Ferrocenyl and organic novobiocin derivatives: synthesis and their in vitro biological activity
- Mbaba, Mziyanda, Mabhula, Amanda N, Boel, Natasha, Edkins, Adrienne L, Isaacs, Michelle, Hoppe, Heinrich C, Khanye, Setshaba D
- Authors: Mbaba, Mziyanda , Mabhula, Amanda N , Boel, Natasha , Edkins, Adrienne L , Isaacs, Michelle , Hoppe, Heinrich C , Khanye, Setshaba D
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66189 , vital:28914 , https://doi.org/10.1016/j.jinorgbio.2017.04.014
- Description: publisher version , A focused series of novobiocin derivatives containing a ferrocene unit together with their corresponding organic novobiocin analogues have been synthesized in modest to good yields. These compounds were screened for biological activity against a chloroquine-sensitive strain of Plasmodium falciparum (3D7) and human breast cancer cell line (HCC38). With the exception of compounds 5c and 5d, the general trend observed is that incorporation of the ferrocene moiety into novobiocin scaffold resulted in compounds 6a–d/6f showing enhanced activity compared to organic analogues 5a–b and 5e–f.
- Full Text: false
- Date Issued: 2017
- Authors: Mbaba, Mziyanda , Mabhula, Amanda N , Boel, Natasha , Edkins, Adrienne L , Isaacs, Michelle , Hoppe, Heinrich C , Khanye, Setshaba D
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66189 , vital:28914 , https://doi.org/10.1016/j.jinorgbio.2017.04.014
- Description: publisher version , A focused series of novobiocin derivatives containing a ferrocene unit together with their corresponding organic novobiocin analogues have been synthesized in modest to good yields. These compounds were screened for biological activity against a chloroquine-sensitive strain of Plasmodium falciparum (3D7) and human breast cancer cell line (HCC38). With the exception of compounds 5c and 5d, the general trend observed is that incorporation of the ferrocene moiety into novobiocin scaffold resulted in compounds 6a–d/6f showing enhanced activity compared to organic analogues 5a–b and 5e–f.
- Full Text: false
- Date Issued: 2017
Investigating the utilization of the secure hash algorithm to generate electromagnetic noise
- Frieslaar, Ibraheem, Irwin, Barry V W
- Authors: Frieslaar, Ibraheem , Irwin, Barry V W
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430222 , vital:72674 , https://doi.org/10.1145/3163080.3163089
- Description: This research introduces an electromagnetic (EM) noise generator known as the FRIES noise generator to mitigate and obfuscate Side Channel Analysis (SCA) attacks against a Raspberry Pi. The FRIES noise generator utilizes the implementation of the Secure Hash Algorithm (SHA) from OpenSSL to generate white noise within the EM spectrum. This research further contributes to the body of knowledge by demonstrating that the SHA implementation of libcrypto++ and OpenSSL had different EM signatures. It was further revealed that as a more secure implementation of the SHA was executed additional data lines were used, resulting in increased EM emissions. It was demonstrated that the OpenSSL implementations of the SHA was more optimized as opposed to the libcrypto++ implementation by utilizing less resources and not leaving the device in a bottleneck. The FRIES daemon added noise to the EM leakage which prevents the visual location of the AES-128 cryptographic implementation. Finally, the cross-correlation test demonstrated that the EM features of the AES-128 algorithm was not detected within the FRIES noise.
- Full Text:
- Date Issued: 2017
- Authors: Frieslaar, Ibraheem , Irwin, Barry V W
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430222 , vital:72674 , https://doi.org/10.1145/3163080.3163089
- Description: This research introduces an electromagnetic (EM) noise generator known as the FRIES noise generator to mitigate and obfuscate Side Channel Analysis (SCA) attacks against a Raspberry Pi. The FRIES noise generator utilizes the implementation of the Secure Hash Algorithm (SHA) from OpenSSL to generate white noise within the EM spectrum. This research further contributes to the body of knowledge by demonstrating that the SHA implementation of libcrypto++ and OpenSSL had different EM signatures. It was further revealed that as a more secure implementation of the SHA was executed additional data lines were used, resulting in increased EM emissions. It was demonstrated that the OpenSSL implementations of the SHA was more optimized as opposed to the libcrypto++ implementation by utilizing less resources and not leaving the device in a bottleneck. The FRIES daemon added noise to the EM leakage which prevents the visual location of the AES-128 cryptographic implementation. Finally, the cross-correlation test demonstrated that the EM features of the AES-128 algorithm was not detected within the FRIES noise.
- Full Text:
- Date Issued: 2017
Isolation, identification and genetic characterisation of a microsporidium isolated from carob moth, Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae)
- Lloyd, Melissa, Knox, Caroline M, Hill, Martin P, Moore, Sean D
- Authors: Lloyd, Melissa , Knox, Caroline M , Hill, Martin P , Moore, Sean D
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59874 , vital:27674 , https://doi.org/10.4001/003.025.0529
- Description: 'Microsporidia' is a term used for organisms belonging to the phylum Microspora, which contains approximately 187 genera and 1500 species (Corradi 2015). They are obligate intracellular parasites with no active metabolic stages of the life cycle occurring outside of the host cells (Franzen & Muller 1999; Garcia 2002; Tsai et al. 2003; Huang et al. 2004). They exhibit eukaryotic characteristics such as a membrane-bound nucleus, an intracytoplasmic membrane system, and chromosome separation occurs on mitotic spindles. However, they also exhibit prokaryotic characteristics such as possession of a 70S ribosome, lack of true mitochondria and peroxisomes, a simple version of the Golgi apparatus, and a small genome which is much less complex than those of most eukaryotes (Franzen & Muller 1999; Garcia 2002). Microspo- ridia are parasitic in all major groups of animals, both vertebrates and invertebrates (Sprague 1977; Franzen & Muller 1999). Microsporidia were first recognised as pathogens in silkworms by Nageli (1857), and now have been found to infect many hosts such as humans, insects, fish and mammals (Stentiford et al. 2016).
