The host status of lemons for the false codling moth, Thaumatotibia leucotreta (Meyrick)(Lepidoptera: Tortricidae) with particular reference to export protocols
- Moore, Sean D, Kirkman, Wayne, Hattingh, Vaughan
- Authors: Moore, Sean D , Kirkman, Wayne , Hattingh, Vaughan
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452252 , vital:75115 , https://hdl.handle.net/10520/EJC176581
- Description: The South African citrus industry is dependent on export of fresh fruit to many markets around the world, with approximately 70% of South Africa's citrus crop being exported (CGA 2013). The false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), is recorded as a pest of citrus fruit in southern Africa (Newton 1998; Grout and Moore 2015). As a result of its endemism to sub-Saharan Africa (Moore 2002), certain export markets of importance for the South African citrus industry, such as Peoples Republic of China, U.S.A. and South Korea, regulate it as a quarantine pest.Control of the pest in the field can be highly effective, using a suite of integrated control options, applied with diligent management (Moore and Hattingh 2012). These can succeed in reducing T. leucotreta infestation by 97% or more (Moore et al. 2015). Such an integrated system, using the sterile insect technique as the mainstay of the programme, has succeeded in reducing moth catches by 99%, fruit infestation by 96% and export rejections by 89% in the Western Cape Province of South Africa, since the inception of the programme in 2007 (Barnes et al. 2015).
- Full Text:
- Date Issued: 2015
- Authors: Moore, Sean D , Kirkman, Wayne , Hattingh, Vaughan
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452252 , vital:75115 , https://hdl.handle.net/10520/EJC176581
- Description: The South African citrus industry is dependent on export of fresh fruit to many markets around the world, with approximately 70% of South Africa's citrus crop being exported (CGA 2013). The false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), is recorded as a pest of citrus fruit in southern Africa (Newton 1998; Grout and Moore 2015). As a result of its endemism to sub-Saharan Africa (Moore 2002), certain export markets of importance for the South African citrus industry, such as Peoples Republic of China, U.S.A. and South Korea, regulate it as a quarantine pest.Control of the pest in the field can be highly effective, using a suite of integrated control options, applied with diligent management (Moore and Hattingh 2012). These can succeed in reducing T. leucotreta infestation by 97% or more (Moore et al. 2015). Such an integrated system, using the sterile insect technique as the mainstay of the programme, has succeeded in reducing moth catches by 99%, fruit infestation by 96% and export rejections by 89% in the Western Cape Province of South Africa, since the inception of the programme in 2007 (Barnes et al. 2015).
- Full Text:
- Date Issued: 2015
Towards a PHP webshell taxonomy using deobfuscation-assisted similarity analysis
- Wrench, Peter M, Irwin, Barry V W
- Authors: Wrench, Peter M , Irwin, Barry V W
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429560 , vital:72622 , 10.1109/ISSA.2015.7335066
- Description: The abundance of PHP-based Remote Access Trojans (or web shells) found in the wild has led malware researchers to develop systems capable of tracking and analysing these shells. In the past, such shells were ably classified using signature matching, a process that is currently unable to cope with the sheer volume and variety of web-based malware in circulation. Although a large percentage of newly-created webshell software incorporates portions of code derived from seminal shells such as c99 and r57, they are able to disguise this by making extensive use of obfuscation techniques intended to frustrate any attempts to dissect or reverse engineer the code. This paper presents an approach to shell classification and analysis (based on similarity to a body of known malware) in an attempt to create a comprehensive taxonomy of PHP-based web shells. Several different measures of similarity were used in conjunction with clustering algorithms and visualisation techniques in order to achieve this. Furthermore, an auxiliary component capable of syntactically deobfuscating PHP code is described. This was employed to reverse idiomatic obfuscation constructs used by software authors. It was found that this deobfuscation dramatically increased the observed levels of similarity by exposing additional code for analysis.
- Full Text:
- Date Issued: 2015
- Authors: Wrench, Peter M , Irwin, Barry V W
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429560 , vital:72622 , 10.1109/ISSA.2015.7335066
- Description: The abundance of PHP-based Remote Access Trojans (or web shells) found in the wild has led malware researchers to develop systems capable of tracking and analysing these shells. In the past, such shells were ably classified using signature matching, a process that is currently unable to cope with the sheer volume and variety of web-based malware in circulation. Although a large percentage of newly-created webshell software incorporates portions of code derived from seminal shells such as c99 and r57, they are able to disguise this by making extensive use of obfuscation techniques intended to frustrate any attempts to dissect or reverse engineer the code. This paper presents an approach to shell classification and analysis (based on similarity to a body of known malware) in an attempt to create a comprehensive taxonomy of PHP-based web shells. Several different measures of similarity were used in conjunction with clustering algorithms and visualisation techniques in order to achieve this. Furthermore, an auxiliary component capable of syntactically deobfuscating PHP code is described. This was employed to reverse idiomatic obfuscation constructs used by software authors. It was found that this deobfuscation dramatically increased the observed levels of similarity by exposing additional code for analysis.
