 , vital:33452
- Description: Technology has become important in the business environment as it ensures that a business is competitive and it also drives the business processes. However, in the era of mobile devices, easy access to the internet and a wide variety of other communication mechanisms; the security of the business from a technological perspective is constantly under threat. Thus, the problem that this research aims to address is that there is currently a lack of understanding by SMMEs in protecting their stored sensitive information assets. This study intends to assist small businesses, such as those within the Small Medium and Micro Enterprises (SMME) on how to protect and secure information while it is in storage. SMMEs usually do not have available resources to fully address information security related concerns that could pose a threat to the well being and success of the business. In order to address the problem identified, and assist SMMEs with better protecting their stored information assets, the outcomes of this research is to develop guidelines to assist SMMEs in protecting stored sensitive information assets. Through the use of a qualitative content analysis, a literature review, a number of information security standards, best practices, and frameworks, including the ISO27000 series of standards, COBIT, ITIL, and various NIST publications were analysed to determine how these security approaches address security concerns that arise when considering the storage of sensitive information. Following the literature analysis, a survey was developed and distributed to a wide variety of SMMEs in order to determine what their information security requirements might be, as well as how they address information security. The results obtained from this, coupled with the literature analysis, served as input for the development of a number of guidelines that can assist SMMEs in protecting stored sensitive information assets.
- Full Text:
- Date Issued: 2018
- Authors: Scharnick, Nicholas
- Date: 2018
- Subjects: Computer security , Information technology -- Security measures Data protection Business -- Data processing -- Security measures Small business -- Data processing -- Security measures -- South Africa
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/34799 , vital:33452
- Description: Technology has become important in the business environment as it ensures that a business is competitive and it also drives the business processes. However, in the era of mobile devices, easy access to the internet and a wide variety of other communication mechanisms; the security of the business from a technological perspective is constantly under threat. Thus, the problem that this research aims to address is that there is currently a lack of understanding by SMMEs in protecting their stored sensitive information assets. This study intends to assist small businesses, such as those within the Small Medium and Micro Enterprises (SMME) on how to protect and secure information while it is in storage. SMMEs usually do not have available resources to fully address information security related concerns that could pose a threat to the well being and success of the business. In order to address the problem identified, and assist SMMEs with better protecting their stored information assets, the outcomes of this research is to develop guidelines to assist SMMEs in protecting stored sensitive information assets. Through the use of a qualitative content analysis, a literature review, a number of information security standards, best practices, and frameworks, including the ISO27000 series of standards, COBIT, ITIL, and various NIST publications were analysed to determine how these security approaches address security concerns that arise when considering the storage of sensitive information. Following the literature analysis, a survey was developed and distributed to a wide variety of SMMEs in order to determine what their information security requirements might be, as well as how they address information security. The results obtained from this, coupled with the literature analysis, served as input for the development of a number of guidelines that can assist SMMEs in protecting stored sensitive information assets.
- Full Text:
- Date Issued: 2018
Gully erosion as a mechanism for wetland formation: an examination of two contrasting landscapes
- Pulley, Simon, Ellery, William F N, Lagesse, Juliette V, Schlegel, P Philippa, McNamara, Shaun J
- Authors: Pulley, Simon , Ellery, William F N , Lagesse, Juliette V , Schlegel, P Philippa , McNamara, Shaun J
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144410 , vital:38343 , DOI: 10.1002/ldr.2972
- Description: Wetlands occupy broad, gently sloping valleys characterised by net deposition. Consequently, gully incision is viewed as an agent of wetland destruction. However, little attention has been given to the role of gullies in natural wetland formation. This paper determines if gully cutting and filling cycles have led to wetland formation in both an extant eroding wetland and a semi‐arid environment that once supported wetlands. At both sites, the valley fill was investigated to identify infilled gullies, and a 14C date was obtained from the gully fill.
- Full Text:
- Date Issued: 2018
- Authors: Pulley, Simon , Ellery, William F N , Lagesse, Juliette V , Schlegel, P Philippa , McNamara, Shaun J
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144410 , vital:38343 , DOI: 10.1002/ldr.2972
- Description: Wetlands occupy broad, gently sloping valleys characterised by net deposition. Consequently, gully incision is viewed as an agent of wetland destruction. However, little attention has been given to the role of gullies in natural wetland formation. This paper determines if gully cutting and filling cycles have led to wetland formation in both an extant eroding wetland and a semi‐arid environment that once supported wetlands. At both sites, the valley fill was investigated to identify infilled gullies, and a 14C date was obtained from the gully fill.