- Full Text:
- Date Issued: 2017
- Authors: Lloyd, Melissa , Knox, Caroline M , Hill, Martin P , Moore, Sean D
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59874 , vital:27674 , https://doi.org/10.4001/003.025.0529
- Description: 'Microsporidia' is a term used for organisms belonging to the phylum Microspora, which contains approximately 187 genera and 1500 species (Corradi 2015). They are obligate intracellular parasites with no active metabolic stages of the life cycle occurring outside of the host cells (Franzen & Muller 1999; Garcia 2002; Tsai et al. 2003; Huang et al. 2004). They exhibit eukaryotic characteristics such as a membrane-bound nucleus, an intracytoplasmic membrane system, and chromosome separation occurs on mitotic spindles. However, they also exhibit prokaryotic characteristics such as possession of a 70S ribosome, lack of true mitochondria and peroxisomes, a simple version of the Golgi apparatus, and a small genome which is much less complex than those of most eukaryotes (Franzen & Muller 1999; Garcia 2002). Microspo- ridia are parasitic in all major groups of animals, both vertebrates and invertebrates (Sprague 1977; Franzen & Muller 1999). Microsporidia were first recognised as pathogens in silkworms by Nageli (1857), and now have been found to infect many hosts such as humans, insects, fish and mammals (Stentiford et al. 2016).
- Full Text:
- Date Issued: 2017
Roundtable review: cold case: the elusive story of Julie Ward's murder
- Authors: Spencer, Lynda G
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/138894 , vital:37683 , https://doi.org/10.1080/23277408.2017.1362199
- Description: A Death Retold in Truth and Rumour: Kenya, Britain and the Julie Ward Murder by Grace Ahingila Musila is an extraordinary, captivating, thought-provoking and chilling account of the unsolved murder of Julie Ward. Musila points out that this book does not set out to reveal who murdered Julie Ward. Instead, as an academic, she is interested in examining the intertextual process between the rumours around this cold case and the evidence available in various published accounts, such as books, newspapers and court judgements.
- Full Text:
- Date Issued: 2017
- Authors: Spencer, Lynda G
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/138894 , vital:37683 , https://doi.org/10.1080/23277408.2017.1362199
- Description: A Death Retold in Truth and Rumour: Kenya, Britain and the Julie Ward Murder by Grace Ahingila Musila is an extraordinary, captivating, thought-provoking and chilling account of the unsolved murder of Julie Ward. Musila points out that this book does not set out to reveal who murdered Julie Ward. Instead, as an academic, she is interested in examining the intertextual process between the rumours around this cold case and the evidence available in various published accounts, such as books, newspapers and court judgements.
- Full Text:
- Date Issued: 2017
Street trees contribute to urban sustainability in South African towns
- Shackleton, Charlie M, Gwedla, Nanamhla
- Authors: Shackleton, Charlie M , Gwedla, Nanamhla
- Date: 2017
- Subjects: City planning -- Environmental aspects Sustainable urban development Community development -- Environmental aspects -- South Africa
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/54269 , vital:26440
- Description: Urban green spaces and trees are increasingly recognised as crucial elements in the quest for urban sustainability internationally, and for the promotion of urban liveability and quality of life in cities. So much so that many countries now have guidelines or regulations regarding either the amount of urban greenery that must be provided per capita, or the maximum distance that any dwelling can be from green spaces of stipulated sizes. For example, the European Union recently more than doubled its recommendation of 9 m2 of public green per person to 20 m2 per person.
- Full Text:
- Date Issued: 2017
- Authors: Shackleton, Charlie M , Gwedla, Nanamhla
- Date: 2017
- Subjects: City planning -- Environmental aspects Sustainable urban development Community development -- Environmental aspects -- South Africa
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/54269 , vital:26440
- Description: Urban green spaces and trees are increasingly recognised as crucial elements in the quest for urban sustainability internationally, and for the promotion of urban liveability and quality of life in cities. So much so that many countries now have guidelines or regulations regarding either the amount of urban greenery that must be provided per capita, or the maximum distance that any dwelling can be from green spaces of stipulated sizes. For example, the European Union recently more than doubled its recommendation of 9 m2 of public green per person to 20 m2 per person.
- Full Text:
- Date Issued: 2017
A Geopolitics of knowledge and the value of discomfort:
- Authors: Simbao, Ruth K
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146444 , vital:38526 , https://www.ru.ac.za/fineart/latestnews/alutacontinuadoingitfordaddytenyearson.html
- Description: In 2006, the short essay ‘Doing it for Daddy’ by visual artist Sharlene Khan caused controversy when it expressed the opinion that since 1994, ‘transformation’ in the visual arts field in South Africa seemed to have halted at the point of White women replacing White men in positions of power. It questioned this new position of dominance in institutions that remained colonially and racially untransformed. On the 16 and 17th of September 2016, the School of Fine Art at Rhodes University will host a one-day symposium ‘A luta Continua: Doing it for Daddy - Ten years on…’ which seeks to both commemorate that article and those who ‘speak up’, but also, fundamentally, to continue looking at the ways in which various social oppressions intersect in the fields of art history and visual arts in South Africa. Presenters include Khwezi Gule, Nontobeko Ntombela, Nomusa Makhubu, Same Mdluli, Fouad Asfour, Ruth Simbao, Sharlene Khan, students from Wits School of Arts and Rhodes Art History and Visual Culture, as well as a performance by visual artist Sikhumbuzo Makandula.