- Full Text:
- Date Issued: 2015
Trophic relationships of hake (Merluccius capensis and M. paradoxus) and sharks (Centrophorus squamosus, Deania calcea and D. profundorum) in the Northern (Namibia) Benguela Current region
- Iitembu, Johannes A, Richoux, Nicole B
- Authors: Iitembu, Johannes A , Richoux, Nicole B
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443830 , vital:74157 , https://hdl.handle.net/10520/EJC183122
- Description: The trophic relationships of two hake species (Merluccius capensis and M. paradoxus) and three shark species (Centrophorus squamosus, Deania calcea and D. profundorum) were investigated using nitrogen and carbon stable isotope signatures (15N and 13C) of their muscle tissues. The sharks were more enriched in 15N than the hake, an indication of the apex predator status of sharks. Among the sharks considered, C. squamosus occupied the highest trophic level and fed primarily on benthic prey. The two species of shark from the genus Deania were not different based on 15N or 13C, so they had similar diets. The 13C signatures indicated that M. capensis and sharks fed on prey derived from similar basal resources. However, there was a significant difference in 13C between M. paradoxus and all other species examined, suggesting that they occupied different feeding niches. Isotope-based populationmetrics showed narrower trophic ranges in sharks than M. capensis. Carbon and nitrogen ranges indicated that hake fed on a more diverse pool of carbon sources and had generally more enhanced trophic diversity in their feeding patterns than sharks. Among the species considered, C. squamosus occupied a unique isotopic space. Our results supported the hypothesis there are trophic overlaps among these species, but some interesting differentiation was revealed.
- Full Text:
- Date Issued: 2015
- Authors: Iitembu, Johannes A , Richoux, Nicole B
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443830 , vital:74157 , https://hdl.handle.net/10520/EJC183122
- Description: The trophic relationships of two hake species (Merluccius capensis and M. paradoxus) and three shark species (Centrophorus squamosus, Deania calcea and D. profundorum) were investigated using nitrogen and carbon stable isotope signatures (15N and 13C) of their muscle tissues. The sharks were more enriched in 15N than the hake, an indication of the apex predator status of sharks. Among the sharks considered, C. squamosus occupied the highest trophic level and fed primarily on benthic prey. The two species of shark from the genus Deania were not different based on 15N or 13C, so they had similar diets. The 13C signatures indicated that M. capensis and sharks fed on prey derived from similar basal resources. However, there was a significant difference in 13C between M. paradoxus and all other species examined, suggesting that they occupied different feeding niches. Isotope-based populationmetrics showed narrower trophic ranges in sharks than M. capensis. Carbon and nitrogen ranges indicated that hake fed on a more diverse pool of carbon sources and had generally more enhanced trophic diversity in their feeding patterns than sharks. Among the species considered, C. squamosus occupied a unique isotopic space. Our results supported the hypothesis there are trophic overlaps among these species, but some interesting differentiation was revealed.
- Full Text:
- Date Issued: 2015
What "global art" and current (re)turns fail to see: a modest counter-narrative of "not-another-biennial"
- Authors: Simbao, Ruth K
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147314 , vital:38625 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC176315
- Description: What is the scope of "global art" and who drives its framing within the current climate of 'corporate globalization' (Demos 2009 : 7, emphasis in original)? In what ways do the recent global turn and curatorial turn underwrite meaningful global inclusivity and visibility, and to what degree does this globally shared art constitute mutuality? Does "global art", including the accompanying process of biennialisation, allow for local narratives in a way that seriously accounts for a geopolitical view of contemporary art in the twenty-first century? While the inclusion of "new art worlds" in what Belting, Buddensieg and Weibel (2013) term "global art" is framed as a democratisation of contemporary art and the demise of the western art canon, it is important to raise questions regarding the blind spots of this supposedly global, post-1989 expansion.
- Full Text:
- Date Issued: 2015
- Authors: Simbao, Ruth K
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147314 , vital:38625 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC176315
- Description: What is the scope of "global art" and who drives its framing within the current climate of 'corporate globalization' (Demos 2009 : 7, emphasis in original)? In what ways do the recent global turn and curatorial turn underwrite meaningful global inclusivity and visibility, and to what degree does this globally shared art constitute mutuality? Does "global art", including the accompanying process of biennialisation, allow for local narratives in a way that seriously accounts for a geopolitical view of contemporary art in the twenty-first century? While the inclusion of "new art worlds" in what Belting, Buddensieg and Weibel (2013) term "global art" is framed as a democratisation of contemporary art and the demise of the western art canon, it is important to raise questions regarding the blind spots of this supposedly global, post-1989 expansion.
- Full Text:
- Date Issued: 2015
Willingness to pay for marine-based tourism in the Ponta do Ouro Partial Marine Reserve, Mozambique
- Daly, Clare A K, Fraser, Gavin C G, Snowball, Jeanette D
- Authors: Daly, Clare A K , Fraser, Gavin C G , Snowball, Jeanette D
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/473119 , vital:77608 , https://doi.org/10.2989/1814232X.2015.1012556
- Description: Marine and coastal ecosystems face widespread degradation largely because market failure hides the economic value of the goods and services they provide. Marine protected areas (MPAs) can serve as structures that ensure the continued functioning of marine and coastal ecosystem goods and services. Yet, to be effective and sustainable, MPAs must be able to prove their economic worth and generate revenue. User-fee systems are used commonly to partially finance multi-use MPAs. This study applies contingent valuation as a method of economic valuation within an MPA in southern Mozambique. Using a payment card and questionnaire from November 2012 to April 2013, this study determined the willingness to pay (WTP) of three user groups for access to the Ponta do Ouro Partial Marine Reserve. The study also investigated the potential for the reserve to increase revenues for conservation through the implementation of a user fee for marine-based activities. Probit and ordinary least squares (OLS) regressions were used to determine the effects of various independent variables on WTP. The OLS model found income, African residency and environmental awareness to be significant factors that influenced visitors' WTP for access to the reserve. The mean WTP was R 43.75 (South African rands) per person per day. Using data supplied by the reserve management, conservative estimated annual revenues based on the implementation of this fee amount ranged between R 1.46 million and R 3.3 million.