- Full Text:
- Date Issued: 2018
Habitat use of important juvenile fish species in temperate Earnestine nursery areas with notes on feeding ecology and historical shifts to assist with conservation planning, South Africa
- Authors: Nel, Larize
- Date: 2018
- Subjects: Mariculture -- South Africa , Fishes -- Ecology -- South Africa Fishes -- Food -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/32904 , vital:32396
- Description: Estuaries are among the most productive ecosystems worldwide as they provide important refuge and feeding areas for the juveniles of many marine species, many of which have recreational importance. The use of these nursery areas by juvenile fishes in South Africa are in need of further investigation and many critical areas such as shallow water creeks and vegetated habitats remain understudied. By using mixed-methods, estuarine fish assemblages were assessed in five permanently open estuaries in the Eastern Cape Province of South Africa. A total of 81 428 comprising 24 families and 40 species of fishes were sampled by means of a 50 m seine net (12 mm mesh) along the length of these systems that comprised of six equidistant sites during the summer recruitment period (October - December) of 2014 and 2015. A higher catch per unit effort (CPUE) was recorded in 2014 (68 875) compared to the following year where a decline of approximately 82% was observed in the catch (12 553) for all estuaries except the Kromme Estuary. Catches were mainly dominated by the marine estuarine dependent sparid, Rhabdosargus holubi and the solely estuarine clupeid, Gilchristella aestuaria. Species compositions and catch abundance with regards to historical catches showed that the abundance of many marine estuarine dependent juveniles as well as important recreational species have declined within these systems and are mainly attributed to marine overfishing and the exploitation of undersized individuals in estuarine nurseries. Juvenile fishes that occur in these estuaries utilize a range of vegetated habitats ranging from salt marsh creeks, Zostera capensis beds, Spartina maritima and previously unexplored Phragmites australis areas. Sampling was achieved by using passive, double-winged, six-hooped fyke nets, 1 mm mesh size that was secured in placed on the nocturnal flood tide at each inundated vegetated and adjacent unvegetated habitat types. Higher catches were frequently recorded in vegetated areas for solely estuarine and marine estuarine dependent species and supports evidence of plasticity within these habitats. In general, the previously unstudied reed, P. australis showed the highest species richness and abundance of juvenile fishes overall, followed by, Z. capensis and the intertidal salt marsh species, S. maritima. These findings relate to many international trends on the value of vegetated areas as refugia for young fishes in estuaries. Fishes were also showing evidence of feeding and sheltering in these areas. By using conventional stomach contents and stable isotope methods (δ13C and δ15N signatures) on the abundant R. holubi in previously selected vegetation sites, it was clear that this species has a significant reliance on any of these habitats as their diets was largely comprised of a mixture of epiphytic algae and aquatic macrophytes. In addition, the diet of larger individuals (>80 mm) showed a greater component of invertebrates in previously unexplored habitats, which proves their omnivorous diet related to ontogenetic niche use. Knowledge of fine-scale habitat use by fishes is essential for conservation planning as exclusion zones can be optimised to limit anthropogenic influence on nursery use patterns in fishes. The availability of shallow water habitats (<60 cm) was assessed as an additional driver to explain the species diversity and richness of juvenile fishes within the lower reaches. These habitats are known as important nursery habitats providing numerous marine and estuarine spawned fishes with adequate refuge and food supply. This shallow water volume was measured by means of a two-man kayak using both the spring high and low tides in the lower reaches of these systems to assess juvenile assemblages. It was clear from the results that aquatic vegetation significantly adds to the volume of these areas and as a result, much greater fish density and species richness were observed. Generalized additive models showed that marine spawned species were particularly reliant on the availability of this shallow water along with submerged vegetation and additional environmental variables. The presence of structurally submerged vegetation typically characterized within shallow estuarine waters is commonly believed to reduce predation risk resulting in elevated densities of biota. Based on the current stock status and percentage of pristine breeding stock, five fish species classified as collapsed/overexploited was consistently found within these systems with an additional 14 species currently classified as exploited/vulnerable. Based on the current species richness and diversity, available habitat cover and knowledge regarding important recreational species, priority areas that require some form of legal protection in order to meet potential biodiversity targets, could be identified. It is a legal requirement in South Africa that all estuaries require management plans that should be based on good knowledge of priority habitats for fauna and flora. The identification of estuarine protected areas is seen as a mechanism for protecting a representative sample of the biodiversity accompanied by a complete range of environmental gradients and habitat types at a reasonable scale in order to maximize the protection of estuarine species.