- Full Text:
- Date Issued: 2016
- Authors: Simbao, Ruth K
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146444 , vital:38526 , https://www.ru.ac.za/fineart/latestnews/alutacontinuadoingitfordaddytenyearson.html
- Description: In 2006, the short essay ‘Doing it for Daddy’ by visual artist Sharlene Khan caused controversy when it expressed the opinion that since 1994, ‘transformation’ in the visual arts field in South Africa seemed to have halted at the point of White women replacing White men in positions of power. It questioned this new position of dominance in institutions that remained colonially and racially untransformed. On the 16 and 17th of September 2016, the School of Fine Art at Rhodes University will host a one-day symposium ‘A luta Continua: Doing it for Daddy - Ten years on…’ which seeks to both commemorate that article and those who ‘speak up’, but also, fundamentally, to continue looking at the ways in which various social oppressions intersect in the fields of art history and visual arts in South Africa. Presenters include Khwezi Gule, Nontobeko Ntombela, Nomusa Makhubu, Same Mdluli, Fouad Asfour, Ruth Simbao, Sharlene Khan, students from Wits School of Arts and Rhodes Art History and Visual Culture, as well as a performance by visual artist Sikhumbuzo Makandula.
- Full Text:
- Date Issued: 2016
A multi-threading approach to secure VERIFYPIN
- Frieslaar, Ibraheem, Irwin, Barry V W
- Authors: Frieslaar, Ibraheem , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429244 , vital:72570 , https://ieeexplore.ieee.org/abstract/document/7802952
- Description: This research investigates the use of a multi-threaded framework as a software countermeasure mechanism to prevent attacks on the verifypin process in a pin-acceptance program. The implementation comprises of using various mathematical operations along side a pin-acceptance program in a multi-threaded environment. These threads are inserted randomly on each execution of the program to create confusion for the attacker. Moreover, the research proposes a more improved version of the pin-acceptance program by segmenting the pro-gram. The conventional approach is to check each character one at a time. This research takes the verifying process and separates each character check into its individual thread. Furthermore, the order of each verified thread is randomised. This further assists in the obfuscation of the process where the system checks for a correct character. Finally, the research demonstrates it is able to be more secure than the conventional countermeasures of random time delays and insertion of dummy code.
- Full Text:
- Date Issued: 2016
- Authors: Frieslaar, Ibraheem , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429244 , vital:72570 , https://ieeexplore.ieee.org/abstract/document/7802952
- Description: This research investigates the use of a multi-threaded framework as a software countermeasure mechanism to prevent attacks on the verifypin process in a pin-acceptance program. The implementation comprises of using various mathematical operations along side a pin-acceptance program in a multi-threaded environment. These threads are inserted randomly on each execution of the program to create confusion for the attacker. Moreover, the research proposes a more improved version of the pin-acceptance program by segmenting the pro-gram. The conventional approach is to check each character one at a time. This research takes the verifying process and separates each character check into its individual thread. Furthermore, the order of each verified thread is randomised. This further assists in the obfuscation of the process where the system checks for a correct character. Finally, the research demonstrates it is able to be more secure than the conventional countermeasures of random time delays and insertion of dummy code.
- Full Text:
- Date Issued: 2016
Improving Fidelity in Internet Simulation through Packet Injection
- Koorn, Craig, Irwin, Barry V W, Herbert, Alan
- Authors: Koorn, Craig , Irwin, Barry V W , Herbert, Alan
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427786 , vital:72462 , https://www.researchgate.net/profile/Barry-Ir-win/publication/327622877_Improving_Fidelity_in_Internet_Simulation_through_Packet_Injection/links/5b9a1a47458515310583fd8a/Improving-Fidelity-in-Internet-Simulation-through-Packet-Injection.pdf
- Description: This paper describes the of extension implemented to the NKM Internet simulation system, which allows for the improved of injection of packet traffic at arbitrary nodes, and the replay of previously recorded streams. The latter function allows for the relatively easy implementation of Internet Background Radiation (IBR) within the simulated portion of the Internet. This feature thereby enhances the degree of realism of the simulation, and allows for certain pre-determined traffic, such as scanning activity, to be injected and observed by client systems connected to the simulator.
- Full Text:
- Date Issued: 2016
- Authors: Koorn, Craig , Irwin, Barry V W , Herbert, Alan
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427786 , vital:72462 , https://www.researchgate.net/profile/Barry-Ir-win/publication/327622877_Improving_Fidelity_in_Internet_Simulation_through_Packet_Injection/links/5b9a1a47458515310583fd8a/Improving-Fidelity-in-Internet-Simulation-through-Packet-Injection.pdf
- Description: This paper describes the of extension implemented to the NKM Internet simulation system, which allows for the improved of injection of packet traffic at arbitrary nodes, and the replay of previously recorded streams. The latter function allows for the relatively easy implementation of Internet Background Radiation (IBR) within the simulated portion of the Internet. This feature thereby enhances the degree of realism of the simulation, and allows for certain pre-determined traffic, such as scanning activity, to be injected and observed by client systems connected to the simulator.
- Full Text:
- Date Issued: 2016
New evidence for the correlation of basalts of the Suurberg Group with the upper part of the Karoo basalt sequence of Lesotho:
- Authors: Marsh, J S Goonie
- Date: 2016
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/145122 , vital:38410 , ISBN 9783319408590 , https://link.springer.com/chapter/10.1007/978-3-319-40859-0_6
- Description: Tholeiitic basalts build the Mimosa Formation, the uppermost stratigraphic unit of the Suurberg Group in the northern part of the Algoa Basin. Exposures are very poor and the tectonic significance of the Suurberg rocks and the origin of the Mimosa basalts are contentious. Drilling of stratigraphic boreholes at four localities allowed detailed sampling of the basalts from two cores 90 km apart for geochemical, age and palaeomagnetic investigations.