- Full Text:
- Date Issued: 2015
- Authors: Daly, Clare A K , Fraser, Gavin C G , Snowball, Jeanette D
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/473119 , vital:77608 , https://doi.org/10.2989/1814232X.2015.1012556
- Description: Marine and coastal ecosystems face widespread degradation largely because market failure hides the economic value of the goods and services they provide. Marine protected areas (MPAs) can serve as structures that ensure the continued functioning of marine and coastal ecosystem goods and services. Yet, to be effective and sustainable, MPAs must be able to prove their economic worth and generate revenue. User-fee systems are used commonly to partially finance multi-use MPAs. This study applies contingent valuation as a method of economic valuation within an MPA in southern Mozambique. Using a payment card and questionnaire from November 2012 to April 2013, this study determined the willingness to pay (WTP) of three user groups for access to the Ponta do Ouro Partial Marine Reserve. The study also investigated the potential for the reserve to increase revenues for conservation through the implementation of a user fee for marine-based activities. Probit and ordinary least squares (OLS) regressions were used to determine the effects of various independent variables on WTP. The OLS model found income, African residency and environmental awareness to be significant factors that influenced visitors' WTP for access to the reserve. The mean WTP was R 43.75 (South African rands) per person per day. Using data supplied by the reserve management, conservative estimated annual revenues based on the implementation of this fee amount ranged between R 1.46 million and R 3.3 million.
- Full Text:
- Date Issued: 2015
Conspecific alarm cue sensitivity by the estuarine calanoid copepod, Paracartia longipatella
- Wasserman, Ryan J, Kramer, Rachel, Vink, Tim J F, Froneman, P William
- Authors: Wasserman, Ryan J , Kramer, Rachel , Vink, Tim J F , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68062 , vital:29194 , https://doi.org/10.1111/aec.12135
- Description: Publisher version , Sensitivity to chemical cues associated with predation threat has been well observed in many freshwater zooplankters, yet few studies have highlighted such sensitivity in eury- and stenohaline metazoans. We aimed to assess sensitivity to conspecific chemical alarm cues in the estuarine copepod, Paracartia longipatella. Alarm cues associated with predation have been shown to have population level effects on certain zooplanktonic species. As such, we assessed the occurrence of such effects on population dynamics of P.longipatella over a 12 day period. Using experimental in situ mesocosms, we compared P.longipatella adult, copepodite and nauplii numbers between three treatments; one inoculated with conspecific alarm cues, one containing direct predation pressure (zooplanktivorous fish), and a control treatment containing no predation threat. Trends in population abundances were similar between the direct predation and alarm cue treatments for the six days of the experiment, decreasing in abundance. During the latter half of the study, however, P.longipatella abundances in the alarm cue treatment increased, while those in the presence of direct predation continued to decrease. In the treatment absent of any predation threat, P.longipatella abundances increased consistently over time for the duration of the study. We suggest that P.longipatella are indeed sensitive to conspecific alarm cues associated with predation threat. Furthermore, we propose that prolonged exposure to conspecific alarm cues in the absence of any real threat results in a reduction in sensitive to these cues.
- Full Text: false
- Date Issued: 2014
- Authors: Wasserman, Ryan J , Kramer, Rachel , Vink, Tim J F , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68062 , vital:29194 , https://doi.org/10.1111/aec.12135
- Description: Publisher version , Sensitivity to chemical cues associated with predation threat has been well observed in many freshwater zooplankters, yet few studies have highlighted such sensitivity in eury- and stenohaline metazoans. We aimed to assess sensitivity to conspecific chemical alarm cues in the estuarine copepod, Paracartia longipatella. Alarm cues associated with predation have been shown to have population level effects on certain zooplanktonic species. As such, we assessed the occurrence of such effects on population dynamics of P.longipatella over a 12 day period. Using experimental in situ mesocosms, we compared P.longipatella adult, copepodite and nauplii numbers between three treatments; one inoculated with conspecific alarm cues, one containing direct predation pressure (zooplanktivorous fish), and a control treatment containing no predation threat. Trends in population abundances were similar between the direct predation and alarm cue treatments for the six days of the experiment, decreasing in abundance. During the latter half of the study, however, P.longipatella abundances in the alarm cue treatment increased, while those in the presence of direct predation continued to decrease. In the treatment absent of any predation threat, P.longipatella abundances increased consistently over time for the duration of the study. We suggest that P.longipatella are indeed sensitive to conspecific alarm cues associated with predation threat. Furthermore, we propose that prolonged exposure to conspecific alarm cues in the absence of any real threat results in a reduction in sensitive to these cues.
- Full Text: false
- Date Issued: 2014
Modelling annual evapotranspiration in a semi-arid, African savanna: functional convergence theory, MODIS LAI and the Penman–Monteith equation
- Palmer, Anthony R, Weideman, Craig I, Finca, Andiswa, Everson, Colin S, Hanan, Niall P, Ellery, William F N
- Authors: Palmer, Anthony R , Weideman, Craig I , Finca, Andiswa , Everson, Colin S , Hanan, Niall P , Ellery, William F N
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144387 , vital:38341 , DOI: 10.2989/10220119.2014.931305
- Description: Accurately measuring evapotranspiration (ET) is essential if we are to derive reasonable estimates of production and water use for semi-arid savannas. Estimates of ET are also important in defining the health of an ecosystem and the quantity of water used by the vegetation when preparing a catchment-scale water balance. We derived ET0 from an automatic weather station 30 km west of Skukuza, Kruger National Park, South Africa using the Penman– Monteith equation, and then used the MODIS LAI to inform the model of canopy phenological dynamics. This result was compared with 173 days of ET measurements from the eddy covariance (ETec) system near Skukuza in 2007 as well as from the ET recorded by a large-aperture scintillometer at the same site in 2005. The model compared favourably with both sets of measured data and, when used independently of the eddy covariance data, ETMODIS predicted an annual ET of 378 mm in 2007 for the semi-arid savanna around the Skukuza flux site.