- Full Text:
- Date Issued: 2018
- Authors: Nel, Larize
- Date: 2018
- Subjects: Mariculture -- South Africa , Fishes -- Ecology -- South Africa Fishes -- Food -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/32904 , vital:32396
- Description: Estuaries are among the most productive ecosystems worldwide as they provide important refuge and feeding areas for the juveniles of many marine species, many of which have recreational importance. The use of these nursery areas by juvenile fishes in South Africa are in need of further investigation and many critical areas such as shallow water creeks and vegetated habitats remain understudied. By using mixed-methods, estuarine fish assemblages were assessed in five permanently open estuaries in the Eastern Cape Province of South Africa. A total of 81 428 comprising 24 families and 40 species of fishes were sampled by means of a 50 m seine net (12 mm mesh) along the length of these systems that comprised of six equidistant sites during the summer recruitment period (October - December) of 2014 and 2015. A higher catch per unit effort (CPUE) was recorded in 2014 (68 875) compared to the following year where a decline of approximately 82% was observed in the catch (12 553) for all estuaries except the Kromme Estuary. Catches were mainly dominated by the marine estuarine dependent sparid, Rhabdosargus holubi and the solely estuarine clupeid, Gilchristella aestuaria. Species compositions and catch abundance with regards to historical catches showed that the abundance of many marine estuarine dependent juveniles as well as important recreational species have declined within these systems and are mainly attributed to marine overfishing and the exploitation of undersized individuals in estuarine nurseries. Juvenile fishes that occur in these estuaries utilize a range of vegetated habitats ranging from salt marsh creeks, Zostera capensis beds, Spartina maritima and previously unexplored Phragmites australis areas. Sampling was achieved by using passive, double-winged, six-hooped fyke nets, 1 mm mesh size that was secured in placed on the nocturnal flood tide at each inundated vegetated and adjacent unvegetated habitat types. Higher catches were frequently recorded in vegetated areas for solely estuarine and marine estuarine dependent species and supports evidence of plasticity within these habitats. In general, the previously unstudied reed, P. australis showed the highest species richness and abundance of juvenile fishes overall, followed by, Z. capensis and the intertidal salt marsh species, S. maritima. These findings relate to many international trends on the value of vegetated areas as refugia for young fishes in estuaries. Fishes were also showing evidence of feeding and sheltering in these areas. By using conventional stomach contents and stable isotope methods (δ13C and δ15N signatures) on the abundant R. holubi in previously selected vegetation sites, it was clear that this species has a significant reliance on any of these habitats as their diets was largely comprised of a mixture of epiphytic algae and aquatic macrophytes. In addition, the diet of larger individuals (>80 mm) showed a greater component of invertebrates in previously unexplored habitats, which proves their omnivorous diet related to ontogenetic niche use. Knowledge of fine-scale habitat use by fishes is essential for conservation planning as exclusion zones can be optimised to limit anthropogenic influence on nursery use patterns in fishes. The availability of shallow water habitats (<60 cm) was assessed as an additional driver to explain the species diversity and richness of juvenile fishes within the lower reaches. These habitats are known as important nursery habitats providing numerous marine and estuarine spawned fishes with adequate refuge and food supply. This shallow water volume was measured by means of a two-man kayak using both the spring high and low tides in the lower reaches of these systems to assess juvenile assemblages. It was clear from the results that aquatic vegetation significantly adds to the volume of these areas and as a result, much greater fish density and species richness were observed. Generalized additive models showed that marine spawned species were particularly reliant on the availability of this shallow water along with submerged vegetation and additional environmental variables. The presence of structurally submerged vegetation typically characterized within shallow estuarine waters is commonly believed to reduce predation risk resulting in elevated densities of biota. Based on the current stock status and percentage of pristine breeding stock, five fish species classified as collapsed/overexploited was consistently found within these systems with an additional 14 species currently classified as exploited/vulnerable. Based on the current species richness and diversity, available habitat cover and knowledge regarding important recreational species, priority areas that require some form of legal protection in order to meet potential biodiversity targets, could be identified. It is a legal requirement in South Africa that all estuaries require management plans that should be based on good knowledge of priority habitats for fauna and flora. The identification of estuarine protected areas is seen as a mechanism for protecting a representative sample of the biodiversity accompanied by a complete range of environmental gradients and habitat types at a reasonable scale in order to maximize the protection of estuarine species.
- Full Text:
- Date Issued: 2018