- Full Text:
- Date Issued: 2016
- Authors: Marsh, J S Goonie
- Date: 2016
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/145122 , vital:38410 , ISBN 9783319408590 , https://link.springer.com/chapter/10.1007/978-3-319-40859-0_6
- Description: Tholeiitic basalts build the Mimosa Formation, the uppermost stratigraphic unit of the Suurberg Group in the northern part of the Algoa Basin. Exposures are very poor and the tectonic significance of the Suurberg rocks and the origin of the Mimosa basalts are contentious. Drilling of stratigraphic boreholes at four localities allowed detailed sampling of the basalts from two cores 90 km apart for geochemical, age and palaeomagnetic investigations.
- Full Text:
- Date Issued: 2016
Spotlight on the Art of Darkness: The Kin Artstudio
- Authors: Tshilumba Mukendi, J S
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146434 , vital:38525 , https://artafricamagazine.org/magazine-archive/?v=e4dd286dc7d7
- Description: Issue December 2016. What Really Matters.
- Full Text:
- Date Issued: 2016
- Authors: Tshilumba Mukendi, J S
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146434 , vital:38525 , https://artafricamagazine.org/magazine-archive/?v=e4dd286dc7d7
- Description: Issue December 2016. What Really Matters.
- Full Text:
- Date Issued: 2016
The effect of land-use on small mammal diversity inside and outside the Great Fish River Nature Reserve, Eastern Cape, South Africa
- Thondhlana, Gladman, Lagesse, Juliette V
- Authors: Thondhlana, Gladman , Lagesse, Juliette V
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67823 , vital:29150 , https://doi.org/10.1016/j.jaridenv.2016.03.006
- Description: Publisher version , This study investigated small mammal species diversity at 10 paired contrast sites along a fence line inside and outside the Great Fish River Nature Reserve (GFRNR), Eastern Cape, South Africa. The sites outside the GFRNR are used for subsistence land-based activities including livestock production and fuelwood harvesting. From 145 live captures, a total of 114 unique individuals of five small mammal species (four rodents and one elephant shrew) were recorded over 1170 trap nights. Average small mammal species diversity and abundance were significantly higher inside the reserve than outside. Human activities such as livestock grazing seemed to explain low levels of small mammal diversity and abundance at the communal sites. Vegetation variables showed a complex interplay with small mammal diversity. In general, high vegetation diversity had a positive influence on small mammal diversity though the influence of some environmental variables was species-dependent. We conclude that the GFRNR is effective in protecting small mammals but the findings raise questions around the influence of land use practices such as livestock grazing on biodiversity, especially given that local communities in South Africa are continuously seeking greater access to reserves for livestock grazing and other provisioning services.
- Full Text: false
- Date Issued: 2016
- Authors: Thondhlana, Gladman , Lagesse, Juliette V
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67823 , vital:29150 , https://doi.org/10.1016/j.jaridenv.2016.03.006
- Description: Publisher version , This study investigated small mammal species diversity at 10 paired contrast sites along a fence line inside and outside the Great Fish River Nature Reserve (GFRNR), Eastern Cape, South Africa. The sites outside the GFRNR are used for subsistence land-based activities including livestock production and fuelwood harvesting. From 145 live captures, a total of 114 unique individuals of five small mammal species (four rodents and one elephant shrew) were recorded over 1170 trap nights. Average small mammal species diversity and abundance were significantly higher inside the reserve than outside. Human activities such as livestock grazing seemed to explain low levels of small mammal diversity and abundance at the communal sites. Vegetation variables showed a complex interplay with small mammal diversity. In general, high vegetation diversity had a positive influence on small mammal diversity though the influence of some environmental variables was species-dependent. We conclude that the GFRNR is effective in protecting small mammals but the findings raise questions around the influence of land use practices such as livestock grazing on biodiversity, especially given that local communities in South Africa are continuously seeking greater access to reserves for livestock grazing and other provisioning services.
- Full Text: false
- Date Issued: 2016
The influence of photoperiod on the reproductive physiology of the greater red musk shrew: Crocidura flavescens
- Hoole, C, McKechnie, Andrew E, Parker, Daniel M, Bennett, Nigel C
- Authors: Hoole, C , McKechnie, Andrew E , Parker, Daniel M , Bennett, Nigel C
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70136 , vital:29624 , https://doi.org/10.1139/cjz-2015-0128
- Description: Photoperiodism involves the use of both absolute measures of day length and the direction in which day length is changing as a cue for regulating seasonal changes in physiology and behaviour so that birth and lactation coincide with optimal resource availability, increasing offspring survival. Induced ovulation and opportunistic breeding is often found in species that are predominantly solitary and territorial. In this study, the photoperiodic reproductive responses of male greater red musk shrews (Crocidura flavescens (I. Geoffroy Saint-Hilaire, 1827)) were investigated in the laboratory. The presence of spermatozoa regardless of the light cycle, suggest that although the shrews are photoresponsive, they may be capable of breeding throughout the year. Significantly greater testicular volume and eminiferous tubule diameter following exposure to a short day-light cycle suggests that these animals may have breeding peaks that correspond to short days. The presence of epidermal spines on the penis indicates that the shrew is likely also an induced ovulator. Flexible breeding patterns combined with induced ovulation affords this solitary species the greatest chance of reproductive success.
- Full Text: false
- Date Issued: 2016
- Authors: Hoole, C , McKechnie, Andrew E , Parker, Daniel M , Bennett, Nigel C
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70136 , vital:29624 , https://doi.org/10.1139/cjz-2015-0128
- Description: Photoperiodism involves the use of both absolute measures of day length and the direction in which day length is changing as a cue for regulating seasonal changes in physiology and behaviour so that birth and lactation coincide with optimal resource availability, increasing offspring survival. Induced ovulation and opportunistic breeding is often found in species that are predominantly solitary and territorial. In this study, the photoperiodic reproductive responses of male greater red musk shrews (Crocidura flavescens (I. Geoffroy Saint-Hilaire, 1827)) were investigated in the laboratory. The presence of spermatozoa regardless of the light cycle, suggest that although the shrews are photoresponsive, they may be capable of breeding throughout the year. Significantly greater testicular volume and eminiferous tubule diameter following exposure to a short day-light cycle suggests that these animals may have breeding peaks that correspond to short days. The presence of epidermal spines on the penis indicates that the shrew is likely also an induced ovulator. Flexible breeding patterns combined with induced ovulation affords this solitary species the greatest chance of reproductive success.