- Full Text:
- Date Issued: 2014
- Authors: Palmer, Anthony R , Weideman, Craig I , Finca, Andiswa , Everson, Colin S , Hanan, Niall P , Ellery, William F N
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144387 , vital:38341 , DOI: 10.2989/10220119.2014.931305
- Description: Accurately measuring evapotranspiration (ET) is essential if we are to derive reasonable estimates of production and water use for semi-arid savannas. Estimates of ET are also important in defining the health of an ecosystem and the quantity of water used by the vegetation when preparing a catchment-scale water balance. We derived ET0 from an automatic weather station 30 km west of Skukuza, Kruger National Park, South Africa using the Penman– Monteith equation, and then used the MODIS LAI to inform the model of canopy phenological dynamics. This result was compared with 173 days of ET measurements from the eddy covariance (ETec) system near Skukuza in 2007 as well as from the ET recorded by a large-aperture scintillometer at the same site in 2005. The model compared favourably with both sets of measured data and, when used independently of the eddy covariance data, ETMODIS predicted an annual ET of 378 mm in 2007 for the semi-arid savanna around the Skukuza flux site.
- Full Text:
- Date Issued: 2014
Simple, illustrated medicines information improves ARV knowledge and patient self-efficacy in limited literacy South African HIV patients:
- Dowse, Roslind, Barford, Kirsty-Lee, Browne, Sara H
- Authors: Dowse, Roslind , Barford, Kirsty-Lee , Browne, Sara H
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156698 , vital:40039 , DOI: 10.1080/09540121.2014.931559
- Description: Few studies have investigated antiretroviral (ARV) knowledge and self-efficacy in limited literacy patients. Using a randomized controlled study design, we investigated the influence of a simple pre-tested patient information leaflet (PIL) containing both text and illustrations on HIV- and ARV-related knowledge and on self-efficacy over six months in a limited literacy African population. The recruited patients were randomly allocated to either control (standard care) or intervention group (standard care plus illustrated PIL). HIV and medicines-related knowledge was evaluated with a 22-question test at baseline, one, three, and six months. Self-efficacy was assessed using a modified version of the HIV Treatment Adherence Self-Efficacy Scale.
- Full Text:
- Date Issued: 2014
- Authors: Dowse, Roslind , Barford, Kirsty-Lee , Browne, Sara H
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156698 , vital:40039 , DOI: 10.1080/09540121.2014.931559
- Description: Few studies have investigated antiretroviral (ARV) knowledge and self-efficacy in limited literacy patients. Using a randomized controlled study design, we investigated the influence of a simple pre-tested patient information leaflet (PIL) containing both text and illustrations on HIV- and ARV-related knowledge and on self-efficacy over six months in a limited literacy African population. The recruited patients were randomly allocated to either control (standard care) or intervention group (standard care plus illustrated PIL). HIV and medicines-related knowledge was evaluated with a 22-question test at baseline, one, three, and six months. Self-efficacy was assessed using a modified version of the HIV Treatment Adherence Self-Efficacy Scale.
- Full Text:
- Date Issued: 2014
Successful identification of the final instar nymph of Quintilia carinata (Thunberg)(Hemiptera: Cicadidae) by DNA extraction from the exuvium
- Bouwer, Nicolette, Midgley, John M, Timm, Alicia E, Villet, Martin H
- Authors: Bouwer, Nicolette , Midgley, John M , Timm, Alicia E , Villet, Martin H
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442347 , vital:73977 , https://doi.org/10.1080/00222933.2013.836759
- Description: Despite being taxonomically and phylogenetically informative, the morphology of the immature stages of cicadas has received comparatively superficial attention. One reason for this is the difficulty of positively identifying immature stages, particularly as these stages are fossorial. We present a method for identifying cicada exuviae using DNA sequence data and describe a set of characters and character states for the final instar nymph of Quintilia carinata (Thunberg). The identification of immature stages using molecular methods will increase our knowledge of African cicadas, allowing for the initiation of future phylogenetic and ecological comparisons.
- Full Text:
- Date Issued: 2014
- Authors: Bouwer, Nicolette , Midgley, John M , Timm, Alicia E , Villet, Martin H
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442347 , vital:73977 , https://doi.org/10.1080/00222933.2013.836759
- Description: Despite being taxonomically and phylogenetically informative, the morphology of the immature stages of cicadas has received comparatively superficial attention. One reason for this is the difficulty of positively identifying immature stages, particularly as these stages are fossorial. We present a method for identifying cicada exuviae using DNA sequence data and describe a set of characters and character states for the final instar nymph of Quintilia carinata (Thunberg). The identification of immature stages using molecular methods will increase our knowledge of African cicadas, allowing for the initiation of future phylogenetic and ecological comparisons.
- Full Text:
- Date Issued: 2014
Synthesis and characterization of novel zinc phthalocyanines as potential photosensitizers for photodynamic therapy of cancers
- Moeno, Sharon, Ermilov, E A, Kuzyniak, W, Höpfner, M, Krause, Rui W M
- Authors: Moeno, Sharon , Ermilov, E A , Kuzyniak, W , Höpfner, M , Krause, Rui W M
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123673 , vital:35471 , https://doi.org/10.1039/C3PP50393C
- Description: Two novel zinc phthalocyanines (Pcs): tetramethyl tetrakis-2,(3)-[(4-methyl-2-pyridyloxy)phthalocyaninato] zinc(II) (4) and (the negatively charged form) tetrakis-2,(3)-[(3-carboxylicacid-6-sulfanylpyridine)phthalocyaninato] zinc(II) (5), water soluble by virtue of their ionic substituent groups were synthesized. The spectroscopic properties of both compounds were determined and their photodynamic activities were investigated in a human tumor cell model. In aqueous media the two peripherally substituted water soluble Pcs are highly aggregated. The phototoxic activity of the two novel Pcs (Pc 4 and Pc 5; 0–20 μM) was shown to be time- and dose-dependent in human pancreatic carcinoid BON cells, leading to a reduction of tumor cells of >80% compared to the controls. The effectiveness of the treatment appeared to be attenuated by the aggregation of Pcs under aqueous conditions. Interestingly, even those cells that were not immediately killed by the photoactivated photosensitizer seemed to be affected by the Pc photodynamic activity, as a single PDT induced long-lasting effects on cell survival. Even 4 days after PDT, the number of surviving cells did not re-increase or still dropped, as compared to control cells. The underlying mechanism of this observation has to be deciphered in future investigations.
- Full Text:
- Date Issued: 2014
- Authors: Moeno, Sharon , Ermilov, E A , Kuzyniak, W , Höpfner, M , Krause, Rui W M
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123673 , vital:35471 , https://doi.org/10.1039/C3PP50393C
- Description: Two novel zinc phthalocyanines (Pcs): tetramethyl tetrakis-2,(3)-[(4-methyl-2-pyridyloxy)phthalocyaninato] zinc(II) (4) and (the negatively charged form) tetrakis-2,(3)-[(3-carboxylicacid-6-sulfanylpyridine)phthalocyaninato] zinc(II) (5), water soluble by virtue of their ionic substituent groups were synthesized. The spectroscopic properties of both compounds were determined and their photodynamic activities were investigated in a human tumor cell model. In aqueous media the two peripherally substituted water soluble Pcs are highly aggregated. The phototoxic activity of the two novel Pcs (Pc 4 and Pc 5; 0–20 μM) was shown to be time- and dose-dependent in human pancreatic carcinoid BON cells, leading to a reduction of tumor cells of >80% compared to the controls. The effectiveness of the treatment appeared to be attenuated by the aggregation of Pcs under aqueous conditions. Interestingly, even those cells that were not immediately killed by the photoactivated photosensitizer seemed to be affected by the Pc photodynamic activity, as a single PDT induced long-lasting effects on cell survival. Even 4 days after PDT, the number of surviving cells did not re-increase or still dropped, as compared to control cells. The underlying mechanism of this observation has to be deciphered in future investigations.
- Full Text:
- Date Issued: 2014
The impact of property rights to water resources on smallholder development in the Kat River valley
- Rantlo, Montoeli A, Fraser, Gavin C G
- Authors: Rantlo, Montoeli A , Fraser, Gavin C G
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/473066 , vital:77603
- Description: Property rights are social institutions that define and delimit the range of privileges granted to individuals of specific resources, such as land and water. They are the authority to determine different forms of control over resources thus determining the use, benefits and costs resulting from resource use. That is, they clearly specify who can use the resources, who can capture the benefits from the resources, and who should incur costs of any socially harmful impact resulting from the use of a resource. In order to be efficient property rights must be clearly defined by the administering institutions such as state, law and custom. They must be accepted, understood and respected by all the involved individuals and should be enforceable. The property rights influence the behaviour of individuals hence the impact on economic performance and development. The paper has attempted to determine how the situation of property rights to water resources affected the development of smallholders in the Kat River Valley. To capture data, a questionnaire was administered through face-to-face interviews. Institutional analysis and ANOVA were used for descriptive analysis to describe the property rights situation, security of property rights and the impact of property rights on the development of smallholder farming. The results showed that individual land rights holders have secure rights to water resources while communal smallholders and farmers on the invaded state land have insecure rights to water resources. The results from institutional analysis showed that the situation of property rights to water resources negatively affected development of all smallholder farmers in the Kat River Valley. The security of property rights to Kat River should be improved.
- Full Text:
- Date Issued: 2014
- Authors: Rantlo, Montoeli A , Fraser, Gavin C G
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/473066 , vital:77603
- Description: Property rights are social institutions that define and delimit the range of privileges granted to individuals of specific resources, such as land and water. They are the authority to determine different forms of control over resources thus determining the use, benefits and costs resulting from resource use. That is, they clearly specify who can use the resources, who can capture the benefits from the resources, and who should incur costs of any socially harmful impact resulting from the use of a resource. In order to be efficient property rights must be clearly defined by the administering institutions such as state, law and custom. They must be accepted, understood and respected by all the involved individuals and should be enforceable. The property rights influence the behaviour of individuals hence the impact on economic performance and development. The paper has attempted to determine how the situation of property rights to water resources affected the development of smallholders in the Kat River Valley. To capture data, a questionnaire was administered through face-to-face interviews. Institutional analysis and ANOVA were used for descriptive analysis to describe the property rights situation, security of property rights and the impact of property rights on the development of smallholder farming. The results showed that individual land rights holders have secure rights to water resources while communal smallholders and farmers on the invaded state land have insecure rights to water resources. The results from institutional analysis showed that the situation of property rights to water resources negatively affected development of all smallholder farmers in the Kat River Valley. The security of property rights to Kat River should be improved.