- Full Text: false
- Date Issued: 2016
The influence of photoperiod on the reproductive physiology of the greater red musk shrew: Crocidura flavescens
- Hoole, C, McKechnie, Andrew E, Parker, Daniel M, Bennett, Nigel C
- Authors: Hoole, C , McKechnie, Andrew E , Parker, Daniel M , Bennett, Nigel C
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70157 , vital:29626 , https://doi.org/10.1139/cjz-2015-0128
- Description: Photoperiodism involves the use of both absolute measures of day length and the direction in which day length is changing as a cue for regulating seasonal changes in physiology and behaviour so that birth and lactation coincide with optimal resource availability, increasing offspring survival. Induced ovulation and opportunistic breeding is often found in species that are predominantly solitary and territorial. In this study, the photoperiodic reproductive responses of male greater red musk shrews (Crocidura flavescens (I. Geoffroy Saint-Hilaire, 1827)) were investigated in the laboratory. The presence of spermatozoa regardless of the light cycle, suggest that although the shrews are photoresponsive, they may be capable of breeding throughout the year. Significantly greater testicular volume and eminiferous tubule diameter following exposure to a short day-light cycle suggests that these animals may have breeding peaks that correspond to short days. The presence of epidermal spines on the penis indicates that the shrew is likely also an induced ovulator. Flexible breeding patterns combined with induced ovulation affords this solitary species the greatest chance of reproductive success.
- Full Text:
- Date Issued: 2016
- Authors: Hoole, C , McKechnie, Andrew E , Parker, Daniel M , Bennett, Nigel C
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70157 , vital:29626 , https://doi.org/10.1139/cjz-2015-0128
- Description: Photoperiodism involves the use of both absolute measures of day length and the direction in which day length is changing as a cue for regulating seasonal changes in physiology and behaviour so that birth and lactation coincide with optimal resource availability, increasing offspring survival. Induced ovulation and opportunistic breeding is often found in species that are predominantly solitary and territorial. In this study, the photoperiodic reproductive responses of male greater red musk shrews (Crocidura flavescens (I. Geoffroy Saint-Hilaire, 1827)) were investigated in the laboratory. The presence of spermatozoa regardless of the light cycle, suggest that although the shrews are photoresponsive, they may be capable of breeding throughout the year. Significantly greater testicular volume and eminiferous tubule diameter following exposure to a short day-light cycle suggests that these animals may have breeding peaks that correspond to short days. The presence of epidermal spines on the penis indicates that the shrew is likely also an induced ovulator. Flexible breeding patterns combined with induced ovulation affords this solitary species the greatest chance of reproductive success.
- Full Text:
- Date Issued: 2016
Towards malicious network activity mitigation through subnet reputation analysis
- Herbert, Alan, Irwin, Barry V W
- Authors: Herbert, Alan , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427799 , vital:72463 , https://www.researchgate.net/profile/Barry-Ir-win/publication/327622788_Towards_Malicious_Network_Activity_Mitigation_through_Subnet_Reputation_Analysis/links/5b9a1a88458515310583fda6/Towards-Malicious-Network-Activity-Mitigation-through-Subnet-Reputation-Analysis.pdf
- Description: Analysis technologies that focus on partial packet rather than full packet analysis have shown promise in detection of malicious activity on net-works. NetFlow is one such emergent protocol that is used to log net-work flows through summarizing key features of them. These logs can then be exported to external NetFlow sinks and proper configuration can see effective bandwidth bottleneck mitigation occurring on net-works. Furthermore, each NetFlow source node is configurable with its own unique ID number. This feature enables a system that knows where a NetFlow source node ID number resides physically to say which network flows are occurring from which physical locations irre-spective of the IP addresses involved in these network flows.
- Full Text:
- Date Issued: 2016
- Authors: Herbert, Alan , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427799 , vital:72463 , https://www.researchgate.net/profile/Barry-Ir-win/publication/327622788_Towards_Malicious_Network_Activity_Mitigation_through_Subnet_Reputation_Analysis/links/5b9a1a88458515310583fda6/Towards-Malicious-Network-Activity-Mitigation-through-Subnet-Reputation-Analysis.pdf
- Description: Analysis technologies that focus on partial packet rather than full packet analysis have shown promise in detection of malicious activity on net-works. NetFlow is one such emergent protocol that is used to log net-work flows through summarizing key features of them. These logs can then be exported to external NetFlow sinks and proper configuration can see effective bandwidth bottleneck mitigation occurring on net-works. Furthermore, each NetFlow source node is configurable with its own unique ID number. This feature enables a system that knows where a NetFlow source node ID number resides physically to say which network flows are occurring from which physical locations irre-spective of the IP addresses involved in these network flows.