- Full Text:
- Date Issued: 2014
VC's welcome at the Rhodes University house committees and sub-wardens workshop
- Authors: Badat, Saleem
- Date: 2013-01-30
- Language: English
- Type: Text
- Identifier: vital:7914 , http://hdl.handle.net/10962/d1016464
- Full Text:
- Date Issued: 2013-01-30
- Authors: Badat, Saleem
- Date: 2013-01-30
- Language: English
- Type: Text
- Identifier: vital:7914 , http://hdl.handle.net/10962/d1016464
- Full Text:
- Date Issued: 2013-01-30
A high-level architecture for efficient packet trace analysis on gpu co-processors
- Nottingham, Alastair, Irwin, Barry V W
- Authors: Nottingham, Alastair , Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429572 , vital:72623 , 10.1109/ISSA.2013.6641052
- Description: This paper proposes a high-level architecture to support efficient, massively parallel packet classification, filtering and analysis using commodity Graphics Processing Unit (GPU) hardware. The proposed architecture aims to provide a flexible and efficient parallel packet processing and analysis framework, supporting complex programmable filtering, data mining operations, statistical analysis functions and traffic visualisation, with minimal CPU overhead. In particular, this framework aims to provide a robust set of high-speed analysis functionality, in order to dramatically reduce the time required to process and analyse extremely large network traces. This architecture derives from initial research, which has shown GPU co-processors to be effective in accelerating packet classification to up to tera-bit speeds with minimal CPU overhead, far exceeding the bandwidth capacity between standard long term storage and the GPU device. This paper provides a high-level overview of the proposed architecture and its primary components, motivated by the results of prior research in the field.
- Full Text:
- Date Issued: 2013
- Authors: Nottingham, Alastair , Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429572 , vital:72623 , 10.1109/ISSA.2013.6641052
- Description: This paper proposes a high-level architecture to support efficient, massively parallel packet classification, filtering and analysis using commodity Graphics Processing Unit (GPU) hardware. The proposed architecture aims to provide a flexible and efficient parallel packet processing and analysis framework, supporting complex programmable filtering, data mining operations, statistical analysis functions and traffic visualisation, with minimal CPU overhead. In particular, this framework aims to provide a robust set of high-speed analysis functionality, in order to dramatically reduce the time required to process and analyse extremely large network traces. This architecture derives from initial research, which has shown GPU co-processors to be effective in accelerating packet classification to up to tera-bit speeds with minimal CPU overhead, far exceeding the bandwidth capacity between standard long term storage and the GPU device. This paper provides a high-level overview of the proposed architecture and its primary components, motivated by the results of prior research in the field.
- Full Text:
- Date Issued: 2013
Automated classification of computer network attacks
- van Heerden, Renier, Leenen, Louise, Irwin, Barry V W
- Authors: van Heerden, Renier , Leenen, Louise , Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429622 , vital:72627 , 10.1109/ICASTech.2013.6707510
- Description: In this paper we demonstrate how an automated reasoner, HermiT, is used to classify instances of computer network based attacks in conjunction with a network attack ontology. The ontology describes different types of network attacks through classes and inter-class relationships and has previously been implemented in the Protege ontology editor. Two significant recent instances of network based attacks are presented as individuals in the ontology and correctly classified by the automated reasoner according to the relevant types of attack scenarios depicted in the ontology. The two network attack instances are the Distributed Denial of Service attack on SpamHaus in 2013 and the theft of 42 million Rand ($6.7 million) from South African Postbank in 2012.
- Full Text:
- Date Issued: 2013
- Authors: van Heerden, Renier , Leenen, Louise , Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429622 , vital:72627 , 10.1109/ICASTech.2013.6707510
- Description: In this paper we demonstrate how an automated reasoner, HermiT, is used to classify instances of computer network based attacks in conjunction with a network attack ontology. The ontology describes different types of network attacks through classes and inter-class relationships and has previously been implemented in the Protege ontology editor. Two significant recent instances of network based attacks are presented as individuals in the ontology and correctly classified by the automated reasoner according to the relevant types of attack scenarios depicted in the ontology. The two network attack instances are the Distributed Denial of Service attack on SpamHaus in 2013 and the theft of 42 million Rand ($6.7 million) from South African Postbank in 2012.
- Full Text:
- Date Issued: 2013
Classification of security operation centers
- Jacobs, Pierre, Arnab, Alapan, Irwin, Barry V W
- Authors: Jacobs, Pierre , Arnab, Alapan , Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429635 , vital:72628 , 10.1109/ISSA.2013.6641054
- Description: Security Operation Centers (SOCs) are a necessary service for organisations that want to address compliance and threat management. While there are frameworks in existence that addresses the technology aspects of these services, a holistic framework addressing processes, staffing and technology currently do not exist. Additionally, it would be useful for organizations and constituents considering building, buying or selling these services to measure the effectiveness and maturity of the provided services. In this paper, we propose a classification and rating scheme for SOC services, evaluating both the capabilities and the maturity of the services offered.
- Full Text:
- Date Issued: 2013
- Authors: Jacobs, Pierre , Arnab, Alapan , Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429635 , vital:72628 , 10.1109/ISSA.2013.6641054
- Description: Security Operation Centers (SOCs) are a necessary service for organisations that want to address compliance and threat management. While there are frameworks in existence that addresses the technology aspects of these services, a holistic framework addressing processes, staffing and technology currently do not exist. Additionally, it would be useful for organizations and constituents considering building, buying or selling these services to measure the effectiveness and maturity of the provided services. In this paper, we propose a classification and rating scheme for SOC services, evaluating both the capabilities and the maturity of the services offered.
- Full Text:
- Date Issued: 2013
Classification of security operation centers
- Jacobs, Pierre, Arnab, Alapan, Irwin, Barry V W
- Authors: Jacobs, Pierre , Arnab, Alapan , Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429785 , vital:72639 , 10.1109/ISSA.2013.6641054
- Description: Security Operation Centers (SOCs) are a necessary service for organisations that want to address compliance and threat management. While there are frameworks in existence that addresses the technology aspects of these services, a holistic framework addressing processes, staffing and technology currently do not exist. Additionally, it would be useful for organizations and constituents considering building, buying or selling these services to measure the effectiveness and maturity of the provided services. In this paper, we propose a classification and rating scheme for SOC services, evaluating both the capabilities and the maturity of the services offered.
- Full Text:
- Date Issued: 2013
- Authors: Jacobs, Pierre , Arnab, Alapan , Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429785 , vital:72639 , 10.1109/ISSA.2013.6641054
- Description: Security Operation Centers (SOCs) are a necessary service for organisations that want to address compliance and threat management. While there are frameworks in existence that addresses the technology aspects of these services, a holistic framework addressing processes, staffing and technology currently do not exist. Additionally, it would be useful for organizations and constituents considering building, buying or selling these services to measure the effectiveness and maturity of the provided services. In this paper, we propose a classification and rating scheme for SOC services, evaluating both the capabilities and the maturity of the services offered.
- Full Text:
- Date Issued: 2013
Customising a BBVC for Asterisk VoIP Services
- Oyedele, Y, Terzoli, Alfredo, Mufeti, K
- Authors: Oyedele, Y , Terzoli, Alfredo , Mufeti, K
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430942 , vital:72730 , https://doi.org/10.1007/978-1-4614-3558-7_62
- Description: Browser-based Voice over Internet Protocol Clients (BBVC) are used to access pre-determined VoIP services from VoIP service providers through Internet connections. For nomadic users within an organisa-tion’s Intranet, connections are made to the Internet to utilise these BBVC. An Intranet with an Asterisk Private Branch Exchange (PBX) as a VoIP provider however can be linked with any form of VoIP client to improve service accessibility for its users. This study aims to find a BBVC that can be customised to provide such accessibility within an Intranet. The study revealed that three BBVC are compatible. One of three BBVC was selected for customisation to provide nomadic acces-sibility to Asterisk. The functionality of the customised BBVC depended on the web technologies used and the available VoIP services.
- Full Text:
- Date Issued: 2013
- Authors: Oyedele, Y , Terzoli, Alfredo , Mufeti, K
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430942 , vital:72730 , https://doi.org/10.1007/978-1-4614-3558-7_62
- Description: Browser-based Voice over Internet Protocol Clients (BBVC) are used to access pre-determined VoIP services from VoIP service providers through Internet connections. For nomadic users within an organisa-tion’s Intranet, connections are made to the Internet to utilise these BBVC. An Intranet with an Asterisk Private Branch Exchange (PBX) as a VoIP provider however can be linked with any form of VoIP client to improve service accessibility for its users. This study aims to find a BBVC that can be customised to provide such accessibility within an Intranet. The study revealed that three BBVC are compatible. One of three BBVC was selected for customisation to provide nomadic acces-sibility to Asterisk. The functionality of the customised BBVC depended on the web technologies used and the available VoIP services.
- Full Text:
- Date Issued: 2013
Environmental ethics as processes of open-ended, pluralistic, deliberative enquiry
- Authors: Olvitt, Lausanne L
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437309 , vital:73368 , ISBN 9780203813331 , https://www.taylorfrancis.com/chapters/edit/10.4324/9780203813331-15/environmental-ethics-processes-open-ended-pluralistic-deliberative-enquiry-lausanne-olvitt
- Description: By the very nature of their work, environmental education re-searchers must engage with environmental philosophy and questions of values and ethics. But this terrain, despite being resourced with an apparently endless supply of typologies, an-thologies, and handbooks, can remain a vast and daunting philosophical sea—at least in my experience as a newcomer to the field, and possibly for many other scholars and re-searchers. This essay makes no claim to altering that and in-stead optimistically pursues Ball’s (2001, p. 89) suggestion that “there is much to be learned about, and from, the philosophical life-forms inhabiting these thickets and swamps.” My intention here is to review a relatively small but growing cluster of work in environmental ethics that proposes that:“Ethical positions are always open for discussion, re-examination, and revi-sion”(Jickling, 2004, p. 16) and are thus, by their very nature, open-ended, relational processes. My starting point in writing this essay is as an educator-researcher-environmentalist trying to explore what the field of environmental ethics has to offer in response to the question:“As educators, how can we learn and do more with others in the face of an unprecedented socioeco-logical crisis?”
- Full Text:
- Date Issued: 2013
- Authors: Olvitt, Lausanne L
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437309 , vital:73368 , ISBN 9780203813331 , https://www.taylorfrancis.com/chapters/edit/10.4324/9780203813331-15/environmental-ethics-processes-open-ended-pluralistic-deliberative-enquiry-lausanne-olvitt
- Description: By the very nature of their work, environmental education re-searchers must engage with environmental philosophy and questions of values and ethics. But this terrain, despite being resourced with an apparently endless supply of typologies, an-thologies, and handbooks, can remain a vast and daunting philosophical sea—at least in my experience as a newcomer to the field, and possibly for many other scholars and re-searchers. This essay makes no claim to altering that and in-stead optimistically pursues Ball’s (2001, p. 89) suggestion that “there is much to be learned about, and from, the philosophical life-forms inhabiting these thickets and swamps.” My intention here is to review a relatively small but growing cluster of work in environmental ethics that proposes that:“Ethical positions are always open for discussion, re-examination, and revi-sion”(Jickling, 2004, p. 16) and are thus, by their very nature, open-ended, relational processes. My starting point in writing this essay is as an educator-researcher-environmentalist trying to explore what the field of environmental ethics has to offer in response to the question:“As educators, how can we learn and do more with others in the face of an unprecedented socioeco-logical crisis?”