- Full Text:
- Date Issued: 2016
A quantitative analysis of microplastic pollution along the south-eastern coastline of South Africa
- Nel, Holly A, Froneman, P William
- Authors: Nel, Holly A , Froneman, P William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68032 , vital:29187 , https://doi.org/10.1016/j.marpolbul.2015.09.043
- Description: Publisher version , The extent of microplastic pollution (< 5 mm) in the southern hemisphere, particularly southern Africa, is largely unknown. This study aimed to evaluate microplastic pollution along the south-eastern coastline of South Africa, looking at whether bays are characterised by higher microplastic densities than open stretches of coastline in both beach sediment and surf-zone water. Microplastic (mean ± standard error) densities in the beach sediment ranged between 688.9 ± 348.2 and 3308 ± 1449 particles·m− 2, while those in the water column varied between 257.9 ± 53.36 and 1215 ± 276.7 particles·m− 3. With few exceptions there were no significant spatial patterns in either the sediment or water column microplastic densities; with little differences in density between bays and the open coast (P > 0.05). These data indicate that the presence of microplastics were not associated with proximity to land-based sources or population density, but rather is governed by water circulation.
- Full Text: false
- Date Issued: 2015
- Authors: Nel, Holly A , Froneman, P William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68032 , vital:29187 , https://doi.org/10.1016/j.marpolbul.2015.09.043
- Description: Publisher version , The extent of microplastic pollution (< 5 mm) in the southern hemisphere, particularly southern Africa, is largely unknown. This study aimed to evaluate microplastic pollution along the south-eastern coastline of South Africa, looking at whether bays are characterised by higher microplastic densities than open stretches of coastline in both beach sediment and surf-zone water. Microplastic (mean ± standard error) densities in the beach sediment ranged between 688.9 ± 348.2 and 3308 ± 1449 particles·m− 2, while those in the water column varied between 257.9 ± 53.36 and 1215 ± 276.7 particles·m− 3. With few exceptions there were no significant spatial patterns in either the sediment or water column microplastic densities; with little differences in density between bays and the open coast (P > 0.05). These data indicate that the presence of microplastics were not associated with proximity to land-based sources or population density, but rather is governed by water circulation.
- Full Text: false
- Date Issued: 2015
Enhancing cloud connectivity among NRENs in the SADC region through a novel institution cloud infrastructure framework
- Suresh, Nalina, Mbale, Jameson, Terzoli, Alfredo, Mufeti, Tulimevava K
- Authors: Suresh, Nalina , Mbale, Jameson , Terzoli, Alfredo , Mufeti, Tulimevava K
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430592 , vital:72702 , 10.1109/ETNCC.2015.7184830
- Description: It is increasingly being recognized that faster socioeconomic develop-ment in Africa is dependent upon the development of Information and Communication Technology (ICT) Infrastructure for the dissemination of data and educational services. The scalability and flexibility provided by Cloud services in terms of resource management, service provisioning and virtualization makes it an attractive system for use with educational and ICT services. The flexibility of pay-as-you-go models combined with the ability to scale computing, storage and/or networking resources makes Cloud computing an ideal candidate for use with education, re-search and scientific infrastructures. Notwithstanding its benefits, transi-tioning from a traditional IT infrastructure to a Cloud computing para-digm raises security concerns with respect to data storage, data trans-mission and user privacy. This paper presents on-going research for the development of Science, Technology and Innovation (STI) infra-structure for the distribution of Information Communication technologies (ICT) services in the African context. The Inter-Cloud Infrastructure Framework (ICIF) proposed, is conceived as a Cloud computing framework suitable for use with National Research and Education Net-works (NRENs) in the SADC region. The ICIF system is used to create an Inter-Cloud infrastructure, and helps NRENs transition from tradi-tional IT infrastructure systems to the Cloud computing paradigm. It also provides new functional/operational components and Cloud services to support the interconnection and/or interoperability among SADC NRENs through the ICIF infrastructure.
- Full Text:
- Date Issued: 2015
- Authors: Suresh, Nalina , Mbale, Jameson , Terzoli, Alfredo , Mufeti, Tulimevava K
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430592 , vital:72702 , 10.1109/ETNCC.2015.7184830
- Description: It is increasingly being recognized that faster socioeconomic develop-ment in Africa is dependent upon the development of Information and Communication Technology (ICT) Infrastructure for the dissemination of data and educational services. The scalability and flexibility provided by Cloud services in terms of resource management, service provisioning and virtualization makes it an attractive system for use with educational and ICT services. The flexibility of pay-as-you-go models combined with the ability to scale computing, storage and/or networking resources makes Cloud computing an ideal candidate for use with education, re-search and scientific infrastructures. Notwithstanding its benefits, transi-tioning from a traditional IT infrastructure to a Cloud computing para-digm raises security concerns with respect to data storage, data trans-mission and user privacy. This paper presents on-going research for the development of Science, Technology and Innovation (STI) infra-structure for the distribution of Information Communication technologies (ICT) services in the African context. The Inter-Cloud Infrastructure Framework (ICIF) proposed, is conceived as a Cloud computing framework suitable for use with National Research and Education Net-works (NRENs) in the SADC region. The ICIF system is used to create an Inter-Cloud infrastructure, and helps NRENs transition from tradi-tional IT infrastructure systems to the Cloud computing paradigm. It also provides new functional/operational components and Cloud services to support the interconnection and/or interoperability among SADC NRENs through the ICIF infrastructure.
- Full Text:
- Date Issued: 2015
Insecticidal activities and chemical composition of the essential oil from Tarchonanthus camphoratus (L.), leaves against Sitophilus zeamais Motschulsky, and Sitophilus oryzae (L.)
- Nanyonga, Sarah K, Opoku, Andy R, Lewu, Francis B, Oyedeji, Adebola O
- Authors: Nanyonga, Sarah K , Opoku, Andy R , Lewu, Francis B , Oyedeji, Adebola O
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/711 , vital:29660
- Description: The essential oil of Tarchonanthus camphoratus dry leaves growing in Kwa-Zulu Natal, South Africa was obtained by hydrodistillation and evaluated for its repellent effect, contact and fumigation toxicity against both Sitophilus zeamais and Sarocladium oryzae. Chemical composition of the essential oil was analysed by gas chromatography mass spectrometry (GC/MS). The study revealed that the essential oil of T. camphoratus had no contact and fumigation toxicity against stored insect pests, S. zeamais and S. oryzae. The oil, however, showed good repellent activity of over 50% after 24 h for all the concentrations used on both S. zeamais and S. oryzae. A total of 27 compounds accounting for 73% of the total oil composition were identified of which sesquiterpene hydrocarbons, (59.18%), were the most dominant. These results suggest that the essential oil of T. camphoratus could be considered a potential control agent of stored grain pests as a repellent.