- Full Text:
- Date Issued: 2013
First year student performance in a test for computational thinking
- Gouws, Lindsey Ann, Bradshaw, Karen L, Wentworth, Peter E
- Authors: Gouws, Lindsey Ann , Bradshaw, Karen L , Wentworth, Peter E
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/477618 , vital:78104 , ISBN 9781450321129 , https://doi.org/10.1145/2513456.2513484
- Description: Computational thinking, a form of thinking and problem solving within computer science, has become a popular focus of research on computer science education. In this paper, we attempt to investigate the role that computational thinking plays in the experience of introductory computer science students at a South African university. To this end, we have designed and administered a test for computational thinking ability, and contrasted the results of this test with the class marks for the students involved. The results of this test give us an initial view of the abilities that students possess when entering the computer science course. The results indicate that students who performed well in the assessment have a favourable pass rate for their class tests, and specific areas of weakness have been identified. Finally, we describe the plan for a follow-up test to take place at the end of the course to determine how students' abilities have changed over a semester of studies.
- Full Text:
- Date Issued: 2013
- Authors: Gouws, Lindsey Ann , Bradshaw, Karen L , Wentworth, Peter E
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/477618 , vital:78104 , ISBN 9781450321129 , https://doi.org/10.1145/2513456.2513484
- Description: Computational thinking, a form of thinking and problem solving within computer science, has become a popular focus of research on computer science education. In this paper, we attempt to investigate the role that computational thinking plays in the experience of introductory computer science students at a South African university. To this end, we have designed and administered a test for computational thinking ability, and contrasted the results of this test with the class marks for the students involved. The results of this test give us an initial view of the abilities that students possess when entering the computer science course. The results indicate that students who performed well in the assessment have a favourable pass rate for their class tests, and specific areas of weakness have been identified. Finally, we describe the plan for a follow-up test to take place at the end of the course to determine how students' abilities have changed over a semester of studies.
- Full Text:
- Date Issued: 2013
TeleWeaver: an innovative telecommunication platform for marginalized communities in Africa
- Dalvit, Lorenzo, Gumbo, Sibukelo, Ntshinga, Lindikaya, Terzoli, Alfredo, Hansen, Susan
- Authors: Dalvit, Lorenzo , Gumbo, Sibukelo , Ntshinga, Lindikaya , Terzoli, Alfredo , Hansen, Susan
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431317 , vital:72763 , https://www.academic-bookshop.com/ourshop/prod_2659103-ECEG-2013-13th-European-Conference-on-eGovernment-Como-Italy-PRINT-version.html
- Description: Information and Communication Technologies for Development (ICT4D) is becoming an increasingly important and multi‐faceted area of research and software development. Particularly through provision via mobile devices, e‐services can potentially reach and improve the lives of millions of people living in marginalised areas. The efforts of many governments in sub‐Saharan Africa are frustrated by poor tele-communication infrastructure, lack of skills and unsustainable models of intervention. In this paper we describe the holistic solution offered by the TeleWeaver platform. The novel approach to the development of the software, the strong sense of social responsibility of the developers and the collaborative spirit that shaped the ecosystem of which Tele-Weaver is part, warrants the adoption of an innovative approach to its marketing and implementation. On the one hand, the project needs to provide returns on investment and generate profit for the key stake-holders (ie government at the local and national level, academia, indus-try and socio‐-entrepreneurs in the target community). On the other, it must benefit all members of the marginalised communities it is intended to serve as well as the global community of software developers. Tele-Weaver was developed in close collaboration with the community of Dwesa, a rural area on the Wild Cost of the Transkei regions in eastern South Africa.
- Full Text:
- Date Issued: 2013
- Authors: Dalvit, Lorenzo , Gumbo, Sibukelo , Ntshinga, Lindikaya , Terzoli, Alfredo , Hansen, Susan
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431317 , vital:72763 , https://www.academic-bookshop.com/ourshop/prod_2659103-ECEG-2013-13th-European-Conference-on-eGovernment-Como-Italy-PRINT-version.html
- Description: Information and Communication Technologies for Development (ICT4D) is becoming an increasingly important and multi‐faceted area of research and software development. Particularly through provision via mobile devices, e‐services can potentially reach and improve the lives of millions of people living in marginalised areas. The efforts of many governments in sub‐Saharan Africa are frustrated by poor tele-communication infrastructure, lack of skills and unsustainable models of intervention. In this paper we describe the holistic solution offered by the TeleWeaver platform. The novel approach to the development of the software, the strong sense of social responsibility of the developers and the collaborative spirit that shaped the ecosystem of which Tele-Weaver is part, warrants the adoption of an innovative approach to its marketing and implementation. On the one hand, the project needs to provide returns on investment and generate profit for the key stake-holders (ie government at the local and national level, academia, indus-try and socio‐-entrepreneurs in the target community). On the other, it must benefit all members of the marginalised communities it is intended to serve as well as the global community of software developers. Tele-Weaver was developed in close collaboration with the community of Dwesa, a rural area on the Wild Cost of the Transkei regions in eastern South Africa.
- Full Text:
- Date Issued: 2013