- Full Text:
- Date Issued: 2015
- Authors: Nanyonga, Sarah K , Opoku, Andy R , Lewu, Francis B , Oyedeji, Adebola O
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/711 , vital:29660
- Description: The essential oil of Tarchonanthus camphoratus dry leaves growing in Kwa-Zulu Natal, South Africa was obtained by hydrodistillation and evaluated for its repellent effect, contact and fumigation toxicity against both Sitophilus zeamais and Sarocladium oryzae. Chemical composition of the essential oil was analysed by gas chromatography mass spectrometry (GC/MS). The study revealed that the essential oil of T. camphoratus had no contact and fumigation toxicity against stored insect pests, S. zeamais and S. oryzae. The oil, however, showed good repellent activity of over 50% after 24 h for all the concentrations used on both S. zeamais and S. oryzae. A total of 27 compounds accounting for 73% of the total oil composition were identified of which sesquiterpene hydrocarbons, (59.18%), were the most dominant. These results suggest that the essential oil of T. camphoratus could be considered a potential control agent of stored grain pests as a repellent.
- Full Text:
- Date Issued: 2015
Plasmodium falciparum Hop: detailed analysis on complex formation with Hsp70 and Hsp90
- Hatherley, Rowan, Clitheroe, Crystal-Leigh, Faya, Ngonidzashe, Tastan Bishop, Özlem
- Authors: Hatherley, Rowan , Clitheroe, Crystal-Leigh , Faya, Ngonidzashe , Tastan Bishop, Özlem
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125708 , vital:35810 , https://doi.10.1016/j.bbrc.2014.11.103
- Description: The heat shock organizing protein (Hop) is important in modulating the activity and co-interaction of two chaperones: heat shock protein 70 and 90 (Hsp70 and Hsp90). Recent research suggested that Plasmodium falciparum Hop (PfHop), PfHsp70 and PfHsp90 form a complex in the trophozoite infective stage. However, there has been little computational research on the malarial Hop protein in complex with other malarial Hsps. Using in silico characterization of the protein, this work showed that individual domains of Hop are evolving at different rates within the protein. Differences between human Hop (HsHop) and PfHop were identified by motif analysis. Homology modeling of PfHop and HsHop in complex with their own cytosolic Hsp90 and Hsp70 C-terminal peptide partners indicated excellent conservation of the Hop concave TPR sites bound to the C-terminal motifs of partner proteins. Further, we analyzed additional binding sites between Hop and Hsp90, and showed, for the first time, that they are distinctly less conserved between human and malaria parasite. These sites are located on the convex surface of Hop TPR2, and involved in interactions with the Hsp90 middle domain. Since the convex sites are less conserved than the concave sites, it makes their potential for malarial inhibitor design extremely attractive (as opposed to the concave sites which have been the focus of previous efforts).
- Full Text:
- Date Issued: 2015
- Authors: Hatherley, Rowan , Clitheroe, Crystal-Leigh , Faya, Ngonidzashe , Tastan Bishop, Özlem
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125708 , vital:35810 , https://doi.10.1016/j.bbrc.2014.11.103
- Description: The heat shock organizing protein (Hop) is important in modulating the activity and co-interaction of two chaperones: heat shock protein 70 and 90 (Hsp70 and Hsp90). Recent research suggested that Plasmodium falciparum Hop (PfHop), PfHsp70 and PfHsp90 form a complex in the trophozoite infective stage. However, there has been little computational research on the malarial Hop protein in complex with other malarial Hsps. Using in silico characterization of the protein, this work showed that individual domains of Hop are evolving at different rates within the protein. Differences between human Hop (HsHop) and PfHop were identified by motif analysis. Homology modeling of PfHop and HsHop in complex with their own cytosolic Hsp90 and Hsp70 C-terminal peptide partners indicated excellent conservation of the Hop concave TPR sites bound to the C-terminal motifs of partner proteins. Further, we analyzed additional binding sites between Hop and Hsp90, and showed, for the first time, that they are distinctly less conserved between human and malaria parasite. These sites are located on the convex surface of Hop TPR2, and involved in interactions with the Hsp90 middle domain. Since the convex sites are less conserved than the concave sites, it makes their potential for malarial inhibitor design extremely attractive (as opposed to the concave sites which have been the focus of previous efforts).
- Full Text:
- Date Issued: 2015
The relationship between concurrently measured SASS (South African Scoring System) and turbidity data archived in the South African River Health Programme’s Rivers Database
- Gordon, Andrew K, Griffin, Neil J, Palmer, Carolyn G
- Authors: Gordon, Andrew K , Griffin, Neil J , Palmer, Carolyn G
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: vital:7098 , http://hdl.handle.net/10962/d1015956
- Description: The need for monitoring the biological impacts of instream sediments has long been recognised, yet robust and scientifically defensible tools for doing so are still in the early stages of development because of the difficulties experienced by researchers in characterising the complicated mechanisms of biological effect elicited by sediment particles. Biological monitoring is one such tool, and this paper reports on the initial stages of a study to determine the most applicable approach for measuring the effects of instream sediments on aquatic macroinvertebrates in the South African context. In this first instance, the suitability of the rapid macroinvertebrate biomonitoring tool (the South African Scoring System) was investigated by determining the extent of the correlation between concurrently measured SASS metrics and turbidity data collected for the South African River Health Programme. All three SASS metrics – SASS score, number of taxa (NOT), and average score per taxon (ASPT) – were found to be significantly negatively correlated with turbidity, although variation in the data was high. Turbidity was found to be the major driver of change in ASPT. In contrast, electrical conductivity was the major driver of SASS scores and NOT, with turbidity a close second. When combined, electrical conductivity and turbidity accounted for 80 percent (SASS score) and 75 percent (NOT) of the variation in the regression model. Consequently, SASS metrics are a crude, but reliable, indicator of the negative biological implications of excessive instream sedimentation as measured by turbidity. A number of other potential biomonitoring approaches for detecting the impacts of fine sediment exposure are identified for further investigation: spatial analyses of macroinvertebrate assemblages; and the use of structural and functional metrics.
- Full Text:
- Date Issued: 2015
- Authors: Gordon, Andrew K , Griffin, Neil J , Palmer, Carolyn G
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: vital:7098 , http://hdl.handle.net/10962/d1015956
- Description: The need for monitoring the biological impacts of instream sediments has long been recognised, yet robust and scientifically defensible tools for doing so are still in the early stages of development because of the difficulties experienced by researchers in characterising the complicated mechanisms of biological effect elicited by sediment particles. Biological monitoring is one such tool, and this paper reports on the initial stages of a study to determine the most applicable approach for measuring the effects of instream sediments on aquatic macroinvertebrates in the South African context. In this first instance, the suitability of the rapid macroinvertebrate biomonitoring tool (the South African Scoring System) was investigated by determining the extent of the correlation between concurrently measured SASS metrics and turbidity data collected for the South African River Health Programme. All three SASS metrics – SASS score, number of taxa (NOT), and average score per taxon (ASPT) – were found to be significantly negatively correlated with turbidity, although variation in the data was high. Turbidity was found to be the major driver of change in ASPT. In contrast, electrical conductivity was the major driver of SASS scores and NOT, with turbidity a close second. When combined, electrical conductivity and turbidity accounted for 80 percent (SASS score) and 75 percent (NOT) of the variation in the regression model. Consequently, SASS metrics are a crude, but reliable, indicator of the negative biological implications of excessive instream sedimentation as measured by turbidity. A number of other potential biomonitoring approaches for detecting the impacts of fine sediment exposure are identified for further investigation: spatial analyses of macroinvertebrate assemblages; and the use of structural and functional metrics.
- Full Text:
- Date Issued: 2015
Interactive efficacies of Elephantorrhiza elephantina and Pentanisia prunelloides extracts and isolated compounds against gastrointestinal bacteria
- Mpofu, Smart J, Olivier, D K, Krause, Rui W M, Ndinteh, Derek T, Van Vuuren, S
- Authors: Mpofu, Smart J , Olivier, D K , Krause, Rui W M , Ndinteh, Derek T , Van Vuuren, S
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124122 , vital:35552 , https://doi.org/10.1016/j.sajb.2014.07.002
- Description: Elephantorrhiza elephantina (Burch.) Skeels (Fabaceae) and Pentanisia prunelloides (Klotzsch ex Eckl. & Zeyh.) Walp. (Rubiaceae) are two medicinal plants used extensively in southern Africa to treat various ailments. Often, decoctions and infusions from these two plants are used in combination specifically for stomach ailments. The antimicrobial activities of the methanol and aqueous extracts of the rhizomes of the two plants, as well as the two active ingredients from the plants [(−)-epicatechin and palmitic acid] have been determined apart and in combination against Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 8739) and Bacillus cereus (ATCC 11778). The minimum inhibitory concentration (MIC) values for the aqueous (0.50–16.00 mg/mL) and methanol (0.20–16.00 mg/mL) extracts independently demonstrated varied efficacies depending on the pathogen of study. When the two plants were combined in 1:1 ratios, synergistic to additive interactions (ΣFIC values 0.19–1.00) were noted. Efficacy for the two major compounds ranged between 0.13–0.63 mg/mL and mainly synergistic interactions were noted against E. faecalis and E. coli. The predominantly synergistic interactions noted between E. elephantina and P. prunelloides and major compounds, when tested in various ratios against these pathogens, provide some validation as to the traditional use of these two plants to treat bacterial gastrointestinal infections.
- Full Text:
- Date Issued: 2014
- Authors: Mpofu, Smart J , Olivier, D K , Krause, Rui W M , Ndinteh, Derek T , Van Vuuren, S
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124122 , vital:35552 , https://doi.org/10.1016/j.sajb.2014.07.002
- Description: Elephantorrhiza elephantina (Burch.) Skeels (Fabaceae) and Pentanisia prunelloides (Klotzsch ex Eckl. & Zeyh.) Walp. (Rubiaceae) are two medicinal plants used extensively in southern Africa to treat various ailments. Often, decoctions and infusions from these two plants are used in combination specifically for stomach ailments. The antimicrobial activities of the methanol and aqueous extracts of the rhizomes of the two plants, as well as the two active ingredients from the plants [(−)-epicatechin and palmitic acid] have been determined apart and in combination against Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 8739) and Bacillus cereus (ATCC 11778). The minimum inhibitory concentration (MIC) values for the aqueous (0.50–16.00 mg/mL) and methanol (0.20–16.00 mg/mL) extracts independently demonstrated varied efficacies depending on the pathogen of study. When the two plants were combined in 1:1 ratios, synergistic to additive interactions (ΣFIC values 0.19–1.00) were noted. Efficacy for the two major compounds ranged between 0.13–0.63 mg/mL and mainly synergistic interactions were noted against E. faecalis and E. coli. The predominantly synergistic interactions noted between E. elephantina and P. prunelloides and major compounds, when tested in various ratios against these pathogens, provide some validation as to the traditional use of these two plants to treat bacterial gastrointestinal infections.
- Full Text:
- Date Issued: 2014